eMedicine Specialties > Emergency Medicine > Environmental

Drowning

Suzanne Moore Shepherd, MD, MS, DTM&H, FACEP, FAAEM, Associate Professor, Department of Emergency Medicine, Hospital of the University of Pennsylvania; Director of Education and Research, PENN Travel Medicine
William H Shoff, MD, DTM&H, Director, PENN Travel Medicine, Associate Professor, Department of Emergency Medicine, Hospital of the University of Pennsylvania

Updated: Jun 9, 2009

Introduction

Background

Drowning is a significant cause of disability and death. Drowning has been previously defined as death secondary to asphyxia while immersed in a liquid, usually water, or within 24 hours of submersion. At the 2002 World Congress on Drowning, held in Amsterdam, a group of experts suggested a new consensus definition for drowning in order to decrease the confusion over the number of terms and definitions (>20) referring to this process that have appeared in the literature.¹ The group believed that a uniform definition would allow more accurate analysis and comparison of studies, allow researchers to draw more meaningful conclusions from pooled data, and improve the ease of surveillance and prevention activities.

The new definition states that drowning is a process resulting in primary respiratory impairment from submersion in a liquid medium. Implicit to this definition, is that a liquid-air interface is present at the victim's airway. Outcome may include delayed morbidity or death, death, or life without morbidity. The terms wet drowning, dry drowning, active or passive drowning, near-drowning, secondary drowning, and silent drowning would be discarded.

The classic image of a victim helplessly gasping and thrashing in the water rarely is reported. A more ominous scenario of a motionless individual floating in the water or quietly disappearing beneath the surface is more typical.

Pathophysiology

The principal physiologic consequences of drowning are prolonged hypoxemia and acidosis and the multiorgan effects of these processes.

After initial gasping and possible aspiration, immersion stimulates hyperventilation, followed by voluntary apnea and a variable degree and duration of laryngospasm (see Media file 1). This leads to hypoxemia.

Mechanism of hypoxia in submersion injury.

In young children suddenly immersed in cold water (<20°C), the mammalian diving reflex may occur and produce apnea, bradycardia, and vasoconstriction of nonessential vascular beds with shunting of blood to the coronary and cerebral circulation.

The target organ of submersion injury is the lung. Aspiration of 1-3 mL/kg fluid leads to significantly impaired gas exchange. Injury to other systems is largely secondary to hypoxia and ischemic acidosis. Additional CNS insult may result from concomitant head or spinal cord injury. Fluid aspirated into the lungs produces vagally mediated pulmonary vasoconstriction and hypertension. Fresh water moves rapidly across the alveolar-capillary membrane into the microcirculation. Surfactant is destroyed, producing alveolar instability, atelectasis, and decreased compliance with marked ventilation/perfusion (V/Q) mismatching. As much as 75% of blood flow may circulate through hypoventilated lungs.

In salt water drowning, surfactant washout occurs, and protein-rich fluid exudates rapidly into the alveoli and pulmonary interstitium. Compliance is reduced, alveolar-capillary basement membrane is damaged directly, and shunting occurs. This results in rapid induction of serious hypoxia. Fluid-induced bronchospasm also may contribute to hypoxia. The distinction between fluid type is somewhat academic, as other than epidemiologic importance, the initial treatment is similar.

Frequency

United States

More than 8,000 deaths are due to drowning annually in the United States, with 1,500 of these deaths occurring in children. In 2005, the Centers for Disease Control and Prevention reported that 3,582 unintentional fatal drownings occurred in the United States.⁶ This averages to 10 deaths per day. Approximately one quarter of these deaths occur in children 14 years or younger. Four times as many children receive emergency department care for nonfatal injuries for every child that dies. In fact, a bimodal distribution of deaths is observed, with an initial peak in the toddler age group and a second peak in adolescent to young adult males.

In the toddler group, most incidents occur in bathtubs and swimming pools. In the adolescent and young adult groups (aged 15-24 y), most incidents occur in natural bodies of water. For every death from drowning, an estimated 4 individuals are hospitalized and 14 individuals visit the ED.

