The Influence of Biocompatibility of the Extracorporeal Oxygenator Circuit on the Degree of Hemolysis and Optimization of Oxygen Status in Minimally Invasive Coronary Artery Bypass Grafting

Introduction. A distinctive feature of cardiopulmonary bypass in minimally invasive coronary artery bypass grafting (CABG) is the significantly longer perfusion time, involving active blood drainage from the vein to the cardiotomy reservoir, which carries the risk of hemolysis development. In this context, mechanical hemolysis disrupts the gas transport function of the blood. The aim of the research. Reducing hemolysis and optimizing oxygen status of patients during minimally invasive coronary artery bypass grafting surgeries. Materials and methods. The study included 60 patients, who underwent minimally invasive coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) under moderate hypothermia. The patients were divided into two groups of 30 individuals each. To improve the biocompatibility of the oxygenator, the circuit in Group 1 (Gr1) was treated with an adaptive composition, while in Group 2 (Gr2), the oxygenator circuit remained untreated. The following parameters were examined: hemoglobin (Hb), hematocrit (Ht), red blood cell count (RBC), oxygen delivery index (DO2I), oxygen consumption index (VO2I), oxygen extraction ratio (O2ER%), oxygen extraction index (O2EI%), venous (SpvO2), and arterial (SpaO2) oxygen saturation, oxygen tension in arterial (PaO2) and venous blood (PvO2), acid-base status of the blood (pH, pCO2,HCO3ˉ, BE), and the degree of hemolysis. Results. Before initiation of cardiopulmonary bypass (CPB), an insignificant increase in O2IE% was observed in Gr1 (26.07±1.57) and Gr2 (27.11±0.81); p=0.875, indicating an increase in tissue oxygen consumption. At the hypothermic stage CPB, both Gr1 and Gr2 demonstrated a statistically significant decrease in Hb, Ht, and RBC levels (p<0.05) due to hemodilution, accompanied by a decrease in IDO2, IVO2, O2IE%, and O2ER% in both groups due to hypothermia. After rewarming, O2ER% in Gr1 (22.91±2.68) and Gr2 (24.59±2.02); p=0.191, and O2EI% in Gr1 (22.92±2.44) and Gr2 (24.61±2.01); p=0.215, were in the normal range. After weaning off cardiopulmonary bypassin Gr2, O2EI% was 27.34±1.97, indicating an increase in oxygen consumption and oxygen extraction. Upon separation from CPB, Gr2 showed a tendency to mild compensated metabolic acidosis, mainly due to HCO3ˉ 21.9±0.3. During the rewarming stage, the hemolysis value was 0.36±0.09in Gr1 and 0.45±0.17 in Gr2 (p<0.001). After CPB, hemolysis was 0.41±0.15 in Gr1 and 0.61±0.22 in Gr2 (p<0.001). Conclusions. Improving the biocompatibility of the extracorporeal oxygenatorcircuit makes it possible to reduce hemolysis and optimise the patient's oxygen status after cardiopulmonary bypass in minimally invasive coronary artery bypass grafting.