Which of the following best describes the term 'total lung volume' (TLV) in restrictive lung disease?

• A. Greater than predicted values
• B. Less than predicted values
• C. Normal compared to predicted values
• D. Fluctuating based on conditions

Answer: (B)

Total lung volume (TLV) in restrictive lung disease is best described as being less than predicted values. In restrictive lung diseases, there is a decrease in lung volumes due to reduced expansion of the lung parenchyma. This reduction is typically seen in conditions such as pulmonary fibrosis, pulmonary edema, and certain neuromuscular disorders, which all hinder effective respiration and lead to a limitation in the total amount of air that can be inhaled.

As lung compliance decreases, the lungs become stiffer and less capable of expanding fully during inhalation. Consequently, when performing pulmonary function tests, measurements of lung volumes will typically show a total lung capacity (TLC) that is below the predicted values for an individual based on factors such as age, sex, height, and ethnicity.

Understanding this aspect of restrictive lung disease is essential for diagnosing and managing these conditions, as treatment often focuses on addressing the underlying cause of the restriction and improving the patient's respiratory function.