Gum Elastic Bougie Resources

Should Paramedics Bougie on Down?

Pitt, K., Woollard, M.

Should paramedics bougie on down? Pre-hospital Immediate Care. 2000;4:68-70. Reproduced with the permission of BMJ Publishing Group. This is copyrighted and must not be reproduced without permission of the authors.

Authors Karen Pitt, Welsh Ambulance Services NHS Trust, Central and West Region, Welsh Ambulance Services NHS Trust Malcolm Woollard, Pre-hospital Emergency Research Unit, University of Wales College of Medicine / Welsh Ambulance Services NHS Trust Corresponding Author: Malcolm Woollard Pre-hospital Emergency Research Unit Lansdowne Hospital Sanatorium Road Cardiff CF1 8UL Tel: 02920 233651 ext. 2930 Fax: 02920 237930 Email: Malcolm.peru@ukgateway.net

Abstract

Objective
The objective of this literature search was to find evidence to support (or refute) the use of the gum elastic bougie type endotracheal tube introducer by paramedics.

Methods
An on-line literature search was made of the Cochrane Library, Medline and the World Wide Web. Information retrieved from the Web was utilised as a source of further references only. A hand search of the Annals of Emergency Medicine was also conducted. The key text words utilised were 'bougie,' 'elastic,' 'gum bougie' and 'Eschmann.' References from retrieved papers were also sought and reviewed where available. A critical appraisal was conducted of each paper to determine internal and external validity.

Results
Seven papers were ultimately considered. None addressed the use of the bougie by paramedics. One RCT showed a 30% difference in successful intubation rates in favour of the bougie, which was highly significant (p<0.001, 95% CI = 0.15 to 0.45). A second RCT also found a higher success rate with the bougie (p<0.02). A third RCT demonstrated that maintaining laryngoscopy and rotating the bevel of the ETT to face posteriorly resulted in a 52% improvement in first time success rates. A fourth RCT showed the median intubation time was quicker for direct visualisation (18 versus 28 seconds, p<0.001) although three patients could only be intubated using a bougie. A further study reported the efficacy of feeling for clicks and bougie 'hold up' as a means of verifying tracheal placement. No study reported any serious sequelae to bougie use or increased incidence of minor complications.

Conclusions
The bougie appears to increase the first time intubation success rate. It does not seem to result in a significant reported incidence of minor or serious complications. As it's use by paramedics is unproven its introduction should be accompanied by a detailed outcome audit.

Introduction
But for the gum elastic bougie, many difficult endotracheal intubations could not be accomplished without the use of more invasive techniques. This re-usable instrument, also known as the Eschmann tracheal tube introducer (Portex Limited, Hythe, UK), is a 60cm long, 15 French Gauge flexible device with a J (coudé) angle at its distal tip. During use a curve is also formed towards its distal end. A disposable equivalent is also available (Portex, op cit).

When used to assist in the intubation of a patient with an anterior glottis, the bougie is advanced anterior to the arytenoid cartilages and in the mid-line, under direct laryngoscopy. The tip is advanced into the trachea whilst the intubator feels for clicks as it passes over the tracheal rings. The endotracheal tube (ETT) is then rail-roaded over the bougie, which is held firmly in place. Once the ETT is in situ the laryngoscope and bougie are withdrawn, and correct placement in the trachea is confirmed using standard techniques. The bougie is considerably more flexible than a stylet inserted in an endotracheal tube and it has been argued that it is therefore relatively atraumatic in use.[1]

The gum elastic bougie was introduced into anaesthetic practice in 1949 by Sir Robert Macintosh.[2] Since this time it has become an important adjunct in the management of difficult intubation by anaesthetists. One survey conducted in 1988 showed that a bougie was used as the first strategy in managing ninety percent of cases of difficult intubation.[3] According to Latto, the preference of anaesthetists has changed in favour of the bougie at the cost of the malleable stylet.[3] Gataure hypothesised that this was as a result of a growing realisation by anaesthetists that the bougie was superior to the stylet under such circumstances.[1]

This paper seeks to address the question of whether the bougie is an appropriate device for use by paramedics in the pre-hospital milieu.

