Transcript Office spirometry e spirometria domiciliare: i requisiti

Office spirometry e spirometria
domiciliare: i requisiti minimi e loro
rispondenza nelle strumentazioni attuali
Andrea Pelucchi & Antonio Foresi
Servizio di Pneumologia e Fisiopatologia Respiratoria
Sesto San Giovanni
I° Congresso AIPO di Telemedicina Bari 29-30 Ottobre 2004
John Hutchinson, 1811–1861, inventor of the spirometer.
Reprinted with permission from Wellcome Trust Medical
Photographic Library.
Silhouette of John Hutchinson and his spirometer, illustrating correct body
positioning for performance of the vital capacity maneuver
Petty, T. L. Chest 2002;121:219S-223S
Indication for Spirometry
• Diagnosis
• Early detection
• Monitoring
Essential Components of Valid Spirometry
• Equipment Performance
• Testing Technique
• Measurement of Results
• Technician Training
Office spirometry, portable spirometr,
handheld electronic spirometer
home spirometers,office-based
spirometers, standard spirometers
TYPES OF SPIROMETERS
1. Volumetric Spirometers:
•Accumulate and directly measure exhaled air volume as a
function of time;
•Examples are water-sealed, dry rolling seal, and bellows
spirometers;
•Provide direct volume-time tracing;
•In general, are precise, simple to operate, and easy to
maintain;
•May be slightly unwieldy due to size and weight.
TYPES OF SPIROMETERS
2. Flow-Type spirometers:
•Indirectly measure airflow during exhalation; integrate the flows to
obtain expired volume (pneumotachometer, turbine, hot wire
anemometer, vortex, ultrasound beam)
•Large range of flows are measured during a forced expiration: Flow
sensors may perform better at high flow rates (early in maneuver) than
at low flow rates (end of maneuver);
•Often more variable (less precise) than volumetric spirometers;
•Integrity of sensors must be maintained for accurate spirometry
measurements - if sensor is damaged, blocked, or has moisture
condensation or obstruction by mucus, test results may be erroneous;
•Malfunctions in sensors, transducers, and electronics can go
unnoticed - users must be alert for anomalous results;
•Lightweight and portable.
Factors to Consider when Choosing a Spirometer
A spirometer must:
•be simple to use;
•be safe and effective. Ensure compliance with spirometer and
electrical safety standards;
•be capable of simple routine calibration checking and have stable
calibration which allows adjustments by the operator;
•be robust and reliable, with low maintenance requirements;
•provide graphic display of the manoeuvre;
•utilise a sensor which is disposable or can be cleaned and
disinfected;
•be purchased from a reputable supplier who can provide training
and servicing/repair;
•be provided with a comprehensive manual describing its
operation, routine maintenance and calibration;
•use relevant normal predicted values;
•be reasonably priced.
American Thoracic Society.
Standardization of spirometry, 1994 update.
Am J Respir Crit Care Med 1995;152,1107-1136
MINIMAL RECOMMENDATIONS
Petty TL, Weinmann GG.
Building a national strategy for the prevention and management of and research in
chronic obstructive pulmonary disease. National Heart, Lung, and Blood Institute
Workshop Summary. Bethesda, Maryland, August 29-31, 1995.
JAMA 277:246-53;1997.
Early assessment of respiratory function in people at
risk for chronic respiratory diseases…….
Office Spirometers Must Only Report Values for FEV1, FEV6, and the
FEV1/FEV6 Ratio
Technical Requirements for Office Spirometers
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•
•
•
•
Advantages of the newly proposed category of office
spirometers for this purpose include:
lower instrument cost
smaller size
less effort to perform the test
improved ease of calibration checks
an improved quality-assurance program
Office spirometers should not be utilized for diagnostic
testing, surveillance for occupational lung disease,
disability evaluations, or research purposes.
Ferguson GT et al: Chest. 2000;117:1146-1161
Sample volume-time curve illustrating differences between
FVC- and FVC6-derived parameters
Chest. 2003;124:1805-1811.
van Schalkwyk EM, Schultz C, Joubert JR, White NW;
South African Thoracic Society
Standards of Spirometry Committee. Guideline for office spirometry in adults, 2004.
S Afr Med J. 2004 Jul;94(7 Pt 2):576-87.
Ferguson GT, Enright PL, Buist AS, Higgins MW.
Office spirometry for lung health assessment in adults:
A consensus statement from the National Lung Health
Education Program.