In 2005, of all children aged 1-4 years who died, almost 30% died from drowning. Despite preventative measures, the 2006 NationalCenter for Injury Prevention and Control statistics noted drowning to be second only to motor vehicle collisions as the most common cause of death in children aged 1-14 years.⁷ Morbidity from submersion occurs in 12-27% of survivors in this age group. Preschool-aged boys are at greatest risk of submersion injury. A survey of 9420 primary school children in South Carolina estimated that approximately 10% of children younger than 5 years had an experience judged a "serious threat" of near drowning. Residential swimming pools are the most common submersion site in this age group.^8,9

An additional 1,200 reported immersion deaths are boating related (90% of boating deaths), 500 are motor vehicle associated, and 1,000 reported drownings are of undetermined etiology. Studies in a number of countries with active fishing industries have targeted drowning for injury control and prevention. 

Scuba diving accounts for an estimated 700-800 deaths per year (etiologies include inadequate experience/training, exhaustion, panic, carelessness, and barotrauma). Denoble et al studied 947 recreational diving accidents from 1992-2003, during which 70% of the victims drowned. Drowning was usually secondary to a disabling injury, equipment problems, problems with air supply, and cardiac events in these individuals.¹⁰

Submersion-related injuries are the fifth leading cause of accidental death in the United States in all age groups; incidence is approximately 2.5-3.5 per 100,000 population. California reports approximately 25,000 ocean rescues on its beaches each year. However, true incidence of near drowning has yet to be defined accurately, since many cases are not reported.

International

Annually, approximately 150,000 deaths are reported worldwide from drowning, with an annual incidence probably closer to 500,000. Several of the most densely populated nations in the world fail to report near-drowning incidents. This, along with the fact that many cases are never brought to medical attention, renders accurate worldwide incidence approximation virtually impossible.

The incidence of near drowning has an estimated range of 20-500 times the rate of drowning.

A Danish occupational medical study of 114 drowning fatalities in the period 1989-2005 among fishing industry seamen, found that approximately one half of the deaths occurred during vessel disasters in rough weather, with capsizing and foundering, or collisions. One third occurred during other occupational accidents that caused the victim to go overboard. One third occurred when the victim underwent difficult disembarkation during nighttime hours in foreign ports or was intoxicated.¹¹

A recent Canadian study of drowning during work-related and recreational helicopter crashes over water also focused on factors that increased the likelihood of death, especially in settings with limited warning time. The authors found that educational strategies to increase survival likelihood included wearing survival gear during the trip, prior escape training, ensuring that crew and passengers possessed appropriate knowledge of escape routes, and assuming appropriate crash positioning. They suggested that companies using helicopter transport over water should focus on regular and repeated safety training and improvement in safety measures on helicopters.¹²

Mortality/Morbidity

Morbidity and death in immersion injuries are due primarily to laryngospasm and pulmonary injury, resulting hypoxemia and acidosis, and their effects on the brain and other organ systems.

Prevention is as important as any measures that can be taken after the fact.

• A high risk of death exists secondary to the development of adult respiratory distress syndrome (ARDS), which has been termed postimmersion syndrome or secondary drowning. Morbidity is due to neurologic insult as well as to multiple organ system failure.
• The adult mortality rate is difficult to quantify because of poor reporting and inconsistent record keeping.
• Thirty-five percent of immersion episodes in children are fatal; 33% result in some degree of neurologic impairment and 11% in severe neurologic sequelae.

In 2002, per CDC data, approximately 2,822 individuals are treated for drowning in US Emergency Departments.

Race

The overall rate of drowning for African American children is 1.7 times higher than that for white children; however, the relative rates vary with age.

• African American children aged 0-4 years exhibit a lower rate of drowning (2.32 per 100,000), probably secondary to less pool access.
• In older pediatric age groups, the incidence is 2-5 times higher.

Sex

• Male-to-female ratios are approximately 12:1 for boat-related drownings and 4:1 for non–boat-related drownings.
• Only in bathtub incidents do girls predominate in incidence.

Age

Peak incidences of submersion injury occur in the following 2 age groups:

