Basics of Pulmonary Diagnostic Tests

Question 1

Pumonary Function Tests can measure what

Answer 1

Flows

Volumes

Resistance

Compliance

Diffusion capabilities

Question 2

Indication of PFT

Answer 2

• To identify and quantify changes in pulmonary function
  
  • Most common purpose of PFT and will help to differentiate between cardiac and resp source
• Evaluate need and effectiveness of therapy
• ​Epidemiologic Surveillance
• Assess for postoperative pulmonary complications
• Determine pulmonary disability

Question 3

3 Categoires of Pulmonary Function Tests

Answer 3

Measuring dynamic flow rates of gases through the airways

Lung volumes and capacities

Ability of the lungs to diffuse gases

Question 4

Contraindication to PFT

Answer 4

Chest or Abdominal Pain

Recent Surgery of Thorax or Abdomen

Aneurysms

Recent Vascular surgery

Unstable cardiovascular status (myocardial infarction or pulmonary embolus)

Hemoptysis (coughing up blood) of unknown origin

Oral or facial pain exacerbated by a mouthpiece

Presence of acute disease that will interfere wil test

Pneumothorax

Recent eye surgery

Question 5

Why Should a PFT not be done when there is chest or abdominal pain

Answer 5

This is due to the high pressure that are generated in the thorax

Question 6

How Long After a Thorax or Abdomen Surgery can you do a PFT

Answer 6

4-6 weeks

Question 7

ATS PFT Indications

Monitoring

Answer 7

Assess therapeutic intervention

Describe the course of the disease that affect lug function

Monitor people that are exposed injurious agents

Monitor for adverse reactions to drugs with known pulmonary toxicity

Question 8

ATS PFT Indications

Public Health

Answer 8

Epidemiological Surveys

Derivation of reference equations

Clinical research

Question 9

ATS PFT Indications

Disability/Impairment Evaluation

Answer 9

Assess patient as part of rehabilitation programme

Asses risks as part of insurance evaluation

Assess individuals for legal reasons

Question 10

ATS PFT Indications

Diagnostic

Answer 10

Evaluate symptoms, signs, and abnormal lab tests

Measure effect of disease on pulmonary function

Screen individuals at risk of having pulmonary diseases

Assess pre-operative risk

Assess prognosis

Assess health status before beginning strenuous physical activity programmes

Question 11

What is the Primary Problem in Obstructive Diseases

Answer 11

The primary problem is an increase airway resistance (R_aw), which is the difference in pressure between the ends of the airway divided by the flow rate of gas moving through the airway

Question 12

What is the Primary Problem in Restrictive Diseases

Answer 12

The primary problem is a decrease in lung and thoracic compliance and lung volumes

Restrictive lung disease affects the patient where they are unable to fill their lungs on inhalation, as the lungs are restricted from fully expanding resulting in a decrease in volume

Question 13

Types of Obtructive Diseases

Answer 13

CBABE

Cystic Fibrosis

Brochietasis

Asthma

Bronchitis

Emphysema

Question 14

What type of relationship does compliance and volume have

Answer 14

Compliance is the volume of gas per amount of inspiratory effort measured through the amount of pressure created in the lungs or pleural space when inspiratory muscle contract

Question 15

What are the 2 type of PFT equitment

Answer 15

• Those that measure volume
  
  • Volume and flow measuring devices are spirometers
• Those that measure flow
  
  • Flow measuring devices are pneumotachometers

Both types of instruments simultaneously measure time, and compute various volumes and flow rates

Question 16

Capacity

Answer 16

The range or limit of how much a device can measure

Most instruments are designed with capacities to measure volumes and flow rates of all adults.

Question 17

Accuracy

Answer 17

Closeness of agreement between the results of a measurement and the true value

Ex. Calibration with a 3L syringe. If the calibration consistently comes in at it can be said to be accurate

Question 18

Repeatability

Answer 18

Closeness of agreement between the results of successive measurements carried out with the same conditions

Same method, same observer, same instrument, same location, same condition of use, and repeated over a short space of time.

