You are in: eMedicine Specialties > Emergency Medicine > WARFARE - CHEMICAL, BIOLOGICAL, RADIOLOGICAL, NUCLEAR AND EXPLOSIVES CBRNE - Chemical DecontaminationArticle Last Updated: Mar 29, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Liudvikas Jagminas, MD, Physician-in-Chief of Emergency Medicine, Associate Professor of Emergency Medicine, Brown Medical School, Memorial Hospital of Rhode Island Liudvikas Jagminas is a member of the following medical societies: American College of Emergency Physicians, American College of Surgeons, American Medical Association, American Trauma Society, Rhode Island Medical Society, and Society for Academic Emergency Medicine Editors: Mark Keim, MD, Director, Emergency and Disaster Public Health Sciences, Adjunct Assistant Professor, Department of Emergency Medicine, Emory University, National Center for Environmental Health, Centers for Disease Control and Prevention; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital; John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center; Robert G Darling, MD, FACEP, Clinical Assistant Professor of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Director, Center for Disaster and Humanitarian Assistance Medicine Author and Editor Disclosure Synonyms and related keywords: chemical warfare agents, hazardous materials, decon, chemical decontamination, chemical disasters, chemical exposure, decontamination management INTRODUCTIONSection 2 of 10
  Emergency departments (EDs) and emergency medical services (EMS) are responsible for managing potential chemical disasters, whether they result from industrial accidents or terrorist activities. In recognition of this responsibility, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) and the Occupational Safety and Health Administration (OSHA) require EDs to prepare for hazardous material incidents. In treating patients with chemical exposures, decontamination is of primary importance provided the patient does not require immediate life-saving interventions. Any plan must include contingencies for contamination sources within the hospital and for ED evacuation. The determination of a workable hazardous materials plan requires careful thought and often professional input from medical toxicologists, hazardous materials teams, and industrial hygiene and safety officers. Using a patient decontamination plan implemented without specific adaptation to the hospital and without practice can result in undesirable outcomes. Legal requirements apply to hospital-based decontamination. All EDs incorporated in an emergency response plan for hazardous materials incidents must meet OSHA requirements (29 CFR 1910.120[q]) for both staff training and response to hazardous materials, because they likely will be presented with a chemically exposed patient who has not been decontaminated at the scene. Under these regulations, emergency medical personnel who may decontaminate victims exposed to a hazardous substance should be trained at a minimum to the first-responder operational level. For response to an unknown hazard, OSHA regulations require Level B protection, which includes a positive-pressure self-contained breathing apparatus and splash-protective chemical-resistant clothing. PURPOSE OF CHEMICAL DECONTAMINATIONSection 3 of 10
Chemical decontamination has 2 primary goals. Firstly, decontamination helps prevent further harm to the patient from the chemical exposure. Methods of patient decontamination include chemical dilution and chemical inactivation. Secondly, decontamination helps protect healthcare providers and maintains the viability of the ED as a treatment center. Mismanagement may result in illness in healthcare providers and contamination of the ED; severe ED contamination may necessitate departmental closure, which is potentially catastrophic in a mass casualty incident. RECOGNIZING A CHEMICAL CONTAMINATIONSection 4 of 10
Before chemical decontamination can occur, chemical contamination must be recognized. The most important tool for assessing a patient for chemical exposure is a careful history. Continue to consider chemical exposures in the differential diagnosis for any mass casualty incident in which multiple ill persons with similar clinical complaints (point-source exposure) seek treatment at about the same time or in persons who are exposed to common ventilation systems or unusual patterns of death or illness. PERSONAL PROTECTIVE EQUIPMENTSection 5 of 10
Personal protective equipment (PPE) is the clothing and respiratory gear designed to protect the health care provider while he or she is caring for the contaminated patient (see CBRNE - Personal Protective Equipment). The minimum protective equipment required by OSHA regulations for healthcare providers caring for patients contaminated with an unknown substance include chemical-resistant suits that guard against splash exposures and positive-pressure full-faced respirators. Using this equipment requires specialized training; therefore, train appropriate personnel in the use of this equipment before they need to use it. PPE is divided into 3 levels. Level A PPE is required in the area of chemical release if dangerous exposure levels potentially are present. A Level A suit is fully encapsulated and chemically resistant to both liquid and vapor exposures. Since this suit is fully encapsulated, it requires self-contained breathing apparatus. The level of protection typically provided to those involved in the decontamination procedure is a Level B suit. This suit requires a full-faced positive-pressure respirator, is chemically resistant, and provides protection against splash exposures. Use Level C protection when the chemical hazard is known, the concentration is at nontoxic levels, and ambient air oxygen levels are at or above 21% of atmospheric levels. Level C protection involves chemical-resistant clothing and air-purifying respirators to filter airborne contaminants. For excellent patient education resources, visit eMedicine's Bioterrorism and Warfare Center. Also, see eMedicine's patient education articles Personal Protective Equipment and Chemical Warfare. PATIENT DECONTAMINATIONSection 6 of 10
ED staff has the following 3 primary goals in treating a patient who has been exposed to a hazardous material and may be contaminated or who has not undergone adequate decontamination before arrival at the hospital: (1) isolate the chemical contamination; (2) appropriately decontaminate and treat the patient(s) while protecting hospital staff, other patients, and visitors; and (3) reestablish normal service as quickly as possible.
