Description

Respiratory impairment resulting from submersion or immersion in liquid; a drowning event in which the process of respiratory impairment is stopped before death and the victim survives

Epidemiology

Incidence

• From 2011 to 2020, an average of 4,012 fatal unintentional drownings and an average of 8,061 emergency room (ER) visits due to nonfatal drowning occurred each year in the United States (1)
• Three age-related peaks: toddlers and young children (1 to 5 years old), adolescents and young adults (15 to 25 years old), and the elderly
• Nearly 80% of people who die from drowning are male (1).
• In swimming pools, black children aged 10 to 14 years drown at rates 7.6 times higher than white children, whereas in natural water, American Indian or Alaska Native children drown at rates 2.7 times higher than white children (1).

Prevalence

• Most common injury-related cause of death for children aged 1 to 4 years in the United States (2)
• Second most common injury-related cause of death for children aged 5 to 14 years in the United States after motor vehicle crashes (1)
• For every child aged <18 years who dies from drowning, seven more children are seen in the ER for nonfatal submersion injuries (1).

Etiology and Pathophysiology

Hypoxemia via aspiration and/or reflex laryngospasm causing cerebral hypoxia and multisystem organ dysfunction

• 10–20% of victims drown without aspiration, likely due to prolonged laryngospasm; bathtub and bucket drowning in children aged <1 year; swimming pool drowning in children and young adults; motor vehicle accidents (vehicle submerged in water); head trauma while swimming or diving
• Pulmonary: morbidity primarily caused by hypoxia; aspiration of 1 to 3 mL/kg of liquid causes dilution of surfactant with decreased gas transfer across alveoli, atelectasis, development of intrapulmonary right-to-left shunting; acute respiratory distress syndrome (ARDS); obstruction due to laryngospasm and bronchospasm (2)
• Cardiac: hypoxic-ischemic injury and arrhythmia (primary or secondary); renal: acute tubular necrosis from hypoxemia, shock, hemoglobinuria, myoglobinuria
• Neurologic: hypoxic-ischemic brain injury with damage especially to the hippocampus, insular cortex, and basal ganglia; cerebral edema and increased intracranial pressure
• Coagulation: hemolysis and coagulopathy

Risk Factors

• Inadequate physical barriers surrounding pools, alcohol ingestion, male sex, low socioeconomic status
• Use of illicit drugs, seizure disorder, inability to swim or overestimation of swimming capabilities, hyperventilation prior to underwater swimming
• Boating mishaps and trauma during water sports, particularly when not wearing a life jacket; scuba diving
• Inadequate adult supervision of children, lack of appropriate instruction on how to swim, concomitant stroke or myocardial infarction (MI), hypothermia
• Cardiac arrhythmias: familial long QT and polymorphic ventricular tachycardia (VT)

General Prevention

• Periodic education regarding proper supervision and drowning prevention for caretakers of young children; proper adult supervision of children, particularly around water; pool alarms, buddy system; knowledge of water safety guidelines
• Mandatory physical barriers surrounding pools; four-sided fencing; self-closing gate at least 48 inches above the ground (1)
• Avoid alcohol or recreational drugs around water; swimming instruction at an early age; cardiopulmonary resuscitation (CPR) instruction for pool owners and parents; boating safety knowledge; personal flotation device and rescue equipment (e.g., preserver, if necessary)

Pediatric Considerations
Children should never be left alone near water. Young children can drown in very small amounts of water (bathtubs, buckets of water, and toilets).

Commonly Associated Conditions

• Trauma, seizure disorder, alcohol or illicit drug use
• Hypothermia, concomitant stroke or MI, cardiac arrhythmias: familial long QT and familial polymorphic VT, hyperventilation
• Pneumonia, hypotension