Quality Assurance - Flash Cards
If a 3L spirometer consistently measures 2.5L on 3 quality control measurements, is is precise or accurate?
Precise. All of the measurements are the same. They are not within the margin or error for accuracy, which is 2900 ml to 3100 ml (3.5%) for a 3L spirometer.
if a 3L spirometer measures 2.9L, 3.0.L, and 3.1L on 3 attempts, is it accurate or precise?
Accurate. The mean measurement is 3.0L, which is within the margin of error for a 3L syringe (3.5% or 2900-3100 ml)
At least how many points do you need to measure linearity?
You need at least 3 points along the physiologic range of measurement. A range that is clinically significant.
How would you confirm linearity of a device during a quality control analysis?
Take measurements of the high and low values within a clinically significant range, and a 3rd measurement between the high and low. A total of 3 or more measurements are needed to determine linearity.
What is the difference between repeatability and reproducibility?
Repeatability will produce the same results over a short period of time. the method and location has not changed.
Reproducibility will produce the same results on different machinery, at a different time or place, etc.
The exam states that a biological control will be used to test PFT equipment. What is a biological control?
A person (typically employed with the lab) that has normal lung function and performs test for quality control purposes.
If your correction factor keeps changing, what do you suspect is happening?
There is an issue with your equipment.
What are your 2 primary areas of quality control?
___ ___ standards
___ ___ standards
Equipment performance standards
type of equipment
type of maintenance
type of test signals for checking accuracy and precision
Patient performance standards
technologist ability to operate equipment
instruction and coaching of the patient
patient effort and cooperation
insuring collected data meets acceptable standards
Very Important:
ATS-ERS Standards for Equipment Performance
Vital Capacity:
what is the acceptable range of measurement in liters?
what is the acceptable margin of error in percent (for measurement accuracy)?
what is the flow range?
what is the time of the test in seconds?
Forced Vital Capacity:
what is the acceptable range of measurement in liters?
what is the acceptable margin of error in percent (for measurement accuracy)?
what is the flow range?
what is the time of the test in seconds?
Vital Capacity:
what is the acceptable range of measurement in liters? 0.5-8L
what is the acceptable margin of error in percent? +/- 3%
what is the flow range? up to 14L
what is the time of the test in seconds? 30 seconds
Forced Vital Capacity:
what is the acceptable range of measurement in liters? 0.5-8L
what is the acceptable margin of error in percent? +/- 3%
what is the flow range? up to 14L
what is the time of the test in seconds? 15 seconds
Important:
What is the only difference in the ATS-ERS Standards for the VC and FVC maneuvers?
Time.
VC = 30 seconds FVC = 15 seconds
Important:
According to the ATS-ERS Standards, how many liters should your spirometer be able to collect?
8 Liters
Important:
According to the ATS-ERS Standards, what is the acceptable flow range for the PEF, FEF 25-75, MVV?
What is the acceptable margin of error in percent for the above mentioned flow based maneuvers?
Up to 14 Liters of flow is considered acceptable
+/- 5% margin of error is considered acceptable
You should associate the Westguard rules and Levey-Jennings Charts with what?
Quality control of ABG data
How many standard deviations from the mean are within an acceptable limit for ABG values?
ABG’s are acceptable within 2 standard deviations of the mean.
Explain the difference between a random error and an out of control electrode.
A random error will be indicated by a single result that is outside of the margin of error (typically 2 standard deviations from the mean) on an ABG.
An out of control electrode will be indicated by 2 or more erroneous results reported from the same electrode.
in control random error trend shift out of control
which of the following electrode descriptions should require action from the technologist? what should be done?
No action should be taken for any of the descriptions other than “out of control”.
If an electrode is out of control, it should be checked and/or replaced.
True or False:
Before performing quality control tests, all gas analyzers (O2, N2, CO2, CO, He, etc.) must be calibrated.
True.
Note: proper calibration should consider 2 parameters:
physiologic range to be measured
sampling conditions of the actual test.
What are the FiO2 and FeO2 calibrations values for O2 analyzers?
FiO2: 21% - 100%
FeO2: 12% - 21%
What would you use to calibrate the following transducers on a body plethysmograph?
Mouth pressure transducer?
Box pressure transducer?
Flow transducer?
Mouth pressure transducer - water/mercury barometer
Box pressure transducer - sine wave rotary pump
Flow transducer - rotameter
You are performing quality control of a body plethysmograph using an isothermal lung model. How would you determing the volume of the isothermal lung model?
Fill the isothermal lung model with water, and then measure the volume of water it took to fill it.
You are performing quality control of a body plethysmograph using an isothermal lung model that contains a copper sponge. What is the purpose of the sponge?
The copper sponge in an isothermal lung model is used as a heat sink in order to keep the temperature constant. Remember, “Iso-Thermal” aka one-temperature.
You are performing quality control of a body plethysmograph using an isothermal lung model, which contains a copper sponge. What is the purpose of the sponge?
It is used as a heat sink in order to keep the temperature constant. “Iso-thermal” = “one-temperature.”
“unknown control specimens are sent out to different laboratories using the same make and model of analyzers”
This statement describes:
multiple machine analysis?
gas exchange validation device?
proficiency testing?
Proficiency testing
This device allows precise mixtures to be equilibrated with whole blood or a buffer solution. After an equilibration period, the sample is transferred to the blood gas analyzer.
AKA…
This device allows the technologist to input a desired PaO2 into a blood sample or buffer solution, in order to test it on an O2 analyzer to verify the analyzer reads the correct value.
