(1532) Intraoperative Fluid Resuscitation and Outcomes in Cardiac Surgery

Introduction: The decision to administer additional intravenous fluid (IVF) or to initiate or escalate vasopressor therapy is an essential question in the management of any hypotensive and critically ill patient. In the cardiac surgery patient, administration of excess fluid is known to be associated with multiple complications including atrial fibrillation and acute kidney injury. What is not known however is what constitutes “excess” volume. In this study, we attempt to establish an intraoperative fluid administration threshold above which the rate of postoperative complications increases.

Methods: This was a multi-center retrospective study of patients admitted to NYU Langone Health between July 2020 and July 2023 for elective coronary artery bypass graft or valve replacement surgery. Additional inclusion criteria were age 18 years or older and preoperative ambulation. The primary endpoint was 30-day all cause readmission. A median of 2,500 mL of crystalloid was administered in the intraoperative period. This volume was used as a threshold for determining the complication rates and readmissions of patients who received less than or greater than this amount.

Results: Of 666 screened patients, 320 were included. Patients who received more than 2,500 mL of fluid had a significantly higher 30-day readmission rate (7.2% vs 14.3%, p=0.039). In addition, patients who received greater than 2,500 mL of fluid experienced a longer hospital length of stay (5.1 vs 5.5 days, p=0.009), a greater need for postoperative vasopressors (36.1% vs 52.1%, p=0.005), higher rates of postoperative atrial fibrillation (21.1% vs 34.3%, p=0.008), respiratory failure requiring mechanical ventilation (0.6% vs 7.1%, p=0.001), need for re-exploration (0.6% vs 5.7%, p=0.012), and greater mortality (0% vs 2.9%, p=0.036).

Conclusions: Our study suggests that administering more than 2,500 mL of fluid intraoperatively is significantly associated with higher rates of 30-day readmission, longer hospital length of stay, increased need for vasopressor support, higher rates of postoperative atrial fibrillation, respiratory failure, re-operation, and mortality.