Capillary refill time exploration during septic shock

During septic shock management, the evaluation of microvascular perfusion by skin analysis is of interest. We aimed to study the skin capillary refill time (CRT) in a selected septic shock population.

We conducted a prospective observational study in a tertiary teaching hospital. After a preliminary study to calculate CRT reproducibility, all consecutive patients with septic shock during a 10-month period were included. After initial resuscitation at 6 h (H6), we recorded hemodynamic parameters and analyzed their predictive value on 14-day mortality. CRT was measured on the index finger tip and on the knee area.

CRT was highly reproducible with an excellent inter-rater concordance calculated at 80% [73-86] for index CRT and 95% [93-98] for knee CRT. A total of 59 patients were included, SOFA score was 10 [7-14], SAPS II was 61 [50-78] and 14-day mortality rate was 36%. CRT measured at both sites was significantly higher in non-survivors compared to survivors (respectively 5.6 ± 3.5 vs 2.3 ± 1.8 s, P < 0.0001 for index CRT and 7.6 ± 4.6 vs 2.9 ± 1.7 s, P < 0.0001 for knee CRT). The CRT at H6 was strongly predictive of 14-day mortality as the area under the curve was 84% [75-94] for the index measurement and was 90% [83-98] for the knee area. A threshold of index CRT at 2.4 s predicted 14-day outcome with a sensitivity of 82% (95% CI [60-95]) and a specificity of 73% (95% CI [56-86]). A threshold of knee CRT at 4.9 s predicted 14-day outcome with a sensitivity of 82% (95% CI [60-95]) and a specificity of 84% (95% CI [68-94]). CRT was significantly related to tissue perfusion parameters such as arterial lactate level and SOFA score. Finally, CRT changes during shock resuscitation were significantly associated with prognosis.

CRT is a clinical reproducible parameter when measured on the index finger tip or the knee area. After initial resuscitation of septic shock, CRT is a strong predictive factor of 14-day mortality.