An individual with respiratory symptoms undergoes pulmonary function testing.The RV measured by helium dilution is increased but is lower than the RV measured by body plethysmography.Which of the following is the most likely explanation for this difference?
A)There is a problem with one of the machines.
B)The individual has severe air trapping.
C)The individual did not keep his mouth pressed tightly around the mouthpiece,and air leaked out during the helium dilution testing.
D)The individual held his breath during body plethysmography.
E)The individual has a loss of lung compliance.

Question

Quizplus · Accepted Answer

The increased RV measured by body plethysmography suggests severe air trapping, which could explain the difference between the RV measured by helium dilution and body plethysmography. Option A is less likely as it is less probable that there is an issue with both machines. Option C is possible but the difference is unlikely to be significant. Option D is less probable unless the instructions were misunderstood. Option E is less likely, as loss of compliance is associated with lower lung volume.

An Individual with Respiratory Symptoms Undergoes Pulmonary Function Testing