Risk factors of acute renal injury after major elective NON-cardiac surgery : A prospective observational study

OBJECTIVE: In this prospective observational study, we aimed to determine the incidence of acute renal injury after elective major abdominal surgery in our hospital and its related risk factors. MATERIALS AND METHODS: After the approval of the ethics committee and consent of the patients, patients who underwent major elective abdominal surgery, aged 18 and over, between ASA I-III, who had undergone major elective abdominal surgery between June 2019 and November 2020 were included in the study. The patients were divided into Group AKI+ and Group AKI–. Patients' demographic data, preoperative status and laboratory data, operation-related data, and postoperative laboratory and follow-up data were noted. The patients were followed up for complications and mortality within three months after the operation date. RESULTS: In 425 patients included in the statistical analysis, the incidence of AKI after elective major abdominal surgery in our hospital was found to be 12% (49/425). Preoperative age, ASA class, functional capacity were higher in group AKI+ patients, and presence of hypertension, DM, chronic renal failure, use of beta blockers, presence of ascites in the abdomen, and presence of anemia were found more frequently. On the other hand, smoking was more common in patients who did not develop AKI. In the intraoperative period, the use of colloids, blood products, and vasopressors were recorded more frequently in patients with AKI, and the amount of intraoperative bleeding was higher. The lowest mean arterial pressure observed intraoperatively below 60 or 50 mmHg was found more frequently in patients who developed AKI. In the postoperative period, the need for intensive care follow-up, blood product, vasopressor and diuretic use were found more frequently in patients who developed AKI. In the multivariate analysis, postoperative vasopressor use, the lowest intraoperative mean arterial pressure below 50 mmHg, intraoperative colloid use, and high body mass index were found to be independent risk factors, in order of importance in increasing risk (respectively OR=5,1, %95CI 1,352-18,904, p=0,016; OR=3,9, %95CI 1,319-11,555, p=0,014; OR=2,74, %95CI 1,111-6,757, p=0,029; OR=1,15, %95CI 1,069-1,239, p<0,001). It was observed that the duration of intensive care and hospitalization was longer in patients with AKI, while the frequency of complications and reoperation was higher. 30- and 90-day mortality was found more frequently in patients who developed AKI. CONCLUSIONS: In this study, it was found that the use of postoperative vasopressors, the lowest intraoperative mean arterial pressure below 50 mmHg, the use of intraoperative colloid and a high body mass index were independent risk factors for the development of postoperative AKI. It was observed that the development of postoperative AKI was associated with increased complications, length of stay in hospital and intensive care unit, cost and mortality. Therefore, in order to reduce the incidence of postoperative AKI, triggering agents should be avoided in patients with risk factors, and hypotension and colloid use should be avoided in all patients.