Methods
A literature search was undertaken using the facilities of the University of Wales College of Medicine and the Post-Graduate Medical Centre of the West Wales General Hospital. An on-line search was made of the Cochrane Library, Medline and the World Wide Web. Information retrieved from the Web was utilised as a source of further references only. A hand search of the Annals of Emergency Medicine was also conducted. The key text words utilised were 'bougie,' 'elastic,' 'gum bougie' and 'Eschmann.' References from retrieved papers were also sought and reviewed where available. A critical appraisal was conducted of each paper to determine internal and external validity.

Results
Seven papers from peer reviewed medical journals were ultimately considered. The papers included four randomised controlled trials, [1], [4], [5], [6] one intervention study, [7] one case report [8] and one discussion paper. [9]

No papers, with the exception of the case report, addressed the use of the gum-elastic bougie by paramedics or in the pre-hospital environment.

Gataure , et al. [1] in a randomised controlled trial of 100 patients, compared the efficacy of the bougie versus the stylet in patients with simulated difficult intubation. This trial showed a 30% difference in success rates in favour of the bougie which was highly significant (p<0.001, 95% CI = 0.15 to 0.45).

Nolan et al. [4] compared the use of bougies against direct visual intubation in patients held in manual in-line stabilisation of the cervical spine with cricoid pressure applied. Of 157 patients the view of the larynx was reduced in 45% and nothing beyond the epiglottis was visible in 22%. Seventy-nine patients were randomised to direct visual intubation and seventy-eight to bougie-assisted intubation. Five patients in the direct visual group could not be intubated, but all patients (including the failures from the first group) were successfully intubated using the bougie (p<0.02). The trial also found that whilst the mean intubation time was quicker in the visualisation group this included eleven patients where the procedure took longer than forty five seconds. Conversely, none of the procedures in the bougie group took longer than forty-five seconds (p<0.001).

Dogra et al [5] examined the efficacy of different intubation techniques (all using a bougie) in 100 patients. These included withdrawing the laryngoscope prior to passing the ETT over the pre-positioned bougie, leaving the laryngoscope in situ, and rotation of the ETT so that the bevel faced posteriorly. Patients were randomised in equal numbers to passage of the ETT with a laryngoscope in situ or intubation with the laryngoscope withdrawn. There was a 74% first time success rate in the former group compared with 22% in the latter (p<0.000001). When the laryngoscope was left in situ there was a 52% improvement in first time success rates if the ETT was rotated so that its bevel faced posteriorly during its passage over the bougie.

Nolan et al [6] examined 149 patients who were randomised to either a simulated 'epiglottis-only' view with intubation assisted by use of a bougie and tube rotation, or direct visual laryngoscopy without simulation of an epiglottis-only view. Whilst the median intubation time was quicker for the laryngoscopy group (18 versus 28 seconds, p<0.001) three patients could not be intubated in this sample. These individuals were subsequently intubated with the assistance of a gum-elastic bougie. This study also compared the incidence of sore throat in each group. No statistically significant difference was noted.

Kidd et al. [7] examined 100 patients with real or simulated difficult intubations to determine the reliability of the presence of tracheal ring 'clicks' and bougie 'hold-up' (which occurs when the tip reaches the small bronchi) as a means of confirming correct placement of a bougie. Actual placement was verified under direct vision with a laryngoscope. In 78 patients the bougie was laryngoscopically confirmed as being positioned in the trachea. Clicks were felt in 89.7% of this group, and hold-up of the bougie occurred in 100%. Oesophageal placement occurred in twenty-two patients. Neither clicks nor hold-up occurred in any of these. The authors cautioned against the use of excessive force when utilising this procedure due to the theoretical risk of causing damage to a bronchus.

Nocera's case study [8] describes the use of a bougie in the pre-hospital environment to facilitate intubation in a patient with head injuries following rapid sequence induction. The patient was trapped and this resulted in a very limited view of the epiglottis being obtained. The author of this paper states that since "…the view of the larynx was rotated in two planes, the use of a stylet-mounted tube would have totally obscured the available view of the larynx." In their paper discussing difficult intubation in obstetric patients Cormack et al. [9] recommend the use of the Macintosh technique, which includes insertion of a gum elastic bougie.

