Bronchial relaxation test

The bronchodilation test is to determine the reversibility of airway obstruction by measuring the change of FEV1 before and after inhalation of bronchodilators. It is mainly used for the diagnosis of bronchial asthma. For patients with an FEV1 <70% predicted value, a diastolic test can be performed when asthma is clinically suspected. This test is for acute or chronic bronchitis, bronchial asthma and chronic obstructive pulmonary disease. Basic Information Specialist classification: Respiratory examination classification: pulmonary function test Applicable gender: whether men and women apply fasting: not fasting Tips: Maintain a normal diet and schedule. Normal value The increase in FEV1 in normal adults after inhalation of β2 agonists was <200 ml, and the improvement rate was <15%. Clinical significance Clinical use is used to examine the reversibility of pulmonary function airway obstruction and to assist in the diagnosis of bronchial asthma. 1. FEV1 increased by >15% after inhalation of bronchodilator for 20 min, and the absolute value exceeded 200 ml for bronchodilation test. Indicates an increase in airway reactivity. Helps diagnose asthma. 2. To determine whether the diastolic test is positive or not, it is necessary to consider both the percentage and the absolute value of the change before and after diastolic. Because the percentage change is affected by the baseline value before diastole, if the baseline value before diastole is very low, a slight increase after diastole will make the percentage change very much; on the contrary, the base value before diastole is larger, and after diastole, it needs a considerable increase. In order to make a significant change in the percentage. 3. Positive bronchodilation test is helpful for the diagnosis of asthma, but the negative result is not enough to negate the diagnosis of asthma, especially in patients with advanced severe disease or asthma with chronic bronchitis. In some patients, there was no significant change in FEV1 after diastolic test, but the symptoms improved and the exercise tolerance increased. It may be due to the decrease of RV, the increase of VC, the function of diffusion, and the change of ventilation/blood flow ratio. Therefore, the negative diastolic test can not rule out the treatment of bronchodilator. The benefits. 4. Approximately 10% of patients with COPD may be positive for bronchodilation. High results may be diseases: pollen allergic asthma, bronchial asthma, chronic obstructive pulmonary disease considerations (1) Before the test, all bronchodilators were deactivated for 12 hours except for oral glucocorticoids, and the short-acting β2 agonists were stopped for at least 6 hours. (2) In addition to FEV1, the reactivity to bronchodilators can also be evaluated using PEF, FVC, FEV1/FVC, FEF 25% to 75%, Vmax 50%, SGAw (compared to airway conduction). (3) Disabled in patients with severe heart disease, severe hypertension, severe arrhythmia, and severe cardiac insufficiency. Inspection process The subject first measured the basic FEV1 (or PEF), then inhaled 200-400 μg of the β2 receptor agonist (such as salbutamol) with MDI, and repeatedly measured FEV1 (or PEF) 15 to 20 minutes after inhalation. In order to ensure the accuracy and reliability of the test results, the patient's inhalation technique should be checked before the formal test. For those who have inhaled MDI for the first time or who do not have a good grasp of the inhalation technique, the physician or technician should demonstrate it personally and teach the patient to use MDI correctly. If the improvement rate is ≥15%, and the absolute value of FEV1 is increased by >200ml (with FEV1 as the measurement index), the test is considered to be positive. Subjects first measured basal FEV1 (or PEF), then inhaled 200-400 μg of β2-agonist (such as salbutamol) with MDI, and repeated measurements of FEV1 (or PEF) 15 minutes after inhalation. In order to ensure the accuracy and reliability of the test results, the patient's inhalation technique should be checked before the formal test. For the first inhalation of MDI or the inability to inhale the technician or the technique, the doctor should personally demonstrate the use of MDI. Not suitable for the crowd 1. Children without asthma. 2, pregnant women. 3, other people: disabled in patients with severe heart disease, severe hypertension, severe arrhythmia, severe heart failure. Adverse reactions and risks It generally does not cause complications and harm.