CE 2.5
HOURS
Continuing Education
Bedside Assessment of
Enteral Tube Placement:
Aligning Practice with Evidence
The auscultatory method has long been proven unreliable, but old habits
die hard.
OVERVIEW: Since the flexible Levin tube was introduced in
1921, enteral feeding has become ubiquitous. From the outset, nurses have been responsible for confirming the correct
placement of enteral feeding tubes prior to their use for alimentation or medication administration, but current nursing
practice doesn’t always reflect the best evidence. Although
research has established the inadequacy of auscultation to
determine proper tube placement, this method is still commonly practiced. The authors examine the research that’s
been conducted over the past 25 years and compare the
accumulated evidence with current practice, as reflected in a
convenience sample of 28 New England hospitals. In addition,
they evaluate various methods for assessing enteral feeding
tubes and make evidence-based practice recommendations.
Keywords: enteral feeding, enteral nutrition, feeding tube,
feeding tube assessment, tube placement
nteral feeding is superior to parenteral nutrition in maintaining intestinal structure and
function, is associated with fewer possible
complications, and is less costly.1 Generally, enteral
feeding tube insertion and maintenance (including
the verification of tube placement) are under the
purview of RNs, but current practice in this area is
seldom evidence based, and the consequences can
be deadly.
Even if a tube is correctly inserted and initial gastric placement is confirmed by X-ray, continued
E
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assessment is required. Vomiting, coughing, retching, or suctioning can cause the distal tip to migrate
upward into the esophagus or downward into the
duodenum. It’s also possible for a portion of the
tube to become coiled in the pharynx. The severity
of resulting complications depends on whether the
malpositioned tube has been used to deliver feedings or medication, but possible outcomes include
aspiration, pneumothorax, and sepsis.
A study of patients treated in an ICU between
1993 and 1995 found that 14 (nearly 2%) of 740
small-bore enteral feeding tubes were unintentionally placed in the tracheopulmonary system, causing
major complications in five patients, two of whom
died as a direct result—one from a tension pneumothorax and the other from sepsis precipitated by the
delivery of alimentary fluid into the pleural space.2
In 2004, a large-scale study found that 87 (2%) of
4,190 patients with a nasoenteric feeding tube had
the tube inadvertently placed in the bronchus.3 Thirtyfour (39%) of these had endotracheal tubes in place,
but the inflated cuffs didn’t protect the airway in
the nine patients who sustained a pneumothorax
when the rigid stylet perforated the lung. A fouryear review of small-bore nasogastric feeding tube
insertions in a 690-bed medical center in Philadelphia revealed that in 50 (2.4%) of 2,079 patients
with chest radiographic reports that mentioned
feeding tubes, the tubes had been positioned in the
pulmonary cavity.4
Risk, however, is not limited to respiratory complications. In an unusual case, a patient sustained a
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By Shellie Robin Simons, PhD, RN, and Lisa M. Abdallah, PhD, RN, CNE
Figure 1. Chest X-rays show a correctly positioned enteral feeding tube (left) and an enteral feeding tube inadvertently positioned in the lower lobe of the right lung and a resulting infiltrate (right). Images courtesy of the Pennsylvania Patient Safety Advisory.
cerebral hemorrhage after a nurse inadvertently inserted a nasogastric tube through the sphenoid sinus
into the lateral ventricle of her brain.5 To protect patients from such life-threatening errors, nurses need
to follow a consistently reliable procedure for placing
and assessing the placement of enteral feeding tubes.
ASSESSMENT AFTER BLIND INSERTION: A DECADES-OLD
CHALLENGE
Accounts differ as to when the nasogastric tube
was first used to deliver enteral feeding. Some say
the Italian surgeon Aquapendente used a silver nasogastric tube in the 1600s, while others attribute
the first use to John Hunter, who fed a patient using
a flexible, hollow leather nasogastric tube in 1790.6
Levin introduced a flexible, rubber nasogastric tube
in 1921,6 and since that time, nasogastric tubes made
of polyvinyl chloride, silicone, and polyurethane have
become available, with polyurethane and silicone preferred because they remain soft, flexible, and nonreactive over time.7 But such structural improvements
in enteral feeding tubes have not eliminated a major
challenge in their use: reliably assessing placement
after blind insertion.