Discussion
When called upon to intubate, paramedics are often working under less than ideal conditions. Patients may be poorly positioned, in hostile weather conditions, and without the availability of adequate lighting. Further, they may not be fully relaxed as no anaesthetic will have been given. Intubation is widely accepted as the gold standard for airway management. [10] Consequently, paramedics must be equipped and trained to maximise their success rate in utilising this technique under all such circumstances.

The internal validity of the studies described has been assessed using critical appraisal techniques, [11] including consideration of the study design and statistical methodology and results. However, our review highlights a lack of external validity since we were unable to find any trials involving paramedics or the pre-hospital environment. This could, in part, be due to the fact that the bulk of pre-hospital research is conducted in the USA where the gum bougie is, by tradition, rarely used. [12]But, as Cochrane is often quoted as stating, 'absence of evidence of effect is not evidence of absence of effect' [13] and it is not, therefore, unreasonable to assume that some patients may benefit from paramedics having access to this technique.

In almost all of the above studies, unassisted direct laryngoscopy was insufficient to allow successful intubation in a small number of patients, even when practised by experienced anaesthetists. Simple options for assisting intubation when the view is limited include the stylet and the bougie. Gataure et al. [1] unequivocally demonstrate the superior results obtained with the latter device.

Use of correct technique is vital in facilitating first time success in placing the ETT in the trachea. Nolan et al. [6] conclude that leaving the laryngoscope in situ and rotating the endotracheal tube so that the bevel faces the posterior wall of the pharynx significantly enhance success rates. The value of training operators to feel for clicks and bougie hold-up has been demonstrated by Kidd et al. [7] It can be safely advised that failure to detect clicks or hold-up is indicative of oesophageal placement of the bougie. However, we feel it prudent to suggest that the presence of clicks or hold-up should not be taken as a definitive indication of subsequent correct tracheal positioning of the ETT. Additional measures to confirm correct ETT placement on completion of the procedure are vital. These may include auscultation of the lung fields and epigastrium, and use of an oesophageal bulb device or quantitative end-tidal CO2 detector.[14]

Importantly, no serious adverse events related to the use of a bougie were reported in any of the papers reviewed. Whilst sore throat was documented to occur by Nolan et al. [6] the incidence was the same regardless of whether a bougie was used. However, a theoretical risk exists of causing damage to the structures of the airway as a result of the use of excessive force.[7]

Conclusion and Recommendations
This review has demonstrated the value of the gum elastic bougie in assisting difficult intubation. The risk of serious adverse events appears to be slight. Given the current climate of evidence-based medicine and best clinical practice, we feel it appropriate to recommend that paramedics be trained and authorised to employ this procedure, using the techniques discussed elsewhere in this paper. However, since no research has been conducted in the pre-hospital arena, it will be vital to conduct a sound outcome audit to confirm patient benefits. Training programmes must address the factors which increase the risk of damage to the structures of the airway when using a bougie, and emphasise the importance of using a range of strategies to confirm correct ETT position.

Acknowledgements
The authors gratefully acknowledge the assistance provided by two peer reviewers in improving an earlier draft of this paper.

Contributors
Karen Pitt conceived the idea of conducting this review and undertook the literature search. Critical appraisal of retrieved literature, writing and editing of this paper were undertaken jointly by Karen Pitt and Malcolm Woollard.

