A comparison of simulated difficult intubation with multiple-use and single-use bougies in a manikin*


  • *

    Presented in part at the Difficult Airway Society Annual Scientific Meeting, Oxford, 2001 and the European Society of Anaesthesiologists Annual Meeting, Nice, 2002.

Correspondence to: I. P. Latto


Summary In a randomised cross-over study, 20 anaesthetists attempted to place a multiple- or single-use bougie in the trachea of a manikin, in which a grade 3 Cormack and Lehane laryngoscopic view was simulated. The anaesthetists made two attempts at placement with each bougie and were blinded to success (tracheal placement) or failure (oesophageal placement). The success rates for the first attempts with the multiple- and single-use bougies were 85 and 15%, respectively [mean (95% CI) difference between the two bougies 70% (40–84%); p < 0.001]. The success rates for the second attempts were similar to those for the first attempts with both bougies. There is an increased risk of failure to intubate the trachea when using a single-use bougie, and this must be weighed against the unquantified risk of cross-infection from prions when using a multiple-use bougie.

The multiple-use gum elastic bougie (Eschmann Healthcare Tracheal Tube Introducer, SIMS Portex, Hythe, UK) is widely used in the UK as an aid during difficult intubation [1, 2]. However, concerns have been raised about the possibility of transferring the prions thought to be responsible for causing variant Creutzfeldt-Jakob disease (vCJD) between patients when using multiple-use devices [3]. This is because of the difficulty in ensuring that all microbial and proteinaceous contamination of the device has been removed during cleaning and sterilisation [4, 5]. This has led to a move in favour of single-use devices.

The single-use bougie became available in 1997 (Portex Tracheal Tube Introducer, SIMS Portex). However, this device is significantly different in design and physical characteristics from the multiple-use bougie. The success rate when using the multiple-use bougie for intubation in difficult cases is known [2, 6], but not that when using the single-use bougie. We used a simulated difficult intubation technique in a manikin to compare the success rate for tracheal placement of the two bougies.


The local research ethics committee considered that ethical approval for this study was unnecessary. Twenty anaesthetists, six consultants and 14 trainees of various grades, who were present in the department at the time of the study and who had at least one year's experience of using bougies, were invited to participate. None declined to take part.

A Laerdal Airway Management Trainer was arranged to simulate a grade 3 Cormack and Lehane laryngoscopic view [7, 8]. The laryngoscope blade (size 3) was fixed into position using a retort stand and a clamp (Fig. 1). Each anaesthetist attempted placement of both the single- and multiple-use bougies in the trachea, in random order, according to a program written using labview (Version 2.2.1, National Instruments) running on a PowerMac Macintosh (Apple) to generate the randomisation code. The code ensured that equal numbers of anaesthetists used the single- and multiple-use bougies first. Twelve brand new bougies, six multiple-use and six single-use, were used in rotation. An investigator held the straight bougie at the ends and passed it to the anaesthetist, who was not allowed to manipulate the laryngoscope, alter the head position or apply external laryngeal pressure. A stopwatch was started when the anaesthetist took the bougie. The anaesthetist was able to hold the bougie and shape it as he/she would do in everyday practice before attempting to place it in the trachea. Tracheal intubation over the bougie was not attempted. The anaesthetist placing the bougie was blinded as to whether the bougie was placed in the trachea or in the oesophagus, but this was noted by the investigator. The distance from the tip at which the bougie was held, the number of attempts at shaping the bougie and the time taken to place the bougie were also recorded.

Figure 1.

The Laerdal Airway Management Trainer arranged to simulate a Grade 3 Cormack and Lehane laryngoscopic view.

In a separate experiment, brand new single- and multiple-use bougies (one of each) were bent into curves using a clamp and videoed as they were allowed to straighten, in order to assess their stability after shaping. Still frames were taken from the video at selected times to show the changes in curvature. The images were superimposed using a graphics editor to produce a single composite picture.

The primary outcome measure was the difference in the success rate of tracheal placement of the two bougies, comparing the first attempt with each bougie. An analysis of the success rates with the second attempt with each bougie was used to determine the repeatability of the result. McNemar's test with Yates's correction for continuity was used; the result from this test was compared using the chi-squared distribution with one degree of freedom, taking a value of p < 0.05 to denote statistical significance. Secondary outcome measures were the distance the bougies were held from their tips, the time taken for placement and the number of times that bougies were shaped. Comparisons were with Wilcoxon's signed rank test with the Bonferonni correction to compensate for multiple comparisons, or Fisher's exact test (one-sided as shaping was only likely to improve successful placement).


On both the first and the second attempts with each bougie, the anaesthetists were more likely to place the multiple-use bougie in the trachea than the single-use bougie (Table 1). Three anaesthetists successfully placed both bougies in the trachea on both attempts. Only one anaesthetist in the whole study failed with both bougies on both attempts. The distance held from the tip and the time taken for placement were similar for the two bougies and for the two attempts with each bougie (Table 2). Shaping the bougie did not significantly improve the likelihood of successful placement (Table 3).

