Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical Warfarewith the injector. In this case, because of the volumedisparity, multiple atropine autoinjectors or ATNAAsare required to compensate for the volume of thetracheobronchial tree.For severely exposed casualties, the initial dose ofatropine should be at least the 6 mg from the threeautoinjectors. An additional 2 mg or 4 mg should alsobe given intravenously if the capability is availableand if the casualty is not hypoxic. Ventilatory supportmust be started before IV atropine is given. If additionalatropine cannot be given intravenously, thenthe amount should be given intramuscularly. The totalinitial dose of atropine can be as much as 10 mg, butthis dose should not be exceeded without allowing atleast several minutes for a response. Further atropineadministration depends on the response. If secretionsdecrease or if there are attempts at breathing, it maybe prudent to wait even longer before administeringadditional atropine. All three injectors of 2-PAM Clshould be given with the initial 6 mg of atropine, butno more oxime should be given for an hour.Possibly the most critical factor in the treatmentof severely exposed casualties is restoration of oxygenation.Atropine alone might restore spontaneousbreathing in a small number of apneic individuals.Ideally, an apparatus that delivers oxygen underpositive pressure will be available. Even an RDIC or amask-valve-bag apparatus used with ambient air willprovide some assistance.When the contents of three Mark I kits or ATNAAsare administered together to a severely poisonedcasualty, diazepam should be administered with thecontents of the third Mark I or ATNAA, whether ornot there are indications of seizure activity. The risk ofrespiratory depression from this amount of diazepamgiven intramuscularly is negligible.Hypotension need not be treated, at least initially.Generally the restoration of oxygenation and the increasein heart rate caused by atropine, aided perhapsby the hypertensive effects of 2-PAM Cl, will result inelevation of the blood pressure to an acceptable level.Even with adequate oxygenation and largeamounts of atropine, immediate reversal of all of theeffects of the nerve agent will not occur. The casualtymay remain unconscious, without spontaneous respiration,and with muscular flaccidity or twitching forhours. After respiration is at least partly spontaneous,secretions are minimized, and the casualty is partlyalert, continued monitoring is necessary. Muscularfasciculations may continue for hours after the casualtyis alert enough and has strength enough to getout of bed.RETURN TO DUTYVarious factors should be considered before an individualwho has been a nerve agent casualty is returnedto duty. In an industrial setting (depot or laboratory),the criteria for reactivation are that the individual ’ sRBC-ChE activity must have returned to greater than90% of its baseline value and that the individual isotherwise symptom-free and sign-free.In a military field setting, however, ChE activitymeasurements are not available, and the need to returnthe fighting soldier to duty may be more acute. Thedecision is largely a matter of judgment and shouldinclude the following considerations:• If exposed to nerve agent again, will thesoldier be in greater danger because of theprevious exposure?• How well can the soldier function?• What is the military need for the soldier?In the absence of blood ChE measurements, it is difficultto predict whether a soldier would be at greaterrisk from a second nerve agent exposure. Even an individualwith rather mild effects (miosis and rhinorrhea)may have marked ChE inhibition. On the other hand,if an oxime (contained in the Mark I kit or ATNAA)was given and the agent was one susceptible to oximetherapy, then the enzyme activity may be restored. Ina field setting, neither the identity of the agent nor thedegree of ChE inhibition or restoration will be known.In any case, proper use of mission-oriented, protectiveposture, level 4 gear should protect against furtherexposure. The soldier should be returned to activeduty if able and needed.A soldier who has had signs of severe exposurewith loss of consciousness, apnea, and convulsions,may have milder CNS effects for many weeks afterrecovery from the acute phase of intoxication. Exceptin dire circumstances, return to duty during thisperiod should not be considered for such casualties.An individual with relatively mild effects (miosis,dyspnea, rhinorrhea) may be returned to duty withinhours to several days following exposure, dependingon the assignment and the military need. However,the soldier may experience visual problems in dimlight and may have mental lapses for as long as 6 to 8weeks, 18,45 and these factors must be considered beforereturning a soldier to duty. In one case, troops whowere symptomatic (miosis, rhinorrhea, dyspnea) as aresult of nerve agent exposure carried out maneuvers(including firing weapons) in a satisfactory, although194