4.4 Poisoning, Overdose & Environmental Emergencies
Key Takeaways
Four routes of poisoning exposure: ingestion, inhalation, injection, and absorption (skin/eyes)
Opioid overdose triad: pinpoint pupils (miosis), respiratory depression, and altered mental status
Naloxone (Narcan) dose: intranasal 4 mg or intramuscular 0.4-2 mg -- may need to repeat every 2-3 minutes
Carbon monoxide poisoning causes headache, nausea, confusion -- cherry red skin is a late/unreliable sign; SpO2 readings may be falsely normal
SLUDGEM mnemonic for organophosphate poisoning: Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis, Miosis
Hypothermia classifications: mild (90-95 degrees F), moderate (82-90 degrees F), severe (<82 degrees F)
Heat stroke is a life-threatening emergency with altered mental status and core temp >104 degrees F -- requires aggressive cooling
Near-drowning: prioritize airway management and ventilation; do NOT attempt to drain water from lungs
Poisoning, overdose, and environmental emergencies encompass a wide range of conditions. EMTs must be able to identify the type of exposure, recognize toxidromes (toxic syndromes), and provide appropriate treatment.
Routes of Poisoning Exposure
| Route | Examples | EMT Considerations |
|---|---|---|
| Ingestion | Medications, household chemicals, plants, contaminated food | Most common route; do NOT induce vomiting |
| Inhalation | Carbon monoxide, smoke, chemical fumes, gases | Ensure scene safety; remove patient from environment |
| Injection | Snake/insect bites, IV drug use, needle sticks | Look for injection sites; assess for envenomation |
| Absorption | Pesticides, chemical agents, poison ivy/oak | Remove contaminated clothing; irrigate skin |
General Poisoning Management
- Scene safety -- protect yourself from exposure
- Identify the substance if possible (bring container to hospital)
- Contact Poison Control Center: 1-800-222-1222
- Do NOT induce vomiting unless directed by Poison Control
- Manage ABCs and transport
- Bring all pill bottles, containers, or substances found at the scene
Opioid Overdose
The opioid epidemic has made this one of the most common overdose presentations EMTs encounter.
Common Opioids
- Heroin, fentanyl, carfentanil
- Prescription opioids: oxycodone, hydrocodone, morphine, methadone
Opioid Toxidrome (Classic Triad)
- Pinpoint pupils (miosis)
- Respiratory depression (slow, shallow, or absent breathing)
- Altered mental status (unresponsive or severely decreased consciousness)
Naloxone (Narcan) Administration
Naloxone is an opioid antagonist that reverses the effects of opioids.
| Route | Dose | Notes |
|---|---|---|
| Intranasal (IN) | 4 mg (one spray in one nostril) | Preferred prehospital route -- no needles |
| Intramuscular (IM) | 0.4-2 mg | Inject into deltoid or lateral thigh |
| Intravenous (IV) | 0.4-2 mg | ALS intervention |
Key Points:
- May repeat every 2-3 minutes if no response
- Onset: IN ~3-5 minutes, IM ~3-5 minutes, IV ~2 minutes
- Duration of naloxone (30-90 minutes) is shorter than most opioids -- patient may re-sedate
- Provide BVM ventilation while waiting for naloxone to take effect
- Patient may become agitated, combative, or experience withdrawal symptoms upon waking
- Be prepared for vomiting -- have suction ready
Carbon Monoxide (CO) Poisoning
Carbon monoxide is an odorless, colorless gas that binds to hemoglobin with 200-250 times greater affinity than oxygen, forming carboxyhemoglobin (COHb).
Sources
- Furnaces, water heaters, generators
- House fires, car exhaust
- Poorly ventilated spaces with combustion
Signs and Symptoms
- Early: Headache, nausea, dizziness, fatigue (often mistaken for flu)
- Progressive: Confusion, visual changes, chest pain, shortness of breath
- Severe: Seizures, loss of consciousness, cardiac arrest
- Cherry red skin -- classically taught but actually a late and unreliable sign
- SpO2 may read falsely normal (pulse oximeter cannot distinguish COHb from O2Hb)
Treatment
- Remove from exposure (ensure scene safety)
- High-flow oxygen via NRB at 15 L/min -- this is the primary treatment
- Half-life of COHb: ~4-6 hours on room air, ~60-90 minutes on 100% O2
- Transport to facility with hyperbaric oxygen capability if severe
Organophosphate Poisoning
Organophosphates (found in pesticides and nerve agents) inhibit acetylcholinesterase, causing excessive acetylcholine accumulation.
