The fluid challenge

It is very hard to find a precise definition for what is one of the most commonly carried out interventions on intensive care units (ICUs) around the world. A fluid challenge is commonly understood to be a diagnostic intervention designed to give an indication of whether a patient with hemodynamic compromise will benefit from further fluid replacement. The principle is to administer a pre-determined volume of intravenous fluid over a short period of time while measuring a change in the patient’s cardiovascular parameters. The aim is to differentiate hypovolemia, or relative hypovolemia, which might improve with further fluid, from cardiac failure or a full intravascular volume in which case further fluid will not improve things and may cause deterioration.