Increases in airway resistance (Raw) or compliance (CL) affect time constants how?

• A. Fast Time Constants
• B. Slow Time Constants
• C. Short Inspiratory Time
• D. Long Inspiratory Time

Answer: (B)

Time constants describe how quickly the lungs respond to pressure changes during ventilation. The time constant is the product of airway resistance (Raw) and compliance (CL). When either Raw or CL increases, that product grows, so the lungs take longer to reach a given fraction of their final volume. In other words, the system responds more slowly, producing a slow time constant. The other options imply either a faster response or relate to how long you choose to ventilate, not to the intrinsic rate at which the lung fills or empties with changes in Raw or CL.