Hyperlactatemia after Cardiac Surgery as a Prognostic Risk Factor

Background Elevated blood lactate level after cardiac surgery is an indicator of systemic hypoperfusion and tissue hypoxia. Our aim of the study was to evaluate the relationship between postoperative blood lactate levels and outcome in patients undergoing open heart surgery and to verify the clinical impact of hyperlactatemia (HL) and low lactemia (LL) after coronary artery bypass grafting in terms of postoperative morbidity and mortality rate. Methods Postoperative blood lactate level was measured in 96 patients. Low and high lactate level was defined as level less than or equal to 4 mmol/L in 69 (Group A) and more than 4 mmol/L in 27 patients (Group B) respectively. Preoperative, perioperative and postoperative details were retrieved from patient records. Results Demographic characteristics, postoperative data were similar in both groups. Increased cross-clamp and cardiopulmonary bypass times in patients who underwent on pump were associated with a significant rise in postoperative lactate levels. Increased length of ICU stay (Group A 78.49 41.96 vs. Group B 91.81 59.44), mechanical ventilation time (Group A 9.47 6.17 vs. Group B 15.07 14.15) and higher mortality rates (Group A no=01 vs. Group B no=4) were also found in high lactate group. Conclusion Longer duration of CPB and cross clamp time are associated with a significant increase in lactate levels during perioperative period and that increased lactate levels are directly associated with the increased duration of mechanical ventilation, postoperative ICU stay and mortality.