PubMed1976
Acute haemodilution was performed in 10 patients scheduled mainly for vascular surgery. Before induction to anaesthesia 910 +/- 29.1 ml whole blood was taken and simultaneously replaced as follows: 50% of that amount with 3,6% albumin solution, another 50% X 3 with lactated Ringer solution. The haematocrit was thus lowered from 39.8 +/- 1.71 to 28.4 +/- 1.7 vol%. Extensive clotting studies were performed to investigate the early influence of haemodilution on the clotting mechanisms in the time span between the end of blood collection and the point of surgical anaesthesia. The group of patients with normal clotting studies prior to haemodilution has shown a slight and short-lasting hypercoagulability. This has been proven by a shortening of r and k in TEG, by a shortening of non-activated Partial Thromboplastin Time (means activation of the XII and XI factor) and also, by the presence of an activated factor Xa and by an increase of maximum platelet aggregation and of platelet factor 3 availability. This mechanism of clotting activation is similar to the one observed after marked blood loss. It was assumed that this minor, early and short-lasting hypercoagulability has no further influence on the well known usual intra- and post-operative changes in clotting mechanisms (intra-op lowered, post-op enhanced coagulability). In contrast to the patients with normal clotting, a clotting defect due to preexisting liver-cell damage becomes worse during the haemodilution, which method in the presence of hepatic insufficiency therefore is contraindicted. A few additional data on input-output, serum and urine electrolytes and on 2,3 DPG have been gathered during our study. They indicate a positive fluid balance and the necessity for a close watch of electrolytes. The possible trend of 2.3 DPG elevation which has also been found might reflect a compensatory mechanism increasing oxygen transport capacity of haemoglobin if the above described method of haemodilution is used.