Question

What is the significance of a PEFR (peak expiratory flow rate) at 60% predicted, and if spirometry were performed at this time, what would be the likely findings? (select all that apply)

A. A value of 60% is considered a persistent moderate classification of severity.
B. Predicted value is an average PEFR value based on the PEFR values of a larger population grouped by height and age. In asthma patients there is good correlation between PEFR and forced expiratory volume measured by spirometry. Pulmonary function tests would show increased FEV/forced vital capacity, decreased functional residual capacity and decreased residual volume.
C. PEFR is a measure of how fast a person can exhale air. It is one of many tests used to assess airway function. During an asthma attack, airflow during exhalation is decreased by narrowing or blockage of the airways.
D. A rise in PEFR in the presence of clinical manifestations suggests an impending acute attack, requiring early treatment to prevent complications.

Answer 1

A PEFR at 60% predicted indicates moderate airway obstruction, often associated with asthma. Spirometry would show reduced FEV1 and a low FEV1/FVC ratio, pointing to obstructive lung disease. The correct options that apply to a PEFR at 60% predicted are A and C, as they correctly describe the significance and expected spirometric findings.

Step-by-step explanation:

A PEFR (peak expiratory flow rate) at 60% predicted significance is that it is generally indicative of a moderate obstruction in the airways, often seen in conditions like asthma. Spirometry would likely reveal impaired lung function, including a decreased FEV1 (forced expiratory volume in one second), decreased FEV1/FVC (forced vital capacity) ratio, and possibly decreased functional residual capacity (FRC) and residual volume. Since PEFR is a measurement of the maximum speed of expiration, a low value (like 60% of the predicted norm) signifies that air is being exhaled from the lungs at a slower rate than would be expected for an individual's age, sex, and height. This suggests that there is some level of obstruction.

Spirometry, if performed, would typically show a reduced FEV1 as less air is expelled in the first second of a forceful exhale due to the narrowed airways. The FEV1/FVC ratio would also be low when compared to normal values, as airflow obstruction characteristic of obstructive lung disease (such as asthma) makes it difficult to quickly expel air.

Therefore, the correct options that apply to a PEFR at 60% predicted are:

• A value of 60% is considered a persistent moderate classification of severity.
• Predicted value is an average PEFR based on larger population groupings, and there is a good correlation between PEFR and FEV in asthma patients. Spirometry would likely show decreased FEV1/FVC ratio, but not necessarily increased FEV/FVC ratio or decreased functional residual capacity and residual volume.
• PEFR is a measure of how fast a person can exhale air and is used to assess airway function. During an asthma attack, exhalation is decreased due to narrowing or blockage of the airways.