Morning Report: 11/5/2013

Thanks to Dr. Paulson for today’s Morning Report!

Toxicology Corner

The bat phone rings: “There’s a fire in the area, how many critical/non-critical beds do you have?”

Dr. Silverberg: “1 million of each”

Carbon Monoxide (CO) and Cyanide exposure

Carbon Monoxide

– Rapidly absorbed across the alveolar membrane

– Binds hemoglobin approx 250x greater affinity than oxygen, forming COHgb

– COHbg decreases O2 content (but NOT O2 sat!!)

– Binds myoglobin –> myocardial/skeletal muscle hypoxia

– Binds cytochrome oxidase –> impairs mitochondrial O2 utilization

– Induces lipid peroxidation in CNS –> delayed neuro sequelae (assoc with brief LOC, occurs 2-40days later, mean 15days)

– ME uses >50% as minimum level for lethality>60%Seizure/coma/death/destruction/despair/apocalypse

– EMS will bring most patients who are symptomatic to a hyperbaric facility (Jacobi, Cornell)

ps. normal COHgb 1-2% (in smokers 5-10%)

Treatment: 100% O2

– Hyperbaric O2?

– with evidence of end organ damage, or persistent sxs after surface O2

– COHgb > 25%, or >15% in pregnant women

Cyanide

– Binds cytochrome oxidase –> impairs mitochondrial O2 utilization

– Enhanced release of excitatory neurotransmitters via NMDA receptor activation

– Induces lipid peroxidation in CNS

Suspect in all fire victims, but also..

– Bitter almond odor? only detected by 60% of pop

– Lactate >10 with severe metabolic acidosis, increased anion gap

Dx confirmed with cyanide level… but it’s a send out (wah waaaah)

Plasma CN: normal 4-5mcg/L, asymptomatic <80mcg/L, death >260mcg/L

Treatment: first and always- supportive care (CABs)

• Cyanide antidote kit (CAK, or Lilly kit)

= amyl nitrite, sodium nitrite (MetHgb), sodium thiosulfate (excretion in urine)

– Goal to induce 20-30% MetHgb  (can be tolerated without sig adverse effects) – CN has higher affinity for MetHgb than cytochrome a₃

•  Hydroxocobalamin (“Cyanokit”)

– Binds CN to form Cyanocobalamin (B12) – excreted for the next couple weeks (and the patient becomes a nice shade of orange).

-EMS will provide 3 blood samples taken prior to the administration of the drug.

Dilemma: CO and CN usually go together!

CO and MetHgb = fatal

Suggested mgmt: sodium thiosulfate and/or hyrodroxocobalamin,

i.e. leave out the nitrites if you have concern for CO

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Jay Khadpe MD

• Editor in Chief of "The Original Kings of County"
• Assistant Professor of Emergency Medicine
• Assistant Residency Director
• SUNY Downstate / Kings County Hospital

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