Pathomorphological changes due to helium inhalation: an expert case report

BACKGROUND: Helium, being an inert substance, does not have a significant effect on the human body, but sometimes at very high concentrations in the air, it can cause suffocation and a state of oxygen deficiency. Oxygen-helium therapy has proven to be the most effective recovery, rehabilitation, and treatment for all types of lung damage and reduced saturation. It is even included in the recommendations for preventing, diagnosing, and treating COVID-19. Deaths due to inhalation of inert gases, especially helium, are sporadic in forensic practice. As a rule, the probability of death in such cases is most often associated with man-made accidents or violations of safety regulations when performing technological processes and operations related to the use of gas. Safety instructions for handling helium warn of possible damage to the mucous membrane of the eyes and frostbite of the skin, as well as mechanical injury when a heavy gas cylinder falls. CASE PRESENTATION: Inert gases do not interact with other chemicals. However, we encountered a suicide case where an inert gas was chosen as a means. Inhalation of helium caused macro- and micromorphological changes in the human body, which led to a fatal outcome. The case is illustrated by photographs of microscopic preparations, which demonstrate the absence of specific signs of toxic effects on the organs and tissues of the deceased. CONCLUSION: Despite the substances extreme volatility, the compressed gass pressure and low temperature can cause various injuries and even death. The study of general pathomorphology can be helpful in the conduct of a forensic medical examination.