Near-drownings lead to permanent disabilities
Approximately 10 children drown every day in the United States. Four times that number receive emergency care for a nonfatal near-drowning episode that leaves many with permanent disabilities, including serious neurological problems. Most are younger than 14 years old, although boys ages 15 to 19 are also at high risk.
On family farms, most drownings and near-drownings occur in ponds and lagoons, and many involve unsupervised toddlers who get too close to the water's edge, lose their balance and fall in. Often, these children drown in very shallow water. Farm fatality data show that toddlers can also drown in wells, watering troughs and silage seepage puddles. Incidents involving older kids usually occur when ponds are used for recreational swimming or, in winter, for skating, sledding and fishing.
Although lack of adult supervision and alcohol and drug use contribute to some of these fatalities, others remain unexplained and may be secondary to health problems or abuse, according to Grace M. Arteaga, M.D., a specialist in Pediatric and Adolescent Medicine at Mayo Clinic's campus in Rochester, Minnesota.
"Children depend on high amounts of glucose for proper brain function. When they become hypoglycemic, it predisposes them to seizures and near-drowning incidents," she says. "We're also becoming more aware that children who have long QT syndrome (LQTS) or catecholaminergic polymorphic ventricular tachycardia (CPVT) can lose consciousness and drown," she says. "Both disorders can cause syncope and sudden cardiac death, usually after a trigger such as extreme emotion or exertion, especially swimming, so there should always be a suspicion of this in unexplained drownings."
A 2011 study published in Mayo Clinic Proceedings found that cardiac channel mutations played a role in 30 percent of swimming-related drownings. Other studies suggest as many as 50 percent of childhood drownings may be caused by LQTS or CPVT. The Mayo Clinic study did not find this connection in bathtub submersions but suggested some may be caused by epilepsy. Dr. Arteaga says abuse is also a possibility in bathtub and toilet drownings, especially those involving infants and toddlers.
Managing near-drowning patients
How near-drowning patients are managed depends on severity of symptoms and sometimes, but not always, submersion duration. Head and neck trauma should always be considered during resuscitation efforts, Dr. Arteaga says.
Patients free of symptoms are usually released at the scene. Those with rales and a small amount of foam should receive oxygen via a nasal cannula and undergo observation in the emergency department for six to 24 hours. But patients with acute pulmonary edema, respiratory arrest or cardiopulmonary arrest require advanced cardiac life support interventions and rapid transport to definitive care. Mortality rates for pulmonary edema, respiratory arrest and cardiopulmonary arrest in cases of near-drowning are 19 percent, 44 percent and 93 percent, respectively.
The extent of injury to the brain and nervous system usually determines outcomes in drowning cases. "A child who suffered very mild hypoxia and has some pulmonary edema that requires oxygen for two or three days will likely do well," Dr. Arteaga says. "But submersion beyond five minutes can cause irreversible effects on the brain."
She points out that water temperature can make a difference; very cold water slows the metabolism and therefore the need for oxygen, so the chances of recovery are better. The sooner spontaneous circulation returns, the better the outcome, too.
"If there is a low-grade submersion, where the child comes out of the water alert and never stops breathing, the outcome is much more positive than for a child in full cardiopulmonary arrest," Dr. Arteaga explains. "In cases of cardiopulmonary arrest, where the patient is intubated, spontaneous circulation returns slowly, and there have been seizures and a severe lack of oxygen to the brain, outcomes are worse. In these cases, patients who do survive may remain in a coma or vegetative state."
As in other cases of farm-related injuries, providers should offer education about preventive measures, including keeping ponds off-limits with fencing and locked gates and always supervising young children around any type of water — a baby can drown in a single inch of liquid.
For more information
Tester DJ, et al. Unexplained drownings and the cardiac channelopathies: A molecular autopsy series. Mayo Clinic Proceedings. 2011;86:941.