The correlation between cardiopulmonary bypass time and lactate levels and the length of stay in intensive care unit in post-operative patients of coronary artery bypass grafting surgery

Link of Video Abstract: https://youtu.be/IyRnt5R0zR8 Background: Coronary artery bypass grafting surgery (CABG) is one surgical management for coronary artery disease (CAD). Hyperlactataemia in CABG is associated with poor postoperative outcomes. This study aimed to correlate cardiopulmonary bypass (CPB) time and serum lactate levels to the length of stay (LOS) in the intensive care unit (ICU) in patients with post-CABG. Methods: This was a cohort study of 358 patients with post-CABG from January 2016 until December 2021 in Dr. Kariadi Hospital Semarang, Indonesia. Subjects were selected by consecutive sampling. The correlation between CPB time and serum lactate levels, between CPB time and LOS in ICU, and between serum lactate levels and LOS in ICU were analyzed by non-parametric Spearman correlation test. Subjects were then divided into 2 groups, i.e. groups with lactate levels <4.0 mmol/L and≥4.0 mmol/L. The differences in LOS in the ICU were analyzed between both groups using the non-parametric Mann-Whitney test. Results: There was a correlation between CPB time and serum lactate levels in ICU (r=0.302, p=0.000), between serum lactate levels and LOS in ICU (r=0.194, p=0.003), and between CPB time and LOS in ICU (r=0.373, p=0.005). There was a longer CPB time in the group with lactate levels ≥4 mmol/L compared to that with lactate levels <4 mmol/L (70.7 ± 5.12 versus 66.9 ± 7.28, p=0.006). There was a longer LOS in ICU (3.8 ± 3.17 versus 3.1 ± 1.21, p=0.143) in a group with lactate levels ≥4 mmol/L compared to that with lactate levels <4 mmol/L, although it was not significant. Conclusion: There was a correlation between CPB time and LOS, and between serum lactate levels and LOS in ICU in patients after CABG. If confirmed by further findings, lactate levels might be a predictor for the outcome for patients after CABG including a longer LOS in ICU.