A 40-year-old woman with a recent onset of asthma is receiving education regarding her newly prescribed medications. Which of the following will most likely cause her to experience hoarseness?

Prior to performing a multiple-breath U2 washout test, a pulmonary function technologist is unable to zero the H2 gas analyzer. Which of the following may be responsible?

While performing a quality control test on an open circuit nitrogen system, the volume of a 3-liter syringe is measured as 3.9 L. Which of the following is the most probable explanation?

Successive peak flow measurements made with a peak flowmeter on a subject previously diagnosed as having asthma yield the following results:

Which of the following is the best explanation for these?