PFT Flashcards
A PFT is a useful tool for
Guiding management of patients with diagnosed lung diseases
A PFT is the primary diagnostic tool for evaluating and treating patients
Respiratory symptoms
Guiding management of patients with diagnosed lung diseases
What sign or symptoms would cause a physician to order a PFT?
Dyspnea
Intermittent wheezing
Monitor treatment response after lung disease is diagnosed
What are the pulmonary function categories that can be evaluated using a PFT?
Lung volumes and capacities
Expiratory flow rate and volume
Pulmonary diffusion capacity
Respiratory muscle strength
What is a PFT capable of detecting?
Airflow limitation
Restriction of lung volumes
Impaired gas transfer
Respiratory muscle weakness
What are PFTs used for in regards to treatment?
Efficacy
T/F: the use of filters negates the need to regularly clean and disinfect equipment
False
What are PFTs used for in regards to disease processes?
Monitoring of disease progression
What measures should be taken to control infection when administering a PFT?
Universal precautions
N95s if patient has airborne illness
Wear gloves when handling contaminated equipment
Use disposable mouthpieces or flow sensors between patients
Before administering a PFT, what kinds of things should you ask a patient regarding their pulmonary history?
History of pulmonary diseases
Tobacco exposure
Current medications
Cough
Allergies
Chest surgeries
Occupational exposures
Why is it important that patients withhold taking their respiratory medications prior to taking a PFT?
Because the medication can change the outcome of the PFT results
Before taking a PFT, how long should a patient stop taking LABAs?
12 hours
Before taking a PFT, how long should a patient stop taking albuterol?
4 hours
BEfore taking a PFT, how long should a patient stop taking slow release methylxanthines?
24 hours
Before taking a PFT, how long should a patient stop taking ipratropium for?
4 hours
Before taking a PFT, how long should a patient stop taking tiotropium for?
24 hours
Before taking a PFT, how long should a patient stop taking inhaled steroids for?
Maintain dosage
What are the steps involved in administering a PFT when checking pre and post bronchodilator results?
Ensure patient has not taken bronchodilator prior to test
Obtain 3 acceptable baseline FCV maneuvers
Administer bronchodilator
Wait at least 10 minutes
Repeat FVC, obtain 3 acceptable results
Compare pre and post bronchodilator FVC and FEV1
What dosage of bronchodilator does the american thoracic society recommend in order to ensure a full patient response?
4 separate 100 mg doses of albuterol delivered by MDI with spacer
When does weight affect the outcome of a PFT?
When their BMI is above 30
Can act as a restrictive mechanism
What is the most important measurement to get from a patient prior to taking a PFT?
Height
IF a patient does not know their height or their height cannot be accurately measured, how can you determine their height?
Wingspan = fingertip to fingertip
Describe the lung volumes of african americans, asians, and east indians in comparison to “normal” values
Typically 12% smaller
What are the 3 phases of the spirometry test?
Deep inhalation
Blast air out
Keep blowing until empty
Why is race considered when performing a PFT?
Different races have different lung volumes
How long does a proper FVC test take?
6 seconds
No more than ____ FVC maneuvers should be attempted
8
What occurrences would invalidate a PFT?
Slow start
A cough in the 1st second
Early termination
A valsalva maneuver
A leak
An obstructed mouthpiece
Evidence of an extra breath
If you are performing a PFT on a patient and notice a difference of __________ between the largest and next largest FVC/FEV1, the test must be repeated
0.150 liters or less
What are common spirometry errors?
Failure to take a full breath
A hesitating start
Failure to BLAST out the air
Stopping to soon
By measuring a patients volumes, we are looking for evidence of a
Restrictive disorder
Define tidal volume
Volume of gas inhaled or exhaled during normal breathing
Define inspiratory reserve volume
Maximum volume of gas that can be inspired from the end of a normal inspiration
Define expiratory reserve volume
Maximum volume of gas that can be expired from the end of a resting expiration
Define residual volume
Volume of gas remaining in the lungs after a maximal expiration
Define vital capacity
Maximum volume of gas that can be exhaled from the lungs after a maximal inspiration or inhaled from a point of maximal exhalation
Define inspiratory capacity
Maximum volume of gas that can be inspired from the normal end expiratory position
hat pulmonary study function values can be obtained from a flow volume loop?
FVC
FEV1
FEF(25-75%)
PEFR
PIFR
Define total lung capacity
Volume of gas in the lungs at the end of a maximal inspiration
When is a flow loop produced?
When a patient inhales rapidly to measure Forced inspiratory vital capacity AFTER exhaling rapidly for 6 seconds
Define functional residual capacity
Volume of gas remaining in the the lungs at the end of a resting expiration
Describe FEV1
The volume of air exhaled in the first second of exhalation
What diseases would decrease the FEV1?
Obstructive diseases
What pulmonary study function values are used to assess reversibility of disease condition?
FVC, FEV1, FEF(25-75%)
What change in FVC is required to determine whether or not a bronchodilator was effective?
FVC > 10%
What change in FEV1 is required to determine whether or not a bronchodilator was effective?
A change in FEV1 > 200 ml or 12%
What change in FEF(25-75%) is required to determine whether or not a bronchodilator was effective?
FEF(25-75) > 20-30%
How is the severity of COPD measured?
