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

Medical Aspects of Chemical Warfareafter exposure. For example, mustard, a vesicant, maybe on the skin for many hours before a lesion becomesnoticeable. Thus, it is likely that the agent has beencompletely absorbed or has evaporated from the skinby the time the casualty reaches the MTF, and the smallamount unabsorbed, or absorbed during a wait fordecontamination, is very unlikely to be significant.The process of patient decontamination must be factoredinto the triage decision. (It must be rememberedthat triage refers to priority for medical or surgicalcare, not priority for decontamination. All chemicalcasualties require decontamination. Although a casualtyexposed to vapor from a volatile agent such ascyanide, phosgene, or a nerve agent may not appearto need decontamination, verifying that no liquid ispresent on the casualty is difficult.) In a contaminatedenvironment, emergency care is given by personnelin MOPP 4, the highest level of protective gear, whichlimits their capabilities. After receiving emergencycare, a casualty must go through the decontaminationstation before receiving more definitive care ina clean environment. Decontamination takes 10 to 20minutes. As a rule no medical care is provided duringthis time or during the time spent waiting to begin thedecontamination process. Therefore, before leaving theemergency care area, patients must be stabilized to anextent that their condition will not deteriorate duringthis time. If stabilization cannot be achieved, thetriage officer must consider this factor when makingthe triage judgment. If the casualty has torn clothingor a wound suspected to be the source of contamination,a different type of decontamination—immediatedecontamination—must be performed at the triage oremergency treatment station in the dirty or chemicallycontaminated area.Casualties exposed to certain chemical agents suchas nerve agents may be apneic or nearly apneic; one ofthe first interventions required is assisted ventilation.Special, air-filtering assisted ventilation equipment, achemical mask-valve-bag device (called resuscitationdevice, individual chemical), is available for use in achemical environment. However, personnel availableto provide ventilator assistance in the contaminatedenvironment are likely to be limited. Also, if a briskwind is present and the medical facility is far upwindfrom the source of contamination, very little agentvapor will remain in the air. If no air-filtering ventilationequipment is available, medical personnel mustdecide whether to ventilate with air that is possiblyminimally contaminated or let the casualty remainapneic. Once assisted ventilation is begun, the careprovider is committed to the process and cannot carefor other casualties, so the number of medical personnelavailable in the contaminated area influences theventilation decision. However, a walking woundedcasualty (in the minimal category) can quickly betaught how to ventilate other casualties. 7Treatment, Decontamination, and Transport LinkageTriage is always linked to treatment; in a masscasualty event, triage and treatment are also linked totransport. In a chemical weapons mass casualty event,decontamination is also linked, and transport is fromthe contaminated environment. This linked processoccurs at the incident site, and is somewhat duplicatedat the MTF; however, different statutory codes, policies,and requirements are relevant in each place. Asthe preparedness and response efforts for homelandsecurity mature, the tactics, techniques, and proceduresused in military settings or homeland settings are converging.Likewise, the regulatory statutes, includingbest practices, certification processes for equipment,training, and competencies, are showing a pattern ofconvergence. Further alignment should be driven bysuch initiatives as development of national resourcetyping systems (discussed in Other Triage Systems,below) in support of national preparedness goals.During response preparations, the triage and treatmentteams are best placed at naturally occurringbottlenecks as patients are processed through thedecontamination corridor (Figure 15-1). At least threetriage locations should be placed at the incident site.Triage and treatment teams must integrate their workwith patient transport teams (litter bearers and ambulancestaff). They must also integrate with decontaminationteams, which may be comprised of personnelwith very limited medical training. Medical oversightof the patients must be clearly defined and understoodby all personnel, including recognition of and properalerts for changes in patient condition, continuationof any supportive measures, and strict adherence toprotocol and procedure.The initial casualty collection point is located nearthe border of the hot and warm (contamination reduction)zones. This location allows for initial collectionof nonambulatory victims from the incident site inthe hot zone and provides shorter distances and cycletimes for teams retrieving the casualties from the incidentsite. It also provides a working environment formedical personnel who are initially uncontaminated.Antidote administration and airway managementare the mainstays of treatment at this point. The nextbottleneck generally occurs on both sides of the decontaminationshelter. Current methods for mass casualtydecontamination allow for very limited throughput,even by the most experienced of teams with the besttechnology, leading to a backup of patient flow at the514