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Drowning

(Fatal Drowning; Nonfatal Drowning)

By

David Richards

, MD, University of Colorado School of Medicine

Reviewed/Revised Jan 2023
View PATIENT EDUCATION
Topic Resources

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 General references 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... read more ). Groups at high risk of drowning death include the following:

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 General references 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... read more ).

Pathophysiology of Drowning

Hypoxia

Hypoxia Oxygen Desaturation Patients without respiratory disorders who are in the intensive care unit (ICU)—and other patients—may develop hypoxia (oxygen saturation < 90%) during a hospital stay. Hypoxia in patients... read more Oxygen Desaturation is the major insult in drowning, affecting the brain, heart, and other tissues; respiratory arrest Overview of Respiratory Arrest Respiratory arrest and cardiac arrest are distinct, but inevitably if untreated, one leads to the other. (See also Respiratory Failure, Dyspnea, and Hypoxia.) Interruption of pulmonary gas exchange... read more followed by cardiac arrest Cardiac Arrest Cardiac arrest is the cessation of cardiac mechanical activity resulting in the absence of circulating blood flow. Cardiac arrest stops blood from flowing to vital organs, depriving them of... read more may occur. Brain hypoxia may cause cerebral edema and, occasionally, permanent neurologic sequelae. Generalized tissue hypoxia may cause metabolic acidosis Metabolic Acidosis Metabolic acidosis is primary reduction in bicarbonate (HCO3), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly... read more . 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 Aspiration Pneumonitis and Pneumonia Aspiration pneumonitis and pneumonia are caused by inhaling toxic and/or irritant substances, most commonly large volumes of upper airway secretions or gastric contents, into the lungs. Chemical... read more or secondary bacterial pneumonia Overview of Pneumonia Pneumonia is acute inflammation of the lungs caused by infection. Initial diagnosis is usually based on chest x-ray and clinical findings. Causes, symptoms, treatment, preventive measures, and... read more and may impair alveolar secretion of surfactant, resulting in patchy atelectasis Atelectasis Atelectasis is collapse of lung tissue with loss of volume. Patients may have dyspnea or respiratory failure if atelectasis is extensive. They may also develop pneumonia. Atelectasis is usually... read more Atelectasis . Extensive atelectasis may make the affected areas of the lungs stiff, noncompliant, and poorly ventilated, potentially causing respiratory failure Overview of Respiratory Failure Acute respiratory failure is a life-threatening impairment of oxygenation, carbon dioxide elimination, or both. Respiratory failure may occur because of impaired gas exchange, decreased ventilation... read more with hypercapnia and respiratory acidosis Respiratory Acidosis Respiratory acidosis is primary increase in carbon dioxide partial pressure (Pco2) with or without compensatory increase in bicarbonate (HCO3); pH is usually low but may be near... read more . Perfusion of poorly ventilated areas of the lungs (V/Q mismatch) worsens hypoxia. Alveolar hypoxia may cause noncardiogenic pulmonary edema.

Hypothermia

Exposure to cold water induces systemic hypothermia Hypothermia Hypothermia is a core body temperature < 35° C. Symptoms progress from shivering and lethargy to confusion, coma, and death. Mild hypothermia requires a warm environment and insulating blankets... read more , 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 Aspiration Pneumonitis and Pneumonia Aspiration pneumonitis and pneumonia are caused by inhaling toxic and/or irritant substances, most commonly large volumes of upper airway secretions or gastric contents, into the lungs. Chemical... read more , sometimes with anaerobic or fungal pathogens, and pulmonary edema Immersion Pulmonary Edema Immersion pulmonary edema is sudden-onset pulmonary edema that typically occurs at the surface or early during a dive while at depth. (See also Overview of Diving Injuries.) Immersion pulmonary... read more .

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 Spinal Trauma Trauma to the spine may cause injuries involving the spinal cord, vertebrae, or both. Occasionally, the spinal nerves are affected. The anatomy of the spinal column is reviewed elsewhere. Spinal... read more Spinal Trauma (which may be the cause of drowning).

