[Acute kidney injury early after cardiac surgery with cardiopulmonary bypass: clinical analysis].

Objective: To explore the occurrence of acute kidney injury (AKI) in early stage after cardiac surgery under cardiopulmonary bypass (CPB) and discuss the perioperative risk factors and its impact on clinical outcome.

Methods: Retrospective analysis was performed among 1472 adult patients undergoing cardiac surgery with CPB between January 2008 and April 2011. The postoperative occurrence of AKI following cardiac surgery was stratified according to the RIFLE criteria. And the perioperative risk factors of AKI and its impact on clinical outcome were analyzed.

Results: AKI occurred in 437 patients (29.7%) within 72 hours postoperation. Of these, 292 (19.8%) fulfilled AKI-Risk, 110 (7.5%) AKI-Injury and 35 (2.4%) AKI-Failure. Logistic regression analysis showed that age, hypertension, chronic renal insufficiency, reoperation, aortic surgery, CPB duration, intraoperative transfused erythrocyte volume and perioperative use of intra-aortic balloon pump were independent risk factors for AKI. A postoperative elevation of AKI level was associated with a prolonged duration of mechanical ventilation, intensive care unit stay, postoperative hospital stay, delayed extubation, extubation failure and death. Receiver operator characteristic (ROC) curve showed that AKI classification was a postoperative predictor of delayed extubation, extubation failure and death.

Conclusion: As a common complication after cardiac surgery, AKI is associated with many perioperative risk factors. And the AKI classification is predicator of delayed extubation, extubation failure and death.