Pulmonary function tests

Question 1

asthma PFTS

Answer 1

TLC: normal, FEV1/FVC: low, DLCO: normal

Question 2

COPD PFTs

Answer 2

TLC high, FEV1/FVC: low, DLCO: low

Question 3

Interstitial lung dx PFTs

Answer 3

TLC: low, FEV1/FVC: normal, DLCO: low

Question 4

Pulm arterial HTN

Answer 4

TLC: normal, FEV1/FVC: normal DLCO: low

Question 5

Restrictive chest wall dx

Answer 5

TLC: low

FEV1/FVC: normal to increased

DLCO: normal

Caused by: interstitial lung dx, chest wall restriction, neuromuscular disorders

Question 6

PAH has decreased DLCO because

Answer 6

affects small pulmonary arteries and capillaries and see muscularization of small arteries and medial and intimal thickening of muscular arteries leading to decrease in blood flow and diffusion across the capillary bed.

Question 7

ppl with sciolosis and kyphosis will compensate for restrictive dx by

Answer 7

decreasing low tidal volume for increased respiratory rate pts with angles of scoliosis that’s >65 degrees and kyphotic features above T10 will have this.

Question 8

flow volume loop for extrathoracic pulmonary obstruction

Answer 8

Causes of variable EXTRAthoracic obstruction -

vocal cord paralysis or blunted inspiratory side

Question 9

what is normal change in forced vital capacity when standing and lying supine

Answer 9

should see drop in forced vital capacity <10% in supine position as abdominal viscera displace lung tissue in a cephalad direction

Abnormal would be >10% and seen in unilateral diaphragmatic paralysis

Question 10

low forced vital capacity means

Answer 10

restrictive dx

Question 11

difference between obstructive and restrictive PFT

Answer 11

Question 12

BMI>30

pCO2>45

pO2<70

see mild to moderate reduction in FEV1 and FVC and normal FEV1/FVC and DLCO

Answer 12

Obesity hypoventilation syndrome. Obesity l_eads to restrictive lung dx_ and difficulty with chest wall expansion and so see some hypoxemia and some hypercapnia and respiratory acidosis.

This is due to body habitus

Question 13

Asthma vs COPD and late stage COPD

Answer 13

Question 14

Best way to differentiate between asthma and COPD is

Answer 14

reversal of airway obstruction >12% increase in FEV1 with absolute increase in FEV1 of >200 ml in response to bronchodilator therapy.

pts with COPD have partial reversibility but not near complete restoration of normal airflow after bronchodilator administration out of COPD.

Question 15

Residual volume is the

Answer 15

volume of air remaining in the lungs following exhalation and is seen with COPD as being higher due to obstructive air trapping.

Question 16

All flow volume loops

Answer 16

Question 17

Pulmonary physical exam findings

Answer 17

Egophany - ausculation changes from E normally goes to A with consolidation

tactile fremitus - place hands on chest and have them say “ninety nine” or “boy o boy” Normal exam is symmetric and good resonance

consolidation (PNA) - increased tactile fremitus

pleural effusion - decreased tactile fremitus

COPD - decreased tactile fremitis

pneumothorax - decreased tactile fremitis

Question 18

isolated decrease in DLCO but normal FEV1/FVC ratio and normal FEV1. Normal TLC. Pt has been complaining of shortness of breath. Lungs are clear.

Answer 18

Consider pulmonary HTN as this can cause a low isolated DLCO

Question 19

flow volume loop for unilateral mainstem bronchial obstruction

flow volume loop for fixed upper airway obstruction (trachial stenosis)

Answer 19

unilateral mainstem bronchial obstruction - is basically a smaller loop because you lose some of the volume

fixed upper airway obstruction - lose the amount of flow with expiration and inspiration due to narrowed arway (see blunted top and bottom) - focal cord paralysis or goiter.

Question 20

Flow volume loop for variable INTRAthoracic upper airway obstruction

Answer 20

See obstruction below the sternal arch. This could be due to tracheomalacia.

Question 21

PFTs summary:

Answer 21

FVC: forced vital capacity 80-120 is normal

FEV1: forced expiratory volume 80-120 normal

FEV1/FVC - airflow over one second

Restriction FVC<80 and FEV1/FVC >70 (or normal)

Obstruction FVC is normal FEV1/FVC <70

Question 22

Asbestos has

Answer 22

restrictive lung dx

Question 23

pulmonary langerhan cell

Answer 23

low DLCO and generally restrictive disease but can have obstructive if there’s a lot of cysts present

Question 24

sarcoidosis can be

Answer 24

restrictive, obstructive or both