Plasma protein loss during surgery: Beneficial effects of albumin substitution

Plasma protein loss during abdominal surgery is a known phenomenon, but its possible pathophysiological relevance has remained unknown. The present st udy evaluates the effects of albumin substitution on systemic and local hem odynamics and cellular interactions in the mesenteric microcirculation, Rat s underwent median laparotomy and exteriorization of an ileal loop for intr avital microscopy of the mesenteric microcirculation. Plasma protein concen trations, systemic and local hemodynamics were recorded during the follow u p period, with or without albumin substitution. Depending on the time cours e of plasma protein loss in control experiments, 80% of the calculated prot ein loss was infused during the first 2 h of surgery, and the other 20% ove r the following 5 h of intravital microscopy. The control group received a continuous infusion of normal saline. Plasma protein loss was mainly due to loss of albumin. A significant increase in adherent and rolling leukocyles was observed during the course of mesenteric exteriorization, which was al most entirely reversed by albumin replacement. Albumin substitution led to stabilisation of mean arterial pressure and abdominal blood flow and also a ttenuated reductions in arterial base excess. Albumin infusions to replace plasma protein loss may be a simple and effective measure to attenuate micr ocirculatory disturbances and may be of benefit in patients undergoing abdo minal surgery.