Drowning (Dry, Wet, Near)

Medically Reviewed on 3/20/2023

What is drowning?

Types of, causes of accidental drowning, plus symptoms, treatment, wet, dry and medical definition
The best treatment for drowning is the prevention of causes.

According to WHO, "Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid." The possible outcomes of drowning are classified as death, morbidity (the development of disability or injury), and no morbidity.

This simple definition was agreed upon at the 2002 World Congress of Drowning held in Amsterdam. Before that meeting, some definitions and classifications of drowning were not necessarily well defined, and their meanings were subject to a variety of interpretations by different countries and health organizations. While some people still try to sort drowning events into categories (for example wet vs. dry, primary vs. secondary, fatal vs. nonfatal), these terms may or may not adequately describe a patient's situation, the effects of drowning on their body, or the potential outcome.

How many people drown each year?

Statistics

  • Drowning is the third most common cause of accidental death worldwide, accounting for 7% of all injury-related deaths.
  • According to WHO, more than 350,000 people die every year from drowning. This number significantly underestimates the actual number because they do not include those who drown in floods, boating, or water transport accidents.
  • Almost half of all drowning in the world occurs in China and India.
  • The death rate from drowning does not reflect the potential morbidity (disability) due to brain injury for those who survive a drowning episode.
  • Most countries do not keep nonfatal drowning statistics.

What are the stages of drowning?

Drowning occurs when water comes into contact with the larynx (voice box).

  • After an initial gasp, there is a period of voluntary breath-holding.
  • This is followed by spasms of the larynx and the development of hypoxemia (hypo=low + ox=oxygen + emia=blood), or decreased levels of oxygen in the bloodstream.
  • Lack of oxygen causes aerobic metabolism to stop, and the body becomes acidotic. If not corrected quickly, the lack of oxygen in combination with too much acid may lead to problems with the electrical conduction system of the heart (cardiac arrest) and a lack of blood supply to the brain.
  • As body function declines, aspiration may occur as the larynx relaxes, allowing water to enter the lungs. However, up to 20% of drowning victims have a persistent spasm of the larynx, and no water is aspirated (this was formerly known as "dry" drowning).

What are the types of drowning?

There have been a variety of theories reported regarding the potential responses of the body to different drowning situations. Most discuss dry vs. wet drowning and salt vs. freshwater drowning.

Is dry drowning the same as wet drowning?

Most drownings are unwitnessed, and the victim is found floating. While only a small amount of aspirated water is required to cause significant problems with lung function, it is the prolonged submersion time and lack of breathing that causes complications due to hypoxemia.

Approximately 10% to 20% of drowning victims have dry drowning with no water found in the lungs at autopsy, but even most wet drowning victims have less than 4cc/kg of water found in their lungs. For a 50-pound child, this amounts to less than 3 ounces of water.

Salt vs. fresh water drowning

In the lung, the breathing tubes (trachea, bronchi, bronchioles) branch into smaller and smaller segments until they end in an air pocket called an alveolus (plural alveoli). This is part of the lung where air and red blood cells in capillary blood vessels come near enough to allow the transfer of oxygen and carbon dioxide between the two. Alveoli are covered with a chemical called surfactant that allows the air pocket to open and close easily when breathing occurs.

When fresh water enters an alveolus, it destroys the surfactant and causes the alveoli to collapse, unable to open with breathing. A mismatch can develop where blood is pumped to parts of the lung where no oxygen is available to be absorbed. This may lead to a decrease in the concentration of oxygen in the blood called a ventilation-perfusion mismatch.

Salt water doesn't destroy surfactant; rather it washes it away and damages the membrane between the alveolus and the capillary blood vessel. Once again, the body sends blood flow to areas of the lung that aren't able to provide it oxygen, and hypoxemia occurs.

Regardless of the type of water, lung function is compromised because of the lack of surfactant, and the effect it has on lung function. In some circumstances, electrolyte abnormalities may occur with freshwater drowning.

SLIDESHOW

Summer Hazards: Avoid These 13 Summer Health Risks See Slideshow

What are the risk factors of drowning?

There are two peak ages for drowning: children aged younger than 4 and young adults aged 15 to 25.

  • Infants less than 1-year-old most often drown in bathtubs.
  • Children younger than age 5 most commonly drown in residential swimming pools.
  • Young adults tend to drown in larger bodies of water (for example, rivers and lakes). Neck fractures caused by diving into shallow water are associated with drowning in this age group. Alcohol is also implicated in up to 50% of drownings in this age group.
  • Medical emergencies that occur in the water also can lead to drowning. These may include, among others, seizures, heart attack (myocardial infarction), sudden cardiac death, and hypoglycemia (low blood sugar in a person with diabetes).

What are the symptoms of drowning?

The consequences and symptoms of drowning vary widely. A drowning victim may show no symptoms and have no complaints, or may be found dead.

