Write a short note on drowning and near-drowning.

Definition

Drowning is defined by WHO as the process of experiencing respiratory impairment from submersion or immersion in liquid. Outcomes are classified as death, survival with morbidity, or survival without morbidity. The older terms "near-drowning", "wet" and "dry drowning" and "secondary drowning" are no longer recommended, though "near-drowning" remains in common examination use for survival after a submersion event.

Drowning is a leading cause of accidental death, particularly in children, and in India is associated with open wells, ponds, rivers, canals, flooding and religious bathing, frequently compounded by inability to swim and by alcohol in adults.

Pathophysiology

1. Submersion causes breath-holding, then involuntary laryngospasm as water contacts the larynx.

2. Progressive hypoxia leads to loss of consciousness; laryngospasm relaxes and water is aspirated in most victims.

3. Aspirated water — whether fresh or salt — washes out and inactivates surfactant, causing alveolar collapse, atelectasis, ventilation-perfusion mismatch, intrapulmonary shunting and non-cardiogenic pulmonary oedema (ARDS).

4. Hypoxia is the final common pathway, causing cardiac arrest, hypoxic-ischaemic brain injury and multi-organ failure.

Clinical Features

• Ranges from an asymptomatic patient with a history of submersion to cardiac arrest.
• Respiratory: cough, breathlessness, wheeze, crackles, frothy pink sputum, cyanosis, respiratory failure. Deterioration may be delayed by several hours as surfactant depletion evolves.
• Neurological: confusion, agitation, seizures, coma; hypoxic-ischaemic encephalopathy determines long-term outcome.
• Cardiovascular: arrhythmias, hypotension, cardiac arrest — most commonly asystole or pulseless electrical activity secondary to hypoxia.
• Hypothermia — frequent, especially in cold water and in children; it complicates resuscitation but may also be protective to the brain.
• Associated injuries — always consider cervical spine injury where there has been a dive, a fall, or a shallow-water accident, and consider alcohol, drugs, seizure, arrhythmia (long QT), myocardial infarction or deliberate self-harm as the precipitating cause of the submersion.

Investigations

Arterial blood gas, pulse oximetry, chest X-ray (which may lag behind the clinical picture and be normal initially), electrolytes, renal function, blood glucose, core temperature, ECG, and cervical spine imaging where indicated. Screen for alcohol and drugs, and consider CT head where consciousness does not improve as expected.

Management

At the scene:

• Rescue without becoming a second victim; remove from the water keeping the cervical spine protected where injury is possible.
• Start rescue breathing as early as possible — even in the water where trained — because hypoxia is the problem. This is the one arrest scenario where ventilation takes priority, and standard compression-only CPR is not appropriate.
• Do not attempt to drain water from the lungs — abdominal thrusts and postural drainage are ineffective, delay ventilation and risk aspiration of gastric contents.
• Begin CPR with rescue breaths first; continue resuscitation even in an apparently lifeless, cold patient.

In hospital:

• Oxygenation and ventilation — high-flow oxygen; non-invasive ventilation or intubation with PEEP, which is key to recruiting collapsed alveoli and treating pulmonary oedema.
• Rewarming for hypothermia; correct acidosis, electrolytes and glucose.
• Circulatory support with fluids and inotropes as needed.
• Neuroprotection — maintain normoxia, normocapnia, normoglycaemia and normothermia; treat seizures; targeted temperature management may be considered after cardiac arrest.
• Antibiotics are not given prophylactically — reserve them for established infection, guided by cultures. Consider unusual organisms with contaminated or stagnant water aspiration.
• Observation: any symptomatic patient, or one with abnormal auscultation, hypoxia or an abnormal chest X-ray, must be admitted and observed for at least 6–8 hours for delayed pulmonary deterioration. A fully asymptomatic patient with normal examination, saturation and chest X-ray after a period of observation may be discharged with clear advice to return if breathlessness or cough develops.