Asthma and the Correct Use of Peak Flow
Asthma is a chronic condition, one of a group of allergic conditions which includes both eczema and hayfever. In America it is the commonest of chronic childhood condition according to Asthma Carenet.org. In asthma the airways are over sensitive and at intervals become both narrow and inflamed. This makes normal respiration, usually expiration in particular, difficult. The cause or causes of asthma are not yet completely understood, though much research is beign undertaken, but often there are definite triggers which can set off an attack. These will vary from person to person.
During an asthma attack, whatever the cause or stimulus, the muscles in the airways tense and tighten, which cause the airways to narrow. There may also be inflammation and the presence of mucus. All this of course causes breathing difficulties. Such problems may in their turn cause a panic reaction and so make the condition worse.
Use of Peak Flow Meters
A peak flow meter measures the amount of air that flows out of the larger airways from the lungs. Despite the fact that it is unable to detect flow in the smaller pulmonary airways, readings from such a peak flow meter, especially when used together with an asthma diary, can enable both the medical staff and patients or perhaps their familes to recognize early changes that may be signs of worsening conditions in such asthmatic episodes. Proper and frequent use of a peak flow meter can give an alert about any tightening of the airways, even many hours before more obvious symptoms can be easily observed or experienced. The patient may not have observed any differences in their respiration, but the peak flow meter Peak Expiratory Rate reading may give a slightly different picture to the norm. This means that the relevent medication can be taken or increased as necesary and so a major attack can be circumvented. Testing can also be used to check responses to treatments, especially during an actual asthma attack, as well as generally detecting any possible worsening of the pulmonary function.
Variability in the peak flow measurements can also be shown. Many sufferers find things are worse at night. 40% asthmatics experience respiratory problems every night according to research by E.R.Sutherland ( 2005) on the subject of nocturnal asthma. He states that night time symptoms, which he found occurs in as many as 74% of asthmatics at least once weekly, indicate a relatively poor control of the condition and points out how a high proportion of asthma deaths occur at night.
Consistent monitoring will reveal how well controlling medication is working. A decrease of greater than 15% in flow as compared with the usual measurement could indicate night time asthma. In those whose asthma is well controlled the rates will consistently vary by less than 15% according to the American Academy of Allergy, Asthma and Immunology in their article ‘Tips to remember: Peak flow meter’.
Used correctly a peak flow meter can help a patient to discover exactly what it is that triggers attacks.It also means that medication regimes can be adjusted or added to and medical help sought when required. Their use is therefore helpful in cases of both mild and more severe asthma cases which require medication on a daily basis. Children as young as 4 years old are capable of being trained to use the meters effectively.The article ‘Asthma and the Peak flow Meter’ gives useful advice as to how the devices are best used. Patients are advised to:-
- Either stand or sit in an erect position.
- They should first check that the indicator on the dial is at zero and if not reset it.
- Then they should take a deep breath which completely fills the lungs.
- Hold this breath while placing the mouthpiece in the mouth, lightly biting it and also closing the lips around it while at the same time keeping the tongue tucked away so that it does not block the mouthpiece.
- The air should then be blasted out in a single breath, and as quickly as is possible.
- Remove the device from the mouth and record the number shown.
- This is then repeated twice more and the highest of the three readings can then be recorded in an asthma diary. This number is known in medical circles as the Peak Expiratory Flow or PEF.( sometimes referred to as Peak Expiratory Flow Rate or PEFR)
Normal PEF values can vary according to a person’s age, height, and gender. This means that it is individual differences that are important.rather than general trends. Using the meter regularly, both when there are and aren’t breathing difficulties, will provide information that can be used by physicians, even if the patient has no difficulties when seen.
Peak flow meters are an important diagnostic tool, even though they are incapable of measuring the vital capacity, unlike more complicated equipment, which is costly and may only be available in hospital or clinical situations. Instead the meters measure the rate at which air is expired, which gives some indication of how the airways have become narrowed. Unlike other devices such as spirometers they are inexpensive and readily available and it would be relatively easy to teach patients their correct use. Asthma is a serious condition and on occasions life threatening, but if asthma suffers are taught to use peak flow meters correctly, and have them available at home, then they will gradually become more knowledgable about their individual condition and how to treat it successfully. Therefore, all asthma patients, (and their parents if appropriate) should be taught carefully exactly how to use peak flow meters and asthma diaries so that they can better manage their own condition. Self care will then become an integral part of daily life and so suffers can take more responsibility for their own health with support from families and the relevant medical services .
There are many currect studies of asthma such as those being undertaken at the Asthma Research Center in Boston. These however tend to be quite complicated and to do with such things as the effects of genetics or the administration of particular drugs and their effects. A carefully research study into the long term effects on asthma of the regular use of peak flow meters by patients in their own homes would be perhaps of equal or even greater value, if this meant that patients become more self reliant and in control of their own bodies.
Asthma and the Peak Flow Meter, the Cleveland Clinic, WebMD, 2010, available from http://www.webmd.com/asthma/guide/peak-flow-meter, accessed 8th February 2010
Childhood Asthma Research and Education, Astmacarenet.org, available from http://www.asthma-carenet.org/ , accessed 8th February 2010.
Current Studies, The Asthma Research Center at Brigham and Women’s Hospital , Boston,.available from http://www.asthmabwh.org/currentStudies.php acessed 8th February 2010
Sutherland, E.,December 2005, Nocturnal Asthma, the Journal of Allergy and Clinical Immunology ,116 ( 6), pages 1179 -86
Tips to remember: Peak flow meter, 2010, The American Academy of Allergy, Asthma and Immunology, available from http://www.aaaai.org/patients/publicedmat/tips/whatispeakflowmeter.stm, accessed 8th February 2010.