Nerve agents relevance

Physical Properties of the Nerve Agents Relevant to Vapor Generation... 

With the analytical methodology available, it appeared possible to measure nerve agents at the toxicologically relevant level. This capability allowed to measure the toxicokinetics of nerve agents after a variety of exposure routes at several doses, and to determine the time period for which... 

There are clear ethical constraints that prevent human research that could definitively answer the questions of concern regarding the military operational and civilian health risks of exposure to low-levels of chemical warfare nerve agents. Only three sources of relevant human data are available for analysis. These data are from either past human volunteer studies, reports based on accidental exposures, or reports of the consequences of malicious releases of the agents. While these sources are valuable, the data have some limitations for deriving dose-response relationships because of inferior analytical and clinical methods or the lack of precise estimates of exposure. 

For an exposed military population, the dose of a CWA considered to be "low-level" is the lowest dose that results in either an immediate observable adverse health effect or which causes operationally relevant performance decrements. The most sensitive marker of an observable health effect and the purported cause of early significant performance degradation is nerve agent-induced miosis. While various exposure durations can be considered in the planning of future research, a one-time exposure or continuous exposures lasting from minutes to several hours should be the primary target duration of exposure. 

The therapeutic efficacy of oximes is usually focused on the evaluation of the protective ratio (PR), which is the ratio of the LD50 value of nerve agents for therapeutically protected animals to the LD50 value of nerve agents for unprotected animals. The authors usually publish data obtained from experiments where a combination of atropine and an oxime is used as an antidotal treatment because this possibility is much more relevant to anticipated military use than atropine or oxime alone. The results of published experiments are listed in Table 4(10, 32-47). 

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