References
[1] Gataure, P.S., Vaughan, R.S., Latto, I.P. Simulated difficult intubation: comparison of the gum elastic bougie and the stylet. Anaesthesia, 1996;51:935-938.
[2] Macintosh, R.R. An aid to oral intubation. British Medical Journal, 1949;1:28
[3] Latto, I.P., Rosen, M. Difficulties in tracheal intubation. Eastbourne: Balliere Tindall / W.B. Saunders, 1985:103.
[4] Nolan, J.P., Wilson, M.E. Orotracheal intubation in patients with potential cervical spine injuries. Anaesthesia, 1993;48:630-633.
[5] Dogra, S., Falconer, R., Latto, I.P. Successful difficult intubation: tracheal tube placement over a gum elastic bougie. Anaesthesia, 1990;45:776-780.
[6] Nolan, J.P., Wilson, M.E. An evaluation of the gum elastic bougie: intubation times and incidence of sore throat. Anaesthesia, 1992;47:878-881.
[7] Kidd, J.F., Dyson, A., Latto, I.P. Successful difficult intubation: use of the gum elastic bougie. Anaesthesia, 1988;43:437-438.
[8] Nocera, A. A flexible solution for emergency intubation difficulties. Annals of Emergency Medicine, 1996;27(5):665-667.
[9] Cormack, R.S., Lehane, J. Difficult tracheal intubation in obstetrics. Anaesthesia, 1984;39:1105-1111.
[10] Guss, D.A., Posluszny, M. Paramedic orotracheal intubation: a feasibility study. Am J Emerg Med, 1984;2(5):399-401.
[11] Greenhalagh, T. How to read a paper: the basics of evidence based medicine. London: BMJ Publishing Group, 1997.
[12] McCarroll, S.M., Lamont, B.J., Buckland, M.R., et al. The gum elastic bougie: old but still useful. Anesthesiology, 1988;68:643-644.
[13] Cochrane, A.L. Effectiveness and Efficiency: Random Reflections on Health Services. Abingdon: the Nuffield Provincial Hospital Trust, 1971.
[14] Zaleski, L; Abello, D., Gold, M.I. The esophageal detector device. Does it work? Anesthesiology, 1993;79(2):244-7.

Difficult intubation protocol: use of the endotracheal tube introducer (gum-elastic bougie)

Woollard, M., Pitt, K. Internal document. Welsh Ambulance Services NHS Trust.

Description
The Eschmann tracheal tube introducer (formerly known as the gum elastic bougie) is a 60cm long, 15 French Gauge flexible device with a J angle at its distal tip. During use a curve is also formed towards its distal end. The device should be clinically clean prior to use but does not need to be sterile. Both re-usable and disposable versions are available.

Rationale for use
The tracheal tube introducer is used to facilitate difficult intubation. It should not be confused with the more rigid stylet, which is inserted into the ET tube and used to alter its shape prior to intubation. Unlike the stylet a bougie is inserted independently of the ET tube and is used as a guide. Since the bougie is considerably softer, more malleable, and blunter than a stylet this technique is considered to be a relatively atraumatic procedure.

Indications

• Difficult intubation with a restricted view of the glottic opening. This may occur due to:
• Short, thick (bull) neck;
• Pregnancy;
• Laryngeal oedema (anaphylaxis, burns);
• Normal anatomical variation;
• Supra-glottic neoplasms (tumours above the glottic opening);
• Inability to position patient appropriately (e.g. entrapment, confined space).

Contra-indications

• Paediatric patients under the age of 14.

Method
Where a difficult intubation is anticipated, or a poor view of the glottic opening has been confirmed on laryngoscopy:

1) Hyperventilate the patient with 100% oxygen for at least one minute prior to each intubation attempt. Note, however, that this step should be omitted when ventilation (demonstrated by rise and fall of the chest) proves impossible.
2) Have suction running with the tip placed under the patient's shoulder. Use wide bore tubing, not an endotracheal catheter.
3) Prepare the ET tube for a crash intubation: cut to length, and with a syringe, catheter mount, and tube-tie pre-attached.
4) Prepare a second ET tube one size smaller than normal, as above. This may be required in the event of laryngeal oedema.
5) Consider using a number four laryngoscope blade.
6) Use at least one pillow or equivalent to place the patient's head in the 'sniffing the morning air' position.
7) Insertion of the laryngoscope may prove very difficult in pregnant or obese patients. This may be overcome by removing the blade from the handle, inserting it, and then re-attaching the handle with the blade in the mouth.
8) Each intubation attempt must take no more than thirty seconds from the point at which the last inflation is given. After this time has expired, if not successful, abandon the procedure and hyperventilate again for one minute with 100% oxygen prior to further attempts. If ventilation is not possible consider seeking more expert help.
9) Prepare the endotracheal tube introducer for use:

