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Correspondence
Anaesthesia for organ donation
in the brainstem dead
I warmly applaud your editorial `Anaesthesia for organ donation in the brainstem dead ± Why bother?' (Anaesthesia
2000; 55: 105±6). Many practitioners
have felt a deep unease since the
Conference of Medical Royal Colleges
and their Faculties (UK) in 1976 and
1979 defined brain stem death in the
UK. This conference was intended to
facilitate beating heart organ donation
but only concluded that the state of
brain stem death was a state of unsurvivable coma and, quite rightly, stopped
short of equating it to death itself.
Many anaesthetists clearly have been
very uneasy about the transplant lobby's
rather rash assumption that organ
donors do not require anaesthesia.
Many anaesthetists do administer an
anaesthetic to these patients, with
good reason, as set out in your editorial.
The problem the transplant lobby have
with giving donors an anaesthetic is the
perceived additional difficulty in telling
the donor's relatives that the donor is
not dead but in an unsurvivable coma.
It is time all anaesthetists realised that
to not administer an anaesthetic to a
donor (who is not by any definition
dead) is to commit an act of possibly
barbarous dishonesty. Whatever the
effect on donor numbers, one cannot
condone such action. Our personal
belief is that more honesty, and not
less, would help to overcome some of
the reservations that some doctors share
over organ transplantation. One can
hope that this would increase rather
than decrease organ supply.
J. Wace
M. Kai
Queen Alexandra Hospital,
Portsmouth PO6 3LY, UK
Young and Matta (Anaesthesia 2000; 55:
105±6) do well to remind us of the
alarming haemodynamic responses to
the pain of surgery during organ
retrieval operations. It is convenient to
dismiss these as spinal reflexes, yet spinal
reflexes of this immediacy have never
been demonstrated in experimental
animals. Even if they were to be
demonstrated, Occam's Razor would
still dictate that these responses are
mediated by the brain stem until
proven otherwise. The only safe and
reasonable conclusion to draw from this
is that the current UK brainstem death
criteria do not suffice to demonstrate
that the entire brain stem is invariably
dead.
The ethical question we have to ask
ourselves therefore is this: would we be
content to cremate the body of a loved
one in the knowledge that it would
withdraw its limbs and that there would
be a sharp rise in heart rate and blood
pressure when it entered the furnace? If
we would not, then we have no right to
inflict a similar fate on an un-anaesthetised organ donor.
Recent events have shown just how
squeamish the public is when it hears
about organs being removed many
hours after circulation has ceased.
What sort of reaction do you imagine
we would get if we told them honestly
about these responses in beating-heart
organ donors? Many of us have been
pressing for years for a complete
reappraisal of the UK brainstem death
criteria. Until that happens, anaesthetising organ donors is probably the best
pragmatic fudge available to us.
P. J. Keep
Norfolk and Norwich Hospital,
Norwich NRI5 2YR, UK
Chemoprophylaxis for
meningococcal disease in
healthcare workers
Since the successful implementation of
Hib vaccine in 1994, Neisseri meningitidis
has become the leading infectious cause
of death in childhood in the UK. More
than 2000 cases of meningococcal
disease are reported each year, with a
mortality rate of about 10%, rising to
50% in severe cases. In 1999, 104 cases
of meningococcal disease were admitted
to our paediatric intensive care unit
(PICU), of which 100 (98%) were
retrieved from various referral hospitals
in the region. As part of the retrieval
team for the PICU, we are frequently
asked for guidance regarding self-prophylaxis by the referring healthcare
workers, especially from anaesthetists
who have had close involvement with
the resuscitation of the patient. In our
series, anaesthetists at the referring
hospitals performed airway management manoeuvres in 85% of cases,
some with frank pulmonary oedema,
and therefore potentially exposed to
nasopharyngeal secretion and sputum.
There is controversy regarding this
issue as there is little scientific data on
which to assess risk. Nasopharyngeal
carriage of meningococci is common
(up to 10% of the population may carry a
number of meningococcal strains). The
disease is spread via droplet transmission
All correspondence should be addressed to Professor M. Harmer, Editor of Anaesthesia, Department of Anaesthetics, University of Wales College of
Medicine, Heath Park, Cardiff CF14 4XN, UK.
Letters (two copies) must be typewritten on one side of the paper only and double spaced with wide margins. Copy should be prepared in the usual
style and format of the Correspondence section. Authors must follow the advice about references and other matters contained in the Notice to
Contributors to Anaesthesia printed at the back of each issue. The degree and diplomas of each author must be given in a covering letter personally
signed by all the authors.
Correspondence presented in any other style or format may be the subject of considerable delay and may be returned to the author for revision. If the
letter comments on a published article in Anaesthesia, please send three copies; otherwise two copies of your letter will suffice.
590
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through close contact and viable organisms may be found in the nasopharynx
of presenting cases even after community administration of penicillin. Only a
few cases arise from contact, and a
quoted figure of 0.5% of all cases are
associated with family contact. There
has been one reported case of a French
paediatrician contracting severe meningococcal infection one week after
having intubated a comatose patient
with meningococcal disease.
Prophylaxis for healthcare workers
has recently been reviewed by Pollard
[1], who suggested that the offer of
antibiotic prophylaxis should be
extended to all healthcare workers
who have had direct exposure to
nasopharyngeal secretions from a patient
with meningococcal infection. This is
to reduce colonisation of recipients and
their close contacts with virulent strains.
This advice concurs with that given in
the United States, but goes against UK
guidelines, which stipulate that chemoprophylaxis (rifampicin, ciprofloxacin
or ceftriaxone) should only be given
to those who administered mouth-tomouth resuscitation to patients with
meningococcal disease [2].
Pollard's advice raised concerns in the
microbiological community that widespread chemoprophylaxis would have
implications regarding the abolition of
the recipient's own protective nasopharyngeal flora, leading to the acquisition
of pathogenic flora. There were also
concerns regarding the emergence of
resistance to rifampicin as well as to
ciprofloxacin, and its financial implications [3±6].
The issue of vaccination is also
contentious. A protein±polysaccharide
conjugate vaccine against group C
meningococcal disease has recently
been introduced in the immunisation
schedule in the UK and is expected to
decrease cases due to this serogroup.
However, there is no effective vaccine
for the meningococcus B serogroup,
which causes approximately 40% of
serious infections, and likely to increase
following the introduction of the serogroup C vaccine. Thus, vaccination
would not remove the perceived need
for chemoprophylaxis.
More elementary to the above
q 2000 Blackwell Science Ltd
discussion is the role of preventative
measures during the early management
of meningococcal cases. Barrier protection in the form of masks and perhaps
goggles should be worn when intubating children presenting with the features
of meningococcal disease, who have not
had 24 h of antibiotic therapy. These
basic precautions significantly reduce
the risk of disease transmission during
resuscitation.
In view of this controversy, what is
the best practice? Chemoprophylaxis for
health workers involved in airway
manoeuvres in patients who have frank
pulmonary oedema seems logical but is
not evidence based. Consultants in
communicable disease control have a
difficult task of allaying the anxiety of
the exposed personnel whilst assessing
the risk of disease transmission in each
individual case.
Clearly there is a need for a review of
current UK guidelines and for distribution of information regarding the risk to
healthcare workers in these circumstances. Until then, ignorance of the
estimated risk will result in controversy
and cases such as that of the French
paediatrician will continue to alarm
those exposed to the disease.
A. Cooney
N. Mehta
St Mary's Hospital,
London W2 1NY, UK
References
1 Pollard AJ, Begg N. Meningococcal
disease and healthcare workers. British
Medical Journal 1999; 319: 1147±8.
2 Anon. Control of meningococcal
disease: guidance for Consultants in
communicable disease control. PHLS
Meningococcal Infections Working
Group and Public health Medicine
Environmental Group. Communicable
Disease Report 1995; 5:R: 189±95.
3 Flood TJ. Use of antibiotics to prevent
Meningococcal infection in Healthcare
Workers. e-Letter. E-British Medical
Journal 1999; 12 November.
4 Wilcox MH, Modi N. Management of
meningococcal sepsis and risk of
infection in healthcare workers. e-Letter.
E-British Medical Journal 1999; 10
November.
5 Gilmore A, et al. Meningococcal
Disease in healthcare workers:
developing appropriate guidelines. eLetter. E-British Medical Journal 1999; 18
November.
6 Cowling D. Meningococcal
prophylaxis. e-Letter. E-British Medical
Journal 1999; 20 November.
Incidence of blood-borne
infectious micro-organisms:
would you still not wear
gloves?
Several surveys have shown that anaesthetists often do not care for precautions
for preventing transmission of bloodborne infectious agents [1±4]. For
example, still a high proportion of
anaesthetists do not wear gloves routinely during anaesthetic practice [1±4].
The proportion of anaesthetists wearing
gloves increases when they know that
the patient has a blood-borne virus [1, 2],
but screening for viruses is not done in
many hospitals, and thus its incidence in
patients undergoing surgery is not
known.
At our hospital in Japan, routine
screening is done and a record is kept
for blood-borne infectious viruses in all
patients who are scheduled for elective
surgery under either general or regional
anaesthesia. In 6437 patients who
underwent surgery during the last
2 years, at least one infectious virus
was detected in 534 patients (8.3%)
(Table 1). In addition, infection of
methicillin-resistant Staphylococcus aureus
(MRSA) was reported in 166 patients
(2.6%). Although these figures may
differ from other regions, the results
indicate that anaesthetists may frequently contact with infectious microorganisms. If one gives anaesthesia for
5±10 patients a day, one may encounter
patients with infectious viruses almost
every day. Isn't it time to change our
attitude and start wearing gloves routinely and washing hands between each
case?
T. Asai
S. Matsumoto
K. Shingu
591
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Anaesthesia, 2000, 55, pages 590±619
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Table 1 The number and incidence of blood-borne infectious viruses in patients
undergoing elective surgery under either general or regional anaesthesia (n 6437)
Hepatitis B virus (HBV)
Hepatitis C virus (HCV)
Human immunodeficiency virus (HIV)
At least one of above positive
Kansai Medical University,
Moriguchi City,
Osaka, 570±8507, Japan
References
1 O'Donnell NG, Asbury AJ. The
occupational hazard of human
immunodeficiency virus and hepatitis B
virus infection. I. Perceived risks and
preventative measures adopted by
anaesthetists: a postal survey. Anaesthesia
1992; 47: 923±8.
2 McNamara JT, Stacey SG. Poor
anaesthetist hygienic practice ± a
problem across all grades of anaesthetist.
Anaesthesia 1999; 54: 718±19.
3 El Mikatti N, Dillon P, Healy TEJ.
Hygienic practices of consultant
anaesthetists: a survey in the NorthWest region of the UK. Anaesthesia
1999; 54: 1±3.
4 Harrison CA, Rogers DW, Rosen M.
Blood contamination of anaesthetic and
related staff. Anaesthesia 1990; 45: 831±
3.
Alzheimer's disease and
anaesthesia
There is an increasing awareness that
head injury resulting in loss of consciousness is associated with an increased
risk of Alzheimer's disease [1]. Recent
studies indicate that deposition of amyloid beta occurs in approximately one
third of individuals who die after severe
head injury [2]. Apolipo protein E
(ApoE) is a transport system prominent
in response to injury prompting the
need to better understand the relationship between acute brain injury and
the development of neurodegeneration
such as Alzheimer's disease [3]. All
attention to date has focused on head
injury, whilst other comparable hypoxic
592
140
407
1
534
(2.2%)
(6.3%)
(0.0001%)
(8.3%)
ischaemic brain insults have not been
evaluated to see whether or not they
may prove to be an epidemiological risk
factor for the development, or possibly
influence progression of this group of
neurological diseases. Alzheimer's disease is the commonest cause of dementia overall, accounting for more than
50% of all cases, with an exponential
increase in incidence with advancing
age. Such patients, either before clinical
signs or in early symptomatic disease,
may well require to undergo general
anaesthesia. There is to date no study
addressing whether anaesthesia is associated with thereafter the presentation
or worsening of Alzheimer's disease. We
report a case in which deterioration
after anaesthesia was evident and speculate on the need for observational
studies, possibly combined with ApoE
genotyping to ensure that our observation does not have wider more generalised implications.
We recently reviewed a case in which
a patient with Alzheimer's disease deteriorated after an anaesthetic. The literature is silent on any interaction.
This patient, a man aged 67 years,
was scheduled to have bilateral varicose
veins. He was obese (108 kg; 1.5 m
height). He had intermittent hypertension (200/95; 190/110) but was not
being treated. His pre-operative blood
pressure was 160/90. He had longstanding right bundle branch block. His
ECG showed no evidence of left
ventricular hypertrophy. His peak
expiratory flow rate was normal.
He had suffered bouts of weepiness,
feeling depressed and difficulty in sleeping and was having a selective serotonin
reuptake inhibitor (Lustralw ± sertraline
hydrochloride). On admission, his wife
reported that he was forgetful and
confused, and might start weeping if
he did not know where she was.
Twenty years before he had had
varicose veins operated upon. He
reported that he was awake during the
surgery. That record was not available.
In the 8 years before this operation he
had three genito-urinary operations, a
prostatectomy, cystoscopy and internal
urethrotomy, without any complications.
On this occasion recorded `routine
monitoring' was recorded, but there
were no records of oxygen saturations
although there were of blood pressure.
The blood pressure varied between
115/75 and 95/55. These were lower
than the lowest figures of any of the
other previous anaesthetics. The operation took 90 min. He had propofol
200 mg, nitrous oxide, halothane and
alfentanil 1 mg. He breathed spontaneously through a laryngeal mask
airway. He was in the prone position
for some of the period. The operation
was difficult.
On return to the ward, he was restless
and nauseous. He received cyclimorphw (morphine 10 mg, cyclizine
39.01 mg). He was confused postoperatively and retained in hospital for 3 days.
On the third day he went home and at
midnight got up, removed the bandages
and accused his wife of `cutting him'.
His general practitioner was called at
3.00 a.m. and administered sedation. He
improved slowly and by 6 weeks was
well enough to go on holiday.
After 5 months he was referred to a
psychogeriatrician who recorded that
he had episodes of confusion, forgetfulness and got lost when he went out. He
was sleeping a lot and was incontinent
during the day.
One year later he had an uneventful
cystoscopy. That anaesthetic consisted
of propofol, fentanyl, nitrous oxide and
isoflurane. His blood pressure ranged
from 140/80 to 130/70.
Two years later he required residential
care, having deteriorated substantially.
It would seem that his postoperative
confusion and the accentuation of his
symptoms were related to a relatively
hypotensive, prolonged anaesthetic. This
might have been avoided by proper preoperative evaluation, including consideration of his previous anaesthetics
without complications. Whether the
incident contributed to the progress of
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his Alzheimer's disease is problematic. It
would be valuable to hear of any other
accounts of anaesthesia in patients who
subsequently were found to have developed Alzheimer's disease, as if confirmed, this could well lead to an
important case-controlled study.
I. Bone
Southern General Hospital,
Glasgow G51 4TF, UK
M. Rosen
45 Hollybush Rd,
Cardiff CF23 6TZ, UK
References
1 O'Meara EA, Kikull WA, Sheppard L,
et al. Head injury and the risk of
Alzheimer's disease by Apolipo protein
E genotype. American Journal of
Epidemiology 1997; 146: 373±84.
2 Nicholl JA, Roberts GW, Graham DI.
Amyloid beta protein, APOE genotype
and head injury. Annals of the New York
Academy of Sciences 1996; 777: 271±5.
3 Graham DI, Horburgh K, Nicholl JA,
Teasdale GM. Apolipoprotein E and the
response of the brain to injury. Acta
Neurochirurgica ± Supplementum 1999;
73: 89±92.
Forgotten already?
Our good friend Tom Boulton, a past
president of both the Association of
Dental Anaesthetists and the Society for
the Advancement of Anaesthesia in
Dentistry as well as the Association of
Anaesthetists of Great Britain and Ireland, omits one word in his excellent
Editorial (Anaesthesia 1999; 54: 823±5)
± dentists.
We refer in particular to the phrase
`that the administration of anaesthesia in
the British sphere of influence has had
the advantage of remaining exclusively
in the hands of medically qualified
practitioners.' Perhaps in reflecting on
the history of anaesthesia we might also
consider the part played by dentists.
The earliest use of general anaesthesia
was for dental procedures. Horace Wells
was a dentist as were Morton and
Robinson, the last being credited with
q 2000 Blackwell Science Ltd
the first use of general anaesthesia in the
UK. In Britain more general anaesthetics were given for dentistry than for
any other procedure: in the last 50 years
more than 20 million, and most of these
were administered by dentists. It has
been fashionable in recent years to
deride this contribution and service by
our profession but the fact remains that
millions of patients benefited from it.
One must also remember that the safety
record of chair-side anaesthesia was not
related to the class of administrator be
they general dental practitioner, general
medical practitioner or specialist anaesthetist. At the close of the 20th century
we dentists voluntarily passed this service
to the speciality of anaesthesia [1].
Dentists should not only look back
proudly on their contribution to general
anaesthesia and the enormous service
they have provided their patients over
the last century and a half but they
should also be remembered for it.
I. Brett
A. Wraith
Society for the Advancement of
Anaesthesia in Dentistry,
London W1M 7DF, UK
Reference
1 General Dental Council. Maintaining
Standards. Guidance to Dentists on
Professional and Personal Conduct.
