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Questions and Answers
Peak Expiratory ______ Rate is defined as the maximum flowrate achieved during a forced expiratory maneuver.
Peak Expiratory ______ Rate is defined as the maximum flowrate achieved during a forced expiratory maneuver.
Flow
A typical value for Peak Expiratory Flowrate is 10 L/sec or ______ L/minute.
A typical value for Peak Expiratory Flowrate is 10 L/sec or ______ L/minute.
600
Peak flow readings that are consistently decreasing may be caused by fatigue and the patient does not have mild ______ disease.
Peak flow readings that are consistently decreasing may be caused by fatigue and the patient does not have mild ______ disease.
restrictive
Forced Expiratory Flow 200-1200 is defined as the average flowrate that occurs during a forced expiratory maneuver after the first ______ mL has been expired.
Forced Expiratory Flow 200-1200 is defined as the average flowrate that occurs during a forced expiratory maneuver after the first ______ mL has been expired.
Values for FEF 200-1200 are decreased with mechanical problems in the airways (i.e. tumors) and ______ disease.
Values for FEF 200-1200 are decreased with mechanical problems in the airways (i.e. tumors) and ______ disease.
Forced Expiratory Flow 25%-75% measures flow within the ______ airways.
Forced Expiratory Flow 25%-75% measures flow within the ______ airways.
The Forced Expiratory Flow between 25% and 75% (FEF25-75) may be decreased if FVC and FEV are greatly increased in the post-______ study.
The Forced Expiratory Flow between 25% and 75% (FEF25-75) may be decreased if FVC and FEV are greatly increased in the post-______ study.
Forced Expiratory Volume/Time (FEV_T) is defined as the ______ of gas expired over a given time interval in seconds.
Forced Expiratory Volume/Time (FEV_T) is defined as the ______ of gas expired over a given time interval in seconds.
The FEV______is considered to be the only value needed to diagnose obstructive disease.
The FEV______is considered to be the only value needed to diagnose obstructive disease.
FEV1.0 is also used to assess the degree of improvement after ______ administration.
FEV1.0 is also used to assess the degree of improvement after ______ administration.
FEV1/FVC% expresses the forced expiratory volume for a given time interval as a ______ of the vital capacity.
FEV1/FVC% expresses the forced expiratory volume for a given time interval as a ______ of the vital capacity.
A minimum acceptable value for FEV1.0/FVC% is ______%.
A minimum acceptable value for FEV1.0/FVC% is ______%.
Decreased FEV1/FVC% is associated with ______ disease.
Decreased FEV1/FVC% is associated with ______ disease.
Maximum Voluntary ______ is defined as the largest volume of air inhaled and exhaled over a 12 second period.
Maximum Voluntary ______ is defined as the largest volume of air inhaled and exhaled over a 12 second period.
The value for Maximum Voluntary Ventilation test is then extrapolated to 1 minute and reported in liters per ______, corrected to BTPS.
The value for Maximum Voluntary Ventilation test is then extrapolated to 1 minute and reported in liters per ______, corrected to BTPS.
A typical value for Maximum Voluntary Ventilation is ______ L/min.
A typical value for Maximum Voluntary Ventilation is ______ L/min.
The Maximum Voluntary Ventilation provides information about the status of the ______ muscles.
The Maximum Voluntary Ventilation provides information about the status of the ______ muscles.
The FVC maneuver involves a forced expiratory vital capacity maneuver followed by a forced ______ vital capacity maneuver.
The FVC maneuver involves a forced expiratory vital capacity maneuver followed by a forced ______ vital capacity maneuver.
On a flow-volume loop, volume is displayed ______ (side-to-side) and flow is displayed vertically (up and down).
On a flow-volume loop, volume is displayed ______ (side-to-side) and flow is displayed vertically (up and down).
______ is measured with the patient starting at Total Lung Capacity during the FVC maneuver.
______ is measured with the patient starting at Total Lung Capacity during the FVC maneuver.
______ is measured with the patient starting at Residual Volume during the FVC maneuver.
______ is measured with the patient starting at Residual Volume during the FVC maneuver.
In the assessment of flow-volume loops, ______ represents a decrease in lung volumes while maintaining normal flowrates, leading to a tall, skinny loop appearance.
In the assessment of flow-volume loops, ______ represents a decrease in lung volumes while maintaining normal flowrates, leading to a tall, skinny loop appearance.
In the context of flow-volume loops, ______ is represented by a 'scooped out' portion on the expiratory part of the loop, indicating increased resistance in the small airways.
In the context of flow-volume loops, ______ is represented by a 'scooped out' portion on the expiratory part of the loop, indicating increased resistance in the small airways.