A long history of discredited methods. From the
1930s through the 1960s, many clinicians assumed
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that if a feeding tube was blindly inserted into the
lungs, it would separate the vocal cords, preventing
vocalization. During this period, nursing textbooks
taught that feeding tube placement could be assessed
by asking the patient to speak or hum; if the patient
could do so, this was thought to indicate that the tube
was in the alimentary, rather than the respiratory,
tract.8, 9 This assumption was found to be untrue in
1983, when it was reported that a feeding tube inadvertently placed in the pleural space of an alert elderly man neither interrupted his speech nor caused
him to cough.10
Textbooks of this era also suggested placing the
end of the tube in water because it was believed that
tracheal insertion would cause bubbles to appear
in the water when the patient exhaled.8, 9 But the
absence of bubbling is not a reliable indicator of
gastric placement: if the feeding tube is kinked or
occluded by respiratory secretions, it will produce
no bubbles; likewise, air within the stomach may
produce bubbles when a tube is properly placed.11
During the 1980s, nurses were taught to assess
enteral tube placement by quickly injecting 10 to
20 mL of air into the tube while auscultating the
patient’s left upper abdominal quadrant.12 If the
tube was in the stomach, the air was expected to
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Table 1. Policies for Assessing Placement of Enteral Feeding Tubes at 28 New England Hospitals
Number of policies
incorporating method
Assessment methoda
a
b
c
Inject air while listening with a stethoscope for a whooshing sound below the
diaphragm as the air enters the stomach
17 b
Aspirate gastric contents
13
Confirm newly inserted nasogastric feeding tube by X-ray before feeding or
medication administration
12
Mark tube at the point of entry into the nares and measure length of the
tube’s visualized portion
9
Use at least two methods to verify tube placement before feeding or medication administration
9
Assess residual volume of gastric aspirate
9
Check pH of gastric aspirate
5c
Visually assess gastric aspirate
4
Consult current nursing textbook
4
No formal policy for assessing enteral feeding tubes in adult patients
4
Ask patient to hum or speak
1
Listen for crackling noise and feel for stream of air at end of tube
1
No formal policy for assessing enteral feeding tubes in adult or pediatric
patients
1
Test for glucose in sputum
1
Methods were not exclusive except as noted.
Four policies used this method as the sole means of assessing tube placement.
One policy used this method as the sole means of assessing tube placement.
enter the stomach without resistance, producing a
“loud whooshing sound,” whereas if the tube was
in a lung or the trachea, the air was expected to produce a muffled sound.12 The effectiveness of this
practice was called into question in 1990, when a
landmark study of 85 acutely ill adults found that
the auscultatory method correctly predicted feeding tube location in only 34.2% of cases, with some
degree of whooshing sounds being heard in all subjects.13 In another study, auscultation incorrectly
predicted that 15 of 16 tubes had been placed in
the stomach.14
Since that time, significant evidence supporting
the discontinuation of this practice has emerged.
Most nasogastric feeding tubes are small-bore tubes
that limit the amount of air that can be injected and
make it difficult to hear the whooshing sound, and
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normal bowel sounds may be misinterpreted as
evidence that the tube is properly placed.15 Furthermore, auscultation is unlikely to reveal a malpositioned tube because nurses rarely auscultate over
the lungs or the epigastrium to check the type and
proximity of sound, and few nurses have actually
heard the sound created by a malpositioned feeding tube.16, 17 Nevertheless, a 2002 survey of British
nurses who specialized in nutrition found that 26%
of the 47 respondents used auscultation alone to
confirm nasogastric tube placement after blind insertion.18
COMPARING RESEARCH AND CURRENT PRACTICE
To examine current practice regarding confirmation of enteral tube placement, we telephoned a
convenience sample of hospitals and skilled nursing
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facilities in Massachusetts and New Hampshire to
request a copy of their current policies and procedures for confirming placement of feeding tubes. A
total of 28 health care facilities agreed to share their
policies.
