J. S. Vazquez1,2, L. S. Johnson1,2, T. E. Travis1,2, L. T. Moffatt2, J. W. Shupp1,2 1MedStar Washington Hospital Center,The Burn Center, Department Of Surgery,Washington, DC, USA 2Firefighters’ Burn And Surgical Research Laboratory,Washington, DC, USA
Introduction:
Hydrogen cyanide is produced during combustion of several different types of household materials such as synthetic polymers. This small lipid soluble molecule inhibits oxidative phosphorylation and produces a severe lactic acidosis in affected patients. Early identification of cyanide (CN) toxicity allows for treatment with Hydroxocobalamin, a CN binding agent that forms cyanocobalamin, a non-toxic substance excreted by the kidneys. However, even though the medication has a mild safety profile, its high cost should guide judicious use. We evaluated the appropriateness of a single burn center’s administration of Hydroxocobalamin in patients with inhalation injury suspected of having CN intoxication.
Methods:
In this single center retrospective study, pharmacy records where queried for patients that received Hydroxocobalamin between January 2014 through June 2017. Twenty-seven patients received treatment based on the suspicion of inhalation injury and CN toxicity and where included in this study. The electronic medical record of those patients was queried to collect data regarding survival status, clinical parameters, and details surrounding Hydroxocobalamin administration. Blood CN levels were drawn either prior to or immediately after Hydroxocobalamin administration in 20 patients. Clinical criteria for out of hospital administration of Hydroxocobalamin by EMS was decreased GCS in the setting of inhalation injury. As for patients arriving to the trauma bay clinical criteria for physician administration of Hydroxocobalamin was acidosis out of proportion to CO2 retention and an elevated CO level in the setting of inhalation injury.
Results:
A total of 27 patients (mean age 48.9 years; 17 men) were treated with Hydroxocobalamin based on the suspicion of CN poisoning in the setting of inhalation injury. House fires (74%) were the most common cause injury overall. Sixteen patients had GCS <8. A concomitant burn injury was present in 78% of patients (%TBSA 0-95). After correcting for smoking status, 70% of patients had CN levels above normal range (Max 2.79mg/L). Presence of an elevated CN level was used as a surrogate for accuracy of administration. All patients arrived at the burn center within the cyanide half-life. Mortality was 37% in this patient cohort.
Conclusion:
A high index of suspicion should be maintained for the presence of CN toxicity in patient with concomitant burn and inhalation injury. Treatment for CN poisoning should be initiated in any patients with inhalation injury, unexplainable lactic acidosis, or impaired consciousness that cannot be explained only by CO poisoning. In this study, we demonstrated that the medication was administered correctly in 70% of patients. Given the broad therapeutic index of Hydroxocobalamin and the mortality associated with cyanide toxicity, this medication should be used when the correct clinical scenario is present, although the high cost might be a barrier for some centers around the world.