Which statement best describes CPAP in contrast to PEEP?

• A. CPAP provides continuous airway pressure during spontaneous breathing, and the patient does all the work; PEEP is a baseline setting in mechanical ventilation that remains after expiration to prevent alveolar collapse.
• B. CPAP uses two pressure levels (IPAP/EPAP); PEEP is not used in CPAP mode.
• C. CPAP is used only during expiration; PEEP is used during inspiration.
• D. CPAP is the same as PEEP in function and use.

Answer: (A)

The main distinction is how CPAP functions in spontaneous breathing versus how PEEP functions on a ventilator. CPAP provides continuous positive airway pressure during spontaneous breathing, and the patient does the work of moving air; there are no mandatory breaths delivered by the machine. PEEP is a baseline positive pressure applied by a ventilator to keep the lungs inflated at end expiration and prevent alveolar collapse, typically used during mechanical ventilation. This contrast—continuous pressure with the patient breathing on their own versus a baseline end-expiratory pressure used in ventilated patients—is what the statement captures.