Every year, approximately 90 people in Norway die from drowning. It is one of the leading causes of accidental death worldwide, affecting all age groups, although children are particularly vulnerable. A good understanding of what drowning entails and how it should be managed is crucial to saving lives and minimizing permanent injuries in survivors.

What is drowning – definitions

According to the World Health Organization (WHO), drowning is defined as respiratory impairment resulting from submersion or immersion in liquid (1). It is worth noting that the definition applies regardless of whether the patient survives or not: we distinguish between fatal drowning and non-fatal drowning, in the same way we use the term cardiac arrest regardless of whether the patient survives or not. Being submerged in water without leading to respiratory impairment is not defined as drowning.

WHO classifies non-fatal drowning by severity: mild impact (conscious, but coughing or slightly short of breath), moderate impact (clear breathing difficulties or disorientation), and severe impact (respiratory arrest and/or unconsciousness). This simple classification helps us quickly prioritize appropriate measures.

Outdated terms for drowning

Near-drowning

The term near-drowning is no longer used in modern terminology. Either the patient has drowned, meaning they have experienced respiratory impairment, or they have not drowned. Submersion without symptoms of respiratory impairment is therefore not defined as drowning. The term near-drowning is often mistakenly used in conjunction with the terms below.

Dry drowning

Previously, cases where patients drowned without visible water in the lungs upon autopsy were described as dry drowning. This phenomenon is caused by laryngospasm (strong contraction of the vocal cords) which prevents both water and air from reaching the lungs. Completely "dry lungs" are only seen in a small percentage of forensic autopsies (2).

Acute treatment for drowning is identical, regardless of whether the lungs appear "dry" or "wet". The term dry drowning should therefore be avoided, as it can create a false impression that individuals without fluid in their lungs after a brief submersion may risk serious complications at a later time. Any laryngospasm almost always occurs in conjunction with the event itself or immediately afterwards, and then gives immediate and clear symptoms.

Secondary drowning and delayed drowning

Secondary drowning or delayed drowning is based on a medical myth—the notion that life-threatening complications can arise hours after a submersion event in a person who was completely asymptomatic immediately afterwards. There are no documented cases of this ever occurring (2, 3).

However, it is important to be aware that patients who already have symptoms after a drowning incident, such as persistent coughing or mild shortness of breath, may experience worsening conditions over the next few hours. This is due to gradual alveolar collapse (atelectasis), shunting, and increasing pulmonary edema as a result of alveolar damage and surfactant washout. The point is that this presupposes that water was present in the lungs during the incident, and that symptoms in such cases will be present from the outset.

Alternatively, pulmonary edema may develop as a result of forceful breathing efforts against a closed airway (laryngospasm or flaccid tongue), which we call "negative pressure pulmonary edema." These patients will also have clear symptoms when they are removed from the water.

Pathophysiology of drowning

Lungs and oxygenation

Aspiration of water damages the lungs both immediately and over time. Water that reaches the alveoli, the small air sacs in the lungs where oxygen uptake occurs, washes away surfactant. Surfactant is important for keeping the alveoli open, and its loss leads to alveolar collapse (atelectasis). This results in poor oxygen uptake and a condition called alveolar shunt, where blood passes through lung tissue without being oxygenated.

Another serious complication is ARDS (Acute Respiratory Distress Syndrome), which results from damage to the alveolar membrane. This damage makes the membrane more permeable, allowing fluid from the bloodstream to leak into the alveoli and cause pulmonary edema. This impedes gas exchange and causes significant breathing difficulties. If we disregard drowning, pulmonary edema most often develops due to severe heart failure, but here it is the destruction of the alveolar membrane that is the cause, not the heart!

Water quality also plays a role: drowning accidents in water contaminated with sewage, oil, or other chemicals carry a higher risk of severe lung infections and ARDS. Chlorinated pool water generally entails a lower risk of infection, but high chlorine concentrations can irritate lung tissue.

Central nervous system

The brain is highly sensitive to oxygen deprivation. Even short-term lack of oxygen in the blood (hypoxemia) can lead to brain cell death and permanent damage to brain tissue. This can result in death or severe neurological long-term complications. A common and serious complication after such a brain injury is cerebral edema, which causes increased pressure in the head, potentially reducing blood flow to the brain and, in the worst case, leading to brain death.