To compare these practices with recently published
findings and recommendations, we conducted a comprehensive online review of nursing literature published between 1980 and 2010 and included in the
Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, or the Health Reference Center Academic. We searched these databases
using the following keywords and phrases: “enteral
feeding,” “enteral nutrition,” “feeding tubes,” and
“verification of feeding tube placement.” We then
searched the reference lists of the articles we obtained
for additional sources. We considered all Englishlanguage, research-based articles pertaining to the
practice of placing enteral feeding tubes or assessing
enteral feeding tube placement in adult patients. We
applied no other inclusion criteria.
Our initial literature search yielded a total of 102
English-language articles, 44 of which were specifically related to enteral tube placement in adults. Of
these, 20 were research-based studies. We reviewed
those 20 studies for evidence that could shape practice. In addition, we reviewed 20 nursing textbooks
published between 2002 and 2010 for their current
practice recommendations on the subject.
In our convenience sample, hospital and skilled
nursing facility policies for assessing enteral feeding
tube placement varied considerably, with some simply referring nurses to a current nursing textbook (see
Table 1). The majority recommended the auscultatory method, with four using it as the sole means of
verifying tube placement, though its unreliability is
well established (see Table 2 15-31). Only 12 policies
specified a frequency at which tubes should be assessed for correct placement, and five hospitals that
admitted both adult and pediatric patients had no formal policy for assessing enteral feeding tube placement
in adult patients, one of which also had no formal policy for assessing enteral feeding tube placement in pediatric patients.
In our convenience sample, hospital
and skilled nursing facility policies for
assessing enteral feeding tube placement
varied considerably.
Auscultation. In 2005, the National Patient Safety
Agency of the United Kingdom issued a patient safety
alert in which they reported that, over a two-year period, 11 deaths and one case of serious harm resulted
from malpositioned small-bore nasogastric feeding
tubes.31 The alert clearly stated that “auscultation of
Table 2. Comparison of Feeding Tube Placement Methods
Assessment method
Advantages
Limitations
X-ray visualization of tube
Most reliable method currently available19, 20
Costly, undesirable patient exposure to repeated X-rays, not
always practical
pH testing of aspirate
Ease of use, reliable, can be used to distinguish between gastric and intestinal
tube placement17, 21- 23
Continuous gastric feeding and
medications for ulcers and reflux
raise gastric pH, possibly falsely
indicating that the tube is not in
the stomach24-26
Visual assessment of aspirate
Useful in distinguishing between gastric
and intestinal tube placement27
Color and consistency of aspirate
varies, of little value in differentiating between gastric and respiratory placement28
Visualization of external tube
length
Ease of use, may indicate if tube placement has shifted29, 30
Doesn’t indicate location of tube,
should never be used as sole
means of determining placement27
Auscultation of air insufflated
through the feeding tube for None19, 31
whooshing sounds
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Highly unreliable, whooshing
sound can be heard if tube is incorrectly placed in the lung15, 16, 18, 19, 31
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air insufflated through the feeding tube (‘whoosh
test’)” must not be used to assess placement of nasogastric feeding tubes and emphasized that use of
this method had, in several cases, wrongly suggested
that a tube was correctly placed, resulting in significant harm when feedings were initiated. Even so,
this method continues to be widely promulgated
and used.
