Cyanide toxicity in burned patients.

The role of cyanide (CN) in smoke inhalation injury has been the subject of investigation for many years. Prospective evaluation of serum CN, thiocyanate (the primary metabolic product of CN), and carboxyhemoglobin (COHb) in patients suspected by history of having smoke inhalation injury was performed in 144 patients. Eight of 12 patients with "lethal" CN levels (greater than 1.0 mg/L) died. All had sublethal levels of COHb. A separate group of patients who were DOA following fatal burn injuries were also studied. Lethal CN levels were found in 12 of 14 victims with lethal COHb levels and in 14 of 20 victims with sublethal COHb levels. The results show that elevated CN levels are frequent in patients with smoke inhalation and suggest that cyanide toxicity is a contributor to severe inhalation injuries. In some cases, CN was the primary measured toxicant.