What is the most likely complication over the next 36 hours for a 17-year-old boy who had a near-drowning incident in freshwater?

Acute Respiratory Distress Syndrome is the Most Likely Complication Following Near-Drowning

Acute respiratory distress syndrome (ARDS) is the most likely complication to develop within 36 hours in this 17-year-old boy who experienced submersion in freshwater with loss of consciousness.

Pathophysiology of Freshwater Drowning

When a person is submerged in freshwater, several pathophysiological changes occur that significantly impact the respiratory system:

• Aspiration of freshwater causes surfactant washout and inactivation
• Hypoxemia develops due to ventilation-perfusion mismatch
• Pulmonary hypertension and shunting contribute to worsening oxygenation
• Inflammatory cascade is triggered, leading to alveolar damage

The drowning process begins with voluntary breath-holding, followed by laryngospasm, and eventually, when the victim's arterial oxygen tension drops significantly, the victim actively breathes liquid 1. The amount of liquid inhaled varies between victims, but changes in the lungs occur rapidly.

Timeline of Respiratory Complications

In this case, several risk factors point to ARDS as the most likely complication within 36 hours:

1. Submersion duration of 3 minutes - Duration underwater is the most important predictor of outcome in drowning as it represents the amount of anoxia 1
2. Initial cyanosis - Indicates significant hypoxemia
3. Loss of consciousness - Suggests severe hypoxic insult
4. Freshwater submersion - Causes surfactant washout and inactivation

Research specifically identifies early-onset ARDS as a complication of freshwater submersion 2. The case described in the research evidence demonstrates difficulties in oxygenation and ventilation encountered shortly after resuscitation from freshwater submersion, which is consistent with the development of ARDS.

Why ARDS Over Other Options

Let's examine why ARDS is more likely than the other options:

• Bacterial pneumonia (Option C) - While common after drowning, typically develops after 48-72 hours, not within the first 36 hours 3
• Bacteremia (Option B) - Uncommon as an early complication; more likely to occur later if pneumonia develops
• Hypernatremia (Option D) - More associated with saltwater drowning, not freshwater
• Metabolic alkalosis (Option E) - Not typically seen; freshwater drowning more commonly leads to metabolic acidosis initially

Management Considerations

For a patient with near-drowning who has been resuscitated:

• Close monitoring of respiratory status with serial arterial blood gases
• Supplemental oxygen to maintain adequate saturation
• Early consideration of positive pressure ventilation (CPAP/PEEP) if respiratory distress develops
• Lung-protective ventilation strategies if intubation becomes necessary
• Avoid prophylactic antibiotics unless signs of infection develop 4

Important Caveats

1. The severity of ARDS can vary widely - from mild hypoxemia to severe respiratory failure requiring mechanical ventilation
2. Even patients who initially appear to recover may deteriorate within hours due to progressive lung injury
3. Improvement of lung injury is typically rapid in most cases, with resolution of hypoxemia observed in approximately 77% of cases by day 4 3
4. Neurological outcomes should be closely monitored as cerebral injury is another crucial consequence of the hypoxemia resulting from near-drowning 4

Early recognition and appropriate respiratory support are essential in managing this potentially life-threatening complication of near-drowning.