Changes in the composition of human blood by intravenous saline infusion with and without simultaneous controlled...

The pattern of dilution and re-concentration of the blood in connection with intravenous infusion of saline-alone or in combination with bleeding-was studied in volunteers. In these we followed the immediate and delayed changes in 16 common haematological and clinical chemical variables in relation to such infusions. In one group 15 ml/kg was given in an hour. In another, 2500 ml was given during a bleeding of 870 ml. These dosage principles are elements of a recommended scheme of peroperative infusion therapy. Estimated by the haemoglobin changes the blood volume was expanded by 10% at the end of infusion alone and by 5% at the end of bleeding/infusion. This expansion, which was of short duration, was accompanied by initial reductions of 15 and 29%, respectively, in serum protein concentration. Three diagnostic enzymes were diluted less systematically. Components of low molecular weight were little affected, except serum calcium, which was 21% decreased at the end of bleeding/infusion. The larger part of the reconcentration took place in the next six hours. In this phase an entry of protein into the blood was demonstrated in both test groups. In contrast to creatininium the carbamide continued decreasing in this time interval. As demonstrated in a control group, other factors than infusion and bleeding contributed on a limited scale to the shift in plasma variables.