Smoke inhalation victims (house fires) are at risk of carbon monoxide (CO) and cyanide poisoning (CN). CO exposure/poisoning can be readily evaluated by CO - Oximetry but CN level can be obtained in majority of the hospital.

Lactic acid level is often sent to evaluate for CN poisoning.

 

Bottom line:

1. Lactatic acid levels should be sent in all smoke inhalation victims.
2. Elevate lactate > 10 mmol/L is highly suggestive of CN poisoning
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Additional Information

In a manuscript published in 1991, N Engl J Med by Dr. FJ Baud is the source of this data.

CN blood levels were measured in 109 residetial fire victims in France prior to any treatment was initiated.

• 43 fire victims who died had mean blood CN level of 116.4 micromol/L
• 66 fire victims who survived had mean blood CN level of 21.6 micromol/L
• Plasma lactate level correlated more closely with blood CN level than blood CO level.
• Elevated lactate of 10 mmol/L was sensitive (87%) for CN level > 40 micromol/L (defined level of CN toxicity) with specificity of 94% and positive predictive value of 95%.

 

 

References

Baud FJ et al. Elevated blood cyanide concentrations in victims of smoke inhalation. N Engl J Med 1991;325:1761-6.