Annals of Emergency Medicine
Volume 44, Issue 2 , Pages 138-141, August 2004

Nasogastric tubes: hard to swallow☆☆☆

  • E. John Gallagher, MD

      Affiliations

    • Corresponding Author InformationAddress for correspondence: E. John Gallagher, MD, Department of Emergency Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, 111 East 210th Street, Bronx, NY 10467; 718-920-7459

From the Department of Emergency Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY USA

See related article, p. 131.

Article Outline

 

Although patients and practitioners agree that nasogastric tube insertion is the most painful procedure commonly performed in the emergency department (ED), roughly 65% to 90% of emergency physicians do not use any form of anesthesia to reduce this discomfort.1., 2. This practice has persisted for many years in the face of an accumulating body of evidence indicating that virtually any form of topical anesthesia, applied as jelly, atomized spray, or nebulized aerosol to the nose, pharynx, or both, decreases the discomfort of nasogastric tube passage.2., 3., 4., 5., 6.

The article by Cullen et al7 in this month's issue of Annals is consistent with earlier work on healthy volunteers showing that nebulized lidocaine4 delivered to the nose and pharynx by face mask is associated with a clinically and statistically significant reduction in the discomfort of nasogastric tube insertion.7 With the publication of this study, there are now at least 6 randomized clinical trials in the English-language literature supporting the use of topical anesthesia to decrease the discomfort of nasogastric tube passage.2., 3., 4., 5., 6., 7. No trials with contrary results could be found.

For readers interested mainly in how current evidence on this topic may affect their clinical practice, skip immediately to the end of this editorial and scan the 4 items listed under the section titled “Clinical Bottom Line” (this will take about 5 minutes). For those who wish to know a little (but not a lot) more about the evidence base supporting these bottom-line recommendations, refer to the Table (about 10 minutes). For clinical investigators interested in acute pain management, a list of considerations and questions pertinent to future research immediately precedes the section “Clinical Bottom Line” (about 15 minutes). Finally, for those readers who would like to examine the data underlying this evidence in detail, a summary of each clinical trial is presented below in chronological order (this will take about 30 to 45 minutes of your time).

Table. Summary of evidence from clinical trials investigating nasogastric anesthesia.
TrialConclusion
Nott and Hughes3Lidocaine nasal spray 4% reduces nasogastric discomfort more than placebo
Singer and Konia2Intranasal lidocaine jelly 2% plus pharyngeal Cetacaine spray (tetracaine 2% plus benzocaine 14%) plus phenylephrine nasal spray 0.5% reduces nasogastric discomfort more than placebo
Spektor et al4Nebulized nasal and pharyngeal lidocaine 4% reduces nasogastric discomfort and incidence of complications compared with nasal and pharyngeal lidocaine spray 10% among all subjects pretreated with lidocaine jelly 2% plus phenylephrine nasal spray 0.5%
Wolfe et al5Nasal and pharyngeal lidocaine spray 4% added to lidocaine jelly 2% reduces nasogastric discomfort more than lidocaine jelly 2% alone
Ducharme and Matheson6Trend favoring lidocaine jelly 2% over cocaine 4% and lidocaine nasal spray 4% for reduction of nasogastric discomfort not strong enough to draw firm conclusions
Cullen et al7Nebulized nasal and pharyngeal lidocaine 10% reduces nasogastric discomfort more than placebo, but may increase epistaxis

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1. The evidence base 

1.1. Randomized clinical trial #1 

In 1995, Nott and Hughes3 randomly allocated 63 adult patients requiring nasogastric tubes to 3 equal groups of 21 patients. The experimental group received 0.5 to 1.0 mL of lidocaine 4% (20 to 40 mg of lidocaine) applied as a spray by means of atomizer to the nose only. The placebo group received normal saline solution nasal spray. The control group received no spray. Vasoconstrictors were not used. Although blinding was attempted, it was probably unsuccessful. Practitioners of varying skill and experience (71% physicians, 29% nurses) inserted nasogastric tubes (size not reported) using plain gel lubricant. Ninety percent of the experimental group reported none to moderate discomfort versus 60% of the combined placebo and control groups, for a difference of 30% (95% confidence interval [CI] 12% to 50%). No difference between the groups in the difficulty of tube insertion was found, and no complications were reported.

