|Vasily Perov: The Drowned, 1867|
|Specialty||Critical care medicine|
|Symptoms||Event: Often occurs silently with a person found unconscious|
After rescue: Breathing problems, vomiting, confusion, unconsciousness
|Complications||Hypothermia, aspiration of vomit into lungs, acute respiratory distress syndrome|
|Risk factors||Alcohol use, epilepsy, low socioeconomic status, access to water, cold water shock|
|Diagnostic method||Based on symptoms|
|Differential diagnosis||Suicide, seizure, murder, hypoglycemia, heart arrhythmia|
|Prevention||Fencing pools, teaching children to swim, safe boating practices|
|Treatment||Rescue breathing, CPR, mechanical ventilation|
|Medication||Oxygen therapy, intravenous fluids, vasopressors|
|Frequency||4.5 million (2015)|
Drowning is a type of suffocation induced by the submersion of the mouth and nose in a liquid. Most instances of fatal drowning occur alone or in situations where others present are either unaware of the victim's situation or unable to offer assistance. After successful resuscitation, drowning victims may experience breathing problems, vomiting, confusion, or unconsciousness. Occasionally, victims may not begin experiencing these symptoms until several hours after they are rescued. An incident of drowning can also cause further complications for victims due to low body temperature, aspiration of vomit, or acute respiratory distress syndrome (respiratory failure from lung inflammation).
Drowning is more likely to happen when spending extended periods of time near large bodies of water. Risk factors for drowning include alcohol use, drug use, epilepsy, low socioeconomic status (which is often related to minimal or non-existent swimming skills), lack of training, and, in the case of children, a lack of supervision. Common drowning locations include natural and man-made bodies of water, bathtubs, and swimming pools.
Drowning occurs when an individual spends too much time with their nose and mouth submerged in a liquid to the point of being unable to breathe. If this is not followed by an exit to the surface, low oxygen levels and excess carbon dioxide in the blood trigger a neurological state of breathing emergency, which results in increased physical distress and occasional contractions of the vocal folds. Significant amounts of water usually only enter the lungs later in the process.
While the word "drowning" is commonly associated with fatal results, drowning may be classified into three different types: drowning that results in death, drowning that results in long-lasting health problems, and drowning that results in no health complications. Sometimes the term "near-drowning" is used in the latter cases. Among children who survive, health problems occur in about 7.5% of cases.
Steps to prevent drowning include teaching children and adults to swim and to recognise unsafe water conditions, never swimming alone, use of personal flotation devices on boats and when swimming in unfavourable conditions, limiting or removing access to water (such as with fencing of swimming pools), and exercising appropriate supervision. Treatment of victims who are not breathing should begin with opening the airway and providing five breaths of mouth-to-mouth resuscitation. Cardiopulmonary resuscitation (CPR) is recommended for a person whose heart has stopped beating and has been underwater for less than an hour.
A major contributor to drowning is the inability to swim. Other contributing factors include the state of the water itself, distance from a solid footing, physical impairment, or prior loss of consciousness. Anxiety brought on by fear of drowning or water itself can lead to exhaustion, thus increasing the chances of drowning.
Approximately 90% of drownings take place in freshwater (rivers, lakes, and a relatively small number of swimming pools); the remaining 10% take place in seawater. Drownings in other fluids are rare and often related to industrial accidents. In New Zealand's early colonial history, so many settlers died while trying to cross the rivers that drowning was called "the New Zealand death."
People have drowned in as little as 30 mm (1.2 in) of water while lying face down. Children have drowned in baths, buckets, and toilets. People who are inebriated or otherwise intoxicated can drown in puddles.
Death can occur due to complications following an initial drowning. Inhaled fluid can act as an irritant inside the lungs. Even small quantities can cause the extrusion of liquid into the lungs (pulmonary edema) over the following hours; this reduces the ability to exchange the air and can lead to a person "drowning in their own body fluid." Vomit and certain poisonous vapors or gases (as in chemical warfare) can have a similar effect. The reaction can take place up to 72 hours after the initial incident and may lead to a serious injury or death.
