PFTs

Question 1

what kind of information can you obtain from PFTs?

Answer 1

• how much air volume can be moved in and out of the lungs
• how fast the air in the lungs can be moved in and out
• how stiff the lungs and the chest are
• the diffusion characteristics of the membrane through which the gas moves
• measurement of how the lungs have responded to tx

Question 2

Indications for PFTs

Answer 2

• screening for lung disease
• following progression of disease
• evaluating effectiveness of therapy
• evaluating before surgery
• assessment of impairment or disability.

Question 3

What are they types of PFTs?

Answer 3

• spirometry
• peak flow
• measurement of lung volumes (body box)
• quantification of diffusion capacity
• oxygen uptake –exercise capacity

Question 4

Spirometry

• measures what?
• what graphic illustration does this provide?

Answer 4

• Forced expiratory volume in 1 second (FEV1)
• Forced Vital Capacity (FVC)
• Flow Volume Loop

Question 5

list some examples of obstructive disease?

Answer 5

• asthma
• bronchitis
• excessive mucus plugging
• foreign object inhalation
• invasive tumors
• COPD

Question 6

Can TLC be measured by spirometry?

Answer 6

-no, because air remains in the lungs at the end of maximal exhalation.

Question 7

A decrease in lung volumes means what kind of lung disease?

Answer 7

restrictive

Question 8

How do you measure Total Lung Capacity?

Answer 8

• Helium dilution
• Nitrogen Washout
• Body plethysmography (gold standard)
• Chest radiograph or HRCT

Question 9

What are some examples of restricitve disorders?

Answer 9

Neuromuscular:

• malnutrition
• paralysis of diaphragm
• Myasthenia Gravis
• Muscular dystrophy
• Poliomyelitis
• ALS

Intrinsic Disorders:

• Sarcoidosis
• TB
• Pneuomonectomy
• Pneumonia

Question 10

What is:

• FEV1
• FVC
• FEF

Answer 10

FEV1: forced expiratory volume in 1 sec

FVC: forced vital capacity (volume of air that can be maximally forcefully exhaled)

FEF 25-75%: average forced expiratory flow during the mid portion of the FVC.

Question 11

what test is sensitive for early obstructive airway disease?

Answer 11

FEF 25-75%

Question 12

what is PEFR?

Answer 12

-the peak expiratory flow rate during expiration, it is the measure of the highest expiratory flow rate during PFT test.

Question 13

Define:

• TLC
• VC
• TV
• RV

Answer 13

TLC: volume in lungs at maximal inspiration

VC: maximum volume expired after a maximum inspiration

TV: the volume inspired and expired during normal breathing

RV: volume left in the lungs after maximal expiration

Question 14

What is the normal and abnormal range of values for FVC and FEV1

Answer 14

FVC and FEV1 are over 80% of predicted values.

Abnormal if they are below 70%

Question 15

what would you expect the FEV1/FVC ratio to be with obstructive & restrictive disease?

WHat would you expect to flow volume curve to look like?

Answer 15

FEV1/FVC for obstructive disease is less than 70%

FEV1/FVC for restrictive disease is greater than 70%

CURVE:
obstructive- concave, descends more quickly than normal, sharp point

restrictive- smaller version of normal flow.

Question 16

Bronchoprovocation Challenge:

• when do you perform this test?
• how does this work?
• what is a positive test value?

Answer 16

When do you perform this:

• pt who has sx of asthma, but has normal PFTs and no response to bronchodilator therapy
• patient who experiences sx not usually associated with asthma
• those who require screening tests for asthma such as scuba divers, military ppl.

How does it work:

• pre test spirometry for baseline reading
• give pt an irritant(methacholine) to try to induce bronchoconstriction, repeat spirometry 30 and 90 seconds afterwards

Positive Test value:
-decrease of 20% in FEV1

Question 17

Who cannot have a bronchoprovocation challenge??

Answer 17

• unstable cardiac dz
• MI in last three mo
• Stroke in last 3 mo
• uncontrolled HTN
• significant bronchospasm already present
• prenancy/nursing

Question 18

Bronchodilators

• what can this test determine?
• if the patient improves 2 of their FVC, FEV1, and FEF 25-75% tests what does this mean?
• What are the improvement standards? (indicating the dz is reversible)

Answer 18

• determines reversibility of airway obstruction
• if two of three measurements improve then the pt has a reversible airway obstruction that is responsive to medication.
• require FEV1 or FVC to increase more than 12% AND more than 200mL in adults or just 12% increase in ages 5-18.

Question 19

WIth restrictive lung disease both FEV1 and FVC present with normal or increased FEV1/FVC ratio, true or false?

Answer 19

True!!!

Question 20

Explain the expected FEV1, FEV, FEV1/FVC for someone with restrictive and obstructive disease.

Answer 20

Obstructive: 
FEV1: decreased
FVC: decreased 
FEV1/FVC: decreased. 
*ratio less than  70% 

Restrictive: 
FEV1: decreased
FVC: decreased
FEV1/FVC: increased or normal
*Ratio greater than 70%

Question 21

Diffusion Capacity (DLCO)
-useful test for?

Answer 21

Useful:

• determining the degree of emphysema in smokers
• differentiating chronic bronchitis from emphysema in smokers
• restrictive disease differentiating interstitial lung disease from restrictive etiologies of disease
• recurrent PE
• Pulmonary HTN
• Disability measurement.

Question 22

How does DLCO work?

Answer 22

• inhale CO and helium
• hold breath for 10 seconds and then exhale quickly
• obtain measurement.
• smoking lowers DLCO
• CO preferred in this test because its not normally present in alveoli/blood and avidly binds to Hgb

Question 23

What do the results of DLCO mean? Which disease is associated?

Answer 23

Low DLCO with obstruction: emphysema or CF in kids

Low DLCO with restriction: pulmonary fibrosis or hypersensitivity pneumonitis

High DLCO: Asthma, polycythemia

Question 24

VO2 Testing

-what does this determine?

Answer 24

• determines how efficient the cardio-resp system is together. (according to jeN)
• determines patients functional exercise capacity
• the ability of a person to take in, transport, and use oxygen.