It is the rare person who is found thrashing in the water. Instead, most drownings are unwitnessed and the person is found floating or submerged in the water.

Those who are alive may be anxious, confused, and short of breath. Brain function and lung function are the main concerns in drowning victims.

Special situations

Young children may have a mammalian diving reflex that occurs when a drowning occurs in very cold water. When suddenly immersed in cold water less than 68 F (20 C), victims can stop breathing, slow their heart rate dramatically, and shunt all the blood flow to the heart and brain. Though not common, these children may be resuscitated and return to normal function. Cases of survival have been reported, even after being underwater for an hour.

How is drowning diagnosed?

The initial evaluation of any drowning victim will begin with a history of the events.

  • How old is the patient?
  • Are there any underlying medical problems?
  • Does the patient take any prescription or non-prescription medications? Is there a history of drug or alcohol use?
  • How long was the person unattended before being found?
  • Was there any potential trauma associated with the drowning (diving/falling into the water/falling out of a boat, falling through the ice)?
  • Was there a loss of consciousness before, during, or after the drowning episode? Did the patient have a witnessed seizure? Did the person complain of chest pain and was he or she a victim of sudden cardiac arrest before falling into the water?
  • Has there been any change in behavior after being removed from the water?
  • Has the person had vomiting?

A physical examination will begin with taking and monitoring the vital signs (the ABCs will be evaluated -- airway, breathing, and circulation). Careful examination of the whole body will be required, especially focusing on the neurological examination to assess brain function. Lung and heart examinations will also be performed.

If a trauma or a diving injury is a consideration, the neck and spine may be immobilized to protect against potential spinal cord damage.

Laboratory and X-ray testing will be utilized depending on the situation and potential injuries.

What is the treatment for drowning?

Treatment begins at the water's edge. The American Heart Association recommends, if possible, sending one person to activate emergency medical services and to call 911. Send another person to bring an automatic external defibrillator (AED) to the victim's side.

If no pulse can be identified and the patient is not breathing, start CPR. Drowning is one of the special situations where hands-only CPR is NOT indicated. If there is a potential for a neck injury, take special care to prevent further injury to the victim by keeping the neck and body in alignment.

If the patient is breathing but not awake, place the person on his or her side in the rescue position to prevent aspiration if vomiting should occur.

  • Further treatment by EMTs, paramedics, and staff at the hospital will depend upon the severity of the symptoms. Those patients who have no symptoms may require nothing more than observation.
  • Those who are in cardiopulmonary arrest will likely undergo CPR with attempts to restore a regular heart rhythm and heartbeat.
  • Those patients who have symptoms related to the function of their heart, lung, or brain will need further evaluation and treatment tailored to their specific circumstances and situation.
  • And, unfortunately, for those who are found dead with no potential for resuscitation, further treatment or evaluation may not be indicated.

What are the complications of drowning?

  • Hypoxemia causing brain damage is the major complication in drowning victims who do not die.
  • Direct lung tissue damage caused by water aspirated into the lung can also occur and may lead to pneumonia and acute respiratory distress syndrome (ARDS).
  • If the drowning occurs in colder water, there is the risk of hypothermia or a drop in core body temperature.
  • Drowning may occur as a consequence of injury or illness. For example, cervical spine fractures (broken neck) due to diving injuries may result in breathing problems and subsequent drowning. Drowning can occur as a result of syncope or loss of consciousness in the water, due to a variety of medical conditions including heart attack and seizure.

What is the prognosis for a drowning victim?

The prognosis for many drowning victims is poor. The brain does not tolerate a lack of oxygen well and the amount of potential damage is dependent upon the time the patient spends hypoxemic in the water.

Even if the brain survives, acute respiratory distress syndrome (ARDS) may cause significant short- and long-term problems as the lungs try to recover from their injuries.

The key to the treatment of drowning is prevention.

How can drowning be prevented?

Most drownings are preventable, and simple steps can be taken to help with water safety.

  • Learn how to swim.
  • When in the water, use the buddy system.
  • Do not use alcohol or drugs when swimming or boating.
  • Supervise children closely around water and make certain they are the focus of your attention. Even bathtubs and buckets full of water can be dangerous.
  • Swimming pools should have barriers (fences, gates, alarms) to prevent children from entering unattended.
  • Learn CPR.

Subscribe to MedicineNet's Skin Care & Conditions Newsletter

By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time.

Medically Reviewed on 3/20/2023
References
Riva, G., et al. Survival in Out-of-Hospital Cardiac Arrest After Standard Cardiopulmonary Resuscitation or Chest Compressions Only Before Arrival of Emergency Medical Services. Circulation 139.23 4 June, 2019:2600-2609.
<https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.038179>

World Health Organization. Drowning.
<http://www.who.int/violence_injury_prevention/other_injury/drowning/en>