Many behavioral and physical factors are related to drowning:
Population groups at risk in the US are generally the old and young.[dead link]
Some additional causes of drowning can also happen during freediving activities:
Drowning can be considered as going through four stages:
Generally, in the early stages of drowning, a person holds their breath to prevent water from entering their lungs. When this is no longer possible, a small amount of water entering the trachea causes a muscular spasm that seals the airway and prevents further passage of water. If the process is not interrupted, loss of consciousness due to hypoxia is followed rapidly by cardiac arrest.
A conscious person will hold their breath (see Apnea) and will try to access air, often resulting in panic, including rapid body movement. This uses up more oxygen in the bloodstream and reduces the time until unconsciousness. The person can voluntarily hold his or her breath for some time, but the breathing reflex will increase until the person tries to breathe, even when submerged.
The breathing reflex in the human body is weakly related to the amount of oxygen in the blood but strongly related to the amount of carbon dioxide (see Hypercapnia). During an apnea, the oxygen in the body is used by the cells and excreted as carbon dioxide. Thus, the level of oxygen in the blood decreases, and the level of carbon dioxide increases. Increasing carbon dioxide levels lead to a stronger and stronger breathing reflex, up to the breath-hold breakpoint, at which the person can no longer voluntarily hold his or her breath. This typically occurs at an arterial partial pressure of carbon dioxide of 55 mm Hg but may differ significantly between people.
The breath-hold breakpoint can be suppressed or delayed, either intentionally or unintentionally. Hyperventilation before any dive, deep or shallow, flushes out carbon dioxide in the blood resulting in a dive commencing with an abnormally low carbon dioxide level: a potentially dangerous condition known as hypocapnia. The level of carbon dioxide in the blood after hyperventilation may then be insufficient to trigger the breathing reflex later in the dive.
Following this, a blackout may occur before the diver feels an urgent need to breathe. This can occur at any depth and is common in distance breath-hold divers in swimming pools. Both deep and distance free divers often use hyperventilation to flush out carbon dioxide from the lungs to suppress the breathing reflex for longer. It is important not to mistake this for an attempt to increase the body's oxygen store. The body at rest is fully oxygenated by normal breathing and cannot take on any more. Breath-holding in water should always be supervised by a second person, as by hyperventilating, one increases the risk of shallow water blackout because insufficient carbon dioxide levels in the blood fail to trigger the breathing reflex.
A continued lack of oxygen in the brain, hypoxia, will quickly render a person unconscious, usually around a blood partial pressure of oxygen of 25–30 mmHg. An unconscious person rescued with an airway still sealed from laryngospasm stands a good chance of a full recovery. Artificial respiration is also much more effective without water in the lungs. At this point, the person stands a good chance of recovery if attended to within minutes. More than 10% of drownings may involve laryngospasm, but the evidence suggests that it is not usually effective at preventing water from entering the trachea. The lack of water found in the lungs during autopsy does not necessarily mean there was no water at the time of drowning, as small amounts of freshwater are readily absorbed into the bloodstream. Hypercapnia and hypoxia both contribute to laryngeal relaxation, after which the airway is effectively open through the trachea. There is also bronchospasm and mucous production in the bronchi associated with laryngospasm, and these may prevent water entry at terminal relaxation.
The hypoxemia and acidosis caused by asphyxia in drowning affect various organs. There can be central nervous system damage, cardiac arrhythmia, pulmonary injury, reperfusion injury, and multiple-organ secondary injury with prolonged tissue hypoxia.
A lack of oxygen or chemical changes in the lungs may cause the heart to stop beating. This cardiac arrest stops the flow of blood and thus stops the transport of oxygen to the brain. Cardiac arrest used to be the traditional point of death, but at this point, there is still a chance of recovery. The brain cannot survive long without oxygen, and the continued lack of oxygen in the blood, combined with the cardiac arrest, will lead to the deterioration of brain cells, causing first brain damage and eventually brain death from which recovery is generally considered impossible. The brain will die after approximately six minutes without oxygen at normal body temperature, but hypothermia of the central nervous system may prolong this.
The extent of central nervous system injury to a large extent determines the survival and long term consequences of drowning, In the case of children, most survivors are found within 2 minutes of immersion, and most fatalities are found after 10 minutes or more.
