Drowning and immersion injury

Abstract

Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid. The primary determinant of outcome is the occurrence of circulatory arrest, indicative of prolonged asphyxia. Immediate (bystander) cardiopulmonary resuscitation efforts are crucial to outcome. If a victim is retrieved from the water and resuscitated, widespread organ dysfunction can be expected. The pathophysiology is intimately related to the multi-organ effects of hypoxaemia. Individuals who drown in cold water (below 20°C) rapidly develop hypothermia, which may confer some neurological protection. There are no factors that accurately predict death or severe neurological impairment in cold water drowning. There are reports of intact recovery despite extreme physiological derangement. No specific hospital interventions have been shown to alter outcome. Therapeutic goals are initial resuscitation, and supportive treatment for acute lung injury and other organ dysfunction. Secondary brain injury must be prevented by providing optimal conditions for cerebral oxygen delivery. Following return of spontaneous circulation, a controlled restoration of body temperature towards normal is desirable. The World Congress on Drowning (2002) recommended that victims who remain comatose be treated with induced mild hypothermia (32-34°C) for 12-24 hours; this requires sedation, intubation and ventilation. A quarter of patients admitted to hospital alive at 24 hours ultimately die, and a further quarter have a poor neurological outcome.