Since its introduction in 1959, the peak flowmeter has played an important role in the management of asthma. It is the most useful device available to monitor asthma treatment at home. Routinely used medical instruments should be accurate and over time should be able to produce consistent results.
For this report, we evaluated the accuracy of three commonly used, inexpensive, hand-held peak flowmeters. The performance of these peak flowmeters was then reevaluated after being used 200 times. In the treatment and monitoring of asthma, accuracy in the ranges below 300 L/min can be considered most important. It is in this range that decisions regarding short- and long-term therapies will be made. At flows higher than this, the patient will most likely be well. The Assess peak flowmeter outperformed the MiniWright peak flowmeter at peak flows less than 300 L/min. With use, the accuracy of the MiniWright peak flowmeter diminished while that of the Assess peak flowmeter remained relatively unchanged. Peak flow measurements are also used to follow trends over the course of weeks or longer. Therefore, for an individual using the same meter at all times, absolute accuracy may not always be necessary. However, it is important to allow valid comparison with office or hospital equipment.