Crystalloid Fluids and Cardiac Surgery

All cardiac patients admitted to the intensive care unit after surgery received crystalloid fluids as standard care procedure. 3 crystalloid fluids can be used during their stay: Normal Saline, PlasmaLyte or Ringer\'s Lactate. They differ in their respective composition, mainly in chloride and sodium concentrations. Inflammatory consequences of the crystalloid fluids used in this population are unknown. The investigators plan to evaluate which one of the three fluids mentioned above is advantageous in cardiac surgery patients with regards to reduced rate of infection and renal failure.