Nerve agents suspected exposure

In general, there were certain tendencies to decrease cholinesterase activity (especially RBC AChE activity) during their work at the department. Some rare examples of suspect intoxications were observed in the cholinesterase monitoring as well as an RBC AChE decrease in workers during their work with high concentrations of nerve agents (e.g. inhalation exposure experiments) (Figure 58.4). 

Table 1. General guidelines for immediate atropine treatment of a nerve agent casualty based upon the suspected route and severity of clinical signs of exposure ...

This section discusses the general principles of treating nerve agent poisoning. The specific treatment of casualties in the six exposure categories (suspected, minimal, mild, moderate, moderately severe, and severe) is addressed in the next section. Terminating the Exposure... 

Suspected, but unconfirmed, exposure to a nerve agent sometimes occurs in an area where liquid agent was present. A person without signs or symptoms may be unsure whether he is contaminated. In such cases, the suspected casualty should be thoroughly and completely decontaminated and kept under close medical observation for 18 hours. If a laboratory facility is available, blood should be drawn for measurement of RBC-ChE activity. 

Since the onset of effects caused by nerve agent exposure may occur as long as 18 hours after skin contact, prolonged observation is prudent. The longer the interval until the onset of signs and symptoms, the less severe they will be, but medical assistance will still be necessary. Since vapor (or inhaled aerosol) causes effects within seconds or minutes, it is extremely unlikely that a suspected asymptomatic casualty would be produced by this route. 

A person having mild exposure to a nerve agent should be thoroughly decontaminated (exposure to vapor alone does not require decontamination) and have blood drawn for measurement of RBC-AChE activity prior to MARK I administration if facilities are available for the assay. As noted above, if there is reason to suspect liquid exposure, the casualty should be observed longer. 

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. 

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