Abstract
Background/Objectives: In critically ill patients, achieving a mean arterial pressure (MAP) of 65 mmHg is a recommended resuscitation goal to ensure proper tissue oxygenation. Unfortunately, some patients do not benefit from providing such a value, suggesting that other indices are needed for better hemodynamic assessment. Capillary refill time (CRT) has emerged as an established marker for peripheral perfusion and a therapeutic target in critical illness, but its relationship with other exponents of hypoperfusion during vasopressor support after resuscitation period still warrants further research. This study aimed to investigate whether in critically ill patients after initial resuscitation, CRT would provide information independent of other, readily accessible hemodynamic variables. Methods: Critically ill patients who were mechanically ventilated after the resuscitation period and receiving vasopressors were prospectively studied between December 2022 and June 2023. Vasopressor support was measured using norepinephrine equivalent doses (NEDs). CRT, MAP and NED were assessed simultaneously and analyzed using Spearman's rank correlation. Results: A total of 92 patients were included and 210 combined MAP-CRT-NED-Lactate records were obtained. There was no correlation between CRT and MAP (R = -0.1, p = 0.14) or lactate (R = 0.11, p = 0.13), but there was a positive weak correlation between CRT and NED (R = 0.25, p = 0.0005). In patients with hypotension, in 83% of cases (15/18), CRT was within normal range, despite different doses of catecholamines. When assessing patients with high catecholamine doses, in 58% cases (11/19), CRT was normal and MAP was usually above 65 mmHg. Conclusions: Capillary refill time provides additional hemodynamic information that is not highly related with the values of mean arterial pressure, lactate level and vasopressor doses. It could be incorporated into routine physical examination in critically ill patients who are beyond initial resuscitation.