London: General Dental Council,
1998.
A reply
I regret now that I did not add the
words `and of dental surgeons in their
own practices' to the phrase which Ian
Brett and Andrea Wraith quote from
my Editorial in the September 1999
issue of Anaesthesia (1999; 54 : 823±5).
I consider, however, that the context of
the phrase in my Editorial implied that I
was referring to the administration of
anaesthesia for surgery in general. The
employment of dental surgeons as
anaesthetists for surgical procedures
other than outpatient dentistry has
been extremely rare in British practice,
even under the exigencies of war.
Discussion about priorities in the
history of anaesthesia is, of course, of
great interest, and many authors have
considered the matter exhaustively [1±
4]. My Editorial was not about the
history of anaesthesia per se however; it
was concerned with the development of
the major medical anaesthetic organisations in the United Kingdom [5].
The medical practitioner John Snow
was mentioned in the Editorial because
`it was certainly due to the appreciation
by his contemporaries of Snow's superior
skill, based on scientific investigation, that
the administration of anaesthesia in the
British sphere of influence has had the
advantage of remaining exclusively in
the hands of medically qualified practitioners' and [I accept] dental surgeons in
there own practices [6, 7]. This fact formed
the basis for the later development of the
medicopolitical organisation of anaesthesia in the United Kingdom [5]. The
dentists Wells and Morton gave up the
administration of anaesthesia soon after
their important initial demonstrations of
nitrous oxide and ether anaesthesia and
became involved in an unedifying struggle to establish priority [1±3]. Robinson,
arguably the leading dentist in England in
the 1840s, ceased to administer anaesthetics shortly after publishing the first
textbook on ether anaesthesia in 1847.
This was because he had other major
projects in dentistry to pursue [7]. John
Snow continued to study anaesthesia and
anaesthetised patients for a variety of
surgical procedures from the time of the
introduction of ether anaesthesia in 1846
until his death in 1858 [6±8].
I expended a great deal of effort
during my active career in an endeavour
to reconcile the views of the medical and
dental professions regarding who should
administer anaesthesia for outpatients, as
well as how, why and when they should
do so. Extremists of both professions
have sometimes made immoderate or
prejudiced assertions. I have recently
tried to present fairly and chronologically
the various issues that have arisen during
the last three-quarters of a century [5].
The standards of practice justifiably
accepted in the middle of the 20th
century are obviously not those that are
acceptable in the 21st century however.
Time has moved on.
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Anaesthesia, 2000, 55, pages 590±619
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The admirable record of dental
surgeons who devoted time and effort
to improving both expertise and safety
in the practice of outpatient anaesthesia
in their own practices should certainly
not be forgotten. Dental surgeons have
also made major contributions to the
development of sedation techniques in
recent decades [5]. I predicted in 1980,
in my Presidential Address to the
Society for the Advancement of Anaesthesia in Dentistry (SAAD), that `full
general anaesthesia ``in the chair'' will
give way to psychological and pharmacological techniques of analgesia and
sedation short of full general anaesthesia' [9]. This suggestion was unpopular
with some of my audience at the time,
but I consider that it has proved to be
justified.
T. B. Boulton
Honorary Consultant Anaesthetist,
Oxford & Reading Hospitals, UK
References
1 Duncum BM. The Development of
Inhalation Anaesthesia. London: Oxford
University Press, 1947.
2 Boulton TB, Wilkinson DJ. The
origins of modern anaesthesia. In:
Healy TJ, Cohen PJ, eds. Wylie and
Churchill Davidson's a Practice of
Anaesthesia. London: Edward Arnold,
1995: 3±35.
3 Rushman GB, Davies NJH, Atkinson
RS. A Short History of Anaesthesia.
Oxford: Butterworth-Heinemann,
1996.
4 Bergman NA. The Genesis of Surgical
Anaesthesia. Park Ridge: Wood LibraryMuseum of Anesthesiology, 1998.
5 Boulton TB. The Association of
Anaesthetists of Great Britain and Ireland
and the Development of the Specialty of
Anaesthesia, 1932±92. London:
Association of Anaesthetists of Great
Britain and Ireland, 1989.
6 Ellis RH, ed. The Case Books of John
Snow. Medical History Supplement 14.
London: Wellcome Institute for the
History of Medicine, 1994.
7 Ellis RH, ed. James Robinson on the
Inhalation of the Vapour of Ether.
Eastbourne: Boiler Tindall, 1983.
594
8 Snow J. Chloroform and Other
Anaesthetics. London: Churchill, 1858.
9 Boulton TB. Presidential address: The
rise and fall of general anaesthesia in the
dental chair. SAAD Digest 1980; 4:
156±65.
The anaesthetic team
I read with great interest Dr Morgan's
Editorial (Anaesthesia 2000; 55: 1±3)
concerning his examination of anaesthesia development, and would like to
take up two points.
Firstly, what does Dr Morgan mean by
the phrase ± `We have been fortunate in
this country in that anaesthesia has been
a physician-only speciality'? Fortunate
for whom? The patient or the doctor? I
presume that Dr Morgan is making a
reference to the issue of the nonphysician
anaesthetist that is common with our
North American and European colleagues. This issue has been debated for a
number of years in the UK, and there has
been recent agreement by Medical and
Nursing organisations that this would do
little to solve the anaesthetic manpower
crisis or help develop the provision of
anaesthesia in the NHS [1±2]. One
hopes that this issue is now finally laid
to rest. However, there are valuable
lessons that can be learnt from the US
and European approach to anaesthesia,
specifically in the development of the
anaesthetic team. It is not uncommon in
the US for a team of an Anaesthesiologist, Nurse Anaesthetist and Assistant to
utilise a case management approach for
the peri-anaesthetic period. A hybrid of
this model transferred into the UK
context could improve patient care, and
develop and foster collaborative working
practices with greater professional understanding. If in the UK an anaesthetist,
anaesthetic nurse and recovery nurse
were to jointly consider the plan of
care for a patient undergoing surgery it
would go a long way to providing a total
peri-anaesthetic care package. The added
benefits of this would reduce risks
associated with communication errors,
and provide seamless continuity from
admission to discharge.
My second point is one of addition to
Dr Morgan's historical review. One can
only concur with the sentiments that the
technological advancement in anaesthesia has indeed reduced morbidity and
mortality considerably. This has led to
the position today where it is thankfully
rare for unexpected intra-operative complications to occur. However, despite
these changes the postoperative period
still frequently presents challenges to the
medical and nursing staff. Indeed, the
importance of effective and skilled
recovery was highlighted within the
first two decades of `modern anaesthesia'
in 1846. From Flemings' original idea in
1923 at the Medical Institute of Birmingham, the concept of an integral
recovery unit has been reinforced continually since [3]. It has been suggested
that it is the development of recovery
units that have proven most effective in
reducing deaths from anaesthesia in the
last 150 years [4]. I believe that the RCA
use the availability of the post anaesthetic
recovery units as a benchmark for
accessing a hospital's suitability for training of junior anaesthetists.
M. Radford
Vice Chairman & Editor,
British Anaesthetic & Recovery
Nurses Association,
Sutton Coldfield B76 1RQ, UK
References
1 Reilly C, Challands A, Barrett A, Reid
S. Professional Roles in Anaesthesia: a
Scoping Study. Leeds: NHS Executive,
1996.
2 Radford M. Nurse anaesthetists: a job
too far? British Journal of Nursing 1999;
8: 14.
3 Anon. Report: National Confidential
Enquiry into Perioperative Deaths.
London: 1990.
4 Carrie L, Simpson P, Popat M.
Understanding Anaesthesia, 3rd edn.
London: Butterworth Heinemann, 1996.
Postoperative nausea and
vomiting following 8%
sevoflurane anaesthesia
We read with interest recent correspondence concerning postoperative nausea
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and vomiting (PONV) following 8%
sevoflurane anaesthesia (Anaesthesia
2000; 55: 189±91). Various explanations were proposed for the observed
increase in PONV including the administration of supplemental opioids, and/
or a dose-related sevoflurane effect.
There is little evidence, if any, to
support the latter.
In their paper, Dashfield and colleagues use high concentrations of sevoflurane yet report an extremely low
incidence of nausea (10%) [1]. It is
important to note that Dashfield and
colleagues used a nonrebreathing system
in their study and thus did not expose
the sevoflurane to soda lime. Conversely, Smith and Thwaites used low-flow
anaesthesia with CO2 absorption and
reported an incidence of 30% [2]. In a
study similar to that of Dashfield and
co-workers, Philip reports that following sevoflurane induction and maintenance, 78% of patients experienced
some nausea. This study maintained
anaesthesia using sevoflurane at low
fresh gas flows (2 l.min21). No opioids
were administered [3]. Fredman and coworkers also report an extremely high
incidence of nausea (56%) following a
lower dose of sevoflurane for induction
of anaesthesia and maintenance of
anaesthesia using low fresh gas flows [4].
We propose an additional cause of
PONV following sevoflurane anaesthesia. It is known that sevoflurane can be
degraded to formaldehyde when passed
through partially exhausted soda lime
[5]. Rather than the absolute dose of
sevoflurane delivered, an additional
factor in PONV may be the administration of sevoflurane through a
rebreathing system that contains a
strong alkali. Inhalation of formaldehyde, even in minute quantities, will
provoke significant nausea and vomiting
often for up to 48 h [6]. We believe that
when examining the occurrence of
nausea following sevoflurane anaesthesia, it is of fundamental importance to
know whether or not sevoflurane has
been delivered using a rebreathing
system.
Our own work (in progress) shows
that formaldehyde concentrations of
four times the MEL (maximum exposure limit) are readily achieved in vitro by
q 2000 Blackwell Science Ltd
simply passing 6±8% sevoflurane over
dry soda lime. As a result, we would
suggest that degradation of sevoflurane
to formaldehyde by CO2 absorbents
that contain either KOH or NaOH be
considered as an additional factor contributing to PONV after sevoflurane
anaesthesia.
A. Bedi
A. Gallagher
J. P. H. Fee
J. M. Murray
The Queen's University of Belfast,
Belfast BT9 7BL, UK
References
1 Dashfield AK, Birt DJ, Thurlow J,
Kestin IG, Langton JA. Recovery
characteristics using single-breath 8%
sevoflurane or propofol for induction of
anaesthesia in day-case arthroscopy
patients. Anaesthesia 1998; 53: 1062±6.
2 Smith I, Thwaites AJ. Target-controlled
propofol vs. sevoflurane: a doubleblind, randomised comparison in daycase anaesthesia. Anaesthesia 1999; 54:
745±52.
3 Philip BK, Lombard LL, Roaf ER,
Drager LR, Calalang I, Philip JH.
Comparison of vital capacity induction
with sevoflurane to intravenous
induction with propofol for adult
ambulatory anesthesia. Anesthesia and
Analgesia 1999; 89: 623.
4 Fredman B, Nathanson MH, Smith I,
Wang J, Klein K, White PF. Sevoflurane
for outpatient anesthesia: a comparison
with propofol. Anesthesia and Analgesia
1995; 81: 823±8.
5 Funk W, Gruber M, Wild K,
Hobbhahn J. Dry soda lime markedly
degrades sevoflurane during simulated
inhalational induction. British Journal of
Anaesthesia 1999; 82: 193±8.
6 United States Environmental
Protection Agency-Formaldehyde.
http://www.epa.gov/iedweb00/
formalde.html.
Unexpected difficult intubation
caused by subglottic ring
We wish to report a case of unexpected
difficult intubation after induction of
anaesthesia caused by a tracheal ring.
A 58-year-old woman, ASA III, was
admitted for hysterectomy and bilateral
salpingo-oophorectomy because of
endometrial adenocarcinoma. Medical
history revealed morbid obesity, noninsulin-dependent diabetes mellitus,
hypertension and chronic asthmatic
bronchitis treated with b2-adrenergic
agonists, methylxanthines and oxygen
therapy.
Pulmonary function testing revealed
an FEV1 of 38%, arterial blood gases
confirmed
hypoxaemia
(Pao2
51 mmHg) and slight hypercapnia
(Paco2 43 mmHg). Past surgical history included a laparotomy under general anaesthesia requiring some days in
ICU because of her morbid obesity.
Difficulty of tracheal intubation was
suspected because of obesity and inadequate neck extension; after topical
anaesthesia, vocal cords were clearly
seen at laryngoscopy. General anaesthesia was induced and vecuronium 12 mg
was given to facilitate tracheal intubation. A 7.5-mm i.d. tracheal tube could
not be advanced beyond the vocal cords
because of resistance. Intubation was
reattempted with smaller tubes; finally, a
5.0-mm i.d. tube was passed through
the vocal cords but adequate ventilation
could not be maintained. The patient's
trachea was extubated and normal
emergence from anaesthesia occurred.
Because of the unexpected difficulties in
intubation an otolaryngologist was consulted in the operating theatre to
examine the larynx and trachea. A
tracheal ring was found which caused
subglottic stenosis. Because of morbid
obesity the patient was observed overnight in ICU.
In the following days, following
tracheostomy under local anaesthesia,
general anaesthesia was induced and
laser airway surgery was performed.
Her tracheostomy was maintained to
allow a hysterectomy and bilateral
salpingo-oophorectomy to be carried
out. Some weeks later the tracheostomy
tube was removed, her flow volume
loop improved and oxygen therapy was
discontinued.
Our case of difficult intubation was
unexpected even though a difficult
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Anaesthesia, 2000, 55, pages 590±619
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laryngoscopy was anticipated for
morbid obesity and inadequate neck
extension; after induction of general
anaesthesia, a tracheal ring created an
obstacle to tracheal intubation and only
a very small tracheal tube could be
passed (5.0-mm i.d. tube), which
proved inadequate for ventilation. A
tracheal ring consists of a congenital or
acquired, fibrous membrane. An acquired
ring may develop as a result of injury to
the tracheal mucous membrane and
submucosal tissues primarily due to
iatrogenic intervention, especially longterm intubation [1±3].
Postoperative review of the patient's
history revealed worsening of dyspnoea
following her previous laparotomy. Her
postoperative period of ventilation in
ICU for morbid obesity probably
caused scaring, which resulted in an
acquired tracheal ring. However, her
increasing tracheal stenosis was confused
with worsening of chronic bronchitis.
In this case a tracheal ring was an
unsuspected and coincidental finding
but caused an obstacle to tracheal
intubation [1±3].
The absence of symptoms such as
stridor or sign of upper airways obstruction, in spite of a marked decrease in
tracheal cross-section, is consistent with
the observation that symptoms rarely
occur until at least 75% of the tracheal
diameter has been obliterated [3]; in this
case exertional dyspnoea was attributed
to worsening of chronic bronchitis.
caused by a laryngeal web. British Journal
of Anaesthesia 1997; 79: 396±7.
3 Baron SH, Kohlmoos HW. Laryngeal
sequelae of endotracheal intubation.
Anesthesia and Analgesia 1975; 54: 767±
72.
Airway Management Device
(AMDTM) for airway control in
percutaneous dilatational
tracheostomy
Since the first description of the technique in 1985 [1], percutaneous dilatational tracheostomy has developed into a
bedside procedure on the Intensive Care
Unit. Experience has shown that airway
control in the intubated patient during
tracheostomy has been fraught with
difficulties. These include accidental
extubation, transfixion of the tracheal
tube by the introducing needle and
cannula, and deflation of the cuff from
inadvertent puncture by the needle [2].
Needle damage to flexible bronchoscopes used for tracheal visualisation of
the procedure can also occur. We
describe the use of a new airway adjunct,
which may overcome these problems.
The Airway Management Device
(AMDe) (Biosil Ltd, Cumbernauld,
UK) is a hollow, clear, silicone rubber
tube with two inflatable cuffs along its
length (Fig. 1). The tapered distal cuff
sits at the end of the tube and, when
inflated with 6±10 ml of air, occludes a
small central lumen. When the AMD is
inserted with the distal cuff inflated it
lodges into the upper oesophagus.
Deflation of the cuff after placement
allows passage of a suction catheter into
the oesophagus to clear secretions. The
proximal cuff sits at the level of the
pharynx and is inflated with a variable
volume of air such as to occlude the
pharynx and prevent gas leakage during
ventilation. Between the two cuffs is a
short length of exposed tube with an
anterior-facing elliptical hole, and when
the AMD is correctly sited this hole
faces onto the laryngeal inlet. Ventilation is via the integral 15-mm rightangled swivel-mount on the top of the
A. Ceron
V. Ambroselli
C. Zannoni
Circolo Hospital,
Varese, Italy
D. Bertollo
via Matteotti 9,
21045 Gazzada (VA), Italy
References
1 Capistrano-Baruh E, Wenig B,
Steinberg L, Stegnjajjc A, Baruh S.
Laryngeal web: a cause of difficult
endotracheal intubation. Anesthesiology
1982; 57: 123±5.
2 Chong Z-K, Jawan B, Poon Y-Y, Lee JH. Unsuspected difficult intubation
596
Figure 1
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Anaesthesia, 2000, 55, pages 590±619
Correspondence
................................................................................................................................................................................................................................................
tube. Suction catheters can be inserted
via the silicon stopper on top of the
mount.
The AMD was used during tracheostomy in an 83-year-old male
ventilated on our Intensive Care Unit.
