Capillary Leak and Starches

Abstract

SUMMARYOne of the earliest features of an acute inflammatory response is an increase in vascular permeability, which allows plasma proteins, including albumin, to move into the interstitial space and cause edema. Systemic capillary permeability is amplified by the kidney and can be monitored by measurement of low‐level urine albumin excretion in the 20 to 200 mg/L range (microalbuminuria). Microalbuminuria reflects rapid changes in systemic capillary permeability, which increases dramatically within a few minutes of injury and usually returns to normal within 6 to 12 hours. Failure of capillary permeability to return to normal is an early predictor of later pulmonary dysfunction and organ failure. Recent studies suggest that, following trauma or surgery, medium‐molecular weight hydroxyethyl starches as opposed to human albumin or gelatine solutions markedly reduce capillary leak, improve pulmonary gas exchange and organ function, and downregulate the acute inflammatory response. It is not clear which mechanisms underlie this microvascular protective effect although blocking of endothelial cell activation may be involved.