Quality Assurance - Flash Cards Flashcards by Brian Blas

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.

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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)

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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.

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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.

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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.

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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.

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If your correction factor keeps changing, what do you suspect is happening?

There is an issue with your equipment.

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What are your 2 primary areas of quality control?

___ ___ 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

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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

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Important:

What is the only difference in the ATS-ERS Standards for the VC and FVC maneuvers?

Time.

VC = 30 seconds
FVC = 15 seconds

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Important:

According to the ATS-ERS Standards, how many liters should your spirometer be able to collect?

8 Liters

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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

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You should associate the Westguard rules and Levey-Jennings Charts with what?

Quality control of ABG data

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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.

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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.

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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.

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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 1. they are free from ___ * bonus: name some of these (5 examples listed) * not necessary to know examples, but helpful 2. the have good ___ extrapolated volume less than ___% of ___ 3. 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 ``` 2. the have good STARTS extrapolated volume less than 5% of FVC 3. 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.