He was recovering from emergency
repair of ruptured abdominal aortic
aneurysm, compounded by haemodynamic instability from poor myocardial
function. The decision to perform
tracheostomy was made on day 5 to
facilitate anticipated longer-term ventilation and weaning. Following paralysis
and increased sedation, the patient had
his 9.0 oral tracheal tube removed and a
size 3±3.5 AMD inserted with 8 ml air
in the lower cuff. A volume of 50 ml air
was used to inflate the upper cuff and
ventilation continued with 100% O2.
Gas leakage occurred around the upper
cuff and a further 10 ml of air was
introduced with some reduction in leak.
Inflation of the lungs was satisfactory
and the patient was positioned with
extended neck prior to tracheostomy.
No increase in leak occurred but it was
noted that the tongue was becoming
congested. We had previously noted this
phenomenon during use of the AMD in
general anaesthesia. It was not improved
by adjusting the position of the AMD.
Our Intensive Care Unit's normal
practice is to perform percutaneous
tracheostomy under bronchoscopic
control, and so an Olympus 5.2-mm
flexible bronchoscope was inserted
through the swivel-mount, which
maintained a gas-tight seal, and was
passed in to the upper trachea with
some difficulty. This was because the
epiglottis had been pushed down on to
the orifice of the AMD and the glottic
opening was deviated to the right.
Percutaneous dilatational tracheostomy using the Ciaglia kit (Cook Critical
Care) was performed in the usual
manner and an 8.0 Tracheosoft
PERCe (Mallinckrodt Medical) tracheostomy tube with adjustable flange
inserted. Correct placement and adjustment of the tube was made using the
flexible bronchoscope, and mechanical
ventilation recommenced. At the end of
the procedure it was noted that the
tongue was much more congested,
enlarged and had a bluish colour. This
q 2000 Blackwell Science Ltd
quickly resolved on deflation and
removal of the AMD. No oropharyngeal
trauma was noted and no regurgitation
or aspiration of gastric contents was seen.
The whole procedure took 30 min.
Use of the AMD facilitated percutaneous tracheostomy in this patient, but
was not without its problems. Repositioning could not reduce glottic congestion and, although it quickly
resolved on AMD removal, we do
voice concerns over possible lingual
nerve damage with prolonged use,
similar to that which has been described
with use of the laryngeal mask airway
[3]. Use of the larger size AMD, size 4±
5, may have overcome this problem.
We feel that the AMD may have a
useful role in airway management during
percutaneous tracheostomy, particularly as
it overcomes the problems with having a
tracheal tube in situ, and we are undertaking a further study to assess its clinical
potential in the critical care setting.
R. Johnson
R. Bailie
Royal Halifax Infirmary,
Halifax HX1 2YP, UK
References
1 Ciagla P, Firsching R, Syniec C.
Elective percutaneous dilatational
tracheostomy: a new simple bedside
procedure: preliminary report. Chest
1985; 87: 715±9.
2 Thomas EO, Manara AR. A review of
percutaneous tracheostomy. British
Journal of Intensive Care 1998; 8: 122±9.
3 Majumder S, Hopkins PM. Bilateral
lingual nerve injury following the use
of the laryngeal mask airway. Anaesthesia
1998; 53: 184±6.
Complications following the use
of the Combitube, tracheal tube
and laryngeal mask airway
We wish to comment on the article by
Oczenski et al. (Anaesthesia 1999;
54: 1161±5) describing a higher rate
of complications with the use of the
Combitube 37 F SA (CT) than with the
other two devices.
The authors describe that in the CT
group of 25 patients the device was
electively inserted with difficulty in 13
patients (52%), two patients required
two attempts and one patient required
three attempts. With this grade of
difficulty, they reported an incidence
of 48% sore throat, of 68% dysphagia,
which were severe and long lasting
(. 24 h) in eight patients (32%), and
the presence of haematoma in 36%.
These findings are opposite to our
results in 25 patients using the same
model of CT inserted under direct
laryngoscopy [1], in which no severe
complication could be observed.
Oczenski's results are also opposite to
the low rate of complications reported
in the literature using the larger size 41
F, inserted by technicians and in emergency prehospital situations [2, 3]. We
were surprised that the four experienced participant anaesthetists obtained
such a high rate of complications in
performing an elective procedure,
including the occurrence of haematoma
in 4% of both the LMA and the ET
group and an 8% failure rate in the
insertion of the LMA, which also
contrasts with the published experience
[4]. We think that this high rate of
complications suggests that the procedures were traumatic, probably due to
an inappropriate insertion technique or
insufficient operator skill. Although the
CT design allows blind insertion, the
manufacturer [5] recommends using a
laryngoscope in order to avoid complications derived from a blind procedure.
On the other hand, 60% nitrous
oxide could over-inflate the cuffs over
time, which may induce mucosal injury
[6, 7]. Thus, we think that the reason
given by the authors to explain the
higher incidence of postoperative complications could be overestimated by this
factor. In addition, we consider that the
conclusion that the CT cannot be
recommended for routine airway management is not acceptable. Such a
conclusion, with regard to safety,
cannot be stated from data on only 25
patients. Finally, since the CT is a device
often used in the emergency airway
management, its use for routine airway
management is advisable, especially in
residency programmes [8]. With routine
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Anaesthesia, 2000, 55, pages 590±619
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use the operator will gain experience
and will avoid seeing it for the first time
during efforts to ventilate a `failed
intubation'.
R. M. Urtubia
C. R. CaÂrcamo
J. M. Montes
Mutual de Seguridad Hospital
C.CH.C,
Santiago, Chile
References
1 Urtubia RM, Aguila CM, Cumsille
MA. Combitube. A study for proper
use. Anesthesia and Analgesia 2000; 90:
958±62.
2 Tanigawa K, Shigematsu A. Choice of
airway devices for 12,020 cases of non±
traumatic cardiac arrest in Japan.
Prehospital Emergency Care 1998; 2: 96±
100.
3 Rumball CJ, MacDonald D. The PTL,
Combitube, laryngeal mask airway, and
oral airway: a randomized prehospital
comparative study of ventilatory device
effectiveness and cost-effectiveness in
470 cases of cardiorespiratory arrest.
Prehospital Emergency Care 1997; 1: 1±
10.
4 Verghese C, Brimacombe JR. Survey of
the laryngeal mask airway usage in
11,910 patients: safety and efficacy for
conventional and nonconventional
usage. Anesthesia and Analgesia 1996; 82:
129±33.
5 Frass M. The Combitube: Esophageal/
Tracheal double-lumen airway. In:
Benumof JL, ed. Airway Management ±
Principles and Practice. Mosby-Year
Book, Inc., 1996: 444±54.
6 Brimacombe J, Berry A. Laryngeal
mask airway cuff pressure and position
during anaesthesia lasting one to two
hours. Canadian Journal of Anaesthesia
1994; 41: 589±93.
7 Tu HN, Saidi N, Lieutaud T, Bensaid S,
Menival V, Duvaldestin P. Nitrous
oxide increases endotracheal cuff
pressure and the incidence of tracheal
lesions in anesthetized patients.
Anesthesia and Analgesia 1999; 89: 187±
90.
8 Koppel JN, Reed AP. Formal
instruction in difficult airway
management. A survey of
598
Table 2
Combitube
Failed insertion (%)
Successful ventilation (%)
LMA
Failed insertion (%)
Successful ventilation (%)
Tanigawa
et al.
Rumball
et al.
Oczenski
et al.
6.9
78.9
86
0
100
10.5
71.5
73
8
92
anesthesiology residency programs.
Anesthesiology 1995; 83: 1343±6.
A reply
Thank you for allowing us to respond to
the letter from Dr Urtubia and coworkers. We feel it is necessary to clarify
some points mentioned in their letter.
1 The authors of the letter report a
much lower incidence of complications
in 25 patients where a Combitube was
inserted with the help of a laryngoscope. We congratulate the authors on
these results. However, the comparability of their results with ours is limited as
our conclusion precisely refers to `blind
insertion of the Combitube'.
2 The authors state that others have
described much lower rates of complications: the first publication by Tanigawa
et al. [1] describes results from a survey in
nontraumatic emergency patients and
evaluated three devices for securing the
airway including the Combitube and the
laryngeal mask airway (LMA). The
second publication by Rumball et al.
[2] compares several devices, also including the Combitube and the LMA. We
have to point out that the scoring system
for difficult intubation/insertion used in
our study was subjective and served the
goal of allowing a correlation when
trauma was detected in a patient or a
patient reported discomfort on the
follow-up. With this scoring system we
classified insertion conditions into excellent, good, poor and impossible. According to this classification, 84% of
insertions of the Combitube and 92%
of LMA insertions were graded as
excellent and good.
Data presented in the two studies
refer to failed and successful insertion
and ventilation of the tested devices.
Only the percentage of successful and
failed insertion is reported, without any
grading. In both publications these
numbers were substantially worse than
in our investigation.
The numbers of successful placements of the Combitube and the LMA
in the two studies compared with ours
are shown in the Table 2.
We point out that the number of cases
in our study is much smaller than in the
two others, but certainly our data are not
worse than those reported in the literature. Again, the goal of our study was to
report on complications following the
use of the Combitube, tracheal tube and
LMA, and not insertion conditions.
However, we do not accept that the
results we reported are due to `inappropriate insertion technique or insufficient operator skills'. Furthermore, we
had the advantage that Dr Frass is
working in Vienna, and he trained us
in the correct use of the device.
The authors of the letter furthermore
state that the rate of complications in our
study is much higher than in the studies
named above. In contrast to the studies
named by the authors of the letter, we
prospectively investigated the traumatic
effects of the devices by having the
patients inspected by an otolaryngologist
before and after the use of the devices.
Furthermore, Tanigawa et al. recognised
that their study probably underestimated
the incidence of complications [1].
We believe that our protocol was not
biased by such difficulties and our data
are valid.
3 Blind insertion vs. manufacturer
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................................................................................................................................................................................................................................................
recommendations: the authors of the
letter refer to a review written by Dr
Frass [3], who is not the manufacturer,
but the inventor of this device. Although
he is closely co-operating with the
manufacturer, this textbook chapter is
not part of the manufacturer's recommendation. The guidelines that are
packed and sold with the device state
that `the use of a laryngoscope is not
necessary, although it might be helpful'
(translated from German into English by
the authors). Dr Frass was aware of our
protocol, and did not advise us to change
the method from blind insertion to
laryngoscope-guided insertion. This is
understandable as it is the main feature
and advantage of this device to allow
blind insertion and not to require the use
of a laryngoscope. Even in the textbook
chapter cited by the authors of the letter
[3], Dr Frass recommends the use of the
laryngoscope for situations where intubation with direct laryngoscopy fails and
the laryngoscope is still in place. Thus,
despite the fact that we recognise the use
of the laryngoscope as an interesting
alternative and possible improvement of
the method (although a main advantage is
lost), we believe that utilising blind
insertion of the Combitube in our
study is the valid choice and has to be
chosen when evaluated against other
devices and methods.
4 The authors suggest that the pressure
effects of the cuffs reported in our study
could be worsened by over inflation of
the cuffs with nitrous oxide. This indeed
is relevant, and we regret not reporting
our handling of this problem in our
manuscript. It is standard procedure
during every anaesthetic in our Department to monitor cuff pressure on-line.
However, whereas pressure values for
tracheal tubes are well known, no such
values exist for LMA and Combitube.
Thus, our procedure consisted of inflating the cuffs of the Combitube with the
recommended volume of air and taking
the (very variable) pressure value as
baseline for correction of the nitrous
oxide effect. With the LMA the cuff was
inflated to allow an optimal sealing of the
larynx and again this value was taken as
baseline for correcting overinflation.
This method is very simple and does
not exclude that overinflation of the cuffs
q 2000 Blackwell Science Ltd
is responsible for some of the traumatising effects seen in our study. However, as
long as no optimal values for cuff
pressure for LMA and Combitube are
available, we regretfully have to accept
this possible bias.
5 Invalid conclusion: as described above,
we believe that the participating anaesthetists were sufficiently trained to allow
valid evaluation of the compared devices.
Furthermore, this leads to the question
of how much experience is sufficient for
safe use. Can we regard a device as safe,
when during a possibly long training
period harm is done to patients? While
we do not want to diminish the
importance of the Combitube for emergency settings and recognise the need for
training programmes to avoid `seeing the
device for the first time during efforts to
ventilate a failed intubation', we believe
that our conclusion is valid.
W. Oczenski
R. D. Fitzgerald
City of Vienna Hospital Lainz,
Wolkersbergenstraûe 1,
A-1130 Vienna, Austria
References
1 Tanigawa K, Shigematsu A. Choice of
airway devices for 12,020 cases of
nontraumtic cardiac arrest in Japan.
Prehospital Emergency Care 1998; 2: 96±
100.
2 Rumball CJ, MacDonald D. The PLT,
Combitube, laryngeal mask airway, and
oral airway: a randomised prehospital
comparative study of ventilatory device
effectiveness and cost-effectiveness in
470 cases of cardiorespiratory arrest.
Prehospital Emergency Care 1997; 1: 1±10.
3 Frass M. The Combitube: Esophageal/
Tracheal double-lumen airway. In:
Benumof JL. eds. Airway Management ±
Principles and Practice. Mosby-Year Book
Inc., 1996, Chapter 22:444±54.
Nasendoscopy: a useful
addition to the anaesthetist's
armamentarium
The recent cogently argued editorial by
Mason and Fielder entitled `The
obstructed airway in head and neck
surgery' (Anaesthesia 1999; 54: 625±8)
prompts us to write to urge anaesthetists
to include the fibreoptic nasendoscope
in their airway assessment armamentarium. Hitherto, the anaesthetic fraternity
has regarded the nasendoscope as a
surgeon's tool. We discuss below the
potential benefits of pre-operative
nasendoscopic airway assessment by the
anaesthetist.
We have found the nasendoscope to
be particularly useful for pre-operative
airway assessment in patients in whom
the larynx may be completely normal
but inaccessible or difficult to expose
and in those in whom the larynx is
distorted or displaced by a tumour or
other pathology that impedes visualisation. The surgical nasendoscopic assessment of these patients is often carried
out with the patient sitting upright in an
outpatient setting. The nasendoscopic
view of the larynx recorded in the notes
(not always by a consultant surgeon) is
sometimes very different from the
laryngeal landscape that confronts the
anaesthetist. Even in those patients with
no symptoms at rest, merely lying them
supine and inducing anaesthesia may
result in considerable difficulties with
ventilation and/or tracheal intubation.
This is a potential problem with both
supraglottic and pedunculated glottic
tumours. The view obtained with a
2.7-mm, short nasendoscope is infinitely superior to that obtained with a
standard intubating fibrescope and
nasendoscopy carried out pre-operatively in both the upright and supine
positions by an experienced anaesthetist
will yield valuable information that can
be incorporated into the formulation of
a management plan.
It is a relatively easy procedure to
perform and is well tolerated by patients
with minimal topical local anaesthesia to
the nose. It affords a good opportunity
to teach trainees the motor skills and
dexterity needed to wield the intubating
fibrescope outside the more stressful
operating theatre environment.
Capital cost may be an issue in some
departments. Our surgical colleagues
have kindly allowed us to use their
equipment on the wards for the best
part of the last decade. In an ideal world
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both surgeon and anaesthetist would
assess the patient with oro-pharyngolaryngeal pathology together and jointly
decide the airway management plan.
I. R. Appadurai
J. S. Davies
University Hospital of Wales,
Cardiff CF14 4XW, UK
Upper airway obstruction
Bonner and Taylor (Anaesthesia 2000;
55: 290) are mistaken in their statement
that I advocated awake fibreoptic intubation in upper airway obstruction
(Anaesthesia 1999; 54: 1114). I advocated awake intubation under direct
vision using a conventional laryngoscope, a method that served me well in
that part of my career when I was
meeting these cases.
The majority of patients were suffering from postradiation oedema of the
larynx. Usually most of the anatomy was
unrecognizable; however, the epiglottis
remained visible and the airway appeared
as a pinhole with a telltale bubble. I
found that a normal size tracheal tube
would push the oedema aside and enter
the trachea, to my, and the patient's,
relief. The tube opened the patient's
airway, whereas a fibreoptic laryngoscope, if one had been available then,
would have blocked what was left of it.
I can only hope that if I ever have the
misfortune to have upper airway
obstruction, and I lose it, that those
looking after me do not waste time
performing a formal tracheostomy, but
establish an airway quickly via the
cricothyroid route.
T. J. Hawkins
Willoughby on the Wolds, LE12 6SY,
UK
The `correct' application of
cricoid pressure
The recent papers in Anaesthesia questioning the use of 44 N force as a standard
pressure over the cricoid region during
rapid sequence induction raise some
interesting points (Anaesthesia 2000; 55:
208±11 and 55: 263±8). Both groups of
workers attempted to standardise head
600
position on one pillow. It has been
demonstrated elsewhere that head and
neck position can alter airway anatomy
[1], so presumably the force required to
exert `successful' cricoid pressure will vary
depending on how the head is positioned
at intubation. Many of our emergency
intubations take place outside the operating theatre in less than ideal conditions
and with a variety of head positions [2].
