Diagnostic value of the percentage of glottic opening score for classifying videolaryngoscopy in children: a prospective validation study

INTRODUCTION: The percentage of glottic opening (POGO) score quantifies the laryngeal view obtained during laryngoscopy. This secondary analysis of the prospective observational PeDiAC study aimed to compare the POGO score with subjective glottic view ratings on a visual analogue scale (VAS) for classifying difficult videolaryngoscopic tracheal intubation. METHODS: Videolaryngoscopy was used as the first-line approach for tracheal intubation in children over a study period of 16 months. Immediately after tracheal intubation, the airway operators documented a VAS rating of 0-100, with higher values indicating better glottic views. Using videolaryngoscopy recordings of airway management, POGO scores were assigned in a post-hoc analysis. RESULTS: The study comprised 904 tracheal intubations in 809 children. Difficult videolaryngoscopic tracheal intubation occurred in 47 (5.2%) cases. The POGO score had poorer diagnostic performance than VAS rating for classifying difficult videolaryngoscopic tracheal intubation, with AUROCs of 0.52 95%CI (0.42-0.62) and 0.79 (95%CI 0.73-0.86), respectively, p < 0.001. Based on the AUROC, the POGO score had a poorer diagnostic performance than VAS rating for predicting multiple laryngoscopy attempts (0.46 (95%CI 0.40-0.51) vs. 0.66 (95%CI 0.61-0.71), p < 0.001); multiple tracheal intubation attempts (0.45 (95%CI 0.41-0.50) vs. 0.64 (95%CI 0.60-0.68), p < 0.001); time to tracheal intubation > 90 s (0.45 (95%CI 0.40-0.51) vs. 0.70 (95%CI 0.65-0.75), p < 0.001); airway-related adverse events (0.51 (95%CI 0.41-0.61) vs. 0.65 (95%CI 0.57-0.74), p = 0.030); and severe hypoxaemia (0.47 (95%CI 0.35-0.59) vs. 0.63 (95%CI 0.52-0.73), p = 0.047). A POGO score < 50% had low positive predictive value of 0.11 (95%CI 0.04-0.22) and sensitivity of 0.13 (95%CI 0.05-0.27) for the occurrence of a difficult videolaryngoscopic intubation and the POGO score showed limited inter-rater reliability (intraclass correlation coefficient 0.61 (95%CI 0.47-0.72)). DISCUSSION: The POGO score has poor diagnostic performance for classifying difficult videolaryngoscopic tracheal intubation and low inter-rater reliability in children.