A comparison of four techniques for the management of unanticipated difficult intubation performed on a high fidelity adult manikin

Thirty volunteer anaesthetists each performed endotracheal intubation on an adult manikin in an unanticipated difficult airway scenario,using four different techniques in a random order. The four techniques were: (A) blind endotracheal intubation via a classic Laryngeal Mask Airway (cLMA) (B) endotracheal intubation over an Aintree Intubation Catheter (AIC) inserted blindly via a cLMA (C) endotracheal intubation over an AIC inserted using a fibreoptic scope (FOS) via a cLMA (D) blind endotracheal intubation via an intubating LMA (iLMA). We recorded success or failure of each technique and length of time taken to successfully achieve placement of a cuffed endotracheal tube (ETT). We also recorded the preferred technique for each volunteer and collected feedback comments. Endotracheal intubation was achieved by 47% of anaesthetists using technique A, 53% using technique B, and 100% using techniques C and D. The times to successful intubation for the four techniques were significantly different. When successful, technique A was significantly faster than techniques B, C and D by 23, 64 and 42 seconds respectively. Technique B was also significantly faster than techniques C and D by 41 and 19 seconds respectively, whilst technique D was faster than technique C by an average of 22 seconds. We conclude that techniques C and D were comparable in terms of time required and were the only reliable methods of achieving intubation. Technique C (cLMA followed by AIC mounted over FOS) was the preferred option of almost two thirds of the anaesthetists who participated in the study.