Utility Of Serum Lactate and Base Deficit as Predictors of Early Outcomes Aftercardiopulmonary Bypass

Abstract

Background: Cardiopulmonary bypass (CPB) is associated with complex physiological changes, including altered oxygen delivery, systemic inflammatory response, and metabolic disturbances that may contribute to postoperative morbidity. Serum lactate and base deficit are easily measurable indicators of tissue hypoperfusion and metabolic stress; however, their combined predictive utility for early outcomes after CPB requires further evaluation. This study aimed to assess the role of serum lactate and base deficit as predictors of early postoperative complications following CPB-assisted cardiac surgery. Methods: Serial arterial blood gas analyses were performed at predefined perioperative time points, including before CPB, during CPB, at termination of CPB, ICU admission, and 6 hours postoperatively. Serum lactate levels and base deficit values were recorded. Patients were followed during the early postoperative period for major complications, including acute kidney injury, prolonged mechanical ventilation, low cardiac output syndrome, arrhythmias, prolonged ICU stay, and in-hospital mortality. The predictive performance of lactate and base deficit was evaluated using receiver operating characteristic (ROC) curve analysis. Results: The mean age of study participants was 58.4 ± 10.6 years, with male predominance (67.8%). Serum lactate levels increased progressively from baseline (1.2 ± 0.4 mmol/L) to peak values at ICU admission (3.6 ± 1.5 mmol/L) before declining during early postoperative recovery. Early postoperative complications occurred in 32 patients (35.6%). Conclusion: Serum lactate and base deficit are effective early predictors of adverse postoperative outcomes following cardiopulmonary bypass-assisted cardiac surgery.