Impact of Protocol Development on Hydroxocobalamin Use for Smoke Inhalation Injury with Suspected Cyanide Toxicity: A Pre-Post Analysis

BACKGROUND: Over 357 500 structure fires occur in the United States annually, resulting in 2710 civilian deaths. Combustion of plastic, vinyl, wood, silk, and petroleum can release toxic hydrogen cyanide gas. Empiric treatment with hydroxocobalamin has been advocated for cyanide toxicity without clear guidelines, and overuse can occur. Our study objective was to evaluate protocol compliance for the use of hydroxocobalamin for inhaled cyanide toxicity pre- and post-implementation of criteria and a smart order set. METHODS: We performed a retrospective review of compliance for the use of hydroxocobalamin, pre- (2022) versus post-implementation (2023-2024) of protocol criteria in patients with inhalation injury. Patients would receive hydroxocobalamin if they were exposed to smoke in an enclosed space, had the injury within 2 hours, experienced a cardiac arrest at the scene or prior to hospital arrival, had a Glasgow Coma Score < 10 at the scene or admission, or had lactate >10 and carboxyhemoglobin >10. Patients without an inhalation injury were excluded. Baseline demographics, laboratory values, and medication administration data were collected. RESULTS: Overall, 127 patients met inclusion criteria, 62 in the pre-protocol group and 65 in the post-protocol group. Appropriate utilization of the antidote based on the protocol criteria was 29% in the pre-group vs. 48% in the post-group. Administration of the antidote 2 hours after exposure was the most common reason for protocol deviation in both groups. There were no differences in mortality rates, hospital or ICU length of stay, or duration of mechanical ventilation between groups. CONCLUSION: Identification of patients with risk factors for inhalation injury with cyanide toxicity is key. Development of criteria for use ensures judicious stewardship of this antidote.