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Research Interests:
To design and validate a practical questionnaire for clinicians, to identify barriers and facilitators for Evidence Based Practice (EBP), i.e. the use of research evidence in patient care. The inventory is ultimately intended for... more
To design and validate a practical questionnaire for clinicians, to identify barriers and facilitators for Evidence Based Practice (EBP), i.e. the use of research evidence in patient care. The inventory is ultimately intended for departments to assess local conditions for EBP, to aim and evaluate efforts at improving or maximizing EBP. We derived candidate items from existing EBP scales, psychology and behavioural economics. In an online Delphi study, 537 international expert clinicians, researchers, teachers and policymakers interested in EBP identified items with sufficient face and content validity. We piloted and validated the resulting draft Inventory among 127 clinicians from various specialties and career stages. The Delphi study started with 114 items and resulted in a draft Inventory with 29 items in 5 dimensions. During the pilot the inventory was easy to complete within 15 minutes and the items showed sufficient response variation. In 4 of 5 dimensions test-retest reliabi...
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Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also... more
Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also been injected intrathecally in patients suffering from postherpetic neuralgia and complex regional pain syndrome. The reports on efficacy of intrathecal administration of MPA in neuropathic pain patients are contradictory, and safety is debated. In this review, we broadly consider mechanisms whereby glucocorticoids exert their action on spinal cascades relevant to the pain arising after nerve injury and inflammation. We then focus on the characteristics of the actions of MPA in pharmacokinetics, efficacy, and safety when administered in the intrathecal space.
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To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after... more
To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery. Randomised trial with an additional prediction study within the two randomised groups. Three centres for heart surgery in the Netherlands. 281 patients, mean age 61 years. Participants were randomly assigned to off-pump or on-pump coronary bypass surgery. Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months. Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three mont...
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Many experimental studies in mammals, and increasingly also in primates, have shown that almost all anaesthetic agents when administered during a young animal's brain-development phase cause increased neuroapoptosis and changes in... more
Many experimental studies in mammals, and increasingly also in primates, have shown that almost all anaesthetic agents when administered during a young animal's brain-development phase cause increased neuroapoptosis and changes in dendritic morphology at short term, and later, learning disorders. These findings are being confirmed in increasing numbers of retrospective cohort studies in humans. However, these retrospective cohort studies are considerably influenced by confounding. A current prospective randomized clinical trial comparing general and locoregional (spinal) anaesthesia for hernia repair could provide some clinical evidence. These study results will only provide information on relatively short procedures and will not be available until the first reliable neuropsychological evaluation at age 5 in 2018. Pending this additional data, we should discuss with our surgical colleagues the indications, timing and duration of surgery and - if possible - postpone elective surg...
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In older patients undergoing elective cardiac surgery, the timely identification and preparation of patients at risk for frequent postoperative hospital complications provide opportunities to reduce the risk of these complications. We... more
In older patients undergoing elective cardiac surgery, the timely identification and preparation of patients at risk for frequent postoperative hospital complications provide opportunities to reduce the risk of these complications. We developed an evidence-based, multi-component nursing intervention (Prevention of Decline in Older Cardiac Surgery Patients; the PREDOCS programme) for application in the preadmission period to improve patients' physical and psychosocial condition to reduce their risk of postoperative complications. This paper describes in detail the process used to design and develop this multi-component intervention. In a team of researchers, experts, cardiac surgeons, registered cardiac surgery nurses, and patients, the revised guidelines for developing and evaluating complex interventions of the Medical Research Council (MRC) were followed, including identifying existing evidence, identifying and developing theory and modelling the process and outcomes. Addition...
Research Interests: Program Evaluation, Nursing, Evidence Based Medicine, Survival Analysis, Medicine, and 15 moreHumans, Biomedical Research, Program Development, Female, Male, Netherlands, Intervention Studies, Patient Care Team, Public health systems and services research, Geriatric Assessment, Interdisciplinary Communication, Nursing Assessment, Postoperative Complications, Frail elderly, and Cardiovascular medicine and haematology
Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting older patients. The use of cardiopulmonary bypass is a suspected cause. Research into pathophysiology and possible preventive measures... more
Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting older patients. The use of cardiopulmonary bypass is a suspected cause. Research into pathophysiology and possible preventive measures requires the use of an animal model. Commercial oxygenators are too large and expensive for use in small animals. We describe a fiber oxygenator scaled for use in the rat. In vitro and in vivo testing show that it is able to support full gas exchange in this size of animal, and causes no allergic or toxic reactions.
