Extra protein loss not caused by surgical bleeding in patients with ovarian cancer

[corrected] Clinical experience in patients with ovarian cancer has shown special difficulties in maintaining cardiovascular stability during surgery.

To evaluate the causes for this observation, 15 patients with benign ovarian tumours (group I) and 13 patients with ovarian cancer (group II) were investigated perioperatively. Plasma volume (indocyanine green-dilution technique), haematocrit, plasma protein concentration, mean arterial pressure, heart rate, and central venous pressure were measured immediately before and after cytoreductive surgery.

Normal values of blood-, plasma-, and red cell volume were determined preoperatively in both groups, and in relation to body surface area there were no intergroup differences of these parameters. In group I, the significant decrease in red cell volume of 313 ml postoperatively was compensated for by an increase in plasma volume of 371 ml (median values). In contrast to group I, the decrease in red cell volume of 328 ml in group II was not related to a significant increase in plasma volume, so that blood volume postoperatively was 483 ml lower than preoperatively, although the same standardized infusion regimen as in group I was applied. Patients of group II had a significantly higher loss of intravascular protein (49 g vs 13 g in group I), which left the intravascular space by another way than by surgical bleeding. This extra protein loss is termed Intraoperative Protein Shift (IPS).

IPS could be an important quantity in perioperative fluid balance. We assume that different surgical procedures predispose to occurrence of differing amounts of IPS.