Use of a Nerve Agent Antidote-Dosing Tool for Mass Casualty Incident Emergency Preparedness

Abstract

Objective:

Nerve agent attacks pose a serious threat worldwide and ensuring optimal readiness is essential to management. We review a mass casualty incident (MCI) drill in a busy urban New York City Emergency Department incorporating an antidote-dosing tool.

Methods:

Emergency Management and Preparedness planned an MCI drill involving a nerve agent exposure and engaged the pharmacy department to participate on a more comprehensive level. The clinical pharmacist prepared a treatment tool with antidote dosing recommendations to distribute to team members participating in the drill.

Results:

During the launch of the exercise, all clinicians involved reviewed the antidote-dosing tool with the pharmacy team members. Because of the ease of use, limited time was necessary to review the dosing tool before the start of the exercise. After the exercise, feedback regarding the use of the tool was very positive and participants appreciated the tool for use in a theoretical emergency that they have had limited experience managing.

Conclusions:

Optimizing team preparedness with accessible and practical dosing tools may be a helpful addition to emergency preparedness for chemical and biological events with the potential for many casualties.

Acetylcholinesterase inhibitors (AChEIs) are xenobiotics that bind acetylcholinesterase, the enzyme responsible for breakdown of acetylcholine. ¹ AChEIs chemical groups are classified as quaternary alcohols, carbamates, and organophosphates (OPs), with the latter having the most potential for human harm. With industrial exposures, intentional overdoses, or as a chemical weapon, AChEIs can lead to an overwhelming accumulation of acetylcholine in the peripheral and central nervous systems. ²

Since World War I, there has been a significant expansion in the use of the subcategory of OPs referred to as nerve agents for the purpose of chemical warfare. Nerve agents began to be mass-produced as chemical weapons by Nazi Germany during World War II, and since then, second-, third-, and fourth-generation agents have been developed. ³ Fourth-generation agents are the most potent nerve agents known to date, and are sometimes referred to as Novichoks (“newcomer” in Russian).

The use of a nerve agent in a chemical attack, although rare, has the potential for catastrophic morbidity and mortality, as seen with the 1995 Tokyo sarin attack that injured over 5000 people. ⁴ The CHEMPACK program was created as part of the Strategic National Stockpile and was designed for the forward placement of the necessary antidotes in the setting of a potential large-scale nerve agent attack in the United States. ⁵ The possibility of terror attacks, particularly in New York City (NYC), proves the need for defense measures against chemical, biological, radiological, and nuclear (CBRN) agents. Since the 9/11 terror attacks occurred in NYC in 2001, NYC hospitals have prioritized CBRN planning across several sectors including law enforcement, fire department, emergency medical services, public health, and health-care stakeholders. Additionally, after several recent reports of poisoning using fourth-generation agents, health-care facilities renewed their interest in becoming better prepared for nerve agent exposure response. ³

Because of the infrequency of CBRN events, preparation is critical and an ongoing challenge for health-care and emergency systems to ensure proper response to a mass casualty incident (MCI) involving hazardous agents. ^4,6 One of the most well prepared countries for CBRN response due to previous and ongoing conflicts is Israel. ² In a review of MCI emergency preparedness in 23 acute care hospitals in Israel, a high rate of staff knowledge was observed for responding to rare events such as toxicological and biological attacks. ⁶ This was despite most health-care workers in the system not having practical experience responding to such events. The review noted that each emergency department (ED) is supplied with information sheets with the management for each type of hazard immediately accessible to them to avoid clinicians having to recall from memory or spend time finding resources.

Effective hospital disaster preparedness should engage multiple stakeholders along with ancillary departments and external agencies. The pharmacy department may be an underused resource when engaging in MCI planning. ⁷ In addition to ensuring proper antidote stocking, storage, and dispensing in the event of an occurrence, pharmacy resources can be accessed to supplement clinical support for antidote management strategies. Because of the rarity of such an event, many institutions may not have a standardized dosing tool for OP incident management.

Methods

Our institution is a busy, 450-bed, academic Level 1 Trauma Center in NYC accustomed to unpredictable patient surges and multiple triage events including motor vehicle accidents, gunshot wounds, and multi-dwelling fires. Due to the urban location of the hospital, as well as proximity of the surrounding industrial areas, leadership has prioritized chemical event planning.

In the planning stage for a chemical incident MCI drill, it was proposed that medical staff would benefit from having a succinct antidote-dosing tool to rapidly disseminate during the drill. While the Centers for Disease Control and Prevention (CDC) maintains a job aid website for initial emergency department treatment, the algorithm does not differentiate between mild/moderate and severe manifestations, or provide detailed administration instructions and guidance. ⁸ Moreover, in a true nerve agent attack, it is reasonable to anticipate that medical staff may be overwhelmed with the additional task of locating an antidote dosing guide, while attempting to manage an unpredictable patient volume and acuity level under extreme psychological stress. Furthermore, in a catastrophic attack, Internet or online resources may be inaccessible. In collaboration with the full-scale exercise (FSE) planning team, the clinical pharmacist developed an antidote-dosing guide to use for the planned MCI chemical agent drill.

