In which of the following patients would an end-tidal CO2 most likely produce values that are inconsistent with PaCO2?

During a cardiopulmonary stress test using breath-by-breath gas analysis, a pulmonary function technologist notices that the VO2 suddenly decreases. Which of the following may explain this change?
1. The patient has achieved anaerobic threshold.
2. The measurement of the expired gas volumes is inaccurate.
3. O2 analyzer "phase delay" has increased.
4. There is a leak in the tubing or mouthpiece.

The following data are obtained after an exercise (stress) test for exercise-induced asthma:

Based on these data, the post-exercise FEVi represents a decrease of approximately

To check the reliability of a pulse oximeter reading, a pulmonary function technologist should

Which of the following problems may be identified by using an isothermal lung analog to perform quality control on a body plethysmograph?
1. Improperly calibrated mouth pressure transducer
2. Obstructed or perforated pneumotachometer
3. Increase in mechanical resistance
4. Malfunctioning box pressure transducer