If water enters the airways of a conscious person, the person will try to cough up the water or swallow it, often inhaling more water involuntarily. When water enters the larynx or trachea, both conscious and unconscious people experience laryngospasm, in which the vocal cords constrict, sealing the airway. This prevents water from entering the lungs. Because of this laryngospasm, in the initial phase of drowning, water generally enters the stomach, and very little water enters the lungs. Though laryngospasm prevents water from entering the lungs, it also interferes with breathing. In most people, the laryngospasm relaxes sometime after unconsciousness, and water can then enter the lungs, causing a "wet drowning." However, about 7–10% of people maintain this seal until cardiac arrest. This has been called "dry drowning", as no water enters the lungs. In forensic pathology, water in the lungs indicates that the person was still alive at the point of submersion. An absence of water in the lungs may be either a dry drowning or indicates a death before submersion.
Aspirated water that reaches the alveoli destroys the pulmonary surfactant, which causes pulmonary edema and decreased lung compliance, compromising oxygenation in affected parts of the lungs. This is associated with metabolic acidosis, secondary fluid, and electrolyte shifts. During alveolar fluid exchange, diatoms present in the water may pass through the alveolar wall into the capillaries to be carried to internal organs. The presence of these diatoms may be diagnostic of drowning.
Of people who have survived drowning, almost one-third will experience complications such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). ALI/ARDS can be triggered by pneumonia, sepsis, and water aspiration. These conditions are life-threatening disorders that can result in death if not treated promptly. During drowning, aspirated water enters the lung tissues, causes a reduction in alveolar surfactant, obstructs ventilation, and triggers a release of inflammatory mediators which ultimately results in hypoxia. Specifically, upon reaching the alveoli, hypotonic liquid found in freshwater dilutes pulmonary surfactant, destroying the substance. Comparatively, aspiration of hypertonic seawater draws liquid from the plasma into the alveoli and similarly causes damage to surfactant by disrupting the alveolar-capillary membrane. Still, there is no clinical difference between salt and freshwater drowning. Once someone has reached definitive care, supportive care strategies such as mechanical ventilation can help to reduce the complications of ALI/ARDS.
Whether a person drowns in freshwater or salt water makes no difference in respiratory management or its outcome. People who drown in freshwater may experience worse hypoxemia early in their treatment, however, this initial difference is short-lived and the management of both fresh water and salt water drowning is essentially the same.
Submerging the face in water cooler than about 21 °C (70 °F) triggers the diving reflex, common to air-breathing vertebrates, especially marine mammals such as whales and seals. This reflex protects the body by putting it into energy-saving mode to maximise the time it can stay underwater. The strength of this reflex is greater in colder water and has three principal effects:
The reflex action is automatic and allows both a conscious and an unconscious person to survive longer without oxygen underwater than in a comparable situation on dry land. The exact mechanism for this effect has been debated and may be a result of brain cooling similar to the protective effects seen in people who are treated with deep hypothermia.
The actual cause of death in cold or very cold water is usually lethal bodily reactions to increased heat loss and to freezing water, rather than any loss of core body temperature. Of those who die after plunging into freezing seas, around 20% die within 2 minutes from cold shock (uncontrolled rapid breathing and gasping causing water inhalation, a massive increase in blood pressure and cardiac strain leading to cardiac arrest, and panic), another 50% die within 15 – 30 minutes from cold incapacitation (loss of use and control of limbs and hands for swimming or gripping, as the body 'protectively' shuts down the peripheral muscles of the limbs to protect its core), and exhaustion and unconsciousness cause drowning, claiming the rest within a similar time. A notable example of this occurred during the sinking of the Titanic, in which most people who entered the −2 °C (28 °F) water died within 15–30 minutes.
[S]omething that almost no one in the maritime industry understands. That includes mariners [and] even many (most) rescue professionals: It is impossible to die from hypothermia in cold water unless you are wearing flotation, because without flotation – you won’t live long enough to become hypothermic.— Mario Vittone, lecturer and author in water rescue and survival
Submersion into cold water can induce cardiac arrhythmias (abnormal heart rates) in healthy people, sometimes causing strong swimmers to drown. The physiological effects caused by the diving reflex conflict with the body's cold shock response, which includes a gasp and uncontrollable hyperventilation leading to aspiration of water. While breath-holding triggers a slower heart rate, cold shock activates tachycardia, an increase in heart rate. It is thought that this conflict of these nervous system responses may account for the arrhythmias of cold water submersion.
