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Questions and Answers
What is the main purpose of measuring the diffusing capacity of the lungs for carbon monoxide (DLCO)?
What is the main purpose of measuring the diffusing capacity of the lungs for carbon monoxide (DLCO)?
Which factor in Fick's equation would result in a decrease in gas diffusion across the alveolar membrane?
Which factor in Fick's equation would result in a decrease in gas diffusion across the alveolar membrane?
In which condition would a DLCO test likely show values below 60% of predicted?
In which condition would a DLCO test likely show values below 60% of predicted?
What percentage of predicted DLCO would typically indicate a normal function?
What percentage of predicted DLCO would typically indicate a normal function?
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What is the effect of increased solubility of a gas on its diffusion across the alveolar membrane according to the principles outlined?
What is the effect of increased solubility of a gas on its diffusion across the alveolar membrane according to the principles outlined?
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What are the three basic categories for classifying pulmonary diseases based on pulmonary function tests?
What are the three basic categories for classifying pulmonary diseases based on pulmonary function tests?
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Which pulmonary function test is primarily used to assess airway patency and airflow?
Which pulmonary function test is primarily used to assess airway patency and airflow?
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In addition to airflow, what other parameters are specifically measured during pulmonary function tests?
In addition to airflow, what other parameters are specifically measured during pulmonary function tests?
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What is the primary purpose of maximal inspiratory pressure testing in pulmonary function tests?
What is the primary purpose of maximal inspiratory pressure testing in pulmonary function tests?
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Which test measures the lung's ability to transfer gas from the alveoli to the bloodstream?
Which test measures the lung's ability to transfer gas from the alveoli to the bloodstream?
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What key recommendation does the American Thoracic Society provide regarding spirometry test data presentation?
What key recommendation does the American Thoracic Society provide regarding spirometry test data presentation?
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Which of the following tests specifically evaluates exercise capacity?
Which of the following tests specifically evaluates exercise capacity?
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What does spirometry specifically measure in relation to lung function?
What does spirometry specifically measure in relation to lung function?
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What characterizes restrictive lung diseases?
What characterizes restrictive lung diseases?
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Which statement correctly describes the bronchodilator effect in asthma?
Which statement correctly describes the bronchodilator effect in asthma?
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What differentiates asthma from COPD in terms of reversibility tests?
What differentiates asthma from COPD in terms of reversibility tests?
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Which of the following is NOT classified under intrinsic lung diseases?
Which of the following is NOT classified under intrinsic lung diseases?
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What is the primary characteristic of chronic obstructive pulmonary disease (COPD) as identified in the content?
What is the primary characteristic of chronic obstructive pulmonary disease (COPD) as identified in the content?
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Which condition is classified under extrinsic pulmonary diseases?
Which condition is classified under extrinsic pulmonary diseases?
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What happens in restrictive lung diseases concerning lung tissue compliance?
What happens in restrictive lung diseases concerning lung tissue compliance?
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What does the reversibility formula for FEV1 primarily measure?
What does the reversibility formula for FEV1 primarily measure?
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In the flow-volume loop of a restrictive lung disease patient, how does the loop typically present?
In the flow-volume loop of a restrictive lung disease patient, how does the loop typically present?
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Which spirometry result is indicative of restrictive lung disease?
Which spirometry result is indicative of restrictive lung disease?
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How is disease progression typically monitored in restrictive lung diseases?
How is disease progression typically monitored in restrictive lung diseases?
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What pattern of the FEV1/FVC ratio is expected in restrictive lung disease?
What pattern of the FEV1/FVC ratio is expected in restrictive lung disease?
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What does the term decreased lung compliance imply?
What does the term decreased lung compliance imply?
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Which indicator is considered significant for monitoring disease progression in obstructive lung disease?
Which indicator is considered significant for monitoring disease progression in obstructive lung disease?
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What is typically seen in the spirometry results of patients with both obstructive and restrictive lung disease?
What is typically seen in the spirometry results of patients with both obstructive and restrictive lung disease?
