Crystalloid Fluids and Cardiac Surgery

Inflamed patients admitted to the intensive care unit after cardiac surgery received large volumes of crystalloid fluids as standard care procedure. The goal is to control the balance between the initial pro-inflammatory phase and the subsequent/compensatory anti-inflammatory phase, the later being associated to immune fatigue and the apparition or re-activation of infections. Infectious complications are responsible for the increased rate of morbidity and mortality in this cardiac surgery population. The inflammatory impacts of each of the crystalloid fluids administered to the patient are still ill-defined and represent an opportunity to better control the hyperinflammation and/or immunosuppression often observed following cardiac surgery. Hence, the investigators will evaluate the activation of the immune system following crystalloid fluid (either Normal saline (NS), PlasmaLyte (PL) or Ringer's Lactate (RL)) administration in this population with regard to one recurrent clinical issue, i.e renal failure. The hypothesis is that LR is less ''immuno-activator'' on monocytes than NS and PL. The objectives are: 1-evaluate the inflammatory profiles of each of the crystalloid fluids in consent cardiac surgery patients during their stay in the intensive care unit by studying white blood cell phenotypes and inflammatory cytokines present in plasma and 2-evaluate the impacts of crystalloid fluids in vitro using white blood cell from cardiac surgery patients obtained before surgery.