Background Capillary refill time (CRT) has been advocated as a tool for rapid assessment of circulatory status. The correlation between neither CRT and mortality nor CRT and markers of circulatory status has been assessed. We performed a prospective observational cohort study to assess the relationship between CRT (using two existing definitions and as a continuous variable) and short-term mortality.

Methods We included all acutely admitted adult patients to a medical admission unit. We measured CRT, blood pressure, pulse, temperature and peripheral oxygen saturation. We presented the data descriptively. Difference between continuous data was analysed using Wilcoxon Rank Sum Test and categorical data using χ² test. The primary endpoint was 1-day all-cause mortality.

Results 3046 patients were enrolled and CRT was measured on 1935. In univariate analyses, we found increasing all-cause 1-day mortality with all definitions of CRT. Performing multivariable analysis, controlling for age, sex, mean blood pressure, pulse, temperature and peripheral oxygen saturation, we found increasing CRT as a continuous variable and according to the Schriger and Baraff definition to be associated with increased mortality. Both the Trauma score and Schriger and Baraff definitions had high negative predictive values. The calculations on the Schriger and Baraff defition were based on limited power.

Conclusions We found a significant association between CRT measured as a continuous variable and short-term mortality. Using the definition of Schriger and Baraff also seems appropriate, but this is based on calculations of limited power.