20.2 Toxicology

Domain 4.H.2 of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests Toxicology as toxidrome recognition and time-critical antidotes. Evolved-gas disorders such as decompression sickness (DCS) and high-altitude pulmonary edema (HAPE) were removed from the 2026 Examination Content Outline (ECO); they are not a tested 2026 lecture.

Name the toxidrome first

An antidote without a toxidrome is guessing. Use the vital signs, pupils, skin, and bowel to sort the room before you open the drug box.

Wet, agitated skin is sympathomimetic; dry, mad skin is anticholinergic. That finding decides ice-and-benzodiazepines versus an anticholinergic workup at the receiving hospital.

Antidotes that change the hop

Titration, seizures, and sodium-channel blockade

Naloxone is titrated to ventilation, not to a fighting Glasgow Coma Scale of 15. Restore a respiratory rate and airway tone. A 2-milligram slam in a long-term opioid user turns a breathing problem into a violent cabin problem and can precipitate withdrawal pulmonary edema. Start low when you can, repeat, and be ready to bag. Short-acting naloxone can wear off before a long-acting opioid does; watch the rate after you close the door.

Benzodiazepines are first-line for sympathomimetic agitation and for almost every toxin-related seizure. Do not reach for phenytoin as the flight move. Cool the hyperthermic methamphetamine or cocaine patient the same way you cool heat stroke: ice packs, wet sheets, benzos for shivering. A seizing, rigid, hot patient is a temperature and airway problem, not a destination debate.

Sodium bicarbonate is the sodium-channel / tricyclic antidepressant (TCA) move. A widening QRS, a deep terminal R in aVR, and hypotension after a TCA or another sodium-channel blocker get bicarbonate boluses, hyperventilation toward a high-normal pH per protocol, and a receiving intensive-care bed. Bicarbonate is not a generic "overdose fluid."

Shock infusions, gases, and the acetaminophen clock

Calcium-channel blocker (CCB) overdose is bradycardia, hypotension, and often hyperglycemia (insulin release is blocked). Give IV calcium and start high-dose insulin euglycemia therapy (HIET) with dextrose and potassium surveillance. Beta-blocker (BB) overdose looks similar but glucose is often low or normal. Glucagon is the classic BB adjunct; HIET is used for both when shock persists. These infusions belong on a pump, not as a single "push and fly."

Fomepizole blocks alcohol dehydrogenase for methanol and ethylene glycol. It is a receiving-hospital drug, not a cabin stock item. Chart the time of ingestion, the osmolar gap if you have it, and do not wait for blindness or oxalate crystals to choose a toxicology-capable destination.

Cyanide (CN) from closed-space fire or industrial exposure gets hydroxocobalamin (Cyanokit). Expect red skin and a ruined colorimetric laboratory panel after the dose. Do not delay oxygen and supportive care while you hunt a perfect lactate. Hydroxocobalamin is not the default for every fire victim who already has a documented carbon-monoxide level and no cyanide picture.

Carbon monoxide (CO) binds hemoglobin more tightly than oxygen. Pulse oximetry lies — it reads CO-hemoglobin as if it were oxyhemoglobin. Place the patient on 100 percent oxygen by nonrebreather or tube and choose a destination with hyperbaric oxygen (HBO) capability when there is loss of consciousness, pregnancy, persistent neurologic findings, or a high CO-oximetry reading. One hundred percent oxygen shortens CO half-life; HBO shortens it further. A "normal" pulse-ox of 98 percent does not clear the scene.

Acetaminophen toxicity is a clock. N-acetylcysteine (NAC) is the antidote. The Rumack–Matthew nomogram needs a time of ingestion and a four-hour (or later) level. If the time is unknown or the patient is already toxic, start NAC rather than waiting for a perfect plot. Chart the time for the receiving team. Late presenters with rising transaminases need a liver-capable hospital, not the nearest empty stretcher.

Organophosphate and the dirty aircraft

Organophosphate and nerve-agent cholinergic crisis is a crew-safety problem first. Bronchorrhea and diarrhea contaminate every surface. Decontaminate before you load. Do not fly a dirty cholinergic patient. Clothes go into sealed bags. The cabin is a closed box; what is on the patient is on the crew.

• Atropine is dosed to dry secretions, not to a magic heart-rate number. You may need far more than a code-cart syringe.
• Pralidoxime (2-PAM) regenerates acetylcholinesterase if given before aging is complete. Follow your program protocol.
• Intubate for failure, not for a pretty saturation on a soaking stretcher.
• Suction continuously. Bronchorrhea will refill the tube.

Cabin and destination

Protect the crew. Bag the clothes. Ventilate the cabin. Keep suction ready. Match destination to the antidote you cannot carry: HBO for severe CO, hydroxocobalamin if not already given, fomepizole and dialysis for toxic alcohols, NAC and a liver unit for late acetaminophen. A wide-complex TCA patient needs a bicarbonate-capable intensive-care bed, not a clinic pad.

Use the CFRN practice bank. Toxidrome tables in the CEN study guide and CCRN study guide still apply—then add decontamination and destination before the rotors turn.