Intraobserver and interobserver reliability of standardized capillary refill time in dogs is high following observer training.

Abstract

OBJECTIVE: To assess intraobserver and interobserver reliability of capillary refill time (CRT) measurement in dogs using a standardized technique after training. ANIMALS: 20 dogs presented to the emergency room. METHODS: Dogs presented to the emergency room were prospectively recruited. Using a timing device and standardized technique, CRT was measured at the oral mucosa of the inner lip. Measurements were performed by 2 emergency and critical care residents (observer 1 [Ob1] and observer 2 [Ob2]) and repeated 3 times by each observer for each dog. CRT values and signalment were recorded. Intraobserver and interobserver reliability were analyzed by calculation of the coefficient of variation (CV%), intraclass correlation coefficient (ICC), and minimal detectable difference. Reliability was considered high if CV% was lower than 10% and ICC was between 0.9 and 1. RESULTS: Median CRT for Ob1 was 1.22 seconds and for Ob2 was 1.19 seconds. Intraobserver reliability was high, evidenced by a median CV% of 6.2% (range, 1.0% to 18.6%) and 9.5% (range, 1.3% to 22.6%) and an ICC of 0.97 (95% CI, 0.94 to 0.99) and 0.95 (95% CI, 0.90 to 0.98) for Ob1 and Ob2, respectively. Between observers, the CV% was 4.4% (range, 0.8% to 17.5%) and the ICC was 0.98 (95% CI, 0.94 to 0.99), indicating high interobserver reliability. The minimal detectable differences for intraobserver and interobserver were 0.30 and 0.34 seconds, respectively. CLINICAL RELEVANCE: The reported high reliability of CRT despite its subjective nature enhances its usefulness in daily practice. However, further research on the validity of CRT is warranted.