DSA - Pulmonary Function Testing Flashcards
For an __________ disease, air has a hard time moving due to problems in the airways. In some cases (i.e., COPD and emphysema) compliance is high (lungs are stretchable).
Obstructive
For a _________ disease, the compliance is low and the lungs resist inflation.
Restrictive
What is and FEV1/FVC ratio?
Forced Expiratory Volume in 1 second divided by the Forced Vital Capacity
What does a low FEV1/FVC ratio indicate?
Obstructive pattern
What does a normal FEV1/FVC ratio indicate?
Either a restrictive or normal pattern
If the FEV1/FVC is normal, a low FVC value indicates a ________ pattern, while a normal value indicates a ________ pattern.
Restrictive
Normal
Pulmonary function tests are not generally indicated in patients without symptoms, and they may be confusing when nonpulmonary diseases that affect the pulmonary system are active. An example is…
Congestive Heart Failure
Why are pulmonary function tests typically ordered?
- To evaluate symptoms and signs of lung disease
- To assess progression of lung disease
- To monitor the effectiveness of therapy
- To evaluate preoperative patients
- To screen people at risk of pulmonary disease (i.e., smokers)
- To monitor for potentially toxic effects of certain drugs or chemicals
This is the measurement of the air moving in and out of the lungs during various respiratory maneuvers. It allows one to determine how much air can be inhaled and exhaled, and how fast.
Spirometry
What are the three most important lung volume and capacity measures?
FVC
FEV1
FEV1/FVC Ratio
This is the volume of air forcibly expired from a maximum inspiratory effort in the first second.
FEV1 (Forced Expiratory Volume in 1 second)
This is the total volume that can be forcefully expired from a maximum inspiratory effort.
FVC (Forced Vital Capacity)
A spirometric maneuver begins with the patient inhaling as deeply as he or she can. Then the patient exhales as long and as forcefully as possible. The amount exhaled in this manner is the…
FVC
The forced expiratory volume in 1 second (FEV1) is the amount of air exhaled during the first second of the FVC maneuver. It tends to be lower in diseases that obstruct the airway, such as _________ or ________.
Asthma
Emphysema
This is the measure of the ability of the lungs to transfer gas.
Diffusing Capacity
Diffusion in the lungs is most efficient when the ________ _______ for gas transfer is high and the blood is readily able to accept the gas being transferred.
Surface Area
In what instances are diffusion decreased?
– Conditions that minimize the ability of the blood to accept and bind the gas that is diffusing (i.e., Anemia).
– Conditions that decrease the surface area of the alveolar-capillary membrane (i.e., Emphysema, Pulmonary Embolism).
– Conditions that alter the membrane’s permeability or increase its thickness (i.e., Pulmonary Fibrosis).
The gas used to test the diffusing capacity must be more soluble in blood than in lung tissue. Ideally, the amount of gas entering the blood should be limited by the lungs’ ability to transfer it and not by lung perfusion (i.e., the gas must avidly bind to hemoglobin). ________ ________ is the gas used, as it most closely meets those requirements.
Carbon Monoxide
Even after one exhales as long and as hard as possible, some air remains in the lungs. This is called the…
Residual Volume
The Residual Volume plus the plus the FVC equals the…
Total Lung Capacity (TLC)
The Residual Volume, and hence the Total Lung Capacity, cannot be measured by…
Spirometry
For obstructive diseases, measurement of the Residual Volume and Total Lung Capacity can demonstrate _______ _______ and ________.
Air Trapping
Hyperinflation
For restrictive diseases, the _______ _______ _______ is needed to confirm true restriction and better quantitate the degree of restriction.
Total Lung Capacity
Test results are given measured values and as percents of predicted values. The predicted values and lower limits of normal have been determined in population studies of people without physiologic lung impairment. Each patient’s predicted values depend on his or her…
Age
Height
Sex
Criteria for acceptability and reproducibility are established by the American Thoracic Society. In general, an _______ maneuver is acceptable if the patient has made a good effort. An effort is considered good when there is a rapid increase in air flow at the start of exhalation.
FVC
A complete maneuver requires at least 6 seconds of _________ ending with a plateau in flow (i.e., no further air is being blown out).
Exhalation
A flow-time curve and flow-volume loop are usually included with the report to allow one to visualize the rapid rise and the plateau in flow over time and over lung volumes. In a proper _______ maneuver, flow rates should be at their highest near the start of ________ and should decline through the end. This is graphed in the volume-time curve.
FVC
Exhalation
Flow rates are highest near the ________ ________ ________ (where the FVC maneuver begins) and they decline until the ________ ________ (where the FVC maneuver ends). This is graphed as the flow-volume loop.
Total Lung Capacity
Residual Volume
The test is repeated at least three times. To meet reproducibility criteria, all three FEV1 measurements must be within ________ of each other and all three FVC measurements must be within _______ of each other. The test with the greatest sum of the FEV1 and the FVC is reported.
200 mL
200 mL
Spirometry is frequently repeated after giving a _________. If either the FEV1 or the FVC increases by at least 12% and by at least 200 mL from the prior values, then the patient is said to have a significant _________ response.
Bronchodilator
Bronchodilator
To quantify the degree of _________, the clinician needs to note the patients FEV1 as a percentage of the predicted FEV1. Similarly, to quantify the degree of _________, one should note either patient’s FVC or the Total Lung Capacity as a percentage of the respective predicted value.
Obstruction
Restriction
Explain the flow chart starting with “Is the FEV1/FVC ratio less than the lower limit of normal?” and the answer is NO.
You know it is either a restrictive or normal pattern. The next question you should ask is “Is the FVC less than the lower limit of normal?”
If yes = Restrictive pattern – go on to ask if the total lung capacity is known.
If no = Normal spirometry study
Explain the flow chart starting with “Is the FEV1/FVC ratio less than the lower limit of normal?” and the answer is YES.
You know it is an obstructive pattern, and you need to quantitate the obstruction using the FEV1 as a percentage of the predicted value.
The next question you should ask is “Is the FVC less than the lower limit of normal?”
If yes = Ask if we know the total lung capacity.
If no = Pure obstruction