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What role does elastic recoil play in airflow during restrictive lung disease?
What role does elastic recoil play in airflow during restrictive lung disease?
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Which of the following is commonly assessed to monitor disease progression in neuromuscular restrictive diseases?
Which of the following is commonly assessed to monitor disease progression in neuromuscular restrictive diseases?
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What implication does an impaired DLCO have on lung disease?
What implication does an impaired DLCO have on lung disease?
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What is NOT a purpose of spirometry assessments?
What is NOT a purpose of spirometry assessments?
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Which of the following is an essential skill for a physiotherapist regarding spirometry?
Which of the following is an essential skill for a physiotherapist regarding spirometry?
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What is one of the main benefits of using spirometry data?
What is one of the main benefits of using spirometry data?
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Which of the following aspects of lung function is NOT typically assessed by spirometry?
Which of the following aspects of lung function is NOT typically assessed by spirometry?
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Which reference document specifically provides a technical standard for interpreting routine lung function tests?
Which reference document specifically provides a technical standard for interpreting routine lung function tests?
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Which of the following references discusses bronchodilator reversibility in asthma and COPD?
Which of the following references discusses bronchodilator reversibility in asthma and COPD?
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What is a primary goal of spirometry monitoring?
What is a primary goal of spirometry monitoring?
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What does an FEV1/FVC ratio of < 0.7 indicate?
What does an FEV1/FVC ratio of < 0.7 indicate?
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Which classification represents moderate airflow limitation according to GOLD criteria?
Which classification represents moderate airflow limitation according to GOLD criteria?
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What is the lower limit of normal (LLN) calculated based on?
What is the lower limit of normal (LLN) calculated based on?
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What would classify an individual as having severe airflow limitation?
What would classify an individual as having severe airflow limitation?
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When is Total Lung Capacity (TLC) considered normal?
When is Total Lung Capacity (TLC) considered normal?
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What is a limitation of using a fixed cutoff for airflow obstruction?
What is a limitation of using a fixed cutoff for airflow obstruction?
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What does the Z-score indicate about lung function?
What does the Z-score indicate about lung function?
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How is 'very severe' airway obstruction defined in the Classification of Severity of Airflow Limitation?
How is 'very severe' airway obstruction defined in the Classification of Severity of Airflow Limitation?
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What factor does NOT affect the classification of expected values for lung function?
What factor does NOT affect the classification of expected values for lung function?
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According to ATS/ERS standard, how is a mild impairment classified?
According to ATS/ERS standard, how is a mild impairment classified?
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What is the spread of expected values around the mean expressed as?
What is the spread of expected values around the mean expressed as?
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What FEV1 percentage classifies someone as having 'moderate airflow limitation' according to the GOLD criteria?
What FEV1 percentage classifies someone as having 'moderate airflow limitation' according to the GOLD criteria?
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Which of the following indicates normal diffusing capacity for carbon monoxide (DLCO)?
Which of the following indicates normal diffusing capacity for carbon monoxide (DLCO)?
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What would classify an individual with a Z-score less than -4.1?
What would classify an individual with a Z-score less than -4.1?
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Study Notes
Pulmonary Function Tests
- Pulmonary function tests (PFTs) are investigations used to evaluate the airways, respiratory musculature, and lung tissues.
- PFTs measure lung volumes and capacities, gas flow rates, gas diffusion and distribution.
- PFTs are used to classify lung diseases into obstructive, restrictive and mixed categories.
Intended Learning Outcomes
- Students will be able to recognize and distinguish different pulmonary function tests.
- Students will understand how to conduct an accurate spirometry test.
- Students will interpret numerical and graphical spirometry data.
- Students will recognize spirometry patterns associated with restrictive and obstructive lung diseases.
- Students will appreciate the American Thoracic Society recommendations for presenting spirometry data.
- Students will appropriately use spirometry data to evaluate physiotherapy interventions.
Lung Diffusion Capacity Test (DLCO)
- DLCO is a measurement to assess the lung's ability to transfer gas from inspired air to the bloodstream.
