Infusion rate and plasma volume expansion of dextran and albumin in the septic guinea pig

Background: Intravenous fluid treatment of hypovolaemia in states of increased capillary permeability, e.g. sepsis, is often accompanied by adverse oedema formation. A challenge is therefore to achieve and maintain normovolaemia using as little plasma volume substitution as possible to minimise interstitial oedema. In the present study, we evaluated the importance of infusion rate for the plasma volume expanding effects of 6% dextran 70 and 5% human albumin in a guinea pig sepsis model.

Methods: In this prospective, randomised study, 50 anaesthetised adult male Dunkin-Hartley guinea pigs were used. After laparotomy, sepsis was induced by caecal ligation and incision. Three hours later, an infusion (12 ml/kg) of one of the studied fluids was given either over 15 min (bolus group) or over 3 h (continuous group). A sham group underwent the same surgical procedure but did not receive any fluid.

Results: At the end of the experiment 3 h after the start of infusion, plasma volumes in the continuous group and the bolus group, respectively, were: 47.2 ± 5.3 ml/kg and 36.5 ± 3.9 ml/kg (P < 0.001) for 6% dextran 70, and 47.3 ± 7.5 ml/kg and 39.7 ± 2.8 ml/kg (P < 0.01) for 5% albumin. Plasma volume for the sham group at the same time point was 29.9 ± 3.3 ml/kg.

Conclusions: The study performed on a guinea pig sepsis model showed that the plasma volume expanding effects of fixed volumes of 6% dextran 70 and 5% albumin were greater when given at a slow than at a fast infusion rate.