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Quality Systems in the Pulmonary
Function Laboratory
Carl Mottram, BA RRT RPFT FAARC
Director - Pulmonary Function Labs & Rehabilitation
Associate Professor of Medicine - Mayo Clinic College of
Medicine
Case Presentation
• 31 y.o. female
• History of present illness
• Non-specific cough, tightness in throat and
episodic shortness of breath following URI
• No wheezing noted by patient or on exam
• Exam normal other than obesity (BMI 38)
• LMD orders CXR and spirometry with
diffusing capacity
Case Presentation
• CXR
• Spirometry & DLCO
Pre
External Pulmonary Laboratory
12
Control
Post Albuterol
Predicted
10
Post %Pred
FVC 2.10 2.11 62%
FEV1 0.89 1.36 31%
Flow L/s
8
6
4
2
Ratio 42.4
DLCO
64.5
8.0
30%
0
0
1
2
3
4
5
6
Volume L
Impression: Severe obstruction with a severe reduction
in DLCO. Some improvement with BD
7
8
Case Presentation
• LMD Action Plan
• Orders a CT scan
• Referred to Mayo Clinic for further
evaluation
Case Presentation
• Outside CT negative
• Pulmonary, ENT, and GI consults
scheduled
• Pulmonary physician
• Negative exam
• Lungs clear, patient had coughing spell
during exam, no wheezing or stridor noted
• Questioned outside spirometry results and
orders PFT’s
Case Presentation
Mayo Pulmonary Function Laboratory
• Spirometry & DLCO
12
Control
Post Albuterol
Predicted
10
Pre Post %Pred
2.55 2.48 75%
FEV1
2.27 2.25 79%
Ratio
89
90.7
Flow L/s
FVC
8
6
4
2
0
DLCO
24.2 99%
0
1
2
3
4
5
6
7
8
Volume L
Impression: Borderline restriction most likely 2 to obesity with no
evidence of airflow obstruction or BD response
PFT results affect people!!!
• Further testing
• Labeling (COPD,
Asthma, etc)
• Medicine
• Disability
Guidelines and Standards
• American Thoracic Society
•1987 Revised Spirometry Standards
•1991 Reference Values & Interpretation
•1994 Revised Spirometry Standards
•1995 Diffusing Capacity
• 1999 Guidelines for Methacholine and
Exercise Challenge Testing
•ATS/ERS 2005 Series; General
Laboratory, Spirometry, Diffusing Capacity,
Lung volumes, and Interpretation
Guidelines and Standards
• American Association of Respiratory
Care (AARC)
• Clinical Practice Guidelines (52)
• Spirometry
• Static lung volumes
• Plethysmography
• Diffusing Capacity
• Infant/Toddler Pulmonary Function
Tests
Guidelines and Standards
• American Thoracic Society
• ATS Pulmonary Function Laboratory
Management and Procedure Manual
• Updated 2005
• www.thoracic.org
• Education
• Education Products
CLSI’s Quality System In
Respiratory Care – HS4-A2
Patient
Patient
assessment
Path of workflow
QSE
Clinical
interpretation
application
Evidence of Quality Testing
• Spirometry in Primary Care Practice*
• 30 primary care clinics, 15 trained group
/15 usual group
• 3.4% in usual group and 13.5% in
trained group met ATS acceptability and
reproducibility criteria
• 1,012 pt. tests, 2,928 blows (2.89)
• * Eaton et al, Chest 1999; 116:416-423
Evidence of Quality Testing
• Improving the Quality of Bedside
Spirometry
• Audit of testing outside the PF lab Cleveland Clinic
• 15% - ATS acceptability/reproducibility
criteria
• CI Project - 63.5%
acceptability/reproducibility
•
Stoller JK. Orens DK. Hoisington E. McCarthy K. Bedside spirometry in
a tertiary care hospital: The Cleveland Clinic experience. Respiratory
Care. 47(5):578-82, 2002 May
Evidence of Quality Testing
• Wanger J, Irvin C
Resp
Care 36 (12): 1991
• 13 hospitals, 7
different systems, 5
Bio-QC (3 men, 2 women)
• DLCO CV 11.5 - 18.6
with the largest diff.
24 units
Evidence of Quality Testing
Certification of DLCO Measurements for
Clinical Trials
• Results of the initial DLco simulation tests
from 125 pulmonary laboratories
• 94 (75.2%) Passed with coaching; no hardware
• 24 (19.2%) Failed. Passed after servicing
• 6 (4.8%) Failed. Passed with new equipment
• 1 (0.8%) Site dropped 1
R.L. Jensen, PhD., R.O. Crapo, M.D., P.Y. Berclaz, M.D., Ph, C. Zimmer,
B.S., D.M. ATS abstract 2007
Evidence of Quality Testing
Results from a survey
of PFT labs in Europe and Latin America
Enright, Blonshine, Harris 2007 ERS abstract
Quality Systems in the PFL
Quality Assurance
“Systematic” approach of monitoring
and evaluating quality.