In fact, several current nursing textbooks and
manuals continue to recommend the use of auscultation, either by itself,32 in combination with aspiration of gastric contents,33, 34 or as a preliminary
check prior to X-ray to avoid “ordering an X-ray
when the tube is clearly incorrectly placed”35—the
latter being a practice that can falsely suggest improper placement, resulting in unnecessary removal
of the tube. In our survey of policies and procedures, auscultation proved to be the most widely
practiced means of assessing enteral feeding tube
placement, with 17 of 28 New England hospitals
using this method.
pH testing. In 1989, investigators testing the effectiveness of measuring the pH of aspirated secretions to assess placement of a feeding tube found
that 80.8% of aspirates from enteral feeding tubes
placed in the stomach had pH paper readings of
were receiving one or the other of these medications.17
Likewise, commercially prepared feeding formulas, which typically have a pH close to 6.6, have an
alkalizing effect on stomach secretions.25 In a 1986
study of 366 gastric aspirates from 20 patients receiving nasoenteral feeding with Osmolite or Isocal
and no other gastric acid buffering, 96% of aspirates from the 10 patients receiving gastric feeding
and 43% from the 10 patients receiving intestinal
feeding had a gastric pH greater than 3.5.26 In a
2002 study of 80 patients receiving continuous tube
feeding, the mean pH of gastric aspirate as measured by pH test strips was 5.7.25
Because the pH level of gastric aspirate is often
elevated by either medication or enteral feeding formulas, pH testing isn’t always a reliable indicator
of gastric placement and may lead the examiner to
falsely suspect that the feeding tube is in the lung
or small intestines. To prevent alkalizing enteral
feeding formulas or medication from confounding pH testing, wait at least one hour after administering feedings or medications before assessing
pH, and flush the tube with 30 mL of air immediately before aspiration to clear it of other substances.43
Because the pH level of gastric aspirate is
often elevated by either medication or enteral feeding
formulas, pH testing isn't always a reliable indicator
of gastric placement.
1 to 4, while 87.4% of aspirates from tubes placed
in the intestines had pH paper readings of 6 to 9.21
Although X-rays revealed seven cases of pulmonary
placement, only one aspirate of the seven was tested;
it had a pH paper reading of 8. Numerous studies
support the use of aspiration and pH testing of aspirates to confirm proper placement of enteral feeding tubes.17, 22, 23, 36
At first glance, aspirating a small amount of tube
secretions and testing the pH of the aspirate seems
to be an easy and highly reliable method for confirming enteral feeding tube placement, and it is
recommended for this purpose in a number of current nursing texts.29, 37-42 There are, however, significant limitations to this method. Medications, such
as H2-receptor antagonists or proton pump inhibitors, which are frequently prescribed to prevent stress
ulcers and gastric reflux, can raise gastric pH as high
as 6.24 And in one study of 52 patients fed by nasogastric (50) or nasoenteric (2) tubes, 42% of patients
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Another limitation of pH testing may explain why
so few hospitals in our convenience survey included
it as part of their policy: at many hospitals, pH testing
is considered a point of care procedure, which, like
blood glucose testing, requires annual evaluation of
staff skill and competency. It is, therefore, more expensive and resource intensive to allow this practice
at the bedside.
Visualizing gastric aspirates. Aspiration of recognizable gastric content is often part of the process
used to confirm placement of an enteral feeding
tube. Gastric aspirates are described as being grassy
green or colorless, often with sediment. Intestinal
aspirates are often yellow or bile stained and either
clear or cloudy. Pleural aspirates are described as
watery and straw colored, while tracheobronchial
fluid is off-white or tan and often mixed with mucus.27 Unfortunately, the overlapping color and physical characteristics ascribed to the aspirates limit
this method significantly. In a study of 880 aspirates
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from nasally placed feeding tubes, observers found
it difficult to agree on the aspirates’ specific color
and clarity characteristics.28 Researchers concluded
that the visual characteristics of feeding tube aspirate can be helpful in distinguishing between gastric
and intestinal content but is of little value in differentiating between gastrointestinal and respiratory
placement.
