Effect of bleeding and hypervolaemic haemodilution on traumatic vasospasm in rabbits.

The effect of bleeding (20% of total blood volume) and of hypervolaemic haemodilution with dextran infusion (20% of total blood volume) on traumatic vasospasm was studied in the central ear arteries of 10 rabbits. The blood pressure dropped significantly after bleeding and the packed cell volume was significantly lower after dextran infusion. Neither treatment had any effect on the duration, intensity or severity of the vasospasm. The results suggest that moderate changes in blood volume do not influence traumatic vasospasm.