Quiz 2 Ch. 3 and 4 Flashcards
When measuring lung volumes, the ultimate goal is to get the
TLC
What does an increased RV/TLC ratio indicate
Hyperinflantion or Air-trapping, severe air-trapping
Which of the following cannot be measured directly
FRC
IC
TLC
RV
RV
Helium dilution uses a ________- circuit
closed
List some things you’ll need to perform helium dilution test
- Closed circuit
- Source of o2
- Helium analyzer
Body box is based on who’s law?
Boyle’s
An increase in the slope of phase 3 indicates…….
Uneven distribution
The N2 concentration is plotted against the exhaled volume and divides into how many phases of exhalation
4
An increased RV and TLC indicates
hyperinflantion
An increased RV w/ a normal TLC indicates
airtrapping
During a nitrogen washout test, what should you expect if you notice a sudden spike or increased in the fall of N2
You have a leak
How long should you wait before restarting a n. washout test ?
15 minutes
What are the three ways to indirectly measure RV
- Helium dilution
- Nitrogen washout
- Body box
What 2 things does the body box measure?
- FRC
- Thoracic gas volume
TLC is the volume of gas…
remaining in the lungs after a maximal inspiration
______________ __________ is the amount of gas remaining in the lungs at the end of a maximal expiration
Residual volume
The ___________ of gas remaining in the lungs at the _____ of a _________ breath describes?
volume;
end;
normal;
Functional Residual Capacity (FRC)
FRC=
ERV+ RV
How do we measure RV?
RV cannot be measured directly
What 2 test can be done with single and multi breaths?
He dilution
N2 washout
What does HE measure? (2)
- FRC
- Estimate lung volumes
The helium is diluted until?
Equilibrium is complete
HE dilution is used to measure……
RV but it may underestimate lung volumes (especially pts w/ poorly ventilated lungs)
Nitrogen washout uses a
open circuit
Pneumatchometer measures the…
flow of gas during breathing
If there is a sudden spike or increase in the fall of N2, then you….
have a leak
If you have a leak
you need to retest
Retest for N2 must wait
at least 15 minutes
For healthy lungs, test can take
3-4 minutes
what are the 2 types of Body box
- constant volume (pressure type)
- flow-based
Which test is the most accurate HE dilution, N2 washout, or Bodybox?
Body box
Changes in alveolar pressure is measured where?
At the mouth when the shutter is closed
Body box will usually give a ________ FRC than dilution or n2 washout
higher
Closed-circuit HE dilution is calculated as part of the…..
and measures
DLCO;
TLC
HE underestimates
lung volumes especially in sick pts
How do you perform a HE dilution?
The pt exhales to the RV, then inhales to the IC and holds that breath for 10 seconds, then is instructed to exhale back to RV
________-circuit N2 washout is plotted against the _________ and divied into 4 phases
open;
volume
How do you perform a N2 washout
Pt exhales to RV and then inhales 100% o2 to reach a maximum inspiration. Pt then slowly exhales again to reserve SVC
How many phases of exhalation are there?
4
Phase 1:
upper airway gas from anatomic dead space consisting of 100% o2
Phase 2:
Mixture of O2 and dead space where the concentrations of O2 and N2 changes abrulty
What 2 phases contain dead space gas and is not used to assess distribution
1 and 2
Phase 3:
Plateau caused by exhalation of alveolar gas, slow and uneven change in O2 and N2— last 30% of VC (even distribution
An increase in the slope in Phase 3 indicates?
An uneven distrubution
Phase 4:
Abrupt increase in N2 until RV is reached (closing volumes)
Closing Volumes at which the expiratory flow becomes severely reduced or stop. Which phase is this?
Phase 4
When airway closure begins, Phase 4….
begins and closing volumes are measured
Closing capacity is determined by measuring closing volumes (2)
- Healthy closing capacity is 30% of TLC
- Increased values = closing early (small airway issue)
In what order should you measure volumes?
1.FRC
2. RV
3. TLC
DLCO measures the diffusion of CO monoxide across
the capillary membrane
What are the normal values for DLCO
greater than or equal to 80%
why do we use CO instead of O2 in DLCO test?
CO adheres to Hemoglobin (HB) approximately 210 times more readily
If there is a significant decrease of CO in exhale sample, what does that indicate?
Good gas exchange (Diffused 80% or more)
If measurements are the same or similar what does that mean?
