If a ventilated patient has a plateau pressure of 42 cm H2O during an inspiratory hold, what is the first adjustment you should make?

• A. Decrease the tidal volume
• B. Decrease the rate
• C. Increase the rate
• D. Increase the tidal volume

Answer: (A)

High plateau pressure signals the lungs are being overdistended during inspiration, increasing the risk of volutrauma. The first adjustment is to lower the tidal volume because reducing the amount of air delivered per breath directly decreases the alveolar distending pressure measured as plateau pressure. The goal is to bring plateau pressure down toward a safe range (typically below 30 cm H2O) while preserving adequate ventilation. In practice, you’d reduce tidal volume (often toward around 6 mL/kg predicted body weight for ARDS or lung-protective settings) and then reassess. If ventilation becomes insufficient, you can adjust the rate or other settings after ensuring the plateau pressure is within a safe range. Increasing tidal volume would worsen the plateau pressure, and increasing the rate won’t directly address the overdistension and can cause other issues, so those are not first steps.