• Children younger than 4 years
• Young adults aged 15-24 years

Clinical

History

• Typical incidents involve a toddler left unattended temporarily or under the supervision of an older sibling, an adolescent found floating in the water, or a victim diving and not resurfacing. Less typically, submersion injury may be a deliberate form of child abuse, including Munchhausen syndrome by proxy.
• The age of the victim, submersion time, water temperature, water tonicity, degree of water contamination, symptoms, associated injuries (especially cervical spine and head), presence of co-ingestants, underlying medical conditions, type and timing of rescue and resuscitation efforts, and response to initial resuscitation are all relevant factors.
  • Thermal conduction of water is 25-30 times that of air. The temperature of thermally neutral water, in which a nude individual's heat production balances heat loss, is 33°C.
  • Physical exertion increases heat loss secondary to convection/conduction up to 35-50% faster.
  • A significant risk of hypothermia usually develops in water temperatures less than 25°C, which is the temperature found in most US natural waters during the majority of the year.
  • During immersion in ice water, a subject will become hypothermic in approximately 30 minutes. Cooling at this temperature becomes life-threatening in approximately 60 minutes.¹³
• Other important historical factors include the following:
  • Shortness of breath, difficulty breathing, apnea
  • Persistent cough, wheezing
  • In stream, lake, or salt water immersion, possible aspiration of foreign material, or exposure to fungi, bacteria, and other microorganisms
  • Level of consciousness at presentation, history of loss of consciousness, anxiety
  • Vomiting, diarrhea
  • Coincident alcohol or drug use
  • Pertinent past medical history, particularly seizure disorder, diabetes mellitus, psychiatric history, severe arthritis, or neuromuscular disorder - A United Kingdom study examined the risk of drowning in individuals with epilepsy and found the risk increased 15 to 19 fold.¹⁴
• Bradycardia or tachycardia, dysrhythmia

Physical

A victim of a submersion incident may be classified initially into 1 of the following 4 groups:

• Asymptomatic
• Symptomatic
  • Altered vital signs (eg, hypothermia, tachycardia, bradycardia)
  • Anxious appearance
  • Tachypnea, dyspnea, or hypoxia: If dyspnea occurs, no matter how slight, the patient is considered symptomatic.
  • Metabolic acidosis (may exist in asymptomatic patients as well)
  • Altered level of consciousness, neurologic deficit
• Cardiopulmonary arrest
  • Apnea
  • Asystole (55%), ventricular tachycardia/fibrillation (29%), bradycardia (16%)
  • Immersion syndrome
• Obviously dead
  • Normothermic with asystole
  • Apnea
  • Rigor mortis
  • Dependent lividity
  • No apparent CNS function

Causes

• Bathtub drowning is most common in children younger than 1 year.
  • Most of these victims drown during a brief (<5 min) lapse in adult supervision.
  • Bathtub and pail drownings may represent child abuse; carefully examine the child for other evidence of injury, review the child's history for previous events, and review the details of the incident very carefully with the child's parent or guardian.
• In preschool-aged children, drownings occur most commonly in residential swimming pools.
  • Many residential pools have no physical barrier between the pool and the home.
  • Open gates are involved in up to 70% of drownings in cases involving fenced-in pools. Pools may also be accessed through unlocked windows when the pool area abuts the house.
  • As recently pointed out in 2 studies from Australia (water tank drowning)¹⁵ and Bangladesh (ditches, canals, and ponds)¹⁶ , water exposure is both culturally and geographically related. Limiting access to these areas was again cited as an important target for prevention strategies.
• Young adults typically drown in ponds, lakes, rivers, and oceans. Approximately 90% of drownings occur within 10 yards of safety.
  • Cervical spine injuries and head trauma, which result from diving into water that may be shallow or contain rocks and other hazards, have been implicated.
  • Alcohol and, to a lesser extent, other recreational drugs are implicated in many cases. Australian, Scottish, and Canadian data showed that 30-50% of older adolescents and adults who drowned in boating incidents were inebriated, as determined by blood alcohol concentrations.
• Consider underlying disease/illness in all age groups.
  • Seizure disorder
  • Myocardial infarction (MI) or syncopal episode
  • Poor neuromuscular control, such as that seen with significant arthritis, Parkinson disease, or other neurologic disorders
  • Major depression/suicide - A recent study by the European Alliance Against Depression reviewed gender-specific suicide methods in 16 European countries.¹⁷ They found that women were more likely to choose drowning as a suicide method. They suggested that gender-specific prevention strategies should be developed.
  • Anxiety/panic disorder
  • Diabetes, hypoglycemia
• Water sports hazards, especially with personal watercraft
  • Poor judgment and substance abuse (alcohol or other recreational drugs) in conjunction with boat operation
  • Cervical spine injury and head trauma associated with surfing, water skiing, and jet skiing
  • Scuba diving accidents and other injuries (eg, bites, stings, lacerations)

