What is the best management approach for a patient with severe Acute Respiratory Distress Syndrome (ARDS) secondary to drowning?

Management of Severe ARDS Secondary to Drowning

Implement lung-protective ventilation immediately with tidal volumes of 6 mL/kg predicted body weight, plateau pressures <30 cmH2O, and initiate prone positioning for at least 12-16 hours daily if PaO2/FiO2 ratio is <150 mmHg. 1, 2

Immediate Ventilator Settings

Tidal Volume and Pressure Limits

• Set tidal volume at 6 mL/kg predicted body weight (acceptable range 4-8 mL/kg PBW), calculated as 50 + 0.91 × [height (cm) - 152.4] kg for males and 45.5 + 0.91 × [height (cm) - 152.4] kg for females 3, 2
• Maintain plateau pressure <30 cmH2O at all times—this is a strong recommendation with high-quality evidence 3, 2
• Accept permissive hypercapnia (pH >7.20) as a necessary consequence of lung protection rather than increasing tidal volumes 2

PEEP Strategy

• For severe ARDS (PaO2/FiO2 <150 mmHg), use higher PEEP levels, typically 12-15 cmH2O 1, 2, 4
• Titrate PEEP upward to maintain adequate oxygenation while monitoring for hemodynamic compromise 3
• Higher PEEP prevents alveolar collapse and maintains recruitment in drowning-related ARDS where surfactant dysfunction is prominent 2, 5

Prone Positioning: Critical for Severe ARDS

• Initiate prone positioning within 48 hours if PaO2/FiO2 ratio <150 mmHg 3, 2
• Maintain prone position for at least 12-16 hours per day—this is a strong recommendation with moderate-quality evidence showing mortality reduction (RR 0.74) 2, 5, 6
• Repeat daily sessions until oxygenation improves to PaO2/FiO2 >150 mmHg 5, 4
• Duration matters: trials demonstrating mortality benefit used >12 hours daily, while shorter durations showed no benefit 2

Neuromuscular Blockade

• For severe ARDS with PaO2/FiO2 <150 mmHg, administer neuromuscular blocking agents (cisatracurium) for up to 48 hours 3, 2
• Use early in the course of severe ARDS to improve ventilator synchrony and reduce ventilator-induced lung injury 5, 4
• Administer as intermittent boluses when possible; reserve continuous infusion for persistent ventilator dyssynchrony or when implementing prone positioning 2

Fluid Management

• Apply a conservative fluid strategy once initial resuscitation is complete and tissue perfusion is adequate 3, 2
• Target negative fluid balance using the FACTT-lite protocol—this improves ventilator-free days without increasing non-pulmonary organ failures 2, 5
• This is particularly important in drowning-related ARDS where pulmonary edema is a primary pathophysiologic feature 2

Oxygenation Targets

• Target SpO2 of 88-95% to avoid hyperoxia while maintaining adequate tissue oxygenation 2, 5
• Maintain SpO2 no higher than 96% in acute hypoxemic respiratory failure to prevent oxygen toxicity 2
• Titrate FiO2 downward as tolerated once adequate oxygenation is achieved 1

Corticosteroids

• Administer systemic corticosteroids to mechanically ventilated patients with ARDS—this represents the most recent high-quality recommendation from the American Thoracic Society 2
• This is a conditional recommendation with moderate certainty of evidence 2
• However, avoid high-dose pulse steroids as they do not improve survival and may cause harm 5

Rescue Therapies for Refractory Hypoxemia

Recruitment Maneuvers

• Consider recruitment maneuvers cautiously in severe ARDS, but do not use routinely or for prolonged periods as these are associated with harm 3, 2

ECMO Consideration

• For refractory hypoxemia despite optimized ventilation and prone positioning, consider venovenous ECMO at experienced centers 2, 5, 6
• Specific indications: PaO2/FiO2 <70 mmHg for ≥3 hours or <100 mmHg for ≥6 hours despite optimal management 5
• ECMO should only be performed at centers with established expertise and protocols 2, 5

Interventions to Avoid

• Do not use high-frequency oscillatory ventilation—this is strongly recommended against with moderate-quality evidence 3, 2, 6
• Do not use β-2 agonists for ARDS treatment without bronchospasm 3, 2
• Do not routinely use pulmonary artery catheters for ARDS management 3, 2
• Do not prioritize normocapnia over lung-protective ventilation—accept permissive hypercapnia 2

Supportive Care Measures

• Maintain head of bed elevation at 30-45 degrees to prevent ventilator-associated pneumonia 3, 5
• Implement daily spontaneous breathing trials once patients show signs of improvement 3, 2
• Use a weaning protocol for patients who can tolerate weaning 3
• Provide deep sedation in the first 48 hours, then minimize continuous sedation targeting specific endpoints 2, 5

Critical Pitfalls to Avoid

• Do not delay prone positioning in severe ARDS—early implementation (within 48 hours) improves outcomes 2, 5
• Do not use tidal volumes >8 mL/kg PBW even if plateau pressures are acceptable—both parameters must be optimized simultaneously 2, 7
• Do not apply higher PEEP indiscriminately in mild ARDS or hemodynamically unstable patients—tailor to disease severity 2, 5
• Do not use excessive tidal volumes to correct hypercapnia—this negates the mortality benefit of lung-protective ventilation 3, 8
• Do not maintain fluid-positive balance after initial resuscitation—this worsens pulmonary edema and prolongs mechanical ventilation 2, 5