Association between video laryngoscope blade geometry and first-pass success during prehospital intubation: a prospective bicentric observational study.

backgroundEndotracheal intubation (ETI) is a cornerstone of advanced prehospital airway management but remains associated with considerable procedural risk, particularly when multiple intubation attempts are required. First-pass success (FPS) is an established quality indicator because repeated attempts increase the risk of hypoxaemia, aspiration, oesophageal intubation, haemodynamic instability and cardiac arrest [1-4]. Although video laryngoscopy (VL) is recommended by international airway guidelines [5-8], evidence regarding the optimal blade geometry for prehospital airway management remains limited. We investigated the association between video laryngoscope blade geometry and FPS in a physician-staffed helicopter emergency medical service (HEMS).

methodsWe conducted a prospective bicentric observational study at two German physician-staffed HEMS bases between January 2017 and December 2019. Consecutive prehospital ETIs performed using the C-MAC

resultsA total of 283 video laryngoscopic intubations were analysed. Overall first-pass success (FPS) was 71.0% (201/283). Blade-specific FPS rates were 72.0% for Macintosh size 3, 72.6% for Macintosh size 4 and 61.9% for the hyper angulated D-Blade, without significant differences between blade geometries (p = 0.601). Adequate glottic visualisation (Cormack-Lehane grade I-II) was achieved in 96.8% of patients. Mean intubation duration was 42.5 ± 34.2 s. Airway-related adverse events occurred in 5.7% of patients and video laryngoscopy-associated technical problems in 12.6%. In an exploratory multivariable analysis, blade geometry was not independently associated with FPS, whereas difficult laryngoscopy conditions, poor glottic visualisation and technical problems were associated with failed first-pass intubation.

conclusionsVideo laryngoscopy provided excellent glottic visualisation irrespective of blade geometry. Neither univariable nor exploratory multivariable analyses demonstrated an independent association between blade geometry and first-pass success. Instead, difficult airway conditions, poor glottic visualisation and video laryngoscopy-associated technical problems appeared to exert a greater influence on procedural success. Given the observational design and limited number of hyper angulated blade intubations, these findings should be regarded as hypothesis-generating and require confirmation in larger prospective multicentre studies incorporating standardised difficult-airway assessment.