Pulmonary Function Test Flashcards
What do pulmonary function tests (PFTs) measure?
How well the lungs work.
What are some common symptoms that may prompt a pulmonary function test?
- Dyspnea
- Cough
- Cyanosis
- Wheezing
What is the purpose of performing pulmonary function tests?
- Look for evidence of respiratory disease
- Assess for progression of lung disease
- Monitor treatment efficacy
- Evaluate patients pre-operatively
- Monitor for toxic side effects of drugs
Define Expiratory Reserve Volume (ERV).
The maximal volume of air that can be exhaled from the end-expiratory position.
What does Total Lung Capacity (TLC) refer to?
The volume in the lungs at maximal inflation, the sum of VC and RV.
What is Vital Capacity (VC)?
The volume of air breathed out after the deepest inhalation.
Define Inspiratory Capacity (IC).
The sum of IRV and TV.
What is Forced Vital Capacity (FVC)?
The determination of the vital capacity from a maximally forced expiratory effort.
What is the normal FEV1/FVC ratio in healthy patients?
About 80%.
An FEV1/FVC ratio of less than 80% suggests what type of lung disease?
Obstructive lung disease.
What indicates a restrictive lung disease based on FEV1/FVC?
Typically has normal or increased FEV1/FVC.
What is the flow volume loop used for in PFTs?
To visualize lung function and identify patterns of obstruction or restriction.
Describe the PFT obstructive pattern.
- Decreased FEV1
- Normal or decreased FVC
- Decreased FEV1/FVC
What does bronchodilator responsiveness indicate?
An increase in FEV1 by 12% following bronchodilator use suggests asthma.
What characterizes a restrictive pattern in PFTs?
- Decreased TLC
- Decreased FEV1
- Decreased FVC
- Normal FEV1/FVC
- Low DLCO
What is DLCO?
Diffusion capacity for carbon monoxide, indicating how well oxygen passes from the air sacs of lungs to blood.
What is the practical interpretation step for FEV1/FVC ratio?
- FEV1/FVC <70%: Obstructive Pattern
- FEV1/FVC ≥70%: Normal or Restrictive disease
What defines the severity of obstruction according to GOLD criteria for COPD?
- FEV1 80-100% predicted: Mild (Stage 1)
- FEV1 50-80% predicted: Moderate (Stage 2)
- FEV1 30-<50% predicted: Severe (Stage 3)
- FEV1 <30% predicted: Very severe (Stage 4)
What is the ATS general criteria for the severity of obstruction?
- FEV1 >70% predicted: MILD
- FEV1 60-70% predicted: MODERATE
- FEV1 50-60% predicted: MODERATELY SEVERE
- FEV1 35-50% predicted: SEVERE
- FEV1 <35% predicted: VERY SEVERE
What does a TLC of less than 80% indicate?
Restrictive disease.
What is the normal range for Total Lung Capacity (TLC)?
80-120% of predicted.
What does TLC greater than 120% indicate?
Hyperinflation.
Fill in the blank: FEV1/FVC ratio of less than 70% indicates _______.
Obstructive Pattern.
