Drowning occurs when a person’s breathing is impaired due to submersion or immersion in liquid. This compromises the airway, the path air takes to the lungs, making it impossible to breathe oxygen. The inability to take in air quickly leads to a lack of oxygen, impacting vital organs.
Water Aspiration
When a person is submerged in water and struggles to breathe, they may involuntarily inhale water into their lungs, a process known as water aspiration. This directly interferes with the lungs’ ability to perform their primary function: exchanging oxygen and carbon dioxide. The inhaled water displaces the air within the tiny air sacs, called alveoli, where gas exchange normally occurs. This displacement prevents oxygen from entering the bloodstream and carbon dioxide from being removed.
Even a small amount of aspirated water can trigger a significant reaction within the lungs. Water irritates the delicate lining of the alveoli, leading to inflammation and damage to the alveolar-capillary membrane. This damage can cause fluid from the bloodstream to leak into the lungs, resulting in pulmonary edema. This fluid buildup further hinders gas exchange.
Additionally, water can wash away surfactant, a substance that helps keep the alveoli open, causing them to collapse and reducing lung capacity. Foam, a mixture of air, water, and surfactant, can also fill the airways, creating another barrier to breathing.
Involuntary Airway Closure
The body possesses a protective reflex that can involuntarily close the airway when water is detected. This reflex, known as laryngospasm, involves the sudden closure of the vocal cords and larynx. It is a natural response designed to prevent water from entering the lungs. While this reflex can initially protect the lungs from water aspiration, it can also prevent air from entering.
This sustained airway closure can lead to a severe lack of oxygen, even if no water has reached the lungs. Laryngospasm can persist, sealing off the airway and contributing to asphyxia.
Physical Obstructions
Beyond water aspiration and involuntary reflexes, a drowning victim’s airway can also become blocked by various physical obstructions. One common occurrence is the regurgitation or vomiting of stomach contents. Due to a lack of oxygen, an individual may vomit. If unconscious or too weak to clear their mouth and throat, this material can be inhaled into the airways. Aspiration of vomit can cause a severe inflammatory reaction in the lungs and mechanically block air passages.
Foreign objects in the water environment can also compromise the airway. Debris such as mud, sand, weeds, small pieces of trash, or broken teeth can be inhaled or become lodged in the mouth and throat during submersion. These materials create a physical barrier, preventing air from reaching the lungs.
Another physical obstruction involves the tongue. When a person loses consciousness, muscles throughout their body relax, including those supporting the tongue. In a supine position, the relaxed tongue can fall backward against the throat, completely blocking the upper airway and preventing air from entering the lungs.
Impact of Injuries
Trauma sustained during a drowning incident can further complicate a victim’s ability to maintain an open airway and breathe. Injuries to the head, neck, or face can directly affect the structures involved in respiration. For example, severe impacts from hitting the bottom of a pool, a boat, or rocks can cause fractures, significant swelling, or internal bleeding in these areas. Such injuries can compress or obstruct the airway, making breathing difficult or impossible. Soft tissue swelling in the neck and face can develop over time, leading to delayed airway compromise.
Spinal cord injuries, particularly those affecting the cervical (neck) region, represent another way trauma can impact breathing. The nerves controlling the diaphragm and other breathing muscles originate from the spinal cord in the neck (C3-C5). Damage to these nerves can impair or paralyze the muscles responsible for breathing, even if the airway is physically clear. This can lead to a reduced ability to inhale and exhale effectively, resulting in respiratory failure.