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ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following non-cardiac and non-neurosurgical procedures. Nested patient-control study. From January 2002-June 2009, all patients at UMC Utrecht who had... more
ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following non-cardiac and non-neurosurgical procedures. Nested patient-control study. From January 2002-June 2009, all patients at UMC Utrecht who had a stroke within 10 days of undergoing a non-cardiac or non-neurosurgical procedure were matched with 6 control patients of the same age who underwent the same procedure but had no stroke. A total of 42 patients who suffered postoperative stroke (0.09%) were included. After correction for potential confounders, the length of time that the mean blood pressure remained more than 30% lower than baseline was statistically significantly associated with the occurrence of a postoperative stroke. Intraoperative hypotension may play a role in the development of postoperative ischaemic stroke.
Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lower limb neurological deficits. Spinal cord monitoring can only improve outcome if ischemia is detected before irreversible damage has... more
Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lower limb neurological deficits. Spinal cord monitoring can only improve outcome if ischemia is detected before irreversible damage has occurred and protective measures are readily available. Monitorin( spinal cord function with motor evoked potentials (MEPs) is a relatively new technique. With MEP. recorded from the muscle (myogenic MEPs), the vulnerable spinal motoneuronal system is exclusively monitored and ischemia is detected within minutes. Using a strategy aimed at maintaining and restoring spinal cord blood supply (distal aortic perfusion, sequential aortic clamping, and selective segmental artery reattachment), early detection of ischemia allows protective measures to be applied and adjusted immediately, ie, reattaching or safely ligating intercostal arteries, increasing proximal o distal aortic pressures as required, or inducing hypothermia. Recent improvements in the technique fo eliciting myogenic MEPs include multi-pulse stimulation paradigms and the use of a circumferentia cathode. This results in robust and reproducible signals, which are less susceptible to anesthetic interference and allow the use of a constant level of neuromuscular blockade. In conclusion, monitoring myogenic MEPs during a TAA repair has become clinically feasible. The fast detection of spinal cord ischemia allows timely guidance of protective measures.
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Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infectious diseases. Several case fatalities have occurred with this form of treatment, but most were attributable to systemic complications... more
Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infectious diseases. Several case fatalities have occurred with this form of treatment, but most were attributable to systemic complications rather than central nervous system toxicity. Nonetheless, demyelating peripheral neuropathy and neurological symptoms of nausea, delirium, apathy, stupor, and coma have been reported. Temperatures exceeding 40 degrees C cause transient vasoparalysis in humans, resulting in cerebral metabolic uncoupling and loss of pressure-flow autoregulation. These findings may be related to the development of brain edema, intracerebral hemorrhage, and intracranial hypertension observed after prolonged therapeutic hyperthermia. Furthermore, deliberate hyperthermia critically worsens the extent of histopathological damage in animal models of traumatic, ischemic, and hypoxic brain injury. However, it is unknown whether these findings translate to episodes of spontaneous fever in neurologically injured patients. In a clinical setting fever is a strong prognostic marker of a patient's primary degree of neuronal damage, and a causal relation with long-term functional neurological outcome has not been established for most types of brain injury. Furthermore, in the neurosurgical intensive-care unit fever is extremely common whereas antipyretic therapy is only poorly effective. Therefore maintaining strict normothermia may be an impossible goal in many patients. Although there are several physiological arguments for avoiding exogenous hyperthermia in neurologically injured patients, there is no evidence that aggressive attempts at controlling spontaneous fever can improve clinical outcome.
Research Interests: Cognitive Science, Neurology, Humans, Outcome, Cerebral Cortex, and 14 moreInfectious Disease, Central Nervous System, Animal Model, Brain injury, Body Temperature, Intensive Care Unit, Peripheral Neuropathy, Metabolic rate, Fever, Intracerebral Hemorrhage, Cerebral Blood Flow, Neurosciences, Brain Edema, and Cerebral autoregulation
High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major... more
High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major clinical outcomes. The objective of this meta-analysis was to estimate the effect of prophylactic corticosteroids in cardiac surgery on mortality, cardiac and pulmonary complications. Major medical databases (CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched for randomised studies assessing the effect of corticosteroids in adult cardiac surgery. Database were searched for the full period covered, up to December 2009. No language restrictions were applied. Randomised controlled trials comparing corticosteroid treatment to either placebo treatment or no treatment in adult cardiac surgery were selected. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more end-points. The processes of searching and selection for inclusion eligibility were performed independently by two authors. Also, quality assessment and data-extraction of selected studies were independently performed by two authors. The primary endpoints were mortality, cardiac and pulmonary complications. The main effect measure was the Peto odds ratio comparing corticosteroids to no treatment/placebo. Fifty-four randomised studies, mostly of limited quality, were included. Altogether, 3615 patients were included in these studies. The pooled odds ratio for mortality was 1.12 (95% CI 0.65 to 1.92), showing no mortality reduction in patients treated with corticosteroids. The odds ratios for myocardial and pulmonary complications were 0.95, (95% CI 0.57 to 1.60) and 0.83 (95% CI 0.49 to 1.40), respectively. The use of a random effects model did not substantially influence study results. Analyses of secondary endpoints showed a reduction of atrial fibrillation and an increase in gastrointestinal bleeding in the corticosteroids group. This meta-analysis showed no beneficial effect of corticosteroid use on mortality, cardiac and pulmonary complications in cardiac surgery patients.
