Elevated Pulse Pressure in Anesthetized Subjects Before Cardiopulmonary Bypass Is Associated Strongly With Postoperative Acute Kidney Injury Stage.

ABSTRACT

OBJECTIVE: To investigate whether pulse pressure (PP) in anesthetized patients undergoing cardiac surgery before and after cardiopulmonary bypass (CPB) is associated with higher postoperative acute kidney injury (AKI) stage. DESIGN: Retrospective cohort of 597 patients undergoing cardiac surgery. SETTING: Single academic health care center. PARTICIPANTS: Adult patients undergoing cardiac surgery requiring CPB (coronary artery bypass grafting, valve, aortic, or combined surgery). INTERVENTIONS: Pulse pressure was assessed during 3 time periods pre- and post-CPB, and in the first postoperative hour in the intensive care unit. Pulse pressure, patient characteristics, and intraoperative variables were evaluated using univariable generalized estimating equation analysis for a relationship with AKI stage. Significant risk factors from the univariable analysis then were evaluated in a multivariable generalized estimating equation analysis. Acute kidney injury stage was defined using the Acute Kidney Injury Network criteria. PRIMARY OUTCOME: Stage of postoperative AKI. MEASUREMENTS AND MAIN RESULTS: Intraoperative prebypass PP was associated independently and significantly with postoperative AKI stage (odds ratio 1.0107; 95% Confidence Interval, 1.0046-1.0168; p = 0.0005). For every 1-mmHg increase in PP, the odds of a higher AKI stage increased 1.07%. The 2 other periods were not found to be significant predictors of AKI stage. CONCLUSION: During general anesthesia prior to initiation of CPB, elevated PP is significantly predictive of postoperative AKI stage. This finding merits further research.