Conclusion: Lidocaine nasal spray decreases the discomfort of nasogastric tube insertion. This difference appears to be both clinically and statistically significant.3

1.2. Randomized clinical trial #2 

In 1999, Singer and Konia2 randomly allocated 40 adult ED patients requiring nasogastric tubes into 2 equal groups of 20 patients. The experimental group received a vasoconstrictor (phenylephrine 0.5% nasal spray) plus 2 topical anesthetics: (1) 5 mL of intranasal lidocaine jelly 2% (100 mg of lidocaine) and (2) Cetacaine spray (combination of tetracaine 2% and benzocaine 14%) applied to the pharynx. The control group received no topical anesthetics or vasoconstrictors. Physicians, whose technique was standardized before beginning the study, inserted 16F nasogastric tubes using plain gel lubricant. Blinding was deemed impractical, and no placebo spray was used. The primary endpoint of mean difference in overall pain score as measured on a visual analog scale was 29 mm (95% CI 12 to 45 mm), favoring the group that received topical anesthesia. No between-group differences in the difficulty of tube insertion or other complications were found. Epistaxis was not reported in either group.

Conclusion: Lidocaine intranasal jelly, combined with Cetacaine (tetracaine plus benzocaine) pharyngeal spray and a nasal vasoconstrictor, decreases the discomfort of nasogastric tube insertion. This difference appears to be both clinically8., 9. and statistically significant.2

1.3. Randomized clinical trial #3 

In 2000, Spektor et al4 reported findings from a randomized crossover study in which 10 healthy adult volunteers had nasogastric tubes inserted after receiving each of the following regimens on 3 separate occasions at least 24 hours apart: (1) 2.5 mL of nebulized lidocaine 4% to the nose and pharynx (100 mg of lidocaine) plus normal saline solution nasal spray plus normal saline solution pharyngeal spray; (2) nasal lidocaine 10% spray plus pharyngeal lidocaine 10% spray (100 mg of lidocaine total) plus nebulized normal saline solution; and (3) normal saline solution nasal spray plus normal saline solution pharyngeal spray plus normal saline solution via nebulizer.4 On all occasions, subjects received 5 mL of intranasal lidocaine 2% jelly (100 mg of lidocaine) plus 0.5% phenylephrine nasal spray. All nasogastric tubes were 16F and were passed by a single operator. The primary endpoint of mean within-subject difference in visual analog scale pain scores was 15 mm (95% CI 8 to 22 mm), favoring nebulized lidocaine over sprayed lidocaine. Complications (defined as epistaxis, gagging, coughing, choking, or vomiting) occurred less frequently in the nebulized lidocaine arm than in the lidocaine spray arm (difference in incidence of complications 43% [95% CI 22% to 65%]).

Conclusion: Among healthy volunteers, all of whom received intranasal lidocaine jelly and a nasal vasoconstrictor, those randomized to nebulized lidocaine delivered to the nose and pharynx had less discomfort and fewer complications from nasogastric tube insertion than those randomized to nasal and pharyngeal lidocaine spray. The difference in discomfort and complications appears to be both clinically8., 9. and statistically significant.4

