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

Medical Aspects of Chemical Warfareties, availability of both evacuation and further medicalcare is important in the triage decision.Peripherally acting lung-damaging agents inducepulmonary edema that varies in severity; a casualtymight recover with the limited care given at the unitlevelMTF. However, a casualty who complains ofdyspnea but has no physical signs presents a triagedilemma: to evacuate this casualty might encourageothers to come to the MTF with the same complaints,anticipating evacuation from the battle area, butrefusing to evacuate might preclude timely care andpotentially cause an unnecessary fatality, and observingthe individual until signs of illness appear mightalso delay medical intervention until the damage isirreversible. Knowledge about the following physicalmanifestations of peripherally acting lung-damagingagent intoxication may be helpful to the triage officerif a reliable history of the time of exposure isavailable:• The first physical signs, crackles (rales) orrhonchi, occur at about half the time it takesfor the injury to become fully evident. Thus, ifcrackles are first heard 3 hours after exposure,the lesion will increase in severity for the next3 hours.• If no signs of intoxication occur within thefirst 4 hours, the chance for survival is good,although severe disease may ultimatelydevelop. In contrast, if the first sign occurswithin 4 hours of exposure, the prognosis isnot good, even with care in a medical center.The sooner after exposure that symptomsdevelop, the more ominous the outlook.Casualties with crackles or rhonchi 3 hours afterexposure must reach a medical facility that can providecare as soon as possible. Even with optimal care, thechances of survival are not good. It should be emphasizedthat these guidelines apply only to objectivesigns, not the casualty’s symptoms (such as dyspnea).In a contaminated area, where both medical personneland casualties are wearing MOPP 4 gear, it will not beeasy and may not be possible to elicit these signs.In a unit-level MTF, casualties from peripherallyacting lung-damaging agents might be triagedas minimal or expectant, with a separate evacuationgroup for those who require immediate care, if timelyevacuation to a higher-level facility is possible. In alarge, higher-level MTF, these casualties might be classifiedas minimal or immediate because full care canbe provided on-site.Incapacitating AgentsAn incapacitating agent is a chemical warfare agentthat produces temporary disabling conditions thatcan last hours or even days after exposure. Casualtiesshowing the effects of exposure to an incapacitatingagent may be confused, incoherent, disoriented, anddisruptive. They cannot be held at the unit-level MTF,but they should not be evacuated ahead of casualtieswho need lifesaving care unless they are completelyunmanageable and threatening harm to themselves orothers. Casualties who are only mildly confused fromexposure to a small amount of agent, or whose historyindicates they are improving or near recovery, may beheld and reevaluated in 24 hours. In a unit-level MTF,a casualty from exposure to an incapacitating agentmight be minimal or delayed, with little need for highpriority in evacuation. In a higher-level MTF, thesecasualties would be cared for on a nonurgent basis. 7Riot Control AgentsRiot control agents, which include irritant agents(eg, CN [chloroacetophenone]) and vomiting agents(eg, DA [diphenylchlorarsine]), have been availablefor many years and are used in uncontrolled disturbancesto render people temporarily incapacitatedwithout injury, although use of the agents includesrisks of persistent skin effects, eye effects, and allergicreaction after exposure. Decontamination can relieveirritation of symptoms and decrease risk of injury ordelay effects of contact dermatitis. Casualties exposedto riot control agents will most likely not be seen at anMTF, but if they do present with complications, triageaccording to the nature of the injuries. 17TRIAGE BY CATEGORY AND AGENTImmediateNerve AgentsA nerve agent casualty in severe distress would beclassified as immediate. The casualty may or may notbe conscious; may be in severe respiratory distress ormay have become apneic minutes before reaching thefacility; may not have convulsed or may be convulsingor immediately postictal. Often the contents of threeMark I or ATNAA kits (or more) plus diazepam and,possibly, short-term ventilatory assistance will be allthat is required to prevent further deterioration anddeath. In addition, a casualty with involvement of twoor more systems (eg, neuromuscular, gastrointestinal,and respiratory, but excluding effects on the eyes and520