From the Guidelines
PEEP is beneficial in several respiratory pathologies, including acute respiratory distress syndrome (ARDS), where it prevents alveolar collapse, improves oxygenation, and reduces ventilator-induced lung injury, as evidenced by a study published in the American Journal of Respiratory and Critical Care Medicine in 2017 1.
Pathologies Benefiting from PEEP
- Acute Respiratory Distress Syndrome (ARDS): PEEP helps prevent alveolar collapse, improves oxygenation, and reduces ventilator-induced lung injury, with higher PEEP levels (12-15 cmH2O or more) often required 1.
- Cardiogenic Pulmonary Edema: PEEP reduces preload and afterload while improving lung compliance.
- Obstructive Sleep Apnea: PEEP (delivered as CPAP) maintains airway patency during sleep.
- Atelectasis: PEEP keeps alveoli open, improving ventilation-perfusion matching.
- Pneumonia: PEEP helps recruit collapsed alveoli affected by inflammation and exudate.
Mechanism of Action
PEEP works by maintaining positive pressure in the airways throughout the respiratory cycle, preventing alveolar collapse, improving lung compliance, and enhancing gas exchange by recruiting previously collapsed alveoli.
Typical PEEP Settings
Typical PEEP settings range from 5-20 cmH2O depending on the condition, with ARDS often requiring higher levels (12-15 cmH2O or more) while less severe conditions may need only 5-8 cmH2O.
Considerations in Specific Conditions
In patients with aneurysmal subarachnoid hemorrhage (aSAH), the use of PEEP should be carefully considered, as high PEEP levels may be associated with increased intracranial pressure (ICP) and decreased cerebral perfusion pressure (CPP), as reported in a study published in Critical Care in 2020 1. However, the benefits of PEEP in improving oxygenation and reducing ventilator-induced lung injury should also be taken into account, and the decision to use PEEP should be made on a case-by-case basis, considering the individual patient's condition and response to treatment.
From the Research
Pathologies Where PEEP is Beneficial
- Acute Respiratory Distress Syndrome (ARDS): PEEP has been shown to improve oxygenation and reduce mortality in ARDS patients, particularly those who respond to increased PEEP with improved oxygenation 2.
- Acute Lung Injury (ALI): High PEEP levels may improve survival in ALI patients, especially those with greater overall severity of illness 3.
Mechanisms of PEEP
- Recruitment of collapsed alveoli: PEEP helps to recruit collapsed alveoli, improving oxygenation and reducing intrapulmonary shunt 4, 5.
- Prevention of alveolar collapse: PEEP prevents alveolar collapse at end expiration, promoting more homogenous ventilation 5.
- Reduction of tidal lung stress and strain: Higher PEEP can reduce tidal lung stress and strain, potentially reducing ventilator-induced lung injury 5.
Patient-Specific Considerations
- Individualized PEEP titration: Some patients may require highly individualized PEEP titration based on their respiratory system mechanics and response to PEEP 4, 5.
- Patients with severe lung injury and/or abnormal chest-wall compliance: These patients may require alternative PEEP titration strategies, such as using a recruitment maneuver and a PEEP decrement trial 4.