Randomized crossover trial comparing cervical spine motion during tracheal intubation with a Macintosh laryngoscope versus a C-MAC D-blade videolaryngoscope in a simulated immobilized cervical spine

Abstract

Background: Maintaining cervical immobilization is essential during tracheal intubation in patients with unstable cervical spines. When using the Macintosh laryngoscope for intubation in patients with cervical immobilization, substantial neck extension is required for visualization of the glottis. However, the C-MAC D-Blade videolaryngoscope may require less neck extension due to its acute angulation. We hypothesized that C-MAC D-Blade videolaryngoscopic intubation would result in less cervical spine movement than Macintosh laryngoscopic intubation. We compared the effects of C-MAC D-Blade videolaryngoscopic intubation and Macintosh laryngoscopic intubation in terms of cervical spine motion during intubation in patients with simulated cervical immobilization. Methods: In this randomized crossover study, the cervical spine angle was measured at the occiput-C1, C1-C2, and C2-C5 segments before and during tracheal intubation with either a C-MAC D-Blade videolaryngoscope or Macintosh laryngoscope in 20 patients, with application of a neck collar for simulated cervical immobilization. Cervical spine motion was defined as the change in angle measured before and during tracheal intubation. Results: The cervical spine motion at the occiput-C1 segment was measured at 12.1 ± 4.2°and 6.8 ± 5.0°during Macintosh laryngoscopic and C-MAC D-blade videolaryngoscopic intubation, respectively, corresponding to a 44% reduction in cervical spine motion when using the latter device (mean difference, − 5.3; 98.33% CI: − 8.8 to − 1.8; p = 0.001). However, there was no significant difference between the two intubation devices at the C1-C2 segment (− 0.6; 98.33% CI: − 3.4 to 2.2; p = 0.639) or C2-C5 segment (0.2; 98.33% CI: − 6.0 to 6.4; p = 0.929). Conclusions: The C-MAC D-Blade videolaryngoscope causes less upper cervical spine motion than the Macintosh laryngoscope during tracheal intubation of patients with simulated cervical immobilization. Trial registration: This study was registered at ClinicalTrials.gov on June 26, 2018 (NCT03567902).

Effects of External Laryngeal Manipulation on Cervical Spine Motion during Videolaryngoscopic Intubation under Manual In-Line Stabilization: A Randomized Crossover Trial

“…All lateral cervical spine radiographs were automatically saved in the Picture Archiving and Communication System (IFINITT PACS version 5.0.0.143, Infinitt Healthcare, Seoul, Korea) and analyzed by an anesthesiologist who did not know the study hypothesis and the group allocation. The reference lines of the occiput and C1 were defined as a line connecting the sellar base and the opisthion and a line connecting the inferior cortical margin of the C1 anterior arch and the inferior cortical margin of the C1 spinous process, respectively (Figure 1) [15,16,27]. The reference lines of C2, C4, and C5 were defined as a line connecting the antero-inferior cortical margin of the C2 body and the inferior cortical margin of the C2 spinous process and lines parallel to the endplate of the C4 and C5 body, respectively [15,16,27].…”

“…The reference lines of the occiput and C1 were defined as a line connecting the sellar base and the opisthion and a line connecting the inferior cortical margin of the C1 anterior arch and the inferior cortical margin of the C1 spinous process, respectively (Figure 1) [15,16,27]. The reference lines of C2, C4, and C5 were defined as a line connecting the antero-inferior cortical margin of the C2 body and the inferior cortical margin of the C2 spinous process and lines parallel to the endplate of the C4 and C5 body, respectively [15,16,27]. Four cervical spine angles before and during intubation were measured between the reference lines of the occiput and C1, C1 and C2, C2 and C5, and C4 and C5.…”

“…respectively (Figure 1) [15,16,27]. The reference lines of C2, C4, and C5 were defined as a line connecting the antero-inferior cortical margin of the C2 body and the inferior cortical margin of the C2 spinous process and lines parallel to the endplate of the C4 and C5 body, respectively [15,16,27].…”

“…respectively (Figure 1) [15,16,27]. The reference lines of C2, C4, and C5 were defined as a line connecting the antero-inferior cortical margin of the C2 body and the inferior cortical margin of the C2 spinous process and lines parallel to the endplate of the C4 and C5 body, respectively [15,16,27]. Four cervical spine angles before and during intubation were measured between the reference lines of the occiput and C1, C1 and C2, C2 and C5, and C4 and C5.…”

“…Moreover, various videolaryngoscopes are known to produce smaller cervical spine motion during intubation than direct laryngoscopes [6,8,9,11,14]. However, it is inevitable that some degree of cervical spine motion will occur during videolaryngoscopic intubation even under cervical immobilization [6,8,9,11,[14][15][16][17][18]. This is because the force required to lift the videolaryngoscope causes cervical spine motion during intubation, although it is smaller than the force required to lift the direct laryngoscope [19][20][21][22].…”