Ventilation/Mechanics II Flashcards
Expiratory Reserve Vol (ERV) is?
vol exhaled after normal expiration
~1000ml
Residual Vol (RV) is?
lung vol remaining after max expiration
~1200ml
measure w/ He dilution method
Vital Capacity (VC) is?
difference b/w total lung capacity and residual vol
~4500ml
Vital Capacity eqn
VC = TLC - RV
Functional Residual Capacity (FRC) is?
volume of lungs at rest following normal expiration,
“fxn” of opposing forces of lungs and chest wall
expiratory reserve (useable) and residual volume (not useable) ~2200ml
FRC = ERV + RV
Total Lung Capacity (TLC) eqn?
TLC = VC + RV
~5700ml
Restrictive Lung Disease results in?
↓ compliance:
lung and/or chest wall are less distensible
Ѧ higher intrapleural pressure needed for ∆ in vol
lung vol reduced for given respiratory effort
Lung volumes in Restrictive Lung Disease?
↓ TLC and ↓ RV (ALL lung vols ↓)
Ѧ RV:TLC ratio doesn’t change
Pulmonary Fibrosis is what type of disease?
restrictive lung disease
Obstructive Lung Disease causes?
↑ airway resistance
Asthma results in?
airway constriction and ↑ mucus
Bronchitis results in?
(COPD)
inflamed bronchi, ↑ mucus
Emphysema results in?
(COPD)
alveolar degeneration
Forced Vital Capacity (FVC) is?
max forced expiration at max inspired vol
Forced Expiratory Volume (FEV) is?
forced exp vol at 1 second into expiration
~ 80% of FVC
Lung volumes in Obstructive Lung Disease?
TLC normal
RV ↑ (air trapped in exp) -> ↓ VC
ratio RV:TLC ↑
FEV/FVC% corrects for?
body size
What happens to FEV and FVC in OBSTRUCTIVE disease?
both decrease
What happens to FEV and FEV/FVC% in RESTRICTIVE disease?
↓ diameter has greater effect on FEV than FVC:
FEV decreases
FEV/FVC% stays constant or increases
FEV is fxn of? (3)
1) lung size
2) elasticity of lungs
3) airway diameter (resistance)
Peak Expiratory Flow (PEF) is?
peak flow rate during max effort:
reproducible measure of airflow obstruction,
used to monitor not treat (e.g. asthma)
Hysteresis is?
difference between inflation and deflation of the lung
Compliance is?
∆V/∆P
High compliance means lungs are?
easy to inflate
Filling lung w/ saline does what?
eliminates surface tension = huge compliance
Surface tension is higher in inflation or deflation?
inflation (surfactant is redistributed)
Lung compliance decreased by? (5)
1) higher lung vol
2) pulmonary fibrosis (restrictive dx)
3) pulmonary congestion (blood)
4) surfactant deficiency
5) edema
Lung compliance increased by? (3)
1) low lung vol
2) emphysema (loss of elasticity)
3) age
FRC affected by changes in what?
compliance
Restrictive dx effects FRC how?
decreases compliance ->
decreases FRC
Emphysema effects FRC how?
increases compliance (barrel-chested) -> increases FRC
