Pulmonary Function Testing
Assessment of lung function through spirometry to evaluate asthma and respiratory conditions.
Overview
Pulmonary function testing (PFT), particularly spirometry, measures how well the lungs work. It's essential for diagnosing and monitoring asthma and other respiratory conditions.
spirometry
description
Measures how much air you can breathe in and out, and how fast you can exhale
measurements
fev1
Forced expiratory volume in 1 second - amount of air exhaled in first second
fvc
Forced vital capacity - total amount of air exhaled
fev1 Fvc
Ratio of FEV1 to FVC - indicates airflow obstruction
peak Flow
Maximum speed of exhalation
interpretation
- Normal: FEV1/FVC ratio >70-80% (age-dependent)
- Obstruction: Reduced FEV1/FVC ratio suggests asthma or COPD
- Restriction: Reduced FVC suggests other lung conditions
bronchodilator Response
description
Test performed before and after using a bronchodilator (albuterol)
process
- Baseline spirometry performed
- Bronchodilator administered
- Repeat spirometry after 15-20 minutes
- Compare results
positive
- Improvement in FEV1 of ≥12% and ≥200mL
- Suggests reversible airflow obstruction (asthma)
- Helps distinguish asthma from other conditions
negative
May suggest other conditions or need for different evaluation
prep
medications
hold
- Short-acting bronchodilators: 6-8 hours before
- Long-acting bronchodilators: 12-24 hours before (discuss with provider)
- Inhaled corticosteroids: Usually continue, but discuss with provider
avoid
- Caffeine: 4-6 hours before (can affect results)
- Heavy meals: 2 hours before
- Strenuous exercise: 1 hour before
day Of
- Wear comfortable clothing
- Arrive well-rested
- Follow provider's specific instructions
uses
diagnosis
- Confirming asthma diagnosis
- Distinguishing asthma from other conditions
- Assessing severity
monitoring
- Tracking asthma control over time
- Assessing response to treatment
- Identifying worsening disease
limitations
- Requires patient cooperation and effort
- May not be suitable for very young children
- Results can be affected by technique
- Normal results don't rule out asthma if symptoms are intermittent
Ready to Get Started?
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