The effect of cricoid pressure application on airway patency.

STUDY OBJECTIVE: To assess the incidence of upper airway obstruction associated with the application of cricoid pressure (Sellick's maneuver) by experienced anesthetists.

DESIGN: Randomized, blinded study.

SETTING: Anesthetic rooms at John Radcliffe Hospital, Oxford, United Kingdom.

PATIENTS: Fifty ASA I patients undergoing routine general anesthesia for elective surgery requiring tracheal intubation.

INTERVENTIONS: Following induction of anesthesia and muscle relaxation, a senior anesthetist applied cricoia pressure in the manner described by Sellick. Patients were ventilated with or without cricoid pressure, with the order of intervention randomized, and the observer blinded to all maneuvers.

MEASUREMENTS AND MAIN RESULTS: Effect on airway patency was assessed by measuring expired tidal volume (VT) and peak inspiratory pressure (PIP) when ventilated using a face mask with and without cricoid pressure applied, and with and without an oropharyngeal airway in place. Application of cricoid pressure caused a significant reduction in mean expired VT (p < 0.001) and a significant increase in PIP (p < 0.001) compared with control values. Complete airway occlusion occurred in 11% of applications.

CONCLUSIONS: The use of manual cricoid pressure, even by experienced anesthetists, causes a degree of airway obstruction and can cause complete airway occlusion.