During serial ventilator checks, a rise in peak inspiratory pressure with the plateau pressure remaining unchanged most likely indicates which change in the respiratory system?

• A. Increase in tidal volume
• B. Decrease in airway resistance
• C. Increase in PEEP
• D. Increase in airway resistance

Answer: (D)

During ventilation, peak inspiratory pressure reflects both the resistance to flow and the elastic recoil of the lungs and chest (plateau pressure). Plateau pressure is measured when there’s no flow and represents the elastic component. If peak inspiratory pressure rises but plateau pressure stays the same, the change is due to increased airway resistance rather than a change in lung compliance. That means something is hindering flow—like bronchospasm, secretions, or a kinked or blocked tube—causing more pressure to push air in, while the elastic properties of the lungs remain unchanged. Increasing tidal volume or PEEP would typically alter plateau pressure, and decreasing resistance would lower peak pressure, so they don’t fit this pattern.