What does a peak flow meter measure?

A peak flow meter measures the maximum speed of expiration, which is a vital indicator of how well air is being expelled from the lungs. By determining the peak expiratory flow rate (PEFR), healthcare providers can assess the patient's lung function and the degree of obstruction in the airways. This measurement is particularly useful for patients with asthma or chronic obstructive pulmonary disease (COPD), as it helps monitor their condition and response to treatment.

The device works by allowing the patient to take a deep breath and then exhale forcefully into the peak flow meter. The reading obtained reflects the highest flow rate achieved during the forced expiration, thereby offering valuable information about airway patency and respiratory status. Monitoring changes in this value over time can help identify exacerbations or deteriorations in lung function, guiding appropriate management strategies.