Domestic swine model for the assessment of chemical warfare agent-anesthetic interactions: Some effects of sulfur mustard

A domestic swine model was developed to examine the interaction of chemical warfare agents with anesthetics and other drugs used during general anesth esia, Animals were fully instrumented, and clinically relevant physiologica l parameters were monitored throughout the experimental procedures. Exposur e of animals under halothane anesthesia to the chemical warfare agent sulfu r mustard (HD; 1 mg/kg intravenous) produced mild signs of systemic intoxic ation during the subsequent 5 hours. Induction doses of ketamine 1 hour aft er HD exposure resulted in periods of profound apnea, with continued respir atory distress for the next 2 hours. When animals were treated with HD 1 ho ur after the initiation of ketamine anesthesia, severe and persistent convu lsion-like muscular activity was observed within 45 minutes of HD administr ation. This nonpurposeful activity was not ameliorated by diazepam but was dramatically reduced or eliminated by resumption of halothane anesthesia. T reatment of HD-intoxicated pigs with succinylcholine produced a prolonged a pnea resulting in death. In these apparently mildly HD-intoxicated animals, the introduction of ketamine or succinylcholine can rapidly induce potenti ally life-threatening situations.