Heat transfers very well into water, and body heat is therefore lost extremely quickly in water compared to air, even in merely 'cool' swimming waters around 70 °F (~20 °C). A water temperature of 10 °C (50 °F) can lead to death in as little as one hour, and water temperatures hovering at freezing can lead to death in as little as 15 minutes. This is because cold water can have other lethal effects on the body. Hence, hypothermia is not usually a reason for drowning or the clinical cause of death for those who drown in cold water.
Upon submersion into cold water, remaining calm and preventing loss of body heat is paramount. While awaiting rescue, swimming or treading water should be limited to conserve energy, and the person should attempt to remove as much of the body from the water as possible; attaching oneself to a buoyant object can improve the chance of survival should unconsciousness occur.
Hypothermia (and cardiac arrest) presents a risk for survivors of immersion. This risk increases if the survivor—feeling well again—tries to get up and move, not realizing their core body temperature is still very low and will take a long time to recover.
Most people who experience cold-water drowning do not develop hypothermia quickly enough to decrease cerebral metabolism before ischemia and irreversible hypoxia occur. The neuroprotective effects appear to require water temperatures below about 5 °C (41 °F).
The World Health Organization in 2005 defined drowning as "the process of experiencing respiratory impairment from submersion/immersion in liquid." This definition does not imply death or even the necessity for medical treatment after removing the cause, nor that any fluid enters the lungs. The WHO further recommended that outcomes should be classified as death, morbidity, and no morbidity. There was also consensus that the terms wet, dry, active, passive, silent, and secondary drowning should no longer be used.
Experts differentiate between distress and drowning.
Forensic diagnosis of drowning is considered one of the most difficult in forensic medicine. External examination and autopsy findings are often non-specific, and the available laboratory tests are often inconclusive or controversial. The purpose of an investigation is generally to distinguish whether the death was due to immersion or whether the body was immersed postmortem. The mechanism in acute drowning is hypoxemia and irreversible cerebral anoxia due to submersion in liquid.
Drowning would be considered a possible cause of death if the body was recovered from a body of water, near a fluid that could plausibly have caused drowning, or found with the head immersed in a fluid. A medical diagnosis of death by drowning is generally made after other possible causes of death have been excluded by a complete autopsy and toxicology tests. Indications of drowning are seldom completely unambiguous and may include bloody froth in the airway, water in the stomach, cerebral edema and petrous or mastoid hemorrhage. Some evidence of immersion may be unrelated to the cause of death, and lacerations and abrasions may have occurred before or after immersion or death.
Diatoms should normally never be present in human tissue unless water was aspirated. Their presence in tissues such as bone marrow suggests drowning; however, they are present in soil and the atmosphere, and samples may easily be contaminated. An absence of diatoms does not rule out drowning, as they are not always present in water. A match of diatom shells to those found in the water may provide supporting evidence of the place of death. Drowning in saltwater can leave significantly different concentrations of sodium and chloride ions in the left and right chambers of the heart, but they will dissipate if the person survived for some time after the aspiration, or if CPR was attempted, and have been described in other causes of death.
Most autopsy findings relate to asphyxia and are not specific to drowning. The signs of drowning are degraded by decomposition. Large amounts of froth will be present around the mouth and nostrils and in the upper and lower airways in freshly drowned bodies. The volume of froth is generally much greater in drowning than from other origins. Lung density may be higher than normal, but normal weights are possible after cardiac arrest or vasovagal reflex. The lungs may be overinflated and waterlogged, filling the thoracic cavity. The surface may have a marbled appearance, with darker areas associated with collapsed alveoli interspersed with paler aerated areas. Fluid trapped in the lower airways may block the passive collapse that is normal after death. Hemorrhagic bullae of emphysema may be found. These are related to the rupture of alveolar walls. These signs, while suggestive of drowning, are not conclusive.
It is estimated that more than 85% of drownings could be prevented by supervision, training in water skills, technology, and public education.
The concept of water safety involves the procedures and policies that are directed to prevent people from drowning or from becoming injured in water.
Further information: Drowning § Pathophysiology
The time a person can safely stay underwater depends on many factors, including energy consumption, number of prior breaths, physical condition, and age. An average person can last between one and three minutes before falling unconscious and around ten minutes before dying. In an unusual case, a person was resuscitated after 65 minutes underwater.
