Understanding Poisoning and Overdose in EMS
Poisoning accounts for a significant percentage of EMS calls, ranging from accidental ingestions in pediatric patients to intentional overdoses in adults. The American Association of Poison Control Centers reports over two million human poison exposures annually. As an EMT, your ability to rapidly identify the substance involved, recognize the clinical presentation, and initiate appropriate treatment can be lifesaving.
Routes of exposure include ingestion (most common), inhalation, absorption through the skin, and injection. The route of exposure affects both the onset of symptoms and the appropriate decontamination strategy. Always consider your own safety first; some substances that poisoned the patient can also harm rescuers through secondary exposure.
Recognizing Common Toxidromes
A toxidrome is a constellation of signs and symptoms associated with a particular class of substance. Learning to recognize toxidromes allows you to identify the likely substance even when the patient cannot provide a history. The major toxidromes include:
- Opioid toxidrome: Respiratory depression, pinpoint pupils (miosis), altered mental status, hypotension, bradycardia. Common substances include heroin, fentanyl, oxycodone, and morphine.
- Sympathomimetic toxidrome: Tachycardia, hypertension, hyperthermia, dilated pupils (mydriasis), agitation, diaphoresis. Common substances include cocaine, methamphetamine, and bath salts.
- Anticholinergic toxidrome: "Hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter." Tachycardia, dry skin, flushed, dilated pupils, altered mental status, urinary retention.
- Cholinergic toxidrome (SLUDGE/DUMBELS): Salivation, lacrimation, urination, defecation, GI distress, emesis. Also bradycardia, miosis, and bronchospasm. Seen with organophosphate and nerve agent exposure.
Opioid Overdose and Naloxone
Opioid overdoses are among the most time-sensitive poisoning emergencies. The hallmark triad is altered mental status, respiratory depression, and pinpoint pupils. Naloxone (Narcan) is the specific antidote and is available to EMTs in most jurisdictions. It can be administered intranasally (2 mg per nostril) or intramuscularly (0.4 to 2 mg). The goal is to restore adequate respirations, not full consciousness. Over-correction can cause acute withdrawal symptoms including agitation, vomiting, and combativeness.
When administering naloxone, be prepared for the patient to become agitated or vomit. Position the patient in the recovery position if possible. Naloxone has a shorter duration of action than most opioids, so the patient may require repeat doses and must be transported for monitoring even if they initially improve.
General Poisoning Management
For all poisoning patients, focus on ABCs first. Ensure a patent airway, provide ventilatory support as needed, and monitor circulation. Contact Poison Control (1-800-222-1222) for guidance on specific substances. Do not induce vomiting unless specifically directed by Poison Control or medical direction. Collect any pill bottles, substances, or drug paraphernalia found at the scene and bring them to the hospital. Document the time of exposure, the amount ingested (if known), and any treatments provided.