Quality Systems in the PFL
Quality Assurance
• CLSI’s “Path of workflow” Model
• Pre-test
• Testing session
• Post-test
Quality Systems in the PFL
Pre-test
• Pre-test instructions
• Appropriate order
• Questionnaire
• Height* and weight
• Networked systems
• Equipment quality
assurance program
Quality Systems in the PFL
Pre-test
• Subject preparation
• Activities that should preferably be avoided
prior to lung function testing.
• Smoking within 1 hours of testing
• Consuming alcohol within 4 hours of testing
• Performing vigorous exercise within 30
•
minutes of testing
Wearing clothing that substantially restricts
full chest and abdominal expansion
Eating a large meal within 2 hours of testing
•
• Deviations recorded
2005 ATS/ERS Standards
General Laboratory
Quality Systems in the PFL
Pre-test
• Height and weight
•Measured in indoor
clothes without shoes
•Patients with deformities
of the thoracic cage should
have their arm span
measured
•Regression equations
•Ht = arm span/1.06
2005 ATS/ERS Standards
General Laboratory
Quality Systems in the PFL
Pre-test
• Equipment quality
assurance
•Validation/Verification
•Preventive
maintenance
•Documentation and
records (logbooks)
• Mechanical
models
• Biological
models
Quality Systems in the PFL
Pre-test
• Mechanical Model
•3-liter syringe
• 0.5, 1-2, 6 second flows
•Leak checked
•Stored and used in such a
way as to maintain the same
temperature and humidity of
the testing site
•Validated based on
manufacturer
2005 ATS/ERS Standards
recommendations
Standardization of Spirometry
Quality Systems in the PFL
Pre-test
Mechanical Model Plethysmography
• Validation using a known
volume should be performed
periodically
• Model lung with thermal
mass to simulate isothermal
conditions of the lung.
• Accuracy 50 ml or 3%
2005 ATS/ERS Standards
Standardization of Lung Volumes
Quality Systems in the PFL
Pre-test
• Mechanical Model –
Dilution techniques
• Analyzer accuracy and
linearity
• N2 washout: Monthly,
exhalation volumes should
be checked with the
syringe filled with room
air, and inhalation volumes
with the syringe filled with
100% O2.
2005 ATS/ERS Standards
Standardization of Lung Volumes
Quality Systems in the PFL
Pre-test
• Mechanical Models – DLCO
• Syringe DLCO weekly or
whenever problems occur
•VA,VC BTPS ~ 3.2- 3.3L
• DLCO Simulator or BioQC
2005 ATS/ERS Standards
Standardization of DLCO
Quality Systems in the PFL
Pre-test
• Biological Model
• Normal laboratory subjects
• Two individuals (13)
• Establish mean and SD
(minimum 20 samples)
2005 ATS/ERS Standards
General Laboratory
Quality Systems in the PFL
Pre-test
Biological Control - Plethysmography
• At least monthly or whenever errors are suspect 2 reference
subjects (biologic controls) should be tested
2005 ATS/ERS Standards - Standardization of Lung Volumes
Quality Systems in the PFL
Pre-test
Biological Control – N2 washout
• At least monthly or whenever errors are suspect 2 reference
subjects (biologic controls) should be tested
2005 ATS/ERS Standards - Standardization of Lung Volumes
Quality Systems in the PFL
Pre-test
Biologic Control – He dilution
• At least monthly or whenever errors are suspect 2 reference
subjects (biologic controls) should be tested
2005 ATS/ERS Standards - Standardization of Lung Volumes
Quality Systems in the PFL
Pre-test
Biologic Control – Diffusing Capacity
• At least weekly
• Or whenever errors are suspect
• Or whenever a calibration tank is replaced
DLCO and VA from Diffusing Capacity BioQC Technologist #3
25
DLCO Units/Liters
20
15
DLCO
VA
10
5
0
1
5
9
13 17
21
25 29
33 37
41 45
49
53 57
61 65
69 73
77
81 85
89 93
97 101 105 109 113 117
Measurement Number
2005 ATS/ERS Standards - Standardization of DLCO
Quality Systems in the PFL
Biological Quality Control - PF Lab
• Results “Out of range”
 Repeat with another technologist
 Second tech is within limits - record out of range data
 Second tech out of range - trouble-shoot and
document
BioQC1:
FEV1
FVC
TLC (Pleth)
DLCO
ULN
2.95
3.62
6.09
24.5
LLN
2.73
3.35
5.65
21.5
SD
0.05
0.07
0.11
0.75
CV
0.02
0.02
0.02
0.04
Quality Systems in the PFL
Biological Quality Control - DLCO
Bio QC Technologist Comparison
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
1
2
3
4
5
6
7
Model A versus B: Mean difference 0.5
8
9
Quality Systems in the PFL
Subject comparisons: DLCO
35
30
25
20
15
10
5
ie
n
tK
tJ
Pa
t
ie
n
tI
Pa
t
ie
n
tH
Pa
t
ie
n
tG
Pa
t
ie
n
Pa
t
ie
n
tF
tE
Pa
t
ie
n
tD
Pa
t
ie
n
Pa
t
ie
n
tC
tB
Pa
t
ie
n
Pa
t
Pa
t
ie
n
tA
0
Model A versus B - Mean difference 1.5
12
10
8
Abnormal Study: Mild airway obstruction with a significant
response to bronchodilator. Lung volumes suggest hyperinflation.
