Effects of an elevated position on time to tracheal intubation by novice intubators using Macintosh laryngoscopy or videolaryngoscopy: randomized crossover trial

OBJECTIVE To investigate the time to tracheal intubation using Glidescope videolaryngoscopy (GVL) compared to that of standard laryngoscopy, by using a Macintosh blade (SLM) in a human patient simulator in supine and elevated (ramped) positions. METHODS In this randomized crossover design, novice intubators (first-year medical students), using both laryngoscopic techniques, attempted tracheal intubation on a human patient simulator with a "normal airway" anatomy (Cormack-Lehane grade I). The simulator was placed in both supine and ramped positions using a commercial mattress system. The mean time to intubation and complications were compared between GVL and SLM in both positions. The percentage of glottic opening (POGO, GVL only) was estimated during intubation in the ramped and supine positions. The primary outcome was time to intubation, and the secondary outcomes included complication rates such as esophageal intubation and dental trauma. RESULTS There was no difference in the mean time to intubation in either position (P=0.33). The SLM intubation was significantly faster than GVL (mean difference, 1.5 minutes; P<0.001). The mean POGO score for GVL improved by 8% in the ramped position compared to that in supine position (P=0.018). The esophageal intubation rate for SLM was 15% to 17% compared to 1.3% for GVL; dental trauma occurred in 53% to 56% of GVL, compared to 2% to 6% for SLM (P<0.001, respectively). CONCLUSION Novices had shorter intubation times using standard laryngoscopy with a SLM compared to GVL in both supine and ramped positions. GVL resulted in fewer esophageal intubations, but more dental trauma than standard laryngoscopy.