Drowning
Drowning is a serious and often fatal condition that occurs when an individual suffocates due to submersion in a liquid, typically water. It is a leading cause of accidental death, particularly among young children and certain high-risk groups. The process of drowning can involve the aspiration of water into the lungs, leading to suffocation, or in some cases, a laryngospasm that prevents water from entering the lungs. Survivors of near-drowning incidents may experience varying degrees of neurological effects, depending on factors such as the duration of submersion and water temperature. Immediate rescue and medical intervention are critical for improving outcomes, as prompt treatment can mitigate severe complications like brain injury or cardiac arrest.
Risk factors for drowning include age, swimming ability, and certain medical conditions, with children aged one to four being particularly vulnerable. Preventative measures are crucial, which include adult supervision, swimming education, and safety barriers around water. Recent initiatives, such as the National Water Safety Action Plan in the U.S., aim to reduce drowning incidents through enhanced safety protocols and awareness. Additionally, climate change is increasingly recognized as a factor that may elevate drowning risks due to more frequent and severe flooding events and extreme weather conditions.
Drowning
ANATOMY OR SYSTEM AFFECTED: Brain, circulatory system, heart, kidneys, lungs, nervous system, respiratory system, stomach, throat
DEFINITION: A drowning victim dies by suffocation from submersion in a liquid medium, usually water
Causes and Symptoms
Drowning is one of the leading causes of accidental death. The victim dies by suffocation from submersion in a liquid medium. Although suffocation most commonly results from the aspiration of fresh or salt water into the lungs, about 10 to 20 percent of victims experience a laryngospasm with subsequent glottic closure, followed by asphyxiation.
Near-drowning is defined as recovery after submersion.
Victims of near-drowning, if rescued and resuscitated quickly enough, may fully recover. In many instances, however, near-drowning survivors are left with mild to severe neurologic effects. Even if the person has been submerged in water for some time, vigorous attempts at resuscitation are indicated because of documented recovery following such incidents.
Factors that influence the extent of damage in near-drowning include the length of time submerged, the temperature of the water, and the person’s resistance to asphyxia and anoxia (oxygen deprivation). Recovery may be more successful if the person drowns in cold water because the induced hypothermia lowers the body’s metabolic demands and, therefore, its oxygen needs. However, extremely cold water may decrease the person's core body temperature so rapidly that death from hypothermia may actually occur before drowning.
Generally, there is an inverse relation between the person's age and their resistance to asphyxia and anoxia: the younger the person, the greater the resistance. The resistance is especially strong in very young children, usually under two or three years of age, because of the diving reflex triggered in young children when the face is immersed in very cold water. In the diving reflex, blood is shunted to the vital organs, especially the brain and heart. Hypothermia offers some protection to the hypoxic brain by reducing the cerebral metabolic rate. Although the person suffers severe bradycardia, the remaining oxygen supply is concentrated in the heart and brain. The diving reflex is generally not a factor in adult drownings.
Approximately 10 percent of drowning victims develop laryngospasm concurrently with the first gulp of water and thus do not aspirate (swallow) fluid. Among the majority who do aspirate, the amount of fluid aspirated is small. In the past, saltwater and freshwater drowning were differentiated, but these differences are of little clinical significance in humans, mainly because so little fluid is aspirated. In both cases, drowning quickly diminishes perfusion to the alveoli. This interferes with ventilation and soon leads to hypoxemia, ineffective circulation, cardiac arrest, brain injury, and brain death.
When water is aspirated into the lungs, the composition of the water is a key factor in the pathophysiology of the near-drowning event. Aspiration of freshwater causes surfactant to wash out of the lungs. Surfactant reduces surface tension within the alveoli, increases lung compliance and alveolar radius, and decreases the work of breathing. Loss of surfactant from freshwater aspiration destabilizes the alveoli and leads to increased airway resistance.
Conversely, salt water—a hypertonic fluid—creates an osmotic gradient that draws protein-rich fluid from the vascular space into the alveoli. The consequences of both types of aspiration include impaired alveolar ventilation and resultant intrapulmonary shunting, which further compound the hypoxic state.
When submersion is brief, the near-drowning victim may spontaneously regain consciousness or may recover quickly following rescue. Even when victims have not aspirated fluid, they should be hospitalized for observation because respiratory symptoms may not develop for twelve to twenty-four hours. Those who have been submerged for longer periods may show varying degrees of recovery following resuscitation.
