Hyperlactatemia in patients undergoing pulmonary endarterectomy with deep hypothermic circulatory arrest: Risk factors and its effects on the outcome

Introduction: To determine the risk factors of hyperlactatemia in pulmonary endarterectomy (PEA) surgery and assess whether elevated blood lactate levels are associated with adverse outcomes.Methods: In this retrospective observational study, a total of 111 consecutive patients who underwent PEA for chronic thromboembolic pulmonary hypertension at the XXX Hospital between December 2016 and January 2022 were included. We retrospectively evaluated arterial blood samples analyzed intraoperatively. The pre- and intraoperative risk factors for hyperlactatemia and the postoperative outcomes were recorded.Results: Lactate levels gradually increased during surgery. The optimal cut-off lactate level for major postoperative complications, calculated using receiver operating characteristic analysis, was 7.0 mmol/L. Deep hypothermic circulatory arrest (DHCA) duration, nadir hematocrit, and preoperative pulmonary vascular resistance were risk factors for lactate levels >7 mmol/L. Moreover, the intraoperative peak lactate level during PEA under DHCA was found to be a statistically significant predictor of major complications being associated with longer mechanical ventilation time (r = 0.294; p = .003) and intensive care unit length of stay (r = 0.327; p = .001).Conclusions: Deep hypothermic circulatory arrest duration, nadir hematocrit, and preoperative pulmonary vascular resistance were associated with hyperlactatemia. Increased lactate levels were independent predictors of longer mechanical ventilation time, intensive care unit length of stay, and major complications.