Reduced flows evident on both inspiration and expiration that are approximately equal characterize ______ airway obstruction on a flow-volume loop.
Reduced flows evident on both inspiration and expiration that are approximately equal characterize ______ airway obstruction on a flow-volume loop.
In the context of flow-volume loops, decreased flows on expiration, along with normal inspiratory flows, suggest a(n) ______ intrathoracic obstruction.
In the context of flow-volume loops, decreased flows on expiration, along with normal inspiratory flows, suggest a(n) ______ intrathoracic obstruction.
In the context of flow-volume loops, decreased flows on inspiration, along with normal expiratory flows, suggest a ______ extrathoracic obstruction.
In the context of flow-volume loops, decreased flows on inspiration, along with normal expiratory flows, suggest a ______ extrathoracic obstruction.
All measured PFT values are compared to the ______ values for that individual patient.
All measured PFT values are compared to the ______ values for that individual patient.
Predicted PFT values are primarily based on the patient's age, height, ______, ethnic origin, and weight/body surface area.
Predicted PFT values are primarily based on the patient's age, height, ______, ethnic origin, and weight/body surface area.
In PFT interpretation, the measured value is divided by the predicted value to obtain a(n) ______ predicted.
In PFT interpretation, the measured value is divided by the predicted value to obtain a(n) ______ predicted.
A patient's PFT predicted value that is greater than or equal to 80% is considered ______.
A patient's PFT predicted value that is greater than or equal to 80% is considered ______.
A patient's PFT predicted value that is less than 80% but greater than 70% is labeled as mild ______.
A patient's PFT predicted value that is less than 80% but greater than 70% is labeled as mild ______.
A patient's PFT predicted value that is less than 70% but greater than 60% is labeled as ______.
A patient's PFT predicted value that is less than 70% but greater than 60% is labeled as ______.
A patient's PFT predicted value that is less than 60% but greater than 50% is labeled as moderate/______.
A patient's PFT predicted value that is less than 60% but greater than 50% is labeled as moderate/______.
A patient's PFT predicted value that is less than 35% is labeled as very ______.
A patient's PFT predicted value that is less than 35% is labeled as very ______.
To estimate patient effort during a Maximum Voluntary Ventilation, multiply the patient's FEV by ______.
To estimate patient effort during a Maximum Voluntary Ventilation, multiply the patient's FEV by ______.
If a patient has a low tidal volume and a fast respiratory rate during the MVV procedure, this indicates ______ lung disease.
If a patient has a low tidal volume and a fast respiratory rate during the MVV procedure, this indicates ______ lung disease.
Variable ______ obstruction appears as normal expiratory flows with decreased inspiratory flows.
Variable ______ obstruction appears as normal expiratory flows with decreased inspiratory flows.
Variable ______ obstruction is characterized by normal inspiratory flows with decreased expiratory flows.
Variable ______ obstruction is characterized by normal inspiratory flows with decreased expiratory flows.
If the MVV is 55% of predicted with a normal FEV1, this may be an indication that the patient gave a ______ effort.
If the MVV is 55% of predicted with a normal FEV1, this may be an indication that the patient gave a ______ effort.
The best application for measuring gross changes in airway function before and after bronchodilator administration is ______.
The best application for measuring gross changes in airway function before and after bronchodilator administration is ______.
A recorder plots flow against ______ for both inspiratory and expiratory maneuvers in a flow-volume loop.
A recorder plots flow against ______ for both inspiratory and expiratory maneuvers in a flow-volume loop.
The flows referred to as FEF25%, FEF50%, and FEF75% are more sensitive in detecting early small ______ obstruction than FEV1.
The flows referred to as FEF25%, FEF50%, and FEF75% are more sensitive in detecting early small ______ obstruction than FEV1.
To estimate patient effort, multiply the patient's FEV1 by 35; if the MVV is less than that value, suspect ______ patient effort.
To estimate patient effort, multiply the patient's FEV1 by 35; if the MVV is less than that value, suspect ______ patient effort.
In the context of PFT interpretation, predicted values are primarily based on a patient's age, height, gender/sex, ethnic origin and ______ or body surface area.
In the context of PFT interpretation, predicted values are primarily based on a patient's age, height, gender/sex, ethnic origin and ______ or body surface area.
Flashcards
What is Peak Expiratory Flow (PEF) or Peak Expiratory Flowrate (PEFR)?
What is Peak Expiratory Flow (PEF) or Peak Expiratory Flowrate (PEFR)?
Maximum flow rate achieved during a forced expiratory maneuver.
