Oxygen Delivery During Cardiopulmonary Bypass as a Determinant of Acute Kidney Injury Following the Cardiac Surgery

INTRODUCTION: Acute Kidney Injury (AKI) is one of the severe complications that develop following cardiac surgery. Incidence of AKI following cardiac surgery has been found to be in the range 8.9% to 42.5%(1). Various factors have been implicated as possible determinants of AKI. Among them, delivery of oxygen (DO2I) level < 280 mL/minute/m2 during CPB was independently associated with AKI(2). Cutoff value of low DO(2)I is based on western literatures and there is a paucity of literature available on same subject among the Indian patients. OBJECTIVE: Primary objective is to determine the cutoff value of DO(2) value during CPB that is associated with postoperative AKI and secondary outcome is to find out the other risk factors associated with AKI. MATERIALS AND METHODS: Prospective observational study conducted a tertiary health care setting from March 2023 to Dec 2023. Sample size estimation is based on incidence of AKI following cardiac surgeries in the previous study(2). Patient were induced with anesthesia as per protocol and treated with moderately hypothermic CPB. Patient demographic data, preoperative lab parameters, intraoperative hemodynamic parameters, CPB parameters, DO(2) levels during CPB, postoperative serum creatinine was collected. Mean values were compared using Independent sample t-test (2 groups). Categorical outcomes were compared using Chi square test. The Lowest DO2I in predicting AKI was assessed by Receiver Operative curve (ROC) analysis. P value < 0.05 was considered statistically significant. RESULTS: 200 enrolled for the study. 147 patients were male (73.50 %) and the mean age was 59.17 ± 9.66. 45 out of 200 (22.5%) patients developed AKI. Rates of Diabetes, hypertension, smoking, alcoholism and EuroSCORE II were significantly higher in patients with AKI. AKI patients underwent longer CPB and cross-clamp periods, needed more red blood cell transfusions, and showed lower DO2i values throughout the procedure. Cut off value of DO2I which is associated with development of AKI was found to be 262.2 ml/min/m2. DISCUSSION: Our study showed that incidence of AKI is 22.5 % which is similar to study conducted by Elena Carrasco-Serrano et al(1). Patients who are diabetic, hypertensive, alcoholics, smokers and those having higher EuroSCORE had higher chances of developing AKI which is similar to study conducted by Carrasco-Serrano et al and de somer at al.(1, 2) Our study showed that DO2I of 263.5 ml/min/m2 is associated with higher chances of developing acute kidney failure which is similar to study conducted by de somer et al(2). CONCLUSION: Low DO2I during cardiopulmonary bypass is a associated with development of AKI and Cutoff value of DO2I identified by our study was 263.5 ml/min/m2.