Does Increasing the Bend Angle of a Stylet to 90° Increase the Nasotracheal Intubation Success Rate?

Abstract

BackgroundVideo-stylet-guided nasotracheal intubation is an effective technique for airway management. However, the impact of the bend angle on the success rate of intubation remains unclear. PurposeDoes increasing the bend angle of a stylet to 90 degrees increase nasotracheal intubation success rate? Study design, setting, sampleThis prospective randomized controlled trial was conducted in the operating room of a population-based hospital. Adult patients requiring nasotracheal intubation were recruited. Predictor/exposure/independent variableThe primary predictor variable is the choice of stylet bend angle (90° versus 70° bend) in nasotracheal intubation. Main outcome variable(s)The primary outcome variables were success rates of nasotracheal intubation, defined as the proportion of successful intubation cases to total cases. CovariatesDemographics, intubation time, the distance from the thyroid prominence to the nostril, additional maneuvers applied during intubation, and cases of epistaxis were recorded. AnalysesThe student’s t-test was used to compare continuous variables between groups. Ordinal data (intubation attempts, head extension, and epistaxis) were analyzed using the Wilcoxon rank-sum test. As appropriate, frequency (external pharyngeal pressure) was analyzed using the chi-square test or Fisher’s exact test. A p-value of <0.05 was considered statistically significant. ResultsOf the 103 subjects assessed for eligibility, 98 were enrolled in the study. The mean age (27.0±6.9 years vs. 27.0±4.1 years, p=0.972) and sex differences (male/female: 9/40 vs. 7/42, p=0.136) were comparable between groups. The overall success rate in the 70° group was significantly lower than that in the 90° group (91.8% vs. 100%, p<0.001). The intubation time in the 70° group was significantly longer than that in the 90° group (43.2±15.8 s vs. 33.7±7.3 s, p<0.001). Conclusions and RelevanceA 90° bend angle of the stylet significantly improves the likelihood of successful nasotracheal intubation.