Prostaglandin E1 as a hypotensive drug during general anaesthesia.

Hypotension induced by prostaglandin E1 (PGE1) infusion (100-150 ng/kg/minute) during halothane anaesthesia to reduce operative blood loss during mastectomy was investigated. PGE1 decreased systolic arterial pressure approximately 34% from pre-administration values. The duration of induced hypotension was about 75 minutes. When the infusion was stopped, blood pressure returned to within 15% of the control with 15 minutes. Heart rate did not change significantly during PGE1 infusion; the pre-ejection period and left ventricular ejection period were shortened. Renal function during the hypotensive period was well maintained. Blood loss during surgery was significantly decreased. These findings suggest that PGE1 can be used safely to control arterial pressure during surgery.