Table 1.  Placement of multiple- and single-use bougies during simulated laryngoscopy by 20 anaesthetists. Each anaesthetist had two attempts with each type of bougie. Values are number (%). Mean (95% CI) difference between the two bougies 70% (40–84%) for the first attempt and 55% (27–74%) for the second attempt.
First attempt17 (85)3 (15)3 (15)17 (85)< 0.001
Second attempt17 (85)3 (15)6 (30)14 (70)< 0.01
Table 2.  Distance from the tip at which multiple- and single-use bougies were held by 20 anaesthetists during simulated laryngoscopy and times to placement. Values are median (interquartile range [range]). No significant difference between bougies.
First attempt
Second attemptSingle-use
First attempt
Second attempt
Distance from tip; cm20 (20–22 [10–35])20 (20–20.8 [10–30])20 (20–25 [10–35])20 (20–25 [10–30])
Time to placement; s12.5 (9.3–18.5 [6–38])10.5 (8.3–13.8 [5–41])11 (8.3–18.5 [6–55])12 (8.5–24.5 [3–28])
Table 3.  Effect of shaping on placement of multiple- and single-use bougies by 20 anaesthetists during simulated laryngoscopy (first and second attempts added together). Values are number (proportion). No significant difference between shaped and not-shaped.
Not shapedSingle-use
Not shaped
Tracheal25 (62.5%)9 (22.5%) 9 (22%)0
Oesophageal 2 (5%)4 (10%)23 (57.5%)8 (20%)

Analysis of the video of the bougies revealed that the single-use bougie was straighter than the multiple-use bougie at one second (Fig. 2).

Figure 2.

Cine-film of the single- and multiple-use bougies bent into curves and filmed as they were allowed to straighten in order to test their stability after shaping.


This study clearly shows the superiority of the multiple-use bougie compared with the single-use bougie according to the success rates for tracheal placement, when evaluated using simulated difficult intubation in a manikin.

In the UK, the gum elastic bougie has been widely accepted as an adjunct to managing difficult intubation; 100% of respondents to a recently conducted survey in the UK used the gum elastic bougie as their technique of choice when faced with an unexpected difficult intubation (A. Turley, I.P. Latto, Cardiff airway management audit. Difficult Airway Society Annual Meeting, Cardiff; November 1996). A telephone survey of English emergency departments revealed that 99% of units held gum elastic bougies on their difficult airway equipment trolleys [1]. When faced with unanticipated difficult intubation, the ready availability of a simple, familiar and reliable aid to intubation may be lifesaving.

The success rate for the multiple-use bougie in our study was 85%, for both the first and the second attempt. Previous studies using simulated difficult intubation in patients reported success rates of 96%[6] and 100%[9]. The grade 3 laryngoscopic view in our study was with a Laerdal Airway Management manikin. Participating anaesthetists did not alter the presentation of the airway in any way. The rigidity of the Laerdal model appeared to make insertion of the bougie more difficult, despite the use of lubricant. This may explain the difference in tracheal placement figures for simulated difficult intubation in patients and the manikin. The increase in success rates with the single-use bougie after one attempt, from 15 to 30%, is unlikely to be a learning effect as the anaesthetists were not aware whether the bougie was placed in the trachea or in the oesophagus.

We could find no study investigating whether shaping the gum elastic bougie has any effect on successful placement. In our study, shaping improved the success rates with both bougies but not significantly. We were surprised that in 26% of attempts the bougie was not shaped at all. The authors' clinical practice is to shape the bougie routinely. It is possible that the angle of the tip significantly aided tracheal placement, and this is currently being investigated in another study.

From the side, single- and multiple-use bougies appear to be very similar. Both bougies have a distal end that is angulated at 40°, 3.5 cm from the tip. The assistant might therefore hand the anaesthetist a single-use bougie when the anaesthetist wishes to use a multiple-use bougie. However, the bougies have different physical characteristics. The multiple-use bougie is made of braided Dacron polyester, coated repeatedly in a resin. The single-use bougie is a hollow plastic tube. If the single-use bougie is used (to prevent infection) and there is failure to intubate, the multiple-use bougie should be substituted. On the video, the multiple-use bougie retained the curved shape for longer compared with the single-use bougie (Fig. 2). This may be one of the reasons for the large difference in success rates we found between the bougies. In addition to the lower success rate, the single-use bougie appears to have greater potential for tissue trauma [10].

In 1997, Hill et al. [3] identified prions in tonsillar tissue, highlighting the risk of cross-contamination and iatrogenic transmission of vCJD via re-usable equipment. Although the whole population of the UK has been potentially exposed to vCJD there have been no cases in which there is good evidence that contaminated surgical equipment has been responsible for the spread of the disease [11]. It has been recommended that a single-use bougie should be used to assist intubation before a tonsillectomy operation [12]. However, there would not appear to be any greater risk of contamination of the bougie in these circumstances than for any other operation, as long as the bougie is kept separate from blood and tissue after intubation. Cuppit [4] demonstrated microbial contamination on 45% of re-usable bougies or their storage containers, and commented that use of disposable bougies is cheaper as well as being good clinical practice. In one study, protein deposits were detected on cleaned re-usable equipment [5]. However, before we convert to using single-use devices, we should be provided with evidence of both their efficacy and their safety. The Medical Devices Agency recently warned of the potential problems with single-use devices [13]. The Department of Health has advised a return to re-usable non-disposable equipment for tonsillectomy. The need for mass production of single-use devices has been met by producing cheaper but poorer quality products. These products are often introduced into clinical practice without adequate evaluation of their clinical effectiveness.

The risk of infection should not be ignored; however, the effectiveness and quality of equipment also needs to be considered. The President of the Royal College of Anaesthetists has pointed out that ‘hypoxia threatens lives in minutes, haemorrhage in hours and tonsillar prions (maybe) in decades’[14]. Our study suggests that the single-use bougie is an inferior alternative to the currently used multiple-use bougie, and highlights a need for improved design of the single-use bougie.


We thank Emeritus Professor W. W. Mapleson for his help in preparation of this manuscript.