Chest. 2000 Apr;117(4):1146-61.
The necessity for each new office spirometry system to have a
"real-world" validation study before it is marketed.
Ferguson GT et al: Chest. 2000;117:1146-1161
Each new office spirometry system must pass a “real
world” validation study, ensuring that both the false positive
and false-negative rates are less than 5 %.
No spirometry system has completed such a validation
study, however, and their “real world” accuracy is
unknown
Enright PL & Ferguson GT et al: Clin Chest Med 21:645-652;2000.
Gold Standard
Precision or Reproducibility
• Is reliability
• Indicates the ability of an instrument to yield
the same measurement for a variable when
the variable is measured repeatedly
• Precision does not infer accuracy
Accuracy or Validity
• The ability of an instrument to measure its
true value.
• If accurate it is also valid and reliable (or
precise)
• Can be accurate at one level (magnitude) of
measurement but inaccurate at others
• Instruments should reflect acceptable
accuracy over range of values you measure
Ten patients were asked to perform the same maneuvers.
They represented various degrees of severity of COPD
Best values with the
Best values with the
REFERENCE
TEST
Subj initials
FV C
FE V 1
PEF
FV C
FE V 1
PEF
db
2,29
0,91
207
2,62
0,84
127,8
de
2,33
1,11
292,8
2,65
1,12
182,4
bl
2,67
1,56
340,8
2,72
1,59
262,8
va
3,99
1,97
441,6
4,62
1,93
279,6
ni
1,5
0,8
148,8
1,75
0,82
111
ru
3,54
2,08
360
3,69
2,09
264,6
lu
4,13
2,71
480,6
4,33
2,68
427,2
ro
4,19
2,45
383,4
4,49
2,29
364,2
gi
3,23
2,32
375,6
3,31
2,28
321
tf
2,58
1,52
328,8
2,74
1,6
258,6
G Liistro et al. – ERS 2004
Coefficient of variability measured in the highly trained subjects
5,0
4,5
4,0
3,5
3,0
FVC
FEV1
PEF
2,5
2,0
1,5
1,0
0,5
OneFlow
Simpli
Miloop
SpiSTAR
SpiPRO
SpiBank
DATO120
Dato70
Vitalo
Easyone
Standard spiro
0,0
G Liistro et al. – ERS 2004
Bland & Altman
Proportional error
Difference (reference-test)
1,2
1
0,8
2
R = 0,2694
0,6
0,4
Bias ? Systematic error?
0,2
0
-0,2
1
2
3
-0,4
Mean
4
5
6
(reference  test )
2
G Liistro et al. – ERS 2004
Bias (l)
FEV1
0,10
0,08
0,06
0,04
0,02
0,00
-0,02
-0,04
-0,06
-0,08
-0,10
EasyOne
OneFlow
Pneumotrac
Microloop
SpiroPro
Spirobank
DatoSpir70
Simplicity
DatoSpir120
SpiroStar
G Liistro et al. – ERS 2004
Difference L
FEV1 SpiroPro
0,4
0,3
UNDERESTIMATION
0,2
0,1
0
-0,1 0
1
2
-0,2
-0,3
-0,4
-0,5
3
4
5
6
R2 = 0.28, p=0.001
Mean L
Difference L/min
PEF Easy One
G Liistro et al. – ERS 2004
80
60
40
20
0
-20 0
-40
-60
-80
-100
-120
100
200
300
400
500
600
700
800
R2 = 0.243, p=0.001
Mean
900
Some devices presented a proportional error for some parameters
FVC
Spirobank
Simplicity
OneFlow
DatoSpir70
SpiroStar
SpiroPro
EasyOne
DatoSpir120
Microloop
Pneumotrac
FEV1
PEF
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
Office-based spirometer value minus portable spirometer
value vs mean of two values
YES
NO
Mortimer, K. M. et al. Chest 2003;123:1899-1907
Change in spirometer performance from 1987 to 2001
1987
2
FVC Deviation (L)
FVC Deviation (L)
2
1
0
-1
-2
-3
2001
1
0
-1
-2
-3
0.5 1.5 2.5 3.5 4.5 5.5 6.5
0.5 1.5 2.5 3.5 4.5 5.5 6.5
Target FVC (L)
Target FVC (L)
Crapo & Jensen Respiratory Care 48:764-772;2003
Effect of errors on respiratory screening
and surveillance programs
Townsend, M. C. et al. Chest 2004;125:1902-1909