[Pulmonary function testing in asthma]

Area of Science:

• Pulmonology
• Respiratory Medicine
• Diagnostic Medicine

Background:

• Asthma diagnosis frequently relies on spirometry with a bronchodilator test.
• Variable airflow obstruction and airway hyperresponsiveness are key asthma indicators.
• Emerging guidelines increasingly support measuring exhaled nitric oxide for asthma diagnosis.

Purpose of the Study:

• To review diagnostic methods for asthma, including spirometry, PEF variability, bronchial challenge tests, and exhaled nitric oxide.
• To highlight techniques for identifying peripheral airway involvement in asthma, such as oscillometry and nitrogen washout.
• To emphasize the importance of continued investigation in persistent asthma cases, even with negative initial test results.

Main Methods:

• Review of spirometry with bronchodilator testing.
• Assessment of peak expiratory flow (PEF) variability.
• Evaluation of bronchial challenge tests.
• Analysis of exhaled nitric oxide measurements.
• Exploration of oscillometry and nitrogen washout for peripheral airway assessment.

Main Results:

• Spirometry with bronchodilator is the standard diagnostic test for asthma.
• PEF variability and bronchial challenge tests can reveal airflow obstruction and hyperresponsiveness.
• Exhaled nitric oxide measurement is gaining traction in asthma diagnostic guidelines.
• Peripheral airway involvement, common in asthma, may be detected by oscillometry and nitrogen washout, even with normal spirometry.

Conclusions:

• A comprehensive approach utilizing various diagnostic tools is crucial for accurate asthma diagnosis.
• Investigative persistence is vital when clinical suspicion of asthma remains despite negative initial findings.
• Advanced techniques like oscillometry and nitrogen washout can identify subtle airway involvement.