Which variable ends expiration and is typically associated with pressure?

• A. Expiration Phase Variable
• B. Inspiration Phase Variables
• C. Breath Triggers
• D. Baseline Variable

Answer: (D)

End-expiratory pressure is the pressure that remains in the airways at the very end of expiration, effectively marking the baseline level of airway pressure when flow is zero. In ventilator terms, that baseline pressure is what ends expiration and is typically set as end-expiratory pressure (PEEP). The Baseline Variable represents this constant pressure level in the circuit, which is why it’s the correct concept here. The other options relate to different phases or triggers of breathing and don’t describe the pressure level that ends expiration.