Comparison of supine and upright face-to-face cadaver intubation

Optimal patient positioning during intubation improves laryngeal view and first pass success, as well as reducing incidence of hypoxia. In certain pre-hospital situations, it may be impractical or impossible for the operator to stand behind the patient.

We compared intubation in the supine and upright face-to-face positions, with regards to time to intubate and the view of the vocal cords obtained.

This was a pilot comparison study. One investigator intubated 25 cadavers with the use of a bougie in the supine and upright face-to-face positions. Each attempt was recorded on a video laryngoscope. Recordings of each attempt were reviewed by five blinded emergency physicians, who allocated both a percentage of glottic opening (POGO) score and Cormack-Lehane (CL) grade. Time to insertion of the endotracheal tube (ETT) through the vocal cords was measured from the video.

The median intubation time was 1 s longer for upright cadavers than for supine cadavers, with greater variation in intubation times for upright cadavers compared with supine cadavers (IQR 9.0 vs 3.5 excluding the outlier case). The mean POGO score (averaged across raters) was 4.7% lower for upright intubation attempts (excluding the outlier case) with a moderate-to-good degree of inter-rater reliability, however this difference was not statistically significant. The median CL grade (averaged across raters) was 0.2 higher for upright intubation attempts (excluding the outlier case) with a poor-to-moderate degree of inter-rater reliability, and this difference was also not statistically significant.

This pilot study suggests that upright, face-to-face intubation may be clinically similar to supine intubation in terms of time to intubation and difficulty. Further studies utilising a larger number of operators and cadaver types are indicated.