Effect of head-elevated versus neutral position on tracheal intubation using a hyper-angulated video laryngoscope under cervical spine immobilization: a randomised crossover trial.

BACKGROUND

Videolaryngoscopes with hyper-angulated blades improve glottic visualisation in patients with cervical spine immobilisation but may complicate blade insertion and tracheal tube (TT) advancement. We compared the head-elevated (HE) and head-neutral (HN) position during GlideScope®-guided intubation under manual in-line stabilisation (MILS).

METHODS

In this randomised crossover trial, 180 adult patients undergoing elective surgery were allocated to HN or HE groups. Under MILS, videolaryngoscopy was performed in both positions, but intubation was attempted only in the second designed position. The HE position was achieved by elevating the back section of the table to align the external auditory meatus and sternal notch.

RESULTS

Intubation was attempted in 177 patients with 100% success. Median intubation time was shorter in HE group than HN group (27.2 [23.4-34.3] vs. 31.5 [27.0-40.5] s; difference -4.5 s, 95% CI -7.5 to -1.8; P =  0.001). The modified intubation difficulty scale was lower in HE group (1 [0-1]) than HN group (2 [1-3]; P <  0.001). The need for optimisation manoeuvres was less frequent in the HE position for GlideScope® blade insertion (5.6% vs. 13.9%; P =  0.0001) and for TT advancement (31.8% vs. 58.4%; P <  0.001). Laryngeal view was superior in the HE position, with a higher mean percentage of glottic opening score (42.9 ± 35.6% vs. 26.8 ± 32.3%; P < 0.0001) and a greater proportion of easy modified Cormack-Lehane grades (83.8% vs. 64.8%; P < 0.0001).

CONCLUSION

The HE position significantly improved intubation efficiency and technical ease using a hyper-angulated videolaryngoscope under MILS.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05671978.