Drowning causes half a million deaths per year, worldwide. In many countries, drowning is one of the most common causes of all deaths for children less than 12 years old. In the United States and Australia, it is the second leading cause of death, after motor vehicle accidents, in children less than 12 years old.
The worldwide death rate from drowning is 6.8 per 100 000 person years. The rate of drowning in different populations varies widely according to their access to water, the climate and the national swimming culture. The incidence in most developed countries has now dropped to less than 2 per 100 000. In Africa and in Central America, the incidence is 10 to 20 times higher than this. Island nations with dense populations, such as Japan and Indonesia, are more vulnerable than are large continental nations.
Key risk factors for drowning are male sex, age less than 14 years, alcohol use, low income, poor education, rural residency, aquatic exposure, risky behavior and lack of supervision. Epilepsy increases the risk of drowning by 15 times. The exposure-adjusted, person-time risk of drowning is 200 times higher than that from traffic accidents. For every person who dies of drowning, at least another 4 persons receive care in the emergency department for ‘non-fatal drowning’.
There is a predictable age distribution for specific types of drowning. Most swimming pool deaths occur in children, surf deaths occur mostly in teenagers and young adults, ocean deaths occur in sailors and fishers throughout the whole adult range and bathtub drowning occurs in either young babies or older infirm persons. Homicides occur in all ages.
Alcohol consumption is involved in more than half the adult male drowning cases. This may result from the following:
- Increased risk-taking activities.
- Reduced capacity to respond to a threatening situation.
- Loss of heat secondary to peripheral vasodilatation.
- Interference with the laryngeal reflex.
- Increased vagal response.
- Increased tendency to vomit.
- Suicidal intentions.
‘Bacchus hath drowned more men than Neptune’. Old English Adage.
The demographic features of general drowning accidents are not reflected in the drowning of divers (see Chapter 25). Although it should be the simplest and most informed topic in diving medicine, drowning is plagued with paradoxes. It is responsible for most diving fatalities, but unless other explanations are added, it is a totally inadequate explanation. Divers, unlike other aquatic adventurers, carry their own breathable gas supply (their life support system) with them, and unless this is interrupted in some way, drowning per se is inexplicable. It is a grossly oversimplified diagnosis without determining what has compromised this respirable gas supply or what complications have ensued.