When a person is drowning or a swimmer becomes missing, a fast water rescue may become necessary to take that person out of the water as soon as possible. Drowning is not necessarily violent or loud, with splashing and cries; it can be silent.
Rescuers should avoid endangering themselves unnecessarily; whenever it is possible, they should assist from a safe ground position, such as a boat, a pier, or any patch of land near the victim. The fastest way to assist is to throw a buoyant object (such as a lifebuoy). It is very important to avoid aiming directly at the victim, since even the lightest lifebuoys weight over 2 kilograms, and can stun, injure or even render a person unconscious if they impact on the head. Alternatively, one could try to pull the victim out of the water by holding out an object to grasp. Some examples include: ropes, oars, poles, one's own arm, a hand, etc. This carries the risk of the rescuer being pulled into the water by the victim, so the rescuer must take a firm stand, lying down, as well as securing to some stable point. Alternatively, there are modern flying drones that drop life jackets.
Bystanders should immediately call for help. A lifeguard should be called, if present. If not, emergency medical services and paramedics should be contacted as soon as possible. Less than 6% of people rescued by lifeguards need medical attention, and only 0.5% need CPR. The statistics worsen when rescues are made by bystanders.
If lifeguards or paramedics are unable to be called, bystanders must rescue the drowning person. Alternatively, there are small floating robots that can reach the victim, as human rescue carries a risk for the rescuer, who could be drowned. Death of the would-be rescuer can happen because of the water conditions, the instinctive drowning response of the victim, the physical effort, and other problems.
After reaching the victim, first contact made by the rescuer is important. A drowning person in distress is likely to cling to the rescuer in an attempt to stay above the water surface, which could submerge the rescuer in the process. To avoid this, it is recommended that the rescuer approaches the panicking person with a buoyant object or extending a hand, so the victim has something to grasp. It can even be appropriate to approach from behind, taking one of the victim's arms, and pressing it against the victim's back to restrict unnecessary movement. Communication is also important.
If the victim clings to the rescuer and the rescuer cannot control the situation, a possibility is to dive underwater (as drowning people tend to move in the opposite direction, seeking the water surface) and consider a different approach to help the drowning victim.
It is possible that the victim has already sunk beneath the water surface. If this has happened, the rescue requires caution, as the victim could be conscious and cling to the rescuer underwater. The rescuer must bring the victim to the surface by grabbing either (or both) of the victim's arms and swimming upward, which may entice the victim to travel in the same direction, thus making the task easier, especially in the case of an unconscious victim. Should the victim be located in deeper waters (or simply complicates matters too much) the rescuer should dive, take the victim from behind, and ascend vertically to the water surface holding the victim.
After a successful contact with the victim, any ballast (such as weight belt) should be discarded.
Finally, the victim must be taken out of the water, which is achieved by a towing maneuver. This is commonly done placing the victim body in a face-up horizontal position, passing one hand under the victim's armpit to then grab the jaw with it, and towing by swimming backwards. The victim's mouth and nose must be kept above the water surface.
If the person is cooperative, the towing may be done in a similar fashion with the hands going under the victim's armpits. Other styles of towing are possible, but all of them keeping the victim's mouth and nose above the water.
Unconscious people may be pulled in an easier way: pulling on a wrist or on the shirt while they are in a face-up horizontal position. Victims with suspected spinal injuries can require a more specific grip and special care, and a backboard (spinal board) may be needed for their rescue.
For unconscious people, an in-water resuscitation could increase the chances of survival by a factor of about three, but this procedure requires both medical and swimming skills, and it becomes impractical to send anyone besides the rescuer to execute that task. Chest compressions require a suitable platform, so an in-water assessment of circulation is pointless. If the person does not respond after a few breaths, cardiac arrest may be assumed, and getting them out of the water becomes a priority.
The checks for responsiveness and breathing are carried out with the person horizontally supine. If unconscious but breathing, the recovery position is appropriate.