Manifestations may include acute respiratory failure, pulmonary edema (buildup of fluid in the lungs), shock acidosis, electrolyte imbalance, stupor, coma, and cardiac arrest. Damage causes cerebral edema (brain swelling) and may lead to increased intracranial pressure. Care for the patient who has suffered brain damage involves careful and frequent assessment of the patient’s neurologic status, including vital signs, pupil reaction, and reflexes.
Two other less common forms of drowning are dry drowning and secondary drowning, both of which can occur even when the person is not submerged in water. Both dry drowning and secondary drowning are precipitated by the person inhaling water. In dry drowning, inhalation of water causes the muscles in the airway to spasm, blocking the airway and preventing air from being inhaled; in secondary drowning, the inhaled water enters the lungs, resulting in pulmonary edema. Dry drowning typically occurs directly after water inhalation, while secondary drowning may occur up to twenty-four hours later.
Symptoms of both forms of drowning include trouble breathing, coughing, sleepiness or a drop in energy level, irritability or other sudden changes in behavior, chest pain, and vomiting. Parents who observe any of these symptoms after their child has spent time in water should immediately take the child to the emergency room for evaluation.
Risk Factors
Although anyone can drown, there are factors that make drowning more likely. Age and inability to swim are two of them. Indeed, the Centers for Disease Control and Prevention (CDC) states that drowning is the leading cause of preventable death in children aged one to four. American Indian or Alaska Native youth and young adults and Black people are at higher risk of fatal drowning than White people are. Individuals who have seizures, autism spectrum disorder, or heart problems are also more likely to drown. Depending on the country, being of the lower class, living in a rural area, or having little education may also increase one's susceptibility. Globally, boys and men drown more often than girls and women do and are twice as likely to die of drowning.
Other factors involve lack of protective equipment, such as barriers around swimming pools or life jackets while boating, and behaviors such as inadequate adult supervision or impaired function due to drug or alcohol use. Boating and swimming accidents account for the largest number of drownings in the adult population, and many are alcohol-related.
Treatment and Therapy
Immediate care should focus on a safe rescue of the victim. Once rescuers gain access to the victim, priorities include safe removal from the water, while maintaining spine stabilization with a board or flotation device, and initiating airway clearance and ventilatory support measures.
If hypothermia is a concern, then gentle handling of the victim is essential to prevent ventricular fibrillation. Abdominal thrusts should only be delivered if airway obstruction is suspected.
Once the victim is safely removed from the water, airway and cardiopulmonary support interventions begin. Emergency care involves cardiopulmonary resuscitation (CPR), intubation, and mechanical ventilation with 100 percent oxygen.
In the clinical setting, stomach decompression using a tube down the nose or mouth is indicated to prevent the aspiration of gastric contents and to improve breathing.
Patients who experience near-drowning require complex care to support their body systems. The full spectrum of critical care technology may be needed to manage the physiological problems and effects associated with near-drowning, including lung infection, acute respiratory distress syndrome (ARDS), and central nervous system impairment.
Metabolic acidosis results from severe hypoxia. Arterial blood gases must be monitored frequently, and sodium bicarbonate is usually administered to correct the acidosis. Coma may be induced with barbiturates and a state of hypothermia maintained for several days following the near-drowning. These interventions reduce the metabolic and oxygen demands of the brain.
Diuretics are prescribed to treat pulmonary and cerebral edema. Fluid therapy must be monitored carefully to prevent fluid overload and to promote adequate renal function.
Perspective and Prospects
In 2023, the World Health Organization (WHO) reported drowning was the third leading cause of unintentional injury death worldwide, accounting for 7 percent of all injury-related deaths in 2019. The CDC estimated that as of the early 2020s, four thousand fatal drownings and eight thousand nonfatal drownings occur each year. In 2023, Water Safety USA, a coalition of nonprofits and US government agencies, issued the country's first National Water Safety Action Plan, detailing numerous recommendations for prevention and better data collection, as part of a ten-year effort to reduce drownings.
Drowning prevention recommendations warn parents and guardians of children to be certain that everyone caring for a child understands the need for constant supervision around water. Other preventive measures include the use of safety devices and barriers around water, swimming lessons, life jackets and flotation devices while boating, and increased supervision by trained rescuers such as lifeguards.
Climate change may increase people's chances of drowning as well. Floods due to extreme weather events are becoming stronger and more common and a major driver of fatal drownings globally each year. Further, more drownings have been occurring amid hotter temperatures.
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