Ch. 16 PFTs (Test 2) Flashcards
Define Tidal Volume
The volume of air (usually in milliliters) that is inhaled or exhaled during a normal breath
The exhaled Vt is usually measured with a _____________ at the bedside or by _________________
respirometer ;
spirometry
Vt is decreased or normal in ________ disease
restrictive
Vt is increased or normal in obstructive disease
know
What is a normal value for Vt
400 to 700 mL ( 3 to 4 mL/lb of IBW or 5 to 6 mL/kg)
Is the maximum volume of air that can be inspired after a normal inspiration
Inspiratory reserve volume (IRV)
IRV normally is not measured during simple spirometry, but if it is, it should be measured from a slow vital capacity
KNOW
Normal value for IRV
3000 mL
IRV can be both
obstructive and restrictive diseases
Expiratory reserve volume (ERV) is the volume of air after a
normal expiration
A normal ERV value is
1000 mL and 20% to 25% of the VC
The volume of air left in the lungs after a maximal expiration
Residual volume (RV)
RV=
FRC-ERV
RV is ___________ in obstructive diseases and ___________ in restrictive diseases
increased;
decreased
A normal RV is
1500 mL
This test is the amount of air left in the lungs after a normal expiration
Functional lung capacity (FRC)
FRC=
ERV+RV
How is FRC measured (3)
- Closed circuit helium dilution
- Open circuit nitogen washout
- Body plethysmography
IC is the maximun amount of air that can be inspired after a normal expiration
know
IC=
Vt+ IRV
A normal value for IC is
3500 mL (75% to 85% of the VC)
The maximum amount of air that can be exhaled after a maximum inspiration
Vital Capacity (VC)
VC=
Vt+IRV+ERV
A normal VC is
4800 mL
A decreased VC may be the result of (6)
- pneumonia
- atelectasis
- pulmonary edema
- pulmonary fibrosis
- kyphoscoliosis
- lung cancer.
Forced vital capacity (FVC) is the maximum amount of air that can beexhaled as
quickly and forcefully as possible after a maximum inspiration
Total lung capacity (TLC) is the amount of air remaining in the lungs at the end of a maximal inspiration
know