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Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster (HZ) and difficult to treat. Timely identification of high-risk HZ-patients enables physicians to focus on PHN prevention. To assess which simple to measure... more
Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster (HZ) and difficult to treat. Timely identification of high-risk HZ-patients enables physicians to focus on PHN prevention. To assess which simple to measure factors are independent predictors of PHN, and whether psychosocial and serological/virological parameters have additional predictive value, a prospective cohort study in primary care was conducted. We included 598 elderly (>50 years) consecutive patients with acute HZ (rash <7 days) below sixth cervical dermatome. At baseline demographic, clinical (e.g., duration and severity of pain and rash), psychological (Pain Cognition List [PCL] and Spielberger's Anxiety Inventory), serological (VZV-antibodies) and virological (viremia presence) variables were measured. Blood tests were performed in a random subset of 218 patients. Primary outcome was significant pain (VAS >30 on 0-100 scale) after three months. The final prediction model obtained from multivariable logistic regression was (internally) validated using bootstrapping techniques, and adjusted for optimism. Forty-six (7.7%) patients developed PHN. Independent predictors were age (odds ratio [OR]=1.08 per year), acute pain severity (OR=1.02 per unit), presence of severe rash (OR=2.31), and rash duration before consultation (OR=0.78 per day): area under receiver-operating-characteristic curve [ROC area]=0.77 (95% CI: 0.71-0.82). Of the five PCL scores, only factor V ('trust in healthcare') was an additional predictor (OR=1.01 per unit), though it increased the ROC area with only 0.01 to 0.78. The Spielberger's anxiety scores and serological and virological variables were no additional predictors. Thus, four simple variables can help physicians to timely identify elderly HZ-patients at risk of PHN.
Research Interests: Pain, Aging, Logistic Regression, Humans, Female, and 15 moreMale, Cohort Study, Prediction Model, Aged, Middle Aged, Age Factors, Disease Progression, Herpes Zoster, Pain Measurement, Logistic Models, Pain Threshold, Cohort Studies, Neuropsychological Tests, High risk, and Medical and Health Sciences
Background. When planning to use a validated prediction model in new patients, adequate performance is not guaranteed. For example, changes in clinical practice over time or a different case mix than the original validation population may... more
Background. When planning to use a validated prediction model in new patients, adequate performance is not guaranteed. For example, changes in clinical practice over time or a different case mix than the original validation population may result in inaccurate risk predictions. Objective. To demonstrate how clinical information can direct updating a prediction model and development of a strategy for handling missing predictor values in clinical practice. Methods. A previously derived and validated prediction model for postoperative nausea and vomiting was updated using a data set of 1847 patients. The update consisted of 1) changing the definition of an existing predictor, 2) reestimating the regression coefficient of a predictor, and 3) adding a new predictor to the model. The updated model was then validated in a new series of 3822 patients. Furthermore, several imputation models were considered to handle real-time missing values, so that possible missing predictor values could be ...
Research Interests: Geography, Decision Making, Risk assessment, Medicine, Applied Economics, and 13 moreMedical Decision Making, Humans, Female, Male, Confidence intervals, ROC Curve, Middle Aged, Public health systems and services research, Risk Assessment, Clinical Decision Support Systems, Logistic Models, Predictive value of tests, and Organizational case studies
During thoracoabdominal aortic aneurysm repair, a prolonged interruption of the spinal cord blood supply can result in irreversible spinal cord damage. The aim of this study was to investigate whether selective segmental artery perfusion... more
During thoracoabdominal aortic aneurysm repair, a prolonged interruption of the spinal cord blood supply can result in irreversible spinal cord damage. The aim of this study was to investigate whether selective segmental artery perfusion during aortic clamping could prevent paraplegia in pigs. Specially designed segmental artery perfusion catheters, which could be attached to an extracorporeal bypass graft system, were used. In experiment I (n = 10), it was assessed whether selective segmental artery perfusion could reverse electrophysiologic evidence of spinal cord ischemia and maintain transcranial motor evoked potentials (tc-MEPs) during 60 minutes of aortic cross-clamping. The abdominal aorta, containing critical segmental arteries, was bypassed through use of an aortoaortic bypass graft system. After the disappearance of tc-MEPs, an aortotomy was followed by selective segmental artery perfusion. In experiment II (n = 10), the aim was to determine whether selective segmental artery perfusion could prevent paraplegia. In five animals (group A), aortic cross-clamping was followed by selective segmental artery perfusion; five control animals (group B) underwent segmental artery blockade only. Postoperative hind limb function and spinal cord histopathology were evaluated on the third postoperative day. In experiment I, tc-MEPs disappeared within 3.7 +/- 3.7 minutes after cross-clamping and returned in all animals in 8.5 +/- 5.3 minutes after selective perfusion. During the study period, tc-MEP amplitudes recovered to a median of 49% (range, 28%-113%) of baseline values. Total bypass graft flow was 880 +/- 294 mL/min, of which 184 +/- 54 mL/min was directed to the selective perfusion catheters. The flow in individual catheters was 52 +/- 13 mL/min. In experiment II, all perfused animals demonstrated normal hind limb function, whereas four of five control animals were paraplegic on day 3 (P =.04) In the perfused animals, histopathologic examination showed either no spinal cord damage or eosinophilic neurons only, whereas in paraplegic controls there was infarction in large areas of the cord (P <.0001). In pigs, selective segmental artery perfusion can provide sufficient spinal cord blood flow to prevent paraplegia resulting from 60 minutes of aortic clamping, as shown by clinical outcomes and histopathologic examination.
