Establishment of a sedation threshold score for orthopedic radiographs in dogs and evaluation of inter-rater reliability and accuracy of video-based assessment

Background Sedation scales are commonly used to assess sedation levels in dogs, but no threshold scores exist to guide decisions on the need for additional sedatives.

Objective The objectives were to determine sedation score thresholds for obtaining orthopedic radiographs without restraint, evaluate inter-rater reliability, and compare video and real-time scoring.

Animals and procedure Dogs (N = 64) sedated for obtaining various orthopedic radiographs were scored using a validated sedation scale, both in real time (1 rater) and via video assessment (3 raters). Sedation threshold scores were determined using receiver operating characteristic curves and the Youden index based on a rater opinion (yes or no) of whether radiographs could be completed without restraint. Two thresholds were calculated: 1 for all radiograph types and 1 specifically for stifle radiographs. Discrimination between adequately and inadequately sedated dogs was evaluated via the area under the curve (AUC). Inter-rater reliability was assessed using the intraclass correlation coefficient, and agreement between scoring methods was analyzed using the Bland-Altman approach.

Results The threshold sedation scores were ≥ 16/21 (AUC = 0.71) for all radiographs and ≥ 12/21 (AUC = 0.77) for stifle radiographs, both indicating moderate ability to distinguish between adequately and inadequately sedated dogs. The inter-rater reliability of combined scores was very good (intraclass correlation coefficient > 0.81) for all raters, and the mean bias between video and real-time scoring was -0.08.

Conclusion and clinical relevance The determined threshold scores can assist clinicians in determining whether additional sedation is necessary. The sedation scale demonstrated high reliability and accuracy, particularly when scored via video.