Pulmonary function testing Flashcards
what are the indications to perform PFTs (5)? what is the overall goal?
- eval of patients with suspected respiratory disease
- eval of severity of respiratory disease
- pre op eval
- eval of persons at risk for pulmonary disease (smokers, occupational)
- assessment of response to therapeutic interventions
obtain baseline function
VC = ?
ERV + tidal volume + IRV
or, ERV + inspiratory capacity
inspiratory capacity = ?
tidal volume + IRV
ERV + tidal volume + IRV
or, ERV + inspiratory capacity
vital capacity
tidal volume + IRV
inspiratory capacity
functional residual capacity = ?
ERV + residual volume
ERV + residual volume = ?
functional residual capacity
vital capacity + residual volume = ?
total lung capacity
total lung capacity
vital capacity + residual volume = ?
what does spirometry measure?
dynamic measurement of AIR FLOW (obstruction)
what does body plethysmography measure?
static measurement for lung volumes (restriction)
what does diffusion capacity of the lungs for CO measure?
gas exhange capacity evaluation
can spirometry be used to measure restrictive lung diseases?
NO
what ratio is referenced to determine if there is an obstruction to air flow?
FEV1 / FVC
what value is observed when determining how severe an obstruction is?
FEV1
what indicates severe obstruction on PFT?
FEV1 is 50% compared to reference population
flow-volume pattern: obstructive
reduced peak flow, scooped-out mid-curve
flow-volume pattern: severe obstructive
steeple pattern, reduced peak flow, rapid fall off
flow-volume pattern: restrictive
normal shape, normal peak flow, reduced volume
reduced peak flow, scooped-out mid-curve
description of obstructive flow volume pattern
steeple pattern, reduced peak flow, rapid fall off
description of severe obstructive flow volume pattern
normal shape, normal peak flow, reduced volume
description of restrictive flow volume pattern
flow-time pattern: obstructive
slow rise, reduced volume expired, prolonged time to full expiration
flow-time pattern: restrictive
fast rise to plateau at reduced max volume
slow rise, reduced volume expired, prolonged time to full expiration
flow-time pattern: obstructive
fast rise to plateau at reduced max volume
flow-time pattern: restrictive
bronchoprovocation test: indication
to evaluate airway hyperrespnosiveness
what is a positive bronchoprovocation test?
FEV1 decreases by 20%
what test can measure residual volume?
body plethysmography
what are the normal values for total lung capacity? what indicates restriction? hyperinflation?
80-120%
restricted - less than 80%
hyperinflated - over 120%
what test is used to determine if there is a restrictive process present?
TLC (body plethysmography)
what test is used to differentiate between a parenchymal and extraparenchymal process?
DLCO
