The effect of values of hematocrit and oxygene delivery during cardiopulmonary bypass on renal function in patients with Diabetes mellitus

Aim of the study: In this prospective clinical study; we aimed to investigate the effects of different values of hematocrit (hct) and oxygene delivery (DO2) during cardiopulmonary bypass (CPB) on early postoperative renal function in patients with diabetes mellitus (DM).Material and Methods: After Ethics Committee approval, 40 diabetic patients undergoing coronary artery bypass grafting (CABG) surgery were assigned into Group 1 (Hct<%23, n:20) and Group 2 (Hct ?23, n:20) according to their hematocrit (Hct) values during CPB. Pulsatile pump flow was set as 2.4±0.4 L/min/m2 and the values of DO2 (mL/dk/m2) were determined. Values of blood urea nitrogen (BUN, mg/dL), serum creatinine (Scr, mg/dL) and creatinine clearence (Ccr, mL/dk) were determined at the preoperative period (Pre), postoperative 1st hour (P1) and postoperative 24th hour (P24). Chi-square, Mann-Whitney U, Friedman variance analysis, Wilcoxon signed-ranks tests were used for statistical analysis. Values were given as mean±SD and p<0.05 was considered significant.Results: Demographics and clinical characteristics of patients did not differ between groups (p>0.05). The values of Hct (lowest; 20.4 ±1.6%, highest; 22.1±1.6) and DO2 (lowest; 228 ± 25, highest; 261 ± 29) in Group 1 were significantly lower than the values of Hct (lowest; 25.1±1.8%, highest; 25.6±2.2) and DO2 (lowest; 282±20, highest; 297±22) in Group 2 at the 20th, 40th, 60th and 80th minutes of CBP (p<0.05, p<0.05, respectively). BUN was found as 16±6, 15±4, 20±8, Scr was found as 0.9±0.2, 1.0±0.2, 1.2±0.3, and Ccr was found as 76±22, 74±21, 62±21 at Pre, P1 and P24 in group 1 (respectively). In group2; BUN was found as 18±5, 16±5, 19±5, Scr was found as 0.9±0.9, 0.9±0.2, 1.0±0.3, and Ccr was found as 85±26, 78±20, 72±25 at Pre, P1 and P24 in group 2 (respectively). No significant differences were found in BUN (p>0.05), Scr (p>0.05) and Ccr (p>0.05) at Pre, P1 ve P24 between the groups. Significant differences were found in BUN (compared to Pre), Scr ve Ccr (compared to Pre and P1) in group 1 and in BUN (compared to P1), Scr and Ccr (compared to Pre) in group 2 at P24 (p<0.05, p<0.05, respectively).Conclusion: In this clinical study, we observed that different levels of Hct which was below %23 or equal and above %23, and different values of DO2 which depended on hct did not cause any different effects on renal function in patients with DM at the early postoperative period.Keywords: Coronary artery bypass grafting surgery, cardiopulmonary bypass, diabetes mellitus, hematocrit, oxygene delivery, renal function.