Question 19

Error

Answer 19

No measuring instrument is perfect, and there usually is an arithmetic difference between reference values and measured values and this difference is known as error

Accuracy and error are opposing terms; the greater the accuracy, the smaller is the error.

Accuracy and error are commonly expressed as percentages, with their sum always equaling 100%.

Question 20

Resolution

Answer 20

Smallest detectable measurement

Instruments with high resolution can measure the smallest volumes, flows, and times.

Question 21

Reproducibility

Answer 21

How close the results are from successful measures of the same item under channged conditions

Ex. Checking calibration under slow, medium, and fast flow rates

Question 22

Precision

Answer 22

How often we get the same value on a measure

Question 23

Linearity

Answer 23

Linearity refers to the accuracy of the instrument over its entire range of measurement, or its capacity.

Some devices may accurately measure large volumes or high flow rates but may be less accurate when measuring small volumes or low flow rates.

To determine linearity, accuracy and precision are calculated at different points over the range (capacity) of the device.

Question 24

Output

Answer 24

Output includes the specific measurements made or computed by the instrument.

Question 25

Sensitivity and specificity

Answer 25

Some tests are extremely sensitive,and apparently healthy individuals may have an abnormal test result. However, some tests are not sensitive; individuals must be extremely sick to have an abnormal test result. Most tests of pulmonary function are not specific because several different diseases may cause the test result to be abnormal. This limitation of many pulmonary function tests explains why these tests identify a pattern of impairment rather than diagnose specific diseases.

Question 26

Validity

Answer 26

Validity of the test relates to its meaningfulness or the ability to measure what it is intended to measure. When performing pulmonary function testing, strictly following testing procedures, ensuring patient effort and performance, and ensuring equipment accuracy and calibration establish test validity.

Question 27

Reliability

Answer 27

A reliable test will produce consistent test results with minimal variation In order to check the reliability of a test you need to perform the test more than once Ensuring test validity and reliability is the most important role of the RT.

Question 28

Volume and Flow Monitors

Answer 28

* The term *spirometer* is a generic term for all volume-measuring and flow-measuring devices * Spirometers includes water-sealed, bellows, and dry rolling seal types * A water seal spirometry is more precise than a pneumotachograph * As these devices collect gas they will expand, the magnitude to which the device expands if the measured volumes and the speed of expansion is the flow rate

Question 29

Flow Measuring Devices

Answer 29

* Thermal (hot-wire) anemometer * Measure flow based on temperature drop * Many vents use this * Turbine flowmeter * Pneumotachographs * This is what we will use in PFTs * Pressure differential * Ultrasonic

Question 30

Pneumotachometers

Answer 30

* Flow-measuring devices are commonly called *pneumotachometers* * The Fleisch-type pneumotachometer measures the change in pressure as gas flows through it. * Thermistors or mass flowmeters measure flow through the change in temperature created through gas flowing through it * Tubinometer uses rotation of a fan/blade similar to a windmill

Question 31

Pressure Differential Pneumotachograph

Answer 31

Resistance= (Delta Pressure)/ Flow ## Footnote The gas flow thru these devices is proportional to the pressure drop across a known resistance The resistance can be brass capillary tubes, ceramic with parallel channels, or fine mesh screen Often heated to reduce condensation

Question 32

Hazards/Complications of Spirometry

Answer 32

pneumothorax; increased intracranial pressure; syncope, dizziness, light-headedness; chest pain; paroxysmal coughing; contraction of nosocomial infections; oxygen desaturation due to interruption of oxygen therapy; bronchospasm

Question 33

Patient Position

Answer 33

* It should be reported on whether the patient is sitting or standing during the test * Both positions are allowed but it must be reported so that if testing is performed over long periods of time the same position can be used * Sitting is preferable for safety as there is less of a chance of failing due to syncope * The chair should have arms and no wheels * If a wheelchair is used then make sure the wheels are locked * If the patient is standing then there should be a chair close by