If not breathing, rescue ventilation is necessary. Drowning can produce a gasping pattern of apnea while the heart is still beating, and ventilation alone may be sufficient. The airway-breathing-circulation (ABC) sequence should be followed, rather than starting with compressions as is typical in cardiac arrest, because the basic problem is lack of oxygen. If the victim is not a baby, it is recommended to start with 5 normal rescue breaths, as the initial ventilation may be difficult because of water in the airways, which can interfere with effective alveolar inflation. Thereafter, a continual sequence of 2 rescue breaths and 30 chest compressions is applied. This alternation is repeated until vital signs are re-established, the rescuers are unable to continue, or advanced life support is available.
For babies (very small sized infants), the procedure is slightly modified. In each sequence of rescue breaths (the 5 initial breaths, and the further series of 2 breaths), the rescuer's mouth covers the baby's mouth and nose simultaneously (because a baby's face is too small). Besides, the intercalated series of 30 chest compressions are applied by pressing with only two fingers (due to the body of the babies is more fragile) on the chest bone (approximately on the lower part).
Attempts to actively expel water from the airway by abdominal thrusts, Heimlich maneuver or positioning head downwards should be avoided as there is no obstruction by solids, and they delay the start of ventilation and increase the risk of vomiting, with a significantly increased risk of death, as the aspiration of stomach contents is a common complication of resuscitation efforts.
Treatment for hypothermia may also be necessary. However, in those who are unconscious, it is recommended their temperature not be increased above 34 degrees C. Because of the diving reflex, people submerged in cold water and apparently drowned may revive after a relatively long period of immersion. Rescuers retrieving a child from water significantly below body temperature should attempt resuscitation even after protracted immersion.
People with a near-drowning experience who have normal oxygen levels and no respiratory symptoms should be observed in a hospital environment for a period of time to ensure there are no delayed complications. The target of ventilation is to achieve 92% to 96% arterial saturation and adequate chest rise. Positive end-expiratory pressure will generally improve oxygenation. Drug administration via peripheral veins is preferred over endotracheal administration. Hypotension remaining after oxygenation may be treated by rapid crystalloid infusion. Cardiac arrest in drowning usually presents as asystole or pulseless electrical activity. Ventricular fibrillation is more likely to be associated with complications of pre-existing coronary artery disease, severe hypothermia, or the use of epinephrine or norepinephrine.
While surfactant may be used, no high-quality evidence exist that looks at this practice. Extracorporeal membrane oxygenation may be used in those who cannot be oxygenated otherwise. Steroids are not recommended.
|Drowning outcomes (after hospital treatment)|
|Duration of submersion||Risk of death or poor outcomes|
|>25 min||nearly 100%|
|Signs of brain-stem injury predict death or severe neurological consequences|
People who have drowned who arrive at a hospital with spontaneous circulation and breathing usually recover with good outcomes. Early provision of basic and advanced life support improve the probability of a positive outcome.
A longer duration of submersion is associated with a lower probability of survival and a higher probability of permanent neurological damage.
Contaminants in the water can cause bronchospasm and impaired gas exchange and can cause secondary infection with delayed severe respiratory compromise.
Low water temperature can cause ventricular fibrillation, but hypothermia during immersion can also slow the metabolism, allowing longer hypoxia before severe damage occurs. Hypothermia that reduces brain temperature significantly can improve the outcome. A reduction of brain temperature by 10 °C decreases ATP consumption by approximately 50%, which can double the time the brain can survive.
The younger the person, the better the chances of survival. In one case, a child submerged in cold (37 °F (3 °C)) water for 66 minutes was resuscitated without apparent neurological damage. However, over the long term significant deficits were noted, including a range of cognitive difficulties, particularly general memory impairment, although recent magnetic resonance imaging (MRI) and magnetoencephalography (MEG) were within normal range.
Drowning is a major worldwide cause of death and injury in children. An estimate of about 20% of non-fatal drowning victims may result in varying degrees of ischemic and/or hypoxic brain injury. Hypoxic injuries refers to a lack or absence of oxygen in certain organs or tissues. Ischemic injuries on the other hand refers inadequate blood supply to certain organs or part of the body. These injuries can lead to an increased risk of long-term morbidity. Prolonged hypothermia and hypoxemia from nonfatal submersion drowning can result in cardiac dysrhythmias such as ventricular fibrillation, sinus bradycardia, or atrial fibrillation. Long-term neurological outcomes of drowning cannot be predicted accurately during the early stages of treatment. Although survival after long submersion times, mostly by young children, has been reported, many survivors will remain severely and permanently neurologically compromised after much shorter submersion times. Factors affecting the probability of long-term recovery with mild deficits or full function in young children include the duration of submersion, whether advanced life support was needed at the accident site, the duration of cardiopulmonary resuscitation, and whether spontaneous breathing and circulation are present on arrival at the emergency room. Prolonged submersion in water for more than 5–10 minutes usually leads to poorer prognosis.
