Cervical spine motion during videolaryngoscopic intubation using a Macintosh-style blade with and without the anterior piece of a cervical collar: a randomized controlled trial.

Purpose: Applying a cervical collar during videolaryngoscopic intubation can increase the lifting force required to achieve adequate glottic view, potentially increasing cervical spine motion. We aimed to compared cervical spine motion during videolaryngoscopic intubation between applying only the posterior piece (posterior-only group) and applying both the anterior and posterior pieces (anterior-posterior group) in patients wearing a cervical collar.

Methods: We conducted a dingle-centre, parallel-group, randomized controlled trial in 102 patients (each group, N = 51). We used a videolaryngoscope (AceScope™, Ace Medical, Seoul, Republic of Korea) with a Macintosh-style blade (AceBlade™, Ace Medical, Seoul, Republic of Korea) for videolaryngoscopic intubation. In each group (posterior-only vs anterior-posterior), we measured cervical spine motion during intubation, defined as change in cervical spine angle (calculated as cervical spine angle at intubation minus that before intubation) at three cervical spine segments on lateral cervical spine radiographs.

Results: The differences in mean cervical spine motion during intubation between the posterior-only and anterior-posterior groups were 1.2° (98.3% confidence interval [CI], -0.7 to 3.0), 1.0° (98.3% CI, -0.6 to 2.6), and -0.3° (98.3% CI, -2.2 to 1.7) at the occiput-C1, C1-C2, and C2-C5 segments, respectively. Mean (standard deviation) cervical spine angles at the occiput-C1, C1-C2, and C2-C5 segments in the posterior-only vs anterior-posterior groups were 10.8° (4.2) vs 9.6° (3.3) (P = 0.13), 5.6° (3.0) vs 4.7° (3.5) (P = 0.14), and 1.2° (3.7) vs 1.5° (4.3) (P = 0.74), respectively. Intubation times were shorter in the posterior-only group (median [interquartile range], 23 [19-28] sec vs 33 [20-47] sec; P = 0.003).

Conclusions: In patients wearing a cervical collar, the differences in mean cervical spine motions during intubation between applying only the posterior piece and applying both the anterior and posterior pieces were approximately 1°. Intubation times were significantly shorter without the anterior piece of a cervical collar. These findings can be referred to when removal of the anterior piece of a cervical collar is considered to address difficult videolaryngoscopic intubation conditions.

Study registration: CRIS.nih.go.kr ( KCT0008151 ); first submitted 17 January 2023.