Question 34

What Position is Preferred for Obese Patients

Answer 34

Standing may be preferred for obese patient as larger volumes and flows can be achieved

Question 35

Patient Details

Answer 35

* Should record age, gender, race, height and weight for reference calculation * For patients with deformities (ie. Kyphoscoliosis) the span from middle fingertip to middle fingertip is used as an estimate of height * The use of knee height to predict height can also be used for handicapped people where arm span may be difficult to measure

Question 36

Gas diffusion testing may be helpful in diagnosis diseases such as

Answer 36

Goodpasture’s Syndrome.

Question 37

Medications and Testing

Answer 37

* Should record medications especially cardiac and respiratory medications including the type (oral and inhaled), dose, and when they were last taken * When the test is to determine underlying lung function bronchodilators should be avoided whereas if the purpose of the test is to determine effectiveness of therapy then bronchodilators should be taken as normal

Question 38

Subject Preparation

Answer 38

* Activities to avoid before testing * Smoking within 1 hour of testing * Consuming alcohol within 4hrs of testing * Vigorous exercise within 30 mins of testing * Wearing clothing that substantially restricts full chest and abdominal expansion * Eating a large meal within 2hrs of testing * It should be recorded on the report if any of these factors are a concern * Subjects should be as relaxed as possible before and during the tests. * Dentures should normally be left in place; if they are loose, they may interfere with performance and are, therefore, best removed.

Question 39

What Needs to Be Recorded for Every Test

Answer 39

Temperature, Barometric Pressure, Relative Humidity and time of day are important to record Temperature is an important variable in most pulmonary function tests and is often measured directly by the instrument. This is usually captured during the calibration procedure

Question 40

Repeat Testing

Answer 40

Ideally, when patients return for repeat testing (e.g. at a clinic), the equipment and the operator should be the same, and the time of day should be within 2 h of previous test times.

Question 41

What Are Some Charateristic to Remeber About Testing Order

Answer 41

The measurement of carbon monoxide diffusing capacity of the lung (DL,CO) immediately after a nitrogen washout measurement of the total lung capacity (TLC) will be affected by the increased oxygen content in the lungs, unless enough time has passed to allow the oxygen concentration to return to normal. Tidal breathing manoeuvres may be disturbed by a recently performed maximal forced expiratory manoeuvre. Bronchodilator administration may affect static lung volumes, reducing hyperinflation by up to 0.5 L While bronchodilators do not seem to affect diffusing capacity when measured by the Jones–Meade method, they may allow ,10% of patients to obtain a measurement of diffusing capacity that was not possible pre-bronchodilator

Question 42

Possible Order of Test for PFT

Answer 42

* Dynamic studies * Spirometry * Flow Volume Loop * PEF Static Lung Volume * Inhalation of Bronchodilator * Diffusion Capacity * Repeat Dynamic Studies if Bronchodilators Used

Question 43

Why Should Standard Precautions Be Used

Answer 43

Standard precautions should be applied because of the potential exposure to saliva, mucus, or blood, which can harbor potentially hazardous microorganisms.

Question 44

Transmission can be via direct contact

Answer 44

* There is potential for transmission of upper respiratory diseases, enteric infections and blood-borne infections through direct contact. * Although hepatitis and HIV contagion are unlikely via saliva, transmission becomes a possibility with open sores on the oral mucosa or bleeding gums. * The most likely surfaces for contact are mouthpieces and the immediate proximal surfaces of valves or tubing. * Mouthpieces or pneumotachometers * Saliva, oral mucosa, bleeding gums * Use disposable filters (mouthpieces) and nose clips where possible

Question 45

Transmission can be via indirect contact

Answer 45

Aerosol and droplet There is potential for transmission of tuberculosis (TB), various viral infections, opportunistic infections and nosocomial pneumonia through aerosol droplets. The most likely surfaces for possible contamination by this route are mouthpieces, proximal valves and tubing.

