Techniques for assessment of intravascular volume in critically ill patients.

Fluid replacement is considered the cornerstone of resuscitation in the ICU.However, only about 50% of critically ill hemodynamically unstable patients are fluid responsive; furthermore, both under-resuscitation and overzealous fluid administration adversely affect outcome Consequently, the resuscitation of critically ill patients requires an accurate assessment of the patients' intravascular volume status and their volume responsiveness. This paper reviews the evolution and accuracy of methods for assessing fluid responsiveness in critically ill patients.