Heart and circulation

The heart is also vulnerable to oxygen deprivation. The most common cardiac rhythm in cardiac arrest due to drowning is pulseless electrical activity (PEA), a non-shockable rhythm. Nevertheless, a defibrillator should always be used if available, as both ventricular fibrillation and ventricular tachycardia can occur.

Hypothermia

Hypothermia is common in drowning incidents, and the low temperature plays a dual role. On one hand, as core body temperature drops, the cells' oxygen demand decreases, and the brain can tolerate longer periods of oxygen deprivation. This explains why patients rescued from icy water after a long time can still survive. On the other hand, hypothermia increases the risk of cardiac arrhythmias and can cause fluid loss through what is known as cold diuresis. Hypothermia causes vasoconstriction in the skin, leading to centralization of blood volume. The body misinterprets this as an excess of fluid, which it eliminates via the kidneys.

If a person is hypothermic, they can survive prolonged submersion and extended CPR with a good neurological outcome. It is therefore often said that "a drowned patient is not dead until they are warm and dead."

Drowning in freshwater vs. saltwater

Traditionally, there has been much focus on whether the patient drowned in freshwater or saltwater, but in practice, this matters little for assessment and treatment. Freshwater is hypotonic, meaning it contains fewer dissolved particles than blood. In drowning, water will therefore be drawn from the alveoli into the bloodstream, because fluid is always drawn towards where there is the highest concentration of dissolved substances, which we call osmosis. Drowning in freshwater can therefore lead to a risk of destruction of red blood cells (hemolysis) and low sodium content in the blood (hyponatremia).

Saltwater, on the other hand, is hypertonic and draws fluid in the opposite direction, from the bloodstream to the alveoli, which can potentially contribute to the development of pulmonary edema, with fluid in the alveoli. Freshwater is also assumed to inactivate surfactant more effectively than saltwater, which can increase the risk of alveolar collapse, atelectasis (4).

Both are theoretically interesting, but treatment is always based on symptoms and findings. Correction of sodium and other electrolytes is always done based on blood gas or blood tests.

Clinical presentation and assessment of drowning

Drowning patients present very differently, from only mildly affected to lifeless. Patients who are only mildly affected may worsen over the next few hours. Symptomatic patients should therefore be observed in a hospital with SpO₂ monitoring and repeated clinical assessment, as increasing atelectasis and pulmonary edema can develop during this time.

Patients who have been submerged but are completely asymptomatic, without cough, shortness of breath, or impaired consciousness, and have a normal clinical examination, do not need to be admitted, but should not be left alone. They should be given clear instructions to seek medical attention immediately if symptoms develop.

Also remember that the underlying cause of the patient's submersion, such as low blood sugar, seizures, or head injury, may require follow-up.

Treatment of drowning

First aid

The priority is always to establish a clear airway and initiate ventilation early. In cases of unconsciousness and absence of normal breathing, CPR should be started immediately. Drowning differs from other causes of cardiac arrest in that oxygen deprivation, not primarily heart disease, is the cause. Therefore, we always start with five rescue breaths before proceeding to 30:2 compressions. Do not spend time trying to drain water from the lungs:

Quickly dry the chest and use a defibrillator as soon as it is available; it will analyze the rhythm and determine the need for a shock. Call 113 if the patient has been brought to shore; call 110 if the patient is still in the water and water rescue is needed.
Unconscious patients with normal breathing should be placed in the recovery position.

Neck stabilization

Be cautious with the neck if you are not entirely sure of the incident's course, especially if you suspect a diving accident or other injury. However, neck stabilization should never delay or compromise life-saving measures such as securing a clear airway and performing effective CPR.