What is Forced Expiratory Flow 200-1200 (FEF200-1200)?
What is Forced Expiratory Flow 200-1200 (FEF200-1200)?
The average flowrate during a forced expiratory maneuver after the first 200 mL has been expired.
What is Forced Expiratory Flow 25%-75% (FEF25%-75%)?
What is Forced Expiratory Flow 25%-75% (FEF25%-75%)?
Average flow rate during the middle half of a forced expiratory maneuver.
What is Forced Expiratory Volume/Time (FEVT)?
What is Forced Expiratory Volume/Time (FEVT)?
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What is FEV1/FVC%?
What is FEV1/FVC%?
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What does a decreased FEV1/FVC% indicate?
What does a decreased FEV1/FVC% indicate?
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What is Maximum Voluntary Ventilation (MVV)?
What is Maximum Voluntary Ventilation (MVV)?
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What information does MVV provide?
What information does MVV provide?
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What does fixed airway obstruction look like on a flow volume loop?
What does fixed airway obstruction look like on a flow volume loop?
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What does variable extrathoracic obstruction look like on a flow volume loop?
What does variable extrathoracic obstruction look like on a flow volume loop?
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What does variable intrathoracic obstruction look like on a flow volume loop?
What does variable intrathoracic obstruction look like on a flow volume loop?
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What does restriction look like on a flow volume loop?
What does restriction look like on a flow volume loop?
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What does asthma look like on a flow volume loop?
What does asthma look like on a flow volume loop?
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What does Emphysema look like on a flow volume loop?
What does Emphysema look like on a flow volume loop?
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What is Maximum Forced Expiratory Flow (FEF max)?
What is Maximum Forced Expiratory Flow (FEF max)?
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What factors are PFT values based on?
What factors are PFT values based on?
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Study Notes
Flows
- PEFR (Peak Expiratory Flow Rate)
- FEF200-1200 (Forced Expiratory Flow)
- FEF25-75 (Forced Expiratory Flow)
- FEVT (Forced Expiratory Volume/Time)
- FEV1/FVC % (Forced Expiratory Volume/Time/Forced Vital Capacity Ratio)
Peak Expiratory Flow Rate (PEFR)
- This is the maximum flow rate achieved during forced expiration.
- PEFR is measured in liters/second or liters/minute ATPS corrected to BTPS
- A typical value is 10 L/sec or 600 L/minute.
- PEFR is nonspecific in terms of diagnosis and is highly dependent on patient effort.
- It serves as an indicator of patient effort.
- A portable Wright peak flow meter is available for measurement.
- It effectively monitors asthmatic patients or measures changes in airway function upon bronchodilator administration.
- Decreasing peak flow readings may stem from fatigue or mild restrictive disease.
Forced Expiratory Flow 200-1200 (FEF200-1200)
- It represents the average flow rate during forced expiration after the initial 200 mL is expired.
- FEF200-1200 is measured in liters/second ATPS corrected to BTPS.
- A typical value is 6 L/sec.
- FEF200-1200 measures airflow within the large airways.
- Decreased values could indicate mechanical issues in the airways or obstructive disease.
- Poor patient effort during the FVC maneuver can also decrease values.
Forced Expiratory Flow 25%-75%
- The average flowrate during the middle half of a forced expiratory maneuver.
- Measured in liters/second ATPS corrected to BTPS.
- Typical value is 4–5 L/sec
- It measures flow within the small airways.
- It is considered the most sensitive test for detecting the presence of early small airway disease.
- It measures flow within the small airways and is decreased with obstructive disease.
- FEF25%-75% may appear erroneously decreased if FVC and FEV, are greatly increased in the post-bronchodilator study.
Forced Expiratory Volume/Time (FEVT)
- It measures the volume of gas expired over a given time interval in seconds.
- The most common FEVT measurements are FEV0.5, FEV1.0, FEV2.0, FEV3.0, and FEV6.0.
- FEV1.0 is the only value needed to diagnose obstructive disease.
- FEVT is measured in liters ATPS with the subscript indicating the time interval, corrected to BTPS.
- Decreased flows signify obstructive disease, especially FEV1.0.
- FEV1.0 also assesses improvement after bronchodilator administration.
- A 10–15-minute wait is needed after administering a bronchodilator before retesting.
FEV1/FVC%
- The forced expiratory volume for a certain time interval, expressed as a percentage of vital capacity
- Minimum acceptable values: FEV0.5/FVC% = 60%, FEV1.0/FVC% = 70%, FEV2.0/FVC% = 94%, FEV3.0/FVC% = 97%, and FEV6.0/FVC% = 99%.
- Decreased values indicate obstructive disease.
