Background: Acute kidney injury (AKI) is a severe complication that can occur after open heart surgery and known to exacerbate prognosis. However, patient management during a cardiopulmonary bypass (CPB) procedure to prevent AKI has not been established. Here, we retrospectively investigated AKI in patients who underwent cardiac surgery with CPB.
Patients and Methods: We conducted a retrospective analysis of 371 patients who underwent open heart surgery with CPB from 2012 to 2015 at the Sakakibara Heart Institute of Okayama, Japan. For cases with a CPB time of 120 minutes or longer and a minimum bladder temperature of 32˚C or more, AKI was defined according to the Acute Kidney Injury Network (AKIN) classification criteria. 10)
Results: AKI developed in 59 patients (15.9% ). In the AKI group, the rate of introduction of continuous renal replacement therapy was significantly higher, and they also had significantly longer ICU and postoperative hospital stay durations. Multivariable analysis showed that body weight greater than 66.1kg, preoperative estimated glomerular filtration rate lower than 56.9mL/min/1.73m2, administration of red blood cells greater than 6 IU, lowest oxygen delivery (DO2) during CPB less than 259mL/min/m2, and amount of urine output during CPB less than 2.8mL/kg/h were significantly associated with AKI development after CPB.
Conclusion: Our results indicate that DO2 greater than 259mL/min/m2 during CPB and monitoring urine output amount (>2.8mL/kg/h) during CPB are independent factors related to a decrease in risk of AKI in cardiac surgery patients.