Agents Vesicants

Vesicant CW agents are compounds that cause blistering and skin necrosis and also affect other epithelial tissues, particularly the bronchial tree. Their action is different from corrosive agents and from thermal injury. Compounds in this class were developed as agents of CW as discussed in Chap. 2. 

HD is the most important of the vesicants and has been widely used in warfare in the twentieth century. Although the onset of signs and symptoms is insidious and has considerable latency, the action of the agent is rapid with skin penetration within 3 min. HD is persistent and therefore a danger to medical responders. It has a relatively low mortality but a high morbidity. 

There has been considerable research into the actions of HD. However, this has not so far produced any major advance in the management of HD exposure and no antidote exists. An overall understanding of the actions of HD is, therefore, useful for emergency medical responders but detailed knowledge of the research into the mode of action is not essential to the actions needed to manage casualties. 

EID penetrates rapidly into the skin by simple diffusion. There is significant penetration within 3 min and it is aided by humidity and warmth of the skin. Areas (such as the genitalia) with a thin epidermis are particularly vulnerable. 

HD is converted chemically from bis(2-chloroethyl)chloride (a simple substi-mted straight chain compound) by cycUsation into episulphonium ions which rapidly attack a wide range of chemical moieties such as thiols, amino and carboxylic groups. 

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Vesicant agents, such as mustard, require no special treatment once the bums have occurred. Copious washing is quite effective when used early for Hquid contamination of the eyes, and soap and water removes the Hquid agent from the skin. Bums resulting from mustard agent are treated like any other severe bum. The pulmonary injuries are treated symptomatically antibiotics are used only if indicated for the control of infection. 

Unprotected feedstock (e.g., hay or grain) should be destroyed. Leaves of forage vegetation could still retain sufficient vesicant agent to produce effects for several weeks post release, depending on the level of contamination and the weather conditions. 

Use only chemical protective clothing that has undergone material and construction performance testing against arsenic vesicant agents. Reported permeation rates may be affected by solvents, components, or impurities in munition grade or modified agents. 

Standard burials are acceptable when contamination levels are low enough to allow bodies to be handled without wearing additional protective equipment. Cremation may be required if remains cannot be completely decontaminated. Although arsenic vesicant agents are destroyed at the operating temperature of a commercial crematorium (i.e., above 1000°F), the initial heating phase may volatilize some of the agents and allow vapors to escape. Additionally, combustion will produce toxic and potentially volatile arsenic oxides. 

During World War I, pulmonary agents were sometimes mixed with various metal chlorides to produce a visible cloud. Agents were also sometimes mixed with arsenical vesicants (Agent Index C04) to increase their lethality. 

Many of these chemicals are similar to, but generally less toxic than, military chemical agents identified in other chapters of this book (e.g., nerve agents, vesicant agents, etc.). However, some of them are systemic poisons that act in ways that do not fit into one of the standard military classifications. 

MD Methyldichloroarsine, a type of blister/vesicant agent.. mg See MILLIGRAM. mg/Kg See MILLIGRAMS PER KILOGRAM. mg/M3 See MILLIGRAMS PER CUBIC METER... 

A review of the literature on experiments to assess possible chronic effects, especially mutagenic activity and carcinogenicity, of the irritant and vesicant agents reveals that these effects have not been studied systematically by current standards and techniques. 

As mentioned above, gas has been widely used and it is a powerful vesicant agent. In the form of vapor, it damages the respiratory tract. Eyes become temporarily blind and the skin in contact with the substance becomes inflammatory. The sweaty zones of skin are the most damaged as well as sensitive mucous membranes. If no treatment is applied, the cutaneous reaction provokes blisters full of liquid after 4-8 h. Spread in the form of particles, the gas penetrates the respiratory tract and destroys the mucous membranes with a respiration distress syndrome. Lungs suffer from emphysemae and edema due to the presence of fluids, which may cause a death similar to a drowning if the dose is too strong. 

Aerochemical Device for discharging many incendiary units simultaneously from a plane or for laying down a shower of a persistent vesicant agent from the air was devised by F. Short, USP 2,422,381(1948) CA 42,6117-18( 1948)... 

Automatic Chemical Agent Detection Alarm (ACADA-M22). The M22 is an advanced, pointsampling, chemical agent alarm system employing ion mobility spectrometry. It is designed to detect standard nerve and vesicant agents. 

Improved chemical agent point detection system (IPDS). The IPDS also employs ion mobility spectrometry and is an improved version of a point detection system. In addition to G and VX nerve agents, the IPDS is designed to detect vesicant agent vapors. Because it is a shipboard instrument, it will be much larger and will need more power than portable IMS devices. 

A.P. Watson and G.D. Griffin, Toxicity of vesicant agents scheduled for destruction by the chemical stockpile disposal program, Environ. Health Perspect., 98, 259-280 (1992). 

Rapid recognition of vesicating agents in an emergency is a key step to ensure rapid and effective care. Though many blister agents are similar in appearance, they may be differentiated based on their distinctive odor (Table 25.5). 

All of these vesicant agents act by producing direct irritation and have similar clinical presentations (see Figure 25.2). 

Hurst, C.G., Smith, W.J. (2008). Health effects of exposure to vesicant agents. In Chemical Warfare Agents, Chemistry, Pharmacology, Toxicology, and Therapeutics (J. Romano, Jr., B. Lukey, H. Salem, eds), pp. 293-312. CRC Press, Boca Raton, FL. 

NAS (1997). National Academy of Sciences, National Research Council, Committee on Toxicology, Subcommittee on Toxicity. Values for Selected Nerve and Vesicant Agents. National Academy Press, Washington, DC. 

Hurst, C.G., Smith, W.J. (2008). Health effects of exposure to vesicant agents. In Chemical Warfare Agents Chemistry,... 

The USA has disposed of stockpiles of sulfur mustard at sea. Fisherman or boaters who come across discarded canisters, leaky from sitting in salt water, unknowingly have become exposed. In treating these exposures, if the vesicant is pervasive, it is important to decontaminate in a prehospital setting, and have health care providers wear appropriate personal care protection. Latex gloves are not sufficient - butyl rubber is needed. Health care workers do not need to fear the patient s blisters, since these do not contain the vesicating agent. 

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