1.4. Randomized clinical trial #4 

In 2000, Wolfe et al5 randomly allocated 40 adult ED patients requiring nasogastric tubes into 2 equal groups of 20 patients. The experimental group received 5 mL of intranasal lidocaine 2% jelly plus 1.5 mL of nasal lidocaine 4% spray plus 3 mL of pharyngeal lidocaine 4% spray, for a total dose of 280 mg of lidocaine. The control group received 5 mL of intranasal lidocaine 2% jelly plus normal saline solution nasal and pharyngeal spray, for a total dose of 100 mg of lidocaine. Lidocaine spray was delivered by means of a disposable mucosal atomization device. Lidocaine jelly was used in both groups to promote blinding. No vasoconstrictors were used. Experienced ED nurses inserted 16F nasogastric tubes. The primary endpoint of mean difference in overall pain score as measured on a visual analog scale was 27 mm (95% CI 15 to 39 mm), favoring the group receiving topical nasal and pharyngeal lidocaine spray. There were no inadvertent tracheal intubations. Other complications were not reported.

Conclusion: Addition of nasal and pharyngeal lidocaine spray to intranasal lidocaine jelly decreases the pain of nasogastric tube insertion compared with lidocaine jelly alone. This difference appears to be both clinically8., 9. and statistically significant.5

1.5. Randomized clinical trial #5 

In 2003, Ducharme and Matheson6 reported findings from a randomized crossover study in which 30 healthy adult volunteers had 3 nasogastric tubes inserted after receiving each of the following 3 regimens an hour apart: (1) 5 mL of intranasal lidocaine 2% jelly (100 mg of lidocaine) plus normal saline solution nasal spray; (2) 1.5 mL of atomized nasal lidocaine 4% spray (60 mg of lidocaine) plus 5 mL of intranasal placebo gel; and (3) 1.5 mL of atomized nasal cocaine 4% spray (60 mg of cocaine) plus 5 mL of intranasal placebo gel. In all 3 arms of the study, participants received 2 sprays of topical lidocaine to the pharynx to preserve blinding. All sprays were delivered by means of a disposable mucosal atomization device. No vasoconstrictors were used. All nasogastric tubes were 16F and were passed by a research assistant. The primary endpoint of mean within-subject difference in overall discomfort as measured on a visual analog pain scale found a trend favoring lidocaine gel.

Conclusion: In subjects receiving pharyngeal lidocaine spray, there was a trend favoring intranasal lidocaine gel over atomized cocaine nasal spray, and to a lesser extent, over atomized lidocaine nasal spray. However, this trend was not clinically or statistically of sufficient magnitude to support any firm conclusions.6., 8., 9.

1.6. Randomized clinical trial #6 

In this month's issue of Annals, Cullen et al7 randomized 50 adult ED patients requiring nasogastric tubes into 2 unequal groups. The experimental group (N=29) received 4 mL of lidocaine 10% (400 mg of lidocaine) delivered to the nose and pharynx by means of face mask nebulizer. The placebo group (N=21) received nebulized normal saline solution. Vasoconstrictors were not used. ED nurses passed 18F nasogastric tubes using plain gel lubricant. The primary endpoint of mean between-group difference in overall discomfort as measured on a visual analog scale was 22 mm (95% CI 5 to 38 mm), favoring the group that received nebulized lidocaine. There was no detectable difference in difficulty of insertion. However, epistaxis occurred more frequently in the lidocaine group (17% versus 0%, 95% CI for difference of 17% [4% to 31%]).

Conclusion: Nebulized lidocaine delivered to the nose and pharynx by means of nebulizer decreases the discomfort of nasogastric tube insertion. This difference appears to be both clinically and statistically significant.8., 9. Whether the increased incidence of epistaxis in the experimental group is caused by injury of insensate nasal mucosa, and if so, whether this may be reduced with vasoconstrictors remain unanswered.7

An additional interesting question raised by Cullen et al7 is whether lidocaine delivered by nebulizer is superior to sprayed lidocaine delivered by atomizer. The main difference between the 2 methods of delivery is that a nebulizer provides continuous delivery of medication and has baffles, which are designed to remove large droplets from the outgoing mist.10