General principles The hot zone, or immediate isolation zone, is the area of immediate contamination. Entry into a hot zone requires special technique and equipment. It is imperative that the hot zone be isolated immediately and entry restricted to avoid additional unnecessary casualties. Chemical agents are especially likely to spread downwind, creating an at-risk area, protective action zone, which is potentially amenable to evacuation. Notably, dispersion dynamics are such that "downwind" is rarely a straight line and is more likely to be an expanding plume. Gases spread differently in the atmosphere during day and night. Meteorologic conditions, population concentrations, communication capabilities, the specific agent and amount released, and evacuation routes must be identified and are factors in decisions to either evacuate or shelter in place. The hot zone must be approached from an upwind direction, an area that is also a potential evacuation and treatment area. The indicators of nerve gas release will resemble the consequences of other weapons of mass destruction (WMD), such as immediate casualties of similar presentation; a suspicious site characterized either by a dispersal device, unexplained gaseous clouds, vapors, or odors; or an absence of animal, bird, or insect life. Alternatively, there may be intelligence based on reports, remote detection, or point use chemical detectors. Victims must be identified, decontaminated, and evacuated, and general and specific therapy administered as rapidly and efficiently as possible. Considerations include triage and prioritization, communication with a central command center, and identification of all potential sources of important resources such as medications, monitors, and life-support equipment. For example, local supplies of drugs such as atropine, amyl nitrite, and thiosulfate will be exhausted rapidly in a mass casualty scenario, so alternative supplies need to be identified and efficiently procured. Casualties will also be individuals who sustained secondary trauma during exposure to chemical agents, falls and blunt trauma, motor vehicle injuries, burns, or aggravation of preexisting comorbidities such as chronic lung disease and myocardial ischemia. These patients will need to be treated according to established medical principles, including the ABCDs of acute care. Treatment area When responding to a disaster involving hazardous materials and weapons of mass destruction, it is critical that the treatment area be at least 300 yards upwind of the contaminated area.
