quality control spirometry & lung volumes gregg l. ruppel, med, rrt, rpft, faarc adjunct...
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Quality ControlQuality ControlSpirometry & Lung VolumesSpirometry & Lung Volumes
Gregg L. Ruppel, MEd, RRT, RPFT, FAARCGregg L. Ruppel, MEd, RRT, RPFT, FAARC
Adjunct Professor, Pulmonary, Critical CareAdjunct Professor, Pulmonary, Critical Care
& Sleep Medicine& Sleep Medicine
Director, Pulmonary Function LaboratoryDirector, Pulmonary Function Laboratory
St. Louis University HospitalSt. Louis University Hospital
What Quality Control IsWhat Quality Control Is
NOT !!
What Quality Control IsWhat 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 DepartmentJohns Hopkins University
Calibration vs. Quality ControlCalibration vs. Quality Control
Calibration Calibration adjustsadjusts the output of an the output of an instrument (spirometer, gas analyzer) to instrument (spirometer, gas analyzer) to match a known inputmatch a known input
Quality control Quality control teststests an instrument to an instrument to verifyverify that the output is accurate and/or precisethat the output is accurate and/or precise
Spirometry QualitySpirometry Quality
SpirometryAcceptabilityRepeatability
Methods
Patients
Spirometer
Technologist
open vs.closed
patient coaching
meets ATS/ERSrecommendationscalibration
software
environmentalfactors Q/C
age
disease state
language
cooperation& effort
training &competency
supervision
feedbackmotivation
Accuracy and PrecisionAccuracy and Precision
2.703.003.30
Mean 3.00
Accurate, but not very precise
2.702.682.73
Mean 2.70
Precise, but not very accurate
3.00
Spirometry QC*Spirometry QC*Test How Often What To Do
Volume Daily Calibration check using 3 L syringe
Leak (volume spirometers)
Daily 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 Quarterly Stopwatch
Software Whenever changed
Log and check biologic control
* ATS/ERS 2005
Calibration/Verification Calibration/Verification SyringesSyringes
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
Syringe CalibrationSyringe CalibrationCalibrating the CalibratorCalibrating the Calibrator
Annual calibration of syringe recommended
Calibration Check – Calibration Check – Volume SpirometersVolume Spirometers
Daily leak check Volume within ±3.5% of 3 L (2.895 – 3.105) Quarterly linearity check across volume range
Is Is ± ± 3.5% good enough? *3.5% good enough? *Calibration Check – Volume SpirometersCalibration Check – Volume Spirometers
* McCormack et al. Chest 2007; 131:1486-1493
Calibration Check – Calibration Check – Flow SpirometersFlow Spirometers
Volume within ±3.5% of 3 L (2.895 – 3.105)Volume within ±3.5% of 3 L (2.895 – 3.105) 3 Flows between 0.5 – 12 L/sec (inject volume 3 Flows between 0.5 – 12 L/sec (inject volume
between 6 seconds and 0.5 seconds)between 6 seconds and 0.5 seconds) Weekly linearity (high, medium, low flows)Weekly linearity (high, medium, low flows) Disposable flow sensors – check 1 at least dailyDisposable flow sensors – check 1 at least daily
Calibration Check – Calibration Check – Flow SpirometersFlow Spirometers
PFT2 Volume Calibration
-3
-2
-1
0
1
2
3
0 7 14 21 28 35 42 49 56 63 70 77
Days
% E
rro
r
Expiratory Inspiratory
Calibration Check – Calibration Check – Flow SpirometersFlow Spirometers
Other QC TechniquesOther QC Techniques
Syringe flow-volume loops (simulate patient) Biologic control (normal subject)
Body Plethysmograph QCBody 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)
Physical Calibration Body BoxPhysical Calibration Body Box
Isothermal Lung AnalogIsothermal Lung Analog Subject sits in box with jar Subject sits in box with jar
(holds breath)(holds breath) Compress hand bulb at Compress hand bulb at
0.5-1.0 Hz Hz Record VRecord VTGTG tangent tangent Calculate ‘FRC’ of jar Calculate ‘FRC’ of jar
ATPSATPS Volume of jar = volume of Volume of jar = volume of
water + connectors – water + connectors – metal woolmetal wool
Biologic Controls for Biologic Controls for PlethysmographyPlethysmography
2 subjects 2 subjects representative of representative of patient populationpatient population
Perform VPerform VTGTG according
to standard to standard guidelinesguidelines FRC and TLC should FRC and TLC should
be within 10% of mean be within 10% of mean for each controlfor each control
Lung Volumes – Biologic Control
Liters
VTG TLCPLETH
NN22 Washout Lung Volume QC 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)
NN22 Washout QC Washout QC
3 Liter syringe
He Dilution Lung Volume QCHe 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
He Dilution QCHe Dilution QC
Linearity Check
Lung Volumes QCLung Volumes QC
Mean 3.38 3.42 3.57
std 0.15 0.20 0.15
cv 4.5% 5.7% 4.3%
N 11 11 12
He N2 BoxBiologic* Control
* Looks good on your resume
Selecting Biologic ControlsSelecting Biologic Controls
No history of respiratory No history of respiratory disease (asthma)disease (asthma)
No symptomsNo symptoms Non-smoker (< 5 pk-yrs Non-smoker (< 5 pk-yrs
and 10 years quit)and 10 years quit) Readily available for Readily available for
testingtesting
Handling Control DataHandling Control Data
Biologic Control DataBiologic Control DataPFT Quality Control (HAW)Medical Graphics BreezePF
3.82
2.81
2.11
2.98
2.88
5.49
3.84
2.81
2.09
2.96
2.85
5.48
3.83
2.86
2.22
3.17
2.76
5.45
3.82
2.87
2.24
0.00
1.00
2.00
3.00
4.00
5.00
6.00
FVC FEV1 FEF25-75 N2-FRC Pl-FRC Pl-TLC
Mean Volumes by Test
Vol
ume
(lite
rs)
Room 1 PFT2 TenetCare PFT3 TenetCare PFT6 MGC
Free Spreadsheet !Free Spreadsheet !
Request “Generic Biocontrols” fromRequest “Generic Biocontrols” from
[email protected]@aarc.com
Biologic Control DataBiologic Control Data
http://www.ezyqc.co.nz
Disclosure: I received a free copyof the software as a beta tester
Biologic Control DataBiologic Control Data
Thanks !Thanks !
Gregg RuppelGregg Ruppel
Pulmonary Function LabPulmonary Function Lab
St. Louis University HospitalSt. Louis University Hospital
[email protected]@slu.edu