Intubation of non-difficult airways using video laryngoscope versus direct laryngoscope: a randomized, parallel-group study

BACKGROUND: The video laryngoscope is recommended for intubating difficult airways. The present study aimed to determine whether the video laryngoscope can further improve intubation success rates compared with the direct laryngoscope in patients with non-difficult airways. METHODS: In total, 360 patients scheduled for elective abdominal surgeries were randomly assigned to undergo intubation using either a video laryngoscope (n = 179) or a direct laryngoscope (n = 181). The following parameters were measured: mouth opening; thyromental distance; sternomental distance; shape angle of the tracheal catheter; and glottic exposure grade. RESULTS: The percentage of patients with level I-II of total glottic exposure in the video laryngoscope group was 100% versus 63.5% in the direct laryngoscope group (P < 0.001). The one-attempt success rate of intubation was 96.1% using a video laryngoscope versus 90.1% using a direct laryngoscope (P = 0.024). The intubation success rate using a video laryngoscope was 100% versus 94.5% using a direct laryngoscope (P = 0.004). Immediate oropharyngeal injury occurred in 5.1% of patients intubated using a direct laryngoscope versus 1.1% using a video laryngoscope (P = 0.033). On postoperative day 1, obvious hoarseness was exhibited by 7.9% of patients intubated using a direct laryngoscope versus 2.8% using a video laryngoscope (P = 0.035). The grade of glottic exposure and catheter shape angle were independent risk factors for tracheal intubation failure. Thyromental distance, shape angle, glottic exposure time, and surgical position were independent risk factors for postoperative complications. Thyromental distance and glottic exposure time were independent risk factors for complications lasting > 2 days. CONCLUSIONS: Intubation using a video laryngoscope yielded significantly higher intubation success rates and significantly fewer postoperative complications than direct laryngoscopy in patients with non-difficult airways. TRIAL REGISTRATION: Chinese Clinical Trial Registry. No: ChiCTR-IOR-16009023 . Prospective registration.