Mobile chemical detector (AP2C+SP4E) as an aid for medical decision making in the battlefield.

The combination of the AP2C unit with the SP4E kit composes a lightweight mobile detector of chemical warfare agents (CWA), such as nerve and mustard agents, with both vapor- and liquid-sampling capabilities. This apparatus was recently introduced into our military medical units as an aid for detection of CWA on casualties. Importantly, critical information regarding the applicability in the battlefield was absent. In view of the serious consequences that might follow a proclamation of CWA recognition in battlefield, a high false-positive rate positions the utilization of this apparatus as a medical decision tool in question. We have therefore conducted a field experiment to test the false-positive rate as well as analyze possible factors leading to false-positive readings with this device. The experiment was carried out before and after a 4-day army field exercise, using a standard AP2C device, a SP4E surface sampling kit, and a specially designed medical sampling kit for casualties, intended for medical teams. Soldiers were examined at rest, after mild exercise, and after 4 days in the field. The readings with AP2C alone were compared to the combination of AP2C and SP4E and to the medical sampling kit. Various body fluids served as negative controls. Remarkably, we found a false-positive rate of 57% at rest and after mild exercise, and an even higher rate of 64% after the 4-day field exercise with the AP2C detector alone, as compared to almost no false-positive readings with the combination of AP2C and SP4E. Strikingly, the medical sampling kit has yielded numerous false-positive readings, even in normal body fluids such as blood, urine, and saliva. We therefore see no place for using the medical sampling kit due to an unaccepted high rate of false-positive readings. Finally, we have designed an algorithm that uses the entire apparatus of AP2C and SP4E as a reliable validation tool for medical triage in the setting of exposure to nerve agents in the battlefield.

[Cyanides--treatment beneath the shade of terror].

Although the use of cyanides as warfare agents has not been documented since the Iran-Iraq war in the 1980s, there are rising fears of cyanide being used by terrorists. An Al-Qaeda terror plot to use cyanide gas in the London Underground was foiled in 2002. The threat of similar events becomes more imminent in light of the terror attacks in our country and worldwide, accompanied by statements and threats by fundamentalist leaders to employ chemical weapons. Therefore, mass-intoxication with cyanides is not merely a hypothetical scenario. The treatment of cyanide poisoning is under constant evaluation and there is no international consensus on the subject. The medical treatment of victims at the scene and in hospitals should be rapid and efficient. Current treatment dictates establishing an intravenous line and a slow rate of administration of antidotes. Both demands are not feasible in this specific mass casualty event. The clinical signs of cyanide poisoning are complex, variable and not necessarily obvious for the medical team. There is great interest in reconsidering the existing treatment protocols for cyanide intoxication in light of current research. This review describes the mechanisms of cyanide toxicity, clinical signs of exposure, and current treatment protocols in use worldwide. On the basis of this evidence we suggest a medical treatment protocol for a mass casualty event caused by cyanide.

Civilian adult self injections of atropine-trimedoxime (TMB4) auto-injectors.

INTRODUCTION: The clinical effects of self injections of atropine-trimedoxime auto-injectors distributed to the civilian population as a field antidote for nerve agent attack were assessed. METHODS: Data on self injections by adults (> or = 18 years) were collected from the Israel Poison Information Center and a hospital Emergency Department's records during a 2-year period. The data included demographics, time interval from injection, type of auto-injector, clinical manifestations and atropinization score. RESULTS: Sixty-five patients, all with unintentional self injections, were reported. Systemic atropine effects were observed in 24 patients, but no severe atropinization. The atropinization score was significantly higher in the 2 mg atropine dose group than in the two lower dose groups, which were in the normal range. No specific adverse effects attributable to trimedoxime were observed. Intravenous fluids and physostigmine were not required. CONCLUSION: Only mild reactions were observed following self-injection of atropine trimedoxime auto-injectors in adults, attesting to their relative safety under these conditions.

OP or not OP: the medical challenge at the chemical terrorism scene.

Since the 1995 Tokyo subway sarin attack, terrorist attacks involving weapons of mass destruction or other industrial chemicals present worldwide security and health concerns. On-scene medical triage and treatment in such events is crucial to save as many lives as possible and minimize the deleterious effects of the toxic agent involved. Since there are many chemicals that can be used as potential terrorist weapons, the medical challenge for the emergency medical services (EMS) is a combination of: (1) recognizing that a chemical terrorist attack (non-conventional) has occurred; and (2) identifying the toxic agent followed by proper antidotal treatment. The latter must be done as quickly as possible, preferably on-scene. The most valuable decision at this stage should be whether the agent is organophosphate (OP) or not OP, based on clinical findings observed by pre-trained, first responders. This decision is crucial, since only OP intoxication has readily available, rapidly acting, onscene, specific agents such as atropine and one of the oximes, preferably administered using autoinjectors. Due to the lack of a specific antidote, exposure to other agents (such as industrial chemicals, e.g., chlorine, bromide, or ammonia) should be treated on-scene symptomatically with non-specific measures, such as decontamination and supportive treatment. This paper proposes an algorithm as a cognitive framework for the medical teams on-scene. This algorithm should be part of the medical team's training for preparedness for chemical terrorist attacks, and the team should be trained to use it in drills. Implementing this path of thinking should improve the medical outcome of such an event.

[Medical management in the chemical terrorism scene].

The Tokyo subway sarin attack in March 1995 demonstrated the importance of preparedness toward a chemical terrorist attack. Emergency medical teams on the scene are valuable, beside the medical treatment of casualties, in the cognition of toxicant involvement and later in the recognition of the specific toxidrome involved. The chemical terrorism scene is a contaminated area; therefore, first responders have to be protected from both percutaneous and inhalational exposure to toxic materials. This protection is also against secondary evaporation (gas-off) from contaminated casualty, hence the importance of disrobing casualties on the scene as soon as possible. Once the recognition of toxicological involvement have been made, the next crucial decision is whether the clinical toxidrome is of cholinergic toxicity (e.g. organophosphate or carbamate intoxication) in which there are automatic injectors for treatment available on the scene, or any other toxidrome (such as irritation or vesicants) in which, beside general measures, like oxygen delivery and airway support, there is not a specific antidotal treatment on the scene. The clinical detection and identification of the chemical toxidrome involved is of utmost importance since it promotes the antidotal treatment quickly and efficiently. The key to the medical management of such events is based on decisions that have to be taken as soon as possible according to the clinical judgment of medical teams on the scene.

Pharmacologic prophylaxis against nerve agent poisoning.

Nerve agent poisoning is characterized by the rapid progression of toxic signs, including hypersecretions, tremor, convulsions and profound brain damage. In the political arena of today's world, the threat of nerve agent use against military troops has prompted armies to search for prophylactic protection. The two main strategies for prophylaxis include biological scavengers that can bind or cleave nerve agents before they react with acetylcholinesterase, and antidotes as prophylactic treatment. Pyridostigmine is the current pretreatment for nerve agent poisoning and is in use by most of the armed forces in Western countries. However, since pyridostigmine barely crosses the blood-brain barrier it provides no protection against nerve agent-induced central injury. Pyridostigmine is ineffective when administered without post-exposure treatment adjuncts. Therefore, other directions for prophylactic treatment should be explored. These include combinations of carbamates (reversible AChE inhibitors) and central anticholinergics or NMDA receptor antagonists, benzodiazepines or partial agonists for benzodiazepine receptor, and other central AChE inhibitors approved for Alzheimer's disease. The transdermal route is an alternative way for delivering the prophylactic agent. Administration of prophylaxis can be extended also for civilian use during wartime.