- Normal values may indicate restrictive disease, even if VC and/or FEV1 are decreased.
- To calculate FEV1/FVC% from a graph: Calculate the FVC, calculate FEV1, then divide FEV1 by FVC before multiplying by 100: FEV1/ FVC = 3.0/5.0 = 60%
Maximum Voluntary Ventilation (MVV)
- The largest volume of air inhaled and exhaled over a 12-second (minimum) period.
- The value is extrapolated to 1 minute and reported in liters per minute, corrected to BTPS.
- The typical value is 170 L/min.
- It provides information about the status of respiratory muscles, lung/thorax compliance, and airway resistance.
- Technique: Breathe deeply and rapidly into a spirometer for at least 12 seconds without panting.
- Formula: Number of breaths × volume × 5 = L/min; for example, 9 breaths × 1 L × 5 = 45 L/min.
- Temperature correction is need: 45 L/min × temperature correction factor = 50 L/min.
- While performing the MVV with the Collins (water-seal) spirometer, position the bell mid-position to allow full inhalation and exhalation.
- Significance: Significant value reductions indicate severe obstructive disease dependent on patient effort.
- To estimate patient effort, multiply the patient's FEV1 by 35; an MVV less than that value suggests poor effort.
- Troubleshooting: Poor effort indicated if MVV is 55% of predicted with normal FEV1. Restrictive lung disease is indicated by low tidal volume combined with rapid respiratory rate while performing MVV.
FVC for Flow-Volume Loop
- Definition: A forced expiratory vital capacity maneuver followed by a forced inspiratory vital capacity maneuver.
- A recorder plots the flow against the volume for inspiratory and expiratory maneuvers.
- Volume is displayed horizontally, flow vertically on the flow-volume loop.
- Expiration is above the baseline, inspiration is below.
- When instructing the patient, emphasize maximal inspiration and forced, rapid, exhalation without coughing.
- PEF measured with the patient starting at TLC, PIF measured at RV.
Flow/Volume Loop
- The flows are termed FEF25%, FEF50%, and FEF75%
- The percentage denotes the VC's exhaled amount.
- FEF25%, FEF50%, and FEF75% are the maximum flowrates after respectively exhaling 25%, 50%, and 75% of vital capacity.
- Decreases in FEF50% and FEF75% may be indicative of obstructive disease.
- FEF50% correlates with FEF25%-75% in diagnosing early small airways disease.
- The values for FEF25%, FEF50%, and FEF75% can be more sensitive in detecting early small airway obstruction than the FEV1.
- Maximum Forced Expiratory Flow (FEF max): the highest flow on the expiratory curve, much like the peak expiratory.
Evaluating Airway Obstruction (Flow Volume Loop)
- If the obstruction is in the upper airway, trachea, or mainstem bronchi, FEF50% helps locate it.
- Fixed airway obstruction: when decreased FEF50% and FIF50% has roughly equal values. e.g. Tracheal stenosis.
- Variable extrathoracic obstruction: appears as normal expiratory flows with decreased inspiratory flows. e.g. Vocal cord paralysis
- The FEF50%/FIF50% ratio is increased to greater than 1.2.
- Variable intrathoracic obstruction is the opposite, normal inspiratory flows with diminished expiratory flows.e.g. Tumor near the carina.
- The FEF50%/FIF50% ratio is then decreased with a ratio under 0.8.
- The shape of the Flow-Volume Loop is diagnostic for certain diseases or conditions.
- Restriction - Decreased lung volumes with normal flow rates result in a tall, skinny loop.
- Asthma - Increased resistance in small airways causes a decrease in expiratory flows, resulting in a "scooped out" portion on the expiratory part of the flow/volume loop.
- Emphysema - Increased small airway resistance alongside loss of elastic recoil leads to reduction of expiratory flows, yielding a more pronounced "scooped out" appearance than with asthma.
- Fixed large airway obstruction - Reduced flows evidence on both phases of inspiration and expiration that are also equally equal.
- Variable intrathoracic obstruction - Decreased expiratory flows alongside normal inspiratory flows.
- Variable extrathoracic obstruction - Decreased inspiratory flows alongside normal expiratory flows.
- Poor effort produces inconsistent patterns
Interpretation of PFT Data
- Measured PFT values are compared to predicted values for each patient - Predicted values are based on age, height, gender/sex, ethnic origin, and weight/body surface area (HAGR).
- To get a % predicted, divide the measured value by the predicted value.
- % Predicted values: ≥ 80% is normal, < 80% is mild dysfunction, < 70% is moderate, < 60% is moderate/severe, < 50% is severe, < 35% is very severe.
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