Most cricoid pressure is performed by
anaesthetic assistants and as such can be
variable in its efficacy. The regular testing
of the pressure applied by these assistants
beyond their training is not carried out
routinely. The ability of the assistant to act
effectively in emergency situations, such
as failed intubation, can be crucial in
contributing to a successful outcome [3].
Much work has been done recently
with the training of unskilled personnel
to insert the laryngeal mask airway
(LMA) in emergency situations and
even to intubate through these devices
[4]. However, the problems with aspiration in emergency situations have also
received attention and the use of the
LMA questioned [5]. Given the knowledge that incorrectly applied cricoid
pressure can cause airway occlusion and
deformity and that estimates of the force
required are dependent on the experience of the anaesthetist and assistant,
should there not be some regular review
of procedures in this very routine, yet
crucial area of anaesthetic practice?
P. J. Shirley
Aberdeen Royal Infirmary,
Aberdeen AB25 2ZN, UK
References
1 Buckham M, Brooker M, Brimacombe
J, Keller C. A comparison of the
reinforced and standard laryngeal mask
airway: ease of insertion and the
influence of head and neck position on
oropharyngeal leak pressure and
intracuff pressure. Anaesthesia and
Intensive Care 1999; 27: 628±31.
2 Birkinshaw R, McKinnon KA,
Kitching G, Ryan B. Intubation in
difficult positions. Pre-Hospital
Immediate Care 1998; 2: 59±62.
3 Kluger MT, Bukofzer M, Bullock M.
Anaesthetic assistants: their role in the
development and resolution of
anaesthetic incidents. Anaesthesia and
Intensive Care 1999; 27: 269±74.
4 Choyce A, Avidan MS, Patel C et al.
Comparison of laryngeal mask and
intubating laryngeal mask insertion by
the naõÈve intubator. British Journal of
Anaesthesia 2000; 84: 103±5.
5 Lockey DJ, Coats T, Parr MJA.
Aspiration in severe trauma: a prospective
study. Anaesthesia 1999; 54: 1097±109.
Tranexamic acid applied
topically to achieve
haemostasis
Tranexamic acid is an antifibrinolytic
agent that may be administered orally or
by intravenous injection to reduce
bleeding following procedures such as
prostatectomy and dental extraction.
Use of this agent is, however, contraindicated in patients with a history of
thromboembolic disease. We report a
case in which tranexamic acid was used
topically to stop bleeding in a patient in
whom such a contraindication prevented its intravenous use.
A 75-year-old male patient presented
for excision of a large left-sided parotid
pleomorphic adenoma. His past medical
history included hypertension, a gait
and balance disorder (believed to be a
variant of Parkinson's disease) and
transient ischaemic attacks. As a result
of the latter he was prescribed aspirin
75 mg and dipyridamole 25 mg daily.
One hour after an uneventful excision
of the tumour, bleeding and swelling
around the neck and face were noted and
re-exploration was required. Following
an awake fibreoptic intubation, general
anaesthesia was re-established and surgical exploration revealed brisk oozing that
persisted despite diathermy. The use of
intravenous tranexamic acid (Cyclokapron) was considered but because of the
patient's history of thromboembolic disease we decided instead to soak gauze
swabs with 1000 mg of this agent and
apply it directly into the wound. Following this manoeuvre, bleeding ceased and
there were no further complications.
We have been unable to find any other
reports describing the topical use of
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tranexamic acid as a means of treating
intra-operative haemorrhage. There are,
however, reports confirming effective
topical application when combined
with another haemostatic agent (carbazochrome sodium sulphonate) to reduce
bleeding following total knee arthroplasty [1] and also as an enema to stop
rectal bleeding [2]. The prompt response
to direct application of the drug in our
patient suggests a beneficial local effect
but we were unable to measure the
plasma level to determine the degree of
systemic absorption. There is, however,
one study (in rabbits) that compares
systemic levels of tranexamic acid following topical and intravenous administration [3]. This reported significantly
lower serum concentrations following
topical application (to the eye) than after
intravenous administration. We would
therefore suggest that topical administration of tranexamic acid may be of benefit
in reducing bleeding from surgical
wounds and be associated with less risk
of thromboembolism than may occur
with intravenous administration.
N. Coker
D. J. Higgins
Southend Hospital,
Essex SS0 0RY, UK
References
1 Akizuki S, Yasukawa Y, Takizawa T. A
new method of haemostasis for
cementless total knee arthroplasty.
Bulletin ± Hospital for Joint Diseases.
1997; 56: 222±4.
2 McElligott E, Quigley C, Hanks GW.
Tranexamic acid and rectal bleeding.
Lancet 1991; 337: 431.
3 Damji KF, Noel LP, Peterson RG, et al.
Topical versus intravenous
administration of tranexamic acid: a
comparison of intraocular and serum
concentrations in the rabbit. Canadian
Journal of Opthalmology 1998; 33: 308±
13.
Postoperative delirium
mimicking epilepsy
We read with interest the article by
Reuber et al. (Anaesthesia 2000; 55: 74±
q 2000 Blackwell Science Ltd
8) on postoperative pseudostatus. We
think this paper deals with an important
clinical scenario about which little has
been reported so far. We wish to share
our experience in managing a 47-yearold female with a history of long-standing
epilepsy who had pseudoepileptic
seizures due to postoperative delirium.
She had suffered from epilepsy since the
age of 14 years, for which she was
treated with carbamezepine 300 mg qds
and primidone 250 mg qds. Although
her last epileptic fit was 14 years ago, she
suffered status epilepticus following a
decompression of carpal tunnel under
general anaesthesia 9 years ago and an
epileptic fit associated with collapse
following lidocaine and epinephrine
dental injection a year ago. Otherwise,
she had several uncomplicated operations, mainly for congenital lumbar canal
stenosis. During her current admission
for elective laminectomy of the 5th
lumbar vertebra for decompression of
L5 and S1 nerve roots, she was extremely
anxious on pre-operative assessment. She
failed to relax despite 5 mg of midazolam
and 1000 mg of thiopental for induction,
and required isoflurane. Muscle relaxation was induced with succinylcholine
and anaesthesia was maintained with
isoflurane.
Her operative course was uneventful.
However, during recovery she had two
episodes of generalised shaking movements lasting for 3 min each, but not
associated with loss of consciousness,
incontinence or tongue biting. Her
oxygen saturations were maintained
during recovery. She remained confused, drowsy but rousable. In view of
the epileptiform movements she was
intubated and ventilated on the intensive care unit overnight. However, these
abnormal movements, which were
thought to be `atypical' seizures, persisted in the ensuing week despite the
addition of intravenous phenytoin to
her anti-epileptic medication. Her CT
head scan and blood tests were normal.
She also started hallucinating during
abnormal movements. Her EEG, when
she was confused, agitated and exhibiting abnormal movements, showed no
epileptic activity. She was treated for
postoperative delirium with droperidol
5±10 mg qds and her epileptiform
shaking movements stopped. She also
stopped hallucinating and remained well
subsequently.
Delirium during the recovery period
has been mainly reported in elderly
patients [1]. Typical diagnostic criteria
for delirium include perceptual disturbance, incoherent speech, disorientation, memory lapses, and reduced
awareness and attention. Our patient
was at risk of developing postoperative
delirium because of epilepsy, anticonvulsant drugs, previous numerous
operations and anxiety. She suffered
from hallucinations and agitated behaviour associated with abnormal movements, which mimicked epilepsy. She
responded to neuroleptic medication,
droperidol ± the preferred treatment for
delirium. These features suggest that her
agitation and shaking during the postoperative period were not due to
epilepsy.
R. Makker
W. Yanny
Hemel Hempstead General Hospital,
Herts. HP2 4AD, UK
Reference
1 O'Keefe ST, Ni Chonchubhair A.
Postoperative delirium in the elderly.
British Journal of Anaesthesia 1994; 73:
673±87.
An unusual case of
postoperative facial swelling
I wish to report an unusual case of
postoperative facial swelling.
A
24-year-old
Afro-Caribbean
woman with pre-eclampsia underwent
uneventful Caesarean section at
33 weeks gestation for fetal distress.
Anaesthesia was provided by an epidural
previously sited for labour analgesia.
Postoperatively, the patient remained on
the delivery unit for high-dependency
care. The epidural remained in situ to
provide postoperative analgesia, using a
bupivacaine and fentanyl infusion.
The following morning the epidural
was removed and patient-controlled
analgesia (PCA) with morphine was
started. Approximately 50 min later
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Anaesthesia, 2000, 55, pages 590±619
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the patient complained of painful bilateral facial swelling in the region of the
parotid glands. The only `new' drug
introduced to the patient at that time
was morphine, so the PCA was disconnected. The total dose of morphine
given was 8 mg. Thereafter, the swelling rapidly subsided and according to
the patient this was accompanied by an
increased quantity of saliva in her
mouth. At no time was there any sign
of airway obstruction.
Alternative analgesia was provided
with codeine phosphate, paracetamol
and diclofenac. The rest of her postoperative course was unremarkable. She
denied any previous history of parotid
swelling, and this was the first occasion
on which she had ever received
morphine.
Morphine is known to reduce the
secretion of amylase from isolated
parotid acini [1]. However, the ability
of morphine to both increase tone and
decrease propulsive activity of smooth
muscle throughout the gastrointestinal
tract is also well recognised [2±3]. These
latter effects may be mediated via m
receptors. The ducts of the parotid
salivary glands are surrounded by myoepithelial cells. These cells resemble
smooth muscle cells, and by their
contraction they facilitate the movement of glandular secretions [4].
I propose that this patient's facial
swelling may have been caused by
morphine-induced spasm of the parotid
ducts, leading to an accumulation of
saliva in the parotid glands. An extensive
literature search has failed to find any
previous reference to this phenomenon.
J. Kenningham
Withington Hospital,
Manchester M20 2LR, UK
References
1 Miwa Y, Saeki M, Yamaji A, Maeda S,
Saito K. Effect of morphine on
secretion of amylase from isolated
parotid acini. Life Sciences 1996; 59:
1809±19.
2 Vieira ZG, Duarte B, Renigers SA et al.
Double-blind ultrasonographic
demonstration of morphine induced
602
Figure 2 Apparatus used for ambient oxygenation during one-lung ventilation. The
system consists of a 500-ml wide-bore reservoir tubing attached by a T-piece to the
double-lumen tube connector. Oxygen is administered via the side-arm of the T-piece.
spasm of the common bile duct.
Anesthesiology 1988; 69: A347.
3 Aitkenhead AR. Anaesthesia and bowel
surgery. British Journal of Anaesthesia
1984; 56: 95±101.
4 Sicher H, Bhaskar SN. Orban`s Oral
Histology and Embryology, 7th edn. Saint
Louis: CV Mosby, Company 1972;
278.
Ambient pressure oxygenation
via the nonventilated lung
during video-assisted
thoracoscopy
One-lung ventilation (OLV) during
video-assisted thoracoscopy is mandatory in order to ensure collapse of the
lung on the operative side. During OLV
ventilation, opening of the nonventilated lung to the ambient air is usually
established before the chest is opened,
and hence before the nonventilated lung
is collapsed. In the presence of pleural
adhesions, lung collapse may be delayed
even after the pleura is opened. Pfitzner
et al. have experimentally shown that
positive-pressure ventilation of one
lung, while the chest is closed, will
generate transient pressure changes in
the contralateral hemithorax which, in
turn, will generate tidal movement of
air, and therefore nitrogen, out of and
back into the nonventilated lung [1].
Ambient pressure oxygenation to the
nonventilated lung is recommended to
exclude air entrainment, and consequently to enhance lung collapse and
decrease the shunt fraction in the
nonventilated lung [2]. The present
report describes a simple apparatus for
providing ambient pressure oxygenation
in patients undergoing video-assisted
thoracoscopy (Fig. 2).
The technique was used in five adult
patients undergoing thoracoscopy. Following induction of general anaesthesia
and double-lumen intubation, two-lung
ventilation (TLV) was initially used for
15 min. The apparatus was then
attached to the double-lumen connector of the nonventilated lung on the
thoracoscopy side, upon initiation of
contralateral one-lung ventilation, and
before opening the pleura. Oxygen flow
of 10 l.min21 was delivered via the Tpiece. After 15 min of ambient pressure
oxygenation of the nonventilated lung,
the T-piece was disconnected and the
nonventilated lung was left open to
room air. Throughout this procedure,
the patient was ventilated with isoflurane in 100% oxygen. The mean arterial
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................................................................................................................................................................................................................................................
Po2 during contralateral one-lung ventilation was significantly higher when
ambient oxygen was used (307 ^
152 mmHg), as compared with that
achieved when the nonventilated lung
was open to room air (136 ^
63 mmHg).
The results show that adequate oxygenation can be achieved during thoracoscopy when ambient pressure
oxygen is delivered by a T-piece
system attached to the nonventilated
lung before initiation of OLV and prior
to the chest being opened. Ambient
pressure oxygenation should be maintained throughout thoracoscopy. The
technique, as a method of excluding
nitrogen from the nonventilated lung,
may not only improve oxygenation
during OLV, but may also enhance
collapse of the nonventilated lung on
the thoracoscoped side.
A. Baraka
A. Lteif
M. Nawfal
S. Taha
M. Maroun
S. Khoury
M. Jalbout
American University of Beirut
Medical Center,
6044 Beirut, Lebanon
References
1 Pfitzner J, Peacock MJ, McAjeer PT.
Gas movement in the non-ventilated
lung at the onset of single-lung
ventilation for video-assisted
thoracoscopy. Anaesthesia 1999; 54:
431±43.
2 Pfitzner J, Peacock MJ, Daniels BW.
Ambient pressure oxygen reservoir
apparatus for use during one-lung
anaesthesia. Anaesthesia 1999; 54: 454±8.
The effect of pre-emptive
acupuncture treatment on
analgesic requirements after
day-case knee arthroscopy
I read the article by Gupta et al.
(Anaesthesia 1999; 54; 1204±6) with
great interest because there rarely appear
q 2000 Blackwell Science Ltd
articles about acupuncture and its
analgesic effects. The conclusion of the
authors that `acupuncture analgesia has
no additional effect when given under
anaesthesia to patients undergoing knee
arthroscopy' didn't surprise me at all.
The conditions under which the
work was done are contrary to the
long established theory and practice of
acupuncture. The article is a hybrid
between Western medicine and the
Traditional Chinese Medicine (TCM),
which are two different sciences that
should not be mixed up. TCM with its
philosophy has never been Cartesian.
If the study had been directed at, for
example, the postoperative effects of
acupuncture on reduction of oedema
and relieving pain in the first 24 h, the
article would have been much more
useful. They could, for example, perform arthroscopy under acupuncture
analgesia. These are situations where
acupuncture retains its effectiveness
even when much of Chinese philosophical background is discarded.
The fact that acupuncture was administered after induction of general anaesthesia
by itself excludes any effect of acupuncture
because under the conditions of interruption of neurophysiological integrity the
effect of needles is excluded.
The use of needles of 1 inch was
inadequate as the depth of corresponding points is mostly deeper:
Spleen 9 (Yinlingquan, SP 9) is
situated at 1±2 in.
Spleen 10 (Xuehai, SP 10) is situated
at 1±1.5 in.
Stomach 34 (Liangqui, ST 34) is
situated at 1 in.
Stomach 36 (Zusanii, ST 36) is
situated at 1±1.5 in.
Important points like: B 20 (Pishu), B
40 (Weizhong), B 54 (Zhibian), B 60
(Kuniun) and Liv 8 (Ququan) were not
used.
Even if patients were awake, De Qi
sensations would not have been
achieved for certain with needles of 1
in. (De Qi is closely related to the
therapeutic effect), let alone in the
unconscious, anaesthetised patients.
The needles were also inserted without
confirmation that they were inserted at
the correct points. In addition, a constant electrical stimulation was not used.
The distal point of large intestine 4
(Hegu, L1 4) is poorly effective in
curing postoperative knee pain,
though can be very useful in diseases
of head, neck and upper limbs.
In their discussion the authors realised
that `a properly functioning nervous
system may be essential for acupuncture
analgesia to be effective' which leaves me
wondering why they insisted on finishing the work in an anaesthetised patient.
The fact is that acupuncture is effective
in post-traumatic situations and not as
pre-emptive pain treatment after daycase knee arthroscopy
A. Pelimon
HoÃpital ReÂgional Porrentruy,
2900 Porrentruy, Switzerland
A reply
Thank you for the opportunity to reply
to Dr Pelimon's letter; he makes several
points and we would like to reply to
each in turn.
The conditions under which we did
the study were designed, to the best of
our ability, to allow a double-blind
randomised controlled trial. This has
traditionally been very difficult in studies
involving acupuncture because, of course,
the conscious patient is well aware when
he/she has a needle inserted. Although
sham points have been used, there
remains the problem of De Qi sensation,
which would potentially unblind the
subject. We felt that no knowledge at
all of group allocation could arise (as
indeed it did not) if acupuncture was
performed under general anaesthesia.
We would dispute the idea that two
different sciences should not be `mixed
up'; the history of science is littered with
examples of the benefits of adopting ideas
and techniques from disparate disciplines;
we feel instead that such cross-fertilisations are potentially very fruitful
The labour that we invested was used
to look at the levels of pain in the first
24 h postoperatively. Oedema could
also have served as an end point;
however, this would have been complicated because of the variable amount of
leakage of irrigation fluid into the soft
tissues around the knee during the
surgery.
