(Fatal Drowning; Nonfatal Drowning)

ByDavid Richards, MD, University of Colorado School of Medicine
Reviewed/Revised Jan 2023
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Drowning is respiratory impairment resulting from submersion in a liquid medium. It can be nonfatal (previously called near drowning) or fatal. Drowning results in hypoxia, which can damage multiple organs, particularly the brain. Treatment is supportive, including reversal of respiratory arrest and cardiac arrest, hypoxia, hypoventilation, and hypothermia.

Drowning is among the top 10 causes of mortality for children and young people worldwide. In 2020 in the US, drowning was the leading cause of injury mortality in children aged 1 to 4 years and was second only to motor vehicle collisions for children aged 5 to 9 years; drowning also was among the top 10 causes of unintentional death in all ages under 55 years (1). Groups at high risk of drowning death include the following:

  • Children from African American, Native American, immigrant, or impoverished families (2)

  • Children who have not received formal swimming lessons and are unsupervised around water (3, 4)

  • Males (80% of victims over age 1 year are male)

  • People who have used alcohol or other drugs that affect judgment and alertness

  • People with conditions that cause temporary incapacitation (eg, epilepsy [5], which is associated with a 20 times increased chance of drowning among children and adolescents)

  • People with arrhythmogenic cardiac disorders, including long QT syndrome (swimming can trigger arrhythmias that cause unexplained drowning in people with such disorders)

  • People who engage in dangerous underwater breath-holding behaviors (DUBBs)

Drowning is common in pools, hot tubs, and natural water settings, and, among infants and toddlers, in toilets, bathtubs, and buckets of water or cleaning fluids.

Nonfatal drownings are more common than fatal drownings; for every child that dies of drowning, approximately 7 receive emergency department care. About 40% of those treated in emergency departments require admission to the hospital (6).

Pathophysiology of Drowning


Hypoxia is the major insult in drowning, affecting the brain, heart, and other tissues; respiratory arrest followed by cardiac arrest may occur. Brain hypoxia may cause cerebral edema and, occasionally, permanent neurologic sequelae. Generalized tissue hypoxia may cause metabolic acidosis. Immediate hypoxia results from aspiration of fluid or gastric contents, acute reflex laryngospasm (previously called dry drowning), or both. Lung injury due to aspiration or hypoxia itself may cause delayed hypoxia (previously called secondary drowning). Aspiration, especially with particulate matter or chemicals, may cause chemical pneumonitis or secondary bacterial pneumonia and may impair alveolar secretion of surfactant, resulting in patchy atelectasis. Extensive atelectasis may make the affected areas of the lungs stiff, noncompliant, and poorly ventilated, potentially causing respiratory failure with hypercapnia and respiratory acidosis. Perfusion of poorly ventilated areas of the lungs (V/Q mismatch) worsens hypoxia. Alveolar hypoxia may cause noncardiogenic pulmonary edema.


Exposure to cold water induces systemic hypothermia, which can be a significant problem. However, hypothermia can be protective by stimulating the mammalian diving reflex, slowing the heart rate, and constricting the peripheral arteries, shunting oxygenated blood away from the extremities and the gut to the heart and brain. Also, hypothermia decreases the oxygen needs of tissues, possibly prolonging survival and delaying the onset of hypoxic tissue damage. The diving reflex and overall clinically protective effects of cold water are usually greatest in young children.

Fluid aspiration

Laryngospasm often limits the volume of fluid aspirated. Distinction between freshwater and seawater drowning was once considered important due to the potential electrolyte shifts, hemolysis, and fluid compartment shifting that possibly could occur. However, studies have shown that in most patients, too little liquid is aspirated to have these effects. Aspiration can lead to pneumonia, sometimes with anaerobic or fungal pathogens, and pulmonary edema.

Dangerous underwater breath-holding behaviors (DUBBs)

Dangerous underwater breath-holding behaviors are practiced mostly by healthy young men (often good swimmers) trying to prolong their capacity to remain submerged. There are 3 described types of DUBB:

  • Intentional hyperventilation—blowing off carbon dioxide before submerged swimming, thereby delaying central hypercarbic ventilatory responses

  • Hypoxic training—extending capacity for underwater distance swimming or breath-holding

  • Static apnea—breath-holding for as long as possible while submerged and motionless, including as a game

In DUBBs, while submerged, hypoxia occurs first, followed by loss of consciousness (hypoxic blackout, breath-hold blackout) and then drowning.

