Fluid management and electrolyte balance

Abstract

Cardiac surgery is responsible for profound modification in body water distribution, electrolyte plasma concentration, and acid-base balance. Maintaining homeostasis must take into account the kind of surgery, the alterations due to anesthesia, the effects of cardiopulmonary bypass, patient's comorbidities, and his own response to surgical stress. The ideal approach to perioperative fluid management is still debated in all clinical contest and in cardiac surgery patients in particular, since a load of fluid is generally needed because of cardiopulmonary bypass priming. The debate involves the kind of fluid to use (crystalloids vs. colloids, colloid vs. colloid, balanced vs. unbalance solutions) and the amount of fluid to administer (liberal, restrictive, goal-directed therapy). In this debate economics interests have influenced literature productions and results, leading more difficult the interpretation of many results and complicating clinical application of scientific founds in routinely practice. Electrolytes are always modified after cardiac surgery. With respect to the past, the benefit of their administration (in particular calcium) has been discussed in literature. In this chapter the basis of fluid and electrolyte management in cardiac surgery patient is explained, through understanding physiology and pathophysiology and considering with critical approach literature evidences.