Differential Diagnoses

Spinal Cord Injuries
Ventricular Fibrillation

Other Problems to Be Considered

Head trauma
Arrhythmia
Seizure

Workup

Laboratory Studies

• Arterial blood gas analysis
  • Arterial blood gas (ABG) analysis is probably the most reliable clinical parameter in patients who are asymptomatic or mildly symptomatic.
  • A surprising degree of hypoxia can exist without clinical signs.
• Obtain blood for a rapid glucose determination, CBC count, electrolyte levels, lactate level, and coagulation profile, if indicated. Collect urine for urinalysis, if indicated.
  • If initial test results show elevated serum creatinine level, marked metabolic acidosis, abnormal urinalysis, or significant lymphocytosis, serial estimations of serum creatinine should be performed.
  • Acute renal impairment is known to occur frequently in near drowning, and, while usually mild (serum creatinine level <0.3 mmol/L or 3.4 mg/dL), severe renal impairment requiring dialysis may occur.
• Consider a blood alcohol level and urine toxicology screen for use of drugs.

Imaging Studies

• Chest radiography
  • For evidence of aspiration, pulmonary edema, or segmental atelectasis suggesting foreign body(s) (eg, silt or sand aspiration)
  • For evaluation of endotracheal (ET) tube placement
• Cervical spine radiograph or computed tomography (CT) scanning in individuals with an appropriate history, neck pain, or if doubt exists about the circumstances surrounding the submersion injury
• Noncontrast head CT scanning in an individual with altered mental status and a suggestive or unclear history

Other Tests

• Continuous pulse oximetry
• Electrocardiography if evidence of significant tachycardia, bradycardia, or dysrhythmia or risk of underlying cardiac disease

Procedures

• Endotracheal intubation and mechanical ventilation may be indicated in awake individuals unable to maintain adequate oxygenation on oxygen by mask or via continuous positive airway pressure (CPAP) or in whom airway protection is warranted.
• Extracorporeal membrane oxygenation (ECMO) has been shown to be beneficial in individuals with respiratory compromise despite intubation and aggressive mechanical ventilation and persistent hypothermia unresponsive to other warming methods.
  • Bronchoscopy may be necessary for removal of significant inhaled sediment.
  • Aggressive warming, with method dependent on the degree of hypothermia and the patient's response, may be warranted.
  • Central venous pressure monitoring may be warranted.
  • Urinary catheterization for ongoing urine output measurement may be warranted.

Treatment

Prehospital Care

Bystanders should call 911 immediately. They should never assume the individual is unsalvageable unless it is patently obvious that the individual has been dead for quite a while. If they suspect injury, they should move the individual the least amount possible and begin cardiopulmonary resuscitation (CPR).

Prehospital care is focused on the following important points:

• Optimal prehospital care is a significant determinant of outcome in the management of immersion victims. The victim should be removed from the water at the earliest opportunity. Rescue breathing should be performed while the individual is still in water, but chest compressions are inadequate because of buoyancy issues. The patient should be removed from the water with attention to cervical spine precautions. If possible, the individual should be lifted out in a prone position. Theoretically, hypotension may follow lifting the individual out in an upright manner because of the relative change in pressure surrounding the body from water to air. Management of the ABCs is the priority, with particular attention to securing the earliest possible airway and providing adequate oxygenation and ventilation.
  • In the patient with an altered mental status, the airway should be checked for foreign material and vomitus.
  • Intrinsic compressions to remove water from the lungs is not recommended, as they have proven not to remove fluid, delay the start of resuscitation, risk causing the patient to vomit and aspirate, and ventilation is achieved even if fluid is present in the lung. If the rescuer is unable to ventilate the patient, then an airway clearing method should be attempted.
  • Immediately place the patient on 100% oxygen by mask. If available, continuous noninvasive pulse oximetry is optimal. If the patient remains dyspneic on 100% oxygen, or manifests a low oxygen saturation, use CPAP if available. If it is not available, consider early intubation, with appropriate use of positive end-expiratory pressure (PEEP).
• Immobilize the neck if the patient has facial or head injury, is unable to give an adequate history, or may have been involved in a diving accident or MVA.
• More traditional literature proposes that prehospital care providers should begin rewarming. Wet clothing is ideally removed before the victim is wrapped in warming blankets. More recent studies suggest that therapeutic cooling may actually be beneficial in patients to reduce ischemic brain injury. This area needs additional vigorous clinical research to determine the most efficacious treatment strategy.¹⁸

Emergency Department Care

Initial management of near drowning should place emphasis on immediate resuscitation and treatment of respiratory failure. Evaluate associated injuries early, as a cervical spine injury may complicate airway management. Provide all victims of a submersion injury with supplemental oxygen during their evaluations.