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It seems unlikely that knee arthroscopy
could be performed under acupuncture
alone, if as Dr Pelimon states `the fact is
that acupuncture is effective in posttraumatic situations, and not as preemptive treatment'. It might indeed be
the case that knee arthroscopy can be
performed under acupuncture analgesia,
but we doubt whether our ethics committee would have allowed a trial to
demonstrate it, and we would also
anticipate difficulties in enrolling patients.
We agree that an explanation of our
findings is that `general anaesthesia by itself
excludes any effect of acupuncture, because
under the conditions of interruption of the
neurophysiological integrity the effect of
the needles is excluded' because as we
stated `it may be that a properly functioning
nervous system is necessary for acupuncture analgesia to be effective'.
Turning to the acupuncture points
used: Dr Pelimon suggests that the use
of needles of one inch (2.5 cm) was not
adequate as the depth of the acupoints
used in our study are mostly deeper,
between 1 and 2 inches. The depths of
the acupoints we used in our study are
2±3 cm, LI-4 being just 1±2 cm [1]. In
a study by Christensen et al. [2] on
acupuncture treatment for severe knee
osteoarthritis, they were able to elicit
`Di Qi' sensation at ST-34, ST-36, SP10 and LI-4 at a depth of 1±1.5 cm in
awake patients and had a positive outcome in terms of pain relief.
The important points mentioned by
Dr Pelimon such as B220 (B±bladder),
B240, B254/60, lie on the posterior
aspect of the lower limb. Thus we would
have had to turn the anaesthetised patient
prone to stimulate these points. This
would have necessitated a different
anaesthetic technique involving intubation, and was thought unsuitable. We
agree that a constant electrical stimulation was missing, but this was replaced by
manual stimulation for 5 s every 5 min
and just before needle removal.
LI-4, though a very important point
to treat diseases of head, neck and upper
limbs, is indicated in all forms of pain
treatment and is one of the most
frequently used acupoints for pain.
Most of the studies in the western
literature so far have looked at the antiemetic effect of acupoints P-6 in
604
anaesthetised (general anaesthesia or
local anaesthesia) patients and have
concluded that acupuncture is not
anti-emetic when given under anaesthesia [3]. A study by Chang et al. [4]
concluded that acupuncture analgesia is
abolished when the local anaesthetic
procaine was infiltrated in the deep
tissues around the acupuncture points.
There are no double-blind studies to
prove or disprove the analgesic effect
(rather than anti-emetic effect) of acupuncture treatment when given under
general anaesthesia. A further study
would be needed to assess the possible
analgesic effect of acupuncture at these
(or other) points without prior general
anaesthesia, but it is not clear how such
a study would be blinded adequately to
the patients.
J. M. Sizer
Bedford South Wing Hospital,
Bedford MK42 9DJ, UK
References
1 Stux G. Channels. Organs, and Points.
In: Stux G, Pomeranz B, eds. Basics' of
Acupuncture. London: Springer-Verlag,
1995: 72±187.
2 Christensen BV, Iuhl IU, Vilbek H,
Bulow HH, Dreijer NC, Rasmussen
HF. Acupuncture treatment of severe
knee osteoarthrosis. A long-term study.
Acta Anaesthesiologica Scandinavica 1992;
36: 519±25.
3 Vickers AJ. Can acupuncture have
specific effects on health? A systematic
review of acupuncture antiemesis trials.
Journal of the Royal Society of Medicine
1996; 89: 303±11.
4 Chiang CY, Chang CT, Chu HL, Yang
LE. Peripheral afferent pathways for
acupuncture analgesia. Scientia Sinka
1973; 16: 210±17.
Electroencephalographic
arousal response during
tracheal intubation and
laryngeal mask airway insertion
after induction of anaesthesia
with propofol
Having studied the effect of tracheal
intubation and other noxious stimuli on
evoked potentials of the EEG [1, 2] I
have no doubt that the arousal in
response to airway manipulation
detected by Inada and colleagues
(Anaesthesia 1999; 54: 1150±4) does
indeed occur. In order to detect a
difference in the degree of arousal
between two different stimuli however,
steady-state plasma concentrations of
anaesthetic must be present before the
stimulus is applied. By ensuring this,
one can exclude variations in anaesthetic plasma concentrations as a cause
for arousal. This is particularly true
when using intravenous anaesthetics
such as propofol, when it is extremely
difficult to predict plasma concentrations. It is a pity that although the
patients in this study had arterial lines,
plasma propofol concentrations were
not measured to allow an accurate
comparison between patients to be
made.
In addition, although it seems from
the EEG data that significant arousal
occurred following intubation, the lack
of a control group, i.e. a group of
unintubated patients, does not exclude
the fact that arousal may have occurred
simply because propofol levels were too
low to keep the patients asleep. In fact,
relative delta power began to fall and
alpha and beta power began to rise 1±
2 min before airway manipulation. This
implies that the patients were getting
lighter before they were intubated.
The investigators cannot conclude
from this study that the degree of EEG
arousal caused by intubation and laryngeal mask insertion is the same. In
order to do this, it is important to
include a proper control group in
whom the stimulus is not applied and
ensure that steady-state conditions exist
prior to applying the stimulus.
M. Brunner
Northwick Park,
Harrow HA1 3UJ, UK
References
1 Brunner MD, Crabb IJ, Millett SV,
Thornton C, Newton DEF. Alfentanil
obtunds the increase in Pa amplitude
associated with intubation in a dose
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................................................................................................................................................................................................................................................
dependent fashion. Anesthesiology 1995;
83: 3A:A301.
2 Brunner MD, Nathwani D, Rich P,
Thornton C, Dore C, Newton DEF.
The effect of suxamethonium on the
auditory evoked response in man.
British Journal of Anaesthesia 1996; 76:
34±7.
A reply
As Dr Brunner points out, any possible
differences in the depth of anaesthesia
between patients at insertion of the
airway can be a confounding factor, and
a decrease in propofol concentration
might have caused the EEG arousal
pattern detected in our study. However,
since we randomised patients into two
groups to receive either a tracheal tube
or a laryngeal mask airway (LMA),
theoretically there should be no difference between the groups in the depth of
anaesthesia at insertion of the airway.
To study the degree of arousal during
insertion of an airway, it is necessary to
ensure the standardised steady-state
plasma concentrations of anaesthetic at
insertion of the airway; but this was not
our aim. The main aim of our study was
to study `whether noxious stimulations
of different intensity cause different
degrees of EEG arousal response'. We
used different noxious stimuli as tracheal
intubation and insertion of an LMA,
since it is known that, compared with
LMA insertion, laryngoscopy and tracheal intubation produce a significantly
stronger noxious stimulus to haemodynamic changes. We found that there was
no significant difference in the EEG
changes between groups in the presence
of a significant difference between
groups in the intensity of haemodynamic stimulation.
T. Inada
K. Shingu
Kansai Medical University Hospital,
Osaka 570±8507, Japan
A leaking Biovalve intravenous
catheter
We wish to report an unusual incident
regarding the failure of a Vygon
q 2000 Blackwell Science Ltd
Biovalve 14-gauge intravenous cannula.
During a routine elective operating
theatre case, a Vygon Biovalve 14gauge cannula was inserted in the
dorsum of the left hand of the patient
prior to induction of anaesthesia and
secured with tape in the usual manner.
The anaesthetist then turned his attention to the drawing up of induction
agent, briefly returned his attention
back to the patient to notice a steady
flow of blood exiting from the injection
port of the cannula. Approximately
15 ml of blood was lost via the faulty
valve mechanism.
We feel that this represents a potentially life-threatening fault in this type of
cannula, especially when venous access
sites are obscured by surgical drapes, and
would like to draw your attention to its
possible occurrence.
J. C. J. Wright
J. J. Tarpey
Warwick Hospital,
Warwick CV34 5BW, UK
A reply
After receiving the leaking Biovalve
cannula from Warwick Hospital and
completing our examination of the
device, we are pleased to be able to
offer a reply to Drs Wright and Tarpey.
We have found that the silicone tube
that sits inside the hub of the cannula
acting as a one-way valve had been
distorted and was not fully covering the
port. Whilst we have not been provided
with a Lot number with which we can
definitively identify this device, we
believe that it is in fact a model that
was produced prior to being upgraded
to be manufactured using a state of the
art fully automated assembly machine.
This machine performs a number of inprocess tests including a measured flow
test and would identify and automatically remove any device that does not
meet the flow parameters; in this case a
high measurement would have been
recorded.
Over the years in which the Biovalve
has been manufactured, we only have
one other report on our database where
a blood leak through the injection port
was discovered in use. This occurred in
1997 and unfortunately the device was
discarded before we were able to
examine it and confirm the cause of
the problem. From this we believe that
this is an isolated incident.
We sell some 4 million Biovalves a
year in the UK alone and always hope
that there will be no problems. In
reality, we accept that occasionally we
will have a product with a problem,
such as occurred with this Biovalve, and
for this we offer our unreserved apologies and our assurances that we will
continue to work towards the ultimate
goal of zero product problems.
This incident has highlighted an area
where, as a manufacturer, we would ask
for the help of the readers of Anaesthesia
in reducing the potential numbers of
problems encountered through faulty
devices. We found out about this
incident a month, or possibly more,
after it occurred when we were offered
the opportunity to reply to the letter
sent to Anaesthesia. We immediately
checked with the Medical Devices
Agency and found it had not been
reported to them, so that our first
contact with the hospital was that
same day, when we were able to recover
the cannula for examination.
If anyone has a problem with a
device, reporting an incident to either
the manufacturer (we think we can
speak on behalf of the majority of
reputable manufacturers), or the MDA
should be done as quickly as possible.
This gives the best possible opportunity
to examine for batch-related problems
and, when this is found to be the case, a
speedy product recall. Any delays may
result in further incidents and, as Drs
Wright and Tarpey point out, with a
potentially life-threatening fault, such
an incident may have a very different
ending as happened this time.
The MDA, as well as many other
excellent services, have an Adverse
Incident Centre where either the user
or the manufacturer, who has a legal
obligation to do so, may report an
Adverse Incident. The MDA will then
follow through the report with both the
user and manufacturer in order to try to
stop any recurrence of that incident or
any similar incidents. The MDA
Adverse Incident Centre can be
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Correspondence
Anaesthesia, 2000, 55, pages 590±619
................................................................................................................................................................................................................................................
contacted on 0171 9728080 or by fax
on 0171 9728109.
G. Milward
Technical Support Services,
Vygon (UK),
Cirencester GL7 1PT, UK
Editorial comment
We remind readers that they have a
professional responsibility to report any
incident involving faulty equipment to
the manufacturer or the Medical Device
Agency at the earliest opportunity.
Leaking vaporiser
With reference to the editorial by
Cartwright and Freeman (Anaesthesia
1999; 54: 519±20), leakage of anaesthetic agent seems to be one of the
commonest problems associated with
vaporisers. Typically, an average hospital
has a large number of anaesthetic
machines and even larger variety of
vaporisers in use. Financial constraints
prevent achievement of uniformity of
the anaesthetic equipment at various
locations of the hospital. The process of
mounting and demounting of the
vaporisers on the backbar of the anaesthetic machine during an anaesthetic
procedure is potentially risky. Transporting the vaporiser from the anaesthetic room to the operating theatre
during the course of the transfer of the
anaesthetised patient is a further source
of complications. I wish to report a
problem that occurred as a result of
transfer of the vaporiser during one of
the anaesthetic procedures.
Routine check of the anaesthetic
machines in the anaesthetic room and
the operating theatre was performed at
the start of the list. Both these machines
had enflurane vaporisers `Enfluratec' (Tec
3) in place. The first half of the list went
uneventfully. A patient listed halfway
through the list had a history of epilepsy;
therefore, isoflurane was selected as the
agent of choice for the anaesthetic.
However, there was only one isoflurane
vaporiser available for the anaesthetic
room and the operating theatre. The
vaporiser (Ohmeda, Isotec 5) had been
tested and found to be compatible with
the backbar of the machine in the
606
Figure 3 The close up of the Isotec 5 vaporiser showing downwards displacement of the
locking lever of the key filler port (a) and the partially open draining valve tap (b).
anaesthetic room as well as that in the
operating theatre. The anaesthetic was
commenced in the anaesthetic room
using an intravenous induction and a
laryngeal mask was inserted. Anaesthesia
was maintained with a mixture of
oxygen, nitrous oxide and isoflurane.
The patient was transferred to the
operating room and simultaneously the
isoflurane vaporiser was dismounted
from the machine in the anaesthetic
room and remounted on the backbar of
the anaesthetic machine (Datex Flexima)
in the operating theatre by the theatre
assistant. On reconnection of the breathing circuit to the patient, inability to
achieve a satisfactory pressure in the
circuit was noticed despite high flow of
the gases. The patient's lungs were being
ventilated manually at this stage. A
systematic inspection of the assembly
revealed a steady drip of the contents
(isoflurane) from the Isotec 5 vaporiser.
On closer inspection, the locking lever
of the key filler port on the left side of
the vaporiser (a) was noted to be
displaced downwards; additionally, the
valve tap at the base of the vaporiser (b)
was found to be partially open, resulting
in the drip (Fig. 3). The situation was
rapidly rectified by repositioning the
levers in the correct place and the gastight seal was restored. The vaporiser was
topped up and there was no problem in
maintaining the depth of anaesthesia.
It appeared that the valve tap had
probably been accidentally knocked
open as the vaporiser was being
remounted on the backbar of the
anaesthetic machine in the operating
theatre. As seen in Fig. 4, there was a
very snug fit between the frame of the
anaesthetic machine and the base of the
Isotec 5 vaporiser. Additionally, the space
between the left-hand side of the Isotec 5
vaporiser bearing the lever for the key
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Figure 4 The double vaporiser assembly showing the tight fit between the two
vaporisers and the frame of the anaesthetic machine in relation to the base of the Tec 5.
filler and the filling port of the adjacent
Enfluratec vaporiser was very tight. This
left no room for fingers to support the
bulky Tec 5 vaporiser at its base or on the
left side. The only available space was
towards the lower outer right-hand
corner of the Tec 5. It is easy to see
how the draining valve tap near the base
could have been accidentally flicked
open during a rushed procedure.
Fortunately, due to timely intervention,
the drop in the end-tidal concentration
of the vapour was prevented. Figure 5
shows a much larger space available
between the two adjacent vaporisers
when the relative positions of the two
were reversed; however, the tight vertical
fit with the Tec 5 remained unchanged.
This case illustrates the fact that the
problems can occur despite adequate
checking of the equipment. The draining
valve tap of the Tec 5 vaporiser is rather
easily opened unlike others, where emptying of the vaporiser would involve a
series of deliberate manoeuvres. The valve
tap is not secured by any locking device.
Additionally, it might be difficult to spot a
partially open valve when viewed from
the front. The accidental opening of the
valve is thus a potential problem. These
vaporisers have been around for nearly
10 years. Personal communication with
the quality control manager at the DatexOhmeda UK revealed a couple of other
reports of accidental draining of the Tec 5
vaporiser. In the first one the valve was
entangled with the monitoring leads and
another occurred during a cleaning
process of the equipment. As it would
be a monumental task to alter the design
of the vaporiser, it is suggested that the
valve tap be secured with some tape
during use as well as for transfers. The
spillage of the anaesthetic agent not only
results in environmental pollution, it is
also likely to damage the surface of the
machine underneath.
In an ideal world, every anaesthetic
machine would have a dedicated
vaporiser for the relevant anaesthetic
agent, thus obviating the need for
transportation of vaporiser from one
location to another mid-anaesthetic.
Despite the best of efforts, it might
not be possible to equip all the machines
in such a way. One solution would be to
anaesthetise the patient in the operating
theatre. This would abolish the need for
duplication of the equipment in the
anaesthetic room and the operating
theatre. Furthermore, the hazards associated with the transfer of the equipment and the anaesthetised patient from
the anaesthetic room to the operating
theatre would be eliminated.
S. B. Vohra
City Hospital,
Birmingham B18 7QH, UK
A reply
Figure 5 The double vaporiser assembly with the positions reversed.
q 2000 Blackwell Science Ltd
Thank you for giving me the opportunity to reply to Dr Vohra's letter
607
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Anaesthesia, 2000, 55, pages 590±619
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regarding the difficulty experienced
when mounting Datex-Ohmeda Tec 3
and Tec 5 vaporisers on a Flexima 1
anaesthesia workstation.
We assembled an identical Flexima 1
workstation in our service centre using
the vaporiser configurations shown in
Dr Vohra's figures. The results obtained
were the same as those reported by Dr
Vohra. There was little room to place
lifting fingers under either vaporiser,
making the mounting operation very
difficult. The Tec5 was an interference
fit with the floor of the Seletatec
mounting block tray. Clearly, the temptation under these circumstances is to
grasp the vaporiser by the side faces at
the point where the Tec 5 filler is
located. This may result in an accidental
opening of the drain control lever when
the fingers are removed from the
narrow gap between the two vaporisers.
Picking up the vaporiser by the percentage control knob situated on the top of
the vaporiser is similarly not recommended, particularly in the case of the
Tec 3 where there is a direct link
between the control knob and the
rotary valve controlling the flow of
anaesthetic agent.
