The learning curve for laryngoscopy: Airtraq versus Macintosh laryngoscopes

Airtraq use by inexperienced personnel has been evaluated in simulator studies, but little is known about the learning process in real patients. This prospective study was designed to compare learning curves for laryngoscopy with the Airtraq or Macintosh laryngoscopes in patients under general anesthesia.

Ten medical students with no prior experience in airway management were recruited on a voluntary basis and underwent training in Macintosh and Airtraq laryngoscopy. Patients with no difficult intubation criteria were enrolled after consent. Each student performed laryngoscopy with either device on ten consecutive patients. Success was defined as Cormack-Lehane grading ≤2. We also recorded subjective difficulty scores on an 11-point numerical rating scale. Learning curves were drawn using cumulative success rates and 95% confidence intervals calculated with bootstrap procedures.

The mean (95% CI) success rates for the procedures were 86.0% (76.7-93.3%) for the Airtraq and 64.0% (52.0-75.0%) for the Macintosh laryngoscope. Differences in success rate were significant from the fourth attempt and were 22.0% (8.2-36.5%) after the tenth. Seven students achieved success rates ≥90% using the Airtraq, versus one using the Macintosh (P = 0.022). Median (25th-75th percentile) difficulty scores were 2 (1-4) and 4 (2-6), respectively (P < 0.001).

Students achieved higher success rates using the Airtraq laryngoscope during early training on live patients. The Airtraq may be a useful choice for teaching advanced airway management, especially to professionals who will not perform laryngoscopy on a regular basis.