A pulmonary function technologist is asked to select gas concentrations to simulate pediatric patients' exhaled concentrations during a DLco simulation. Which of the following FECO concentrations should the technologist select?

The following results are obtained:

The RV/TLC ratio from these data is consistent with which of the following?

Which of the following tracings represents an airways resistance maneuver performed with a slow breathing frequency?

Which of the following thresholds for a clinically significant change in lung function from the beginning to the end of a methacholine challenge test is significant?

The following arterial blood gas results are obtained during the final workload of a cardiopulmonary exercise test:

Which of the following best explains these results?