Overview
Definition
- Drowning: death secondary to asphyxia caused by submersion or immersion in a liquid medium
- Non-fatal drowning: survival, at least temporarily, after suffocation (or loss of consciousness) by submersion in a liquid medium
Epidemiology
- 3rd-most common cause of injury-related deaths worldwide
- 370,000 drowning deaths worldwide each year
- Peak incidence of drowning in the United States occurs between May and August.
- Important cause of childhood fatalities worldwide: Children aged 1–4 have the highest drowning rates.
- Non-accidental drowning deaths: male:female ratio of 2:1
- Most often affects low- and middle-income patients (91% of unintentional drowning deaths)
Risk factors
- Inadequate adult supervision
- Inability to swim (or overestimation of swimming ability)
- High-risk behaviors (especially in ages 15–25): use of alcohol and other drugs
- Hypothermia
- Concomitant trauma, stroke, or myocardial infarction
- Seizure disorder
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Diagnosis
Phyical exam
Clinical manifestations of drowning are due to the effects of hypoxemia.
Vital signs:
- Hypotension
- Hypothermia
- Hypoxemia
Respiratory changes:
- Water aspiration causes surfactant washout from the alveoli. This leads to:
- Pulmonary edema
- Respiratory insufficiency
- Acute respiratory distress syndrome (ARDS)
- May experience shortness of breath, crackles, and wheezing
- Even if the patient is initially stabilized, ARDS can develop insidiously over the next 72 hours.
Cardiovascular changes:
- Arrhythmias often occur secondary to hypothermia and hypoxemia.
- Tachycardia followed by sinus bradycardia
- May progress to atrial fibrillation
Neurologic changes:
Neuronal damage from hypoxia and ischemia causes:
- Cerebral edema
- Elevated intracranial pressure
- Hypoxic encephalopathy
- Seizures
Laboratory testing
- Arterial blood gas (ABG):
- Metabolic and/or respiratory acidosis
- Electrolyte abnormalities
- Blood alcohol level and drug toxicology panel:
- If warranted by context
- To determine if the cause was not organic
Imaging
Imaging is done via X-ray.
- Usually normal initially
- ARDS usually does not show on X-ray until later in course.
Management
While prevention is the most effective intervention, rapid resuscitation on-site is essential to improving patient prognosis.
1. Safely remove patient from the water and begin primary survey and resuscitation:
- Check for breathing:
- Normal breathing → supplement with oxygen (goal: oxygen saturation (SpO₂) > 90%)
- If no effective breathing → begin rescue breathing. (Note: This is the priority! Begin rescue breathing immediately and then check for pulse to determine if cardiopulmonary resuscitation (CPR) is needed.)
- Check for pulse:
- No pulse → begin immediate CPR
- If pulse is found but breathing is not normal → continue rescue breathing/oxygen supplementation.
- Intubate if:
- Patient is apneic or in respiratory distress
- Patient is unable to protect their airways
- Inability to maintain partial pressure of oxygen (PaO₂) > 60 mm Hg or SpO₂ > 90% despite the use of high-flow oxygen or noninvasive ventilation
- If hypothermic (core temperature < 33℃):
- Remove wet clothing.
- Begin rewarming.
2. Once patient has been resuscitated and stabilized, initiate secondary survey or transport to the nearest medical facility:
- Head-to-toe assessment for signs of trauma
- Asses for signs of substance abuse.
- Interview witnesses.
3. Once the patient has arrived at a medical facility, perform the following:
- Repeat or initial trauma evaluation
- Frequent vital signs and clinical reassessment
- Continuous oxygen supplementation and end-tidal carbon dioxide (CO₂) monitoring
- Deliver appropriate IV fluids to correct electrolyte disturbances.
- Continuous telemetry
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Outcome and Prevention
Outcome
The following are associated with poor prognosis:
- Submersion duration > 5 minutes
- Initiation of basic life support > 10 minutes
- Resuscitation duration > 25 minutes
- Age > 14 years
- Glasgow Coma Scale (GCS) < 5
- Arterial blood pH < 7.1 on presentation
Prevention
The best prevention is education on water safety:
- Gating access to swimming pools
- Providing adult supervision
- Not swimming alone
- Use of personal flotation devices
- Avoidance of alcohol and drugs while swimming
Differential Diagnosis
- ARDS: a severe inflammatory reaction of the lung that is characterized by the presence of pulmonary infiltrates due to alveolar fluid accumulation (without evidence suggestive of a cardiogenic etiology). The main finding of ARDS is respiratory failure. Chest X-ray usually shows diffuse bilateral lung infiltrates (“butterfly opacity”). Management depends mainly on treating the underlying etiology and maintaining adequate oxygenation, which may require intubation and mechanical ventilation.
- Pulmonary edema: a condition caused by excess fluid in the lungs. Pulmonary edema is a consequence of a disease process rather than a primary pathology. The condition is classified into cardiogenic and noncardiogenic based on the cause of the edema. Pulmonary edema is visible on chest X-ray.
References
- Drowning. (2020). WHO. https://www.who.int/news-room/fact-sheets/detail/drowning
- Tyler, Matthew D., et al. (2017). The Epidemiology of Drowning in Low- and Middle-Income Countries: A Systematic Review. BMC Public Health, 17(413). PubMed Central. https://doi.org/10.1186/s12889-017-4239-2