Identifying the Cricothyroid Membrane: A Comparison of Palpation, Laryngeal Handshake and Ultrasound Background

Bowness, J., Taylor, A., Le Saint-Grant, A., Dalton, A., Crawley, S., Chisholm, F., Varsou, O. , Teoh, W.H., Kristensen, M. and McGuire, B. (2019) Identifying the Cricothyroid Membrane: A Comparison of Palpation, Laryngeal Handshake and Ultrasound Background. World Airway Management Meeting, Amsterdam, The Netherlands, 13-16 Nov 2019.

Abstract

Publications have demonstrated limitations in identifying the cricothyroid membrane (CTM) by palpation (P; <40% accurate),1 and superiority of laryngeal handshake (LH; 62%) and ultrasound (US; >90%).12 We compared the accuracy, confidence and speed of these techniques when employed by experienced operators and novices. Ethical approval was provided by the University of St Andrews, School of Medicine, Ethics Committee. Three medical students (with no prior teaching or experience in using ultrasound) and three anaesthetists underwent three hours of formal training, including a structured step-by-step approach to all techniques. They were then asked to identify the CTM in 11 female simulated patients (SPs). Using a randomised pattern, SPs were serially assessed until all techniques had been used by all operators on all SPs. Accuracy was determined by comparison to ultrasound assessment by two experts. Operators were asked to rate their confidence (0 - 10) after each assessment, and each was timed. There was no statistically significant difference in accuracy of any method overall (P 69.7% vs LH 61.12% vs US 77.27%; p = 0.187). Operators were significantly more confident using ultrasound compared to palpation (6.67 vs 5.88; p = 0.019), but took significantly longer than with palpation or laryngeal handshake (69.58 sec vs 36.65 vs 39.20; p <0.001). Experienced operators were significantly quicker (37.88 vs 59.07 sec, p <0.001) and more confident (6.52 vs 5.92, p = 0.011), but no more accurate (73.74% vs 65.66%, p = 0.279). There was no statistically significant difference in accuracy, confidence or speed between the two operator groups for any technique (palpation, laryngeal handshake or ultrasound). Conventional palpation, after formal training, may be more successful than previously reported. Despite increased confidence associated with ultrasound, this technique was no more successful and took longer. Experienced operators were significantly quicker when performing assessments, and more confident, but no more accurate. Arguably, ultrasound is best used prior to commencing airway management, potentially in conjunction with another method of assessment. References: 1. Drew T, McCaul CL. Br J Anaesth 2018; 121 (5): 1173-1178. 2. Kristensen MS, Teoh WH, Rudolph SS. Br J Anaesth 2016; 117 (S1): i39-i48. Funding: This work was funded by the Scottish Airway Group.

• Item Type: Conference or Workshop Item
• Additional Information: Abstract published in Trends in Anaesthesia and Critical Care 30:e56, https://doi.org/10.1016/j.tacc.2019.12.139
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Varsou, Dr Ourania
• Authors: Bowness, J., Taylor, A., Le Saint-Grant, A., Dalton, A., Crawley, S., Chisholm, F., Varsou, O., Teoh, W.H., Kristensen, M., and McGuire, B.
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences

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