Toxicology and applied pharmacology
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Toxicol. Appl. Pharmacol. · Oct 1995
Effect of oxygen and sodium thiosulfate during combined carbon monoxide and cyanide poisoning.
In a canine model of combined carbon monoxide (CO) and cyanide (CN) poisoning, cardiac output (QT) and oxygen consumption (Vo2) decreased but recovered to baseline values by 15 min after toxic exposure; elevated blood CN and lactic acidosis persisted for at least another 10 min. Given the rapid spontaneous recovery after cessation of toxic exposure, we questioned the efficacy of usual treatment with oxygen (O2) and sodium thiosulfate (Na2S2O3) for CN poisoning. Accordingly, in seven dogs (26 +/- 3 kg, chloralose and urethane anesthesia), we sequentially administered CO by closed circuit inhalation (231 +/- 42 ml) and potassium CN by intravenous infusion (0.072 mg.kg-1.min-1 for 17 +/- 3 min). ⋯ We conclude that O2 and Na2S2O3 therapy should be continued during combined CO and HCN poisoning. Oxygen increases CO elimination and can enhance anti-CN treatment. After infusion or inhalation of CN, when most CN has already penetrated the intracellular compartment, postexposure sodium thiosulfate increased the metabolism of CN.