Review Article

Acute Kidney Injury Subsequent to Cardiac Surgery

^* Division of Cardiothoracic Surgery, Maine Medical Center, Portland, Maine
^† Departments of Medicine and Community and Family Medicine, The Dartmouth Institute for Health Policy and Clinical Practice and Section of Cardiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire

Address correspondence to: Robert S. Kramer, MD, Division of Cardiothoracic Surgery, Department of Cardiac Services, Maine Medical Center, 22 Bramhall Street, Portland, ME 04102. E-mail: Kramer@mmc.org

Received: 1 June 2014
Accepted: 17 February 2015

Abstract

Acute kidney injury (AKI) after cardiac surgery is a common and underappreciated syndrome that is associated with poor short- and long-term outcomes. AKI after cardiac surgery may be epiphenomenon, a signal for adverse outcomes by virtue of other affected organ systems, and a consequence of multiple factors. Subtle increases in serum creatinine (SCr) postoperatively, once considered inconsequential, have been shown to reflect a kidney injury that likely occurred in the operating room during cardiopulmonary bypass (CPB) and more often in susceptible individuals. The postoperative elevation in SCr is a delayed signal reflecting the intraoperative injury. Preoperative checklists and the conduct of CPB represent opportunities for prevention of AKI. Newer definitions of AKI provide us with an opportunity to scrutinize perioperative processes of care and determine strategies to decrease the incidence of AKI subsequent to cardiac surgery. Recognizing and mitigating risk factors preoperatively and optimizing intraoperative practices may, in the aggregate, decrease the incidence of AKI. This review explores the pathophysiology of AKI and addresses the features of patients who are the most vulnerable to AKI. Preoperative strategies are discussed with particular attention to a readiness for surgery checklist. Intraoperative strategies include minimizing hemodilution and maximizing oxygen delivery with specific suggestions regarding fluid management and plasma preservation.