Microvascular Reactivity in Cardiac Surgery

Microcirculatory disturbance occurs most seriously during cardiopulmonary bypass (CPB) in cardiac surgery. If microvascular reactivity compensates for microcirculatory disturbance during CPB, tissue hypoxemia may be minimized. On the other hand, tissue hypoxemia may develop and lead to poor clinical outcomes. The primary aim of this study was to assess whether microvascular reactivity during CPB can predict major adverse events (MAE) within 30 days after cardiac surgery. This prospective, observational, single-center study was conducted on 115 patients who underwent elective on-pump cardiac surgery. The vascular occlusion test (VOT) with near-infrared spectroscopy was performed five times for each patient, before the induction of general anesthesia (baseline, T0), 30 min after the induction of general anesthesia (T1), 30 min after applying CPB (T2), 10 min after injection of protamine (T3), and after sternal closure (T4). Sequential Organ Failure Assessment (SOFA) and Acute Physiologic and Chronic Health Evaluation (APACHE) II scores and the length of ventilator care, intensive care unit stay, and hospital stay were recorded. Postoperative MAE within 30 days after surgery was also recorded.