PFT

Question 1

what is the purpose of PFT

Answer 1

• Identify and quantify changes in pulmonary function die to disease
• evaluate effectiveness of therapy
• perform epidemiological surveillance for pulmonary disease
• assess patients for risk of postoperative complications

Question 2

primary abnormality for Obstructive disease

Answer 2

increased airway resistance

Question 3

primary abnormality for restrictive disease

Answer 3

decreased lung volumes or lung compliance or both

Question 4

PFT equipment

Answer 4

spirometer- used to measure lung volumes
pneumotachometer- used to measure flow
Every measuring device has capacity, accuracy, error, resolution, precision, linearity, & output

Question 5

what are the 3 principles of measurements ?

Answer 5

1. ) performing spirometry to measure airway mechanics 2.) measuring lung volumes and capacities
2. )measuring diffusion capacity of lungs

Question 6

what is the FVC maneuver

Answer 6

-most common test of pulmonary mechanics
- deep inhalation with force exhalation
- is dependent on pt cooperation
pt must performed 3 times in order to be acceptable

Question 7

FEV1

Question 8

FEV1/FVC

Answer 8

reduced with obstructive disease
normal with restrictive disease
should at least 70%

Question 9

reversibility

Answer 9

If obstruction is present, reversibility must be evaluated
Done by performing spirometry before & after therapy
Bronchodilator is administered by small-volume nebulizer or MDI
Reversibility indicates effective therapy
Reversibility is defined as 12% or greater improvement in FEV1 & at least 200-ml increase in FEV1

Question 10

techniques for measuring RV

Answer 10

Helium dilution - known amount of helium will be diluted by size of pt's residual volume. 
nitrogen washout 
79% of RV is nitrogen 
volume of N exhaled divided 0.79= RV
body box - follows Boyle's law

Question 11

TLC normal values

Answer 11

about 6 L

Question 12

normal VC

Answer 12

4.8 L, depends on age, gender, height and ethnicity

Question 13

definition upper airway obstruction

Answer 13

defined as any obstruction from the carina up to the external orifices
extra thoracic- vocal chords to mouth.
intra thoracic- vocal chords to carina

Question 14

Extrathoracic obstruction

Answer 14

(vocal chords to mouth)

- flow is reduced during inspiration, flow is normal during expiration.

Question 15

Intrathoracic obstruction

Answer 15

vocal chords to the carina

inhalation is normal, expiration flow is decreased