What are the safety concerns for emergency medical technicians and hospital staff following exposure to sodium azide?
The most probable routes of exposure for prehospital and hospital staff include dermal contact with sodium azide or inhalation of gaseous hydrazoic acid; inhalational exposure is most concerning.1 In one case, hospital-staff members developed headaches, light-headedness, and nausea while treating a patient for azide poisoning; however, staff exposure was not confirmed and no sequelae were evident.10
More objectively, workers at an azide plant exposed to azide concentrations above the occupational exposure limit developed headaches, hypotension, and palpitations.11 Another study found no evidence of kidney, heart, or liver damage after patients were given sodium azide for more than a year during a clinical trial.12 Not unexpectedly, there is little risk of exposure when proper safety precautions are taken.
Emergency response personnel should carefully inspect the scene for the presence of any sodium azide powder, and should also question bystanders and family members to determine if anyone performed mouth-to-mouth resuscitation on the patient. Standard universal precautions, along with attentiveness to one’s surroundings, should be sufficient to prevent dermal exposure. If small amounts of sodium azide residue are found on the patient, his or her clothes should be cautiously removed and placed in a plastic bag to prevent dispersion of particles. If large quantities of sodium azide are present on a patient, the hazardous materials response team should be called, in accordance with institutional and regional protocols. To avoid explosion, every attempt should be made to prevent azide salt (eg, from emesis) from contact with any metal surfaces (eg, oxygen tanks, metal stretcher).13Vomit from patients who have ingested sodium azide can cause liberation of hydrazoic acid, which can escape through the esophagus. A pungent ambient odor may provide a warning, which is particularly concerning in a confined space such as an ambulance. As a precaution, EMS personnel should open windows and maximize ventilation. After the call, EMS and hospital personnel should thoroughly wash their hands with soap and water, and change their uniform if they believe it has been contaminated. There is no risk of delayed exposure following exposure to hydrazoic acid.
During autopsy, medical examiners must exercise caution due to the potential for liberation of hydrazoic acids from the stomach.14Unless it is absolutely necessary, the medical examiner should avoid opening the stomach. If this is unavoidable, the autopsy should occur in a well-ventilated setting with the examiner wearing a supplied air respirator to limit exposure in a high-risk scenario.
Case Conclusion
None of the exposed first responders experienced dizziness, light-headedness, or irritation, and after a period of observation in the ED, they were discharged home without further sequelae. All hospital staff involved in the patient’s care, including those who performed cardiopulmonary resuscitation on the patient and cleaned his room, were advised to use protective equipment when handling the patient and bodily secretions. None of the health care workers developed abnormal clinical findings. Given the hazard in conducting a full postmortem examination, the medical examiner opted to send blood, bile, urine, and vitreous humor out for analysis, but did not conduct a full postmortem examination. Notably, the stomach was not opened, and its contents were not exposed.