Blade Size and Outcomes With Standard-Geometry Video Laryngoscopy in Emergency Tracheal Intubations: Secondary Analysis of 2 Randomized Controlled Trials
Background: Laryngoscope blade size may affect successful intubation on the first attempt, but evidence to inform the optimal blade size for standard-geometry curved video laryngoscopes (VLs) in critically ill adults is limited. Research Question: Does the use of a size 3 vs size 4 standard-geometry curved VL blade affect outcomes of tracheal intubation in critically ill adults? Study Design and Methods: We performed a secondary analysis of data from 2 multicenter randomized trials conducted in ICUs and emergency departments (EDs) in the United States. We included adult patients who, on the first intubation attempt, received a standard-geometry curved VL blade of size 3 or 4. The primary outcome was the incidence of successful intubation on the first attempt. Secondary outcomes included the duration of the procedure, the lowest oxygen saturation, the incidence of severe hypoxemia, glottic view, and exploratory clinical outcomes. We used propensity score-based inverse probability of treatment weighting (IPTW) to adjust for baseline differences between groups. Results: Of 1,220 patients, 517 patients (42%) were intubated with a size 3 blade and 703 patients (58%) were intubated with a size 4 blade. After IPTW adjustment, patients intubated with a size 3 blade and a size 4 blade did not differ regarding the incidence of successful intubation on the first attempt (84.6% vs 87.6%, respectively; adjusted OR, 0.78; 95% CI, 0.54-1.14). Procedure duration was similar (38.4 seconds vs 39.1 seconds; aHR, 0.97; 95% CI, 0.85-1.10). Complications and exploratory outcomes were comparable between groups. Interpretation: Our results show that among critically ill adults undergoing emergency tracheal intubation with standard-geometry VLs, blade size (3 vs 4) was not associated with first-pass success or other major procedural and clinical outcomes.