We asked Dameca, the manufactures
of the Flexima 1 anaesthetic workstation, which vaporisers had been
recommended by them for this machine
when it was originally placed on the
market? Dameca said that the original
machines were manufactured to take the
Datex-Ohmeda Tec 4 vaporisers, which
are similar to the Tec 5 but much
shorter. We fitted Tec 4 vaporisers to
the Flexima 1 and found no difficulty in
supporting the weight of the vaporiser
from below without trapping fingers
between the vaporiser bottom and the
mounting block tray. Tec 3 vaporisers
are not recommended for this machine
and in fact cannot be fitted unless the
lockout pins are removed from the
backbar, an operation that we do not
recommend.
Dameca also advised that later versions of the Flexima 1 were manufactured with the backbar set higher above
the mounting tray, permitting the
satisfactory fitting of Tec 5 vaporisers.
It may be possible to modify these
earlier machines to the later standard.
608
From our response you see that the
compatibility of vaporiser to workstation is not a simple matter. We
recommend that vaporisers of a type
whose compatibility has been validated
by the original manufacturer are used to
avoid similar problems. Should the user
wish to use alternative items they should
ask their equipment supplier to confirm
compatibility.
M. Kersley
Quality, Safety and Environment
Manager for Datex-Ohmeda,
Hatfield AL9 5EN, UK
A `groovy' fibrescope
modification
Delay in passage of a tracheal tube
during fibreoptic intubation risks
patient hypoxia. Insufflation of oxygen
via the suction or instrumentation port
of the fibrescope will help prevent this
and will also prevent misting of the
objective [1]. Since the lever activating
the suction valve has to be continuously
held down on most fibrescopes to
provide a continuous supply of gas,
this makes for an extremely awkward
grip on the instrument.
We have developed a simple modification of the Olympusw LF-TP (Olympus Optical Co. Ltd, Tokyo, Japan)
portable fibrescope suction valve, which
allows a continuous oxygen stream to be
started and stopped at will. The suction
valve of this type of instrument (MD493) is surrounded by a plastic cowl with
two vertical slots in the wall. These slots
allow the flat metal bar of the suction
lever to be depressed, thus actuating the
valve. The cowl also provides the
Figure 6 The modified plastic cowl.
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Correspondence
................................................................................................................................................................................................................................................
mounting point for the single-use biopsy
valve (MAJ-210). By filing a small
(3 mm) horizontal groove or slot at
right angles to the existing vertical slot
close to the base of the cowl, the
actuating bar can be slid into this whilst
depressed, thus freeing the grip for
holding the fibrescope (Fig. 6). When
oxygen is not required the lever can be
`clicked' out of the groove and returns
automatically to the `off ' position. The
best size of file for this purpose is a flat
needle file approximately 5 mm wide
and 1.5 mm thick. We have forwarded
the prototype cowl via Keymed UK to
development staff at Olympus for their
consideration of this as a permanent
modification for future instruments.
J. H. MacG. Palmer
D. R. Ball
Dumfries and Galloway Royal
Infirmary,
Dumfries DG1 4AP, UK
Reference
1 Benhumof JL. Management of the
difficult adult airway with special
emphasis on awake tracheal intubation.
Anesthesiology 1991; 75: 1087±110.
Reinforced laryngeal mask
airway severed by biting
I would like to respond to the report by
Quinlan of a severed reinforced laryngeal mask airway (Anaesthesia 2000; 55:
186). The manufacturers, IntaventOrthofix, have distanced themselves
from the name `reinforced laryngeal
mask'. The correct name of the device
is the Flexible Laryngeal Mask Airway
(FLMA). In the instructions for use it is
clearly stated that the flexometallic tube
is kink proof, but not bite proof and
cannot withstand strong compressive
forces [1]. Further, it is recommended
that a bite block be used in cases where
an FLMA is used. Although surprising
that a patient emerging from anaesthesia
could bite through the wire, reported
evidence serves as a reminder that the
instructions for use should be adhered
to, and use of the correct device name
q 2000 Blackwell Science Ltd
may avoid confusion as to its properties.
It is also currently recommended practice to use a size 5 in adult males.
C. Stonell
Royal Berkshire Hospital,
Reading RGI 5AN, UK
Reference
1 Brimacombe JR, Brain AIJ, Berry AM.
Laryngeal Mask Airway Instruction
Manual, 4th edn. 1999; 23.
Ambiguous drug labelling on
ampoules containing local
anaesthetic solution
We would like to bring to your readers'
attention a case of confusing drug
labelling. At our request to the anaesthetic nurse to provide us with a 10-ml
ampoule of bupivacaine 0.5% with
epinephrine (adrenaline) 1 : 200 000 for
surgical wound infiltration, we were
provided with an ampoule with the
following label: bupivacaine with epinephrine 0.5%. As it was not clear to us
whether this constituted a 0.5% bupivacaine or 0.5% epinephrine solution we
proceeded to further checks of the
packaging of the ampoule which revealed
the same ambiguous drug label. Only the
box containing the batch of ampoules
from which our ampoule was drawn stated
unequivocally an epinephrine concentration of 10 mg.ml21 and a bupivacaine
concentration of 5 mg.ml21. Previous
ampoules as well as their packaging
provided clear unequivocal labelling of
concentrations of epinephrine and
bupivacaine (Fig. 7).
We would like to advocate a return to
the previous method of drug labelling to
avoid confusion.
S. Gupta
J. W. Zwaal
Kingston Hospital,
Kingston Upon Thames KT2 7QB,
UK
A reply
AstraZeneca would like to make the
Figure 7
following comments in response to the
letter by Drs Gupta and Zwaal concerning the change in labelling of
Marcainw and epinephrine.
We would firstly like to take the
opportunity to reassure our customers
that the formulation of the product has
not changed in any way. Every product
must have the full registered trade name
of the product (i.e. that listed on the
product licence), clearly marked on the
outer packaging and individual components. The registered names of the two
presentations are:
Marcain with epinephrine 0.5%; and
Marcain with epinephrine 0.25%.
This appears on the outer packaging
and also the individual ampoules. In
addition, the amount of epinephrine is
quoted on the outer packaging and is
expressed as epinephrine tartrate
10 mg.ml21, which is equivalent to
5.5 mg.ml21 base.
In response to recent customer feedback concerning the change in labelling
of the product, we are currently planning to amend the labelling on both
outer cartons and individual ampoules,
to clearly indicate the strength of both
609
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Anaesthesia, 2000, 55, pages 590±619
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the bupivacaine and the epinephrine.
We hope that these amendments will
make the labelling more convenient to
our customers.
We would like to reiterate that no
change in the formulation of the
product has occurred, and that the
product can continue to be used in
accordance with current medical
practice.
R. Rowsell
Medical and Regulatory Affairs
Director,
AstraZeneca,
Kings Langley WD4 8DH, UK
Paediatric intensive care
transfers
We write to express our concern about
the current trends in paediatric intensive
care. We work in a district general
hospital and recently managed an 18month-old with acute epiglottitis, a rare
event nowadays following HIB vaccination. We followed the standard teaching
using oxygen and halothane (we were
not brave enough to use sevoflurane), to
`breath the child down' in the operating
department. Following successful intubation, vascular access and full monitoring were established. We kept the child
ventilated, paralysed with atracurium
and anaesthetised in the theatre department, and waited for the paediatric
intensive care team from a local teaching centre to pick the child up. They
duly arrived and we handed over to the
team. They wanted more vascular access
and commenced various infusions for
transfer. After the handover we continued with other duties and thought
that everything would be fine in the
hands of the experts from the teaching
centre.
While R.G. was changing he was
quickly summoned to assist with the
child again who had coughed the tube
out. Neither the consultant paediatric
intensivist nor the registrar could reintubate the child. R.G. breathed the
child down again and re-intubated it,
this time showing the laryngoscopic
findings to the paediatricians who had
never seen the condition before. A 40mile ambulance journey followed and
610
the child made a full recovery. However,
this case has some worrying features,
which we would like to raise.
Firstly, is it safe to transfer a critically
ill child 40 miles with a team that
cannot re-intubate the patient if a
problem occurs? Would we send a
ventilated head injured patient in the
back of an ambulance with a surgical
house officer? Second, the rush to
transfer to a specialist unit may be
satisfactory in large urban areas but in
East Anglia there are large distances
between district general hospitals and
the specialist centres. Many patients
who are now routinely transferred
were well managed in our own units
until a couple of years ago.
We need a return to common sense.
District general hospitals, if they have
the expertise, should be encouraged to
perform the initial resuscitation of the
severely ill child and the following 24±
48 h of intensive care. This used to be
the case in our hospital and most
children so treated did very well. It
was the agreement to transfer to a PICU
if, after this initial period, more specialist help was needed. This meant that
the patient was transferred electively
with the patient in as stable a condition
as possible. The current situation of the
knee jerk referral and transfer to a
specialist centre has two very bad outcomes. One is to deskill the very
hospitals that are responsible for saving
the child's life, and will continue to have
to do so. Two is that transfer occurs at
the very worst time for the patient,
when physiology is most compromised.
Talking to our paediatric colleagues
has led us to believe they share very
similar views. The immediate transfer of
all paediatric patients needing intensive
care may not be the best solution and a
rethink is needed.
R. Griffiths
H. Smith
Peterborough District Hospital,
Peterborough PE3 6DA, UK
Pre-operative fasting in the
older child
In the past 2 years, three surveys have
been published looking at pre-operative
fasting practices in children [1±3]. In
each of these surveys, the majority of
paediatric anaesthetists in three countries stated that they would restrict solid
food intake in a child older than 3 years
for at least 6 h pre-operatively. Two
recent cases at our hospital, which came
to light through our critical incident
reporting scheme, suggest a longer
period of fasting for solid foods may
be necessary.
Case 1. A 6-year-old boy presented
for circumcision under general anaesthesia on an outpatient basis. He had
been fasted for solid food for 8 h.
Anaesthesia was induced with propofol
and fentanyl, and maintained using a
laryngeal mask airway (LMA) with
isoflurane and nitrous oxide in oxygen.
A penile block was performed for
postoperative analgesia. On removing
the LMA at the end of the operation,
the patient regurgitated a large amount
of semidigested solid food. No morbidity ensued. On further questioning of
the child and parent postoperatively (in
a nonconfrontational manner), it
became apparent that the child had
had a large meal approximately 9 h preoperatively, but no solids after that.
Case 2. A 10-year-old girl presented
for unilateral inguinal herniotomy
under general anaesthesia on an outpatient basis. She had been fasted for
solid foods for 8 h. Anaesthesia was
induced with propofol and fentanyl, and
maintained using an LMA with isoflurane and nitrous oxide in oxygen. An
ilio-inguinal nerve block was performed
for postoperative analgesia. On skin
closure by the surgeon, the patient
suddenly regurgitated with vomit
coming out through the proximal end
of the LMA; the vomit contained
semidigested food. The patient was
intubated, surgery completed and no
morbidity ensued. On further nonconfrontational questioning of the child and
parent postoperatively, ingestion of solid
food within 8 h of surgery was denied.
Most solid food exits the stomach
within 4 h. Gastric emptying can be
greatly prolonged in children by anxiety,
stress or pain. It is reasonable to assume
that most children will feel anxious the
night before surgery and gastric emptying may be prolonged; the two cases we
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................................................................................................................................................................................................................................................
report provide some evidence of this.
The normal practice in our hospital is to
fast children older than 12 months for
6 h for solid foods and 2 h for clear
fluids pre-operatively. We are revising
this guideline on a trial basis to no solid
food intake for 12 h and no clear fluids
for 2 h pre-operatively.
Two published series on aspiration of
gastric contents in children suggest that
aspiration pneumonitis is an uncommon
problem, and that it causes much less
morbidity and mortality than commonly supposed [4, 5]. Nevertheless, it
would seem prudent to avoid aspiration
if possible. If after audit, our new fasting
guidelines are shown to decrease the
incidence of peri-operative vomiting,
we shall implement them on a permanent basis.
G. M. Sanders
Medway Hospital,
Gillingham ME7 5NY, UK
References
1 Ferrari LR, Rooney FM, Rockoff MA.
Preoperative fasting practices in
pediatrics. Anesthesiology 1999; 90:
978±80.
2 Emerson BM, Wrigley SR, Newton
M. Pre-operative fasting for paediatric
anaesthesia. A survey of current
practice. Anaesthesia 1998; 53: 326±30.
3 Haas U, Motsch J, Schreckenberger R,
Bardenheuer HJ, Martin E.
Premedication and preoperative fasting
in pediatric anaesthesia. Results of a
survey. Anaesthesist 1998; 47: 838±43.
4 Borland LM, Sereika SM, Woelfel SK
et al. Pulmonary aspiration in pediatric
patients during general anesthesia:
incidence and outcome. Journal of
Clinical Anesthesia 1998; 10: 95±102.
5 Warner MA, Warner ME, Warner DO,
Warner LO, Warner EJ. Perioperative
pulmonary aspiration in infants and
children. Anesthesiology 1999; 90: 66±
71.
The stress response in children
during laparoscopic abdominal
surgery
I was saddened to note that the first
q 2000 Blackwell Science Ltd
scientific paper in Anaesthesia in the new
millennium made little reference to
anaesthesia itself. Bozkurt et al. (Anaesthesia 2000; 55: 5±9) studied the endocrine and metabolic responses of 29
children undergoing operations for
abdominal pain. The paper discusses
various factors affecting the responses to
surgery including the size of the skin
incision, the amount of tissue damage
and the effects of the pneumo-peritoneum. However, the effects of anaesthesia are ignored.
It has been known for some time that
in the early peri-operative period
regional anaesthesia attenuates (or may
even abolish) the neuroendocrine
response to surgery [1±2] compared
with patients undergoing the same
operation but with a general anaesthetic. The metabolic profiles tend to
become similar by 24 h, perhaps
because of the effects of fasting and/or
tissue damage.
Barker et al. [3] showed that even in
operations where there was virtually no
tissue damage, there might be a doubling of the plasma cortisol concentration from a baseline before anaesthesia
started until 60 min after the end of
surgery.
The same group [4] subsequently
showed that the emergence from anaesthesia itself has a significant effect on the
plasma cortisol level that had previously
been masked by the stress response to
surgery. They compared three groups
undergoing cataract surgery. Two of the
groups had general anaesthesia alone
(GA) and retrobulbar block alone (RB).
The third group (GA 1 RB) had a
general anaesthetic followed by a retrobulbar block before surgery. There was
no significant difference in cortisol
levels between group GA 1 RB and
group RB until the end of surgery.
However, the serum cortisol level in
group GA 1 RB then doubled in the
first 30 min post surgery until there was
no significant difference compared with
group GA.
Bozkurt et al. measured the cortisol
levels from 5 min after induction until
extubation. All the metabolic indicators
that they measured were within the
normal ranges and there were no
significant differences between the final
values in the two groups of patients.
Induction and emergence are possibly
the most important parts of anaesthesia
and the neuroendocrine markers of the
response to `operations' seem to underline this point. Perhaps if the anaesthetists hadn't been outnumbered as
authors then this point would have
been addressed.
It is clear that certain types of
laparoscopic surgery offer significant
advantages to patients in terms of
recovery and complication rate when
compared with the `open' alternatives.
However, what still remains far from
clear is the meaning of the changes in
various metabolic markers as a consequence of surgery and anaesthesia.
D. Dalgleish
St Helier,
Jersey JE2 3XG, UK
References
1 Kehlet H, Brandt MR, Hansen AP,
Alberti KG. Effects of epidural analgesia
on metabolic profiles during and after
surgery. British Journal of Surgery 1979;
66: 543±6.
2 Namba Y, Smith JB, Fox GS, Chalis JR.
Plasma cortisol concentrations during
Caesarean section. British Journal of
Anaesthesia 1980; 52: 1027±32.
3 Barker JP, Robinson PN, Vafidis GC,
Hart GR, Sapsed-Byrne S, Hall GM.
Local anaesthesia prevents the cortisol
and glycaemic response to cataract
surgery. British Journal of Anaesthesia
1990; 64: 442±5.
4 Barker JP, Robinson PN, Burrin JM,
Hall GM. Retrobulbar block fails to
prevent an increase in serum cortisol
concentration on emergence from
anaesthesia after cataract surgery. British
Journal of Anaesthesia 1994; 72: 119±21.
A reply
We are grateful for the opportunity to
respond to Dr Dalgleish's letter. We are
also aware of the effects of anaesthesia
on the stress response. The purpose of
the study was to evaluate the effects of
surgical technique on stress hormones
intra-operatively. In order to achieve
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our goal we used a standardised anaesthesia technique in both study groups
while several conflicting reports about
the effects of general anaesthetics on
neuroendocrine response exists [1, 2].
