High volumes of intravenous fluid during cardiac surgery are associated with increased mortality

INTRODUCTION Positive fluid balance during abdominal surgery has been associated with increased morbidity. We hypothesized that administration of large volumes of intravenous fluids in cardiac surgery is associated with increased mortality. METHODS Retrospective analysis of data on 1358 patients who underwent cardiac surgery from 2001 to 2005 at two major hospitals in Western New York. Patients were divided in to those who received intravenous fluids above the median volume (3.9 L) and those who received less than the median volume of intra-operative fluid. Acute Kidney Injury Network criteria based on serum creatinine were used to define Acute Kidney injury. RESULTS Logistic regression and Cox-proportional models showed increased 90 day mortality (HR -2.8, 95% CI -1.16-7.01) in those patients who received greater than the median volume of intravenous during cardiac surgery. This was confirmed with propensity score analysis. Furthermore, the marginal effects analysis revealed that after about 4.0 liters of intravenous fluid, the survival probability falls significantly in cardiac surgery patients. CONCLUSIONS Administration of large volumes of intra-operative intravenous fluid is independently associated with an increase in 90 day mortality in cardiac surgery.