How do I manage elevated plateau pressure in a patient with acute respiratory distress syndrome (ARDS) on mechanical ventilation?

Managing Elevated Plateau Pressure in ARDS

Immediately reduce tidal volume below 6 mL/kg predicted body weight if plateau pressure exceeds 30 cm H₂O, as maintaining plateau pressure ≤30 cm H₂O is an absolute ceiling that takes priority over tidal volume targets. 1, 2, 3

Primary Intervention: Tidal Volume Reduction

• Decrease tidal volume incrementally (even below the standard 4-6 mL/kg PBW range) until plateau pressure falls to ≤30 cm H₂O 1, 3
• Calculate predicted body weight accurately: PBW (men) = 50 + 0.91 × (height in cm - 152.4) kg; PBW (women) = 45.5 + 0.91 × (height in cm - 152.4) kg 2
• Accept permissive hypercapnia as a necessary consequence of lower tidal volumes to prevent ventilator-induced lung injury from alveolar overdistension 3

Secondary Target: Optimize Driving Pressure

• Calculate driving pressure (ΔP = plateau pressure - PEEP) and target ≤15 cm H₂O, as this predicts mortality better than plateau pressure or tidal volume alone 4, 5
• If driving pressure exceeds 15 cm H₂O despite achieving plateau pressure ≤30 cm H₂O, further intervention is required 4
• Driving pressure ≥18 cm H₂O specifically increases risk of right ventricular failure and should be avoided 3, 4

PEEP Optimization Strategy

• Increase PEEP to recruit collapsed alveoli and improve respiratory system compliance, which simultaneously lowers driving pressure 4
• For moderate-severe ARDS (PaO₂/FiO₂ ≤200 mmHg), use higher PEEP strategies (conditional recommendation), as this reduces mortality (adjusted RR 0.90) 1, 3, 4
• Consider esophageal manometry to guide PEEP titration by measuring transpulmonary pressure, which accounts for chest wall mechanics that vary unpredictably between patients 6, 7
• Esophageal pressure measurements reveal that only 24% of variance in transpulmonary pressure is explained by airway pressure, with 52% due to pleural pressure variation 7

Advanced Monitoring Considerations

• Measure plateau pressure accurately during an inspiratory hold maneuver with adequate sedation/paralysis 4, 7
• Use volume-controlled ventilation during the acute phase of ARDS because it enables precise monitoring of plateau pressure and driving pressure 3
• In decelerating-flow modes (pressure-regulated volume control), peak inspiratory pressure approximates plateau pressure within 1-2 cm H₂O when inspiratory flow reaches zero, but verify this assumption 8
• Elevated esophageal pressures (averaging 17.5 ± 5.7 cm H₂O at end-expiration in acute respiratory failure) indicate that chest wall properties contribute substantially to total respiratory impedance 7

Adjunctive Therapies for Refractory Cases

When plateau pressure remains elevated despite tidal volume reduction and PEEP optimization:

• Prone positioning >12 hours/day for severe ARDS (strong recommendation), which reduces mortality (RR 0.74) 1, 4, 9
• Consider neuromuscular blockade for ≤48 hours when PaO₂/FiO₂ <150 mmHg (weak recommendation) 3, 9
• Recruitment maneuvers may be attempted in moderate-severe ARDS with refractory hypoxemia (conditional recommendation, low confidence) 1, 3
• Conservative fluid management strategy for established ARDS without tissue hypoperfusion (strong recommendation) 3, 9

Escalation to Rescue Therapies

• Consider ECMO for critically ill patients with severe hypoxemia (PaO₂/FiO₂ <100 mmHg) despite optimized PEEP, neuromuscular blockade, and prone ventilation 2, 4, 9
• ECMO allows for "lung rest" by enabling further reduction in tidal volumes and plateau pressures while maintaining adequate gas exchange 9
• Salvage modes (high-frequency oscillatory ventilation, airway pressure release ventilation) may be considered in select refractory cases, though high-frequency oscillatory ventilation is strongly recommended against for routine use 1, 9

Critical Pitfalls to Avoid

• Never prioritize oxygenation targets over plateau pressure limits - accepting higher plateau pressures to improve oxygenation increases mortality through ventilator-induced lung injury 1, 3
• Do not assume airway pressure accurately reflects transpulmonary pressure without considering chest wall mechanics, particularly in obese patients or those with abdominal distension 6, 7
• Avoid using pressure-controlled ventilation during the acute phase when precise plateau pressure monitoring is critical, as it does not guarantee fixed tidal volumes and can lead to inadvertent excessive volumes if compliance improves 3
• Recognize that mean airway pressure increases not only with PEEP but also with longer duty cycles and higher driving pressures, all of which can impair right ventricular function and venous return 1