Question 46

Cleaning the Devices

Answer 46

Although it is unnecessary to clean the interior surfaces of the testing instruments routinely between patients,the mouthpiece, nose clips, tubing, and any parts of the instrument that come into direct contact with a patient should be disposed, sterilized, or disinfected between patients. Any equipment surface showing visible condensation from exhaled air should be discarded, disinfected, or sterilized before reuse.

Question 47

What is the most important function of the lungs

Answer 47

Gas Exchange

Question 48

Gas Exchange is Dependant Upon

Answer 48

Diaphragm and thoracic muscles ability to expand thorax and create a sub-atmospheric pressure Unobstructed airway for gas flow Ability for O2 and CO2 to diffuse through the AC membrane Cardiovascular system to circulate oxygenated blood

Question 49

How Long After a C-Section Can You Do a PFT

Answer 49

6-8 Weeks

Question 50

What is an Absolute Contra-Indication for a PFT

Answer 50

Myocardial Infarction within 1 month

Question 51

How Long After a Pneumothorax Can Someone do a PFT

Answer 51

2 weeks post treatment

Question 52

How Long After Eye Surgery Can Someone Do a PFT

Answer 52

Lasik (1 month) Cataract (1-2 months) This is because the change in ocular pressure may be harmful to the eye

Question 53

Respiratory Infection and PFT

Answer 53

* Active TB * Respiratory infection * Airway inflammation can affect results

Question 54

What Happends if a patient has smoked or eaten a large meal before a PFT

Answer 54

Will interfere will forced vital capacity

Question 55

Obstructive Lung Diseases and Airflow

Answer 55

* Obstructive lung diseases conditions make it difficult to exhale air * SOB occurs from the narrowing of the airways in the lungs causing a decrease in flow rates

Question 56

Radius of Airway and Expiration

Answer 56

* As the radius of airways will normally lessen slightly during expiration flow rates are usually measured during expiration

Question 57

Poiseuille’s Law

Answer 57

* It is important to note that according to Poiseuille’s Law a small decrease the radius of the airway will lead to a large increase in airway resistance * Airway resistance can be reduced through contraction of the bronchial and bronchiolar muscles (bronchospasm), excessive secretions, swelling, tumors, collapse of bronchioles, etc.

Question 58

What are We Mesuring When We Measure Flow Rates

Answer 58

* Through measuring flow rates, pulmonary function tests can be used to measure resistance and estimate the size of airways and indicate the presence of obstructive diseases

Question 59

What May Cause a Reduced Lung Compliance

Answer 59

* Alveolar inflammation (pneumonia), swelling (pulmonary edema), scarring (pulmonary fibrosis) * A reduced thoracic compliance: thoracic wall abnormalities (kyphoscoliosis), exogenous pressure exerted on the thoracic cavity (ascites or pregnancy) * Neuromuscular disease as the patient is unable to generate enough sub atmospheric pressure to take a full deep breath

Question 60

Obstructive Vs. Restrictive Disease Useful Measurements

Answer 60

**Obstructive:** Flow Rates **Restrictive:** Volumes or capacities

Question 61

Obstructive Vs. Restrictive Disease Pathology

Answer 61

**Obstructive:** Increased Airway Resistance **Restrictive:** Decreased lung ot thoracic compliance

Question 62

Obstructive Vs. Restrictive Disease Breathing Phase Difficulty

Answer 62

**Obstructive:** Expiration **Restrictive:** Inspiration

Question 63

Obstructive Vs. Restrictive Disease Anatomy Affected

Answer 63

**Obstructive:** Airways **Restrictive:** Lung Parenchyma, Thoracic Pump

Question 64

ATS Equitment and Accuracy

Answer 64

\*According to ATS criteria equipment must have an accuracy of ![]()3% or 0.05L with a flow rate of 0-14 L/sec and Volume of 0.5-8 L