Data on the long-term outcome are scarce and unreliable. Neurological examination at the time of discharge from the hospital does not accurately predict long-term outcomes. Some people with severe brain injury who were transferred to other institutions died months or years after the drowning and are recorded as survivors. Nonfatal drownings have been estimated as two to four times more frequent than fatal drownings.
Long-term effects of nonfatal drowning mainly include damage to major organs such as the brain, lungs, and kidneys. Prolonged submersion time is highly attributed to hypoxic ischemic brain injury in susceptible areas of the brain such as the hippocampus, insular cortex, and/or basal ganglia. Severity in hypoxic ischemic damage of these brain structures corresponds to the severity in global damage to areas of the cerebral cortex. The cerebral cortex is a brain structure that is responsible for language, memory, learning, emotion, intelligence, and personality. Global damage to the cerebral cortex can affect one or more of its primary function. Treatment of pulmonary complication from drowning is highly dependent on the amount of lung injury that occurred during the incident. These lung injuries can be contributed by water aspiration and also irritants present in the water such as microbial pathogens leading to complications such as lung infection that can develop in adult respiratory disease syndrome later on in life. Some literature suggests that occurrences of drowning can lead to acute kidney injury from lack of blood flow and oxygenation due to shock and global hypoxia. These kidney injury can cause irreversible damage to the kidneys and may require long-term treatment such as renal replacement therapy.
Children are overrepresented in drowning statistics, with children aged 0–4 years old having the highest number of deaths due to unintentional downing. In 2019 alone, 32,070 children between the ages 1–4 years old died as a result of unintentional drowning, equating to an age-adjusted fatality of 6.04 per 100,000 children. Infants are particularly vulnerable because while their mobility develops quickly, their perception concerning their ability for locomotion between surfaces develops slower. An infant can have full control of their movements, but simply won't recognize that water does not provide the same support for crawling as hardwood floors would. An infant’s capacity for movement needs to be met with an appropriate perception of surfaces of support (and avoidance of surfaces that do not support locomotion) to avoid drowning. By crawling and interacting with their environment, infants learn to distinguish surfaces offering support for locomotion from those that do not, and their perception of surface characteristics will improve, as well as their perception of falls risk, over several weeks.
In 2019 alone, roughly 236,000 people died from drowning, thereby causing it to be the third leading cause of unintentional death globally trailing only traffic injuries and falls.
In many countries, drowning is one of the main causes of preventable death for children under 12 years old. In the United States in 2006, 1100 people under 20 years of age died from drowning. The United Kingdom has 450 drownings per year, or 1 per 150,000, whereas in the United States, there are about 6,500 drownings yearly, around 1 per 50,000. In Asia suffocation and drowning were the leading causes of preventable death for children under five years of age; a 2008 report by UNICEF found that in Bangladesh, for instance, 46 children drown each day.
Due to a generally increased likelihood for risk-taking, males are four times more likely to have submersion injuries.
In the fishing industry, the largest group of drownings is associated with vessel disasters in bad weather, followed by man-overboard incidents and boarding accidents at night, either in foreign ports or under the influence of alcohol. Scuba diving deaths are estimated at 700 to 800 per year, associated with inadequate training and experience, exhaustion, panic, carelessness, and barotrauma.
Deaths due to drowning is high in the South Asian region with India, China, Pakistan and Bangladesh accounting for up to 52% of the global deaths. Death due to drowning is known to be high in the Sundarbans region in West Bengal and in Bihar.
According to Daily Times in rural Pakistan while boats are preferred mode of transport where available same time, due to influence of female modesty culture in Pakistan generally women are not encouraged in swimming; in a 2022 July tragedy at Sadiqabad when a boat carrying 100 people capsized in Indus river, many could rescue themselves but 19 women were confirmed dead by drowning since they could not save themselves by swimming.
