Most experts recommend regular home peak flow monitoring for self-assessment of asthma control because it provides a reliable objective measure of bronchial tube function.
A variety of inexpensive devices are available for home peak flow monitoring and are essential not only for asthma, but may be useful in the management of chronic bronchitis and emphysema. This peak flow meter measures the rate at which you are able to blow air from your lungs and provides an objective assessment of how well a person is breathing. Most devices function satisfactorily up to one to two years. The device should be regularly cleaned with soap and warm water according to the manufacturer’s specifications.
With minimum training, most people can master the technique and keep an accurate record. In both normal and asthmatic patients, the peak flow rate is lower in the early morning hours. However, people with poor asthma control exhibit an excessive variation in peak flow rate throughout the course of the day. There may be an exaggerated morning decrease of peak flow rate, and this is a very sensitive indicator of worsening airway inflammation and poor asthma control.
Simply monitoring the peak flow rate is unlikely to be of any value unless the person has a clear understanding of what to do when this number indicates worsening airflow obstruction. For this purpose, some physicians use three color-coded peak flow rate zones to help management asthma, while others simply require that the person call for help if peak flow rate decreases by 20 percent or more.