The effects of declined oxygen levels on hypoxia symptoms and blood gases: An experimental study

Environmental suffocation is a form of asphyxia. In such cases, an autopsy alone is not sufficient to determine the cause of death, and forensic pathologists need environmental data from the scene and the symptoms of hypoxia from the victim. Considering that the symptoms of hypoxia vary widely, the analysis of gases in the blood is used to assess the level of oxygenation in humans. No research has yet equated a specific level of oxygen in the air with environmental suffocation. This study aimed to determine the correlation among the decreased level of oxygen in the environment, the values of blood gases, and the emergence of the symptoms of hypoxia. Pig animal model (Sus scrofa) was used. This study induced a state of environmental suffocation in the pigs, which were placed in a chamber with oxygen levels decreasing from 21% to 11% and then to 7%. At each oxygen level, the symptoms of hypoxia and the values of arterial blood gases were assessed. It is concluded that the decreased oxygen levels in the chamber resulted in hypoxia symptoms such as changes in the respiratory rate, heart rate, and blood gases, such as the pH, PO₂, PCO₂, HCO₃, BE, and O₂ saturation values. These changes had different percentages that reflect each range of the decreased oxygen levels in the chamber.