Immediate Changes in Estimated Cardiac Output and Vascular Resistance after Co60Exposure in Monkeys.

摘要

Aortic blood flow velocity, blood pressure, and heart rate were recorded in 12 unanesthetized, nonperforming monkeys during exposure to 1000 rad Co60 at 129-164 rad/min. The first post-radiation changes were seen within 3-4 min of the exposure's start and included tachycardia, a transient hypotension secondary to a loss in peripheral resistance, and a brief increase followed by a decrease to subnormal levels in cardiac output. Lowest cardiac output occurred between 10-20 min postexposure while blood pressure and peripheral resistance were recovering. It was proposed that the concurrent combination of low cardiac output, low blood pressure and supranormal peripheral resistance might sufficiently attenuate cerebral perfusion temporarily to account for the transient behavioral decrements often seen during this time. Histamine release was postulated as responsible for this vascular shock syndrome. (Author)