Question 65

Thermal Flowmeters

Answer 65

* Operates on the principle that as gas passes over a heated wire the sensor cools and changes its resistance, and the change in resistance is proportional to gas flow * Gas flow is calculated from the amount of power needed to maintain the temperature of the element (cooling=decreased resistance=higher gas flow) * Inverse relationship between gas flow and power

Question 66

Ultrasonic Pneumotachograph

Answer 66

* **Also called a _Vortex Shedder_!** (ex. Servo-i) * Uses struts to create partial obstruction to gas flow and as gas flows the struts vortices are formed * The ultrasonic transmitter produces sound waves which are interrupted by the vortices * These ‘interruptions’ are counted by the receiver and are equivalent to a specific volume

Question 67

Which Patients are at most risk for infections and which patients are at most hazard

Answer 67

* Patients with oral lesions or active respiratory infections pose the greatest potential hazard, and patients with compromised immune systems are at the greatest risk.

Question 68

Most Likely Equitment to be a source for contamination

Answer 68

* The most likely surfaces for possible contamination by this route are mouthpieces, proximal valves and tubing. * Use disposable filters (mouthpieces) and nose clips where possible

Question 69

Minimum Requirements for Quality Control

Answer 69

* Documentation of repairs or alterations to equipment- * Dates of computer software/hardware updates * Log Volume Calibration and Calibration Checks * Done daily with a 3L syringe * Flow Calibration and Checks * At last 3 maneuvers * Flow between 0.5 – 12 L/s (injection times of 0.5 – 6 sec. with 3L syringe)

Question 70

Which of the following would be considered an indication for performing a pulmonary diagnostic test? 1. To confirm the presence of pulmonary disease 2. To confirm the absence of pulmonary disease 3. To quantify the impact of pulmonary diseases on lung function, if any 4. All of the above 5. A and C

Answer 70

All of the above

Question 71

Pulmonary function studies can assess all of the following except for Carbon Monoxide Levels Lung Volumes Diffusion Capacities Expiratory Flow Rates

Answer 71

Carbon Monoxide Levels

Question 72

You are supposed to perform a full PFT on a patient who underwent abdominal surgery two weeks ago. Is this a contraindication from performing these tests Yes No

Answer 72

Yes

Question 73

The hazards of pulmonary diagnostic testing includes Bronchospasm Fainting Risk of infection Increased intracranial pressure All of the above

Answer 73

All of the above

Question 74

Repeatability is defined as The closeness of agreement between a test result and the true value The closeness of agreement between the results of successive tests under the same conditions The closeness of agreement between the results of successive tests under differing conditions None of the above

Answer 74

The closeness of agreement between the results of successive tests under the same conditions

Question 75

Which of the following activities may impair the reliability of pulmonary function testing? Smoking within 1 hour of testing Drinking alcohol within 4 hours of testing Eating a large meal within 2 hours of testing All of the above A and B

Answer 75

All of the above

Question 76

Patient characteristics that impact lung function includes Height Age Gender All of the Above A and B

Answer 76

All of the Above

Question 77

You would expect less than ideal PFT results from which of the following patients Bill with mild GI upset and pain Tim with recent jaw surgery Betty, pregnant with twins, who suffer from incontinence Millie with Alzheimer’s All of the above

Answer 77

All of the above

Question 78

Ethnicity must be taken in to consideration when assessing PFT results True False

Answer 78

True

Question 79

You are about to test a patient who seem tired and frail. Prior to starting testing you should Ask the patient to stand for better results Ask the patient to sit on a chair with wheel so that he can get close to the device Ask the patient to sit on a chair without wheel so that he is stable Ask the patient if he would like to reschedule his tests

Answer 79

Ask the patient to sit on a chair without wheel so that he is stable