Special considerations for the chemical warfare patient The best universal liquid decontamination agent for chemical warfare agents (CWAs) is 0.5% hypochlorite solution. It is prepared easily by diluting household bleach to one-tenth strength (ie, 9 parts water or saline to 1 part bleach). Hypochlorite solution works through physical removal and oxidation and/or hydrolysis of the agent; water does this at a much slower rate. Hypochlorite solutions are for use on the skin and soft-tissue injuries, including open lacerations. Do not use it in penetrating abdominal wounds (leads to development of peritoneal adhesions), in the eye (leads to corneal opacities), in open chest wounds, or in open brain or spinal cord injuries (effects unknown). Irrigate these areas with copious amounts of sterile saline solution. After using hypochlorite solution on either the skin or soft-tissue wounds, subsequently irrigate these areas with sterile saline solution. The military also has access to a universal dry decontaminant known as M291 resin, which is available as pads packaged in small individual packets. M291 resin is a dry black carbonaceous material that decontaminates by absorption and physical removal of the CWA from the victim. M291 resin is used for spot decontamination of skin exposed to CWAs. Organization of the military treatment area in chemical warfare A full discussion of the military medical team response to a chemical warfare attack is beyond the scope of this article. Please refer to Medical NBC web site for access to the Textbook of Military Medicine for a complete discussion of this area (http://www.nbc-med.org). A basic understanding of the structure of the military's medical treatment facility is important for civilian health care providers, since they most likely will be working with the military in the event of a chemical warfare incident. The military medical treatment facility is divided into dirty and clean sides. The demarcation of the sides is known as the hotline. The concept of the hotline is to keep all contaminated equipment, personnel, and casualties out of the clean side until decontamination is completed. The dirty side consists of a triage station, emergency treatment station, and a decontamination area. The triage station is the single entry point into the medical treatment facility. If the patient has an emergent medical condition that requires immediate medical intervention before decontamination, the patient is sent from triage to the emergency treatment station. The emergency treatment station is equipped to handle contaminated patients with emergent medical issues and stabilize them for either decontamination at the medical treatment facility or dirty evacuation to another facility for a higher level of care. The decontamination area is divided into ambulatory and nonambulatory patient decontamination areas. The clean side consists of part of the decontamination area and the clean treatment area. The hotline extends through the decontamination area. Patients are decontaminated on the dirty side and are brought to the hotline nude except for their PPE mask. These patients are transferred across the line to a team on the clean side of decontamination area. The clean side decontamination team then brings patients into the clean treatment area. The clean treatment area is located 30-60 meters upwind of the dirty side. The clean side decontamination team removes the patient's mask prior to transferring the patient to the clean treatment area. In the clean treatment area, the patient can be treated definitively or transferred to another facility if needed. SUPPORTIVE CARESection 7 of 10
Saving lives always depends on ensuring the ABCs: adequate airway, ventilation, and circulation. Greater contamination or exposure more likely results in victims who require early intubation and ventilation. Conversely, adequate ventilation may be impossible because of the intense muscarinic effects of certain nerve gas exposures (copious airway secretions, bronchoconstriction). In this situation, administer atropine before initiating other measures. In some patients, large quantities of atropine may be required, rapidly depleting hospital supplies. Administering succinylcholine to assist intubation is relatively contraindicated, since nerve agents prolong the drug's paralytic effects. Benzodiazepines are the mainstays in seizure treatment. Liberal doses are required; titrate to effect. Termination of seizure activity may reflect onset of flaccid paralysis from the nerve agent rather than adequacy of antiseizure therapy. A bedside electroencephalograph (EEG) may be required to assess ongoing seizure activity. Animal data suggest that routine administration of diazepam reduces the incidence of seizures and decreases severity of pathologic brain injury following nerve agent exposure. CWAs are a diverse group of extremely hazardous materials. Emergency physicians must be familiar with the pathophysiology and various clinical presentations produced by CWAs and the principles and practices of appropriate medical management. Since deployment of CWAs also places emergency care providers at serious risk of exposure, emergency physicians must be familiar with the different levels of PPE, appropriate use, and decontamination procedures. CWAs, as potential weapons of mass destruction with the capability of causing a catastrophic medical disaster, easily may overwhelm any healthcare system. Since civilian victims exposed to CWAs are likely to flee to the nearest hospital, emergency physicians provide the first line of treatment and must prepare their EDs for the treatment of persons exposed to CWAs. IDENTIFYING THE CHEMICAL AND OBTAINING EXPERT ADVICESection 8 of 10
Ideally, a hazardous materials team at the scene will be able to provide assistance regarding the specifics of the exposure and the potential treatment. A local poison control center also may be able to provide assistance. The Chemical Manufacturers Association provides 24-hour assistance in the specifics of treating a particular chemical exposure; it can be reached at (800) 424-9300. The Domestic Preparedness Chem/Bio Helpline can be reached at (410) 436-4484. Online information is available at Centers for Disease Control and Prevention. DECIDING TO EVACUATE THE EMERGENCY DEPARTMENTSection 9 of 10
Evacuation of the ED rarely is indicated. In most situations, isolation of the contamination is all that is required. Consider evacuation of the ED in the following situations:
If symptoms start to occur outside of the isolation area or the situation requires urgent decision making without time to identify the contaminant, consider evacuation. Odor does not predict toxicity reliably. REFERENCESSection 10 of 10
CBRNE - Chemical Decontamination excerpt Article Last Updated: Mar 29, 2006 |
