Fouty: Pulmonary Function Tests Flashcards
85% of patients who complain of dyspnea on exertion usually due to what 2 things
lung or heart disease
3 main diseases of the lungs
airways
interstitial
pulmonary vascular
the total work of breathing is a combination of what 2 things
restrictive work
elastic work
work that moves air in and out of lungs
resistance work
work that distends lungs and chest wall
elastic work
respiratory rate in a minute
frequency
tidal volume per breath
Vt
lung volume that is high has very little what
resistance
minimal work has a tidal volume of 400 and how many breaths per minute
12-18
purpose of PFTs (pulmonary function tests)
if pulmonary disease is present
type of disease
severity of disease
lung volumes
airflow
adequacy of pulmonary vasculature
respiratory muscle strength
variables measured by PFTs
normal breathing=
tidal volume
big breath in measurement
total lung capacity
blow all of the breath out
vital capacity
end up with some air in the lungs after expiration
residual volume
4 volumes that makes up total lung capacity
tidal volume
expiratory reserve volume
inspiratory reserve volume
residual volume
4 capacities
functional residual capacity
inspiratory capacity
vital capacity
total lung capacity
how to measure residual volume
FRC-ERV
how to measure TLC
VC + residual volume
breathing in and out normally, what point do you come back to
functional residual capacity (resting expiration)
what is activated if you want to go lower than functional residual capacity
muscles of expiration
what is activated if you want to go higher than functional residual capacity
muscles of inspiration
How Do You Determine Total Lung Capacity if You Can’t Measure Residual Volume?
functional residual capacity - expiratory reserve volume (then add that to vital capacity to get TLC)
a way to measure functional residual volume that has limitations of profusion of gas not being uniform
helium dilution
another way of measuring functional residual volume that uses boyle’s law
“body box”
lung volumes can be what 3 things
increased, decreased, normal
most important test to check lung volumes
total lung capacity (by body box)
2nd thing to look at to check lung volumes
functional residual volume
TLC or FRC > Upper limits of normal (ULN)
greater than 120% predicted per GOLD
lung volumes increased
TLC or FRC < Lower limits of normal (LLN)
Less than 80% predicted per GOLD
lung volumes decreased
a ______ TLC defines restrictive physiology
decreased
a way to measure airflow through the lungs
spirometry
Most people blow out ____% of what you are trying to at 1 second
80%
normal spirometry
normal spirometry
airflow obstruction
main thing to look at when checking airflow through the lungs
FEV1/FVC ratio
increased airflow
what to use to determine airflow obstruction
spirometry
If the _______ is less than the lower limits of normal (LLN), the patient has airflow obstruction
FEV1/FVC
normal flow-volume loop
_____ decreases as lung volume gets smaller
flow rate
no matter how hard you breathe out at this point, there is no increase in flow
effort-independent flow
pressure in pleural space is normally ______ keeping airways open
negative
expiratory flow loop has effort-dependent + _______ flow
effort-independent
in many cases of airway obstruction, ______ stays the same
total lung capacity
in emphysema, ______ frequently changes
TLC
what to use when identifying upper airway obstruction
flow-volume loops
inspiratory loop abnormal
variable extrathoracic obstruction
expiration on L
inspiration on R
expiratory loop abnormal
variable intrathoracic obstruction
fixed obstruction
kid w/ epiglottitis
variable extrathoracic obstruction
key things to look at for airflow
FEV1/FVC ratio
flow-volume loop (upper airway obstruction)
4 types of lung physiology
normal
obstructive
restrictive
mixed
how to determine effectiveness of area of gas exchange
DLCO (diffusing capacity of the lung for CO)
diffusing capacity of the lung for CO determined by what 3 things
surface area
diffusion gradient
presence of Hb
____ is perfusion limited (pressure equilibrates immediately and no diffusion)
nitrous oxide
diffusion limited; breathe in and hold for 10 seconds and any blood passing through will be exposed to ____
CO
____ binds hemoglobin more adequately than O2
CO
CO in plasma never completely equilibrates with the CO in alveolar space, so there is always a _____ for CO
diffusion gradient
R: emphysema
decreased surface area in emphysema decreases _____
DLCO
dyspnea on exertion
emphysema
interstitial lung disease can decrease ____ by thickening of membrane
DLCO
L: normal
R: interstitial lung disease
pulmonary fibrosis
alveolar filling decreases _____
DLCO
pulmonary embolism
decreased pulmonary blood flow decreases _____
DLCO (less blood flow downstream less Hb available to bind to CO)
pulmonary arterial HTN decreases pulmonary blood flow and therefore decreases what
DLCO
pulmonary arterial HTN
Marker of adequacy of gas-exchange
Determined by:
surface area
diffusion gradient
presence of hemoglobin
Normalize to alveolar volume
DLCO/VA
DLCO (diffusing capacity of CO)
inspiratory maximum effort (for respiratory muscle strength)
PImax
expiratory maximum effort (for respiratory muscle strength)
PEmax
Exhale to Residual Volume put your hand tightly over your mouth, plug your nose, and inhale as hard as you can
Mueller maneuver (PImax)
Inhale to TLC, put your hand tightly over your mouth, plug your nose, and exhale as hard as you can
Valsalva maneuver (PEmax)
TLC/FRC and FEV1/FVC in normal range
normal physiology
FEV1/FVC less than LLN
obstructive physiology
TLC/FRC less than LLN
restrictive physiology
TLC/FRC and FEV1/FVC less than LLN
mixed obstructive-restrictive disease
