A peak flow meter measures which of the following in asthma?

A peak flow meter measures which of the following in asthma?

• A. Tidal volume
• B. Airflow out of the lungs
• C. Oxygen saturation
• D. Residual volume

Answer: (B)

Peak flow meters measure how fast air can be blown out of the lungs, i.e., the peak expiratory flow rate. In asthma, airway inflammation and bronchoconstriction narrow the airways, so the speed of exhalation decreases. Tracking this flow helps you gauge asthma control, detect early worsening, and guide treatment decisions using personal best values and zone guidelines. Tidal volume, the normal amount of air per breath, is measured by spirometry, not a peak flow meter. Oxygen saturation reflects how much oxygen is carried in the blood and is read with a pulse oximeter. Residual volume is the air remaining after a full exhale and requires specialized testing. So the peak flow meter specifically assesses airflow out of the lungs.

Peak flow meters measure how fast air can be blown out of the lungs, i.e., the peak expiratory flow rate. In asthma, airway inflammation and bronchoconstriction narrow the airways, so the speed of exhalation decreases. Tracking this flow helps you gauge asthma control, detect early worsening, and guide treatment decisions using personal best values and zone guidelines. Tidal volume, the normal amount of air per breath, is measured by spirometry, not a peak flow meter. Oxygen saturation reflects how much oxygen is carried in the blood and is read with a pulse oximeter. Residual volume is the air remaining after a full exhale and requires specialized testing. So the peak flow meter specifically assesses airflow out of the lungs.