Peak Flow Meters
A peak flow meter is a handheld device that measures the volume of air that you can forcibly exhale from your airways. This volume is referred to as your peak expiratory flow rate or PEFR. PEFR is the measurement from the peak flow meter after you take the deepest breath possible and blow into the meter with a single, forceful blast.
PEFR indicates one aspect of airway obstruction, and is an inexpensive way to monitor your lung function at home. Measuring your PEFR can be very helpful in detecting changes in airway function, which can signal a potential asthma attack. Your PEFR will improve as your symptoms are better controlled. Your target PEFR is the number you should be able to achieve when your asthma is under control.