Effect of head position on the success rate of blind intubation using intubating supraglottic airway devices

Background: To evaluate the effect of head position on the performance of intubating supraglottic airway devices, we compared the success rate of blind intubation in the head-elevated and the pillowless head positions with the LMA Fastrach and the air-Q, and the change of glottic visualization through the air-Q. Methods: We assigned 193 patients to two groups according to the device used and subgrouped by head position used for intubation: Fastrach/pillowless, Fastrach/head-elevated, air-Q/pillowless, and air-Q/head-elevated. Blind intubation through the Fastrach or the air-Q was attempted up to twice after induction of general anesthesia. Before the attempt at blind intubation with the air-Q, the percentage of glottic opening (POGO) score was also fiberscopically evaluated at the outlet of the device in both head positions in a cross-over fashion. Results: The Fastrach significantly facilitated blind intubation compared with the air-Q in both the pillowless and head-elevated positions: 87.2% in Fastrach/pillowless vs 65.9% in air-Q/pillowless (P = .048), 90% in Fastrach/head-elevated vs 53.7% in air-Q/head-elevated (P < .001). The head-elevated position did not significantly affect the success rate of blind intubation for either device (P = .97 in Fastrach, P =. 37 in air-Q). Although the head-elevated position significantly improved the POGO score from the median (10-90 percentile) 60% (0-100%) in the pillowless position to 80% (0-100%) ( P =.008), it did not contribute to successful blind intubation with the air-Q. Conclusion: Although the head-elevated position improved glottic visualization in the air-Q, the head position had minimal influence on the success rate of blind intubation with either the Fastrach or the air-Q. (C) 2016 Elsevier Inc. All rights reserved.