When is Positive End-Expiratory Pressure (PEEP) recommended for mechanically ventilated patients?

When to Use PEEP in Mechanically Ventilated Patients

PEEP should be applied to all mechanically ventilated patients to prevent alveolar collapse, with a minimum of 5 cm H₂O as the baseline for any patient requiring mechanical ventilation, and higher levels (10-15 cm H₂O) specifically indicated for patients with moderate to severe ARDS (PaO₂/FiO₂ <200 mm Hg). 1, 2

Universal Baseline PEEP Application

• Apply PEEP 5 cm H₂O as the standard minimum for all mechanically ventilated patients to prevent lung derecruitment and atelectasis 1
• Zero PEEP (ZEEP) is explicitly not recommended in any mechanically ventilated patient 1
• This baseline PEEP ameliorates changes in closing volume and prevents cyclic alveolar collapse, often providing dramatic improvements in PaO₂ 1
• The 5 cm H₂O minimum is required for ARDS diagnosis per the Berlin definition 2

PEEP Strategy Based on ARDS Severity

Moderate to Severe ARDS (PaO₂/FiO₂ <200 mm Hg)

• Use higher PEEP levels (typically 10-15 cm H₂O) for patients with moderate to severe ARDS 1, 2
• Individual patient data meta-analysis demonstrated mortality reduction with higher PEEP (mean 15.1 ± 3.6 cm H₂O) versus lower PEEP (mean 9.1 ± 2.7 cm H₂O) specifically in this subgroup 1, 2
• The adjusted relative risk for mortality was 0.90 (95% CI, 0.81-1.00) in moderate/severe ARDS patients receiving higher PEEP 1

Mild ARDS (PaO₂/FiO₂ 200-300 mm Hg)

• Use lower PEEP (<10 cm H₂O) for mild ARDS, as higher PEEP showed no mortality benefit and potential harm in this subgroup 1, 2
• In patients with cirrhosis and mild ARDS, low PEEP strategy is specifically recommended to minimize impairment of venous return and cardiac preload 1

Non-ARDS Patients

• Maintain PEEP 5-8 cm H₂O for patients without ARDS undergoing mechanical ventilation 1
• Physiological data in patients without lung injury suggests 3-5 cm H₂O is appropriate 1

Critical Monitoring Parameters During PEEP Titration

• Always maintain plateau pressure ≤30 cm H₂O regardless of PEEP level 1, 2
• Target driving pressure (plateau pressure minus PEEP) <15 cm H₂O, as this predicts outcomes better than other ventilatory parameters 2
• Monitor for hemodynamic compromise, particularly in patients with baseline vasodilation or sepsis 1, 3
• Avoid excessive PEEP (>15 cm H₂O) that causes lung overdistension and impairs right ventricular function 2

Specific Clinical Scenarios

Sepsis-Related Respiratory Failure

• Apply PEEP to maintain oxygen saturation approximately 88-90% (PaO₂ ~60 mm Hg) with FiO₂ ideally <0.60 1
• PEEP is appropriate and may provide dramatic improvements in PaO₂ in septic patients 1

Intraoperative Mechanical Ventilation

• Set initial PEEP at 5 cm H₂O for all surgical patients; ZEEP is not recommended 1
• Consider higher PEEP with recruitment maneuvers during times when respiratory system compliance changes rapidly (e.g., pneumoperitoneum, steep Trendelenburg positioning) 1

Pediatric Patients

• Use PEEP 3-5 cm H₂O in children without lung injury 1
• Higher PEEP may be needed in severe pediatric ARDS, but careful titration is mandatory to avoid cardiovascular compromise 1
• Be cautious with PEEP levels of 10-12 cm H₂O in children with mild-moderate PARDS, as this significantly increases mechanical power and driving pressure 4

Common Pitfalls to Avoid

• Do not use uniform PEEP for all ARDS patients—severity-based stratification is essential, as mild ARDS patients may be harmed by high PEEP 2
• Do not increase PEEP without monitoring plateau pressure—the 30 cm H₂O plateau pressure limit remains absolute 1, 2
• Do not neglect driving pressure—a low driving pressure (<15 cm H₂O) should guide PEEP optimization alongside oxygenation 2
• Do not assume higher PEEP always improves tissue oxygen delivery—despite improving arterial oxygenation, high PEEP can reduce cardiac output and decrease peripheral oxygen delivery by up to 25% 3
• Do not routinely apply recruitment maneuvers with PEEP—they are conditionally recommended only for moderate/severe ARDS, not as routine therapy 1
• Do not use high-frequency oscillatory ventilation with high baseline PEEP—this approach worsens hemodynamics and increases mortality 1, 2