General references

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 Resuscitation after drowning 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... read more , 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 Pulse Oximetry Gas exchange is measured through several means, including Diffusing capacity for carbon monoxide Pulse oximetry Arterial blood gas sampling The diffusing capacity for carbon monoxide (DLCO)... read more 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 Diagnosis Trauma to the spine may cause injuries involving the spinal cord, vertebrae, or both. Occasionally, the spinal nerves are affected. The anatomy of the spinal column is reviewed elsewhere. Spinal... read more Diagnosis .

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 Long QT Interval Syndromes The long QT interval syndromes (LQTS) result from any congenital or acquired disorder of cardiac ion channel function or regulation (channelopathy) that prolongs ventricular myocyte action potential... read more , torsades de pointes ventricular tachycardia Torsades de Pointes Ventricular Tachycardia Torsades de pointes ventricular tachycardia is a specific form of polymorphic ventricular tachycardia in patients with a long QT interval. It is characterized by rapid, irregular QRS complexes... read more , and any other suspected arrhythmogenic cardiac disorders Overview of Arrhythmogenic Cardiomyopathies Although any dilated or hypertrophic cardiomyopathy (see Overview of Cardiomyopathies) can produce cardiac and systemic factors that predispose to a number of different arrhythmias, including... read more . 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.

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 Cardiopulmonary Resuscitation (CPR) in Adults Cardiopulmonary resuscitation (CPR) is an organized, sequential response to cardiac arrest, including Recognition of absent breathing and circulation Basic life support with chest compressions... read more . 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 Treatment references 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... read more ). Attempts to remove water from the lungs are avoided because they delay ventilation and increase the risk of vomiting. Oxygenation, endotracheal intubation Tracheal Intubation Most patients requiring an artificial airway can be managed with tracheal intubation, which can be Orotracheal (tube inserted through the mouth) Nasotracheal (tube inserted through the nose)... read more , or both should proceed as soon as possible. Hypothermic patients are warmed as soon as possible. Immediate treatment measures Treatment Hypothermia is a core body temperature < 35° C. Symptoms progress from shivering and lethargy to confusion, coma, and death. Mild hypothermia requires a warm environment and insulating blankets... read more 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 Overview of Mechanical Ventilation Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more 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 Noninvasive positive pressure ventilation (NIPPV) Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more 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 Treatment Hypothermia is a core body temperature < 35° C. Symptoms progress from shivering and lethargy to confusion, coma, and death. Mild hypothermia requires a warm environment and insulating blankets... read more 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 Overview of Spinal Cord Disorders Spinal cord disorders can cause permanent severe neurologic disability. For some patients, such disability can be avoided or minimized if evaluation and treatment are rapid. The spinal cord... read more , seizure Seizure Disorders A seizure is an abnormal, unregulated electrical discharge that occurs within the brain’s cortical gray matter and transiently interrupts normal brain function. A seizure typically causes altered... read more , arrhythmia Overview of Arrhythmias The normal heart beats in a regular, coordinated way because electrical impulses generated and spread by myocytes with unique electrical properties trigger a sequence of organized myocardial... read more Overview of Arrhythmias ) 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 Aspiration Pneumonitis and Pneumonia Aspiration pneumonitis and pneumonia are caused by inhaling toxic and/or irritant substances, most commonly large volumes of upper airway secretions or gastric contents, into the lungs. Chemical... read more , 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 Treatment references 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... read more , 3 Key Points 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... read more ). If symptoms resolve and the examination and oxygenation remain normal, patients can be discharged with instructions to return if symptoms recur.

Treatment references

  • 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. 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. 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 Hypothermia Hypothermia is a core body temperature < 35° C. Symptoms progress from shivering and lethargy to confusion, coma, and death. Mild hypothermia requires a warm environment and insulating blankets... read more 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.

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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