Near drowning occurs when patients survive at least temporarily after water immersion. Near drownings are relatively common, usually involve children younger than age 4 years or young adults, and present dramatically to the emergency department.

Traditionally, major emphasis has been placed on whether immersion in fresh or salt water occurred; the incidence of hemolysis, electrolyte disturbances, intravascular volume changes, and prognosis were said to be determined by the osmotic nature of the aspirated fluid. Although experimentally valid, these considerations have more recently been deemphasized.

When immersion occurs, a period of breath holding is followed by involuntary inspiration; aspiration of water, which may be contaminated with bacteria and other particulate matter, usually follows. Interestingly, however, approximately 15% of patients who die as a result of drowning do not aspirate. In these patients, intense and immediate laryngospasm prevents aspiration; death occurs as a result of asphyxia (“dry-drowning”).

A variety of pulmonary injuries are seen in patients who aspirate during immersion; these include varying degrees of interstitial and alveolar edema, injury to the alveolar capillary membrane, loss of surfactant resulting in alveolar collapse, obstruction of airways secondary to any variety of particulate matter, and a number of delayed complications resulting from bacterial deposition within the lung. If significant, singularly or collectively, these abnormalities produce hypoxemia, which in approximately 20% of near-drowning victims causes profound neurologic damage despite adequate resuscitative efforts.

Clinically, patients may present totally without symptoms; with cough and slight dyspnea; or with apnea, hypothermia, and coma. In patients with cerebral anoxia, the prognosis for recovery of normal neurologic function is not well understood. Important prognostic factors include