Associated injuries

Skeletal, soft-tissue, head, and internal injuries may occur, particularly among surfers, water skiers, boaters, flood victims, and occupants of submerged vehicles. People who dive into shallow water may sustain cervical and other spine injuries (which may be the cause of drowning).

General references

  1. 1. Centers for Disease Control and Prevention. Injury Prevention & Control : Leading causes of death and injury, United States, 2020. Accessed October 27, 2022.

  2. 2. Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report: Racial/Ethnic disparities in fatal unintentional drowning among persons aged 29 years – United States 1999-2010. MMWR 63:421-426, 2014.

  3. 3. Day G, Holck P, Strayer H, et al:  Disproportionately higher unintentional injury mortality among Alaska Native people, 2006-2015.  Int J Circumpolar Health 77(1):1422671, 2018. doi: 10.1080/22423982.2017.1422671

  4. 4. Felton H, Myers J, Liu G, et al:  Unintentional, non-fatal drowning of children: US trends and racial/ethnic disparities. BMJ Open 5(12):e008444, 2015. doi: 10.1136/bmjopen-2015-008444

  5. 5. Sillanpää M, Shinnar S: SUDEP and other causes of mortality in childhood-onset epilepsy. Epilepsy Behav 28(2):249-255, 2013. doi: 10.1016/j.yebeh.2013.04.016

  6. 6. Centers for Disease Control and Prevention. Drowning Prevention: Drowning facts. Adapted from Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. Web-based Injury Statistics Query and Reporting System (WISQARS). Accessed August 10, 2022.

Symptoms and Signs of Drowning

During drowning, panic and air hunger occur. Children who are unable to swim may become submerged in < 1 minute, more rapidly than adults. After rescue, anxiety, vomiting, wheezing, and altered consciousness are common. Patients may have respiratory failure with tachypnea, intercostal retractions, or cyanosis. Respiratory symptoms are sometimes delayed for up to 8 hours after submersion. Patients may have symptoms due to injuries or exacerbations of underlying disorders.

Pearls & Pitfalls

  • Sometimes respiratory symptoms and hypoxia are delayed for up to 8 hours after submersion.

Diagnosis of Drowning

  • Clinical evaluation

  • For concomitant injuries, imaging studies as indicated

  • Pulse oximetry and, if results are abnormal or if respiratory symptoms and signs are present, arterial blood gases (ABG) and chest x-ray

  • Core temperature measurement to rule out hypothermia

  • Evaluation for causative or contributing disorders (eg, seizure, hypoglycemia, myocardial infarction, intoxication, injury)

  • Ongoing monitoring as indicated for delayed respiratory complications

Most people are found in or near water, making the diagnosis obvious clinically. Resuscitation, if indicated, should precede completion of the diagnostic assessment. Cervical spine injury is considered, and the spine is immobilized in patients whose mechanism of injury potentially involves diving or trauma. Secondary head injury and conditions that may have contributed to drowning (eg, hypoglycemia, myocardial infarction, stroke, intoxication, arrhythmia) are considered.

All patients undergo assessment of oxygenation by oximetry or, if results are abnormal or if there are respiratory symptoms or signs, arterial blood gas (ABG) and chest x-ray. Because respiratory symptoms may be delayed, even asymptomatic patients are transported to the hospital and observed for several hours.

In patients with symptoms or a history of prolonged submersion, core body temperature is measured, electrocardiography and serum electrolytes are obtained, and continuous oximetry and cardiac monitoring are done. Patients with possible cervical spine injury undergo cervical spine imaging.

