Near drowning: fresh water, sea water or cold water – is there any difference? Goran Popić Pulmonary Division, Dpt of Medicine, General Hospital, Pula
Near drowning is the survival of a drowning event and can lead to serious secondary complicationsincluding death.
Near drowning salvage at the moment of birth: • At birth the airways are filled with fluid. • Release of compression after passage through the birth canal causes air to be sucked in. • Large force is necessary during the first inspiration to overcome the surface tension. • After that – large quantities of surfactant are released by the pneumocytes II.
The principal physiologic consequences of immersion are persistent hypoxemia and resultant ischemic acidosis. A surprising degree of hypoxia can exsist without clinical signs.
Near drowning causes lung tissue hypoxia and sequential changes as in: • high altitude pulmonary edema • “mechanical” (strangulation etc.) causes of pulmonary edema • avalanche victims • acute lung injury / ARDS
Question: Near drowning in fresh water (hypotonic) ... and the meaning of → • surfactant destruction? • serum electrolyte imbalances? • hemolysis? Answer: UNIMPORTANT ! (in terms of management)
Question: Near drowning in sea water (hyperosmolar) ... and the meaning of → • fluid exudation into the alveoli? • surfactant washout? • hyperosmolar injury of the epithelium? • serum electrolytic changes? Answer: UNIMPORTANT ! (in terms of management)
Question: Near drowning in cold water? Definition: cold water = less than 21˚ C Answers: • Bad: difficult swimming (muscular weakness), impaired judgement, core hypothermia and VF • Good: hypothermia and neuroprotection, the mammalian diving reflex
The mammalian diving reflex is triggered by cold water contacting the face (ophthalmic division of the trigeminal nerve) and causes: • Apnea • Bradycardia • Peripheral vasoconstriction • Thoracic blood shift and filling up alveoli with plasma
Near drowning in cold water, prognosis: • Age of victim – the younger the better • Water temperature – the colder the better • Victim’s struggle – the more the worse Note: if a person has been under water for LESS THAN ONE HOUR, full resuscitative efforts should be employed
General Hospital, Pula: 46 consecutive cases of near drowning victims, retrospective review: • 78% males • 75% swimmers • 72% tourists • In some cases - incapatitation arising from alcohol, heart attack, seizure, stroke • In others – barotrauma or blackout on ascent from deep dive • No signs of atelectasis seen on the x-rays • Two deaths in hospital
Treatment of near drowning victims, some important points: • Immediate on site CPR is the key to increase the chance of survival. • DO NOT DO any specific maneuvers (Heimlich) to expel water from the lungs. • ED observation for 8 hours to screen for those requiring hospital admission. • Arterial blood gas analysis and chest x-rays are the most reliable parameters. • Warning of any pyrexial illness after discharge (secondary pulmonary infection).