• ET intubation: Intubation may be required in order to provide adequate oxygenation in a patient unable to maintain a pO₂ of greater than 60-70 mm Hg (>80 mm Hg in children) on 100% oxygen by face mask.
  • In the alert, cooperative patient, use a trial of bilevel positive airway pressure (BiPAP)/CPAP, if available, to provide adequate oxygenation before intubation is performed.
  • Other criteria for ET intubation include the following:
    • Altered level of consciousness and inability to protect airway or handle secretions
    • High alveolar-arterial (A-a) gradient - PaO₂ of 60-80 mm Hg or less on 15 L oxygen nonrebreathing mask
    • Respiratory failure - PaCO₂ >45 mm Hg
    • Worsening ABG results
• Intubated victims of submersion injury may require PEEP with mechanical ventilation to maintain adequate oxygenation. PEEP has been shown to improve ventilation patterns in the noncompliant lung in several ways, including (1) shifting interstitial pulmonary water into the capillaries, (2) increasing lung volume via prevention of expiratory airway collapse, (3) providing better alveolar ventilation and decreasing capillary blood flow, and (4) increasing the diameter of both small and large airways to improve distribution of ventilation.
• ECMO has been shown to be helpful in individuals who remain hypoxic despite aggressive mechanical ventilation. 
• Bronchoscopy may be needed to remove foreign material, such as aspirated debris or vomitus plugs from the airway.
• Temperature management: Optimal temperature management in drowning patients is a current topic of significant research and clinical interest. Hypothermic patients with core temperatures less than 86°F, who have undergone sudden, rapid immersion, may display slowing of metabolism and preferential shunting of blood to the heart, brain, and lungs, which may exert a protective effect during submersion. This is not, however, the case with most immersion victims, who have become hypothermic gradually and are at risk for ventricular fibrillation and neurologic injury. As such, traditional studies would suggest vigorous rewarming of hypothermic patients to normothermia. In order to rewarm, a number of modalities may be used.
  • Many authors have postulated that a primitive mammalian diving reflex may be responsible for survival after extended immersion in cold water. The mechanism for this reflex has been postulated to be reflex inhibition of the respiratory center (apnea), bradycardia, and vasoconstriction of nonessential capillary beds triggered by the sensory stimulus of cold water touching the face; these responses preserve the circulation to the heart and brain and conserve oxygen, thereby prolonging survival. The sudden temperature drop may depress cellular metabolism significantly, limiting the harmful effects of hypoxia and metabolic acidosis.
  • Place a nasogastric tube to assist in rewarming efforts and urinary catheter to assess urine output.
  • Core rewarming with warmed oxygen, continuous bladder lavage with fluid at 40°C, and intravenous (IV) infusion of isotonic fluids at 40°C should be initiated during resuscitation.
  • Warm peritoneal lavage may be required for core rewarming in patients with severe hypothermia.
  • A cascade unit on the ventilator provides warm inspired air.
  • Thoracotomy with open heart massage and warm mediastinal lavage may be effective. The hypothermic heart is typically unresponsive to pharmacotherapy and countershock.
  • Extracorporeal blood rewarming may be used in patients with severe hypothermia who do not respond to lavage/thoracotomy or who are in arrest.
  • Attempt central venous access cautiously in these patients in order to avoid stimulation of the hypothermic atrium and resultant dysrhythmias.
  • Do not abandon resuscitation of a submersion victim until the patient has been warmed to a minimum of 30°C.
• Newer literature, however, suggests that therapeutic hypothermia may be effective in reducing ischemic brain injury. 
  • Therapeutic hypothermia (TH) improves oxygen supply to ischemic brain areas, decreases cerebral metabolic demand, and decreases increased intracranial pressure. In 2002, the American Heart Association, followed in 2003 by the European Resuscitation Council, based on the results of blinded, randomized, multicenter clinical trials, recommended therapeutic hypothermia as a treatment modality for out-of-hospital comatose victims of cardiac arrest. Two cases in drowning victims in patients with full neurologic recovery after coma and cardiac arrest suggest that therapeutic hypothermia may confer neuroprotection.¹⁸ This area needs additional vigorous clinical research to determine the most efficacious treatment strategy. 
  • In the interim, it would appear appropriate for individual jurisdiction EMS directors to meet with their local referral hospital(s) to determine current temperature management strategy.
• Initiate appropriate treatment of hypoglycemia and other electrolyte imbalances; seizures; bronchospasm; and cold-induced bronchorrhea, dysrhythmias, and hypotension as necessary.
• Patient disposition depends on the history, presence of associated injuries, and degree of immersion injury.
  • Patients able to relay a good history of minor immersion injury, without evidence of significant injury and without evidence of bronchospasm, tachypnea/dyspnea, or inadequate oxygenation (by ABG analysis and pulse oximetry) can be safely discharged from the ED after 6-8 hours of observation. However, be aware that these studies did not include older individuals or in those with underlying medical conditions that might place them at increased risk of hypoxic injury and acidosis.
  • Victims of mild to moderately severe submersion, who only have mild symptoms that improve during observation and have no abnormalities on ABG analysis or pulse oximetry and chest radiograph, should be observed for a more prolonged period of time in the ED or observation unit.
  • Certain patients may display mild to moderately severe hypoxemia that is corrected easily with oxygen. Admit these patients to the hospital for observation. They can be discharged after resolution of hypoxemia if they have no further complications.
  • Admit patients who require intubation and mechanical ventilation to the ICU. Varying degrees of neurologic as well as pulmonary insults typically complicate their courses.

