DiCART^TM device to measure capillary refill time: a validation study in patients with acute circulatory failure

Capillary Refill Time (CRT) is a valuable metric to assess cutaneous perfusion. Its prognostic value in patients with acute circulatory failure has been reported as improved when the measurement is standardized. The DiCART™ device is a fully automated CRT measurement tool requiring validation. We conducted a comparative interventional single-center study including 25 patients with acute circulatory failure, to evaluate the agreement between CRT measured by an automated measurement device (CRT_DiCART) and CRT measured clinically (CRT_CLIN). CRT was measured on the fingertip, chest, and knee. Three measurements were performed at each location to obtain an average for each site. The measurements were conducted both clinically and using the DiCART™ device by two different operators, each blinded to the results. Agreement was determined using intraclass correlation coefficient (ICC) and Bland and Altman analysis. The ICC between CRT_CLIN and CRT_DiCART was 0.46 (95% Confidence Interval (CI) 0.32, 0.59) across all measurement sites; the mean bias was 0.23s (95% CI -0.17, 0.64), with upper Limit of Agreement (LoA) 2.77s (95% CI 2.44, 3.20) and lower LoA - 2.30s (-2.73, -1.97). Intra observer ICC was 0.85 (95% CI 0.74, 0.91) for CRT_CLIN and 0.43 (95% CI 0.15, 0.64) for CRT_DICART. Inter observer ICC was 0.86 (95% CI 0.76, 0.92) for CRT_CLIN and was 0.41 (95% CI 0.14, 0,63) for CRT_DICART. The DiCART™ device showed poor agreement with clinical CRT in patients with acute circulatory failure, which does not support its use in routine practice.