In lower income countries, cases of drowning and deaths caused by drowning are under reported and data collection is limited. In spite of this, many low-income countries in Africa still exhibit some of the highest rates of drowning, with incidence rates calculated from population based studies across 15 different countries (Egypt, Ethiopia, Kenya, Uganda, Tanzania, Malawi, Zimbabwe, South Africa, Nigeria, Ghana, Burkina Faso, Ghana, Guinea, Cote d'Ivoire, and the Gambia) ranging from 0.33 per 100,000 population to 502 per 100,000 population. Potential risk factors include young age, male gender, having to commute across or work on the water (e.g. Fishermen), quality and carrying capacity of the boat, and poor weather.
In the United States, drowning is the second leading cause of death (after motor vehicle accidents) in children 12 and younger.
People who drown are more likely to be male, young, or adolescent. There is a racial disparity found in drowning incidents. According to CDC data collected from 1999 to 2019, drowning rates among Native Americans was 2 times higher than non-Hispanic whites while the rate among African-Americans was 1.5 times higher. Surveys indicate that 10% of children under 5 have experienced a situation with a high risk of drowning. Worldwide, about 175,000 children die through drowning every year. The causes of drowning cases in the US from 1999 to 2006 were as follows:
|31.0%||Drowning and submersion while in natural water|
|27.9%||Unspecified drowning and submersion|
|14.5%||Drowning and submersion while in swimming pool|
|9.4%||Drowning and submersion while in bathtub|
|7.2%||Drowning and submersion following fall into natural water|
|6.3%||Other specified drowning and submersion|
|2.9%||Drowning and submersion following fall into swimming pool|
|0.9%||Drowning and submersion following fall into bathtub|
According to the US National Safety Council, 353 people ages 5 to 24 drowned in 2017.
The word "drowning"—like "electrocution"—was previously used to describe fatal events only. Occasionally, that usage is still insisted upon, though the medical community's consensus supports the definition used in this article. Several terms related to drowning which have been used in the past are also no longer recommended. These include:
Dry drowning is a term that has never had an accepted medical definition and that is currently medically discredited. Following the 2002 World Congress on Drowning in Amsterdam, a consensus definition of drowning was established: it is the "process of experiencing respiratory impairment from submersion/immersion in liquid." This definition resulted in only three legitimate drowning subsets: fatal drowning, non-fatal drowning with illness/injury, and non-fatal drowning without illness/injury. In response, major medical consensus organizations have adopted this definition worldwide and have officially discouraged any medical or publication use of the term "dry drowning". Such organizations include the International Liaison Committee on Resuscitation, the Wilderness Medical Society, the American Heart Association, the Utstein Style system, the International Lifesaving Federation, the International Conference on Drowning, Starfish Aquatics Institute, the American Red Cross, the Centers for Disease Control and Prevention (CDC), the World Health Organization and the American College of Emergency Physicians.
Drowning experts have recognized that the resulting pathophysiology of hypoxemia, acidemia, and eventual death is the same whether water entered the lung or not. As this distinction does not change management or prognosis but causes significant confusion due to alternate definitions and misunderstandings, it is generally established that pathophysiological discussions of "dry" versus "wet" drowning are not relevant to drowning care.
"Dry drowning" is frequently cited in the news with a wide variety of definitions. and is often confused with the equally inappropriate and discredited term "secondary drowning" or "delayed drowning". Various conditions including spontaneous pneumothorax, chemical pneumonitis, bacterial or viral pneumonia, head injury, asthma, heart attack, and chest trauma have been misattributed to the erroneous terms "delayed drowning," "secondary drowning," and "dry drowning." Currently, there has never been a case identified in the medical literature where a person was observed to be without symptoms and who died hours or days later as a direct result of drowning alone.
Main article: Execution by drowning
In Europe, drowning was used as capital punishment. During the Middle Ages, a sentence of death was read using the words cum fossa et furca, or "with pit and gallows".
Drowning survived as a method of execution in Europe until the 17th and 18th centuries. England had abolished the practice by 1623, Scotland by 1685, Switzerland in 1652, Austria in 1776, Iceland in 1777, and Russia by the beginning of the 1800s. France revived the practice during the French Revolution (1789–1799) and it was carried out by Jean-Baptiste Carrier at Nantes.
There is insufficient evidence to recommend for or against the use of oxygen by the first aid provider.
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