Gastric contents are also aspirated to assess tolerance to the feeding and risk of aspiration. But in a
2005 randomized trial, risk of aspiration couldn’t be
determined from measuring residual volume.44 Of the
hospital policies we evaluated, it was unclear whether
gastric contents were aspirated as a means of checking tube placement or of monitoring gastric emptying.
Measuring feeding tube length. Current practice dictates that at the time of radiographic confirmation of tube site location, the tube should be
marked with indelible ink or adhesive tape where
it exits the nares.29, 30 On subsequent feedings, if the
nurse notes that more of the tube is exposed, the
position of the tip should be questioned. But this
method should never be the sole means of determining tube placement, because tubes that appear
to be securely taped can still migrate.27 Migration
is more likely with the commonly used small-bore
tubes.
OTHER METHODS OF ASSESSING PLACEMENT
Bilirubin aspirated from a feeding tube is useful
in determining placement because bilirubin is normally found in intestinal fluid and, in small amounts,
within the stomach if bile is refluxed from the duodenum. Bilirubin is rarely present in tracheobronchial or pleural fluid.22, 45 A colorimetric test for
detecting bilirubin is not yet available for use at
the bedside.23, 45
Another method that has been investigated for
use in mechanically ventilated patients is carbon dioxide measurement, using capnometry at the proximal end of the feeding tube. The color change that
indicates the presence of carbon dioxide is considered a sign of pulmonary tube placement.46 In some
studies, capnometry has proved remarkably reliable
for verifying enteral feeding tube placement in mechanically ventilated patients.15, 47 But in one study
of 69 mechanically ventilated patients, capnometry
incorrectly identified 16% of tubes as being in the
lung, suggesting that the technology needs to be refined.48
enteral feeding tubes. In 2009, however, the American
Association of Critical-Care Nurses (AACN) issued
a practice alert on the subject, containing a number
of evidence-based proposals.19
Before the tube is used to administer
feeding or medication, the AACN
recommends confirming placement
by X-ray.
During the blind insertion of any feeding tube,
the AACN recommends using several methods to
assess tube location. These include watching for signs
of respiratory distress, visually assessing aspirate, and
using pH testing, if available. Before the tube is used
to administer feeding or medication, the AACN recommends confirming placement by X-ray.19 Radiographic confirmation is particularly important when
small-bore tubes are used because they may produce
no symptoms when incorrectly placed and usually
require a stylet for insertion, which introduces the
risk of tissue perforation if the tube is not correctly
positioned.11
Once initial proper placement is confirmed by
X-ray, mark the tube’s exit site clearly with tape or
a permanent marker.19 Since all bedside methods of
assessing feeding tube placement have limited efficacy, the AACN suggests that nurses should assess
feeding tube placement at four-hour intervals, using
the following methods19:
• measure the external portion of the tube
• review routine chest and abdominal X-ray reports
• observe changes in the volume and appearance
of feeding tube aspirates
• test the pH of aspirates (if pH strips are available)
• obtain X-rays if tube placement is in doubt
Despite the plethora of evidence that’s been available since 1989, nurses continue to use the auscultatory method to assess enteral feeding tube placement,
whether out of habit or because of a lack of resources
and time. Until a completely reliable, simple, and
cost-effective means of assessing placement is available, nurses must be vigilant in using the best evidence to date. ▼
EVIDENCE-BASED PRACTICE
Despite decades of research on the subject, primarily by Metheny and colleagues, our literature review
uncovered no formal guidelines or practice recommendations from any professional association for
inserting and verifying placement of blindly inserted
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For 22 additional continuing nursing education articles on research topics, go to www.
nursingcenter.com/ce.
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Shellie Robin Simons is an assistant professor of nursing and
Lisa M. Abdallah is an associate professor of nursing, both
at the University of Massachusetts, Lowell. Contact author:
Shellie Robin Simons, shellie_simons@uml.edu. The authors
have disclosed no potential conflicts of interest, financial or
otherwise.
REFERENCES
1. Cerra FB, et al. Applied nutrition in ICU patients. A consensus statement of the American College of Chest Physicians.