Consultations

• Neurosurgical, orthopedic, or trauma consultation (institution dependent) is required for patients with concomitant significant head or neck trauma.
• Early consultation with the intensivist or admitting physician is wise for patients who exhibit pulmonary or CNS insult in order to coordinate ongoing ICU care.
• Cardiovascular, intensivist, or trauma surgical consultation may be necessary for patients who require bypass for rewarming or ECMO.

Medication

Cold-induced bronchorrhea or irritation of the tracheobronchial tree by inhaled water or particulate material can produce cough and bronchospasm. Manage these aggressively because they may worsen hypoxia. The DOC is an inhaled beta-agonist bronchodilator.

Sympathomimetic agents

These agents relax bronchial smooth muscle during bronchospasms.

Albuterol (Proventil, Ventolin)

Relaxes bronchial smooth muscle by action on beta 2-receptors and has little effect on cardiac muscle contractility.

Dosing

Adult

Nebulizer: 1.25-2.5 mg diluted in 2-5 mL sterile saline or water

Pediatric

Nebulizer
<5 years: 1.25-2.5 mg q4-6h prn
>5 years: Administer as in adults

Interactions

Beta-adrenergic blockers antagonize effects; inhaled ipratropium may increase duration of bronchodilatation; cardiovascular effects may increase with MAOIs, inhaled anesthetics, tricyclic antidepressants, and other sympathomimetic agents

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in hyperthyroidism, diabetes mellitus, and cardiovascular disorders

Follow-up

Further Inpatient Care

• The primary management goals are good pulmonary care and preservation of CNS perfusion and function.
• Certain patients may display mild to moderately severe hypoxemia that is corrected easily with oxygen. Admit these patients to the hospital for observation. They can be discharged after resolution of hypoxemia if they have no further complications.
• Admit patients who require intubation and mechanical ventilation to the ICU. Varying degrees of neurologic as well as pulmonary insults typically complicate their course. Pulmonary hypertension may result from the release of inflammatory mediators, increasing right ventricular afterload, and decreasing left ventricular preload and pulmonary perfusion. Newer ventilatory modes, including airway pressure release ventilation and high frequency oscillatory ventilation can decrease the risk of VALI.
• In patients with significant lung disease but a reasonable likelihood of neurologic recovery, ECMO has been used successfully to treat pulmonary insufficiency.
• Myocardial dysfunction may result from PEA, dysrhythmias due to hypoxemia, acidosis, electrolyte disturbances, or hypothermia. These are usually transient in nature.  
• Look for evidence of ARDS; multiple organ system failure; nosocomial infection, especially pneumonia; and/or gastric stress ulceration.
  • Management of ARDS due to submersion is similar to that of ARDS from other causes.
  • Use of permissive hypercapnia to decrease barotrauma in many patients with ARDS may not be appropriate in this setting of hypoxic ischemic CNS injury.
• The extent of invasive monitoring needed (eg, arterial catheter, pulmonary artery catheter, central venous pressure catheter) is determined by the degree of hemodynamic or respiratory instability and the presence of renal failure.
• Invasive monitoring of intracranial pressure has been shown in both human and animal studies to be neither useful nor necessary.
• Watch for evidence of pneumonia and CNS infection. Uncommon infections may present late and unusually. Prophylactic antimicrobial therapy has not proven beneficial.
• Begin early and aggressive rehabilitation to prevent disuse injury. 

