Respiratory Tests

Question 1

Pulmonary Function tests (PFT’s) look at how:

Answer 1

much air lungs can hold
quickly air can move in and out of lungs
well the lungs put oxygen into and remove carbon dioxide from the blood

Question 2

To determine respiratory values, how many tests are used?

Answer 2

Multiple tests required to determine all values

Question 3

Some tests may be repeated after using……

Answer 3

Some of the tests may be repeated after using medication (used after a bronchodilator)

Question 4

The air in the lung is divided in how many compartments? What are they? what do they measure?

Answer 4

Tidal volume (TV): (normal respiration)
- air exhaled during normal respiration

Inspiratory Reserve Volume (IRV):
- maximum air inhaled above TV

Expiratory Reserve Volume (ERV):
- maximum air exhaled below the tidal volume

Residual Volume (RV):
- volume of air remaining in the lungs after maximal expiration

Question 5

The sum of all 4 compartments is……

Answer 5

TOTAL LUNG CAPACITY

Question 6

How many lung capacities are there? What do they measure?

Answer 6

Total Lung Capacity (TLC):
- The sum of all 4 compartments or volumes
total volume of air in the lungs at maximal inspiration (VC +RV)

Functional Residual Capacity (FRC):
volume of air in the lungs at the end of normal expiration

Vital Capacity (VC):
- total volume of air exhaled after a maximal inhalation

Question 7

What is the FEV1? What does it measure?

Answer 7

Forced Expiratory Volume in 1 Second

Patient inspires to TLC and exhales maximally. The volume of air exhaled in the first second = FEV 1

Best measure for assessing severity of airflow obstruction

Question 8

What is FVC? What does it measure?

Answer 8

Forced Vital Capacity

• Total volume of air expired as rapidly as possible from TLC

Question 9

What is the difference between obstructive and restrictive lung disease?

Answer 9

Obstructive lung diseases include conditions that make it hard to exhale all the air in your lungs. People with restrictive lung disease have trouble fully expanding their lungs with air.

Question 10

What is the FEV1/FVC ratio? What is considered a healthy FEV1? Asthma vs. COPD?

Answer 10

Helps to differentiate restrictive from obstructive lung disease (% of total volume of air)

The FEV1 is usually expressed as a % of the total volume of air exhaled and is reported as the FEV1/FVC ratio.

A FEV1 of 80% is normal.

FEV1 is lower in obstructive lung diseases and normal to only a little lower in restrictive lung diseases

In asthma, after bronchidilator, FEv1 improves whereas COPD it does not.

Question 11

What are some other PFT’s commonly used?

Answer 11

Spirometry (Best test of pulmoary function)
Peak Expiratory Flow Meter
Carbon Monoxide Diffusing Capacity (DLCO)

Question 12

What is spirometry? Uses?

Answer 12

Uses a spirometer to objectively assess an individual’s pulmonary performance

Uses:
Diagnosing lung disease & assessing severity
Measuring the effect of a disease on lung function
Monitoring the course of disease or result of therapeutic intervention
Assessing surgical risk
Assessing prognosis for pulmonary conditions
Pre-employment screening and surveillance of employees at risk for occupational lung diseases
Assessing the potential effects of environmental lung disease

Question 13

Who should perform a spirometry test?

Answer 13

Should be conducted by trained personal where there is a quality assurance program

Question 14

Basic procedure of spirometry test?

Answer 14

In general, the patient is asked to take the deepest breath they can, and then exhale into the sensor as hard as possible, for as long as possible, preferably at least 6 seconds.

Question 15

What is measured by spirometry?

Answer 15

FVC
FEV1
FEV1/FVC ratio

Question 16

Most accurate PFT?

Answer 16

Spirometry

Question 17

What are the results of spirometry compared too?

Answer 17

“Predicted normal” (based on height, weight, race, age and sex)

Patient’s “Personal Best” lung function

Question 18

Limitations of spirometry?

Answer 18

Requires full cooperation of the patient

Question 19

Contraindications of spirometry?

Answer 19

Increases intracranial or intraocular pressure (brain surgery, concussion, eye surgery)
Increases in intra-thoracic and intra-abdominal pressure (surgery)
Increases in mycardial demand or changes in bp (severe hypertension, significant arrthymias)
Risk of infection (active TB, hameophilus)

Question 20

What populations is spirometry not conducted in?

