Circulating blood volume in patients with subarachnoid haemorrhage.

To establish the fluid management for patients with subarachnoid haemorrhage (SAH), circulating blood volume (BV) was measured by pulse-spectrophotometry using indocyanine green (ICG) in 34 cases with SAH and 20 cases with neurosurgical disorders as control. BV measured immediately after induction of anaesthesia was lower in cases with SAH than that in controls. (62.8+/-12.3 vs. 73.3+/-11.2 ml/kg, p<0.01). In cases with SAH, the BV was significantly decreased in females (p<0.05) but not so significantly in males. In female cases with SAH, reduced BV was increased 3 days after operation (p<0.01). In conclusion BV is decreased in cases with SAH, especially in females. Active fluid therapy may be necessary when temporary vascular occlusion is required during aneurysm surgery. Since hypovolaemia may cause symptomatic vasospasm, BV measurement with pulse-spectrophotometry may provide useful information to insure normovolaemia.