Physicochemical changes during haemorrhage and following infusion

Interstitial fluid pressure (IFP) and plasma colloid osmotic pressure (plasma COP) were measured in dogs following acute haemorrhage and following the infusion of saline, 10% dextra 40 in saline and 3% dextran 40 in lactated Ringer's solution. Exsanguination decreased IFP, plasma COP and total plasma protein and albumin concentrations, and increased plasma glucose concentration and osmotic pressure. A massive infusion of physiological saline increased IFP, and decreased plasma COP and total plasma protein and albumin concentrations. The volume of saline infused correlated with the increase in IFP. When a 10% dextran 40 saline solution was used, there was a marked increase in plasma COP but a decrease in IFP. When 3% dextran 40 in lactated Ringer's solution was infused, IFP was little affected in the early stage, but gradually increased thereafter. Plasma COP increased slightly immediately after infusion, but remained near the pre-exsanguination value for at least 3 h.