ABSTRACT
This chapter focuses on intravenous fluid resuscitation or the attempt to restore adequate circulatory volume in absolute or relative hypovolaemic states during the early stages of critical illness. A more rational approach would be to employ oxygen transport variables and measurements of end-organ failure, such as plasma lactate levels, to make inferences about tissue oxygenation and the need for red blood cell transfusion. The major constituent of all commonly available crystalloid fluids is the inorganic salt sodium chloride, which is the most abundant solute in the extracellular space. The large variety of resuscitation fluids available, both colloids and crystalloids, underlines our continued failure to identify the best choice of resuscitation fluid for the shocked patient. The colloid-versus-crystalloid argument will be revisited and reference will be made to the emerging role of hypertonic fluids in resuscitation. Crystalloids are isotonic sodium-rich fluids that are devoid of large molecules and tend to distribute between the intravascular and interstitial spaces.