DLCO is within normal limits.
Flow, L/s 6
4
2
0
0
1
2
3
4
Volume, L
5
6
7
8
Predicted
Control
Post Dilator
Date
4/12/2008
3/12/2008
2/12/2008
1/12/2008
12/12/2007
11/12/2007
10/12/2007
9/12/2007
8/12/2007
7/12/2007
6/12/2007
5/12/2007
4/12/2007
3/12/2007
2/12/2007
1/12/2007
12/12/2006
11/12/2006
10/12/2006
9/12/2006
8/12/2006
7/12/2006
6/12/2006
5/12/2006
4/12/2006
3/12/2006
2/12/2006
1/12/2006
12/12/2005
11/12/2005
10/12/2005
TLC - He Liters
Quality Counts
BioQC Anderson
10
Test performed
9
8
Changed
Sodasorb
7
6
5
BioQC data
-2 SD
+2 SD
4
3
2
1
0
“This is fine as far as it goes.
From here on, it’s who you know.”
Quality Systems in the PFL
Test
• Testing room environment
• Environmental interference
• Technologist’s performance &
training - QSE: Personnel
• Second technologist
• Meeting ATS/ERS acceptability and
repeatability criteria (new guidelines)
Quality Systems in the PFL
Test - QSE: Personnel
• Technologists
• Job qualifications
• Job descriptions
• Orientation
• Training
• Competency assessment
• Continuing education
• Performance appraisal
Quality Systems in the PFL
Test - QSE: Personnel
• Competence Assessment
• Training and on-going
performance evaluations
• NIOSH Spirometry Training
Course
• cdc.gov/NIOSH/topics/spirometry
• AARC’s Spirometry
Training
• National Board for
Respiratory Care
• CPFT and RPFT exams
ATS/ERS Standards
Standardization of Spirometry
Between Maneuver Evaluation
• Minimum of 3 maneuvers
• Acceptable repeatability is achieved when the
difference between the largest and the next
largest FVC is 0.150 L or less AND the
difference between the largest and next largest
FEV1 is 0.150 L or less.
• For those with an FVC of 1.0 L or less both
these values are 0.100 L.
ATS/ERS Standards
Standardization of DLCO
• Should be at least two acceptable tests that
meet the repeatability criteria:
•Within 3 mL/min/mmHg-1 (or 1 mmol/min/kPa)
of each other
•or within 10% of the highest value.
• Report average of at least two acceptable tests
ATS/ERS Standards
Standardization of Lung Volumes
Measurement technique - Plethysmography
• Quiet breathing until a stable end-expiratory
level is achieved
• Close shutter at or near FRC
• Approx 2-3 seconds
• Gentle pants + 10 cmH2O
• 0.5 to 1 Hz (30-60 breaths per minute)
• > 1.5 Hz may lead to errors
• < 0.5 Hz may cause problems with the controlled
leak
ATS/ERS Standards
Standardization of Lung Volumes
Measurement technique –
Plethysmography (cont)
• 3-5 technically satisfactory
panting maneuvers
• Patient then performs an ERV
maneuver followed by a slow
IVC (preferred method)
• “Linked” maneuvers
ATS/ERS Standards
Standardization of Lung Volumes
A.
Shutter closure
B.