SLUDGEM Mnemonic
| Letter | Sign/Symptom |
|---|---|
| S | Salivation (excessive drooling) |
| L | Lacrimation (tearing) |
| U | Urination (involuntary) |
| D | Defecation (involuntary) |
| G | GI distress (cramping, nausea) |
| E | Emesis (vomiting) |
| M | Miosis (pinpoint pupils) |
Additional Signs
- Bradycardia
- Bronchospasm and bronchorrhea (excessive secretions)
- Muscle fasciculations (twitching)
- Seizures
EMT Treatment
- Decontaminate -- remove clothing, brush off dry chemicals, irrigate with water
- Protect yourself -- wear appropriate PPE (gloves, gown at minimum)
- Manage airway -- suction copious secretions
- High-flow oxygen
- Transport rapidly -- atropine (the antidote) is an ALS/hospital intervention
Hypothermia
Hypothermia occurs when core body temperature falls below 95 degrees F (35 degrees C).
| Severity | Core Temperature | Signs and Symptoms |
|---|---|---|
| Mild | 90-95 degrees F (32-35 degrees C) | Shivering, poor coordination, slurred speech, confusion |
| Moderate | 82-90 degrees F (28-32 degrees C) | Shivering stops, increasing confusion, drowsiness, cardiac dysrhythmias |
| Severe | <82 degrees F (<28 degrees C) | Unresponsive, no shivering, fixed dilated pupils, V-fib risk, appears dead |
Hypothermia Treatment
- Remove from cold environment
- Remove wet clothing and cover with warm blankets
- Handle the patient gently -- rough handling can trigger V-fib in severe hypothermia
- Apply heat to the core (neck, armpits, groin) -- passive external rewarming
- Administer warm, humidified oxygen if available
- Do NOT rub extremities or apply direct heat to arms/legs
- In severe hypothermia: "They're not dead until they're warm and dead" -- continue resuscitation
Hyperthermia
Heat Exhaustion vs. Heat Stroke
| Feature | Heat Exhaustion | Heat Stroke |
|---|---|---|
| Mental status | Normal or mild confusion | Altered (confusion, seizures, coma) |
| Skin | Cool, pale, diaphoretic (sweaty) | Hot, red; may be dry or wet |
| Core temp | <104 degrees F (<40 degrees C) | >104 degrees F (>40 degrees C) |
| Severity | Urgent | Life-threatening emergency |
Heat Stroke Treatment
- Aggressive cooling is the priority
- Move to cool environment, remove excess clothing
- Apply cold packs to neck, armpits, groin (areas with large blood vessels)
- Fan the patient while misting with water
- Cold IV fluids (ALS)
- Rapid transport
Drowning
- Remove from water (ensure rescuer safety)
- C-spine precautions if diving injury suspected
- Priority is ventilation -- begin rescue breathing/BVM immediately
- Do NOT attempt to drain water from lungs (abdominal thrusts are not effective)
- Even if patient appears to recover, transport for observation (risk of delayed pulmonary edema)
Bites and Stings
Snake Bites
- Keep patient calm and still (reduces venom spread)
- Immobilize the affected extremity at or below heart level
- Mark the edge of swelling with a pen and note the time
- Do NOT apply a tourniquet, ice, or attempt to suck out venom
- Transport to facility with antivenom capability
Spider Bites
- Black widow: Severe muscle pain, abdominal rigidity, hypertension
- Brown recluse: Initially painless, develops into necrotic wound over hours/days
- Treatment: Clean wound, ice, pain management, transport
Marine Envenomation
- Jellyfish: rinse with vinegar (acetic acid), remove tentacles with tweezers
- Do NOT rinse with fresh water (can cause nematocyst discharge)
An unresponsive patient is found with a respiratory rate of 4, pinpoint pupils, and a syringe nearby. The EMT should FIRST:
Administer intranasal naloxone
Begin BVM ventilation with supplemental oxygen
Perform a detailed physical exam to find the injection site
Place the patient in the recovery position and monitor
The intranasal dose of naloxone (Narcan) for a suspected opioid overdose is:
0.4 mg
2 mg
4 mg
8 mg
Why is pulse oximetry unreliable in carbon monoxide poisoning?
Carbon monoxide destroys the pulse oximeter sensor
The pulse oximeter cannot distinguish between oxyhemoglobin and carboxyhemoglobin
Carbon monoxide causes peripheral vasoconstriction that blocks the signal
Pulse oximetry only works with oxygen-rich blood
A farmer is found in a field with excessive salivation, lacrimation, urination, and pinpoint pupils after spraying pesticides. This presentation is consistent with:
Opioid overdose
Sympathomimetic toxicity
Organophosphate poisoning
Carbon monoxide exposure
Which finding differentiates heat stroke from heat exhaustion?
Nausea and vomiting
Muscle cramps
Altered mental status
Elevated heart rate
When managing a severely hypothermic patient, why should the EMT handle the patient gently?
To prevent frostbitten skin from breaking
Rough handling can trigger ventricular fibrillation in the cold heart
Movement causes further heat loss through convection
The patient is likely to have brittle bones from calcium loss
A near-drowning victim has been pulled from the water and is not breathing. After ensuring scene safety, the EMT should:
Perform abdominal thrusts to expel water from the lungs
Begin chest compressions immediately
Provide ventilations with a BVM and supplemental oxygen
Roll the patient onto their side to drain water from the airway
An important consideration when administering naloxone to a patient with suspected opioid overdose is that:
Naloxone permanently reverses all opioid effects
The duration of naloxone is shorter than most opioids, so the patient may re-sedate
Naloxone works immediately regardless of the route of administration
Only one dose of naloxone should ever be administered
Match each poisoning or overdose type to its classic signs and symptoms:
Match each item on the left with the correct item on the right
Opioid overdose
Carbon monoxide poisoning
Organophosphate poisoning
Sections you finish are checked off in the contents.