Evaluation of prehospital hydroxocobalamin use in the setting of smoke inhalation

The indications for prehospital hydroxocobalamin are not well defined. The aim of this study was to evaluate prehospital signs and symptoms in patients who received hydroxocobalamin to improve future use.

In this retrospective study, all patients who received prehospital Hydroxocobalamin at a tertiary care burn center from December 2012 to March 2018 were reviewed. Each case was evaluated for evidence of suspected cyanide toxicity: hypotension, syncope, CNS depression/altered mentation, seizures, respiratory or cardiac arrest. A determination was made whether or not hydroxocobalamin was indicated.

In this study, EMS providers administered hydroxocobalamin to 42 patients between December 2012 and March 2018. The majority (71%) of suspected cyanide exposures were from house fires. The most common prehospital findings were coma or depressed CNS (36%), followed by hypotension (16%) and cardiac arrest (12%). Sixty percent of patients treated with hydroxocobalamin had none of the six clinical indicators for potential cyanide toxicity. Carboxyhemoglobin and serum lactate were significantly different in patients that had a clinical indication for hydroxocobalamin compared to those who did not.

Prehospital hydroxocobalamin was used empirically however, indications are unclear. Using defined clinical indications may provide greater clarity for providers and reduce unnecessary use of hydroxocobalamin.