Chest 1997;111(3):769-78.
2. Rassias AJ, et al. A prospective study of tracheopulmonary
complications associated with the placement of narrow-bore
enteral feeding tubes. Crit Care 1998;2(1):25-8.
3. Marderstein EL, et al. Patient safety: effect of institutional
protocols on adverse events related to feeding tube placement in the critically ill. J Am Coll Surg 2004;199(1):
39-47, 50.
4. Sorokin R, Gottlieb JE. Enhancing patient safety during
feeding-tube insertion: a review of more than 2,000 insertions. JPEN J Parenter Enteral Nutr 2006;30(5):440-5.
5. Metheny NA. Inadvertent intracranial nasogastric tube
placement. Am J Nurs 2002;102(8):25-7.
6. Phillips NM. Nasogastric tubes: an historical context. Medsurg Nurs 2006;15(2):84-8.
7. Grant MJ, Martin S. Delivery of enteral nutrition. AACN
Clin Issues 2000;11(4):507-16.
8. Harmer B, Henderson V. Textbook of the principles and
practice of nursing. 4th rev. ed. New York: Macmillan Company; 1939.
9. Sutton AL. Bedside nursing techniques in medicine and surgery. 2nd ed. Philadelphia: Saunders; 1969.
10. McDanal JT, et al. A complication of nasogastric intubation: pulmonary hemorrhage. Anesthesiology 1983;59(4):
356-8.
11. Metheny NA, Meert KL. Monitoring feeding tube placement. Nutr Clin Pract 2004;19(5):487-95.
12. Guiness R. How to use the new small-bore feeding tubes.
Nursing 1986;16(4):51-6.
13. Metheny N, et al. Effectiveness of the auscultatory method
in predicting feeding tube location. Nurs Res 1990;39(5):
262-7.
14. Neumann MJ, et al. Hold that x-ray: aspirate pH and auscultation prove enteral tube placement. J Clin Gastroenterol
1995;20(4):293-5.
15. Ackerman MH, Mick DJ. Technologic approaches to determining proper placement of enteral feeding tubes. AACN
Adv Crit Care 2006;17(3):246-9.
16. Metheny N, et al. Detection of inadvertent respiratory placement of small-bore feeding tubes: a report of 10 cases. Heart
Lung 1990;19(6):631-8.
17. Taylor SJ, Clemente R. Confirmation of nasogastric tube position by pH testing. J Hum Nutr Diet 2005;18(5):371-5.
18. Cannaby AM, et al. Nursing care of patients with nasogastric feeding tubes. Br J Nurs 2002;11(6):366-72.
19. American Society of Critical-Care Nurses. Verification of feeding tube placement (blindly inserted). Aliso Viejo, CA; 2009.
AACN practice alert; http://www.aacn.org/WD/Practice/Docs/
PracticeAlerts/Verification_of_Feeding_Tube_Placement_052005.pdf.
20. Metheny NA. Preventing respiratory complications of tube
feedings: evidence-based practice. Am J Crit Care 2006;
15(4):360-9.
21. Metheny N, et al. Effectiveness of pH measurements in
predicting feeding tube placement. Nurs Res 1989;38(5):
280-5.
22. Metheny NA, et al. pH and concentration of bilirubin in
feeding tube aspirates as predictors of tube placement. Nurs
Res 1999;48(4):189-97.
23. Metheny NA, Titler MG. Assessing placement of feeding
tubes. Am J Nurs 2001;101(5):36-45.
46
AJN ▼ February 2012
▼
Vol. 112, No. 2
24. Lanas A, et al. Effect of parenteral omeprazole and ranitidine on gastric pH and the outcome of bleeding peptic ulcer.
J Clin Gastroenterol 1995;21(2):103-6.
25. Metheny NA, Stewart BJ. Testing feeding tube placement
during continuous tube feedings. Appl Nurs Res 2002;
15(4):254-8.
