Evaluation of Laryngeal View and Video-Based Percentage of Glottic Opening Scoring in Dogs Using a Video Laryngoscope

Direct laryngoscopy provides a transient view of the canine larynx that is difficult to document or review. We compared direct and monitor laryngeal views obtained using a video laryngoscope and evaluated the reproducibility of video-based percentage of glottic opening (POGO) scoring in clinical dogs. In a prospective study, an operator assessed modified Cormack–Lehane (C–L) grades by direct line of sight and on the monitor, without repositioning the blade, in 20 dogs. Three blinded raters independently selected optimal frames and scored recorded videos from 19 dogs. Monitor visualization improved C–L grade in eight dogs, was unchanged in 11, and worsened in one (p = 0.03). POGO scoring showed excellent inter-rater reliability (single-measure intraclass correlation coefficient [ICC] = 0.94; average-measure ICC = 0.98), which remained good after excluding dogs with uniform scores of 0% or 100% (single-measure ICC = 0.83), and was strongly associated with monitor C–L grade (Spearman’s ρ = −0.91). Video laryngoscopy facilitates reviewable, quantitative documentation of canine laryngeal views; whether it improves intubation performance requires further study with standardized monitor use.