Microvascular reactivity measured by vascular occlusion test is an independent predictor for postoperative bleeding in patients undergoing cardiac surgery

The purpose of the study is to investigate the relationship between microvascular reactivity and postoperative bleeding in cardiac surgery. The authors retrospectively analyzed a prospectively collected registry of cardiac surgery patients. Data from 154 patients enrolled in the registry were analyzed. A linear mixed model was performed to evaluate the association between the amount of postoperative chest tube output (CTO, milliliter, repeatedly measured at 0–8, 8–24, and 24–48 h) and tissue oxygen saturation (StO₂₎ recovery slope (%/s) measured by vascular occlusion test (VOT) at skin closure. A logistic regression was carried out to see the relationship between StO₂ recovery slope and packed red blood cell (PRBC) transfusion during the 48-h postoperative period. In the multivariable adjusted model, the effect of StO₂ recovery slope on postoperative CTO (log-transformed) was statistically significant, and the degree of StO₂ recovery slope was inversely related to the amount of CTO (exp(estimate) = 0.935; exp(95% CI) 0.881–0.992; p = 0.027). StO₂ recovery slope was also inversely associated with postoperative PRBC transfusion possibility (OR = 0.795; 95% CI 0.633–0.998; p = 0.048). Microvascular reactivity measured by VOT is independently and inversely associated with postoperative bleeding in patients undergoing cardiac surgery.