Effects of the head-elevated position on cervical spine motion during videolaryngoscopic intubation with manual in-line stabilization: a randomized controlled trial.

Purpose: The head-elevated position during videolaryngoscopic intubation enables better visualization of the glottis than the head-flat position. We hypothesized that the head-elevated position would result in less cervical spine motion during videolaryngoscopic intubation under manual in-line stabilization.

Methods: We conducted a randomized controlled trial in which we assigned patients undergoing coil embolization for unruptured cerebral aneurysms into the head-elevated (N = 55) or head-flat (N = 54) groups. Manual in-line stabilization was applied to simulate cervical spine immobilization during Macintosh-type videolaryngoscopic intubation. To measure the cervical spine angle, two lateral cervical spine radiographs using the capture method were taken, one before and one during intubation, respectively. The primary outcome was cervical spine motion during intubation (cervical spine angle during intubation - cervical spine angle before intubation) at the occiput-C1 segment. We investigated cervical spine motion at the C1-C2 and C2-C5 segments; intubation performance, such as the success rate at the first attempt, intubation time, and frequency of external laryngeal maneuver; and intubation-associated airway complications (airway bleeding, injury, sore throat, and hoarseness).

Results: There was significantly less cervical spine motion at the occiput-C1 segment in the head-elevated group than the head-flat group (mean [standard deviation], 8.6° [5.6°] vs 11.4° [5.7°]; mean difference [95% confidence interval], -2.9° [-5.0 to -0.7]; P = 0.009). Cervical spine motion at the C1-C2 and C2-C5 segments, intubation performance, and intubation-associated airway complications did not significantly differ between the groups.

Conclusions: The head-elevated position during Macintosh-type videolaryngoscopic intubation with manual in-line stabilization resulted in less upper cervical spine motion than the head-flat position.

Study registration: CRIS.nih.go.kr ( KCT0008669 ); date of registration (approved), 1 August 2023.