Capillary refill time as a bedside perfusion indicator: associations with vital signs and triage acuity in the emergency department: a cross-sectional study

The capillary refill time (CRT) is the time it takes for a capillary bed to regain its color after being subjected to pressure. Capillary refill time (CRT) is a bedside perfusion indicator. We examined CRT across emergency department (ED) triage categories and identified independent correlates of CRT and prolonged CRT (> 2 s). In this cross-sectional study (July–September 2024), adults presenting to a tertiary ED were assigned green/yellow/red triage. CRT was measured in triplicate on the index-finger pulp after 10-s blanching and the mean was analyzed. Vital signs (SpO₂, heart rate, systolic/diastolic blood pressure, body temperature, skin temperature at the measurement site, and respiratory rate) were recorded. Associations were assessed using correlation and multivariable regression (overall and stratified by triage). We included 313 patients (mean age 55.8 ± 20.9 years; 53.4% female). CRT repeatability was high (ICC = 0.972, 95% Cl). Mean CRT was 2.00 ± 0.94 s and was longer in the red vs. other triage groups (2.36 ± 1.01 s; p < 0.001). In stratified models, green: heart rate (β > 0, p = 0.031) and respiratory rate (β < 0, p < 0.001); yellow: age (β > 0, p = 0.001) and respiratory rate (β > 0, p = 0.039); red: age (β > 0, p = 0.001) and respiratory rate (β > 0, p = 0.026). In the overall model, age and heart rate were positively, and systolic blood pressure negatively, associated with CRT (all p < 0.05). CRT varies with ED triage acuity and behaves as a rapid, reproducible bedside perfusion indicator. Age, heart rate, respiratory rate and systolic blood pressure are independent correlates of CRT, supporting its utility in initial assessment. Prospective, multicenter validation and prediction-model performance reporting (AUC, calibration) are warranted. The present study has been registered with the Clinical Trials Protocol Registration and Results System (ClinicalTrials.gov) under the registration number NCT07054151. The registration date is 26/06/2025.