Patients with altered consciousness undergo head CT. Any other suspected predisposing or secondary conditions are evaluated with appropriate testing (eg, fingerstick glucose for hypoglycemia, electrocardiography for myocardial infarction, cardiac monitoring for arrhythmia, evaluation for intoxication). Patients who drown without apparent risk factors are evaluated for long QT syndrome, torsades de pointes ventricular tachycardia, and any other suspected arrhythmogenic cardiac disorders. In patients with pulmonary infiltrates, bacterial or fungal pneumonia is differentiated from chemical pneumonitis and pulmonary edema using blood cultures and sputum Gram stain and culture. If indicated (eg, bacterial or fungal pneumonia is suspected but the pathogen cannot be otherwise identified), bronchial washings are obtained for testing, including culture.

Clinical Calculators

Treatment of Drowning

  • Resuscitation

  • Correction of oxygen and carbon dioxide levels and other physiologic abnormalities

  • Intensive respiratory support

Treatment aims to correct cardiac arrest, hypoxia, hypoventilation, hypothermia, and other physiologic insults.

Resuscitation after drowning

In apneic patients, rescue breathing is started immediately—in the water, if necessary. If spinal immobilization is necessary, it is done in a neutral position, and rescue breathing is done using a jaw thrust without head tilt or chin lift. Emergency medical services are called. If the patient does not respond to rescue breathing, cardiac compressions are started, followed by advanced cardiac life support. Although the 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation (CPR) recommend chest compressions as the first step in resuscitation of patients in cardiac arrest, drowning is an exception to this recommendation and rescue breathing is started first (1). Attempts to remove water from the lungs are avoided because they delay ventilation and increase the risk of vomiting. Oxygenation, endotracheal intubation, or both should proceed as soon as possible. Hypothermic patients are warmed as soon as possible. Immediate treatment measures may include removing clothing, drying, and insulation. Prolonged resuscitation efforts should be considered especially in young patients involved in cold water drownings.

Pearls & Pitfalls

  • Avoid attempts to remove water from the lungs; this only delays ventilation and increases risk of vomiting.

Hospital care for drowning patients

All hypoxic or moderately symptomatic patients are hospitalized. In the hospital, supportive treatment continues, aimed primarily at achieving acceptable arterial oxygen and carbon dioxide levels. Mechanical ventilation may be necessary. Patients are initially given 100% oxygen; the concentration is titrated lower based on arterial blood gas (ABG) results. Positive end-expiratory pressure ventilation is sometimes necessary to help expand or maintain patency of alveoli to maintain adequate oxygenation. Pulmonary support may be necessary for hours or days. If adequate oxygenation is impossible despite maximizing ventilator settings, extracorporeal membrane oxygenation may be considered. Nebulized beta-2 agonists may help reduce bronchospasm and wheezing. Surfactant administration may be helpful in critically ill patients with significant lung compliance issues after drowning, although no large clinical trials have addressed this.

Core body temperature is monitored, and hypothermia is treated. Fluids or electrolytes are rarely required to correct significant volume or electrolyte imbalances. Fluid restriction is rarely indicated unless pulmonary or cerebral edema occurs. Concomitant injuries and disorders (eg, head or cervical injury, seizure, arrhythmia) may also require treatment. Patients who have persistent altered mental status despite correction of respiratory compromise should be evaluated for other injuries (eg, occult seizures, intracranial injury). Patients with pneumonia, confirmed by results of sputum testing and/or blood cultures, are treated with antibiotics that target identified or suspected organisms. Corticosteroids are not used.

Discharge of drowning patients

Patients with mild symptoms, clear lungs, and normal mentation and oxygenation should be observed in the emergency department for at least 8 hours (2, 3). If symptoms resolve and the examination and oxygenation remain normal, patients can be discharged with instructions to return if symptoms recur.

Treatment references

  1. 1. Panchal AR, Bartos JA, Cabanas JG, et al: Adult Basic and Advanced Life Support Writing Group. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 142(16_suppl_2):S366-S468, 2020. doi: 10.1161/CIR.0000000000000916

  2. 2. Brennan C, Hong T, Wang VJ: Predictors of safe discharge for pediatric drowning patients in the emergency department. Am J Emerg Med 2018, 36(9):1619-1623. doi: 10.1016/j.ajem.2018.01.050

  3. 3. Shenoi RP, Allahabadi S, Rubalcava DM, et al: The pediatric submersion score predicts children at low risk for injury following submersions. Acad Emerg Med 24(12):1491-1500, 2017. doi: 10.1111/acem.13278

Prognosis for Drowning

Factors that increase the chance of surviving submersion without permanent injury include the following:

  • Rapid institution of resuscitation (most important)

  • Brief duration of submersion

  • Cold water temperature

  • Young age

  • Absence of underlying medical conditions, secondary trauma, and aspiration of particulate matter or chemicals

Survival may be possible in cold water submersion that lasts >1 hour, especially among children; thus, even patients with prolonged submersion are vigorously resuscitated.