Research Interests: Surgery, Medicine, Prevention, Paraplegia, Complication, and 15 moreIschemia, Female, Animals, Spinal Cord, Perfusion, Motor Evoked Potentials, Blood Flow, Extracorporeal Circulation, Aorta, Selectivity, Motor evoked potential, Constriction, Abdominal Aorta, Intraoperative complications, and Medical and Health Sciences
Research Interests: Medicine, Western blotting, Paraplegia, Animals, Spinal Cord, and 12 moreThe, Clinical Sciences, Time Factors, Western blot, Heat Shock Proteins, Heat Shock Protein, Rabbits, Preconditioning, Ischemic Preconditioning, Control Group, Thoracic and cardiovascular surgery, and Cardiovascular medicine and haematology
The acute and subchronic effects of low doses nocturnally administered amitriptyline were compared to placebo in a double-blind crossover randomized study on driving ability and driving-related skills involving seven chronic neuropathic... more
The acute and subchronic effects of low doses nocturnally administered amitriptyline were compared to placebo in a double-blind crossover randomized study on driving ability and driving-related skills involving seven chronic neuropathic pain patients. Performance testing occurred at the first and last day of each 15-day drug administration period, which was preceded by a 6-day washout phase. A standardized method of measuring driving ability, the on-the-road driving test, was performed on all visits. Patients were instructed to drive with a steady lateral position while maintaining a constant speed of 95km/h. The primary outcome of the driving test is the Standard Deviation of Lateral Position (SDLP, cm), which is an index of weaving of the car. At the first treatment day, driving performance was significantly impaired in patients after nocturnal administration of 25mg amitriptyline compared to placebo. The increase in SDLP of 3cm was higher than the increment generally observed wit...
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Can we learn anything meaningful about disease and causation without direct access to patient records? John Snow, the 18th century father of both Anesthesiology and Epidemiology did just that when he plotted cases of cholera on a map in... more
Can we learn anything meaningful about disease and causation without direct access to patient records? John Snow, the 18th century father of both Anesthesiology and Epidemiology did just that when he plotted cases of cholera on a map in 1854 and discovered that the disease was not caused by waves of bad air (‘‘miasma’’) coming from the river Thames, but was transmitted by drinking water from a sewagecontaminated well on Broad Street in London. John Snow made his classic discovery without having seen a Vibrio Cholerae specimen through a microscope. In fact, the bacterial cause of cholera was only identified 30 years later during an outbreak in Calcutta. In the same year that Snow was able to eradicate cholera without knowledge of its microbial pathology, a nurse working in a field hospital during the Crimean War, Florence Nightingale, was able to reduce an appalling hospital mortality rate of over 30%—10 times more soldiers died of infectious diseases than died of their war wounds—to less than 2% by radically improving sanitary conditions. Again, no deep knowledge of microbiology was involved. Both Florence Nightingale and John Snow were completely unaware of the microbial cause of high mortality. Both are now regarded as pioneers of epidemiology and medical statistics, because they preferred the use of counting, simple mathematics, and graphing results over ‘‘learned intuition’’ and belief or what we would now call ‘‘eminence-based medicine.’’ This not only allowed them to draw inferences about causation but also to convince policy makers of their day that radical change was needed. In this issue of J Neurosurg Anesthesiol, DiMaggio and colleagues address the growing concern that exposure to anesthetic drugs during a vulnerable period in the development of the human nervous system may result in neurodegeneration and increase the probability of cognitive and behavioral abnormalities later in life. Although the evidence from laboratory studies is increasing, clinical data are sorely lacking and all we have available at the moment is retrospective data tucked away in many different types of hospital and governmental databases. DiMaggio and colleagues used a typical ‘‘John Snow’’ approach, analyzing only government databases to address the question whether exposure to anesthesia and surgery associates with evidence of neurotoxicity. A cohort of underprivileged children born in the state of New York from parents who were covered under the Medicaid system was selected and the databases were queried both for outcome (delayed development, behavioral disorder, language or speech problems, mental retardation, or a psychiatric diagnosis such as autism) and determinants (an operation for herniorrhaphy within the first 4 years of life and a set of demographic and perinatal data). They then calculated the probability of disturbed neurocognitive development as a function of exposure to herniorrhaphy and a series of other possible determinants. As this is really an ‘‘etiologic’’ question, all determinants other than being exposed to hernia surgery were potential confounders. Epidemiologists intent on uncovering causation often spend a lifetime trying to correct for all possible sources of confounding. Of course, the sobering reality in this clinical domain is that it is simply impossible to account for all possible confounders, because many are either not recorded or because they have not (yet) been considered.
