The home peak flow meter is a simple portable device for measuring
a component of lung function. It is not a substitute for the
sophisticated equipment in your physician's office or pulmonary
function laboratory that provides more accurate evaluation of lung
function. However, the peak flow meter, by providing the ability to
monitor lung function at home, provides potentially valuable
information for those who do not experience symptoms from airway
obstruction until it becomes severe or who mistake anxiety or hyperventilation as acute asthma. While some recommend routine use
of the peak flow meter, most people with asthma gain little
additional information since they readily perceive symptoms of chest
tightness, shortness of breath, wheeze, or cough when their asthma is
active. However, others do not perceive symptoms early in the course
of active asthma. This is especially true for patients with severe
chronic asthma. Those with longstanding severe chronic asthma
frequently are quite tolerant to living with airway obstruction that
would be uncomfortable for others with only occasional or less severe
asthma. The peak flow meter can provide potentially valuable
information for such individuals. This then provides a useful
supplement to the physician evaluations and office pulmonary function
appropriate for ongoing care of their asthma.
The peak flow meter measures the fastest flow of expired air that
can be produced with maximal effort. Since narrowed airways from
asthma will decrease the maximal rate of air flow, this is a measure
of active asthma. Therefore, the home peak flow meter, when used
properly by people with severe chronic asthma who perceive asthma
poorly, may tell you and your physician when airways are narrowing
from asthma. Progressively falling peak flow measurements also can
provide you and your physician with early warning signs of worsening
asthma and permit earlier and therefore more effective intervention
for acute exacerbations.
The instructions that come with the peak flow measuring device
should be read to understand the operation and care of the
instrument. Perform the peak flow by:
- First relax while taking a few slow moderately deep
breaths.
- Then breathe in as far as you can.
- Hold your breath while placing the mouthpiece in your mouth
beyond your teeth.
- Seal your lips tightly around the mouthpiece; keep your tongue
away from the mouthpiece.
- Blow out as hard and fast as you can.
- Repeat at least 2 more times.
- Record the best of 3 trials on your diary form unless that
value was so different from the values of the other 2 efforts that
you suspect something may have gone wrong. In that case, repeat
one more time and record the best effort that is reasonably
reproducible
Sometimes it is also useful to measure the peak flow before and
after you use your inhaled bronchodilator. In that case, repeat 3
measurements about 3 to 5 minutes after using your inhaler. Record
both the best of 3 measurements before and after the inhaled
bronchodilator.
Measurement of the peak flow before and after use of the
bronchodilator may be particularly useful in determining the
completeness of response to that treatment. Early identification of
incomplete response to the bronchodilator is important in knowing
when other measures are needed to prevent progression of asthma to
more severe or prolonged symptoms.
Title Page
|
|
