Residency · Residency · Emergency Medicine
Drowning and Submersion Injury
Introduction
Drowning is a leading cause of unintentional injury death worldwide, claiming approximately 236,000 lives annually. In the United States, it is the leading cause of death in children ages 1 to 4 and the second leading cause in children ages 5 to 14. The emergency physician must understand the pathophysiology of submersion injury, the principles of resuscitation, and the prognostic factors that guide management and family communication. The terminology has been simplified: the World Health Organization defines drowning as the process of experiencing respiratory impairment from submersion or immersion in liquid.
Terminology
Drowning is defined as the process of experiencing respiratory impairment from submersion or immersion in liquid, and the outcome may be death, morbidity, or no morbidity. The terms "near-drowning," "wet drowning," "dry drowning," and "secondary drowning" are outdated and should not be used, as they create confusion and have no pathophysiological basis. Submersion refers to the entire body, including the airway, being under water. Immersion refers to at least the face and airway being covered by water.
Pathophysiology
Sequence of Events
The drowning process follows a predictable sequence. Initial laryngospasm occurs upon water contact with the airway and may be brief or prolonged. This is followed by voluntary breath-holding until the breaking point. Aspiration of water into the lungs then occurs in the vast majority of cases, leading to hypoxemia and loss of consciousness, followed by continued aspiration and cardiac arrest from hypoxia.
Pulmonary Effects
Aspiration of as little as 1 to 3 mL/kg of water causes significant pulmonary dysfunction. Freshwater aspiration involves hypotonic fluid that is rapidly absorbed across the alveolar membrane, destroying surfactant and causing alveolar collapse, atelectasis, and intrapulmonary shunting. Saltwater aspiration involves hypertonic fluid that draws plasma into the alveoli, causing pulmonary edema and intrapulmonary shunting. In clinical practice, the distinction between freshwater and saltwater drowning has minimal impact on ED management, as both result in ARDS-like physiology with hypoxemia, decreased lung compliance, and ventilation-perfusion mismatch. Electrolyte disturbances from fluid aspiration are rarely clinically significant, as they would require massive aspiration volumes.
Hypothermia
Cold water submersion may induce rapid hypothermia, particularly in children who have a higher surface area-to-mass ratio. The dive reflex, triggered by cold water contact with the face, produces bradycardia, peripheral vasoconstriction, and apnea, preferentially shunting blood to the brain and heart. Hypothermia reduces cerebral metabolic demand, potentially providing neuroprotection. Intact neurological survival has been reported after prolonged cold water submersion of up to 60 minutes in extreme cases, particularly in children.
<image>Pathophysiology diagram of drowning showing the sequence from initial laryngospasm to water aspiration, illustrating the alveolar-level effects of both freshwater (surfactant destruction, alveolar collapse) and saltwater (osmotic fluid shift into alveoli, pulmonary edema) aspiration, with resulting ventilation-perfusion mismatch and hypoxemia</image>
Prehospital Management
Water rescue safety follows the principle of reach, throw, row, go, with rescuer safety being paramount. The victim should be removed from the water as quickly as possible. Rescue breathing should begin in the water if the rescuer is trained, though chest compressions require a firm surface. Cervical spine immobilization is indicated only if there is a mechanism suggesting spinal injury (such as diving, watercraft accident, or signs of trauma); routine c-spine immobilization in all drowning victims delays resuscitation and is not recommended. Early bag-valve-mask ventilation is the priority, as drowning is a hypoxic arrest and oxygenation and ventilation take precedence over chest compressions. Standard ACLS and PALS protocols apply with a focus on oxygenation and ventilation.
Emergency Department Management
Initial Assessment
The initial assessment focuses on ABCs with emphasis on airway management and oxygenation. Core temperature should be measured and rewarming initiated if the patient is hypothermic. Laboratory workup includes chest X-ray, arterial blood gas, CBC, BMP, lactate, and coagulation studies. The chest X-ray may be initially normal, as pulmonary edema and infiltrates may develop over 4 to 6 hours.
Respiratory Support
Supplemental oxygen should be provided for all symptomatic patients. Non-invasive positive pressure ventilation with CPAP or BiPAP is effective for moderate hypoxemia, recruiting collapsed alveoli and improving oxygenation. Endotracheal intubation and mechanical ventilation are indicated for severe hypoxemia, altered mental status, or respiratory failure. Lung-protective ventilation with tidal volumes of 6 to 8 mL/kg ideal body weight and PEEP titration to optimize oxygenation while avoiding barotrauma should be used, treating the condition as ARDS. ECMO should be considered for refractory hypoxemia or cardiac arrest unresponsive to conventional resuscitation, particularly in hypothermic patients.
