Description

• 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

• 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

• Lack of proper supervision
• Alcohol or other drug abuse
• Limited swimming ability or exhaustion
• Trauma
• Seizure disorder
• Risky behavior
• Pre-existing or concomitant medical problem
• Attempted suicide
• Poor education