Prevention of Drowning

Drugs, alcohol, and drowning

Use of alcohol or drugs is a major risk factor and should be avoided before and during swimming and boating, and when supervising children around water.

Swimming safety

Swimmers should use common sense and be aware of weather and water conditions. Swimmers should be accompanied by an experienced swimmer or swim only in guarded areas. Swimming should stop if the swimmer looks or feels very cold, because hypothermia may impair judgment. Ocean swimmers should learn to escape rip currents by swimming parallel to the beach rather than directly toward the beach. Swimmers should be discouraged from dangerous underwater breath-holding behaviors (DUBBs). If they practice them, they should be supervised and should know their dangers. Swimmers should avoid swimming near a boat exhaust port, which can cause carbon monoxide poisoning.

Public swimming areas should be supervised by lifeguards trained in water safety and resuscitation as well as rescue techniques. Life preservers, life jackets, and a shepherd's crook should be available close to poolside. Emergency airway equipment, automated external defibrillators (AEDs), and immediate telephone access to emergency medical services should be available. Comprehensive community prevention programs should target high-risk groups, teach children to swim as early as possible, and teach cardiopulmonary resuscitation (CPR) to as many adolescents and adults as possible. Owners of private pools should comply with local laws regarding pool safety, have immediate telephone access to emergency medical services, and know about resuscitation after drowning.

Water safety for children

Children should wear flotation devices that have been approved by the US Coast Guard or other equivalent authority when in or around water. Air-filled swimming aids and foam toys (water wings, noodles, etc) are not designed to keep swimmers from drowning and should not be used as a substitute for approved safety equipment.

Children must be constantly supervised by an adult when around water, including beaches, pools, and ponds. Infants and toddlers should also be supervised, ideally within arm’s length, when near toilets, bathtubs, or any collection of water.

Studies in the US and China have shown that formal swimming lessons reduce the risk of fatal drowning among children ages 1 to 4; however, even children who have been taught how to swim require constant supervision when in or around water.

Adults should remove water from containers such as pails and buckets immediately after use. Swimming pools should be surrounded with a locked fence 1.5 m in height.

Boating safety

Before embarking, boaters should wear life jackets approved by the US Coast Guard or other equivalent authority and they should check weather and water conditions. Nonswimmers and small children in a boat should wear appropriately approved life jackets at all times. Because consuming any quantity of alcohol increases the risk of drowning, operators and passengers on recreational boats should generally avoid consuming alcohol.

Special populations at risk for drowning

People who are debilitated or older or have seizure disorders or other medical conditions that can alter consciousness require constant supervision when they are boating or swimming and when in bathtubs.

People with a personal or family history of unexplained drowning not attributable to alcohol use, drug use, or a seizure disorder merit evaluation for arrhythmogenic cardiac disorders.

Key Points

  • Take preventive measures (eg, provide or take swimming lessons, closely supervise children around water, use flotation devices or life jackets that have been approved by the US Coast Guard or other equivalent authority, avoid alcohol, and ensure access to trained lifeguards and emergency medical services) to decrease the risk of drowning.

  • Begin resuscitation of patients in cardiac arrest from drowning with rescue breathing, not chest compressions.

  • Vigorously resuscitate cold water drowning victims even if submersion was prolonged; survival is possible even after 1 hour of submersion, particularly in young children.

  • Evaluate patients for suspected causes of drowning (eg, cervical spine injury, head injury, seizure, arrhythmias, hypoglycemia) as well as injuries or consequences of drowning (eg, head or cervical spine injury, aspiration).

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