The Influence of mean arterial blood pressure during CPB on the rate of postoperative acute kidney injury in elderly diabetic patients after CABG surgery

Abstract

Objective: Acute kidney injury (AKI) is a common and serious complication of cardiac surgery. Elderly patients with diabetes mellitus represent a population that is at additional risk. The aim of study was to investigate the influence of mean arterial blood pressure (MABP) during cardiopulmonary bypass (CPB) on the rate of postoperative AKI in elderly diabetic patients and to find out if relatively low MABP may impair renal function. Methods: 60 CABG patients aged 70 years and elder with diabetes mellitus and normal preoperative renal function were randomly divided into two groups: in group I MABP was maintained lower then 60 mmHg (n=26), in group II MABP was 63 mmHg and higher (n=34). Patients’ clinical data were evaluated during 48 hours after the surgery. Results: In the group I MABP was 50.6-58.9 mmHg in the II group – 63.7-93.6 mmHg. Serum creatinine concentration did not differ between groups (124.2±25.11 μmol/l vs. 127.7±50.66 μmol/l respectively, p=0.9024). The mean urine output was slightly lower in group I during the first postoperative day (1439±388 ml vs. 1931±592 ml, p=0.0412) but there were no significant differences between the groups during the second postoperative day (2347±933 ml vs. 2251±795 ml, p=0.8521). The volume balance, serum potassium level and the need for diuretics did not differ between the groups. There were not any cases of AKI during the study period. Conclusion: MABP of 50–60 mmHg during CPB is save enough and is not related to postoperative renal dysfunction in elderly diabetic patients after CABG surgery.