Pulmonary Function Testing Flashcards

The peak expiratory flow (PEF) is most effort-dependent and primarily reflects:

Answer: Large central airway caliber and effort

PEF is highly effort-dependent and reflects large central airway function; it is commonly used for asthma monitoring but is not a sensitive marker of small airway disease.

FEF25-75% (mid-expiratory flow rate) is considered a sensitive marker for:

Answer: Small airway disease (early COPD)

FEF25-75% reflects flow rates in the mid-portion of the FVC maneuver, which is less effort-dependent and more sensitive to small airway obstruction.

An adult patient has a TLC of 120% predicted, an FRC of 140% predicted, and a reduced FEV1/FVC ratio. These findings are consistent with:

Answer: Severe emphysema with air trapping

Elevated TLC, markedly elevated FRC (hyperinflation), and reduced FEV1/FVC ratio are classic features of severe emphysema with gas trapping.

Which spirometric pattern is typically seen in a patient with severe scoliosis?

Answer: Restrictive pattern

Severe scoliosis restricts chest wall expansion, reducing lung volumes and producing a restrictive spirometric pattern with reduced FVC and TLC.

During methacholine challenge testing, a positive result (PC20) is defined as a ≥20% fall in FEV1 at a concentration of methacholine at or below:

Answer: 8 mg/mL

A PC20 ≤8 mg/mL is the traditional threshold for a positive methacholine challenge, indicating airway hyperresponsiveness consistent with asthma.

Respiratory muscle strength is assessed by measuring:

Answer: Maximum inspiratory pressure (MIP/PImax) and maximum expiratory pressure (MEP/PEmax)

MIP and MEP directly measure the force-generating capacity of inspiratory and expiratory muscles, respectively, to evaluate neuromuscular respiratory disease.