HEMODILUTION INDUCES A HYPERCOAGULABLE STATE

It has been suggested that haemodilution with saline may increase whol e blood coagulation. This study was conducted in two parts. First, we investigated the effect of in vitro dilution of blood with saline on w hole blood coagulation as measured by the thrombelastogram (TEG). Bloo d (4 ml) was diluted with 0.9% saline 1 mi and coagulation compared wi th that of an undiluted control specimen obtained concurrently from th e same subject. In the second part, the study was repeated using a mod ified gelatin colloidal solution (Haemaccel) as the diluent. The r tim e, k time and r + k time were decreased relative to control in both di luent groups. The alpha angles were increased compared with control in both groups while maximum amplitude was unchanged in the Haemaccel di luted group. We conclude that haemodilution per se increases the coagu lability of whole blood in vitro, but that saline haemodilution has a more marked effect on final clot strength.