Peak Flow Rate Measurement

Peak expiratory flow (PEF), a key indicator of lung function, offers clinicians valuable insights into asthma management. Typically measured with a peak flow meter, PEF provides an objective measure of airflow limitation, aiding in assessing asthma control and managing exacerbations (see Image. Peak Flow Meter). A maximal effort is required when using a peak flow meter to obtain valid results. The depth of the preceding breath, airway caliber, muscle strength, and voluntary effort all contribute to PEF. Clinicians should observe patients using a peak flow meter to identify suboptimal effort or technique. However, variability exists between devices, and no good technique exists to calibrate readings between different flow meters. The International Organization for Standardization has published guidelines for PEF meters; clinicians and patients should choose devices that meet these criteria.

Once a patient establishes a personal best, clinicians can create an individualized asthma action plan, including instructions the patient can follow at home. Routine monitoring of a PEF aids in determining the effectiveness of therapy, provides an early warning of potential exacerbations, and can be especially helpful for patients with difficulties recognizing asthma symptoms. PEF measurement can also assess the severity and response to treatment during an acute asthma exacerbation in adolescents and adults. PEF is assessed less commonly during acute exacerbations in younger children. With personalized action plans based on individual PEF values, clinicians can provide early intervention and optimized maintenance therapy, improving management and outcomes for patients with asthma.