During ventilation, what is the target for end-inspiratory transpulmonary pressure to avoid overdistension?

During ventilation, what is the target for end-inspiratory transpulmonary pressure to avoid overdistension?

• A. Less than 25 cmH2O
• B. Greater than 30 cmH2O
• C. Exactly 0 cmH2O
• D. Less than -5 cmH2O

Answer: (A)

The key idea is that end-inspiratory transpulmonary pressure is the actual distending pressure across the lung at the end of inspiration. If this pressure becomes too high, lungs can overdistend, increasing the risk of ventilator-induced lung injury. A commonly used safe ceiling for this pressure is less than about 25 cmH2O, which helps avoid overdistension while still providing adequate inflation. Choosing a value greater than 30 cmH2O would push toward overdistension and higher injury risk, making that option unsuitable. Values around 0 cmH2O or negative pressures at end-inspiration would not provide sufficient distending force to keep the airways open and adequately ventilate the lungs, and a negative value at end-inspiration is physiologically unlikely during active ventilation.

The key idea is that end-inspiratory transpulmonary pressure is the actual distending pressure across the lung at the end of inspiration. If this pressure becomes too high, lungs can overdistend, increasing the risk of ventilator-induced lung injury. A commonly used safe ceiling for this pressure is less than about 25 cmH2O, which helps avoid overdistension while still providing adequate inflation.

Choosing a value greater than 30 cmH2O would push toward overdistension and higher injury risk, making that option unsuitable. Values around 0 cmH2O or negative pressures at end-inspiration would not provide sufficient distending force to keep the airways open and adequately ventilate the lungs, and a negative value at end-inspiration is physiologically unlikely during active ventilation.