Further Outpatient Care

• Outpatient care is dictated by the nature and degree of residual functional impairment. With severe neurologic impairment, the patient may benefit from admission to a rehabilitation facility and aggressive rehabilitation. In one case report, neuropsychological testing delineated problems with memory, visuospatial performance, executive function, verbal fluency, flexibility, planning, and abstraction. Visuospatial testing, verbal learning, recall, and logical reasoning showed improvement during their 3-year follow-up period.¹⁹
• Patients able to relay a good history of minor immersion injury, without evidence of significant injury and without evidence of bronchospasm, tachypnea/dyspnea, or inadequate oxygenation (by ABG analysis and pulse oximetry) can be discharged from the ED after 6-8 hours of observation.
• Be aware that early ED discharge has not been studied in older individuals or in those with underlying medical conditions that might place them at increased risk of hypoxic injury. As such, these factors should be taken into consideration during discharge planning.
• Victims of mild to moderately severe submersion, who have only mild symptoms that improve during observation and have no abnormalities on ABG analysis or chest radiograph, can be discharged after a longer period of observation in the ED or observation unit.
• Tell discharged patients to return immediately if they develop dyspnea, cough, and/or fever.

Transfer

• Patients who exhibit significant hypoxia that requires intubation, worsening dyspnea with the potential for intubation, evidence of hypoxic cerebral injury, evidence of renal insufficiency, evidence of hemolysis, or severe hypothermia requiring cardiopulmonary bypass must be in a facility capable of providing appropriate, age-related intensive care.
• Manage patients who require care for significant cervical spine or head trauma in a facility capable of sophisticated neurologic monitoring and neurosurgical intervention.

Deterrence/Prevention

• Children, especially toddlers, should be supervised at all times when they are around water, including a bathtub or bucket full of water. Household buckets should be immediately emptied after use and left empty when not in use. Water containing objects, such as water tanks and cisterns, should have childproof fastenings and solid tops. They should not have items adjacent that afford children easy access.
• All pools should be fenced appropriately, with the gate to the area locked when not in use under adult supervision. These fences should be at least 4-5 ft tall. Pools not in use may be made safer with appropriately fitted and maintained pool covers and alarms, but these have not been shown to prevent drowning. Any windows with access to the pool area should remain closed and locked. Parents who own pools or who take their children to pools are encouraged to learn CPR. Children should wear personal flotation devices in pool areas, but these do not obviate the need for constant supervision. Children should be taught to swim, but these lessons should not provide parents with a false sense of security.
• All individuals involved in boating activities should be able to swim, should use personal flotation devices when on the boat or in the water, and should avoid the use of alcohol or other recreational drugs. Boaters should be taught to anticipate wind, waves, and water temperature, and to use protective suits and other insulating garments in cold weather.
• All children should be taught to check the water carefully for depth and possible injurious objects before diving in. Children should also be taught their swimming limitations and to not play dangerously in natural water areas, pools, or on the decks surrounding pools.
• All individuals should be taught not to drink alcohol or use other recreational drugs when swimming.
• Individuals with underlying medical illnesses that may place them at risk when swimming, such as seizure disorders, diabetes mellitus, significant coronary artery disease, severe arthritis, and disorders of neuromuscular function, should swim under the observation of another adult who can rescue them should they get into trouble.
• Individuals should not swim alone.
• For further information, see Injury Prevention.

Complications

• Neurologic injury
• Pulmonary edema and ARDS
• Secondary pulmonary infection
• Multiple organ system failure
• Acute tubular necrosis (secondary to hypoxemia)
• Myoglobinuria
• Hemoglobinuria

Prognosis

• Patients who are alert or mildly obtunded at presentation have an excellent chance for full recovery.
• Patients who are comatose, those receiving CPR at presentation to the ED, or those who have fixed and dilated pupils and no spontaneous respirations have a poor prognosis. In a number of studies, 35-60% of individuals needing continued CPR on arrival to the ED die, and 60-100% of survivors in this group experience long-term neurologic sequelae. Pediatric studies indicate that children who require specialized treatment for drowning in the pediatric intensive care unit (PICU) experience at least a 30% mortality rate and an additional 10-30% experience severe brain damage.

