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PEF Monitoring in asthma PDF Print E-mail
Written by Leong Oon Keong   
Sunday, 02 September 2012 13:24

Peak Expiratory Flow (PEF) is measured using a peak flow meter which is inexpensive.

PEF monitoring can be used to diagnose and monitor asthma.  However, spirometry is the method of choice for measuring airflow limitation and reversibility to establish a diagnosis of asthma. 

PEf measurements should preferably be compared to the previous best measuemnts using one's own peak flow meter.  The previous best measurement is usually obtained when the person is asymptomatic or on full treatment. The personal best PEF serves as a reference value for monitoring the effects of changes in treatment.

PEF measurements are usually taken first thing in the morning before treatment is taken when the value is usually the lowest and the last thing at night when values are usually higher in asthma.

PEF measurements are useful in the following ways:-

1.  To confirm the diagnosis of asthma.  A 60 L/min increase or a 20% improvement in PEF post bronchodilator treatment is suggestive of asthma.  Similarly a diurnal variation of PEF of more than 20% is also suggestive of asthma. 

2.  To improve control of asthma, particularly in patients with poor perception of symptoms.  Self monitoring of symptoms and PEF charting are included in asthma management plans.

3.  To identify exercise induced asthma or environmental causes of asthma symptoms.  The person monitors PEF before and afer exercise or several times each day over periods of suspected exposure to risk factors in the home or workplace.

Lung function testing by PEF or spirometry continues to be recommended as an aid to the diagnosis and monitoring of ashtma control.  Measuring the variability of airflow limitation is key to both asthma diagnosis and the assessment of asthma control.

Last Updated on Sunday, 16 September 2012 04:10