A peak-flow meter is a tool that you and your child can use to help assess the degree of asthma control at any given time. Even though some might erroneously view self-monitoring as a “bother” or a “nuisance,” it should be neither. Regular home peak-flow monitoring has been shown to improve a child’s asthma control, reduce exacerbations, and decrease school absences. Using a peak-flow monitor may also increase your child’s confidence as it will help him or her learn how to optimize asthma control and achieve greater mastery over his or her asthma. Most children can accurately measure their peak flow under adult guidance starting at about 6 years of age. Measurement of peak flow is an assessment of lung function, more precisely, of airflow through larger airways. Peak-flow monitoring also allows for objective decisions about modifying your child’s asthma regimen if appropriate, based on information contained in the written asthma action plan your physician has provided.
When your child is given a prescription for home peak-flow monitoring, you will be asked to determine his or her “personal best” value based on measurements obtained when your child feels well and is symptom-free. An asthma action plan provides instructions on what asthma medication to take as the peak-flow value falls into one of three zones labeled “green,” “yellow,” or “red.” The green zone includes peak-flow measurements in the range of 80% to 100% of a child’s personal best. Yellow corresponds to peak-flow measurements in the range of 60% to 80% of the personal best value. The red zone includes all peak flow values below 60% of a child’s personal best. Peak-flow measurements in the red zone indicate that the child’s asthma is poorly controlled, and that you will need to either contact your physician, proceed to the emergency room, or both. So, if your 10-year-old child with asthma is scheduled to play in a soccer match on Saturday morning and he wakes up feeling apprehensive about the important game, how will a peak-flow measurement be of help?
Suppose you obtain three peak-flow measurements and see that all three values are well into the green zone. These, in fact, approximate the “personal best.” You know that your child’s asthma continues to be well-controlled, and that your young athlete can continue his or her asthma regimen without modification. Pre-game jitters are one thing, and loss of asthma control is another. The reassuring peak-flow values let you address the former without raising your concern about asthma.