Based off of the FEV1/FVC ratio
A patient with mild COPD would have an FEV1 of…
70-80% of predicted
A patient with moderate COPD would have an FEV1 of
60-69% of predicted
A patient with very severe COPD would have a FEV1 of
<35% of predicted
A patient with moderate severe COPD would have an FEV1 of
50-59% of predicted
A patient with severe COPD would have an FEV1 of
35-49% of predicted
What is the FEV1/FVC ratio?
Volume of air expired in the first second expressed as a percent of FVC
What does a reduced FVC with a normal FEV1/FVC ratio indicate?
Restriction
What does a decreased FEV1/FVC ratio indicate?
Airflow obstruction
Describe FEF 25-75%
Mean expiratory flow during the middle half of the FVC maneuver
What does the FEF 25-75% represent?
Reflects flow through later emptying airways
In a restrictive disease process, what would the FVC look like?
Decreased
In a restrictive disease process, what would the FEV1 look like?
Decreased
Potentially increased in certain disease states due to increased elasticity recoil of the lungs
In a restrictive disease process, what would the FEF 25-75% look like?
Normal or increased
In a restrictive disease process, what would the FEV1/FVC look like?
Normal or increased
In a restrictive disease process, what would the TLC look like?
Decreased
In an obstructive disease process, what would the FVC look like?
Normal or decreased
In an obstructive disease process, what would the FEV1 look like?
Decreased
In an obstructive disease process, what would the FEF 25-75% look like?
Decreased
In an obstructive disease process, what would the FEV1/FVC look like?
Decreased
In an obstructive disease process, what would the TLC look like?
Normal or increased
How are restrictive disorders characterized?
Reduced lung volumes
Decreased lung compliance
What are obstructive disorders characterized by?
Limitation of expiratory airflow so that the airways cannot empty as rapidly compared to normal
What are some examples of restrictive disorders?
Interstitial fibrosis
Scoliosis
Obesity
Lung resection
Neuromuscular disease
Cystic fibrosis
What are obstructive disorders characterized by?
Limitation of expiratory airflow so that the airways cannot empty as rapidly compared to normal
What are examples of obstructive disorders?
Asthma
COPD
Cystic fibrosis
How many BPM should a patient performing an MVV target?
90 bpm
Describe maximum voluntary ventilation (MVV)
The largest volume of air that a patient can movie in and out of the lungs in a 12 second interval
How are patients instructed to breath during a MVV test?
As rapidly and deeply as possibly
The variability between MVV efforts should not exceed….
20%
How many acceptable efforts should be recorded for an MVV?
2
MVV tests can isolate what disease processes?
Vocal cord dysfunction
Tracheal stenosis
Which patient population would Peak expiratory flow monitors be useful for in every day life?
Asthmatics
Describe PEFR
Maximum flow rate achieved during FVC maneuver
WHat is a potential problem with PEFR readings?
They are dependent on patient effort \
What is considered the green zone for patients with asthma in regards to PEFR?
80-100% of personal best
What is considered the yellow zone for patients with asthma in regards to PEFR?
50-80% of personal best
What is considered the red zone for patients with asthma in regards to PEFR?
<50%
What is the DLco test?
Dlco measures the ability of the lungs to transfer gas from the inhaled air to the red blood cells in pulmonary capillaries
Describe how a DLco could help differentiate between a chest wall cause of restriction vs a interstitial lung disease
In a chest wall constriction, the DLco would be normal
In ILD, the DLco would be decreased
How would a DLco help determine whether or not a patient is suffering from emphysema or asthma/simple bronchitis?
Emphysema = decreased DLco
Asthma/bronchitis = normal DLco
What would the DLco of a patient with normal spirometry who complains of dyspnea and suffers from either pulmonary vascular disease or mild ILD present?
Low DLco
T/F: A DLco can be a useful tool in determining disease progression in in patients with ILD
True
Describe how the DLco test is performed
Patient wears nose clip and breaths through flanged rubber mouth piece connect to a spirometer circuit
Patient takes several large breaths and is then instructed to exhale to RV
Patient rapidly and fully inhales gas with 0.3% CO and inert gas tracer
Patient holds breath for 10 seconds and then exhales for 10 seconds
How can a DLco be utilized in patients with systemic diseases?
To determine if there is pulmonary involvement
How can DLco be utilized in cancer treatment?
To determine if radiation, chemotherapy or other drugs are inducing pulmonary dysfunction
What factors affect an individual’s ability to facilitate gas exchange in their lungs
Surface area of membrane
Thickness of membrane
Hemoglobin and blood flow in capillaries
Matching of ventilation and perfusion
A normal result on a DLco is…..
80-120% of predicted
Predicted what??
Describe the 6 minute walk test
Simple exercise test to measure the functional status of patients with COPD
Why is the 6 minute walk test preferred to FEV1 in patients capable of performing it?
The 6 minute walk test has been shown in several studies to independently predict mortality in COPD patients and to be a better predictor of motality that FEV1
How far should healthy people be able to walk in 6 minutes?
400-700 meters
How far should patients with mild COPD be able to walk in 6 minutes?
> 350 meters
How far should patients with moderate COPD be able to walk in 6 minutes?
250-349 meters
How far should patients with severe COPD be able to walk in 6 minutes?
150-249 meters
How far can patients with very severe COPD walk in 6 minutes?
<149 meters