In our anaesthetic technique the dose of
morphine used during induction is not
enough to suppress the stress response
and no regional anaesthetic technique
was applied [3]. Induction, intubation
and emergence affect the stress response
during general anaesthesia. In this study
blood samples were withdrawn 5 min
after induction and intubation (the
word intubation was not stressed in
the manuscript and might have caused
misunderstanding) when atracurium,
morphine and isoflurane were on
board for at least 5 min in both
groups. The effects of intubation and
induction were included on TO measurements. The samples were withdrawn at the end of the surgery prior
to extubation Tend, excluding the effects
of extubation. When one parameter is
kept constant the outcome depends
mostly on other factors, in this case
the surgical technique. Cortisol was the
main parameter in the referred literature
in Dr Dalgleish's letter [4] that may
increase intra-operatively regardless of
anaesthetic technique [5]. In this study
cortisol was not the only parameter
followed; epinephrine, insulin, glucose,
prolactin and interleukin 6 (where there
is a sole parameter for tissue trauma)
levels were also measured. The overall
evaluation of these parameters proves
the similarity between groups. Nevertheless, we would like to thank Dr
Dalgleish for pointing out the effects of
general anaesthesia on the stress
response. The effects of laparoscopy on
the stress response are published both in
anaesthesia and surgery journals and
include contributions by anaesthetists
and surgeons [6±9].
We are currently running the same
study, both intra-operatively and postoperatively, on patients after parental
approval. Acetaminophen 20 mg.kg21
PR every 6 h is used for postoperative
pain relief. Blood samples are being
taken after 12 h and 24 h postoperatively. The results from eight patients
(n 4 open appendicectomy, n 4
laparoscopic appendicectomy) reveal a
612
similar trend intra- and postoperatively
in both groups. The glucose, prolactin
and cortisol levels are depressed after
12 h and return to control values at
24 h. As anaesthetists, we have to keep
in mind that laparoscopic interventions
in children have similar neuroendocrine
response and have to consider the use of
techniques that can also abolish the
stress response during laparoscopic
surgery.
P. Bozkurt
Istanbul University Cerrahpasa
Medical Faculty,
34303 Istanbul, Turkey
1
2
3
4
5
6
7
References
Carli F, Ronzoni G, Webster J, Khan K,
Elia M. The independent metabolic
effects of halothane and isoflurane
anesthesia. Acta Anaesthesiologica
Scandinavica 1993; 37: 672±8.
Furuya K, Shimizu R, Hirabayashi Y,
Ishii R, Fukuda H. Stress hormone
responses to major intra-abdominal
surgery during and immediately after
sevoflurane- nitrous oxide anaesthesia
in elderly patients. Canadian Journal of
Anaesthesia 1993; 140: 435±9.
Hall GM, Ali W. The stress response
and its modification by regional
anaesthesia. Regional Anaesthesia 1998;
53 (S2): 10±2.
Barker JP, Robinson PN, Burrin JM,
Hall GM. Retrobulbar block fails to
prevent an increase in serum cortisol
concentration on emergence from
anaesthesia after cataract surgery. British
Journal of Anaesthesia 1994; 72: 119±21.
Aono H, Takeda A, Tarver SD, Goto
H-. Stress responses in three different
anesthetic techniques for carbon
dioxide laparoscopic cholecystectomy.
Journal of Clinical Anesthesia 1998; 10:
546±50.
Myre K, Rostrup M, Buanes T,
Stockland O. Plasma catecholamine and
hemodynamic changes during
pneumoperitoneum. Acta
Anaesthesiologica Scandinavica 1998; 42:
343±7.
Kristiansson M, Saraste L, Soop M,
Sundqvist KG, ThoÈrne A. Diminished
interleukin-6 and C-reactive protein
responses to laparoscopic versus open
cholecystectomy. Acta Anaesthesiologica
Scandinavica 1999; 43: 146±52.
8 Engin A, Bozkurt B, Ersoy E, Oguz M,
GoÈkcËora N. Stress hyperglycemia in
minimally invasive surgery. Surgical
Laparoscopy and Endoscopy 1998; 18:
435±7.
9 Goodale R, Beebe D, McNevin MP,
Boyle M, Letourneau JG, Abrams J,
Cerra B. Hemodynamic, respiratory,
and metabolic effects of laparoscopic
cholecystectomy. American Journal of
Surgery 1993; 166: 533±7.
A simple method of sub-Tenon
anaesthesia delivery
In ocular regional anaesthesia today, the
sub-Tenon/parabulbar technique is
gaining popularity [1]. The fear of
sharp needle complications during retrobulbar or peribulbar injections including perforation of the globe,
subarachnoid injection, retrobulbar haemorrhage [2] and respiratory complications [3] are leading many anaesthetists
towards this blunt cannulae local anaesthetic delivery technique. Although
most published studies refer to Stevens'
method [4], other methods are in use,
which include Greenbaum [5] and
Fukasaku [6]. These techniques involve
gaining access to sub-Tenon's space by
incising the conjunctiva and tenon's
capsule 3±5 mm away from the limbus
and subsequent lifting of the capsule
which allows the introduction of a blunt
cannula and subsequent injection of
local anaesthetic agent; but where they
differ is in the quadrant of access and
the nature of the cannula.
We use a commercially available subTenon curved metal cannula but during
a brief period the metal cannula was not
available in our unit. The design of this
cannula led us to think if local anaesthetic can be delivered by an alternative
method by introducing a readily available intravenous plastic cannula sheath
without the introducer. The technique
is essentially similar to Stevens' technique [4]. The incision is made 3±5 mm
away from the limbus in the inferonasal
compartment. A 20G uncut intravenous
cannula (Fig. 8) is mounted on a 5-ml
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Figure 8 Intravenous cannula with syringe in sub-Tenon's space.
syringe filled with the local anaesthetic
of choice and is introduced through the
incised area and the desired amount of
local anaesthetic is injected. We have
successfully used this method of local
anaesthetic delivery through subTenon's space with good results and
without problems. The intravenous
plastic cannulae are readily available in
all hospitals. These are cheaper, £0.40±
0.60 in comparison with commercially
available metal cannulae, £2±4. Smaller
gauges, e.g. 20±22, are suitable in
length but are prone to kinking in the
space. On the other hand, higher
gauges, e.g. 16±18, are tougher but
are longer in length.
We suggest that this method of subTenon anaesthesia delivery is a simple,
readily available, cheap, safe and effective alternative to commercial cannulae
if not available.
C. M. Kumar
S. Williamson
R. Chabria
South Cleveland Hospital,
Middlesborough TS4 3BW, UK
References
1 McLure HA, Rubin AP. Local
anaesthesia for ophthalmic surgery.
Current Anaesthesia and Intensive Care
1999; 10: 40±7.
2 Rubin AP. Complications of local
anaesthesia for ophthalmic surgery.
British Journal of Anaesthesia 1995; 75:
93±6.
3 Kumar CM, Lawler PG. Pulmonary
oedema following peribulbar block.
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British Journal of Anaesthesia 1999; 82:
777±9.
4 Stevens JD. A new local anaesthesia
technique for cataract extraction by one
quadrant sub-Tenon's infiltration.
British Journal of Ophthalmology 1992;
76: 66±8.
5 Greenbaum S. Parabulbar anesthesia.
American Journal of Ophthalmology 1992;
114: 776.
6 Fukasaku H, Marron J. Pinpoint
anaesthesia: a new approach to local
ocular anaesthesia. Journal of Cataract
Refract Surgery 1994; 20: 468±71.
Epidural insertion under
general anaesthesia
Pursuing the discussion about `asleep'
vs. `awake' for the insertion of epidural
catheters (Anaesthesia 2000; 55: 288±90)
there are a few further arguments to
support the `awake' proponents.
1 Anaesthetists, like surgeons, act more
gently and circumspectly in using any
technique when the patient is awake.
This is always to the patient's benefit.
2 Keeping a patient awake requires that
the patient has a detailed explanation of
the epidural procedure beforehand, and
this helps to commit the anaesthetist to
a very clear decision about the risk/
benefit ratio.
3 The sitting position is available where
the anatomy may be difficult, e.g. the
obese patient.
4 There will be less back strain for the
anaesthetist and anaesthetist's assistants
when the patient is able to turn him/
herself at the end of the procedure.
No procedure is without risk of
complication. The incidence of complications is so low that we will wait a
long time for definitive evidence to
support the much awaited guideline
proposals from the European Society
of Regional Anaesthesia. Meanwhile
careful, wary technique remains the
most important factor. Many young
and restless patients will require general
anaesthesia prior to epidural injection,
but the majority can be well managed
awake, especially if one includes in this
definition the use of sedation by a small
dose of intravenous benzodiazepine!
M. J. Lindop
Addenbrooke's Hospital,
Cambridge, CB2 2QQ, UK
Effectiveness of blood
transfusion in Malawi
Having been very impressed by Dr
Fenton's study on the effectiveness of
blood transfusions for Caesarean section
in Malawi (Anaesthesia 1999; 54: 1055±
8), I contacted him to discuss the results
and enquire on specific concerns not
answered in the original article. Dr
Fenton was kind enough to share with
me additional data and we would like to
report further information on the
effectiveness of blood transfusions in
this context.
The results reported originally are
especially significant since they help
resolve a crucial issue on which very
little data are available, i.e. the effectiveness of allogeneic red cells to reduce
mortality in haemorrhagic shock. However, from the original report in
Anaesthesia, it was not possible to
determine the proportion of mothers
who survived/died while transfused or
not in the Central vs. District areas.
This may be important since transfusion
practice appears to be quite different
from one area of the country to
another.
Six thousand nine hundred and nine
(6909) patients are now included in the
database. Of these, 840 were deemed to
require a transfusion and 558 were
effectively transfused while 282 were
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not, owing to blood availability. Of the
transfused mothers, 33 died (5.9%) and,
of those who could not be transfused,
22 died (7.8%; p 0.369 by Chisquared). Thus, overall, transfusion of
red cells does not appear to decrease
mortality, as suggested in the original
publication. However, the situation is
very different in diverse parts of the
country. Blood is more readily available
in the District but much less readily
available in the Central Hospital. In the
District, 591 of the 4422 mothers
(13.4%) were deemed to require blood
and 432 (73%) were transfused. Of the
transfused mothers, 25 died (5.8%) and,
of those who could not be transfused,
18 died (11.3%), a statistically significant
difference (p 0.034 by Chi-squared).
Hence, in the District, blood transfusion
appeared to save lives, as we have been
taught to expect.
In the Central Hospital, 249 of the
2487 mothers (10%) were deemed to
require blood and 126 (51%) were
transfused. Of the transfused mothers,
eight died (6.3%) and, of those who
could not be transfused, only four died
(3.2%; p 0.399 by Chi-squared).
Mortality in mothers deemed to require
red blood cells, but not transfused, was
lower in the Central Hospital compared
with the District (3.2% vs. 11.3%,
respectively; p 0.022). Thus, in the
Central Hospital, not only does blood
transfusion not save lives, but it appears
to worsen outcome.
How can we explain this apparent
paradox? As stated originally, fluid
therapy is also very different in diverse
parts of the country. Volume replacement with nonblood fluids is aggressive
in the Central Hospital while the slow
transfusion of blood is often the only
volume administered in the District.
The additional data presented here
suggest that, globally, volume replacement is more important than red cell
transfusion in mothers with anaemia or
shock after Caesarean section. In
mothers appropriately volume resuscitated, transfusions appear to be deleterious, a situation similar to that observed
in industrialised countries where the
benefits of transfusions are not as
apparent as once thought [1].
These results are not those of a
614
randomised clinical trial, but we must
attempt to learn the most from the
difficult African medical situation. Dr
Fenton's observations are important for
all of us, but particularly in Africa where
blood may not always be readily available for fluid resuscitation and where, in
parts of the continent, the safety of
blood products is problematic (the
incidence of endemic HIV may be as
high as 20% [2±5]). In this context, we
encourage aggressive nonblood fluid
therapy for initial volume resuscitation.
Erythrocyte transfusions should be considered later and only when specific
indications for their administration
exist.
J-F. Hardy
University of Montreal,
QueÂbec, Canada
P. M. Fenton
College of Medicine, Malawi
References
1 Hebert PC, Wells G, Blajchman MA,
et al. A multicenter, randomized,
controlled clinical trial of transfusion
requirements in critical care.
Transfusion Requirements in Critical
Care Investigators, Canadian Critical
Care Trials Group. New England
Journal of Medicine 1999; 340: 409±
17.
2 Lackritz EM, Campbell CC, Ruebush
T, et al. Effect of blood transfusion on
survival among children in a Kenyan
hospital. Lancet 1992; 340: 524±8.
3 Lackritz EM, Ruebush T Kd, Zucker
JR, Adungosi JE, Were JB, Campbell
CC. Blood transfusion practices and
blood-banking services in a Kenyan
hospital. Aids 1993; 7: 995±9.
4 Zucker JR, Lackritz EM, Ruebush TK,
et al. Anaemia, blood transfusion
practices, HIV and mortality among
women of reproductive age in western
Kenya. Transaction of the Royal Society of
Tropical Medicine and Hygiene 1994; 88:
173±6.
5 Obonyo CO, Steyerberg EW, Oloo AJ,
Habbema JD. Blood transfusions for
severe malaria-related anemia in Africa:
a decision analysis. American Journal of
Tropical Medicine and Hygiene 1998; 59:
808±12.
Blood transfusion for Caesarean
section
We read with interest the article by
Fenton (Anaesthesia 1999; 54: 1055±8)
looking at blood transfusion for Caesarean section in Malawi. We recently
conducted a retrospective audit (a little
nearer home) looking at blood transfusion in women who had undergone
Caesarean section in our hospital during
a 12-month period (September 1998 to
August 1999).
Of the 557 Caesarean sections performed in this period, only 36 patients
had received a blood transfusion (6.5%).
Only 9% of the 1123 cross-matched
units were used. Nine patients were
transfused intra-operatively whilst 12
patients received blood between 4 h
and 4 days postoperatively. The mean
(SD) haemoglobin level of those
patients transfused more than 8 h after
surgery was 7.2 (1.6) g.dl21.
As a result of the audit, we are
currently negotiating changing a long
tradition of practice in our hospital.
Until now, it has been customary to
provide two units of cross-matched
blood in theatre at the time of surgery.
The evidence suggests that this is both
unnecessary and extremely wasteful of
time and money. The current opinion is
that an excessive number of units are
being cross-matched if the cross-match
to transfusion ratio is more than 2 : 1.
The ratio for Caesarean sections in our
hospital was 11 : 1! In addition, for
operations in which less than 10% of
patients require blood, a `group and
screen' policy is appropriate [1].
As Fenton rightly states, mothers (and
patients in general) die more commonly
from uncorrected hypovolaemia than
from actual anaemia. Young patients can
tolerate chronic and even acute anaemia
well, providing the circulating volume is
maintained, and should not be exposed
to blood transfusion without careful
thought. Peri-operative blood transfusion
has also been associated with increased
postoperative bacterial infection.
There is a lack of evidence to support
the use of `top-up' transfusions, particularly in healthy, well-nourished individuals. Although the risks from blood
transfusion are small, the majority of
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well-informed individuals must surely
prefer a short course of oral iron
supplements. This is a perfectly adequate and safe alternative.
Although probably behind the times
in that most hospitals have already
stopped
routinely
cross-matching
blood for all Caesarean sections, this
audit has highlighted the considerable
waste that is occurring in the blood
transfusion industry. The hospital transfusion committee has now decided to
audit all departments in the Trust,
starting with orthopaedic surgery, to
review the current use and abuse of the
blood transfusion service. This is long
overdue but may lead to the establishment of local policies for the crossmatch and transfusion of blood.
J. M. Cupitt
L. P. Raghavendra
Blackpool Victoria Hospital,
Blackpool FY3 8NR, UK
Reference
1 Contreras M, ed. ABC of Transfusion,
3rd edn. BMJ Books, 1998.
Identification of epidural space
using air with normal saline
Identification of the epidural space has
been achieved by a number of techniques, of which loss of resistance to air or
saline is the most commonly used.
Some anaesthetists prefer air while
others advocate using normal saline [1].
Whereas no serious adverse effects
have been associated with the use of
saline, there are a number of case reports
describing complications associated
with the use of air for identification of
the epidural space [2]. The list of
complications includes venous air
embolism, pneumocephalus and patchy
distribution of epidural block [2].
Despite this, a large number of
anaesthetists including ourselves have
been continuing to use air for identifying the epidural space. A recent survey
showed that more than 30% of obstetric
anaesthetists in Britain preferred air to
normal saline [3]. The superior quality
of the `feel' that one gets throughout the
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insertion of the Tuohy needle is the
reason why we prefer using air.
Recently, we devised a new approach
using both air and normal saline
together. We use a combination of
three-way taps connected together
between the Tuohy needle and the loss
of resistance syringe (Fig. 9). The side
ports of these three-way taps are connected using a short length of extension
tubing forming a vertical loop. The
three-way taps are then turned so that
they communicate with each other
through the extension tubing connected
to their side ports.
Normal saline is drawn up through
the Tuohy needle connected to this
assembly. Thus, the dead space of the
needle and the descending limb of the
loop formed by the extension tubing
contain normal saline. The syringe and
the ascending limb, on the other hand,
contain only air. The three-way taps are
locked, the tip of the Tuohy needle
inserted into the lumbar intervertebral
space selected and at a depth of 2 cm
the three-way taps are unlocked. The
needle is advanced feeling the resistance
to the column of air in the syringe and
the ascending limb of the loop. On
entering the epidural space, however, it
is the normal saline from the descending
limb of the loop that is injected first and
not the air. Using this technique, we
experience the same quality of resistance that is usually felt using air.
An extension tubing with two male
ends can be used to connect the threeway taps. We constructed our own as
shown in the figure. The dead space of
the descending limb should be 2±4 ml
as this is the volume that tends to get
injected at loss of resistance. The whole
assembly must be tested for leaks before
beginning the procedure.
