- Wet vs. Dry Drowning
- Salt vs. Fresh Water
- Risk Factors
Drowning facts and prevention
- Drowning is defined by the World Health Organization (WHO) as "...the process of experiencing respiratory impairment from submersion or immersion in liquid."
- Drowning can be classified dry or wet, depending whether the voice box (larynx) goes into spasm and water is allowed to enter the lungs. Regardless of wet or dry, it does not change the treatment or outcome. The term "near" drowning used to refer to a victim who did not die; however, this term is no longer widely used.
- Instead, WHO prefers that the type of drowning be classified based on victim outcome:
- Did the person die?
- Did the person survive with no impairment (morbidity)?
- Or did the person survive with some physical or mental impairment.
- The causes of drowning tend to depend upon the age group of the victim.
- Infants most often drown in a bathtub.
- Children most often drown in a neighborhood or backyard pool.
- Teens and young adults (age 15-25) tend to drown in natural bodies of water like rivers and lakes.
- Factors that can be a significant factor in drowning are:
- Drowning tends to be a quiet, silent act. Victims do not usually thrash. Instead they expend significant energy trying to keep their head above water and may be too tired to shout for help; moreover, if water comes into contact with the vocal cords, they can go into spasm and prevent the victim from shouting for help. Often, the victim is found floating or at the bottom of the body of water or the tub.
- Drowning is described as a panicked experience. While victims may appear to be bobbing in the water with their head back, an expression of panic may be in their eyes.
- Tips to recognize a person that may be in danger of drowning begin with a reminder that while water is to be enjoyed, it is also a potentially dangerous environment and needs to be treated with respect.
- Try to be within arms' reach of small children and do not be distracted by other activities.
- Watch for anyone who seems to be swimming ineffectively or are bobbing in the water in an uncoordinated way, and whose head drops underwater. Victims may try to roll onto their back, but they may not always be successful.
- Victims rarely thrash; instead they may make feeble attempts at swimming and often repeat attempts to roll over onto their back, keeping their head above water. Too often, though, the first sign that the victims are in trouble is when their body is found floating and lifeless.
- Drowning is diagnosed based upon history. The victim is found struggling in the water and most often has difficulty breathing. Any person who has breathing compromised and has been immersed in water can be said to have drowned.
- Treatment for drowning begins with recognizing when victims are in trouble, and assessing whether they are awake and breathing. If there has been a traumatic event, like diving into shallow water, consider the risk of a broken neck and keep the neck immobilized. If victims are not breathing on their own or breathing ineffectively, administer rescue breathing. If there is no heartbeat, then start CPR. This is one situation when hands-only CPR is not adequate. All drowning victims need to be assessed in a hospital, so activate emergency services and call 911 immediately.
- Drowning is preventable.
- Learn how to swim, and swim with a buddy.
- Don't swim alone.
- Never leave infants alone in water, whether a bathtub, sink, etc.
- Supervise children when near water.
- Swimming pools should be fenced with locked gates and inaccessible to unsupervised kids.
- Always use water flotation devices during activities on the water, for example, kayaking, jet skis, and boats. The Coast Guard recommends and many states require wearing lifejackets.
- Drowning victims who arrive in the emergency department awake and breathing on their own have a good prognosis for recovery. Those patients who are not fully awake or who need support breathing have varying recoveries. Prognosis is better if the immersion time is shorter, and the water is cleaner and colder. Prognosis also is better for younger individuals compared with the elderly.
What is drowning and what are the statistics?
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. Prior to 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.
- 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 occur 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 happens during 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 spasm 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 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 persistent spasm of the larynx, and no water is aspirated (this was formerly known as "dry" drowning).
Does the type of drowning matter?
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. fresh water drowning.
Wet vs. dry 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 the 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 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 fresh water drowning.
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 water. Instead, most drownings are unwitnessed and the person is found floating or submerged in the water.
For those who are alive, they may be anxious, confused, and short of breath. Brain function and lung function are the main concerns in drowning victims.
Young children may have a mammalian diving reflex that occurs when 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.
When should one seek medical care for drowning?
All individuals who are victims of drowning, even if they have no symptoms, should be evaluated by a health care professional. Sometimes, subtle information will be revealed that may make the diagnosis of an underlying medical condition.
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 prior to being found?
- Was there any potential trauma associated with the drowning (diving/falling into the water/falling out of a boat, falling through ice)?
- Was there 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?
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 examination will also be performed.
How is drowning treated?
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.
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.
What is the prognosis for a drowning victim?
The prognosis for many drowning victims is poor. The brain does not tolerate lack of oxygen well and the amount of potential damage is dependent upon the time the patient spends hypoxemic in the water.
The key to the treatment of drowning is prevention.
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World Health Organization. Drowning.