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Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered... more
Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered because most anesthetic regimens result in severe depression of tcmag-MER amplitudes. As part of our systematic attempts to identify anesthetic agents and supplements suitable for use during tcmag-MER recording, we studied the effect of bolus doses of pentobarbital (1.5 mg/kg), droperidol (0.07 mg/kg), or ketamine (1 mg/kg), administered intravenously, on compound muscle action potentials to transcranial magnetic stimulation in five healthy volunteers. The doses were chosen to be comparable with doses that might be suitable for supplementation of a nitrous oxide/opioid anesthetic technique. Droperidol administration resulted in sustained amplitude depression of both tibialis and adductor pollicis tc-MERs to 30 +/- 9% and 39 +/- 14% of baseline (P < 0.01). Tcmag-MER amplitude changes after pentobarbital were variable, ranging from no change to substantial amplitude depression (to 20% of baseline) in two subjects. In contrast, ketamine administration did not result in significant amplitude depression. In three subjects, tibialis anterior amplitude increased to 150 to 220% of control values in the first 10 minutes after ketamine. Onset latency was unchanged after any drug. These data indicate that tcmag-MERs are moderately depressed after droperidol and pentobarbital but well preserved after ketamine. Ketamine may be a more suitable supplement to opioid/nitrous oxide anesthesia than droperidol or pentobarbital.
Research Interests: Psychology, Neurosurgery, Skeletal muscle biology, Medicine, Evoked Potentials, and 14 moreHumans, Male, Reaction Time, Ketamine, Electromagnetic Fields, Motor Cortex, Synaptic Transmission, Clinical Sciences, General Anesthesia, Adult, Neurosciences, Intraoperative Neurophysiological Monitoring, Pentobarbital, and Motor Neurons
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To investigate the association between the use of a selective serotonin reuptake inhibitor (SSRI) and the occurrence of QT interval prolongation in an elderly surgical population. A cross-sectional study was conducted among patients... more
To investigate the association between the use of a selective serotonin reuptake inhibitor (SSRI) and the occurrence of QT interval prolongation in an elderly surgical population. A cross-sectional study was conducted among patients (> 60 years) scheduled for outpatient preanesthesia evaluation in the period 2007 until 2012. The index group included elderly users of an SSRI. The reference group of nonusers of antidepressants was matched to the index group on sex and year of scheduled surgery (ratio, 1:1). The primary outcome was the occurrence of QT interval prolongation shown on electrocardiogram. The QT interval was corrected for heart rate (QTc interval). The secondary outcome was the duration of the QTc interval. The outcomes were adjusted for confounding by using regression techniques. The index and reference groups included 397 users of an SSRI and 397 nonusers, respectively. QTc interval prolongation occurred in 25 (6%) and 19 (5%) index and reference patients, respectively. After adjustment for confounding, users of an SSRI did not have a higher risk for QTc interval prolongation compared to nonusers: OR = 1.1 (95% CI, 0.5 to 2.0). The adjusted mean QTc interval length in users of an SSRI and nonusers was comparable (difference of 1.5 milliseconds [95% CI, -1.8 to 4.8]). Use of the most frequently used SSRIs citalopram and paroxetine was not associated with a higher risk of QTc interval prolongation nor with lengthening of the QTc interval duration. The use of an SSRI by elderly surgical patients was not associated with the occurrence of QT interval prolongation.