Gas exchange is limited
(Diffused less than 80%)
What are the 3 types of DLCO
- Single breath (most commonly used)
- Rebreathing (research)
- Intrabreath (excersing)
Causes of low DLCO; anything that hinders your body’s ability to deliver enough o2 to your blood stream, such as:
- COPD exacerbation
- Asthma
- PNA
- Chronic bronchitis
- Pulmonary edema
- Airway obstruction
- OSA
- Pulmonary embolism
- Radiation
CarboxyHB is a stable complex of CO that forms in
RBC when CO is inhaled
COHB greater than 50% are
potentially fatal
Why do you think if your pt is a heavy smoker or smokes just before the test will affect the test?
- increased COHB
- The amount of time to diffuse the increase in CO will take longer than predicated 10 seconds (indicates poor gas exchange) DLCO% is decreased
How does a pt perform DLCO test
Pt breathes normal Vt to establish a baseline, then exhale to RV, then inhales to maximum IRV and holds for 10 seconds
If you have a leak while doing the DLCO your percentage will be
increased
Who’s method measures breath hold for 0.3 of the inspiratory time to the midpoint of the alveolar sample
Jones method
Do not use pt’s actual weight for DLCO. What should we use instead?
IBW
All DLCO volumes must be corrected to STPD
standard temp 0
stand pressure 760 mmHg absolute
dry (no h2o)
The average __ best test are acceptable in DLCO
2
There is a maximum of __ test trys for DLCO
5
An elevated DLCO is usually associated w
circumstances in which there is an increase in HB—-binding sites for CO uptake
If DLCO is low, what disease process is it?
Empheysema
If DLCO is normal what disease(s) is it
CBAB
(W/o E)
If pt has a restrictive disease process, we would look to the DLCO to determine if the restrcition is _____________ or _______________
- interstitial (happening in the lungs)
- extrastriatal ( happening outside of the lungs)
If the DLCO is normal, where is happening at?
it is outside of the lungs
If the DLCO is decreased it is happening
inside of the lungs
What is the normal value for DLCO
greater than or equal to 80%
Every DLCO test uses
CO
If there is a significant decrease of CO in exhale sample, what does that indicate?
Good gas exchange
(Diffused 80% or more)
If measurements are the same or similar that indicates
Gas exchange is limited
(Diffused less than 80%)
DLCO SB is good for everything EXCEPT ….
exercising
Why would DLCO be increased during exercise?
Increased temp, ventilation and blood flow
T or F A decreased FRC, RV, and TLC indicates a restrictive disorder
True
If TLC is decreased what should you expect
Restriction
If TLC is increased what should you expect?
obstruction
An increased RV indicates which of the following?
To much air in the lungs
You have acceptable body plethysmography results if…
- no drift or artifacts (no coughing, leaks)
- Calibration
- Acceptable and replicable
- Frequency 0.5 and 1 hrz
- 3 within acceptable parameters
- FRC within 5%
A healthy closing capacity is roughly what percentage of TLC
30%
Why do we choose CO instead of O2 for DLCO testing?
CO has a 210 greater affinity to bind to hemoglobin than O2
If your pt has an obstructive disease, what would we look to next to determine the severity of gas exchange
DLCO
If DLCO is normal for an obstructive pt what is it usually related to?
CBAB
CF, Bronchietasis, Bronchitis, Asthma
Everything except Emphsyema
If the DLCO is normal in the presence of restriction, what does this mean?
Lung function is normal and the restriction is related to something outside of the lung
If your pt has a restrictive disease, what does the DLCO help determine?
Extrastial or Interstitial
Defining a decreased DLCO in pts w/ mixed defect can be difficult. What do we rely on to help come up with the possible diagnosis?
- Pt history
- work environment
- medical data
Normal HB for Men and women
Men: 13.5 to 17.5
Women: 12.0 to 15.5
What reduces DLCO?
Low HB
The machine uses ______ of HB for males and ____ for females and children
14.6%;
13.4%
Tracer gas is used to estimate
TLC
__________ ___________ is used to calculate alveolar pressure and measures the dco
Driving pressure
When DLCO is decreased or low (80%) what could that indicate?
- poor gas exchange
- It could be restrictive or obstructive
If the pt has an obstruction disease process, we would look at the DLCO to determine the…..
severity of the gas exchange and rule out emphysema
If the DLCO is low (<80%), then the obstruction is….
emphysema related
If the DLCO is normal (80 to 100%), it is usually related to…
CF, Bronchitis, Bronchitasis or Asthma
If you pt has a restrictive disease process we would look to the DLCO to determine if the restriction is ___________ or ____________
interstitial or extrastitial
If DLCO is decreased in the presence of a restriction what does this mean?
its caused interstitially
If the DLCO is normal in the presence of restriction, what does that mean?
The pt has normal lung function and the restriction is related to something outside the lungs