Recently, concerns have surfaced about cross-contamination of patients by means of multi-use atomizers,11., 12. leading to a recommendation that single-use disposable atomizers be used.13 Indeed, 2 of the clinical trials discussed in this editorial used single-use, disposable atomization devices to deliver anesthetic sprays.5., 6. Until this question is resolved, it seems wise to avoid multi-use atomizers and use either disposable atomizers or (disposable) nebulizers. On the basis of a single small study, nebulizers may have a slight edge over atomized spray delivery.4

The theoretical concern that nasogastric anesthesia might place patients at increased risk of inadvertent tracheal intubation due to depression of protective airway reflexes has thus far not been substantiated. Among studies that examined this complication, either no difference was found between groups2., 5., 7. or there were fewer tracheal placements of nasogastric tubes among subjects receiving pharyngeal anesthesia than among those given placebo (difference of 22% [95% CI 4% to 40%]).4 This finding is consistent with the observation that coughing is associated with nasogastric tube misplacement.3 Although coughing may simply be a physiologic response to a nasogastric tube mistakenly passed into the larynx, it is also possible that it may sometimes be the cause rather than the effect of inadvertent tracheal intubation. This is at least plausible because the initial inspiratory phase of a cough entails a deep inspiration through a widely opened glottis, thus providing an opportunity for a nasogastric tube to slip into the trachea rather than the esophagus. The probability of tube misplacement into the airway might therefore be diminished if coughing is suppressed by application of local anesthesia, thus maintaining a closed glottis.14., 15.

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2. Some considerations and questions pertinent to future research 

1.Although institutional review boards will make their decisions on the basis of the nature of the clinical question posed to them by individual investigators, in many instances, it may no longer be ethical to randomize patients to a placebo arm when conducting clinical trials of nasogastric anesthesia.

2.What is the optimal vehicle for minimization of nasogastric tube discomfort and complications: lidocaine jelly, atomized spray, or aerosol nebulizer? On the basis of prior evidence,2., 4., 5., 6. this question might be better targeted at identification of the optimal anesthetic combination (eg, atomized nasal and pharyngeal spray plus intranasal lidocaine jelly versus nebulized aerosol via face mask plus intranasal lidocaine jelly).

3.What is the optimal concentration (4% versus 10%) of lidocaine, delivered either by atomized spray or face mask nebulizer, for minimization of discomfort and complications?

4.Is reduction of the “cough reflex” through application of topical anesthesia associated with an increase or decrease in inadvertent tracheal placement of nasogastric tubes?

5.What is the incidence of bronchospasm associated with nebulized lidocaine among patients without a prior history of reactive airway disease?

6.Is there an anesthetic threshold beyond which complications such as epistaxis and tube misplacement begin to increase as a result of complete loss of mucosal sensation?

7.Do nasal vasoconstrictors reduce the incidence of epistaxis when used with topical anesthetics?

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3. Clinical bottom line 

As a cursory examination of the summary findings of the above clinical trials will confirm, the published data on nasogastric anesthesia are too heterogeneous for a formal meta-analysis. Nevertheless, based on the weight of current evidence and the consistent direction in which all of it appears to be pointing, it seems reasonable to propose a bottom-line practice recommendation. As is true of all such recommendations, this one will undoubtedly be modified over time as further evidence accumulates and understanding evolves.

1.On the basis of all currently available evidence, it no longer appears justifiable to pass a nasogastric tube in a nonemergency patient without providing some form of topical anesthesia.2., 3., 4., 5., 6., 7.

2.Lidocaine, which can be administered as intranasal jelly,2., 4., 5., 6. nebulized aerosol,4., 7. or atomized spray,2., 3., 4., 5., 6. appears to be the agent of choice.