S. S. Kale
S. A. Oosthuysen
James Paget Hospital,
Great Yarmouth N31 6LA, UK.
References
1 Scott DB. Identification of epidural
space: loss of resistance to air or saline?
Regional Anaesthesia 1997; 22: 1±2.
2 Saberski LR, Kondamuri S, Osinubi
OY. Identification of the epidural space:
is loss of resistance a safe technique? A
review of the complications related to
the use of air. Regional Anaesthesia 1997;
22: 3±15.
3 Howell TK, Prosser DP, Harmer M. A
change in resistance? A survey of
Figure 9 Arrangement of three-way taps and tubing attached to Tuohy needle and loss of
resistance syringe. Note that for the purpose of illustration an opaque liquid has been
used in place of saline.
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epidural practice amongst obstetric
anaesthetists. Anaesthesia 1998; 53:
238±43.
A method of administering
topical anaesthesia for flexible
airway endoscopy
We have found that a modified epidural
catheter inserted through the suction
port of the fibreoptic endoscope is an
effective method of accurately introducing local anaesthetic drugs to provide
topical anaesthesia for flexible airway
endoscopy. The distal end of a 16-gauge
epidural catheter is cut to remove the
side holes and is then threaded through
the suction port of an endoscope (in
our practice we use an Olympus LF-2).
It is advanced until the cut end of the
epidural catheter is flush with the distal
end of the endoscope. The proximal
end of the catheter is then attached to
its connector in the usual manner and
this is in turn attached to two threeway taps arranged in series. A 1-ml
syringe containing local anaesthetic is
fitted to the side port of the distal
three-way tap via a nonreturn valve.
The side port of the proximal threeway tap is left open to air and a 2-ml
syringe is attached to the other port via
a nonreturn valve. The plunger of the
2-ml syringe is removed and replaced
with a length of oxygen tubing connected to an oxygen supply at a flow of
1 l.min21 (Fig. 10).
Local anaesthetic solution is delivered
to the airway via the endoscope with
the help of an assistant who occludes the
open port of the proximal three-way tap
whilst simultaneously injecting 0.1±0.2ml aliquots of local anaesthetic via the
port of the other three-way tap
(Fig. 11). A 1-ml syringe is needed to
overcome the high pressure generated
by the gas flow. Injection produces a
fine jet of local anaesthetic, which can
be precisely targeted at areas of mucosa
at up to 5 cm distance from the tip of
the endoscope. The direction of spray of
local anaesthetic is controlled by movement of the tip of the fibreoptic endoscope. This allows the airway ahead of the
616
Figure 10
advancing endoscope to be accurately
anaesthetised under direct vision.
This technique is more time consuming than the usual spray-as-you-go
method but the fine spray produces less
coughing and gagging. We find this
device most useful for producing airway
anaesthesia if coughing has to be
minimised or if sedation is contraindicated, thus placing strenuous
demands on the local anaesthetic
technique.
D. O'Hare
R. Harwood
N. Woodall
G. Barker
Norfolk and Norwich Hospital,
Norwich NR1 3SR, UK
Figure 11
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Even simpler remifentanil
infusions
A simple way to calculate remifentanil
dosage (by dividing 3333 by body
weight (BW) in kg to give the volume
of dilutant for 2 mg) has been described
by Cort and Parsloe (Anaesthesia 2000;
55: 90). An even simpler method using
a standard dilution is given here.
2 mg remifentanil is dissolved in
40 ml dilutant, giving a concentration
of 50 mg.ml21.
0.5 BW in kg infusion rate in
ml.h21 25 mg.kg21.h2l 25/60 mg.
kg21.min2l 0.416 mg.kg21.min21.
Thus half the patient's BW given as
ml.h21 means the patient is receiving
0.4 mg.kg21.min2l, e.g. 60 kg patient
30 ml.h21 0.4 mg.kg21.min21. This
works for any weight.
From this it is easy to calculate
smaller or larger doses by further
halving, quartering or doubling the
infusion rate. Arithmetical errors are
less likely as dilution volumes do not
have to worked out with a calculator.
(My mental arithmetic is not always up
to dividing 3333 by BW, and it is easy to
get the decimal point wrong.) Mistakes
are also less likely with a standard
dilution. The concentration is the
same as fentanyl (50 mg.ml21), so is
already familiar to the anaesthetist, and
the bolus dose is readily worked out.
This may be more appropriate for
surgery with faster turnover than cardiac surgery. The patient's weight may
not always be known before arrival in
theatre, and using a standard dilution
the drug can be prepared in advance.
Accuracy to fractions of ml is less
essential for a drug with a very short
half-life such as remifentanil. It is easy to
titrate to clinical need and physiological
parameters, and the dose range of
remifentanil is very wide in any case
(0.05±2 mg.kg21.min2l). This method
goes some way to making remifentanil
more user friendly.
J. Millar
John Radcliffe Hospital,
Oxford OX3 9DU, UK
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Lessons from history
The early use of volatile anaesthetic
agents in the treatment of acute asthma
is effective but its use is not without
potential pitfalls [1].
A 40-year-old man presented to the
Accident & Emergency Department
with severe asthma. He had not
attended hospital or his general practitioner for 8 years and his case notes
were not immediately available. His
asthma was so severe that he was
unable to speak and his wife provided
the history to the casualty staff. This
included the fact that treatment of a
previous attack with aminophylline had
caused cardiac arrhythmias. He was
treated therefore with nebulised salbutamol and sodium cromoglycate, intravenous salbutamol and corticosteroids
and was admitted to the Intensive Care
Unit. The administration of a subanaesthetic dose of sevoflurane was considered. However, he began to respond to
the initial treatment and it became
possible to take a history and further
examine him. When questioned about
operations, he reported that he had
biopsy-proven malignant hyperpyrexia.
It was fortunate for both the patient and
his attendants that a volatile anaesthetic
agent or succinylcholine had not been
administered. His wife had not thought
to mention it, as his admission seemed
unrelated to the potential administration
of an anaesthetic.
This case teaches two important
lessons. The first is that a complete
history is essential, whether seeing a
patient pre-operatively or in the intensive care setting. The chance of an adult
presenting for an anaesthetic procedure
with malignant hyperpyrexia is approximately 1 : 40 000 [2] and with the
incidence of asthma in the adult population being 8.5% [3], the combined risk
of a patient suffering from both is in
excess of 1 : 470 000. While clearly
rare, the potential consequences should
make an enquiry about malignant
hyperpyrexia susceptibility an essential
component of a medical history if
exposure to trigger agents is likely.
The Royal College of Anaesthetists [4]
and the Association of Anaesthetists of
Great Britain and Ireland [5] publish
guidelines for pre-operative assessment.
Neither recommends direct enquiry
regarding malignant hyperpyrexia susceptibility. The second lesson involves
the value of the `Medic-Alert' bracelet.
They are inexpensive and available from
most pharmacies. This patient was not
wearing one and it could potentially
have cost him his life.
S. J. Wimbush
G. A. Morgan
Royal Cornwall Hospital,
Truro TR1 3LJ, UK
References
1 Padkin AJ, Baigel G, Morgan GA.
Halothane treatment of severe asthma
to avoid mechanical ventilation.
Anaesthesia 1997; 52: 994±7.
2 Dunn D. Malignant hyperthermia.
AORN Journal 1997; 65: 728±31.
3 Anon. Oxford Textbook of Medicine, Vol.
2, Section 15, 75±6. Year?
4 Website. www.rcoa.ac.uk.
5 Website. www.aagbi.org.
Facial hair, sex and facemasks
Dr McLure and colleagues have elegantly demonstrated that facemask
`wiggling' increases downward dispersal
of bacteria, but being a clean-shaven
male had a protective effect in this
respect (Anaesthesia 2000; 55: 173±6). I
sincerely hope that this will not lead to
the exclusion of female or bearded
anaesthetists from delivery suites.
In our unit we require that both the
anaesthetist and their assistant wear
freshly donned facemasks during regional anaesthetic procedures (in addition
to caps and, in the case of the
anaesthetist, gown and gloves). If the
parturient adopts the sitting position for
the procedure, she is also requested to
cover her hair. Since these precautions
have been followed we have had no
infective complications despite the fact
that our anaesthetists are encouraged to
maintain continuous verbal communication with their patients (entailing
mask `wiggling'). The advice of these
authors in a previous paper, that the
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head should be turned away during
speech (Anaesthesia 1998; 53: 624±6),
would thus considerably slow down
procedures ± a potential hazard particularly in the labouring patient. I agree
with the authors that a good aseptic
technique is of prime importance and
would like to see more detailed descriptions of this in reports of infective
complications.
F. S. Plaat
Queen Charlottes & Chelsea
Hospital,
London W6 0XG, UK
British syringe label `standards'
are an accident waiting to
happen
We agree with Dr Radhakrishna that a
consistent colour standard is required
for user-applied syringe labels (Anaesthesia 1999; 54: 963±8). Colour is a
powerful psychological cue [1±3],
which can facilitate the identification
of drugs. Some have argued that the use
of colour reduces the likelihood that the
label will be read. It should be emphasised that colour used correctly is a
supplement to, rather than a substitute
for, this important task. If colour coding
is applied by class of drug, the label must
still be read in order to identify the
specific drug within the class. The use
of more than one type of cognitive cue
(colour and text) provides multiple
opportunities to trap potential errors
before they occur. Such an approach is
consistent with the safety principles of
complex-systems theory developed in
the nuclear and aviation industries ± an
approach which anaesthesia is increasingly adopting in an effort to avoid
anaesthetic error and iatrogenic harm
[4±7].
However, if colour is to be used, a
consistent colour standard for drugs is
very important. The situation described
by Radhakrishna in Britain, with contradictory label systems used in different
hospitals and even within the same
hospital, is clearly an accident waiting
to happen. Faults like these in organisations are called latent errors and we
know from an extensive literature in
other fields that their existence guarantees
618
that it will only be a matter of time until
errors are made because of them [2±8].
In fact, it is very likely that such errors
have already happened. As Radhakrishna states, consistent colour-code
standards already exist in Australia,
New Zealand and the USA [9, 10],
and all of these use the same set of
colours for drug classes. An identical
colour standard also exists in Canada
[11]. However, it seems that the colours
used in Britain differ from the colour
standards used in these countries. This
creates a further problem for overseas
anaesthetists coming to work in Britain
and for British anaesthetists working
overseas.
Radhakrishna suggests that it may
take sometime before a consistent
colour standard can be adopted in
Britain and that in the interim British
anaesthetists should stop using colour as
a cue in syringe identification. This
seems counter-productive, however, as
the use of colour is currently widespread in Britain and can be a valuable
aid to safety. The simplest solution
would be for Britain to adopt the
colour standard used in the above
mentioned countries. The transition
involved in the adoption of any internationally consistent standard may carry
logistical difficulties and some risk.
With respect to user-applied syringe
labels, however, the safety benefits
would be considerable while the risk is
likely to be no more than continuing
with the status quo. We suggest that the
best approach would be for anaesthetists
to move to a consistent British standard
as soon as possible.
C. S. Webster
A. F. Merry
Green Lane Hospital,
Auckland, New Zealand
References
1 Merry AF, Webster CS. Labelling and
drug administration error. Anaesthesia
1996; 51: 987±8.
2 Reason J. Human Error. New York:
Cambridge University Press, 1990.
3 Perrow C. Normal Accidents: Living
with High-Risk Technologies. New York:
Basic Books, 1984.
4 Galletly DC, Mushet NN. Anaesthesia
system errors. Anaesthesia and Intensive
Care 1991; 19: 66±73.
5 Runciman WB, Webb RK, Lee R,
Holland R. System failure: an analysis
of 2000 incident reports. Anaesthesia
and Intensive Care 1993; 21: 684±95.
6 Gaba DM, Maxwell M, DeAnda A.
Anesthetic mishaps: breaking the
chain of accident evolution.
Anesthesiology 1987; 66: 670±6.
7 Webster CS, Merry AF, Larsson L,
McGrath M. A complex-systems
approach to safer drug administration
in anaesthesia. Journal of Clinical
Monitoring and Computing (abstract;
currently available from http://
www.scata.org.uk/articles/abstract/
autumn99.html).
8 Reason J. The contribution of latent
human failures to the breakdown of
complex systems. Philosophical
Transactions of the Royal Society of
London, Series B 1990; 327: 475±84.
9 Anon. User-applied labels for use on
syringes containing drugs used during
anaesthesia (AS/NZS 4375. 1996).
Wellington: Standards New Zealand,
1996.
10 Anon. Standard specification for user
applied drug labels in anesthesiology
(D4774±94). Philadelphia: American
Society for Testing and Materials,
1995.
11 Anon. Standard for user-applied drug
labels in anaesthesia and critical care
(Z264.3±98). Etobicoke. Ontario:
Canadian Standards Association, 1998.
Paradoxical emboli in patent
foramen ovale
A 77-year-old man who was scheduled
for a total hip replacement was referred
to me for a pre-operative anaesthetic
assessment because he had had a pacemaker inserted for complete heart block
two years previously. The cardiologist
who implanted the pacemaker had
echocardiographically diagnosed a
1-cm ostium secundum atrial septal
defect with left to right shunting. I
was concerned that during the reaming
and cementation of the femoral shaft,
emboli of air, fat or other debris released
q 2000 Blackwell Science Ltd
Anaesthesia, 2000, 55, pages 590±619
Correspondence
................................................................................................................................................................................................................................................
into the venous system could, if the
shunt was reversed, produce paradoxical
emboli in the heart, brain and kidneys
and other organs.
Pell et al. have graphically demonstrated such a possibility occurring when
using transoesophageal echocardiography
during a total hip replacement [1].
Echogenic material was seen entering
the right side of the heart, and as right
heart and pulmonary artery pressures
increased, as well as the pulmonary
vascular resistance in response to multiple episodes of pulmonary embolisation,
the shunt reversed and the echogenic
material passed through the foramen
ovale into the left side of the heart with
disastrous consequences for the patient.
As the operation was elective, my
patient was referred for cardiological
opinion. Operative device closure of the
ASD before hip replacement was
advised.
The foramen ovale is patent in 20±
34% of people [2]. Obviously many
patients with unrecognised ASD have
undergone joint replacement uneventfully. If, however, an ASD is demonstrated before surgery, should such
measures as button closure of the
defect be routinely undertaken preoperatively?
W. O. Roberts
Ysbyty Gwynedd,
Bangor LL57 2PW, UK
References
1 Pell ACH, Hughes D, Keating J,
Christie J, Busitil A, Sutherland GR.
Fulminating fat embolism caused by
paradoxical embolism through a patent
q 2000 Blackwell Science Ltd
foramen ovale. New England Journal of
Medicine 1993; 329: 926±9.
2 Hagen PT, Scholz DG, Edwards WD.
Incidence and size of patent foramen
ovale during the first 10 decades of life:
an autopsy study of 965 normal hearts.
Mayo Clinic Proceedings 1984; 59: 17±20.
How to skin a bearded cat
We note with interest the response to
our original letter (Anaesthesia 1998; 53:
1034±5), in which we described the use
of cling film to rescue the bearded
airway. There were concerns expressed
over the safety of our suggestion [1, 2]
and we agree with many of these issues.
Mummification of the patient with
cling film is not, however, what we
described or suggested. The cling film
should be applied so that it covers the
patient's face and not the neck. It is then
still possible to apply cricoid pressure
and avoid venous occlusion. At the time
of laryngoscopy the cellophane can be
split free and therefore mandibular
subluxation is not compromised.
There were also concerns that the
time spent applying the cling film
would lead to hypoxia [2]. The situation
was that of a difficult airway when
adequate oxygenation could not be
achieved. Time spent trimming the
patients beard might not be any shorter.
Obviously, in-line cervical spine immobilisation should always be applied in
the trauma situation and we would not
recommend the use of cling film when
the stability of the cervical spine is in
doubt. The unconscious trauma victim
described in our original letter was a
burns patient and cervical spine injury,
from the history, was not an issue.
In the responses several alternative
suggestions were made on how to
manage the bearded airway. These
included a defibrillator pad with a hole
cut in the centre [2, 3]; a laryngeal mask
[2, 4]; the eversion of the lower lip on
which to place the face mask rim [5]; a
rapid sequence induction [2]; and finally
the impromptu beard trimming [1]
(assuming an NHS razor is both sharp
and available and that there is time
enough for a shave).
Finally, we reported this following a
single episode and accept that it doesn't
bear medical scrutiny. It may be useful
in a situation involving a bearded
patient who would prefer his or her
whiskers left intact. Nevertheless, we
accept that cling film should appear at
the bottom of the list of intervention
measures but there is more than one
way to skin a cat. To this end we have
recruited a willing feline and a brand
new role of cling film.
W. Ames
University of Michigan Medical
Center,
MI 48109±0048, USA
References
1 Moore EW, Cowan CM. A close shave.
Anaesthesia 1999; 54: 305.
2 Hancock AC. The bearded airway.
Anaesthesia 1999; 54: 408.
3 Thomas DI. Overcoming the beard.
Anaesthesia 1999; 54: 100.
4 Alexander R. Overcoming the beard.
Anaesthesia 1999; 54: 100.
5 Crooke J. The bearded airway.
Anaesthesia 1999; 54: 500.
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