Patient Education

• Prevention is key. Community education is the key to prevention.
• Adults should know their own, and their children's, swimming limits.
• Parents should be warned not to swim unsupervised and always to supervise children carefully around water.
• Children should be taught safe conduct around water and during boating and jet- or water-skiing.
• Use of alcohol or other recreational drugs is not appropriate when swimming or engaging in other water sports.
• Appropriate boating equipment should be used, including personal flotation devices, and all boaters must understand weather and water conditions.
• Appropriate barriers must be used around pools, wading pools, and other water-containing devices at home. The US Consumer Product Safety Commission has published model regulations regarding pool fencing. Homeowners may consider installing a telephone poolside and teaching their children how to call 911.
• Parents should seriously consider learning CPR and water safety training in case rescue and resuscitation are needed. A 1990 study found that 86% of pool owners supported voluntary CPR training, while 40% of those surveyed supported mandatory training.²⁰
• For excellent patient education resources, visit eMedicine's Public Health Center and Environmental Exposures and Injuries Center. Also, see eMedicine's patient education articles Cardiopulmonary Resuscitation (CPR) and Drowning.

Miscellaneous

Medicolegal Pitfalls

• Management of hypoxemia is the key to the management of immersion injury. A surprising degree of hypoxia may be present in a relatively asymptomatic individual. Obtain pulse oximetry and ABG levels on all individuals with any history of submersion injury. Early use of intubation and PEEP, or CPAP/BiPAP in the awake, cooperative, and less hypoxic individual, is warranted in any patient who remains hypoxic or dyspneic on 100% oxygen.
• Remember that cervical spine trauma may be present in any victim of shallow- or rocky-water immersion injury. If the victim is unable to give a clear history of the events, has evidence of head or facial injury, or is found unresponsive in a pool or other shallow body of water, protect the cervical spine until injury is excluded.
• Remember that most US waters usually are below thermal neutrality, and early temperature recording with appropriate temperature management.
• Consider child abuse in young children who are the victims of submersion injury in bathtubs, buckets, or other shallow water receptacles.

Multimedia

Media file 1: Mechanism of hypoxia in submersion injury.

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Keywords

drowning, near drowning, submersion injury, submersion injuries, immersion injury, immersion injuries, submersion-related injuries, asphyxia, hypoxemia, ischemic acidosis, aspiration of water, hypoxia, injuries in children, suicide, water safety, alcohol use, drug use, depression, boating accidents, scuba diving accidents

Contributor Information and Disclosures

Author

Suzanne Moore Shepherd, MD, MS, DTM&H, FACEP, FAAEM, Associate Professor, Department of Emergency Medicine, Hospital of the University of Pennsylvania; Director of Education and Research, PENN Travel Medicine
Suzanne Moore Shepherd, MD, MS, DTM&H, FACEP, FAAEM is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American Society of Tropical Medicine and Hygiene, International Society of Travel Medicine, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

Coauthor(s)

William H Shoff, MD, DTM&H, Director, PENN Travel Medicine, Associate Professor, Department of Emergency Medicine, Hospital of the University of Pennsylvania
William H Shoff, MD, DTM&H is a member of the following medical societies: American College of Physicians, American Society of Tropical Medicine and Hygiene, International Society of Travel Medicine, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Glaxo Smith Kline Consulting fee Consulting; Glaxo Smith Kline Honoraria Speaking and teaching

Medical Editor

Robert L Norris, MD, Associate Professor, Department of Surgery; Chief, Division of Emergency Medicine, Stanford University Medical Center
Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, California Medical Association, International Society of Toxinology, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

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Eddy Lang, MDCM, CCFP (EM), CSPQ, Assistant Professor, Department of Family Medicine, McGill University; Consulting Staff, Department of Emergency Medicine, The Sir Mortimer B Davis-Jewish General Hospital
Eddy Lang, MDCM, CCFP (EM), CSPQ is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

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Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
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The authors and editors of eMedicine gratefully acknowledge the contributions of previous editor, Charles V Pollack Jr, MD, and previous author, James Martin, MD, to the development and writing of this article.

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