PFT’s

Question 1

Purpose of PFT

Answer 1

Diagnosis symptomatic disease (most common)
-chronic dyspnea/couch, hypercapnia, Hypoxemia
Screening for asymptomatic disease (high risk)
Prognosis of known disease
Monitor response to treatment

Question 2

Obstructive lung diseases

Answer 2

COPD, asthma, bronchiectasis, cystic fibrosis

Question 3

Restrictive lung diseases

Answer 3

Interstitial lung disease (pulmonary fibrosis)
Chest wall pathology (scoliosis)
Obesity
Neuromuscular disease

Question 4

Pulmonary vascular disease

Answer 4

Pulmonary HTN
Chronic thromboembolic disease

Question 5

Functions of the pulmonary systems tested by PFT’s

Answer 5

Airways
Parenchyma (alveoli, interstitium)
Pulmonary vasculature
Bellow/pump mechanism (chest wall, diaphragm)
Neural control of ventilation

Question 6

Standard PFT’s

Answer 6

Spirometry - diagnose obstructive disease
Lung volumes - diagnose restrictive disease
Diffuse capacity of carbon monoxide - suggest possible pulmonary vasculature disease

Question 7

Specialized PFT’s

Answer 7

ABG’s
Exercise oximetry
6MWT
Peak flow
Max ins/exp pressure

Question 8

Tidal volume

Answer 8

Air in/out in normal breathe

Question 9

Inspiratory Reserve Volume

Answer 9

Amt of volume inhaled above normal TV

Question 10

Expiratory Reserve Volume

Answer 10

Amt exhaled beyond normal TV

Question 11

Residual volume

Answer 11

Air left after max exhale

Question 12

Inspiratory capacity

Answer 12

TV + IRV

Question 13

Functional Reserve Capacity

Answer 13

ERV + RV

Question 14

vital capacity

Answer 14

TV + IRV + ERV

Question 15

Total lung capacity

Answer 15

TV + IRV + ERV + RV

Question 16

Spirometry (function and values measured)

Answer 16

Technique used to measure airflow and some lung volumes

Measures:
-FEV1
-FVC (forced vital capacity)
-FEV1/FVC ratio
-flow volume loop

Also:
-Peak Expiratory Flow Rate (max slope of curve- change in volume/change in time)
-FEF25-75
-max voluntary ventilation

Question 17

Flow volume loop

Answer 17

Graph of airflow as a function of volume

Question 18

Interpretation of FEV1 and FVC in obstructive disease

Answer 18

FEV1: normal (mild) or decreased (mod/severe)
FVC: normal (mild/mod) or decreased (severe)
FEV1/FVC ratio: decreased; <70%

Question 19

Interpretation of FEV1, FVC in Restrictive Disease

Answer 19

FEV1: normal or decreased
FVC: decreased
FEV1/FVC ratio: normal or increased; > 70%

Question 20

Interpretation of Flow Volume Loop in mildly obstructive disease

Answer 20

PEFR mildly reduced
Coving of slope
Decreased FEF25-75
Late plateau/FVC preserved

Question 21

Interpretation of flow volume loop on severe obstructive disease

Answer 21

PEFR severely decreased
Increased amount of coving of slope
FVC reduced/no plateau

Question 22

Interpretation of flow volume loop in restrictive disease

Answer 22

PEFR normal or mildly reduced
No coving of slope
FVC reduced/normal plateau

Question 23

COPD Stages based off FEV1

Answer 23

Stage 1: > or equal to 80%
Stage 2: 50-80%
Stage 3: 30-50%
Stage 4: <30%

Question 24

Why are high concentrations of carbon monoxide dangerous?

Answer 24

Highly soluble in blood
High affinity for Hb
Normally absent in lungs or blood in large amts

Question 25

DLCO

Answer 25

Volume or carbon monoxide diffused per min per unit of pressure Measures overall function of alveolar capillary membrane thru fick’s law of diffusion <40% predicted value -> severe impairment

Question 26

conditions that decrease DLCO

Answer 26

Decreased membrane surface area (emphysema) increase membrane thickness (ILD) Pulmonary HTN Anemia

Question 27

Conditions that increase DLCO

Answer 27

Exercise Supine position Asthma Pulmonary hemorrhage Polycythemia Mild LHF (increases L side pressure, increase pulmonary blood volume)

Question 28

Primary indications for measuring DLCO

Answer 28

-Categorize pt w/ restrictive disease as either probable ILD vs extra-thoracic restriction -identify early ILD in high risk patients -quantify emphysema in pts w/ COPD