Cyanide and methemoglobin kinetics in smoke inhalation victims treated with the cyanide antidote kit.

Abstract

To evaluate serial cyanide, methemoglobin, and carbon monoxide levels in smoke inhalation patients. Regional poison center and regional toxicology treatment center. Seven critically ill smoke inhalation patients referred to the regional poison center. Peak level and half-life were determined by obtaining serial carboxyhemoglobin, cyanide, and methemoglobin levels. The mean observed half-life of cyanide was 3.0 +/- 0.6 hours. Methemoglobinemia was evaluated in four patients after sodium nitrite administration. The peak measured methemoglobin levels (mean, 10.5% +/- 2%; range, 7.9% to 13.4%) did not occur until a mean of 50 minutes (range, 35 to 70 minutes) following administration of sodium nitrite. The total oxygen-carrying capacity reduced by the combination of carboxyhemoglobin and methemoglobin was never more than 21% (range, 10% to 21%) in this series. The administration of sodium nitrite to smoke inhalation patients in the presence of concomitant carbon monoxide poisoning may be relatively safe.