What does a peak flow meter specifically measure?

A peak flow meter is a device used primarily to measure the maximum speed of expiration, which means it quantifies the rate of airflow in the respiratory system during a forced exhalation. This measurement is particularly valuable for individuals with asthma or other conditions that can cause airflow obstruction. By determining how quickly a person can exhale, healthcare providers can assess the severity of any obstruction present in the airways.

Monitoring peak flow readings allows for the identification of changes in airflow, which can indicate worsening asthma or other respiratory conditions. Therefore, the peak flow meter is an essential tool in evaluating airflow obstruction, making that the most accurate choice for what it specifically measures.

In contrast, while factors like chest expansion, airway resistance, and lung compliance are significant in respiratory assessments, they are not directly measured by a peak flow meter. Instead, they involve different methodologies and equipment for evaluation.