Triage nerve agents

Be able to triage nerve agent attack patients into groups with mild, moderate, or severe poisoning. 

The choice of appropriate treatment for nerve agent intoxication depends on the agent as well as extent and route(s) of exposure. Very mild exposure to nerve agent vapor may necessitate only decontamination and observation severe exposure to vapor or liquid requires immediate decontamination, antidote administration, artificial respiration, monitoring, and supportive therapy over hours to multiple days (ATSDR, 2007 Sidell, 1997 Vale et al, 2007 Pulley and Jones, 2008). Convenient triage classifications have been developed by ATSDR (2007) in collaboration with the US Army Medical Research Institute of Chemical Defense. 

Effective triage requires the presence of a triage officer who is trained to identify the type of casualties that will be sorted. For instance, a person contaminated with a liquid nerve agent who arrives as an ambulatory casualty may deteriorate rapidly once the agent is absorbed. Triage officers are in a key position, and the individual must be capable of making quick and frequently difficult decisions. Also, triage officers must be very familiar with the medical staff and the hospital s capabilities and limitations. 

Figure 1. The principles of triage in the EMT point and Field hospital for nerve agent casualties which used in the ASSISTEX-I...

Following the Japanese nerve agent releases, substantial numbers of casualties presented to hospital over a short time period, which stretched the resources available. Hence, each country and every hospital should now have a major accident plan that covers deliberate chemical releases, including nerve agents. This plan should be tested at least annually. It should include arrangements to triage substantial numbers of non-poisoned casualties, as well as those who are severely poisoned and require urgent treatment and admission. 

At the St. Luke s International Hospital, one of three cardiopulmonary arrest victims and two respiratory arrest patients recovered fully and have been socially rehabilitated. This is important and shows that triage in cases of chemical terrorism must be different from that used in large-scale natural disasters. In the latter case, if respiration does not resume after establishing an airway, then trauma victims are generally labeled with a black tag and not treated further (Hodgetts and Porter, 2004). However, in a chemical terrorism attack caused by a nerve agent, medical care should be actively provided to patients with cardiopulmonary or respiratory arrest recovery by such patients is clearly possible. 

For triage of the victims exposed to a nerve agent, victims with cardiopulmonary or respiratory arrest should be actively resuscitated while maximizing the available medical resources. 

Primary failure of respiration after exposure to toxicants other than nerve agents suggests a severity of exposure that requires intensive medical support at this point, a triage decision may be needed. The presence of wheezing indicates severe bronchospasm, which requires immediate therapy. The presence of dyspnea necessitates careful observation of the patient for at least 4 to 6 hours, until severe, potentially lethal respiratory damage can be reasonably excluded. 

It must be remembered that triage refers to priority for medical or surgical care, not priority for decontamination. All chemical casualties require decontamination. One might argue that a casualty exposed to vapor from a volatile agent, such as cyanide or phosgene, or from some of the volatile nerve agents does not need to be decontaminated. However, one can seldom be certain that in a situation in which vapor and liquid both exist, some liquid is not also present on the casualty. 

Some factors that might influence triage decisions at a unit-level MTF are discussed below. As noted above, most of these factors would not apply or would be ignored at a higher-level MTF that is relatively fully staffed and equipped, where the capability for medical care is not at a premium. Nerve Agents... 

In a casualty with mild-to-moderate intoxication from exposure to nerve agent vapor, administering the contents of MARK I kits can rapidly and completely reverse the nerve agent effects. Further triage decisions and medical care should focus on the conventional wound. 

Exampie of triage tag with spaoe to record nerve agent antidote injections. Photo Courtesy of Disaster Management Systems, ino., www.TriageTags.com. 

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