What could be the cause if a patient on mechanical ventilation has a Peep set but is maintaining a low peak pressure?

• A. Inadequate tidal volume settings
• B. Improperly calibrated pressure monitor
• C. Increased lung compliance
• D. Excess water in ventilator circuit

Answer: (A)

A low peak pressure in a patient on mechanical ventilation with PEEP set could indicate that the ventilator is not delivering enough resistance or that the compliance of the lungs is favorable. When a patient is receiving a low peak pressure despite PEEP settings, this often suggests a situation where the lung compliance is increased, allowing air to flow in more easily, or the tidal volume delivery may not be sufficient to produce higher pressures.

Increased lung compliance indicates that the lungs can expand more easily, which leads to a reduction in pressure needed to ventilate. If the tidal volume is too low, it might not translate to higher peak pressures because the ventilatory efforts are not sufficiently engaging the lung’s capacity. This relationship highlights the importance of adjusting tidal volume settings to match the patient’s needs rather than simply evaluating peak pressures in isolation.

Factors such as having improperly calibrated monitors or excess water in the ventilator circuit could also affect readings, but a direct link between inadequate tidal volume and low peak pressure provides the most plausible explanation in this scenario, emphasizing adequate settings to manage ventilation effectively.