Respiratory pathologies lead to severe disorders throughout the body. This is due to a lack of oxygen and an excess of carbon dioxide. Serious respiratory disorders are observed in chronic diseases of the lungs and bronchi. In addition, other pathologies can lead to hypoxia. Among them - laryngospasm, an increase in tonsils of the 2nd and 3rd degree with tonsillitis, getting into the respiratory tract of a foreign body , etc.
To distinguish between diseases, various research methods are carried out. One of them is peak flowmetry. This diagnostic procedure is performed with suspected bronchial asthma, chronic obstructive pulmonary disease, emphysema. People suffering from these pathologies know firsthand about such a device as a peak flow meter. What is it and how to use it, the doctor must explain. Treatment tactics depend on the performance of this device.
Peak flow meter - what is it?
As you know, the main method for determining respiratory functions is spirometry. Nevertheless, the device that is necessary for this study is quite expensive and is available only in the clinic. So that patients can measure respiration at home, they invented a more convenient device - a peak flow meter. What is this, every patient with bronchial asthma and COPD knows. After all, such diseases belong to pathologies in which constant monitoring of the condition is necessary. This is especially true for patients with an established diagnosis of moderate and severe degree. Thanks to peak flowmetry, the stage of the disease can be determined. Indeed, the severity is set based on such an indicator as peak expiratory flow rate (PSV). A peak flow meter is a portable device that every patient has. With it, you can measure PSV both during seizures and at rest. Thanks to the peak flowmeter, disease control is carried out. If the parameters of this device change, you should consult a doctor in order to correct the treatment.
The principle of the peak flow meter
The action of the peak flow meter is based on the movement of the arrow under pressure on it with an air stream. The device has a scale from 0 to 1000. With it, it is determined how much air a patient can exhale in 1 minute. Thus, it is possible to approximately calculate the vital capacity of the lungs. A mouthpiece is attached to the device. It is in him that the patient exhales. In addition to numbers on the device there are colored marks. They are necessary to assess the state of respiratory function.
Despite the fact that the operating principle of the peak flow meter is quite simple, in some cases errors are noted when using it. More often this applies to pediatric patients who need to be explained how to exhale. To make it clear to the child, they tell him to blow as if you were extinguishing candles on a cake. Regardless of the age of the patient, all patients suffering from bronchial asthma should attend special classes organized in the clinic. Thanks to them, people learn about the correct lifestyle, types of drugs and indications for their appointment. Why do you need a peak flow meter, what is it and how to use it, they also explain here. Also, patients are informed about the target values of this device and expressed deviations from the norm.
Varieties of peak flow meters: differences
The peak flow meter is an expiratory flow meter that was created in the 1950s by Professor Wright. This device had the same mechanism of action as the modern apparatus, but was distinguished by its large size. In 1975, the device was improved. The peak flow meter was called the “mini-wright” apparatus, it was small in size and could be used at home.
Currently, there are several types of devices manufactured by various medical companies. Nevertheless, they differ slightly from the “mini-wright". Omron peak flow meter is considered quite popular. This company also produces other medical devices. Among them are a tonometer, a phonendoscope, inhalers, etc. Omron peak flow meters have proven themselves in the market due to their ease of use and good quality.
In addition to the usual devices, the mechanism of which is based on air pressure, this company also produces electronic devices. They are convenient for patients who cannot independently regulate breathing (children, the elderly).
The Philips flowmeter is not inferior in quality. It is slightly different in shape (rectangular) and also has a stand. Due to this, the device can not be kept at the time of the study.
How to use the peak flow meter yourself?
This appliance must be used as follows:
- Remove the peak flow meter from the packaging.
- Verify that the arrow is at “0”.
- Make the maximum breath a full chest.
- Cover the mouthpiece with your lips, while gently holding it with your teeth. Language should not touch the appliance.
- To exhale a single exhale with maximum force.
- Remove the mouthpiece from the mouth.
- Mark the PSV indicator.
A similar procedure should be repeated 3 times in a row. After this, the indicators should be recorded in a special diary, which are kept by patients suffering from bronchial asthma. The average peak expiratory flow rate is noted. With a low PSV value (less than 60%), inhalation should be done with a fast-acting drug. The electronic flowmeter is characterized in that the value of the peak expiratory flow rate is automatically calculated and displayed on the screen. As with a mechanical device, the study must be repeated 3 times and note the average value of PSV.
What do the colored stripes on the peak flow meter mean?
Regardless of the manufacturer, there are color marks on all peak flow meters. They are located on the side of the arrow. Thanks to them, one can judge the degree of bronchial obstruction. If PSV is within the green color range (80-100%), this means that the disease is treatable and controlled. The indicators of this zone indicate the stage of remission and correspond to the volume of exhaled air equal to 320-400 ml. If PSV is 60-80% of the norm, then on the device this value is within the yellow color. A similar result means that the disease is in an acute stage. In this case, clinical manifestations such as coughing, shortness of breath when walking, sleep disturbance can be observed. The yellow zone is a warning that treatment should be reviewed. Critical indicators are those that are within the red color. At the same time, PSV is less than 60% of the norm. Such a result is an occasion for urgent medical attention.
Norm indicators for peak flowmetry
Peak flowmeter targets should be in the green zone. If the volume of exhaled air is more than 320 ml, then the scatter of PSV indicators does not exceed 20% per day. This result is observed in patients with a controlled course of bronchial asthma and chronic obstructive pulmonary disease. PSV indicators correspond to the forced expiratory volume during spirometry. The norm of both indicators in healthy people is 100%. With physical exertion and respiratory diseases, it can slightly decrease. If a patient is diagnosed with COPD or bronchial asthma, then a PSV of 80% is the norm of exhalation. The peak flow meter registers this indicator 3 times. Slight fluctuations in the daily rate of peak expiratory flow mean that airway obstruction is not pronounced. In this case, correction of treatment is not required.
Peak flowmetry indicators for pathologies of the respiratory system
With severe respiratory dysfunction, peak flow metrics are below 80%. That is, after exhaling, the arrow is in the yellow or red zone. Such changes are observed only in chronic pathologies of the respiratory system. The most common cause is bronchial obstruction. In some cases, a decrease in PSV can be observed with restrictive disorders. Similar changes are found in severe inflammatory diseases of the lung tissue (focal pneumonia, tuberculosis). In contrast to chronic obstructive pathologies, these disorders are reversible.
Differential diagnosis between COPD and bronchial asthma
Chronic bronchial obstruction occurs in COPD and bronchial asthma. Both diseases are accompanied by a decrease in PSV. Therefore, peak flowmetry does not always distinguish between these pathologies. Nevertheless, there is a difference between these diseases. In bronchial asthma, the value of PSV often fluctuates. If there are no asthma attacks, then the peak expiratory flow may be normal. With an exacerbation, PSV decreases sharply and is restored immediately after taking bronchodilator drugs. COPD is characterized by a progressive course, lack of communication with exposure to allergens. After taking the drugs, PSV does not change as much as with asthma.
How often do I need to use a peak flow meter?
Regular peak flow measurements can help prevent seizures. For reliability, it is recommended to measure PSV at least 2 times a day - in the morning and in the evening. The frequency of the study depends on the severity of the disease. It is advisable to use a peak flow meter with interchangeable mouthpieces. This will help to avoid infection of the oral mucosa.