QUESTIONS and CONTROVERSIAL ISSUES

Other than fires, name other possible sources of carbon monoxide exposure.

• Auto exhaust
• Faulty heating equipment such as furnaces
• Charcoal grills and indoor hibachis
• Sterno and canned heat products
• Methylene chloride (furniture stripper)
• Indoor sporting events
  1. Tractor pulls
  2. Hockey games

What are the indications for hyperbaric therapy?

• Controversial
• Levels over 40% with symptoms
• Coma, LOC at the scene
• Seizures or significant neurologic impairment
• Cardiovascular compromise or ischemia
• Pregnancy with levels over 20%.

CLINICAL COURSE

At this juncture in the case, several members of the medical team note a distinct "smoked-almond" odor emanating from the fire fighter's clothing and skin.

What specific antidotes may be indicated in the setting of this acute poisoning? What are their mechanisms of action?

Besides CO, cyanide exposure should be considered in any fire victim.

Antidote: The Lilly Kit

• Amyl nitrate pearls: 3-5% MetHgb
• Sodium nitrate: 15-20% MetHgb (Dose: 10cc of 3% solution (300mg) over 5min)
• Sodium thiosulfate
  • (Dose: 50cc of 25% solution (12.5gm) at 3-5cc/min)
  • Mechanism
    1. Induces methemoglobinemia
    2. Attracts cyanide off the heme group of cytochrome oxidase forming cyanomethemoglobin
    3. Allows thiosulfate (via rhodanase enzyme) to detoxify the cyanide which is renally excreted.
• Hydroxycobalamin/sodium thiosulfate: future antidote?

CLINICAL COURSE

Upon arrival to the ED, the patient is orally intubated and placed on 100% oxygen. Because of his profound CNS impairment and elevated carboxyhemoglobin level, arrangements are made for hyperbaric oxygenation. Since cyanide poisoning is highly suspected, the patient is given the Lilly Kit with improvement in his mental status and acidotic state. Following HBO at 3 ATM, the patient recovers but suffers mild chronic neurobehavioral deficits.