Validating the ‘laryngeal handshake’: a prospective observational study

Abstract

Palpation of the airway structures results in misidentification of the cricothyroid membrane (CTM) in a high proportion of patients.1 The ‘laryngeal handshake’ is advocated by the Difficult Airway Society (DAS) as the method of identifying the CTM in the event of cricothyroidotomy.2,3 This is not yet validated in the literature. We sought to investigate the accuracy of this technique in a female population. We recruited 45 female patients attending for routine gynaecological surgery. Five clinicians at different levels of training performed nine individual patient assessments each. In a simulated ‘cannot intubate and cannot oxygenate’ scenario, the CTM was identified using the laryngeal handshake technique (Group L) with the patient in the head extended position under general anaesthesia. We measured and analysed the distance to actual CTM using ultrasound, the time to identification, and perceived difficulty using a visual analogue scale (VAS). We compared these data to conventional palpation technique by the same physicians in a group of 45 controls (Group P). Successful identification of the CTM occurred in 28/45 patients in Group L vs 15/45 in Group P (P<0.01). Distance to the CTM (P<0.01) and VAS (P<0.01) were significantly reduced in Group L. Mean time to CTM identification was longer in Group L at 31 (SD 5.6) sec, compared to Group P which took 18 (SD 5.5) sec (P<0.01). 39/45 of Group L assessments were deemed to be within the midline vs. 28/45 in Group P (P<0.01). The laryngeal handshake method of palpation is an easily learned technique that provides a more robust tactile appreciation of the underlying cartilaginous structures vs conventional palpation. A high degree of reliability in accurately determining the midline using this method allows greater confidence in utilising the vertical incision currently recommended by DAS if no membrane can be identified. 1.Campbell M, Shanahan H, Ash S, Royds J, Husarova V, McCaul C. BMC Anesthesiol 2014; 2214: 1082.Levitan RM. Cricothyrotomy|Airway Cam—airway management education and training. Available from http://www.airwaycam.com/cricothyrotomy (accessed 30 October 2017)3.Frerk C, Mitchell VS, McNarry AF, et al. Br J Anaesth 2015; 115: 827–48