CFRN Environmental and Toxicological Emergencies 2 — Questions and Answers
Question 1: A patient presents with altered mental status, tachycardia, diaphoresis, and hyperthermia after exposure to an organophosphate insecticide. Which antidote should be administered first?
- Pralidoxime (2-PAM)
- Atropine (Correct answer)
- N-acetylcysteine
- Flumazenil
Correct answer: Atropine
Atropine is the first-line antidote for organophosphate poisoning as it blocks muscarinic effects; pralidoxime should follow but atropine takes priority.
Question 2: During flight transport of a patient with suspected carbon monoxide poisoning, the pulse oximeter reads 98%. What is the most accurate interpretation?
- The patient is well-oxygenated and CO poisoning is unlikely
- Pulse oximetry is unreliable because it cannot differentiate oxyhemoglobin from carboxyhemoglobin (Correct answer)
- The reading confirms adequate tissue oxygenation
- The SpO2 of 98% means no supplemental oxygen is needed
Correct answer: Pulse oximetry is unreliable because it cannot differentiate oxyhemoglobin from carboxyhemoglobin
Standard pulse oximetry cannot distinguish carboxyhemoglobin from oxyhemoglobin, so it may falsely appear normal despite severe CO poisoning.
Question 3: A hiker rescued from a high-altitude environment develops pulmonary edema at 14,000 feet. What is the most appropriate initial intervention?
- Administer IV furosemide and maintain altitude
- Descend immediately and administer supplemental oxygen (Correct answer)
- Initiate positive pressure ventilation only
- Give nifedipine and continue ascent
Correct answer: Descend immediately and administer supplemental oxygen
Immediate descent combined with supplemental oxygen is the definitive treatment for high-altitude pulmonary edema (HAPE).
Question 4: A patient was stung by multiple Africanized honeybees and is now showing signs of anaphylaxis. After administering epinephrine, which additional medication is most critical in flight?
- Oral diphenhydramine only
- IV corticosteroids and IV antihistamines (Correct answer)
- Calcium gluconate
- Magnesium sulfate
Correct answer: IV corticosteroids and IV antihistamines
IV corticosteroids and antihistamines are used after epinephrine to prevent biphasic anaphylaxis and reduce ongoing inflammatory response.
Question 5: A patient with tricyclic antidepressant (TCA) overdose develops a wide QRS complex and hypotension. What is the treatment of choice?
- Magnesium sulfate IV bolus
- Sodium bicarbonate IV bolus (Correct answer)
- Calcium chloride IV bolus
- Amiodarone IV bolus
Correct answer: Sodium bicarbonate IV bolus
Sodium bicarbonate alkalinizes the serum and reverses TCA-induced sodium channel blockade, narrowing the QRS and improving hemodynamics.
Question 6: While transporting a patient with suspected cyanide poisoning from an industrial fire, which finding most specifically suggests cyanide toxicity over simple CO poisoning?
- Cherry-red skin discoloration
- Elevated venous oxygen saturation with profound metabolic acidosis (Correct answer)
- Bilateral crackles on auscultation
- Bradycardia and miosis
Correct answer: Elevated venous oxygen saturation with profound metabolic acidosis
Cyanide inhibits cellular respiration causing elevated venous pO2 (cells cannot use oxygen) along with severe lactic acidosis.
Question 7: A patient is brought in after ingesting a large quantity of acetaminophen 4 hours ago. Which laboratory value is most important to guide treatment decisions?
- AST and ALT levels
- Serum acetaminophen level plotted on the Rumack-Matthew nomogram (Correct answer)
- Prothrombin time/INR
- Serum creatinine
Correct answer: Serum acetaminophen level plotted on the Rumack-Matthew nomogram
The Rumack-Matthew nomogram uses a timed serum acetaminophen level (4–24 hours post-ingestion) to determine whether N-acetylcysteine is indicated.
CFRN Environmental and Toxicological Emergencies 2
A patient presents with altered mental status, tachycardia, diaphoresis, and hyperthermia after exposure to an organophosphate insecticide.
Which antidote should be administered first?