All of us in the fire service are aware of the need for rapid administration of antidote when organophosphorous poisoning occurs. Organophosphates are the basis of many insecticides, herbicides and nerve gases.
Our training for weapons of mass destruction (WMD) has included the use of, first, the Mark I Kit, and, subsequently, the upgrade to the DuoDote Auto-Injector. A recent study published in the August issue of the Journal of Emergency Medicine showed that using the DuoDote Auto-Injector cut the antidote administration time in half.
The study, which was conducted by St. Louis University, compared the use of the Mark I Kit, which contains two separate auto-injectors of atropine and pralidoxime chloride, with a single needle and syringe injection of atropine and also with the Antidote Treatment Nerve Agent Auto-Injector (ATNAA), the military version of the DuoDote Auto-Injector. The ATNAA, like the DuoDote Auto-Injector, is a single-needled, pre-filled, dual-chambered auto-injector containing both atropine and pralidoxime chloride.
In this randomized, un-blinded study, researchers compared the time required to administer the antidote using all three methods and devices in different conditions. They concluded that the use of auto-injectors shortened the time required to administer the atropine and pralidoxime antidotes. Further, they found that the use of the single auto-injector ATNAA took less than half the time to administer than the dual auto-injector Mark I. They also found no difference in delivery times between the Mark I and needle and syringe administration.
Minutes To Administer
Chemical nerve agents and organophosphorous insecticides bind to enzymes in the body and block their activity, causing an excessive build up of acetylcholine, which is a neurotransmitter that stimulates our nerve pathways. The result is impaired respiratory, gastrointestinal, muscular and vascular function.
Once exposed, we may have only minutes to administer the antidote. If untreated, paralysis, suffocation and death can result. The atropine in the antidote blocks the effect of the acetylcholine by reducing secretions in the airway and respiratory passages and relieving airway constriction while increasing the heart rate. The pralidoxime chloride reactivates acetylcholinesterase, restoring its purpose of moderating acetylcholine.
Like the ATNAA, the DuoDote Auto-Injector delivers 2.1mg/0.7 mL of atropine and 600mg/2mL of pralidoxime chloride in a single injection. It provides a compact, quick and efficient delivery through clothing if necessary. It requires no preparation and received FDA approval in 2006. The DuoDote Auto-Injector is accessible through federal homeland security and emergency preparedness grants.
Speed is essential when providing antidote to poisoned responders, and the ease of use and rapid delivery of DuoDote responds to this need. As with any medication, it should only be used when there is a clear indication for its use.
It is important to note that while there are no absolute contraindications to the use of the DuoDote Auto-Injector, it should not be used unless exposure is confirmed. If exposure is not certain, caution should be exercised when considering use on patients with histories of heart disease, severe narrow angle glaucoma, pyloric stenosis, prostatic hypertrophy, significant renal insufficiency, chronic pulmonary disease or hypersensitivity to any component of the device.
Risk Of Exposure
While regional WMD response planning includes delivery of antidotes for organophosphorous to responders when exposed during intentional terrorist type events, daily exposures present a more common danger. It is unlikely that most of us will be exposed to this type of exposure in an intentional event, but there is a very real risk of exposure in our daily activities as we respond to events including the manufacture, storage, transportation or use of the hazardous chemicals.
Recent enhancements in protective clothing have helped to reduce risk, but the lessons learned from military operations, WMD and terrorist response should be applied to our daily practice. While training, equipment and medications are developed to counter WMD, the best benefit may be how we apply these resources to the more likely exposures in unintentional events in our communities.
Editor’s Note: Will Chapleau, who has more than 30 years of EMS experience, is the Advanced Trauma Life Support (ATLS) program manager for the American College of Surgeons. He is the former chief of the Chicago Heights (Ill.) Fire Department, has served since 1996 as the chairperson for the Prehospital Trauma Life Support (PHTLS) program of the National Association of Emergency Medical Technicians and has been a member of its international faculty since 1984. He is a board member of the National Association of EMS Educators.