Chapter # 3, Lung Volume Flashcards
Direct Spirometer measures all volumes and capacities except:
- RV
- FRC
- TLC.
- (It’s called Directed Spirometry because it direct measures indivuals exhale gases.
Lung Volume Testing is also called:
Indirect spirometry
There are two types of Indirect Spirometer Testing technique:
- Gas Dillution (Nitrogen washout and He Dilution)
- Body Plethysmography (Body Box)
Indirect Spirometry is performed to measure?
FRC Volume
Which Lung Volume is the most reproducible and provides a consistent baseline for measurements?
FRC
Gas Dilution techniques operates on a principle similar to:
Boyle’s Law (P1 V1 = P2 V2)
All opertates on a principle similar to Boyle’s Law (P1 V1 = P2 V2), which states the volume of gas varies inversely whith its pressure.
Gas Dilution Technique
How much percent of Nitrogen is in the lung?
78%
When people breath normal they breath about 78% of N2 which is normally in the air.
When a patient is performing Open circuit, multiple-Breath Nitrogen WashOut, they should be able to wash out all the Nitrogen from the lungs in about …?
3-4 minutes
Nitrogen Wash Out Test must be carefully initiated from?
FRC baseline levels
Nitrogen Washout Test is succefully complete when:
N2 level decrease to become
<1.5% for at least 3 successive breaths
This is?
Nitrogen Washout leack
It happen when patient breath small amout of air while his treatment allowing N2 inhalation
Nitrogen Washout criteria for acceptability
- The washout tracing should indicate a continually falling concentration of alveolar N2.
- The test should continued until the N2 concentration falls to <1.5% for 3 concecutive breaths.
- Washout should be appropriate for the subject tested (Healthy subjects should washout their N2 in 3-4 minutes)
- The washout time should be reported. (Falure to washout N2 whithin 7 minutes should be noted)
- Multiple measurements should agree within 10%
- At least 15 minutes of room-air breathing should elapse between repeated trials, >1 hours for patients with severe obstructive or bolluos disease
Hilium Dilution is a open or close circuit?
Close
He Dilution Procedure:
- Spirometer is fillid with a known volume of air with added oxygen 25% to 30%
- A volume of He is added approximately 10%.
Criteria for acceptabibily of Helium Dilution Procedure
- Spirometer tracing should show no leacks ( which would cause an overstimation of FRC)
- Test is successfully completed when He reading change by less than 0.02% in 30 seconds or until 10 munutes elapsed.
- Multiple measurement of FRC should agree within 10%
- The Average of acceptable multiple measurements should be reported.
The problem with Gas Dilution Technique is :
Can only measure lung volume in comunication with conducting airways!!!
On patient with Air trapping Gas Dilution Technique will provide not a good measure, Why?
Becauce we can’t measure the gas that the patient can not exhale as a consecuence it will reduce the side of FRC (Understimate)
That’s why Gas Dilution Technique can only measure lung volume in communication with conducting airway
Which Test would you recomend to get the most acurate result on a severe Emphysema patient to measure its FRC? why?
Body Box Technique, because Body Box has the ability to measure lung volume even those with Air Trapping, unlike Gas Dilution Technique that just measure gas volume in communication with Airways
True Or False
In Patients with Air trapping, Plethysmography lung volume are usually larger to those measures with gas dilution technique
True
True or False
Unlike Gas Dilution Technique, Body box include both air in commuication with open airway as well as air trapped within noncommunicating thoracic comparments…
True
BB, criteria for acceptability
- Patient maneuver shows a closed loop without drift.
- Tracing does not go off the screen.
- Panting is 0.5 - 1 Hz.
- Tangents should be within 10%.
- At least 3FRCpleth values shloud agree within 5% and the mean reported.
Is require for the determination of RV, FRC, and TLC
Indirect Spirometry or Lung Volume Testing
Used to measure all volume that can be exhaled
Direct Spirometry
Direct Spirometry can only measures volumes that can be exhaled, unlike Lung Volume testing that measures all
The Volume measured with Body Box is refered as:
Thoracic Gas Volume
(TGV) (VTG)
When Hellium Dilution technique is successfully complete?
when Helium reading change by less than 0.02% in 30 seconds or until 10 minutes has elapsed.