The dosing guide was created to be a 2-sided 1-page tool (Figure 1). Information provided on the first side included examples of nerve agents, personal protective equipment warnings, and pharmacy contact numbers. The tool included antidote-related pharmacotherapy information such as mechanisms of action, concentrations supplied, and administration instructions and goals of therapy for the primary used antidotes and therapies including atropine, pralidoxime, and benzodiazepines.

Figure 1. Nerve Agent Antidote-Dosing Tool

The second page was modeled after dosing guidance provided by the NIH (National Institutes of Health) and CDC, with additional therapeutic considerations added to the dosing guide. ^2,8–10 Treatment recommendations were stratified by level of toxicity and symptomology, as well as by age and weight. The pharmacy department maintains a 24/7 decentralized pharmacy satellite in the ED. Physical copies of the dosing guide were kept with stocked antidotes in the ED satellite, and as a supplement to the MCI Response Toolkit.

Antidote supplies were reviewed and doses calculated for an estimated initial patient influx to treat such an incident. Based off this review, our pharmacy department optimized par levels of stored antidotes to ensure adequate amounts for emergent treatment before the receipt of a theoretical authorized CHEMPACK distribution.

This exercise did not involve patient subjects and was exempt from Institutional Review Board (IRB) review.

Results

Per the internal MCI standard drill protocol, an interdisciplinary pre-event huddle was completed, where all required personnel received known and pertinent casualty information. Delineation of clinical, nursing, pharmacy, security, and other leadership roles were discussed. Clinical pharmacists and other members of the pharmacy team were deployed to the ED for the drill to serve as subject matter experts and facilitate medication dosing, preparation, and pharmacotherapy questions. All clinicians, nursing, and pharmacy team members reviewed and discussed the OP nerve agent tool with the developers of the dosing tool in advance of patient arrival to determine theoretical treatment plans for exercise patients. Because of the self-explanatory nature of the guide, limited training time was necessary for team members to familiarize themselves with the treatment algorithm. To assess the key objectives of the exercise, evaluators were strategically placed at the entrance to the emergency department, the pharmacy, and within treatment areas.

After the drill, a debriefing was performed and participants were queried for feedback, including specifics of using the nerve agent antidote tool. Clinician and nursing feedback specified that having a concise algorithmic tool expedited antidote dosing and provided medication administration clarity, as most were unfamiliar with management. After the exercise, some modifications were made to the antidote dosing tool, including clarification of dilution and administration instructions and highlighting mg/kg for pediatric weight-based dosing.

Limitations

The limitation of this report is that it was performed at a single center with a small cohort of staff in a single exercise. No comparison of the outcome of this MCI drill was made to any previous drills without the resource of an antidote-dosing tool. Feedback on using the dosing tool was only received from the team members participating in this MCI drill. Although an MCI drill is designed to mimic real life experiences, a true catastrophic MCI can be unpredictable and may transpire differently.

Discussion and Conclusions

To our knowledge, this is the only publication detailing an MCI drill for nerve agent chemical exposure using an antidote-dosing tool for adult and pediatric patients. In a survey by Madsen and Greenberg of 89 ED directors in 12 highly populated US cities, only 18.3% of respondents reported being very confident that their training for MCIs had prepared their departments to respond to a chemical attack. ⁵ This survey also highlighted major deficiencies in knowledge regarding antidote stocking and treatment capabilities for a theoretical nerve agent incident.

Incorporating dosing tools has the potential to empower providers to efficiently make treatment determinations during a potential catastrophic event when time, experience, and resources are limited. All participating providers in our MCI drill used the dosing guide while treating exercise patients, and a positive response was reported in anonymous post exercise surveys.

To best prepare for a nerve agent MCI, it is imperative that the ED work together with their disaster response teams and pharmacy management to establish antidote supply par levels and plans for distribution, as well as consider engaging clinical pharmacists to create an easy-to-use management guide. Maintaining such a guide in addition to functioning as a dosing tool for provider decision support, allows the pharmacy department to ensure specific drugs, available concentrations, and par levels are regularly updated on the institution level. In general, MCI drills focus on key operational competencies (eg, triage) and often do not provide a strong focus on methods for clinical treatment and acute stabilization of patients. With the threat of nerve agent attacks an ongoing concern, it is imperative to augment health-care institutional emergency preparedness and address the clinical knowledge and operational gaps for CBRN events by developing tools to maximize efficiency in times of crisis.