DSA: Pulmonary Function Test

Question 1

what are indications for pulmonary fxn testing

Answer 1

1. symptoms and signs of lung disease
2. progression of lung disease
3. monitor effectiveness of therapy
4. evaluate preoperative pts
5. screen ppl at risk of pul disease
6. monitor for potentially toxic effects (drugs or chemicals)

Question 2

what is FVC

Answer 2

forced vital capacity

total volume that can be forcefully expired from a maximum inspiratory effort

Question 3

What is FEV1

Answer 3

forced expiratory volume in 1 second

Question 4

what can you determine with FEV1/FVC ratio

Answer 4

determine if there is obstruction, restriction or normal

normally close to 1

< 0.7 –> obstructive lung disease

normal/elevated ==> restrictive disease,

Question 5

what is diffusing capacity

Answer 5

measure ability of lungs to transfer gas

-most efficient when SA is high and blood is readily bale to accept gas

Question 6

when can diffusing capacity be reduced

Answer 6

minimize ability of blood to accept and bind gas (anemia)

decreased SA - (emphysema, pul embolism)

conditions that alter membrane permeability/increase thickness (fibrosis)

Question 7

RV + FVC =

Answer 7

TLC

Question 8

what does obstructive disease demonstrate

Answer 8

RV and TLC demonstrates air trapping and hyperinflation

Question 9

What is the FVC maneuver

Answer 9

measure effort

=good when rapid increase in air flow at start of exhalation

-requires at least 6 secs of exhalation ending w/ plateu in flow

Question 10

If a patient has an obstructive pattern and their FVC is not less than the lower limit of normal, what type of obstruction does the patient have?

Answer 10

pure obstruction

If FVC is lower, total lung capacity helps further differentiate

Question 11

If the patient has a normal FEV1/FVC ratio and the FVC is less than the lower limit, what type of pattern does the patient have?

Answer 11

restrictive pattern

total lung capacity will help further differentiate

Question 12

What is present if FVC is less than lower limit of normal and the FEV1/FVC ratio is low

Answer 12

mixed pattern w both obstructive & restrictive component (TLC decreased))

or

obstruction is very severe - led to significant air trapping (TLC increased/normal & RV sig increased)

Question 13

what are extraparenchymal causes of restriction

Answer 13

obesity

neuromuscular disease

chest wall deformities

large pleural effusion

Question 14

what are pulmonary parenchymal causes of restriction

Answer 14

pulmonary fibrosis

Question 15

what is seen w/ anemia

Answer 15

normal FVC, TLC

• number of Hb reduced - decrease ability of lungs to transfer CO
• lower diffusing capacity

Question 16

what is suggested if DLCO is less than low limits of normal after lung volume adjustment, hemoglobin or both

Answer 16

parenchymal disease