INTRODUCTION AND EPIDEMIOLOGY
Drowning is submersion in a liquid medium resulting in respiratory difficulty or arrest.1 As with other causes of accidental death, drowning injury typically involves otherwise healthy, young individuals, but can involve individuals of any age or background.
Worldwide, drowning accounts for >370,000 deaths annually and is the leading cause of injury death among children <15 years of age.1 In the United States, there are >500,000 drowning events each year and 1100 deaths, which makes drowning the second leading cause of unintentional death of individuals from birth to age 19 years old.2,3 Although the rate of drowning deaths has decreased over the past 40 years, it remains high in low- and middle-income countries, which account for 91% of unintentional drowning deaths worldwide annually.4 The vast majority of victims survive submersion events, with effects ranging from minimal or transient injury to profound neurologic insult.
Drowning incidence peaks in three age groups: The highest is in children <5 years old,2,3 the second peak is in those aged 15 to 24 years,2,3 and the third peak is in the elderly.5 Toddlers drown primarily after falling into swimming pools or open water, but they also drown in bathtubs and buckets in the home. Physicians also need to evaluate for intentional drowning (child abuse) or factitious disorder by proxy (formerly Munchausen’s by proxy). In teenagers and adults, suicide, homicide, and domestic violence can be causes of drowning. In this age group, drowning is also more likely if alcohol or drugs are involved.6 The elderly also have an increased risk of bathtub drowning, often related to comorbid medical conditions or medications. Even in coastal areas, most drownings take place in warm, freshwater bodies of water, especially swimming pools.
Additional injuries or disorders that either precipitate or are associated with drowning events are shown in Table 215-1.
TABLE 215-1Disorders and Injuries Associated With Drowning |Favorite Table|Download (.pdf) TABLE 215-1 Disorders and Injuries Associated With Drowning
Disorders Associated With Drowning
Alcohol or other intoxicants
Syncope (e.g., due to hyperventilation prior to underwater diving)
Cardiac conditions (e.g., dysrhythmias including prolonged QT syndromes, Brugada’s syndrome, ischemic heart disease)
Intentional (suicide, homicide, child abuse or neglect in young children)
Injuries Associated With Drowning
Spinal cord injuries due to diving into shallow water, significant falls from heights, or boating/personal watercraft mishaps
Respiratory failure, insufficiency, or distress
After submersion, the degree of hypoxic insult to the CNS determines the ultimate outcome. It was previously thought that parasympathetic activation of the diving reflex (i.e., bradycardia, apnea, peripheral vasoconstriction, and central shunting of blood flow) provided transient protection during submersion. However, in most cases, the diving reflex is overwhelmed by the stimulation of the sympathetic nervous system, yielding no meaningful protection.5 Cerebral protection in ...