During intermittent positive pressure breathing therapy, a patient is breathing at a pressure level of 22 cmH2O at a frequency of 15/min. The neonatal/pediatric specialist notes that the patient is meeting the inspiratory pressure in a shorter time frame than at the beginning of the treatment. This is most likely

• A. An adverse reaction to the therapy
• B. A normal response to therapy
• C. Caused by an inappropriate sensitivity level
• D. A change in the patient's airway resistance

Answer: (D)

The main idea is how airway resistance affects how quickly the patient reaches the set inspiratory pressure during IPPB. If the airway resistance decreases, the same applied pressure drives a greater flow because the airways offer less opposition. That greater flow allows the inspiratory phase to rise to the target pressure more rapidly, so you’d see the patient meeting the inspiratory pressure in a shorter time frame than at the start of therapy. This makes a change in airway resistance the best explanation for the observed pattern.

An adverse reaction would imply a harmful or unexpected effect, which isn’t what this timing change suggests. A normal response could occur, but the specific timing improvement points to a mechanical change in the airways. Inappropriate sensitivity doesn’t fit the scenario either.