Emergency Medical Services-CE27

The patient is placed on high-flow Oxygen via non-rebreather mask and his SpO2 improves to 96%.  Albuterol 5mg (6mL) via neb is also initiated. On assessment, the patient has diffuse wheezing and excessive salivation, making it difficult for him to breath. He is in a tripod position. He appears very anxious and confused. You note that he has pinpoint pupils.

This patient’s presentation is most consistent with a cholinergic toxidrome.  Nerve agents and in this case, organophosphate pesticides, cause inhibition of the enzyme acetylcholinesterase which results in extra acetylcholine availability at receptors throughout the body.  Acetylcholine binds to nicotinic and muscarinic receptors.  Overstimulation of the nicotinic receptors at the neuromuscular junction can result in muscle jerking and eventual paralysis.  Binding to the muscarinic receptors results in both sympathetic (e.g. excessive diaphoresis, tachycardia) and parasympathetic effects (e.g bradycardia, bronchorrhea, bronchospasm, urination, and defecation). Common symptoms of the cholinergic toxidrome are summarized with the mnemonic DUMBELS:

D – Defecation/diaphoresis

U – Urination

M – Miosis (pinpoint pupils)

B – Bronchospasm/bronchorrhea

E – Emesis  (vomiting)

L – Lacrimation (excessive tearing)

S – Salivation

Additional symptoms can include anxiety, confusion, drowsiness, hallucinations, seizures, respiratory depression and eventually respiratory failure due to muscle paralysis as symptoms progress.

Treatment for organophosphate exposure is atropine.  Atropine works by outcompeting the excess acetylcholine at muscarinic receptors.  Administration will result in drying of the excess saliva, decreased bowel sounds, resolution of bronchospasm, and treatment of bradycardia if present, however large doses of atropine may be required for these effects.  Atropine will not impact nicotinic receptor effects, so patients must still be monitored for respiratory failure due to paralysis even if they respond to atropine. Large cumulative doses of atropine may be required.  The goal of atropine therapy is to improve cardiorespiratory status, which may require repeat dosing until airway secretions, bronchospasm, and bradycardia resolve.

The insect spray concentrate is identified as an organophosphate.  The patient’s symptoms are also clinically recognized as being consistent with organophosphate exposure.  Atropine 2mg (20mL) IV is administered.  The patient’s level of consciousness decreases, and he has persistent airway secretions.  Impending respiratory failure is noted when paramedics intubate.  Significant airway secretions are suctioned during and after intubation.  Paramedics administer atropine every 5 minutes en route to the hospital per TP-1240, HAZMAT.

The CHEMPACK program is generally intended for large scale nerve agent attacks where a stockpile of treatments is required to have adequate access to required antidotes for cholinergic toxidrome.  However, there have been historic cases in California, where the CHEMPACK program was activated when a hospital ran out of atropine caring for a patient with cholinergic toxidrome due to organophosphate toxicity.  In this situation, activation of the CHEMPACK program can be authorized because the treatments are medically necessary to save human life.

The CHEMPACK program was created by the Centers for Disease Control (CDC) and designed to place nerve agent antidotes in communities all over the country to support a quick response to a nerve agent attack. The CHEMPACK program is a component of the Strategic National Stockpile (SNS). Each CHEMPACK contains auto-injector antidote kits, atropine, 2-Pralidoxime, sterile water for injection, and Diazepam/Midazolam for seizure management. There are two types of CHEMPACK containers:

• EMS CHEMPACK: Designed for prehospital medical providers, and the antidotes contained in the EMS CHEMPACK are mostly auto-injectors for speed and ease of use.

• Hospital CHEMPACK: Designed for hospital medical staff, and the antidotes contained in the hospital CHEMPACK are primarily multi-dose vials.

In the event that a CHEMPACK needs to be deployed, one can be requested by calling the Medical Alert Center as described in Ref. No. 1108, CHEMPACK Deployment for Nerve Agent Release.

EMS transports the patient to the MAR where additional atropine and supportive care are provided to the patient.  Large quantities of atropine were required to reverse the effects of the organophosphate ingestion.  The hospital had adequate supplies of atropine to manage this patient and did not require CHEMPACK resources, though resources could have been requested if not otherwise accessible and needed to save human life.  Following medical treatment, the patient was evaluated and treated by psychiatry.

1. In HAZMAT scenarios, clinician use of appropriate PPE and prioritizing patient decontamination are needed to prevent secondary contamination.
2. Cholinergic toxidrome can be a result of exposure to a nerve agent or an organophosphate.  Symptoms are described in the DUMBELS mnemonic.
3. Organophosphate toxicity results from inhibition of the enzyme acetylcholinesterase, resulting in excess acetylcholine to bind to nicotinic and muscarinic receptors.  The muscarinic effects can be reversed with atropine, though large amounts may be required.
4. The CHEMPACK program is a component of the Strategic National Stockpile.  CHEMPACK deployment is intended for nerve agent attacks with a large scale of victims, however, if deployment of the asset is required because antidotes are needed to save human life, a CHEMPACK can be requested and deployed.