[Risk assessment of rescue helicopter or ambulance transport of patients ingesting hazardous volatile materials].

Introduction: In cases of transport by rescue helicopter or ambulance of patients having ingested hazardous substances, medical personnel may be at a certain risk of inhaling the substances. However, few reports have addressed such risk of causing secondary casualties.

Purpose: This simulation study aimed to assess the risk of inhalation of hydrogen sulfide and chlo-opicrin in the cabin of a helicopter or an ambulance transporting a patient who has ingested calcium polysulfide or chloropicrin, which were previously reported to cause secondary casualties.

Method: Concentrations of hydrogen sulfide and chloropicrin were assessed on the following as-umptions :The patient ingested 100 mL of the causative or original chemical. All chemical substances reacted with the gastric juice or were thoroughly vomited and evaporated uniformly within the cabin space of the helicopter or ambulance. Environmental conditions were 20 *degrees at 1 atmosphere of pres-ure in a 5 m3 cabin volume in the helicopter and a 13.5 m3 cabin volume in the ambulance.

Results: In the case of calcium polysulfide ingestion which produced hydrogen sulfide, its concen-ration reached 774 ppm in the helicopter and 287 ppm in the ambulance. For chloropicrin ingestion, the concentrations were 4,824 ppm and 1,787 ppm, respectively.

Discussion: The simulated concentration of hydrogen sulfide was more than 500 ppm in the heli-opter, which may lead to respiratory paralysis and death. The simulated concentration of chloropicrin was more than 300 ppm, which has a risk of death within 10 minutes. Currently, as far as Japanese laws are concerned, there are no restrictions requiring pretransport assessment or setting criteria for transporting patients who might have ingested hazardous substances that could cause secondary casu-lties when vomited.

Conclusion: When patients who might have ingested hazardous chemicals are transported, it is important to recognize the risk of causing secondary casualties by vomiting the chemicals.