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To measure the diagnostic value of the Numeric Rating Scale by comparing it to a Verbal Rating Scale in older patients. Pain management in older patients is an important challenge because of their greater susceptibility to adverse effects... more
To measure the diagnostic value of the Numeric Rating Scale by comparing it to a Verbal Rating Scale in older patients. Pain management in older patients is an important challenge because of their greater susceptibility to adverse effects of analgesics. Nurses play an important role in applying guidelines for postoperative pain treatment. However, effective pain management is dependent upon valid and reliable pain assessment. Cross-sectional study. In total, 2674 older patients scored their postoperative pain on an 11-point numeric rating scale (NRS) and an adjective scale (VRS) including no pain, little pain, painful but bearable, considerable pain and terrible pain. The diagnostic value of different NRS cut-off values for administering analgesics is determined by an ROC curve. Sensitivity of NRS > 3 for 'unbearable' pain in older patients was 72% with a specificity of 97·2%. With a cut-off point NRS > 4, sensitivity increased to 83%, while specificity was 96·7%. With a cut-off point NRS > 5, sensitivity was 94%, while specificity was 85%. A high proportion (75%) of older old patients (≥ 75 years) with 'painful but bearable' considers NRS 4, 5 and 6 to this VRS category. Using an NRS cut-off point > 3 or > 4, a large group of older patients with 'bearable' pain would incorrectly classified as 'unbearable'. When we make the assumption that bearable pain means no wish for additional analgesics, this misclassification might result in overtreatment with analgesics, while 3% would be undertreated. With NRS cut-off point > 5, 6% have a risk of overtreatment and 15% of undertreatment. Nurses should not rely solely on the NRS score in determining pain treatment; they need to communicate with older patients about their pain, the need for analgesics and eventual misconceptions about analgesics.
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... Cor J Kalkman, MD: Affiliations. ... Address reprint requests to Cor J. Kalkman, MD, Department of Anesthesiology, Division of Perioperative Care and Emergency Medicine, University Medical Center, Utrecht, the Netherlands. email... more
... Cor J Kalkman, MD: Affiliations. ... Address reprint requests to Cor J. Kalkman, MD, Department of Anesthesiology, Division of Perioperative Care and Emergency Medicine, University Medical Center, Utrecht, the Netherlands. email address. ...
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Research Interests: Primary Care, General Practice, Family, Family Practice, Logistic Regression, and 15 moreHumans, Female, Male, Netherlands, Aged, Middle Aged, Adult, Public health systems and services research, Herpes Zoster, Medical Records, Logistic Models, Antiviral Agents, Guideline Adherence, National Survey, and Antiviral Therapy
In humans, damage to the nervous system can lead to a pain state referred to as neuropathic pain. Here, we give a short overview of the clinical picture and classification of neuropathic pain and highlight some of the currently known... more
In humans, damage to the nervous system can lead to a pain state referred to as neuropathic pain. Here, we give a short overview of the clinical picture and classification of neuropathic pain and highlight some of the currently known pathophysiological mechanisms involved, with special emphasis on neuropeptide plasticity. In this context, we discuss a specific group of neuropeptides, the melanocortins. These peptides have been demonstrated to play a role in nociception and to functionally interact with the opiate system. Recently, we demonstrated that spinal melanocortin receptors are upregulated in a rat model of neuropathic pain and that blockade of the melanocortin MC(4) receptor has anti-allodynic effects in this condition, suggesting that the melanocortin system plays a role in neuropathic pain. A natural agonist of melanocortin receptors is alpha-melanocyte-stimulating hormone (alpha-MSH), derived from the precursor molecule pro-opiomelanocortin (POMC). Cleavage of this precursor also yields beta-endorphin, which is co-released with alpha-MSH in nociception-associated areas of the spinal cord. We hypothesise that melanocortin receptor blockade attenuates a tonic influence of alpha-MSH on nociception, thus allowing the analgesic effects of beta-endorphin to develop, resulting in the alleviation of allodynia. In this way, treatment with melanocortin receptor antagonists might enhance opioid efficacy in neuropathic pain, which would be of great benefit in clinical practice.
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Introduction. This study aims to evaluate for the first time the value of visualizing veins by a prototype of a near-infrared (NIR) vascular imaging system for venipuncture in children. Methods. An observational feasibility study of... more
Introduction. This study aims to evaluate for the first time the value of visualizing veins by a prototype of a near-infrared (NIR) vascular imaging system for venipuncture in children. Methods. An observational feasibility study of venipunctures in children (0-6 years) attending the clinical laboratory of a pediatric university hospital during a period of 2 months without (n = 80) and subsequently during a period of 1 month with a prototype of an NIR vascular imaging system (n = 45) was conducted. Failure rate (ie, more than 1 puncture) and time of needle manipulation were determined. Results. With the NIR vascular imaging system, failure rate decreased from 10/80 to 1/45 ( P = .05) and time decreased from 2 seconds (1-10) to 1 second (1-4, P = .07). Conclusion . This study showed promising results on the value of an NIR vascular imaging system in facilitating venipunctures.
Research Interests: Near Infrared, Medicine, Feasibility Study, Observation, Humans, and 15 moreChild, Female, Male, Infant, Diagnostic Imaging, Newborn Infant, Infrared, Infrared Rays, Clinical Nutrition in Pediatrics, Child preschool, Failure rate, imaging system, Blood Specimen Collection, Clinical Pediatrics, and Paediatrics and reproductive medicine
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... View: Abstract. A246, Use of TSE "Mask" by Non-Anesthesiologists To Improve Oxygenation of High-Risk Patients during TEE. ** James Tse, MD, Ph.D., Sylviana Barsoum, MD, Sal Zisa, MD, Mary Corless, RN, Shaul Cohen, MD. ...
