A peak flow meter is a portable, hand-held plastic device used to monitor the flow of air from your lungs. It measures your ability to push air out of your lungs. Peak flow meters are available in two ranges. A low range meter is used for small children whereas the standard range one is used for teenagers and adults.
Who Can Use A Peak Flow Meter?
It can be used by anyone even without a prescription. Patients with moderate or severe asthma can benefit by its use. These instruments are also useful for those who have night-time asthma. People who have been recently diagnosed for asthma can also use this meter. It can form an important part of asthma management plan and help asthma patients adjust their medication. A peak flow meter can be used by children, even as young as three years as well as people with chronic bronchitis and emphysema. But it may not be very helpful for patients with mild asthma who do not require daily medication.
What Is The Need Of Measuring Your Peak Flow Rate?
Peak flow meter readings are useful in the management of asthma. These measurements are used to monitor your asthma and prescribe medicines accordingly in order to keep your asthma under control. The readings of a peak flow meter can help your physician make necessary changes in the way drugs are administered to you. The meter’s readings are an indication of how well your asthma management plan is working. The readings are useful even if you are improving as they help your physician decide on reducing your drug intake. On the other hand, if your asthma is worsening, a peak flow meter can show those gradual changes before you start experiencing them. This will in turn help your physician adjust your drug doses to prevent any critical situation. The causes and triggers of your asthma, whether at home or at the work place, can also be determined using these meters. Using this device during an attack can help establish the intensity of the attack and in deciding between taking medications and seeking emergency help.
When Should It Be Used?
People use peak flow meters in the morning and in the evening. This helps in observing the night-time effect of asthma, even in asymptomatic patients. People having asthma can experience a significant drop in lung function during the night and the meter reading can give the right estimate of this drop. A drop between morning and evening readings is an indicative of deteriorating lung function.
Readings can also be noted prior to and on conclusion of exercise to determine if the patient has exercise-induced asthma. It can also be used before and after taking medication to check the effects of the medication. A peak flow meter test can be performed on experiencing asthma symptoms, especially if they come without any warning signals.
How To Use A Peak Flow Meter?
1) Set the arrow or the sliding marker to the baseline (either zero or the lowest number on the scale) before each use.
2) Stand straight and remove any gum or food from your mouth. Breathe deeply and put the mouthpiece of the meter into your mouth. Close your lips tightly over the mouthpiece and blow out as fast and hard as possible in one single breath, until you have emptied your lungs.
3) The marker will move along the numbered scale under the force of this exhaled air. Note down the reading.
4) Repeat this procedure two more times. Remember to reset the marker each time. If all the three values are in the same range, then you are using the meter correctly.
5) Record the highest of the three readings, not the average, and measure close to the same time, everyday.
6) Prepare a chart of your peak flow rates and consult your physician.
What Do The Peak Flow Rates Indicate?
A normal peak flow rate is based on a person’s height, weight, age and sex. By comparing the patient with peak flow rates from people not having breathing problems, a standardized normal reading for the patient can be obtained. Once you have determined your regular and expected peak flow rates, you can monitor any deviations easily. A daily log will help you monitor your lung function. A low reading, about 80 to 85% of your personal best, is an indication of increased sickness. It is a sign of reduced lung capacity due to inflammation or constriction of the airways.
Peak flow rates can be interpreted from the three common zones of measurement – green, yellow and red. A reading in the green zone indicates you are doing well and your asthma is well under your control. Your lungs are performing at 80 to 90% of your usual peak flow rate.
If your lungs are functioning between 50 to 80% of your personal best, you will observe a reading in the yellow zone. It indicates a narrowing of your bronchial tubes signaling caution. You should consult your physician and accordingly adjust your management plan.
A reading in the red zone indicates that your lungs are functioning at less than 50% of your usual peak flow rates. This could mean a severe narrowing of the airways and require the use of rescue medication right away.