The use of PEEP is generally recommended when a patient's PaO2 is < 60 mmHg on an FIO2 of > 0.50, indicating severe issues with oxygenation.
The recommended starting point for considering the use of Positive End-Expiratory Pressure (PEEP) in respiratory care is typically when a patient has a partial pressure of oxygen (PaO2) of < 60 mmHg on a fractional inspired oxygen (FIO2) of > 0.50. This situation suggests that the patient is experiencing significant difficulties with oxygenation, and PEEP may help to increase oxygenation by preventing alveolar collapse at the end of expiration.