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Regional spinal cord cooling can increase the tolerable duration for spinal cord ischemia resulting from aortic clamping. We compared the efficacy of epidural and subdural cooling and the effect of the resulting cerebrospinal... more
Regional spinal cord cooling can increase the tolerable duration for spinal cord ischemia resulting from aortic clamping. We compared the efficacy of epidural and subdural cooling and the effect of the resulting cerebrospinal fluid-pressure (CSF) increases on spinal cord motor neuron function. In 8 pigs, CSF temperature and pressure were assessed in the subdural space at L4, T15, and T7. Saline was infused at 333, 666, and 999 ml/h at four consecutive locations: L4 subdural, L4 epidural, T15 subdural, and T15 epidural. First, the influence of CSF-pressure increases during normothermic infusion on transcranial motor evoked potentials (tc-MEPs) was assessed. Then, hypothermic infusion (4 degrees C) was performed to assess CSF-temperature changes. During normothermic infusion, baseline CSF pressures increased uniformly from 6 +/- 4 mm Hg to 34 +/- 18, 42 +/- 17, and 50 +/- 18 mm Hg with increasing infusion rates (p < 0.001), and did not differ between epidural or subdural infusion. Tc-MEPs indicated spinal cord ischemia in 6 animals when CSF pressures reached 65 +/- 11 mm Hg. During hypothermic infusion, CSF temperatures decreased from 37 degrees to 35 +/- 1.2 degrees, 31 +/- 2.2 degrees, and 28 +/- 2.8 degrees C, but increasing CSF-temperature gradients were observed between the infusion location and distant segments. Subdural cooling resulted in lower CSF temperatures (p < 0.001), but caused larger CSF-pressure increases (p < 0.001). Subdural and epidural infusion cooling produce localized spinal cord hypothermia in pigs. The concurrent pressure increases, however, are uniformly distributed and can result in tc-MEP evidence of ischemia.
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Background To assess the incidence of postoperative nausea and vomiting after total intravenous anesthesia (TIVA) with propofol versus inhalational anesthesia with isoflurane-nitrous oxide, the authors performed a randomized trial in... more
Background To assess the incidence of postoperative nausea and vomiting after total intravenous anesthesia (TIVA) with propofol versus inhalational anesthesia with isoflurane-nitrous oxide, the authors performed a randomized trial in 2,010 unselected surgical patients in a Dutch academic institution. An economic evaluation was also performed. Methods Elective inpatients (1,447) and outpatients (563) were randomly assigned to inhalational anesthesia with isoflurane-nitrous oxide or TIVA with propofol-air. Cumulative incidence of postoperative nausea and vomiting was recorded for 72 h by blinded observers. Cost data of anesthetics, antiemetics, disposables, and equipment were collected. Cost differences caused by duration of postanesthesia care unit stay and hospitalization were analyzed. Results Total intravenous anesthesia reduced the absolute risk of postoperative nausea and vomiting up to 72 h by 15% among inpatients (from 61% to 46%, P < 0.001) and by 18% among outpatients (fr...
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Background: Clinical prediction models have been shown to have moderate sensitivity and specificity, yet their use will depend on implementation in clinical practice. The authors hypothesized that implementation of a prediction model for... more
Background: Clinical prediction models have been shown to have moderate sensitivity and specificity, yet their use will depend on implementation in clinical practice. The authors hypothesized that implementation of a prediction model for postoperative nausea and vomiting (PONV) would lower the PONV incidence by stimulating anesthesiologists to administer more “risk-tailored” prophylaxis to patients. Methods: A single-center, cluster-randomized trial was performed in 12,032 elective surgical patients receiving anesthesia from 79 anesthesiologists. Anesthesiologists were randomized to either exposure or nonexposure to automated risk calculations for PONV (without patient-specific recommendations on prophylactic antiemetics). Anesthesiologists who treated less than 50 enrolled patients were excluded during the analysis to avoid too small clusters, yielding 11,613 patients and 57 anesthesiologists (intervention group: 5,471 and 31; care-as-usual group: 6,142 and 26). The 24-h incidence ...
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... Cor J. Kalkman, MD, was supported by grants from the Anesthesia Foundation of the University of California, San Diego; the Depart-ment of Neurosurgery of the University of California, San Diego; The Netherlands Organization for... more
... Cor J. Kalkman, MD, was supported by grants from the Anesthesia Foundation of the University of California, San Diego; the Depart-ment of Neurosurgery of the University of California, San Diego; The Netherlands Organization for Scientific Research; and the Depart-ment of ...
