Significance and study objectives
The study of unforced respiratory volumes and flows is the primary method for diagnosing and documenting pulmonary function. It is prescribed for all patients with suspected chronic obstructive pulmonary disease to achieve the following objectives:
- Detection of airflow limitation.
- Assessment of the severity of obstructive changes.
- Classification of COPD based on the data obtained.
Recommendation strength level: C (evidence reliability level — 4).
Criteria for diagnosis confirmation
To confirm the presence of expiratory airflow limitation, spirometry with a bronchodilator test is used.
The main diagnostic criterion here is the post-bronchodilator FEV₁/FVC ratio of less than 0.7. This parameter indicates the presence of persistent airway obstruction.
Recommendation strength level: C (evidence reliability level — 5).
Role of spirometry in bronchial asthma
In bronchial asthma, spirometry and peak flowmetry serve the purposes of monitoring and assessing the patient's condition:
- Peak flowmetry: a key method for early detection of obstruction and self-monitoring, measuring peak expiratory flow. Every asthma patient should have an individual peak flow meter.
- Spirometry (PFT): FEV₁ and PEF parameters are used to assess the severity of the disease course, as well as in provocation tests to screen for bronchial hyperreactivity.
Additional tests and other examinations
Patients over 18 years of age with suspected asthma who have normal baseline spirometry parameters, a negative bronchodilator test, and a negative exercise test are prescribed a pharmacological provocation test. Its purpose is to detect latent bronchial hyperreactivity (level C, evidence — 5).
In addition, in non-fibrotic hypersensitivity pneumonitis, spirometry values may fall within the normal range, so the key functional impairment in such cases may be a decrease in DLCO (diffusing capacity of the lungs).
Less than seventy (FEV₁/FVC < 0.7) after a bronchodilator indicates obstruction, which forms the basis of a COPD diagnosis.
Class and exam questions
Which spirometry parameter is the main criterion for COPD?
The main diagnostic criterion is the post-bronchodilator FEV₁/FVC ratio of less than 0.7, confirming expiratory airflow limitation.
Why do patients with bronchial asthma need an individual peak flow meter?
A peak flow meter is used for daily monitoring and early detection of obstruction, measuring peak expiratory flow as part of self-monitoring.
Who needs spirometry with provocation to detect hyperreactivity?
Such a test is performed in patients over 18 years of age with suspected bronchial asthma if they have normal baseline spirometry results and negative standard reversibility and exercise tests.
What else to study on this topic
- Assessment of forced expiratory volume in the first second (FEV₁)
- Performing and evaluating the bronchodilator test
- Significance of diffusing capacity of the lungs (DLCO) in non-fibrotic hypersensitivity pneumonitis
- Methodology and interpretation of peak flowmetry
- Bronchoconstrictor tests with exercise and pharmacological agents
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