Correlation of intraoperative renal near infrared spectroscopy with the development of acute kidney injury in adult patients undergoing cardiac surgery using cardiopulmonary bypass

Introduction: The present study aimed to correlate renal oximetry near-infrared spectroscopy (NIRS) values with conventional non-invasive biomarkers for the early detection of acute kidney injury (AKI) in adult patients undergoing cardiac surgery using cardiopulmonary bypass (CPB). Accordingly, renal NIRS can be employed as a trending device for the prevention of AKI development. Materials and methods: After institutional ethical committee approval, a number of 132 adult patients undergoing cardiac surgery with CPB were selected by consecutive consenting sampling method. Emergency surgery and patients with preexistent renal insufficiency were excluded. NIRS sensor was applied on either the right or the left side of the spine at the lower border of L-1 before starting the induction. A renal regional oxygen saturation (rSO2) score was calculated after recording the renal oximetry values intra- and postoperatively. Urine output and serum creatinine were measured at 24, 48, and 72 hours postoperatively. Results: Out of 132 patients, 22 cases (16.66 %) developed AKI according to Acute Kidney Injury Network (Akin) criteria± Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) classification. Among these AKI patients, three cases required dialysis, and one of these three patients died on the 21st day postsurgery. Renal rSO2 scores in the AKI group were measured at 535 and 912 minutes %, in comparison to 162 and 184 minutes % reported in the non-AKI group which was statistically significant (P< 0.05). Conclusion: As evidenced by the obtained results, there is a correlation between intraoperatively measured renal NIRS readings and the occurrence of AKI following adult cardiac surgery using CPB.