asphyxia

Asphyxia is a condition resulting from insufficient oxygen delivery to the body or from an inability to use oxygen, leading to cellular hypoxia and potentially death. It occurs when respiration is blocked, the airway is obstructed, or environmental or chemical factors prevent oxygen uptake or use.

Common mechanisms include mechanical obstruction (suffocation, strangulation, choking), drowning, and exposure to gases or toxins that disrupt oxygen transport or cellular respiration (carbon monoxide, cyanide, hydrogen sulfide). The term also covers metabolic forms where cells cannot utilize oxygen despite its presence.

Pathophysiology involves reduced arterial oxygen (hypoxemia) and often impaired carbon dioxide removal (hypercapnia), causing acidemia and energy failure that most severely affect the brain and heart. Chemical asphyxiants can cause death by preventing cellular respiration even when oxygen is present.

Clinical features vary by cause but commonly include shortness of breath, confusion, loss of consciousness, seizures, and cyanosis. If the airway is blocked or breathing ceases, rapid intervention is required.

Treatment focuses on removing the source of asphyxia, ensuring airway patency, and restoring oxygen delivery, typically with high-flow oxygen and resuscitation as needed. In cases of carbon monoxide poisoning, supplemental oxygen or hyperbaric oxygen therapy may be used; cyanide poisoning requires specific antidotes when appropriate.

Prevention emphasizes safety measures to prevent airway obstruction, drowning, and exposure to hazardous gases in workplace and domestic environments.

In forensic medicine, asphyxia is a recognized cause of death, with investigators considering its various forms when determining manner and cause of death.