Additional Management
Fluid resuscitation with IV crystalloid boluses addresses hypovolemia from capillary leak and cold diuresis. Bronchospasm is treated with inhaled beta-agonists. Empiric antibiotics are not routinely indicated, as aspiration pneumonia is uncommon unless the submersion occurred in grossly contaminated water; antibiotics should be given only if signs of infection develop. Steroids have no benefit and are not recommended. Targeted temperature management should be considered for comatose drowning patients who achieve return of spontaneous circulation, per post-cardiac arrest care guidelines.
Prognostic Factors
Favorable Prognostic Indicators
Favorable indicators include a submersion time of less than 5 minutes, cold water submersion (especially below 5 degrees Celsius), a witnessed event with rapid rescue, early effective CPR, rapid response to resuscitation with return of spontaneous circulation within 25 minutes, and pediatric age (given the greater potential for neurological recovery).
Poor Prognostic Indicators
Poor indicators include submersion time greater than 25 minutes in warm water, CPR duration greater than 25 minutes without return of spontaneous circulation, an initial cardiac rhythm of asystole (versus VF or PEA), fixed dilated pupils on ED arrival, arterial pH below 7.0 on initial ABG, and GCS of 3 at arrival.
Decision to Terminate Resuscitation
Warm water submersion exceeding 30 minutes with prolonged CPR greater than 25 to 30 minutes and persistent asystole is generally considered futile. For cold water submersion, extended resuscitation is warranted, and resuscitation should not be terminated until the patient is rewarmed to at least 32 to 35 degrees Celsius, following the principle that no one is dead until warm and dead. Medical command or an ECMO center should be contacted for guidance in borderline cases.
<image>Emergency department management algorithm for drowning victims showing initial assessment with simultaneous airway management, temperature measurement, and IV access, branching into pathways based on respiratory status (spontaneously breathing vs. respiratory failure) and neurological status (alert vs. comatose), with corresponding interventions and disposition decisions</image>
Disposition
Asymptomatic patients should be observed for at least 4 to 6 hours with serial examinations and pulse oximetry. If the patient remains asymptomatic with a normal chest X-ray and oxygen saturation, discharge is appropriate with return precautions. Symptomatic patients should be admitted for monitoring, and any patient requiring supplemental oxygen, having an abnormal chest X-ray, or with persistent symptoms warrants admission. Intubated patients or those with significant neurological impairment require ICU admission.
Prevention
Drowning prevention is far more effective than treatment. Pool fencing with self-closing, self-latching gates reduces drowning risk by 50 to 70 percent. Active adult supervision of children near water, with "touch supervision" for toddlers, is essential. Swim instruction for children is supported by evidence, with initiation recommended starting at age 1. Life jacket use for boating and open water activities and avoidance of alcohol around aquatic activities are additional critical prevention measures.
<image>Infographic on drowning prevention strategies showing four pillars: pool fencing with proper gate mechanisms, active adult supervision with arms-reach guidance for toddlers, age-appropriate swim lessons, and life jacket use for boating, with statistics on risk reduction for each intervention</image>
Clinical Pearls
Drowning is a hypoxic event, and early oxygenation and ventilation take priority over chest compressions in resuscitation. The freshwater versus saltwater distinction is clinically irrelevant in the ED, as both cause ARDS-like physiology. Routine c-spine immobilization is not indicated unless there is a specific mechanism suggesting spinal injury. Prophylactic antibiotics and steroids are not beneficial in drowning management. Cold water submersion victims, especially children, may survive prolonged submersion with intact neurological function, and resuscitation efforts should be extended with ECMO considered.
References
- Szpilman D, Bierens JJLM, Handley AJ, et al. Drowning. N Engl J Med. 2012;366(22):2102-2110.
- Topjian AA, Berg RA, Bierens JJLM, et al. Brain resuscitation in the drowning victim. Neurocrit Care. 2012;17(3):441-467.
- Mott TF, Latimer KM. Prevention and treatment of drowning. Am Fam Physician. 2016;93(7):576-582.
- Schmidt AC, Sempsrott JR, Hawkins SC, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of drowning. Wilderness Environ Med. 2016;27(2):236-251.
