PULMONARY

Aspiration of both seawater and freshwater in relatively small quantities can lead to disruptions in the surfactant equilibrium of the lungs. Reduced surfactant leads to atelectasis which can make patients more prone to atelectrauma and subsequent biotrauma (neutrophil migration and subsequent acute respiratory distress syndrome or sepsis).36,38 Osmotic shifts in the alveoli can lead to noncardiogenic pulmonary edema which results in reduced compliance, right to left shunting, and hypoxemia. Evidence-based care for mechanically ventilated patients should be followed. 2

- Maintain saturation at 92% (or PaO2 between 55-80mmhg) while avoiding hyperoxia.
- Oxygenation should be maintained by titrating fraction of inspired O2 (FIO2) and incremental increases in PEEP, which will help to reduce incidence of barotrauma. Current literature suggests achieving a PaO2>FIO2 ratio of >250.
- Once adequate oxygenation has been achieved, the same PEEP should be maintained for 48 hours without attempts to wean from the ventilator.
- The best available evidence indicates pulmonary surfactant restores in 48 hours. Early attempts at extubation may lead to recurrent pulmonary edema and increased ventilator days.
- Avoid permissive hypercapnia (unless neurologic status is intact) due to concern for concomitant neurologic injury that may worsen with high pCO2.
- A lung protective ventilator strategy should be followed with the goal of preventing barotrauma.
  - Maintain tidal volumes of 6cc/kg of predicted body weight.
  - PEEP strategy as noted above.
  - Maintain plateau pressures < 30 cmH20, Driving pressure <15 cmH20.
  - Consider bronchoscopy for quantitative cultures and foreign body removal if there is concern for aspiration (e.g., sand, seaweed).
  - Patients with prolonged, severe, or refractory hypoxemia should be considered for ECMO; however, drowning patients were not specifically included in landmark ECMO trials (e.g., EOLIA, CESAR). Case reports of ECMO use in profoundly hypothermic patients have demonstrated some success.
- No role for artificial surfactant.