Effect of Stylet Bend Angle on Endotracheal Intubation Time via Direct Laryngoscopy: A Randomized Crossover Simulation Study

IntroductionProper preparation of stylet angulation is a critical factor for rapid endotracheal intubation. However, clinical guidelines regarding the optimal stylet angulation for this procedure remain undefined.ObjectivesTo study the effect of different endotracheal tube stylet bend angles on intubation time, first-attempt success rate, and intubation failure rate.MethodA randomized crossover simulation study was conducted to compare the effect of various stylet angles on intubation time. Seventy medical personnel with varying levels of experience at Saraburi Hospital participated between January 1st and December 31st, 2025. Participants performed intubations using a randomized sequence of predetermined stylet angles. The primary outcome was intubation duration, while secondary outcomes included the number of attempts and intubation failure rates.ResultsThe adjusted mean time (aMT) for the 15° angle was 18.2 seconds (95% CI, 15.9–20.4). Intubation durations with 30° and 45° stylet bend angles were significantly shorter than with a 15° stylet bend angle (aMT = 15.4 s; 95% CI, 13.1–17.6 and aMT = 15.5 s; 95% CI, 13.2–17.8, respectively), with no intubation failures. In contrast, 75° and 90° angles required significantly longer durations (aMT = 21.1 s; 95% CI, 18.8–23.3 and aMT = 26.0 s; 95% CI, 23.7–28.2, respectively), with a failure rate of 1.4%. First-attempt success rates did not differ significantly across all angles.ConclusionA stylet bend angle of 30°–45° requires the least amount of intubation time in a simulation model when compared to other angles. Stylet angulation does not significantly impact the first-attempt success rate.