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Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid... more
Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was induced with i.v. etomidate 0.3 mg/kg and sufentanil 1.5 microg/kg and was maintained with sufentanil 0.5 microg x kg(-1) x h(-1) and N2O 50% in oxygen. Muscle relaxation was kept at 25% of control with i.v. vecuronium. Electrical stimulation was accomplished with a transcranial stimulator set at maximal output (1200 V). Magnetic transcranial stimulation was accomplished with a transcranial stimulator set at maximal output (2 T). Just before skin incision, triplicate responses to single stimuli with both modes of cortical stimulation were randomly recorded from the tibialis anterior muscles. Amplitudes and latencies were compared using the Wilcoxon signed rank test. Bilateral tc-MEP responses were obtained in every patient with electrical stimulation. Magnetic stimulation evoked only unilateral responses in two patients. With electrical stimulation, the median tc-MEP amplitude was 401 microV (range 145-1145 microV), and latency was 32.8 +/- 2.3 ms. With magnetic stimulation, the tc-MEP amplitude was 287 microV (range 64-506 microV) (P &lt; 0.05), and the latency was 34.7 +/- 2.1 ms (P &lt; 0.05). We conclude that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with those elicited by electrical transcranial stimulation. Transcranial motor evoked potentials are used to monitor spinal cord integrity intraoperatively. We compared the relative efficacy of electrical and magnetic transcranial stimuli in anesthetized patients. It seems that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with electrical transcranial stimulation.
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In a randomized, cross-over study, we prospectively compared the efficacy and quality of two methods to achieve conscious sedation with propofol in 11 unpremedicated, anxious dental patients. Each patient underwent two dental procedures,... more
In a randomized, cross-over study, we prospectively compared the efficacy and quality of two methods to achieve conscious sedation with propofol in 11 unpremedicated, anxious dental patients. Each patient underwent two dental procedures, one that was conducted under target-controlled infusion (TCI) by the anesthesiologist (ACS), and the other that used patient-controlled sedation (PCS). The initial target concentration in the ACS mode was 2.5 microg/mL, which was manipulated in both directions until the desired clinical end point was achieved. In the PCS mode, a 4-mg bolus of propofol (10 mg/mL) was delivered at each activation of the machine, infused over 7 s without a lockout interval. The anxious dental patients could induce and maintain conscious sedation with the PCS settings. The mean (range) venous blood propofol concentrations were not significantly different with either mode: ACS 1.8 (0.8-2.7) microg/mL and PCS 1.2 (0.2-2.5) microg/mL. The level of patient satisfaction, quality of sedation, and treatability were not different for either mode of sedation. The intensity of amnesia for intraoperative events was related to the blood concentrations achieved. In the ACS mode, one patient became unresponsive (sedation level 4) immediately after the start of sedation. No adverse cardiorespiratory effects resulted from either mode of propofol sedation. Five patients expressed a strong preference for PCS, and three would prefer ACS in the future. The results of the present study suggest that with these PCS settings, a satisfactory level of conscious sedation and a high level of patient satisfaction was achieved. In a randomized, cross-over study, the blood propofol concentrations necessary to achieve conscious sedation in anxious dental patients using a target-controlled infusion conducted by the anesthesiologist versus patient-controlled sedation were not different. With the patient-controlled sedation settings, a satisfactory level of conscious sedation and a high level of patient satisfaction were achieved.
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We studied the feasibility of recording motor evoked responses to transcranial electrical stimulation (tce-MERs) during partial neuromuscular blockade (NMB). In 11 patients, compound muscle action potentials were recorded from the... more
We studied the feasibility of recording motor evoked responses to transcranial electrical stimulation (tce-MERs) during partial neuromuscular blockade (NMB). In 11 patients, compound muscle action potentials were recorded from the tibialis anterior muscle in response to transcranial electrical stimulation during various levels of vecuronium-induced NMB. The level of NMB was assessed by accelerometry of the adductor pollicis muscle after train-of-four stimulation of the ulnar nerve. The compound muscle action potential was also recorded from the tibialis anterior muscle after direct stimulation of the peroneal nerve (M-response) as an alternative means of assessing the degree of NMB. In all patients, tce-MERs could be recorded reliably during anesthesia with N2O and a continuous infusion of sufentanil (0.5 micrograms.kg-1.h-1). An intact train-of-four was present in all patients, and the amplitude of the first twitch was recorded and designated as the control value. Before administration of vecuronium, the M-response amplitude was 9.6 +/- 3.6 (mean +/- SD) mV, and the tce-MER amplitude was 1.21 +/- 0.66 mV. Although administration of vecuronium (0.05 mg/kg) resulted in loss of the mechanical adductor pollicis response in 8 of the 11 patients, the M-response and the tce-MER remained recordable. Subsequently, during an infusion of vecuronium, adjusted to maintain one or two mechanical responses to train-of-four stimulation, the average M-response to peroneal nerve stimulation was 5.2 +/- 2.5 mV (53% of the control value), and tce-MER amplitude was 0.59 +/- 0.36 mV (59% of the control value).(ABSTRACT TRUNCATED AT 250 WORDS)