Final answer:
Positive pressure can be harmful in restrictive lung diseases such as respiratory distress syndrome and pulmonary fibrosis, where it can cause airway collapse during exhalation and trap air in the lungs.
Step-by-step explanation:
An example of a condition in which positive pressure would be harmful is in restrictive lung diseases such as respiratory distress syndrome and pulmonary fibrosis. In these conditions, the airways are less compliant due to stiff or fibrotic lung tissue, which decreases lung compliance and makes exhalation difficult. During exhalation, the intrathoracic pressure becomes more positive which can cause airway collapse, trapping air in the lungs and reducing the FVC (Forced Vital Capacity), thereby limiting the amount of air a person can exhale.
Learn more about Positive Pressure in Restrictive Lung Diseases