Upper cervical spine movement during intubation: fluoroscopic comparison of the AirWay Scope, McCoy laryngoscope, and Macintosh laryngoscope

BACKGROUND: The AirWay Scope (AWS) is a new fibreoptic intubation device, which allows visualization of the glottic structures without alignment of the oral, pharyngeal, and tracheal axes, and thus may be useful in patients with limited cervical spine (C-spine) movement. We fluoroscopically evaluated upper C-spine movement during intubation with the AWS or Macintosh or McCoy laryngoscope. METHODS: Forty-five patients, with normal C-spine, scheduled for elective surgery were randomly assigned to one of the three intubation devices. Movement of the upper C-spine was examined by measuring angles formed by adjacent vertebrae during intubation. Time to intubation was also recorded. RESULTS: Median cumulative upper C-spine movement was 22.3 degrees, 32.3 degrees, and 36.5 degrees with the AWS, Macintosh laryngoscope, and McCoy laryngoscope, respectively (P<0.001, AWS vs, Macintosh and McCoy). The AWS reduced maximum movement of the C-spine at C1/C2 in comparison with the Macintosh or McCoy laryngoscope (P=0.012), and at C3/C4 in comparison with the McCoy laryngoscope (P=0.019). Intubation time was significantly longer in the AWS group than in the Macintosh group (P=0.03). CONCLUSIONS: Compared with the Macintosh or McCoy laryngoscope, the AWS produced less movement of upper C-spine for intubation in patients with a normal C-spine.