Effect of lactate levels on extubation time in coronary artery bypass grafting surgery

In current practice, fast-track protocols are gaining importance in patients undergoing cardiac surgery. For this purpose, besides different application techniques, biomarkers are frequently examined in the peri-operative period. We aimed to examine whether serum lactate levels at different peri-operative intervals had an effect on the extubation time.

The patients were analysed in two groups according to the extubation time (early < 6 hours, and late extubation > 6 hours). Individual characteristics, co-existing diseases, blood transfusion, inotropic support, intra-aortic balloon pump, cardiopulmonary bypass time, aortic cross-clamp time, and the serial measurements of serum lactate levels were recorded. Correlations of serial measurements of lactate levels and the peri-operative variables with extubation times were analysed.

No significant differences were observed between the groups in terms of co-existing diseases and individual characteristics. However, cardiopulmonary bypass, aortic cross-clamp times and all lactate levels after aortic cross-clamping were found to be significantly different (p = 0.001). A statistically significant correlation was found between the cut-off value of 1.7 for serum lactate levels after aortic-cross clamping (L2); 1.9 for levels after aortic cross-clamp removal (L3); 2.2 for levels after cardiopumonary bypass (L4); 2.1 for levels after intensive care admission (L5); 1.7 for levels after first postoperative hour in the intensive care unit (L6), and 1.8 for the difference between pre-operative levels (L0) and the peak level of lactate in the peri-operative period (ΔL) in predicting extubation time (p < 0.01).

We concluded that cardiopulmonary bypass and aortic cross-clamp times, and intra-operative serum lactate levels were important in predicting early extubation after isolated coronary artery bypass graft surgery.