1. Quality Control Spirometry & Lung Volumes
Gregg L. Ruppel, MEd, RRT, RPFT, FAARC
Adjunct Professor, Pulmonary, Critical Care
& Sleep Medicine
Director, Pulmonary Function Laboratory
St. Louis University Hospital

2. What Quality Control Is
NOT !!

3. What Quality Control Is
“Quality control (QC) is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality criteria or meets the requirements of the client or customer. QC is similar to, but not identical with, quality assurance (QA).”
IT Department
Johns Hopkins University

4. Calibration vs. Quality Control
Calibration adjusts the output of an instrument (spirometer, gas analyzer) to match a known input
Quality control tests an instrument to verify that the output is accurate and/or precise

5. Spirometry Quality Spirometry Spirometer Methods meets ATS/ERS
recommendations
calibration
patient
coaching
software
environmental
factors
open vs.
closed
Q/C
Spirometry
Acceptability
Repeatability
disease state
supervision
training &
competency
cooperation
& effort
age
feedback
language
motivation
Patients
Technologist

6. Accuracy and Precision
2.70
3.00
3.30
Mean 3.00
2.70
2.68
2.73
Mean 2.70
3.00
Accurate, but not very precise
Precise, but not very accurate

7. Spirometry QC* Test How Often What To Do Volume Daily
Calibration check using 3 L syringe
Leak (volume spirometers)
3 cmH2O for 1 minute
(< 30 ml volume loss)
Volume linearity
Quarterly
1 L volumes over entire range of device
Flow linearity
Weekly
3 flow ranges
Timer
Stopwatch
Software
Whenever changed
Log and check biologic control
* ATS/ERS 2005

8. Calibration/Verification Syringes
3 Liter recommended
± 15 ml or 0.5% full scale
3.5% for spirometer calibration checks
Keep syringe at same conditions as spirometer
‘Computerized’ syringes

9. Syringe Calibration Calibrating the Calibrator
Annual calibration of syringe recommended

10. Calibration Check – Volume Spirometers
Daily leak check
Volume within ±3.5% of 3 L (2.895 – 3.105)
Quarterly linearity check across volume range

11. Calibration Check – Volume Spirometers
Is ± 3.5% good enough? *
* McCormack et al. Chest 2007; 131:

12. Calibration Check – Flow Spirometers
Volume within ±3.5% of 3 L (2.895 – 3.105)
3 Flows between 0.5 – 12 L/sec (inject volume between 6 seconds and 0.5 seconds)
Weekly linearity (high, medium, low flows)
Disposable flow sensors – check 1 at least daily

13. Calibration Check – Flow Spirometers

14. Calibration Check – Flow Spirometers

15. Other QC Techniques Syringe flow-volume loops (simulate patient)
Biologic control (normal subject)

16. Body Plethysmograph QC
Flow transducer accuracy same as for spirometry
Box pressure and mouth pressure transducers calibrated (physical) daily
Isothermal lung analog (± 50 ml or 3%)
Biologic controls (2 subjects monthly or when problems are suspected)

17. Physical Calibration Body Box

18. Isothermal Lung Analog
Subject sits in box with jar (holds breath)
Compress hand bulb at Hz
Record VTG tangent
Calculate ‘FRC’ of jar ATPS
Volume of jar = volume of water + connectors – metal wool

19. Biologic Controls for Plethysmography
Lung Volumes – Biologic Control
Liters
VTG
TLCPLETH
2 subjects representative of patient population
Perform VTG according to standard guidelines
FRC and TLC should be within 10% of mean for each control

20. N2 Washout Lung Volume QC
Flow or volume transducer meets standards for spirometry
N2 analyzer zeroed with 100% O2; spanned with air (78.1 ± 0.5%)
Linearity check every 6 months with certified gas or dilution technique (0.5% of expected)
Adjustable large volume syringe (3 L) may be used to simulate patient maneuver
Biologic controls (monthly)

21. N2 Washout QC
3 Liter syringe

22. He Dilution Lung Volume QC
Check for leaks every 24 hours or after circuit changes
Check water level if necessary
Check gas conditioning columns (CO2, water)
Check function of fan or blower
He analyzer stable; drift < 0.02% for 10 minutes
He analyzer linearity using serial dilutions - check quarterly

23. He Dilution QC
Linearity Check

24. Lung Volumes QC Biologic* Control Mean 3.38 3.42 3.57
He N2 Box
Mean
std
cv 4.5% 5.7% 4.3% N
* Looks good on your resume

25. Selecting Biologic Controls
No history of respiratory disease (asthma)
No symptoms
Non-smoker (< 5 pk-yrs and 10 years quit)
Readily available for testing

26. Handling Control Data

27. Biologic Control Data

28. Request “Generic Biocontrols” from
Free Spreadsheet !
Request “Generic Biocontrols” from

29. Biologic Control Data http://www.ezyqc.co.nz
Disclosure: I received a free copy
of the software as a beta tester

30. Biologic Control Data

31. Thanks ! Gregg Ruppel Pulmonary Function Lab
St. Louis University Hospital