 Following IRB approval and written informed patient consent, 40 elective, cardiac surgical patients will be randomized to two different fluid therapy regimens, 5 human albumin only or Lactated Ringers only, beginning in the intraoperative period and up to 6 hours in the intensive care unit. Providers and patients will be blinded to the fluid administered in the operating room and intensive care unit. The primary outcome measure will be the total volume of 5 human albumin or Lactated Ringers given during the study period to maintain specified hemodynamic guidelines. Hemodynamic instability will be defined according to each patients stipulated baseline parameters. Fluid will be administered at the request of providers in the operating room and intensive care unit in compliance with a perioperative fluid algorithm. Outcome measures of hemodynamic instability will include systolic and diastolic blood pressures; mean arterial pressure, central venous pressure, cardiac index, urine output, and vasopressor use. Alveolar-arterial gradient will be assessed between the two choices of fluid to determine any relationship with fluid choice and duration of intubation in the intensive care unit. Blinding of the fluid therapy has not been done in this group of patients so detection of bias towards one of the fluids may be appreciated. 