The Effect of Serum Lactate and Lactate Clearence on Mortality in Cardiac Surgery Patients

Objective: Lactate levels may increase due to tissue hypoperfusion that may occur during cardiopulmonary bypass. The blood lactate level is a dynamic variable, so a single lactate measurement may not always give sufficient information about the patient. Our aim was to evaluate whether a dynamic parameter such as lactate clearance was more useful in predicting mortality and morbidity after cardiac surgery. Material and Methods: A total of 591 patients who underwent cardiovascular surgery between January 2010-September 2018 were respectively included in the study. Among patients; hemodynamic parameters, extubation durations, duration of intensive care unit stay, total duration, of hospital stay and death time of those who died within 28 days were recorded. The patients were classified into two groups:The highest lactate level <4 (Group 1) and ≥ 4 (Group 2). Among the groups; hospital and intensive care stay periods and mortality ratios were compared. 24-hour and 72-hour lactate clearances were measured in all patients. Results: Cross clamp duration (86.5±78 vs. 74.4±26.9, p=0.005) and cardiopulmonary bypass duration (122.6±38.3 vs. 112.5±36.8, p=0.002) were significantly longer in Group 2. Lactate clearance level (T1-2) at 24th hour was significantly lower in patients who do not survive compared to the patients who survive [-12.33±81.47 vs 12.56±68.94, p=0.009]. Correlation analysis revealed a weak and positive correlation between 24th hour lactate clearance and duration of hospital stay. Conclusion: The addition of dynamic lactate parameters to the evaluation, such as lactate clearance, may be useful in predicting morbidity and mortality after cardiac surgery.