Pulmonary Function Tests Flashcards
What are some of the indications for doing pulmonary function testing?
Patient presents with possible pulmonary disease
Monitor patients with known pulmonary disease
Investigation in diseased patients with possible respiratory complications
Pre-op evaluation
Evaluation of patients at risk of lung disease
Surveillance following lung transplant
One of the indications for performing PFTs is investigation of patients with presentation suggesting pulmonary disease. What symptoms might these patients present with, prompting you to perform pulmonary function testing?
Cough Wheezing Breathlessness Crackles Abnormal chest X ray
One of the indications for performing PFTs is to monitor patients with known pulmonary disease to track progression or response to treatment. What are some conditions that require monitoring with PFTs?
Interstitial fibrosis
COPD
Asthma
Pulmonary vascular disease
One of the indications for performing PFTs is investigation of patients with disease that may have respiratory complications. What are a couple examples of disease that may have respiratory complications?
Connective tissue disorders
Neuromuscular disorders
One of the indications for performing PFTs is for pre-op evaluation. What are some types of operations require PFTs in pre-op?
Lung resection
Abdominal surgery
Cardiothoracic surgery
One of the indications for performing PFTs is to evaluate patients at risk of lung disease. This may be done if a patient is exposed to what types of things?
Pulmonary toxins like radiation, medication, or environmental or occupational exposure
One of the indications for performing PFTs is surveillance following lung transplant. What are these PFTs assessing for?
Acute rejection
Infection
Obliterative bronchiolitis
What are some contraindications for performing PFTs?
Myocardial infarction within the last month Unstable angina Recent thoracoabdominal surgery Recent ophthalmic surgery Thoracic or abdominal aneurysm Current pneumothorax
T/F: active respiratory infections like tuberculosis are absolute contraindications to performing pulmonary function testing
False: patients with active infections such as Tb are not precluded from having PFTs, but they should be deferred until risk of cross contamination is negligable
What position is the patient recommended to be in for PFTs?
Seated; if standing there is risk of syncope
[however they can be performed standing]
What are the recommendations in terms of smoking, eating, and clothing prior to pulmonary function testing?
Patient advised not to smoke for 1 hour prior
No large meals 2 hours prior
No restrictive clothing
How many times should PFTs be performed in order to ensure reproducibility?
3x with less than 200 mL variation
What are the 3 primary pulmonary function tests?
Spirometry
Flow volume curves
Peak expiratory flow rate
How does spirometry work?
Patient takes maximal inspiration and forcefull expels as long a they can, as quickly as they can
[called the forced vital capacity maneuver]
What measurements are obtained with spirometry?
FEV1
FVC
FEV1:FVC ratio
[spirometry measures volume against time]
What does the patient do to obtain a reading for flow volume curve PFT?
Patient performs maximal inspiratory maneuver followed by max expiratory effort
Flow volume curves show a positive ________ limb, and a negative _________ limb.
A. Inspiratory; expiratory
B. Inspiratory; inspiratory
C. Expiratory; inspiratory
D. Expiratory; expiratory
C. Expiratory; inspiratory
The max flow rate during expiration during the flow volume curve PFT can be measured as the _____ ______ _____ rate
Peak expiratory flow
What are some other PFTs that are less common than the spirometry, flow volume curve, and peak expiratory flow rate?
Static lung volume
Bronchodilator testing
Diffusion capacity
Static lung volumes cannot be measured via spirometry. What are some methods for measuring static lung volumes?
Whole body plethysmography in airtight body box
Nitrogen washout
Helium dilution
What is the purpose of diffusion capacity PFT?
Gives information about the integrity and size of alveolar blood membranes
It measures the diffusion of gas across the alveolar membrane which is determined by the surface area and integrity of alveolar membrane and pulmonary vascular bed
What type of lung disease causes a limitation in flow rate and is the more common type?
Obstructive
Describe intrathoracic airway obstruction
Upper part of lumen has greater pressure than intrathoracic pressure
Almost always due to tumor in major airway, often caused by smoking
Describe variable extrathoracic obstruction
Occurs outside pleural reflection; creates positive intrathoracic pressure. Pressure is also positive in lumen of airway.
Often due to vocal cord tumors or vocal cord spasm/muscle dysfunction
What are some examples of obstructive lung diseases?
COPD Chronic bronchitis Emphysema Asthma Bronchiectasis
A patient presents to your clinic with shortness of breath. You perform pulmonary function testing and the only abnormal finding is a reduction in expiratory reserve volume. What is your likely diagnosis?
Obesity
A patient presents to your clinic with shortness of breath. You perform pulmonary function testing and the only abnormal finding is a reduction in diffusion capacity. You run some further tests but cannot determine any other obvious respiratory cause. What is your likely diagnosis?
Pulmonary embolism
What effect does obstructive lung disease have on the FEV1:VC ratio determined by spirometry?
Decreased
Obstructive lung disease causes a loss of elastic recoil and radial support. What changes might you see on the flow volume loop in a patient with COPD?
Concave appearance to desscending portion of expiratory limb (rather than straight line)
The flow volume loop may appear normal in a patient with asthma, except for which value?
Peak expiratory flow rate will be reduced
A patient presents to your clinic with shortness of breath. You run some basic PFTs and find some flattening of the expiratory limb while the inspiratory limb appears normal. What is your likely diagnosis?
A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease
B. Intrathoracic obstruction
A patient presents to your clinic with shortness of breath. You run some basic PFTs and find that the expiratory limb has a convex appearance on their flow volume loop. In addition, they have a low vital capacity but a normal FEV1:VC ratio. What is your likely diagnosis?
A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease
D. Restrictive pulmonary disease
What change occurs in the total lung capacity with restrictive pulmonary disease?
Decrease
What changes occur in the total lung capacity and diffusion capacity in a patient with obstructive pulmonary disease?
TLC increase
Diminished diffusion capacity
A patient presents to your clinic with shortness of breath. You run some basic PFTs and find symmetric flattening of both the inspiratory and expiratory limbs on their flow volume loop. What is your likely diagnosis?
A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease
C. Fixed extrathoracic obstruction
