Submersion injuries are a significant health concern, capable of causing a wide range of physical effects from temporary distress to severe, lasting consequences. This type of incident involves a person being submerged in a liquid, leading to breathing difficulties and a cascade of physiological responses.
Defining Submersion Injury
A submersion injury occurs when an individual experiences respiratory impairment because their mouth and nose are submerged or immersed in a liquid. This broad definition encompasses both incidents that result in death and those where the person survives. The term “submersion injury” is now the preferred medical terminology, replacing older phrases like “near-drowning.” Historically, terms such as “wet drowning,” “dry drowning,” and “secondary drowning” were used, but these are no longer recommended due to inconsistencies and a lack of clear medical distinction.
Physiological Impact
During a submersion event, the body undergoes physiological changes primarily due to oxygen deprivation. These changes affect multiple organ systems, with the most immediate and profound impact seen in the respiratory and neurological systems.
The respiratory system is directly affected as the individual initially holds their breath, followed by involuntary gasping. This leads to the aspiration of liquid into the lungs. Even a small amount of aspirated fluid can interfere with gas exchange within the lungs.
The aspirated water can damage or wash out surfactant, a substance that helps keep the lung’s air sacs open, leading to alveolar collapse and impaired oxygen transfer. This can progress to pulmonary edema, a buildup of fluid in the lungs, and acute respiratory distress syndrome (ARDS). Another common respiratory complication is pneumonia, which can result from inhaling contaminated water or gastric contents.
The neurological system is vulnerable to oxygen deprivation, known as hypoxia. Brain cells can suffer damage and die within four to five minutes without oxygen supply. This can lead to anoxic brain injury, impacting functions like memory, speech, and motor control. Cerebral edema, or brain swelling, is a common consequence of prolonged oxygen deprivation. In some instances, particularly with cold water submersion, hypothermia may reduce the brain’s metabolic rate, offering a protective effect.
The cardiovascular system is also affected by the lack of oxygen and potential hypothermia. Oxygen deprivation can lead to cardiac arrhythmias, such as irregular heartbeats, and in severe cases, cardiac arrest. Hypovolemia, a decrease in blood volume, and reduced heart muscle function can occur due to asphyxia. Increased resistance in the pulmonary blood vessels can further strain heart performance.
Beyond these primary systems, other bodily functions can be disrupted. While less common, electrolyte imbalances can occur if a large volume of water is aspirated, especially in highly saline environments. Kidney impairment is a possible consequence of widespread oxygen deprivation.
Spectrum of Injury and Outcomes
The outcomes following a submersion injury vary, ranging from a complete recovery to severe long-term effects. The severity of the injury and the prognosis depend on several factors, including the duration of submersion, the temperature of the water, and the speed and effectiveness of medical intervention. Prompt and effective resuscitation is the most important factor for improving a patient’s chances of a good outcome.
Pneumonia, an infection of the lungs, may not manifest immediately but can develop hours or even days after the initial incident. Long-term consequences are linked to neurological damage caused by oxygen deprivation. These can include cognitive deficits, such as problems with memory and learning, motor impairments affecting movement, and in severe cases, a persistent vegetative state. Even incidents initially appearing minor can sometimes lead to delayed or subtle symptoms.
Certain factors can influence the risk and outcome. Young children and older adults are often more vulnerable to severe outcomes. Pre-existing medical conditions and the specific conditions of the water environment also play a role. Many individuals who experience significant brain damage from a submersion injury require extensive long-term rehabilitation and support.