- It's called the diffusing capacity of the lungs for carbon monoxide (DLCO).
- Inhaled carbon monoxide (CO) is used because it has a higher affinity for hemoglobin than oxygen (O2).
- The test requires the patient to hold their breath for 10 seconds to measure the CO uptake.
Fick's Equation
- Factors affecting gas diffusion across the alveolar membrane:
- Surface area of the membrane
- Membrane thickness
- Solubility of the gas
- Driving pressure/pressure gradient
DLCO Results
- DLCO is indicated to evaluate parenchymal and non-parenchymal lung diseases, such as obstructive, restrictive, and pulmonary vascular diseases.
- Results are interpreted in conjunction with spirometry and TLC values.
- Normal DLCO is >75% predicted, up to 140%.
- Mild DLCO is 60% to LLN.
- Moderate DLCO is 40% to 60%.
- Severe DLCO is <40%.
How DLCO is Conducted
- Techniques include single breath method, intrabreath method, and rebreathing technique.
- The patient sits with a clip on the nose.
- A mouthpiece is attached for the test gas.
- The patient takes a few normal breaths.
- The patient exhales completely, inhales deeply, and holds the breath for 10 seconds.
- The patient then exhales for 3-5 seconds.
What is Spirometry?
- Spirometry is the study of gas flow and lung volumes (ventilatory function).
- It measures the flow and volume of air entering and leaving the lungs.
- It compares lung function results to reference values.
- It measures the impact of pulmonary diseases (e.g. asthma, COPD, cystic fibrosis).
- It detects early changes in lung function (e.g., airway narrowing).
- It evaluates the response to medicine (e.g., bronchodilator).
- It determines the ability to tolerate medical or surgical procedures
Spirometry (Physiological Test)
- Spirometry involves measuring the maximal volume of air inhaled and exhaled.
- It also measures volumes as a function of time, elastic resistance and airway resistance.
Indications for Spirometry
- General respiratory health screening.
- Identifying individuals at risk for pulmonary disease.
- Assessing pre-operative risk.
- Evaluating disease prognosis.
- Assessing disease effects on lung function.
- Evaluating disability/impairment.
- Monitoring disease progression and exacerbation.
- Evaluating the response to interventions (e.g., exercise programs, medications, surgery).
- For surveys and pre-employment/at-risk occupations lung health monitoring.
Spirometry Precautions
- Spirometry involves physical effort, increasing myocardial demand and causing the generation of intrathoracic/intra-abdominal/intracranial pressure.
- Risks are related to the impact on thoracic organs, venous return, and systemic blood pressure and chest wall and lung expansion.
Relative Contraindications for Spirometry
- Pain.
- Recent eye, thoracic, or abdominal surgery.
- Recent myocardial infarction, uncontrolled hypertension or embolism.
- Recent cerebrovascular hemorrhage or known cerebral/abdominal aneurysm.
- Pneumothorax.
- Haemoptysis of unknown origin.
- Acute disorders affecting test performance (e.g., fever, vomiting, dizziness, nausea).
Preparing for a Spirometry Test
-
Environment:
- Stable temperature.
- Standardized pressure (barometer).
- Quiet and comfortable.
-
Hygiene:
- Hand hygiene.
- Disposable and single-patient filters/gloves.
-
Equipment:
- Calibrated spirometry machine.
- Arm chair (sitting).
- Nose clip.
- Filter and turbine (or combined).
How to perform a Spirometry Test
- Patient performs 3 trials, choosing the best, including maximal inspiration & expiration, with appropriate instructions/prompting.
- Common errors include incorrect inspiration to TLC, premature expiration and variable effort.
Procedures for Forced Vital Capacity (FVC) Maneuvers
- Dispenses hand sanitizer and confirms patient details (including allergies and respiratory symptoms).
- Checks the requisition for relative contraindications.
- Informs the patient how to position and breathe.
- Demonstrates correct test procedure with verbal encouragement.
- Records three trials, choosing the best.
