Comparison of the Bonfils and Levitan optical stylets for tracheal intubation: a clinical study

The Bonfils and Levitan FPS scopes are rigid fibreoptic stylets that may assist routine or difficult intubation. This study compared the effectiveness of each in patients with predicted normal airways when used by specialist anaesthetists with no prior experience using optical stylets. Twelve anaesthetists and 324 elective surgical patients participated. Six anaesthetists were randomised to first intubate 20 patients with the Levitan scope (Phase 1) followed by a further seven patients with the Bonfils scope (Phase 2). The other six participating anaesthetists undertook their first 20 intubations with the Bonfils (Phase 1), followed by seven intubations with the Levitan (Phase 2). Outcomes recorded were success rate, total time to intubation, number of attempts, ease of intubation score and incidence of complications. Overall failure rates were similar for the two scopes with 5.6% of patients not intubated after three attempts. Median total times to intubation were similar for the Levitan (44 seconds) and Bonfils (36 seconds) (P = 0.11). Participants using the Bonfils in Phase 1 had significantly higher chance of success on first attempt (73%) compared to Levitan users during Phase 1 (57%) (P = 0.008). These differences were not significant in the second phase and ease of intubation scores were similar for both scopes (P = 0.9). This study showed the two scopes were comparable but the high failure rate amongst novice users demonstrated the importance of familiarity and skill development prior to their introduction to a difficult airway cart.