Colloid osmotic pressure in health and disease

The use of synthetic colloids has become commonplace in the treatment of cr itically ill animals. The theoretical benefits of colloid compared with cry stalloid fluid therapy for increasing plasma volume include a more rapid an d longer-lasting fluid resuscitation with cola lesser fluid volume necessar y to achieve the same level of resuscitation, and reduced loids, a lesser f luid volume necessary to achieve the same level of resuscitation, and reduc ed risk of edema formation. These benefits are achieved, in part, by increa sing or maintaining the patient's colloid osmotic pressure (COP) to retain fluid within the vasculature and limit extravasation of fluid into the inte rstitium. COP, and ultimately fluid balance, are normally highly dependent on the concentration of albumin within the vasculature. Understanding how C OP is affected in different conditions (e.g., hypovolemia, sepsis, systemic inflammatory response syndrome, acute and chronic hypoalbuminemia) can gui de clinicians in the appropriate uses of colloid therapy.