Diagnostics: PFT Flashcards Preview

ICM -- Pulmonology > Diagnostics: PFT > Flashcards

Flashcards in Diagnostics: PFT Deck (44):
1

Most accurate measure of Pulmonary fxn

Pleth Box

2

Signs of Air Trapping/Pseudorespiration

Decreased FVC, Increased TLC

3

Three types of pulmonary fxn testing?

Spirometry Lung Volumes Diffusing Capacity

4

Types of Spirometry tests

Methacholine Cronchodilator Challenge Neuromuscular Protocol

5

Types of Lung Volume Tests

Helium dilution Nitrogen washout Plethysmography

6

Why do PFTs?

Explain Dyspnea, hypoxemia Objectively Follow Disease Pre-Op Exams

7

Total Lung Capacity =

Inspir. Reserve + Tidal + Expiratory Reserve + Residual

8

Vital Capacity =

Insp. Reserve + Tidal + Exp. Reserve

9

Functional Residual Capacity =

Expiratory Reserve Vol + Residual Vol.

10

What do patients do in spirometry?

Maximal breath to TLC, then blows out as hard/fast as possible

11

Name for total volume expired in a spirometry test

Forced Vital Capacity

12

Name of the volume expired in the first second of a spirometry test?

FEV1

13

Most reproducible measure of flow rate over time

FEV1

14

In PFTing curves, the portion above the axis is _______ and the portion below the axis is ______

Exhalation Inhalation

15

Criteria for an acceptable PFT?

Smooth, Continuous curve Good Start Finish w/ plateau for 1 sec

16

Obstructive pattern should make you suspect...

Asthma, emphysema, Chronic Bronchitis

17

Restrictive pattern of PFT should make you suspect...

Pulm. fibrosis, Hypersensitivity pneumonitis, sarcoidosis, silicosis, neuromuscular probs

18

What happens in an extrathoracic resp probs

Closure on insp. Opening on expiration (Flat on bottom of loop) Example -- Laryngeal Cancer, Vocal Cord Adduction

19

What happens in intrathoracic resp probs

Open on inspiration, Closure on expiration (Flat on top, normal curve below)

20

If no confidence intervals are given, what is the cutoff for diagnosing an obstruction?

70% FEV1/FVC Look for a scooped loop

21

With an FEV1/FVC ration below 70%, you determine the patient has an obstructive disease. They have a normal FVC. What do you assess next?

Post-dilator FEV1 and FVC. If Albuterol fixes it, its Asthma. If not, its COPD

22

How do you distinguish which type of COPD you have?

DLCO Down in emphysema Normal in Chronic bronchitis

23

How do you determine is a restrictive lung disease patient has a parenchymal or extrapulmonary restriction?

DLCO Down in parenchymal Normal in extrapulmonary

24

Sign of a positive bronchodilator change

FEV1 or FVC increase of 12% AND absolute chance of 200 mL after bronchodilaton

25

In mathacholine testing, a FEV1 drop of ______ at a low concentration is diagnostic of hyperresponsiveness

more than 20%

26

Neuromuscular disease presents as...

Restriction

27

What do you do in neuromuscular testing

Assess resp. muscle strength (make patient forcibly inhale/exhale against a closed mouthpiece attached to a pressure gauge).

28

Normal Max Inspiratory Pressure? Expiratory?

Insp. -- 65 Expiratory -- 80

29

Normal Maximal Voluntary Ventillation

Normal is FEV1 x 35

30

How does a Helium Dilution test work?

Known volume of inert gas (He) at a known concentration is inhaled. Gas is diluted by air volume already in lungs. Concentration of exhaled gas is measured, reflects the initial volume of gas in the lungs.

31

How does a Nitrogen Washout test work?

Put a person on 100% Oxygen, measure the amount of Nitrogen being released with their breaths over time.

32

What happens in plethysmography?

Subject makes an inspiratory effort against a closed airway, which increased the volume of the lung. Airway pressure decreases and the box pressure increases. Use P1V1=P2V2

33

Volume measured by He dilutiona nd Nitrogen washout?

Functional Volume Does NOT measure areas with Trapped Gas Inaccurate in severe obstructive lung disease

34

What are you learning in a DLCO test?

The amoutn of gas that is able to diffuse across the alveolar-capillary membrane

35

How do you measure diffusing capacity?

Inhale known conc. of CO + Helium to TLC. Hold breath for 10 seconds Exhale and measure the CO and Helium in expired gas

36

Main determinants of diffusing capacity?

Surface Area Capillary Flow Membrane Diffusing Capacity (kCO)

37

DLCO =

KCO X VA

38

In a patient with normal lung volumes and spirometry, a low DLCO indicates...

Pulmonary vascular disorder.

39

Interpret

Q image thumb

Normal PFT

40

Interpret

Q image thumb

PFT Obstructive

41

Intrepret

Q image thumb

PFT - Restrictive

42

Fixed, Variable Extrathoracic, or Variable Intrathoracic?

Q image thumb

Fixed

43

Fixed, Variable Extrathoracic, or Variable Intrathoracic?

Q image thumb

Variabe Extrathoracic

44

Fixed, Variable Extrathoracic, or Variable Intrathoracic?

Q image thumb

Variable Intrathoracic