What are the systemic effects of immobility on the respiratory system?

• A. Increased risk for atelectasis and hypostatic pneumonia.
• B. Enhanced lung expansion.
• C. Decreased risk of infection.
• D. No respiratory change.

Answer: (A)

Immobility reduces chest wall movement and diaphragmatic excursion, leading to shallower, slower breaths with a smaller tidal volume. When ventilation is insufficient, some alveoli don’t fully inflate and can collapse—atelectasis—especially in the dependent parts of the lungs. Stagnant secretions accumulate because the cough reflex and mucociliary clearance are less effective, creating a favorable environment for bacteria to grow. This combination raises the risk of hypostatic pneumonia, a pneumonia linked to poor drainage of secretions in immobilized patients.

So why this is the best answer: it captures the direct respiratory consequences of immobility—reduced ventilation, atelectasis, and increased infection risk from secretions not being cleared. The alternative idea that mobility enhances lung expansion is incorrect because immobility actually diminishes expansion. The notion of a decreased infection risk is false; immobility increases infection risk due to poor airway clearance. And claiming no respiratory change ignores the clear changes in ventilation and secretion management that accompany immobility.