Trachte: Tests of Pulmonary Function Flashcards
A low lung volume, reduced max flow rate and normal FEV1/FVC is indicative of what disease?
Restritive disease
How does obstructive lung disease affect lung volume FEV1/FVC and flow rate?
HIGH lung volume
REDUCED FEV1/FVC
REDUCED max flow rate
What decreases FEV1?
REDUCED by INCREASED airway resistance and DECREASED elastic recoil of the lung
What is FEV1 limited by?
Dynamic compression of the airways
How do you measure FRC?
He dilution
N2 washout
How do you measure diffusion?
CO disappearance
How do you measure pulmonary blood flow?
Fick principle
How do you measure ventilation perfusion relationships?
Radioactive xenon
How do you measure the inequality of ventilation perfusion rates?
A-a gradient (alveolar to arterial gradient)
What should an A-a gradient typically be?
4 mmHg
How do you measure compliance?
Have a subject swallow an esophageal pressure transducer and measure pressure changes corresponding to exhaled volume
How do you measure airway resistance?
body plethysmograph while measuring air flow
How does a body plethysmograph work?
Inspiration causes pressure change in the box>
can calculate the change in alveolar pressure from the change in volume
How do you measure closing volume? How does it work?
N washout
Maximal inhalation of 100% oxygen and maximal exhalation
What are the four phases of N2 measurement?
- Pure dead space (flat w/ no N2)
- Mixture of dead space and alveolar ventilation (rising)
- Pure alveolar ventilation (flat w/ 30-40% N2)
- Spike in N2 concentration at END of expiration (signals CLOSING of airways at base of lung)