Evaluation of a novel cricothyroidotomy introducer in a simulated obese porcine model: a randomised crossover comparison with scalpel cricothyroidotomy

Abstract

The Difficult Airway Society 2015 guidelines for management of unanticipated difficulties in tracheal intubation in adults have generated much discussion regarding Plan D: emergency front-of-neck access with a scalpel-bougie cricothyroidotomy technique. There is concern that this technique may not provide an adequate pathway for the bougie and subsequently the tracheal tube, especially in obese patients with deeper airway structures. This could lead to the formation of a false passage, trauma and failure. A novel cricothyroidotomy introducer, 8 mm wide and 170 mm long, with a sharp leading edge and guiding channel to pass a bougie into the trachea, has been designed to complement the scalpel cricothyroidotomy technique. A comparison study of the use of this novel introducer with the scalpel technique in a simulated obese porcine laryngeal model demonstrated shorter insertion times (median (IQR [range]) 85 (65-123 [48-224]) s vs. 84 (72-184 [46-377]) s, p = 0.030). All 26 (100%) participants successfully performed cricothyroidotomy in the introducer group, whereas only 24 (92%) participants were successful in the scalpel group. The introducer group required fewer attempts to access the trachea compared with the scalpel group (p = 0.046). False passages occurred eight (31%) times in the introducer group compared with 17 (65%) times in the scalpel group (p = 0.022). There were no statistical differences in tracheal trauma (p = 0.490), ease of use (p = 0.220) and device preference (p = 0.240). This novel cricothyroidotomy introducer has shown promising results in securing the airway in an emergency front-of-neck access situation. With robust training, this introducer could potentially be complementary to the scalpel-bougie cricothyroidotomy technique.

Rescue oxygenation success by cannula or scalpel-bougie emergency front-of-neck access in an anaesthetised porcine model

“…Consistent with the findings in the´wet´sheep model of morbidly obese neck, we have not observed any differences in insertion times between the cannula and scalpel-bougie technique [25]. However, when compared to the non-obese or slim-neck animal models, longer insertion times were reported especially for cannula technique [2,13,16,[25][26][27]. In our study, the cannula technique was successfully accomplished in less than 60 seconds in only three animals (27%)…”

“…The increased pretracheal soft tissue depth represents an additional challenge in manually palpating the cricothyroid membrane. As a result, a cricothyroid membrane was punctured in 74% of our animals, which replicated the previous data in pig's larynx simulating the obese neck [26]. The cricothyroid membrane identification can be improved by the use of ultrasonography.…”

“…Nevertheless, the mandatory perpendicular bougie introduction in the obese model made the insertion of coudé tip difficult which we overcame by bougie manipulation along its long axis. Using a novel cricothyroidotomy introducer invented to slide the bougie into the trachea may be of assistance in this case [26]. Our findings are therefore in contradiction to those obtained in a slim neck ovine model [16] suggesting that the pre-tracheal tissue thickness needs to be taken into consideration when deciding on the optimal eFONA technique in the patient [5].…”

Time to oxygenation for cannula‐ and scalpel‐based techniques for emergency front‐of‐neck access: a wet lab simulation using an ovine model

“…These 11 failures using the scalpel‐bougie technique contrast with the cannula technique where simple manoeuvres or a second attempt often resulted in success after an initial failure. A high rate of false passage of bougie and tracheal tube (65%) has been shown in an obese porcine benchtop model using a scalpel‐bougie technique . The chance of false passage increases when the trachea is found deep within tissues (as occurs in obesity) which is relevant to the difficult airway .…”

Statistical significance comparing cricothyroidotomy techniques

“…Yeow et al. found a median one‐second difference in time to insertion of a tracheal tube with successful ventilation using a novel cricothroidotomy introducer compared with scalpel cricothroidotomy (85 s vs. 84 s, respectively) . However, despite the novel introducer having the greater median, the authors concluded its insertion was faster, with a p value (Wilcoxon's Signed Ranks (WSR) test) of 0.030.…”