Drowning

Basics

Definitions:
- Drowning: “A process resulting in primary respiratory impairment from submersion or immersion in a liquid medium”
  - Fatal drowning: Death at any time as a result of drowning
  - Nonfatal drowning: Survival after aspiration of fluid into the lungs or after a period of asphyxia secondary to laryngospasm
- Water rescue: Any submersion or immersion incident without evidence of respiratory impairment
Scenario of drowning:
- Now thought all drowning victims aspirate some amount of liquid
- Previously classified as “wet” and “dry” drowning:
  - “Wet” drowning (90%): Aspiration of small amount of liquid into the lungs
  - “Dry” drowning (10%): Laryngospasm secondary to the presence of liquid in the oropharynx or larynx
- End result: Hypoxia
- No significant difference between freshwater and saltwater submersion
Pathophysiology:
- Aspiration:
  - Small volume of water
  - Decreased lung compliance causing ventilation/perfusion mismatch and intrapulmonary shunting
  - No significant electrolyte changes
  - Grossly contaminated water: Risk for pulmonary infection
- Hypoxemia:
  - Metabolic lactic acidosis
  - Multisystem organ dysfunction
  - Noncardiogenic pulmonary edema
  - Myocardial dysfunction (arrhythmias)
  - Coagulation abnormalities (disseminated IV coagulation)
  - Renal failure (usually acute tubular necrosis)
  - Cerebral hypoxia: Cerebral edema, increased intracranial pressure

Pediatric Considerations

Hypothermia:
- More common in young children
- Larger body surface-to-mass ratio
- Decreases the metabolic rate
- Survival with full recovery is possible (neuroprotective)
Diving reflex:
- Young children are more susceptible
- Triggered by submersion of face in cold water
- Bradycardia ensues: Redistribution of blood flow to the heart and brain
- Delays onset of hypoxia-related damage

ALERT
Risk factors:

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