Randomised comparison of the effectiveness of the laryngeal mask airway supreme, i-gel and current practice in the initial airway management of out of hospital cardiac arrest: a feasibility study

Background: The best initial approach to advanced airway management during out of hospital cardiac arrest (OHCA) is unknown. The traditional role of tracheal intubation has been challenged by the introduction of supraglottic airway devices (SGAs), but there is contradictory evidence from observational studies. We assessed the feasibility of a cluster-randomized trial to compare the i-gel SGA vs the laryngeal mask airway supreme (LMAS) vs current practice during OHCA.

Methods: We conducted a cluster-randomized trial in a single ambulance service in England, with individual paramedics as the unit of randomization. Consenting paramedics were randomized to use either the i-gel or the LMAS or usual practice for all patients with non-traumatic adult OHCA, that they attended over a 12-month period. The primary outcome was study feasibility, including paramedic and patient recruitment and protocol adherence. Secondary outcomes included survival to hospital discharge and 90 days.

Results: Of the 535 paramedics approached, 184 consented and 171 attended study training. Each paramedic attended between 0 and 11 patients (median 3; interquartile range 2-5). We recruited 615 patients at a constant rate, although the LMAS arm was suspended in the final two months following three adverse incidents. The study protocol was adhered to in 80% of patients. Patient characteristics were similar in the three study arms, and there were no differences in secondary outcomes.

Conclusion: We have shown that a prospective trial of alternative airway management strategies in OHCA, cluster randomized by paramedic, is feasible.

Clinical trial registration: Registered on the International Standard Randomised Controlled Trial Registry (

Isrctn: 18528625).