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Flashcards in PFTs -Goya Deck (11):
1

What is spirometry measuring? What is it used for?

-measures volume or flow as a pt inhales or exhales
--> FVC (forced vital capacity), FEV1 (forced expiratory volume in 1 second) and ratio FEV1/FVC

-good for detecting and quantifying pulmonary impairment (specific diagnoses cannot be made with spirometry alone) --> classify as normal, obstruction or restriction
-monitoring response to therapy

2

What does a FEV1/FVC ratio of less than 70% indicate?

obstructive ventilatory defect

3

How is severity determined in obstructive defects?

Mild: FEV1 > 70%

Moderate: 60-69%

Moderately Severe: 50-59 %

Severe: 35-49%

Very Severe: < 35%

4

What test should be done for a new obstructive defect?

Bronchodilator Response

short acting beta agonist given in 4 separate doses --> improvement in FEV1 or FVC of 12% or more =+ response

5

What is the shape of the expiration on a flow-volume curve for an obstructive defect?

concave
--> airway collapses as the pt exhales

6

What does an FVC < 80% suggest? What else should be done to confirm this diagnosis?

restrictive defect is suggested

need to obtain lung volumes of confirm diagnosis!

TLC 120% =obstructive

7

What does the DLCO depend on?

-intact alveolar-capillary membrane

-hemoglobin concentration

-CO

--> measures the ability of the lungs to transport inhaled gas from alveoli to pulmonary capillaries

8

What could a decreased DLCO (<80%) indicate?

Obstructive Lung Disease

Parenchymal Lung Disease

Pulmonary Vascular Disease

Anemia

9

Can you diagnose restrictive lung diseases based on spirometry?

NO!

need lung volumes

10

If the TLC is >80% but the FVC is <80%, does the pt have a restrictive defect?

NO!

11

When is DLCO beneficial?

differentiating asthma (should have normal DLCO) from emphysema

evaluate restrictive lung disease

evaluate CV disease