Peak expiratory flow measures what?

Peak expiratory flow measures what?

• A. Airflow into the lungs.
• B. Lung volumes.
• C. Diffusion capacity of the alveoli.
• D. Airflow out of the lungs.

Answer: (D)

Peak expiratory flow rate measures the maximum speed at which air can be exhaled after a full inhalation. It reflects how open the large airways are and how much obstruction is present. This measurement is widely used in asthma management to monitor control and detect early signs of worsening airway constriction; comparing current readings to a personal best helps categorize the level of control and needs for treatment adjustments. It does not assess airflow into the lungs (inspiratory flow), nor does it measure total lung volumes (like FVC, TLC, or residual volume), nor diffusion capacity across the alveolar membrane (DLCO).

Peak expiratory flow rate measures the maximum speed at which air can be exhaled after a full inhalation. It reflects how open the large airways are and how much obstruction is present. This measurement is widely used in asthma management to monitor control and detect early signs of worsening airway constriction; comparing current readings to a personal best helps categorize the level of control and needs for treatment adjustments. It does not assess airflow into the lungs (inspiratory flow), nor does it measure total lung volumes (like FVC, TLC, or residual volume), nor diffusion capacity across the alveolar membrane (DLCO).