Inhalational exposure to nerve agents.

The respiratory system plays a major role in the pathogenesis of nerve agent toxicity. It is the major route of entry and absorption of nerve agent vapor, and respiratory failure is the most common cause of death follow-ing exposure. Respiratory symptoms are mediated by chemical irritation,muscarinic and nicotinic receptor overstimulation, and central nervous system effects. Recent attacks have demonstrated that most patients with an isolated vapor exposure developed respiratory symptoms almost immediately. Most patients had only mild and transient respiratory effects, and those that did develop significant respiratory compromise did so rapidly. These observations have significant ramifications on triage of patients in a mass-casualty situation, because patients with mild-to-moderate exposure to nerve agent vapor alone do not require decontamination and are less likely to develop progressive symptoms following initial antidote therapy. Limited data do not demonstrate significant long-term respiratory effects following nerve agent exposure and treatment. Provisions for effective respiratory protection against nerve agents is a vital consideration in any emergency preparedness or health care response plan against a chemical attack.