DESCRIPTION

• The World Congress on Drowning defines it as “the process of experiencing respiratory impairment from submersion/immersion in liquid.”
• Regardless if the victim lives or dies, the person is still considered to have been involved in a drowning incident.
  • Any death related to drowning is termed as fatal drowning.
  • A nonfatal drowning occurs if the incident does not result in death.
  • If there is submersion or immersion without respiratory impairment, it is not a drowning incident and rather a water rescue.

• The terms near drowning, dry drowning, delayed drowning, and secondary drowning are not medically accepted diagnoses.

EPIDEMIOLOGY

• The World Health Organization (WHO) estimates that 236,000 fatal drownings occurred in 2019.
• Globally, drowning is the leading cause of death among boys aged 5 to 14 years.
• In the United States, it is the second leading cause of death related to injury in children aged 1 to 14 years.
• Location of drowning varies by age:
  • For infants, most drownings occur at home (78%).
  • In children 1 to 4 years of age, the majority of drownings occur in pools (55%).
  • Among children and adolescents aged 10 to 19 years, freshwater is the predominant site.
• Most incidents occur on weekends, June through August having the highest rates.

RISK FACTORS

• Children aged <4 years, males, those with low-income status are at greatest risk.
• Unsupervised access to swimming pools, spas, or natural bodies of water
• Among adolescents: overestimation of skills, high-risk/impulsive behavior, alcohol and illicit substance use
• Underlying medical/behavioral conditions:
  • Children with epilepsy have >4 times the risk of those without epilepsy.
  • Primary cardiac dysrhythmias, such as congenital long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia
  • Hypertrophic obstructive cardiomyopathy
  • Autistic children, especially those who are younger and have significant intellectual ability

GENERAL PREVENTION

• It is estimated that approximately 80% of drownings are preventable.
• The most evidence-based interventions have been:
  • Four-sided pool fencing (at least 4 feet tall) with self-closing and self-latching gates prevents >50% of swimming pool drownings in younger children.
  • Life jackets for children of all ages when near water and when swimming
  • Swimming lessons for children aged ≥4 years
  • Adult supervision
  • Lifeguard supervision and cardiopulmonary resuscitation (CPR) training

PATHOPHYSIOLOGY

• The process begins when the airway goes below the surface of the liquid which is usually water (submersion) or when water splashes over the face (immersion).
• Any water that then enters the oropharynx is usually swallowed or spit out.
• Subsequently, there is a voluntary breath holding that typically lasts <1 minute.
• Aspiration of small amounts of water then triggers a coughing reflex and laryngospasm.
• At this point, the victim becomes hypoxic as they are unable to breathe.
• Intrapulmonary shunting through poorly ventilated areas ensues, inducing bronchospasm, surfactant washout and inactivation, impaired gas exchange from the aspirated fluid in the alveolar space, and atelectasis that all contribute to eventual acute respiratory distress syndrome (ARDS)
• Cerebral hypoxemia rapidly leads to apnea and loss of consciousness.
• Once this asphyxia occurs, cardiac deterioration ensues.
• The entire process from submersion/immersion to cardiac arrest usually occurs within minutes but can last up to an hour in unusual situations such as hypothermia.
• Cold water (<5°C) drowning has better prognosis as cooler temperatures are protective of the CNS, despite submersion times >5 minutes.

COMMONLY ASSOCIATED CONDITIONS

• Hypothermia should be presumed in all drowning victims.
• Predisposing medical conditions (hypoglycemia, seizures, intoxication, cardiac arrhythmias, etc.) should be considered.
• Cervical spine injuries are rare but should be considered in diving incidents or if there is a concomitant trauma.
• Nonaccidental trauma should be considered in bathtub submersion victims, especially when accompanied by inconsistent histories from caregivers, prior history of abuse, late presentation to care, or any other physical signs of abuse.