What is a flowmeter?

Flowmetry, also known as spirometry or pulmonary function testing, is a diagnostic procedure used to measure an individual's lung function and airflow parameters. It is a commonly used test in medical, pulmonological and allergological practice to assess respiratory health and diagnose or monitor lung disease.

During a flowmetry, various breathing parameters are measured using a device called a spirometer. The person is asked to inhale deeply and then exhale as quickly and forcefully as possible into the spirometer. The spirometer measures the airflow, volume and velocity of exhaled air, allowing assessment of several parameters, including:

1. Forced Vital Capacity (FVC): This is the maximum amount of air a person can exhale after a maximal inhalation.

2. Forced Expiratory Volume in one second (FEV1): This is the amount of air a person can force exhale in the first second after a maximal inhalation. FEV1 is often used to assess the degree of airflow limitation.

3. Peak Expiratory Flow (PEF): This is the maximum rate at which air is exhaled during a forceful exhalation. PEF can vary depending on airway size and can be used to assess the degree of respiratory limitation.

4. Forced Expiratory Flow (FEF): This is the average airflow rate during a given portion of exhalation. Different FEF values are calculated to evaluate different parts of exhalation, such as FEF25-75%, which measures the average airflow rate between 25% and 75% of exhalation.

Flowmetry is commonly used to diagnose lung conditions such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis, assess disease severity, monitor treatment, and assess the effectiveness of medication or other interventions.

The procedure is usually performed under the supervision of a medical professional, such as a pulmonologist, allergist, or pulmonary function lab technician, and the results are interpreted using reference values and comparisons with expected values for the person's age, sex, and height. It is a safe and non-invasive test that is often performed in clinics, hospitals and other healthcare facilities.