Fluid resuscitation

See also: Human fluid metabolism

Fluid resuscitation deals with the parenteral administration of fluids to patients, to correct actual, or effective, losses of body fluid. The focus in fluid replacement is on the fluid volume and the osmotic pressure exerted. A given injected liquid, however, may also replace electrolytes (medical) or coagulation factors. Usually, blood cells are needed to replace oxygen-carrying capacity, but there are some cell-free oxygen transport agents, which are administered in some of the fluids mentioned here, again having dual effects, in this case on oxygenation and fluid volume.

Basic compartments

In the simplest case of fluid resuscitation, the basic choice is between crystalloids or colloids. Crystalloid solutions contain only low molecular weight substances, where colloids are based on proteins or polymers of high molecular weight. The first clinical difference between the two is the physiological fluid compartment they expand. Crystalloids, the major component of which is sodium ion, primarily expand the interstitial fluid (i.e., between the cells). Colloids expand the volume of plasma circulating in the blood vessels.

Representative crystalloids	Representative colloids
Normal saline	Human blood plasma
Lactated Ringer's injection	Albumin injection
	Hydroxyethyl starch
	Dextran 70