Which statement correctly describes EPAP function on BiPAP?

Which statement correctly describes EPAP function on BiPAP?

• A. Inspiration - supporting ventilation
• B. Expiration - supporting oxygenation and PaO2
• C. Inspiration - supporting oxygenation
• D. Expiration - supporting ventilation

Answer: (B)

EPAP is the pressure held during expiration to keep the airways open and prevent alveolar collapse. By maintaining airway patency, more of the lung stays open between breaths, which increases functional residual capacity and improves gas exchange, leading to better oxygenation and higher PaO2. It doesn’t directly drive ventilation or CO2 removal—that role belongs to the inspiratory pressure. So describing EPAP as expiration-related pressure that supports oxygenation and PaO2 best captures its function.

EPAP is the pressure held during expiration to keep the airways open and prevent alveolar collapse. By maintaining airway patency, more of the lung stays open between breaths, which increases functional residual capacity and improves gas exchange, leading to better oxygenation and higher PaO2. It doesn’t directly drive ventilation or CO2 removal—that role belongs to the inspiratory pressure. So describing EPAP as expiration-related pressure that supports oxygenation and PaO2 best captures its function.