• Curve the bougie and ensure the distal tip is formed into a J (coudé) shape;
• Perform a laryngoscopy, obtaining the best possible view of the glottic opening. You should always be able to view the tip of the epiglottis and, ideally, the arytenoid cartilages;
• Advance the bougie, continually observing its distal tip, with the concavity facing anteriorly;
• Visualise the tip of the bougie passing posteriorly to the epiglottis and (where possible) anterior to the arytenoid cartilages;
• Once the tip of the bougie has passed the epiglottis, continue to advance it in the mid-line so that it passes behind the epiglottis but in an anterior direction (figure 1);
• As the tip of the bougie enters the glottic opening you will either feel 'clicks' as it passes over the tracheal rings or the tip will arrest against the wall of the airways ('hold-up'). This suggests correct insertion, although cannot be relied upon to indicate correct positioning with 100% accuracy. HOWEVER, FAILURE TO ELICIT CLICKS OR HOLD-UP IS INDICATIVE OF OESOPHAGEAL PLACEMENT. If hold-up is felt, the bougie should then be withdrawn approximately 5cm to avoid the ET tube impacting against the carina.
• Hold the bougie firmly in place AND MAINTAIN LARYNGOSCOPY.
  • Instruct your colleague to pass the endotracheal tube over the proximal end of the bougie.
  • As the proximal tip of the bougie is re-exposed, the assistant should carefully grasp it, assuming control of the bougie and passing control of the ET tube to the intubator.
  • The ET tube should then be carefully advanced ('rail-roaded') along the bougie and hence through the glottic opening, taking care to avoid movement of the bougie. iv) SUCCESSFUL INTUBATION MAY BE CONSIDERABLY ENHANCED BY ROTATING THE ET TUBE 90º ANTI-CLOCKWISE, SO THAT THE BEVEL FACES POSTERIORLY. In so doing the bougie may also rotate along the same plane but should not be allowed to move up or down the trachea.
• Once the ET tube is fully in place hold it securely as your colleague withdraws the bougie.
• Withdraw the laryngoscope.

10) Inflate the cuff without delay. Then verify correct positioning of the ET tube using auscultation of the lung fields and epigastrium and observing for chest wall movement.

11) Tie the tube securely into place. The tip of the ET tube can move up to 6.0 cm once placed and this is certainly sufficient to dislodge it from the trachea.

12) Position an appropriately sized oro-pharyngeal airway alongside the ET tube to serve as a bite block should the patient's level of consciousness change.

Special circumstances
Single-handed technique for use of bougie Proceed as above but:

• Curve the bougie and ensure the distal tip is formed into a J (coudé) shape.
• Pass the ET tube over the proximal end of the bougie.
• Hold the ET tube and the bougie together at the distal end of the ET tube.
• Perform a laryngoscopy and proceed to advance the bougie as described above, maintaining a secure hold at the distal end of the ET tube.
• Once the bougie is in position advance the ET tube over the bougie until it is in place. Great care must be taken not to displace the bougie.
• Holding the ET tube securely in place, remove the Laryngoscope and then the bougie.
• Continue as above.

Regurgitation
Where there is a high risk of regurgitation, or where liquid from the stomach continuously obscures the glottis despite suction, an assistant should apply Sellick's manoeuvre. This differs from crico-thyroid pressure in that a hand must be placed under the neck as well as on the cricoid cartilage. This action helps to compress the oesophagus to minimise the risk of regurgitation, and has the additional benefit of bringing an anterior glottis into view. SELLICK'S MANOEUVRE MUST NOT BE DISCONTINUED UNTIL THE ET TUBE HAS BEEN CORRECTLY POSITIONED AND THE CUFF INFLATED.

This technique requires either a third assistant or the intubator must use the single-handed technique as described above.

Laryngeal oedema
Rarely, laryngeal oedema due to burns or anaphylaxis will be so severe as to result in swelling which obliterates the glottic opening. When nothing but inflamed swollen tissue is visible on laryngoscopy, instruct an assistant to push down slowly on the chest AND MAINTAIN THE COMPRESSION. This may result in a bubble of air becoming visible over the (hidden) glottis. Pass a bougie through the bubble and it should enter the larynx. Passage of an ET tube over the bougie should now be possible. Initial insertion of a bougie will facilitate trying various sizes of ET tube in the event of difficulty as the bougie can remain in position until success is achieved.

Bibliography

Pitt, K., Woollard, M. Should paramedics bougie on down? (Note: I think so) Pre-hospital Immediate Care. 2000;4:68-70.

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