Spirometry Test Results
- Volume refers to the amount of air contained in the lungs and expelled at various times in a respiratory cycle.
- Speed refers to how fast air is expelled from the lungs at different times in the respiratory cycle.
Spirometric Report Format
- Shows numerical values (e.g., FVC, FEV1, FEV1/FVC).
- Includes a flow-volume loop graph.
- Uses reference values from the American Thoracic Society(ATS) or another relevant organization.
Obstructive Lung Disease
- A group of diseases causing airway obstruction and airflow restriction.
- Conditions that cause obstructive lung diseases are chronic bronchitis, asthma, emphysema and bronchiectasis
- Characterized by difficulty/inability to exhale air from the lungs.
Obstructive Lung Disease Characteristics
- Problems primarily in expiration.
- Impaired expiratory airflow.
- Impaired carbon dioxide elimination.
- Nonuniform alveolar ventilation.
- Thoracic cage assumes inspiratory position.
- Diaphragm lowers and bulges.
- FVC is normal or decreased.
- FEV1/FVC ratio is decreased.
- FRC is increased.
Obstructive Lung Disease: Flow-Volume Loop
- Concavity in the expiratory limb.
- Reduced FEV1.
- Reduced FEV1/FVC ratio.
Restrictive Lung Disease
- A group of diseases causing decreased lung compliance and reduced lung expansion.
- Characteristics of restrictive lung diseases include various causes, conditions such as intrinsic lung diseases (interstitial lung disease, sarcoidosis, and pneumonitis), and extrinsic lung diseases such as pleural tissue, pleural effusion, pleuritis, neuromuscular disorders, scoliosis, ascites, obesity and abdominal tumors.
- Causes decreased lung elasticity and compliance, hindering full expansion.
Restrictive Lung Disease Characteristics
- Reduced total lung capacity (TLC).
- Reduced lung compliance.
- FVC is reduced.
- FEV1/FVC ratio is normal.
Restrictive Lung Disease: Flow-Volume Loop
- Narrowed loop, relatively higher peak flow.
- Normal looking spirometry; but abnormal flow-volume loop.
- Reduced FVC.
- Relatively high PEF.
- Steep end expiratory phase.
Monitoring Disease Progression
-
Obstructive diseases:
- Weekly FEV1 changes ≥ 12% in healthy subjects or ≥ 20% in COPD patients.
- Yearly changes in FEV1 should not exceed 15%.
-
Restrictive diseases:
- ≥ 10% FVC reduction reflects disease progression.
- Declining FVC is a strong indicator of disease progression in neuromuscular diseases.
How to Interpret Spirometry Results and Reference Values
- Use appropriate reference values (e.g., ATS/ERS 2021).
- Consider patient characteristics (e.g., age, sex, height).
- Understand the normal distribution of healthy lung function data in defining normal range.
Classification of COPD Severity
- Mild (FEV1 ≥ 70% predicted).
- Moderate (FEV1 60-69% predicted).
- Moderate to severe (FEV1 50-59% predicted).
- Severe (FEV1 35-49% predicted).
- Very severe (FEV1 < 35% predicted).
Classification of Restriction Severity
- Normal (≥ 80% predicted).
- Mild (70-79% predicted).
- Moderate (50-69% predicted).
- Severe (<50% predicted).
Pulmonary Function Test Terminologies
- Lung volumes and capacities include:
- Tidal, expiratory reserve volume, inspiratory reserve volume and residual volume.
- Forced expiratory volume (FEV1).
- Forced expiratory volume during 6 seconds (FEV6) ratio.
- Peak expiratory flow (PEF or PEFR or MEF).
- Forced mid-expiratory flow (FEF25-75%)
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Description
This quiz focuses on pulmonary function tests (PFTs) including their purpose, methods, and interpretation. Students will learn to differentiate between various PFTs, especially spirometry, and apply their knowledge in evaluating lung diseases. The quiz aligns with the American Thoracic Society standards for presenting and interpreting spirometry data.