Pre-hospital emergency medical treatment

Outside the hospital, the ABCDE principles are followed:
A – Airway: Airway management according to skill level. Intubation has not been shown to improve long-term survival with good neurological outcome in cardiac arrest due to drowning.
B – Breathing: 100% oxygen initially for all with cardiac arrest and otherwise until the situation is stabilized. The prehospital goal is SpO₂ over 90% (5). In case of signs of atelectasis, shunting or pulmonary edema (ARDS), consider PEEP valve on mask-bag, or CPAP/BiPAP in conscious, spontaneously breathing patients.
C – Circulation: Initiate advanced cardiac life support (ACLS) immediately in cases of cardiac arrest. If core body temperature is below 32°C and cardiac arrest is ongoing, transport to a hospital with ECMO capability should be considered in consultation with a specialist. Medications during ACLS are generally not recommended when core body temperature is below 30°C. More than 3 shocks are also not recommended at temperatures below 30°C, but should be resumed at higher temperatures. Between 30–35°C, medications are given only every 5 minutes, compared to every 3 minutes normally (6).
D – Disability: Assess level of consciousness regularly; measure blood sugar.
E – Exposure and temperature: Measure core temperature early and repeatedly. Actively warm hypothermic patients.

In the hospital

The patient is often received by a trauma team and systematically assessed according to the ABCDE principles. The assessment typically includes chest X-ray, arterial blood gas, laboratory tests with electrolytes, liver and kidney function tests, coagulation, serum ethanol, and blood glucose. ECG is always performed; echocardiography is considered in hemodynamically affected patients. CT scan of the head in cases of persistent altered consciousness or suspected head injury.

Patients with persistent mild respiratory distress can be treated with high-flow nasal oxygen (HFNO) or CPAP/BiPAP. Intubation and mechanical ventilation may be necessary in more severe cases.

Antibiotics are not routinely given but may be considered for drowning in heavily contaminated water (sewage).

Drowning in children – special considerations

Children are particularly vulnerable to drowning accidents and cool down faster than adults due to their large body surface area relative to body weight and less subcutaneous fat (7).

The principles of first aid and treatment are essentially the same: Always start with five rescue breaths when initiating CPR. For laypersons, 30:2 compressions are continued as for adults. Healthcare professionals use 15:2 for children after the first five rescue breaths. For infants (under one year), the head is held in a neutral position, and breaths are given over both the nose and mouth simultaneously. It is also recommended to place a small blanket or cloth under the shoulders to make it easier to achieve a neutral position and clear airways in infants.

In cases of drowning without cardiac arrest, there is a low threshold for consulting with a pediatrician regarding hospital admission for observation, even with mild symptoms. Children with severe incidents may require ECMO.

Prognosis of drowning

The most important prognostic factors in drowning are time underwater, water temperature, and time to effective CPR. Shorter submersion time and colder water generally lead to a better prognosis. Patients who are rescued from water with spontaneous circulation and adequate respiration have a good prognosis.

The content of this article is for informational purposes only and should not be considered medical advice. Before performing medical procedures, you must have undergone proper training, education, and certification. The article may contain errors, and we do not assume responsibility for patient treatment or outcomes. Always consult with qualified healthcare professionals for medical advice and training. The use of this article does not replace professional medical training and certification.

References

World Health Organization. Drowning. Geneva: WHO; updated December 13, 2024 [cited May 2026]. Available from: https://www.who.int/news-room/fact-sheets/detail/drowning
Szpilman D, Sempsrott J, Webber J, et al. 'Dry drowning' and other myths. Cleve Clin J Med. 2018;85(7):529–35.
American Red Cross. Debunking the existence of dry or delayed/secondary drowning. Updated 2024. [cited May 2026] Available from: https://www.redcross.org/take-a-class/resources/articles/dry-or-delayed-secondary-drowning?srsltid=AfmBOoph-KvGFPwchgfjlq1HPhoAJrRqAuxzvkJLlHFyrMYBwl_OmjZs
Michelet P, Dusart M, Boiron L, et al. Drowning in fresh or salt water. Eur J Emerg Med. 2019;26(5):340–4.
Johansen IH, Blinkenberg J, red. Drowning. In: Emergency Handbook. Oslo: Gyldendal Akademisk / NKLM; [cited May 2026]. Available from: https://www.lvh.no/naar-det-haster/drukningsulykker/drukning
National Centre for Traumatology. Clinical guideline for the management of accidental hypothermia. Oslo: NKT-Traume; 2019.
Rajka T, Heltne JK. Drowning. In: Acute Pediatric Guide. Helsebiblioteket; 2013. [cited May 2026] Available from: https://www.helsebiblioteket.no/innhold/retningslinjer/pediatri/akuttveileder-i-pediatri/1.akutte-prosedyrer-og-tilstander-inkludert-ulykker/1.11-drukning