Comparison of the effects of PVC and silicone coated lines in cardiopulmonary bypass on lactate levels in the postoperative period

Cardiopulmonary bypass (CPB) surgery, blood contact with foreign surfaces, and disruption of hemodynamic balance can lead to metabolic stress and an inflammatory response. The materials used in heart-lung machines (PVC or silicone) can have different effects on blood component damage, biocompatibility, and gas exchange. These differences, particularly their effects on lactate levels, a key biochemical marker of tissue perfusion, are considered prognostic indicators for morbidity and mortality due to factors such as hyperlactatemia, tissue hypoxia, and anaerobic metabolism that develop during and after CPB. This study aims to compare the effects of PVC and silicone tube head lines on postoperative lactate levels. All blood gas parameters, cross time, pump time, and temperature were retrospectively analyzed in 200 patients aged 18-75 who underwent elective cardiovascular surgery with an S5 model heart-lung machine at Gaziantep Şahinbey Training and Research Hospital between December 2023 and December 2024. The patients were divided into two groups as PVC (n=100) and silicone (n=100) according to the type of line used in the cylinder pump head of the heart-lung machine. Pre- and postoperative hematocrit (HCT) and lactate values were recorded. Statistical analysis was performed using SPSS 23 program; parametric and nonparametric tests were used for inter-group comparisons, and dependent samples t-test was used for within-group analyses. The level of significance was accepted as p<0.05. As a result of these findings, preoperative hemoglobin, hematocrit, and lactate levels were similar between the two groups (p>0.05). Postoperatively, significant differences were found in HCT and lactate values based on the line material (p<0.05). Postoperative HCT was higher in patients using silicone lines, and lactate levels were lower than in the PVC group. Consequently, a significant increase in postoperative lactate levels was observed in the PVC line, but not in the silicone line group. These findings suggest that silicone lines may offer advantages in terms of biocompatibility and metabolic stability lower rates of microembolism and hemolysis and contribute to the maintenance of tissue perfusion in the postoperative period.