26. Valentine RJ, et al. Does nasoenteral feeding afford adequate gastroduodenal stress prophylaxis? Crit Care Med
1986;14(7):599-601.
27. Sanko JS. Aspiration assessment and prevention in critically
ill enterally fed patients: evidence-based recommendations
for practice. Gastroenterol Nurs 2004;27(6):279-85.
28. Metheny N, et al. Visual characteristics of aspirates from
feeding tubes as a method for predicting tube location. Nurs
Res 1994;43(5):282-7.
29. Berman A, Snyder SJ. Kozier and Erb’s fundamentals of
nursing: concepts, process, and practice. 9th ed. Boston:
Pearson; 2012.
30. Metheny NA, et al. Indicators of tubesite during feedings.
J Neurosci Nurs 2005;37(6):320-5.
31. National Patient Safety Agency. Reducing the harm caused
by misplaced nasogastric feeding tubes in adults, children
and infants. London: National Health Service; 2011. http://
www.npsa.nhs.uk/corporate/news/reducing-the-harm-causedby-misplaced-nasogastric-feeding-tubes-in-adults-childrenand-infants/?locale=en.
32. Craven RF, Hirnle CJ, editors. Fundamentals of nursing: human health and function. 6th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams and Wilkins; 2009.
33. Nettina SM. Lippincott manual of nursing practice. 9th ed.
Philadelphia: Wolters Kluwer/Lippincott Williams and
Wilkins; 2010.
34. Smith SF, et al. Clinical nursing skills: basic to advanced
skills. 6th ed. Upper Saddle River, NJ: Pearson Prentice Hall;
2004.
35. Ellis JR, Bentz PM. Modules for basic nursing skills. 7th ed.
Philadelphia: Lippincott Williams and Wilkins; 2007.
36. Metheny NA, et al. Detection of improperly positioned feeding tubes. J Healthc Risk Manag 1998;18(3):37-48.
37. Altman GB, editor. Fundamental and advanced nursing
skills. 3rd ed. Clifton Park, NY: Delmar Cengage Learning;
2010.
38. Harkreader HC, et al. Fundamentals of nursing: caring and
clinical judgement. 3rd ed. St. Louis: Elsevier Saunders;
2007.
39. Lynn PB. Taylor’s clinical nursing skills: a nursing process
approach. 2nd ed. Philadelphia: Wolters Kluwer/Lippincott
Williams and Wilkins; 2008.
40. Perry AG, Potter PA, editors. Clinical nursing skills and
techniques. 7th ed. St. Louis: Mosby/Elsevier; 2010.
41. Smeltzer SC, et al., editors. Brunner and Suddarth’s textbook of medical-surgical nursing. 12th ed. Philadelphia:
Wolters Kluwer/Lippincott Williams and Wilkins; 2010.
42. Taylor C, et al. Fundamentals of nursing: the art and science of nursing care. 6th ed. Philadelphia: Wolters Kluwer/
Lippincott Williams and Wilkins; 2008.
43. Metheny N, et al. Effectiveness of pH measurements in predicting feeding tube placement: an update. Nurs Res 1993;
42(6):324-31.
44. McClave SA, et al. Poor validity of residual volumes as a
marker for risk of aspiration in critically ill patients. Crit
Care Med 2005;33(2):324-30.
45. Metheny NA, et al. Development of a reliable and valid bedside test for bilirubin and its utility for improving prediction
of feeding tube location. Nurs Res 2000;49(6):302-9.
46. Bourgault AM, Halm MA. Feeding tube placement in adults:
safe verification method for blindly inserted tubes. Am J Crit
Care 2009;18(1):73-6.
47. Araujo-Preza CE, et al. Use of capnometry to verify feeding
tube placement. Crit Care Med 2002;30(10):2255-9.
48. Elpern EH, et al. Capnometry and air insufflation for assessing initial placement of gastric tubes. Am J Crit Care 2007;
16(6):544-9.
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