Answer 20

Do not do spirometry under age of 6, elderly, dementia, language barriers

Question 21

Define obstructive lung disease? FEV1/FEC Ratio?

Answer 21

The inability to get air out of the lung
FEV1/FVC Ratio: Decreased

Question 22

Define Restrictive Lung Disease? FEV1/FEC Ratio?

Answer 22

The inability to get air into the lung and maintain normal lung volumes
Decreased air in all divisions (i.e. interstitial lung disease, myasthenia gravis, mechanical conditions)
FVC that is low, FEV1 may or may not be low
Ratio: Normal or increased

Question 23

Spirometry bronchodilator challenege is used to determine…..

Answer 23

REVERSIBILITY

Question 24

Determining reversibility of airway obstruction can be performed using spiromnetry. How? Use?

Answer 24

PFTs are repeated 10-15 minutes after administration of an inhaled 2 agonist (eg., Salbutamol). This determines if a reversible component to the airway obstruction exists.

An ↑ of FEV1 of 12% (>0.2L in adults) after an inhaled agonists = acute bronchodilator response (reversibility check)

Patient should withhold regular medications prior to testing

If you did not see reversibility, than COPD (progressive disease)
Asthma is reversible
Best way to differentiate asthma and COPD

Question 25

What is Peak Expiratory Flow Rate? Counselling, use, FEV1 compartibility?

Answer 25

Measured with a portable peak flow meter
Maximal flow rate that can be produced during forced expiration (L/min, L/sec)
Results are compared to “personal best” or to “predicted values”
Changes in PEF generally parallel those of the FEV1, however it is less reproducible

Required maximum patient effort for accuracy
PATIENT EDUCATION is impt for proper technique
Intended for patient self-monitoring once diagnosis established

Question 26

What is carbon monixe diffusing capacity (DLco) testing? Methods? Uses?

Answer 26

Measurement of the ability of carbon monoxide to diffuse across the alveolar-capillary membrane (gas exchange)

Two methods:
Single breath or breath-holding method
Steady state method

Will be reduced in all clinical situations where gas transfer from the alveoli to capillary blood is impaired (late stages of COPD)

Question 27

What is pulse oximetry?

Answer 27

Utilizes light absorptive characteristics of hemoglobin and the pulsating nature of blood to aid in determining oxygenation status

Question 28

Define Arterial Blood Gas Test. Use?

Answer 28

An essential function of the lungs is to maintain blood gas homeostasis (oxygenation and ventilation)

ABG’s reflect how well lungs are oxygenating the blood and are useful to assess acid-base status
Useful for monitoring critically ill patients, monitoring effectiveness of therapy, titrate oxygen flow rates, assess patient for home oxygen

Question 29

What is an acid? Example?

Answer 29

Any substance with a pH < 7.0. eg., CO2

Question 30

What is a base? Example?

Answer 30

Any substance with a pH > 7.0. eg., HCO3 (Bicarb)

Question 31

What is PaCO2?

Answer 31

Pressure or tension exerted by dissolved CO2 gas in the blood (CO2 is combined with hemoglobin & transported to the alveolar capillaries where it is released)

Question 32

What is PaO2?

Answer 32

Indicates the level of oxygenation of arterial blood

Question 33

Define metabolic in acid-base balance?

Answer 33

refers to a disorder from an alteration in HCO3- (influenced by the kidneys)

Question 34

Define respiratory in acid-base balance?

Answer 34

refers to a disorder from an alteration in CO2 (influenced by the lungs)

Question 35

What is the anion gap formula?

Answer 35

AG = Na+ - (Cl- + HCO3-)
Normal range: 3-11 mmol/L
If elevated = metabolic acidosis (use as a side check, can be elevated in other conditions)

NO INFORMATION ABOUT RESPIRATORY

Question 36

Time Range of Compensation

Answer 36

Time frame (respiration compensation happens very quickly, metabolic is slower (may take days))
Respiratory compensation – Lungs
Metabolic compensation – Kidneys (will release bicarb in blood if respiratory acidosis)

Question 37

Normal ph indications:

Answer 37

pH<7.35 = acidosis
pH>7.45 = alkalosis

Question 38

O2 Saturation Normal Value

Answer 38

≥ 95%

Question 39

What is a bronchoscopy?

Answer 39

An endoscopic technique of visualizing the airways
The bronchoscope is inserted through the nose or mouth (or tracheostomy)
Tissue and/or fluid samples can be taken if needed

Can be used diagnostically or therapeutically