What does PEFR measure in respiratory assessments?

Peak Expiratory Flow Rate (PEFR) specifically measures the maximum speed of expiration, indicating how quickly a person can exhale air from their lungs. This measurement is essential for assessing airflow limitation in conditions like asthma and chronic obstructive pulmonary disease (COPD). By determining the peak flow, healthcare providers can evaluate the severity of airway obstruction, monitor changes in a patient's respiratory status over time, and decide on the efficacy of treatments or interventions.

In contrast, measures like the total lung capacity provide insight into the overall volume of air the lungs can hold, which is not the focus of PEFR. The volume of air in the lungs at rest and the effectiveness of inhaled medications pertain to different aspects of lung function and treatment outcomes but do not relate directly to the peak flow measurement. Thus, the correct understanding of PEFR’s role in respiratory assessments highlights its function in providing a quick and valuable indicator of a patient's ability to expel air forcefully and efficiently.