Extracellular fluid volume and distribution in relation to changes in plasma colloid osmotic pressure after major...

This prospective randomized study deals with the changes in magnitude and distribution of the extracellular fluid volume (ECV) and the relation between such changes and the plasma colloid osmotic pressure (COPP) in patients having abdominal aortic surgery. Two groups of thirteen patients each received whole blood to replace the blood loss. One group (ALB) had additionally 80 g albumin administered on the day of operation and 20 g the following 3 days, the other group (NON-ALB) did not receive extra albumin. In the ALB group ECV decreased from 9.3 +/- 1.71 (= 147 ml/kg) to 8.4 +/- 2.01 (NS) on the first postoperative day (p.o.d.) and to 9.2 +/- 2.5 1 (NS) on the fourth p.o.d. In the NON-ALB group the preoperative ECV of 8.1 +/- 1.11 (= 125 ml/kg) was unchanged on the first p.o.d. and 8.4 +/- 1.41 (NS) on the fourth p.o.d. The differences between the groups were non-significant. The post-operative changes observed in ECV were not related to COPP in the range 33 mmHg to 21 mmHg. The ratio between plasma volume (PV) and ECV was 0.35 +/- 0.06 preoperatively in both groups. Postoperative changes were non-significant and no correlation between COPP and PV/ECV could be found. In the present study the distribution of ECV between plasma and interstitium was found to be independent of COPP in the interval 33-21 mmHg. Furthermore, no obligatory contraction or expansion of ECV occurred after major elective surgery.