A. Briggs1, J. M. Havens1,2, A. Salim1,2, K. B. Christopher3 1Brigham And Women’s Hospital,Division Of Trauma, Burn, And Surgical Critical Care,Boston, MA, USA 2Brigham And Women’s Hospital,Center For Surgery And Public Health,Boston, MA, USA 3Brigham And Women’s Hospital,The Nathan E. Hellman Memorial Laboratory, Renal Division,Boston, MA, USA
Introduction: Patients undergoing Emergency General Surgery (EGS) have increased risk of complications and death when compared to those undergoing non-emergency general surgery. Acute Kidney Injury (AKI) is a known risk factor for death in critically ill patients. The risk of acute kidney injury in patients undergoing EGS, along with associated outcomes, is unknown.
Methods: We performed a two center observational study of patients treated in medical and surgical intensive care units in Boston between 1997 and 2012. Emergency General Surgery (EGS) was defined by the seven procedures previously shown to account for the majority of the EGS specific operations, complications and mortality in the United States, occurring within 48 hours of ICU admission. The primary end point of AKI was defined as a Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) criteria classification of Injury or Failure occurring up to 5 days after EGS. The designation of ‘AKI requiring renal replacement’ was defined as AKI with subsequent need for renal replacement therapy. We excluded patients with End Stage Renal Disease and those with advanced Chronic Kidney Disease (stages 4 and 5). Adjusted odds ratios were estimated by multi-variable logistic regression models with inclusion of covariate terms thought to plausibly associate with both EGS and AKI. Estimates were adjusted for age, race, Deyo-Charlson comorbidity index, Chronic Kidney Disease stage, sepsis, patient type (medical vs surgical) and hospital.
Results: We studied 59,604 patients who received critical care. The study cohort was 58.8% male, 77.5% white, 46.6% surgical, had a mean age of 57.1 years, and 1,758 (2.9%) of these patients underwent EGS within 48 hours of ICU admission. 3,554 (6.0%) of the cohort patients developed AKI and 757 patients (1.3%) developed severe AKI. For the entire cohort, the 90-day all cause mortality was 13.7%. The adjusted odds of AKI for patients with EGS was 1.65 (95% CI 1.40-1.95; P< 0.001) relative to patients without EGS. The adjusted odds of AKI requiring renal replacement for patients with EGS was 1.83 (95% CI 1.37-2.46; P< 0.001) relative to patients without EGS. Patients who undergo EGS (n=1,758) have an increase in the adjusted odds of 90-day mortality depending on the severity of AKI, with an AKI OR of 3.04 (95%CI 2.15-4.30, p<0.001), and an OR for AKI requiring renal replacement of 4.72 (95%CI 2.67-8.33, p<0.001) relative to the absence of AKI.
Conclusions: ICU patients who undergo EGS have a significant increase in the risk of AKI. The development of AKI in EGS patients is strongly predictive of increased 90 day mortality. The risk and consequences of AKI should be considered when counseling EGS patients prior to operative intervention.