A peak flow meter for asthma is a handheld meter that measures how well air flows out of the lungs. Measuring your peak flow using this device is an important part of managing your asthma symptoms and preventing an asthma attack. That is because sometimes you may feel your breathing is fine, but when you measure it with a peak flow meter, you find your lung function is slightly decreased. A PFM can be used to:
• Determine the severity of your asthma
• Check your response to treatment during an acute asthma episode
• Monitor progress in treatment of chronic asthma and provide information for any changes in your therapy
• Detect worsening lung function and avoid a possible serious asthma flare-up
A peak flow meter can help you and your allergist evaluate how severe your asthma is at any point in time. With a peak flow meter, you can often see a drop in your readings even before your symptoms (like coughing or wheezing) get worse. Decreases in peak flow may show that you need to increase your medication. Another measure of asthma control is peak flow variability. For many people with asthma, symptoms are usually worse at night. By consistently monitoring nighttime peak flow measurements, you can tell how well your asthma is controlled. A decrease of 15% or greater from your usual measurement may be a sign of nighttime asthma. A person without asthma or with well-controlled asthma will consistently blow peak flows that vary less than 15%.