Normal PEEP Settings
In mechanically ventilated patients without specific lung pathology, PEEP is typically set at 5 cmH₂O, which represents the standard baseline setting to maintain physiologic functional residual capacity and prevent alveolar collapse. 1, 2
Standard PEEP Ranges by Clinical Context
Patients Without Lung Injury
- Baseline PEEP of 5 cmH₂O is the conventional starting point for mechanically ventilated patients with normal lungs or minimal pathology 1, 2
- This level helps maintain alveolar patency and prevents atelectasis without causing significant hemodynamic compromise 1
- At 5 cmH₂O PEEP, end-expiratory lung volume in patients with normal lungs averages 31 ml/kg predicted body weight, which is approximately 66% of predicted sitting functional residual capacity 3
Patients With Obstructive Disease (COPD/Asthma)
- External PEEP of 5 cmH₂O or less is typically used, even when auto-PEEP (intrinsic PEEP) is higher 2
- The British Thoracic Society recommends PEEP in the range of 5-10 cmH₂O for patients with neuromuscular disease or chest wall deformity to increase residual volume and reduce oxygen dependency 1
- External PEEP should be applied at approximately 50-85% of measured auto-PEEP to counterbalance the inspiratory threshold load without worsening hyperinflation 4
- Never set external PEEP levels in excess of intrinsic PEEP, as this worsens hyperinflation and can cause hemodynamic compromise 2, 4
Patients With ARDS
- Higher PEEP levels (typically 10-15 cmH₂O or more) are used in moderate to severe ARDS (PaO₂/FiO₂ ≤ 200 mmHg), as meta-analyses show mortality reduction with higher PEEP in this population 1
- PEEP should be individualized using methods such as the electrical impedance tomography overdistension-collapse method, which identifies the PEEP that jointly minimizes both collapse and overdistension 1
- A standardized PEEP window from 24 to 6 cmH₂O during decremental PEEP trials improves reliability for PEEP titration in ARDS 1
Critical Monitoring Parameters
Plateau Pressure Limits
- For patients without ARDS, maintain plateau pressures below 25 cmH₂O 4
- For ARDS patients, plateau pressures should remain below 30 cmH₂O to prevent ventilator-induced lung injury 4
- These limits guide the maximum acceptable PEEP when combined with tidal volume settings 4
Hemodynamic Considerations
- High PEEP levels can decrease cardiac output by increasing intrathoracic pressure and reducing venous return 1, 4
- In patients with right ventricular dysfunction or pulmonary hypertension, lower PEEP levels may be preferable to minimize adverse effects on pulmonary blood flow 4
- Careful cardiovascular monitoring is essential when implementing PEEP, particularly in cardiac patients 4
Common Pitfalls to Avoid
Auto-PEEP Management
- Always measure auto-PEEP before applying external PEEP using the end-expiratory occlusion technique, which requires the patient to be passive 2, 4
- Applying external PEEP blindly without measuring auto-PEEP first can lead to excessive total PEEP and worsen hyperinflation 4
- In patients with auto-PEEP, use flow triggering instead of pressure triggering, as pressure triggers worsen patient-ventilator asynchrony and increase work of breathing 2
Ventilator Mode Considerations
- PEEP titration using the overdistension-collapse method requires volume-controlled ventilation with inspiratory pause >0.5 seconds and no intrinsic PEEP, or pressure-controlled mode with sufficient equilibration time 1
- Auto-PEEP measurement may not be possible during assisted ventilation modes (PSV, BIPAP) on some ventilators 5