Question
A 76-year-old woman comes to the physician for a routine examination. She has a history of hypertension well controlled with diet and exercise. She has no history of smoking or illicit drug use. She walks one mile daily. Her pulse is 68/min, respirations are 16/min, and blood pressure is 119/76 mm Hg. Physical examination shows no abnormalities. Which of the following age-related changes in respiratory function is most likely present in this patient?
| A. |
Increased lung compliance
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| B. |
Increased vital capacity
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| C. |
Decreased residual volume
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| D. |
Decreased total lung capacity
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Show Answer
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Correct Answer � A
Explanation
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Answer A. Increased lung compliance
The patient lacks any history of respiratory disease and has a normal physical examination. Therefore, her change in respiratory function is likely a consequence of normal aging.
Increased lung compliance
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Increased lung compliance is commonly found in individuals of advanced age due to loss of elastic fibers.
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Chest wall compliance typically decreases because of increased chest wall stiffness.
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Stiffening of the chest wall and loss of elastic recoil impair lung emptying during expiration, which increases residual volume. When compared to a healthy young adult, individuals of advanced age have increased alveolar dead space and increased V/Q mismatch due to age-related loss of lung surface area.
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Moreover, while FEV1 and vital capacity classically decrease with age, total lung capacity usually remains unchanged.
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Other age-related changes include decreased respiratory muscle strength (which can hinder effective coughing and increase the risk of aspiration and infection) and impaired ventilatory response to hypercapnia and hypoxia.
Increased vital capacity
Decreased residual volume
Decreased total lung capacity
- Decreased total lung capacity (TLC = vital capacity + residual volume) is classically seen in patients with restrictive lung disease. While normal aging is associated with an overall decrease in lung function, TLC will remain constant in the absence of respiratory disease.
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