Effects of Passive Head-and-Neck Movements on the Performance of i-gel(®) Supraglottic Airway Device in Anesthetized Patients – A Randomized Crossover Trial

BACKGROUND: Passive movements of head and neck are sometimes unavoidable during surgery under general anesthesia due to patient positioning according to the needs of the surgery or transmitted movements from surgical manipulations. AIMS: This prospective crossover randomized study evaluates the effects of passive movements of the head and neck on the performance of i-gel(®) supraglottic airway device in spontaneously breathing patients under general anesthesia. MATERIALS AND METHODS: Sixty spontaneously breathing patients on pressure support ventilation with positive end-expiratory pressure (PEEP) under general anesthesia were randomized to seven sequences of passive head-and-neck movements with i-gel® in situ. After steady state of general anesthesia was achieved and maintenance with sevoflurane in N(2)O and O(2) was reached, the passive head-and-neck movements were done. Peak airway pressure, exhaled minute volume, end-tidal carbon dioxide (ETCO(2)), oxygen saturation, audible leak of airway gases, and visible outward displacement of the i-gel® were recorded in the neutral position and with each passive head-and-neck movement. Paired continuous data were analyzed by Friedman rank sum test with paired Wilcoxon signed-rank test. Paired nominal data were analyzed by Cochran's Q test with pair-wise McNemar test. RESULTS: Extension, right or left lateral flexion, and right or left rotation of the head and neck resulted in significant reduction in the exhaled minute ventilation, rise in ETCO(2), and leak of airway gases compared to the neutral position (P < 0.05). Flexion movement did not cause significant changes in the exhaled minute ventilation, rise in ETCO(2), and audible leak of airway gases as compared to the neutral position. CONCLUSIONS: Ventilatory performance of the i-gel® deteriorates upon extension, right or left lateral flexion, and right or left rotation of the head and neck in spontaneously breathing patients under general anesthesia on pressure support ventilation with PEEP.