A respiratory therapist should recommend which change for a patient on mechanical ventilation with low PaO2 and mildly elevated PaCO2?

• A. Increase pressure support to 10 cmH2O
• B. Decrease mandatory rate to 4
• C. Increase mandatory rate to 8
• D. Increase set VT to 500 mL

Answer: (A)

Increasing pressure support to 10 cmH2O is a beneficial recommendation for a patient on mechanical ventilation experiencing low PaO2 and mildly elevated PaCO2. Pressure support ventilation assists with the patient's spontaneous breaths by providing a preset level of pressure during inhalation. This increase can improve ventilation by allowing the patient to take deeper breaths, thus enhancing their ability to exchange gases more effectively. A higher pressure support level can also facilitate oxygenation, which is crucial when the PaO2 is low, and it can help eliminate CO2, mitigating the mildly elevated PaCO2.

In contrast, the other options may not adequately address the patient's immediate respiratory needs. Reducing the mandatory rate could lead to further hypoventilation and worsened gas exchange. Increasing the mandatory rate may not provide enough spontaneous breathing support and could cause discomfort or increased work of breathing for the patient. Increasing the set tidal volume (VT) may not be as effective as pressure support, as it doesn’t necessarily improve the patient's effort to breathe while risking overdistension or barotrauma, particularly if the patient has compromised lung mechanics.