Dyspnea nerve agent exposure

The initial effects of nerve agents depend on the dose and route of exposure. A small inhalation exposure from nerve agent vapor causes a response in the eyes, nose and airway, such as miosis, conjunctival injection, eye pain, rhinorrhea, bron-choconstriction, excessive bronchial secretions, and mild to moderate dyspnea (9,13,18). Larger exposures cause central nervous system effects within seconds to minutes, including loss of consciousness, seizures, and central apnea. Death can occur within 5-lOmin of a lethal dose, usually due to respiratory failure from the combined effects of respiratory muscle paralysis, loss of airway control and profuse bronchorrhea (13,14). 

A tight chest or shortness of breath is another typical complaint following exposure to small amounts of nerve agent vapor. Dyspnea (difficult or labored breath-... 

Impairment of breathing is an early effect of exposure to nerve agent vapor or aerosol. When the exposure is small, the casualty may have mild to severe dyspnea, with corresponding physical findings, and the impairment will be reversed by the administration of atropine. If the distress is severe and the casualty is elderly or has pulmonary or cardiac disease, the antidote may be supplemented by providing oxygen by inhalation. In most other circumstances, supplementation with oxygen is unnecessary. 

An individual with mild or moderate dyspnea and possibly with miosis, rhinorrhea, or both can be classified as having a mild exposure to nerve agent. The symptoms indicate that the casualty has been exposed to a nerve agent vapor and may or may not have been contaminated by a liquid agent. 

A casualty who has had moderate exposure to either a nerve agent vapor alone or to vapor and liquid will have severe dyspnea, with accompanying physical signs, and probably also miosis and rhinorrhea. The casualty should be thoroughly decontaminated (Remember exposure to vapor alone does not require decontamination) and blood should be drawn for assay of RBC-ChE activity if assay facilities are available. The contents of three MARK I kits and diazepam should be given if the casualty is seen within minutes of exposure. If seen later than 10 minutes after exposure, the casualty should receive the contents of two kits. Additional atropine should be given at 5- to 10-minute intervals until the dyspnea subsides. No more than three MARK I kits should be used however, additional atropine alone should be administered if the contents of three kits do not relieve the dyspnea after 10 to 15 minutes. If there is reason to suspect liquid contamination, the patient should be kept under observation for 18 hours. 

Primary failure of respiration after exposure to toxicants other than nerve agents suggests a severity of exposure that requires intensive medical support at this point, a triage decision may be needed. The presence of wheezing indicates severe bronchospasm, which requires immediate therapy. The presence of dyspnea necessitates careful observation of the patient for at least 4 to 6 hours, until severe, potentially lethal respiratory damage can be reasonably excluded. 

The general symptoms of exposure to a nerve agent in gas form can be remembered by the acronym DUMBELS diarrhea, urination, miosis, bronchoconstric-tion (dyspnea, wheezing), emesis (vomiting), lacrimation, and salivation. Some prefer the acronym SLUDGEM salivation, lacrimation, urination, diarrhea, gastric upset, emesis, and miosis (Table S3.1). 

Nerve agents are organophosphates (OPs). Acute exposure to OPs can cause muscarinic, nicotinic, and CNS signs. Muscarinic effects include salivation, lac-rimation, urination, dyspnea, diarrhea, and emesis (SLUDDE), along with miosis, bradycardia, hypotension, and bronchoconstriction. Nicotinic effects include... 

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