3.The optimal route of delivery, concentration, and therapeutic combinations have not been established. However, the 2 main evidence-based options at present appear to be either: (a) preservative-free lidocaine, 10%, 4 mL, nebulized by face mask (400 mg of lidocaine total),7 not to be used in patients with asthma16 or (b) preservative-free lidocaine spray, 4%, delivered by single-dose atomizer to the nose (1.5 mL) and pharynx (3 mL), followed by intranasal lidocaine jelly, 2%, 5 mL, sniffed and swallowed (280 mg of lidocaine total).5

4.Although the role of vasoconstrictors in reducing the incidence of epistaxis is unclear,7 2 sprays of phenylephrine, 0.5%, in each nostril seem unlikely to cause any harm, and pending further evidence, may provide prophylaxis against nosebleeds.

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References 

  1. Singer AJ, Richman PB, Kowalska A, et al.  Comparison of patient and practitioner assessments of pain from commonly performed emergency department procedures. Ann Emerg Med. 1999;33:652–658
  2. Singer AJ, Konia N. Comparison of topical anesthetics and vasoconstrictors vs lubricants prior to nasogastric intubation: a randomized, controlled trial. Acad Emerg Med. 1999;6:184–190
  3. Nott MR, Hughes JH. Topical anesthesia for the insertion of nasogastric tubes. Eur J Anasethesiol. 1995;12:287–290
  4. Spektor M, Kaplan J, Kelley J, et al.  Nebulized or sprayed lidocaine as anesthesia for nasogastric intubations. Acad Emerg Med. 2000;7:406–407
  5. Wolfe TR, Fosnocht DE, Linscott MS. Atomized lidocaine as topical anesthesia for nasogastric tube placement: a randomized, double-blind, placebo-controlled trial. Ann Emerg Med. 2000;35:421–425
  6. Ducharme J, Matheson K. What is the best topical anesthetic for nasogastric insertion? A comparison of lidocaine gel, lidocaine spray, and atomized lidocaine. J Emerg Nurs. 2003;29:427–430
  7. Cullen L, Taylor D, Taylor S, et al.  Nebulized lidocaine decreases the discomfort of nasogastric tube insertion: a randomized, double-blind trial. Ann Emerg Med. 2004;44:131–137
  8. Todd KH, Funk KG, Funk JP, et al.  Clinical significance of reported changes in pain severity. Ann Emerg Med. 1996;27:485–489
  9. Gallagher EJ, Liebman M, Bijur PE. Prospective validation of clinically important changes in pain severity measured on a visual analog scale. Ann Emerg Med. 2001;38:633–638
  10. O'Callaghen C, Barry PW. The science of nebulized drug delivery. Thorax. 1997;52(Suppl 2):S31–S44
  11. Spraggs PD, Hanekom WH, Mochloulis G, et al.  The assessment of the risk of cross-infection with a multi-use nasal atomizer. J Hosp Infect. 1994;28:315–321
  12. Southwick KL, Hoffmann K, Ferree K, et al.  Cluster of tuberculosis cases in North Caroline: possible association with atomizer reuse. Am J Infect Control. 2001;29:1–6
  13. Croakley JF, Arthurs GJ, Wilsher TK. The need for and development of a single use disposable nasal spray. J Laryngol Otol. 1993;107:20–23
  14. Leith DE, Butler JP, Sneddon SL, et al.  Cough. In:  Cherniack NS,  Widdicombe JG editor. Handbook of Physiology (Section 3: Respiration. Vol 3: Mechanisms of Breathing (Part 1)). Baltimore, MD: American Physiological Society; 1986;p. 315–336
  15. Bianco S, Robuschi M. Mechanics of cough. In:  Braga PC,  Allegra L editor. Cough. New York, NY: Raven Press; 1989;p. 29–36
  16. Miller WC, Awe R. Effect of nebulized lidocaine on reactive airways. Am Rev Respir Dis. 1975;111:739–741

☆ The author reports this study did not receive any outside funding or support.

☆☆ Reprints not available from the author.

PII: S0196-0644(04)00417-2

doi:10.1016/j.annemergmed.2004.04.009

Annals of Emergency Medicine
Volume 44, Issue 2 , Pages 138-141, August 2004

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