Pulmonary Function Test Interpretation

Assessment of Airflow Obstruction and Restrictive Lung Diseases

Pulmonary function tests (PFTs) are essential diagnostic tools used to assess lung function, detect respiratory conditions, and monitor disease progression. These tests help distinguish between obstructive and restrictive lung diseases.

Types of Pulmonary Function Tests

• Spirometry: Measures airflow to diagnose obstructive lung diseases like COPD and asthma.
• Lung volumes: Evaluates total lung capacity to identify restrictive conditions such as pulmonary fibrosis.
• Diffusion capacity: Assesses gas exchange efficiency in conditions like pulmonary hypertension.

Interpreting PFT Results

Proper interpretation of PFTs involves analyzing key parameters:

• FEV1/FVC Ratio: A low ratio (<70%) suggests obstructive lung disease.
• Total Lung Capacity (TLC): Reduced TLC (<80% predicted) indicates restrictive lung disease.
• DLCO (Diffusing Capacity of the Lung for Carbon Monoxide): A decreased DLCO may suggest interstitial lung disease or pulmonary vascular conditions.

Clinical Applications

PFTs aid in the diagnosis, management, and prognosis of various pulmonary conditions, guiding treatment decisions such as bronchodilator therapy or pulmonary rehabilitation.