Tonometer/tonometry
This is the “method of choice” for precise control of the PO2 electrode
VERY IMPORTANT - lots of exam questions
ATS-ERS Standards for Patient Performance
Acceptability Criteria - individual spirograms are acceptable if
- they are free from ___
* bonus: name some of these (5 examples listed)
* not necessary to know examples, but helpful - the have good ___
extrapolated volume less than ___% of ___ - they have satisfactory ___
___ seconds of ___ and/or a plateau in the volume/time curve.
Acceptability Criteria - individual spirograms are acceptable if
1. they are free from ARTIFACTS cough/glottic closure during the first second of exhalation early termination or cutoff variable effort leak obstructed mouthpiece
- the have good STARTS
extrapolated volume less than 5% of FVC - they have satisfactory EXHALATION
6 seconds of EXHALATION and/or a plateau in the volume/time curve.
VERY IMPORTANT - lots of exam questions
ATS-ERS Standards for Patient Performance
Acceptability Criteria - individual spirograms are acceptable if
- they are free from ___
* bonus: name some of these (5 examples listed)
* not necessary to know examples, but helpful - the have good ___
extrapolated volume less than ___% of ___ - they have satisfactory ___
___ seconds of ___ and/or a plateau in the volume/time curve.
Acceptability Criteria - individual spirograms are acceptable if
1. they are free from ARTIFACTS cough/glottic closure during the first second of exhalation early termination or cutoff variable effort leak obstructed mouthpiece
- the have good STARTS
extrapolated volume less than 5% of FVC - they have satisfactory EXHALATION
6 seconds of EXHALATION and/or a plateau in the volume/time curve.
VERY IMPORTANT - lots of exam questions
ATS-ERS Standards for Patient Performance
Repeatability Criteria
How many acceptable spirograms should you obtain?
Should you keep testing until you have the acceptable amount?
What is the maximum number of tests a patient can perform?
How many ml should the 2 largest FVC’s be within of each other?
How many ml should the 2 largest FEV1’s be within of each other?
You should always save the __#__ best maneuvers.
How many acceptable spirograms should you obtain? 3
Should you keep testing until you have the acceptable amount? Yes. Do not stop testing until you have 3 good efforts, you have done max amount of tests, or the pt cannot continue.
What is the maximum number of tests a patient can perform? 8 max.
How many ml should the 2 largest FVC’s be within of each other on the 2 best tests? 150 ml
How many ml should the 2 largest FEV1’s be within of each other on the 2 best tests? 150 ml
You should always save the __3__ best maneuvers.
IMPORTANT
You are performing an FVC test:
A minimum of ___ acceptable tests should be obtained
Tracing should show a minimum of ___seconds of forced effort
The two best tests are the highest sum of ___ and ___ and should be within ___% or ___ml of each other.
A minimum of 3 acceptable tests should be obtained.
You need a minimum of 6 seconds of forced effort on the FVC.
The 2 best tests would be the highest sum of FVC and FEV1, and should be within 5% or 150ml of each other
IMPORTANT: ATS-ERS Standards
What should you report on an FVC test?
You report the “best test” of the 3 acceptable efforts, which is the one with the highest combined FVC and FEV1.
You report the best FVC (no matter which of the 3 tests it came from)
You report the best FEV1 (no matter which of the 3 tests it came from)
True or False:
The end-expiratory level of the 3 breaths immediately before the SVC maneuver must not vary by more than 100ml.
True. if there is a large variation, you can suspect the patient is not breathing consistently or there is a leak.
You are performing and SVC test. You need at least ___ acceptable maneuvers within ___% or 150 ml of each other.
For the SVC you need at least 2 acceptable results within 5% or 150 ml of each other.
IMPORTANT: ATS-ERS Standards
What should you report on an SVC test?
You report the largest SVC measured.
IMPORTANT: ATS-ERS Standards
At least how many seconds is an acceptable MVV?
Measured MVV should exceed FEV1 x ___
How many acceptable efforts do you need?
What do you report?
An acceptable MVV is at least 12 seconds
Measured MVV should exceed FEV1 x 35
You need at least 2 acceptable MVV efforts
You report the best MVV
Exam “trick” question:
The exam states you have a patient with a predicted MVV of 120. The pt’s MVV is 50. How do you verify this information?
You check FEV1 x 35. If the patient’s measured MVV is better than that or close, it is accurate.
Be careful with predicted values. A patient may have a high predicted value but have obstructive disease. Always check FEV1 x 35 to verify MVV.
Helium dilution:
What should you do if the patient goes tachypneic?
How do you maintain baseline during the test?
When is the test over?
Your patient fails to reach equlibrium. What do you suspect?
What do you report for a helium dilution test?
What should you do if the patient goes tachypneic? Check the CO2 scrubber.
How do you maintain baseline during the test? By adding oxygen as it is consumed from the system.
When is the test over?The test is over when the helium concentration does not change by more that 0.02% over 30 seconds, or 7 minutes passes.
Your patient fails to reach equlibrium. What do you suspect? A leak. Failure to reach equilibrium indicates a leak in the system.
What do you report for a helium dilution test? You report the mean value of the three largest acceptable FRC’s.
What do you report for a nitrogen washout test?
You report the mean average of 2 acceptable attempts within 10% of each other.
What do you report for a body plethysmography test?
You report the average of 3 or more acceptable attempts.
IMPORTANT: DLCO-SB
The inspired volume should be more than ___% of ___.
The DLCO-SB should be more than 85% of SVC.
DLCO-SB
Breath hold should be stable for ___ seconds
10 seconds
What do you report on a DLCO-SB?
You report the mean of at least 2 acceptable maneuvers.
Note: DLCO values that are adjusted for Hb should be reported.
True or False: DLCO-SB
The washout volume should be 0.75-1.0L. If the patient’s VC is less than 2 liters, the washout volume can be reduced to 0.5L and included on the report
True
Prior to a DLCO-SB, the patient should avoid smoking for how many hours?
24 hours. Otherwise their COHb will alter the results.
