Residual volumes decrease in which condition?

Residual volumes decrease in which condition?

• A. Restrictive disease
• B. Obstructive disease
• C. Normal
• D. Mixed disease

Answer: (A)

Residual volume is the air left in the lungs after a full forced exhalation. In restrictive disease, the lungs and chest wall are stiff and cannot expand well, causing a reduction in overall lung capacity. Because the lungs are smaller and airways aren’t allowed to empty into a larger capacity, the amount of air left after exhalation (the residual volume) tends to be reduced. In obstructive disease, airway narrowing leads to air trapping, so residual volume increases. Mixed disease often follows the obstructive pattern with higher residual volume as well. Normal would have the usual, unchanged residual volume.

Residual volume is the air left in the lungs after a full forced exhalation. In restrictive disease, the lungs and chest wall are stiff and cannot expand well, causing a reduction in overall lung capacity. Because the lungs are smaller and airways aren’t allowed to empty into a larger capacity, the amount of air left after exhalation (the residual volume) tends to be reduced. In obstructive disease, airway narrowing leads to air trapping, so residual volume increases. Mixed disease often follows the obstructive pattern with higher residual volume as well. Normal would have the usual, unchanged residual volume.