A. Preferred method
B. Secondary preferred method
Shutter
Shutter closure
closure
ATS/ERS Standards
Standardization of Lung Volumes
• Alternative method
Shutter closure
•Patient then
performs an IC
followed by a slow
exp. VC
Shutter closure
Pant prior to
shutter closure
Target: < 200 mls
switch-in error
ATS/ERS Standards
Standardization of Lung Volumes
Reporting (Preferred method)
• Repeatability: Obtain > 3 FRCpleth values that
agree within 5%
• Largest FRC – smallest FRC
mean FRC
• Reported FRC is the mean of the technically
satisfactory measurements linked to the technically
satisfactory ERV and IVC maneuvers used for
calculating RV and TLC.
• Reported TLC is the reported value for RV plus the
largest of the technically acceptable IVC’s
ATS/ERS Consensus Statements
Summary
Quality Systems in the PFL
Test Quality Assurance
• Lung volumes - DLCO VA 500 ml
larger than TLC - ???
• Technologist Driven Protocols
• Reference equations
• NHANES III
Quality Systems in the PFL
Test Quality Assurance
Technologist Driven Protocol For Complete
Pulmonary Function Testing with Bronchodilator
• Technologist Driven
Protocols
2: Abnormal Flow,
Volume, or
MD requested TLC
SPIROMETRY
1: Abnormal MVV
FVC, FEV1, FEV%, MVV
TLC
Normal Spirometry
Give Bronchodilator
MVV
< FEV1 x 30
Skip if restrictive pattern with
previous documentation of
no response to Rx
No
No
Normal TLC
Low FEV1 or FVC
Normal FEV1%
Yes
• Flowcharting the
Yes
DLCO
Neuromuscular
Disease
No
Upper Airway
Yes
process
Yes
Airway
Resistance
No
Abnormal
VA
Yes
Resting
OXIMETRY
TLC
No
Technologist Discretion
Maximal Respiratory Pressures
(if neuromuscular diagnosis)
and / or
FIVC Maneuvers
All
tests are
normal with no hx
of pulm. vascular
disease
Resting SpO2
< 88% on room air or oxygen
No
Yes
No
Exercise
OXIMETRY
Yes



SpO2
< 80% or patient
is intolerant to
testing
Yes
PATIENT ASSESSMENT
Did the patient comply with pretest instructions?
Prior to testing a patient with
suspected room air hypoxemia
place pulse oximeter. If resting
SpO2 < 80 on room air perform
spirometry on oxygen (if
prescribed) and cancel lung
volumes and DLCO
Report room air SpO2, do not
exercise
Terminate Testing
Call MD if resting SpO2 <
88% or exercise SpO2 <
85% to recommend ABG's
No
No
>4% Fall in SPO2 &
Normal Resting Saturation &
Normal PF
Yes
Post BD FVC's
PF TESTING COMPLETE
Repeat Oximetry
Quality Systems in the PFL
Post-Test Quality Assurance
• Maneuver selection
• Quality review by second technologist
• “While in-house training may achieve the
desired goals, laboratory directors should
strongly consider the benefits of formal
training programs from outside providers.”
• Feedback to the technicians concerning their
performance should be provided on a
routine basis
2005 ATS/ERS Standards
General Laboratory
Technician Training and Feedback Improve
Test Quality
4.0
Volume grade
3.5
Flow grade
GPA
3.0
Quality control
feedback started
2.5
Site visits and
training update
2.0
1
2
3
4
5
Year
Lung Health Study
Enright: Am Rev Respir Dis 143:1215, 1991
6
7
Quality Systems in the PFL
Post-Test Quality Assurance
• Turn-around time
• Average TRT: <1 day (15%), 1-2 d
(30%), 3-4 d (27%), 5-6 d (15%), >7 d
(3%)
• ATS PFL Registry Abstract AARC 2005,
OF-05-037
• Electronic Medical Record
Quality Systems in the PFL
Does it Work?
• Retrospective review of 18,000 consecutive
pts. at Mayo Clinic
• Ninety percent of the patients were able to
reproduce FEV1 within 120 ml (6.1%), FVC
within 150 ml (5.3%), and PEF within 0.80
L (12%).
American Journal of Respiratory & Critical Care Medicine.
169(2):235-8, 2004 Jan 15.
Evidence of Quality Testing
• Quality Control in Spirometry in the
Elderly*
• 984 controls, 638 COPD pts.
• 95.8% repeatable tests in controls, 87.6%
in COPD
• 4.8 + 1.7 tests per session
• * Bellia et al, AJRCCM 2000; 161:1094-1100
Evidence of Quality Testing
• Quality of Spirometry Test Performance
in Children and Adolescents**
• 4,000 public school students 9-18 yrs.
• 95% of the tests met adult-based ATS
standards
• ** Enright et al, Chest 2000; 118:665-671