ORGANOPHOSPHATE POISONING - PERIPHERAL VASCULAR-RESISTANCE - A MEASURE OF ADEQUATE ATROPINIZATION

We report severe organophosphate poisoning complicated by hypotension and ischemic sequelae in two patients with pre-existing vascular disea se. Both patients had a low total peripheral resistance and high cardi ac output that were significantly reversed by doses of atropine in exc ess of those required to control other muscarinic symptoms. Cerebral i nfarcts and gangrene requiring a below knee amputation were complicati ons of the poisonings. It is proposed that the ischemic complications are due to paradoxical vasoconstriction by acetylcholine at sites of e ndothelial injury. One patient, who had taken fenthion, also had a sig nificantly delayed peak and prolonged, 2-3 week, systemic toxicity. We propose that stability of the plasma cholinesterase at 6 to 8 h after temporarily suspending oxime provides a rapid guide to the duration o f therapy, especially in patients whose complications make clinical as sessment difficult: