PFT STANDARDS AND INTERPRETATION: RECOMMENDATIONS OF RECENT GUIDELINES

1
PFT STANDARDS AND INTERPRETATIONRECOMMENDATIONS
OF RECENT GUIDELINES

• Prof Dr Sevgi BARTU SARYAL

• Ankara University Medical School Department of
  Pulmonary Diseases

2
STANDARDISATION OF SPIROMETRY WHY?

• Lung function tests are more useful to the
  cliinician when performed with appropriate
  technique with an accurate system.
• Using standard techniques for the performance of
  the tests minimize diagnostic and therapeutic
  errors.
• Standardisation reduces the noice in lung
  function measuremnts and improves the
  identification of the signal of interest.
• Crapo RO
  Respir Care 200348764

3
SOURCES OF NOICE IN SPIROMETRY
Age
Height
Ethnical group
Effect of smoking on FEV1
Gender
Occupation
Socioeconomic factors
Technical
Signal The parameter primarily sought by PFT
Noice Other sources of variation that mask the
signal

• Crapo RO Respir Care 200348764

4
SOURCES OF INTERINDIVIDUAL VARIABILITY
Ethnic origin
Technical
Other ( illness, exposure, socioeconomic)
Height
Age
Gender
Becklake MR. Am J Med 1986801158
5
GUIDELINES FOR STANDARDISATION OF SPIROMETRY

• 1979- ATS. Snowbird Workshop on Standardization
  of spirometry
• 1983- ECSC . Standardized Lung Function Testing
• 1987-ATS. Standardization of Spirometry. Update.
• 1993- ERS (ECSC). Lung Volumes and Forced
  Ventilatory Flows Report of Working Party,
  Standardization of Lung Function Tests
• 1995- ATS. Standardization of Spirometry
• 2005-ATS/ERS Task Force Standardisation of Lung
  Function Testing

6
ATS/ERS Task Force Standardisation of Lung
Function Testing ERJ 2005

• Pellegrino R,
• Viegi G,
• Brusasco V,
• Crapo RO,
• Casaburi R,
• Coates A
• Enright P
• Van der Grinten C
• Gustafsson P

• Jensen R
• Johnson DC
• Pedersen OF
• Wanger J
• Miller MR
• MacIntyre N,
• McKay R
• Navajas D
• Hankinson J

7
ATS/ERS Task Force 2005

• GENERAL CONSIDERATIONS
• Miller MR. General considerations for lung
  function testing. ERJ 200526153
• SPIROMETRY
• Miller MR. Standardisation of spirometry. ERJ
  200526319
• LUNG VOLUMES
• Wanger J. Standardisation of the measurement of
  lung volumes. ERJ 200526511
• DIFFUSING CAPACITY
• MacIntyre N. Standardisation of the single-breath
  determination of carbon monoxide uptake in the
  lung. ERJ 200526720
• INTERPRETATION
• Pellegrino R. Interpretative strategies for lung
  function tests. ERJ 200526948

8
INDICATIONS FOR SPIROMETRY

• DIAGNOSTIC
• To evaluate symptoms, signs or abnormal
  laboratory tests bulgularinin degerlendirilmesi
• To measure the effect of disease on pulmonary
  function
• To screen individuals at risk of having pulmonary
  disease
• To assess prooperative risk
• To assess prognosis
• To assess health status before strenuous exercise
  
• MONITORING
• To assess therapeutic intervention
• To monitor people exposed to injurious agents
• To monitor for adverse reactions to drugs with
  known pulmonary toxicity
• DISABILITY / IMPAIRMENT EVALUATIONS
• To assess patients as part of a rehabilitation
  programme
• To assess risks as part of an insurance
  evaluation
• To assess individuals for legal reasons
• PUBLIC HEALTH
• Epidemiological surveys
• Derivation of reference equations
• Clinical research

9
SPIROMETRY STANDARDISATION
EQUIPMENT PERFORMANCE CRITERIA
ATS 1994 ATS/ERS 2005
EQUIPMENT VALIDATION
QUALITY CONROL
SUBJECT/PATIENT MANOEUVRES
MEASUREMENT PROCEDURES
ACCEPTABILITY
REPEATABILITY
REFERENCE VALUE/INTERPRETATION
CLINICAL ASSESSMENT
FEEDBACK TO TECHNICIAN
QUALITY ASSESSMENT
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PERFORM FVC MANEUVER
Meet acceptibility criteria
ATS 1994 ATS/ERS 2005
NO
YES
NO
Acceptible maneuvers? 3
YES
NO
Meet reprodubility criteria
Best test curve Largest sum FVCFEV1 Determine
other parameters
Determine largest FVC and FEV1
YES
STORE AND INTERPRET
11
SPIROMETRY ACCEPTABILITY CRITERIA

• No artefacts Cough or glottis closure during
  the first second of exhalation, early termination
  or cutoff, variable effort, leak, obstructed
  mouthpiece
• Have good starts Extrapolated volume less than
  5 of FVC or 0.15 L OR time to PEF of less than
  120 ms
• Have a satisfactory exhalation 6 sn of
  exhalation and/or a plateau in the volume-time
  curve OR reasonable duration of a plateau in the
  volume-time curve OR if the subject cannot or
  should continue to exhale

12
UNACCEPTABLE TESTS
Cough
Glottis closure
Variable effort Early termination
Leak
13
SPIROMETRYREPEATABILITY CRITERIA

• ? After 3 acceptable spirograms
• The two largest FVC values must be within 0.15 L
• The two largest FEV1 must be within 0.15 L
• TEST SESSION MAY BE COMPLETED
• ? If these criteria are not met, continue test
  until
• Both criteria are met with new tests OR
• 8 tests are performed OR
• The subject cannot or should not continue
• ?Save the three satisfactory manoeuvres

14
INTERPRETATION
Review and comment on test quality
Comparison of test results with reference values
Comparison with known disease or abnormal
physiological patterns (obstruction, restriction)
Self comparison with former values
Answer the clinical question that prompted the
test
15
REFERENCE EQUATIONS

• Predicted values should be obtained from studies
  of healthy subjects with the same anthropometric
  (sex, age, height) and ethnic characteristics.
• Height and weight should be measured at the time
  of testing
• If possible, all parameters should be taken from
  the same reference source

16
REFERENCE EQUATIONS AND ETHNIC DIFFERENCE

• Race-ethnic reference equations should be used if
  possible. If such equations are not available, a
  race/ethnic adjustment factor based on published
  data may be used for lung volumes.
• Caucasian formulas tend to overpredict values in
  Black subjects by ?12 for TLC, FEV1 and FVC, ?
  7 for FRC and RV.
• An adjustment factor of 0.94 is also recommended
  for Asian-Americans.
• NHANES equations for USA and ECSC equations for
  Europe are recommended.

17
National Health and Nutrition Examination Survey
( NHANES III). For average sized men, the
differences between 3 ethnic groups are not
constant with age. Ethnic differences in lung
function cannot be controlled by applying a
single correction factor to white-based reference
values
Hankinson JL. AM Rev Respir Dis
1999159179
18
LABORATORY NORMALS

• Formerly (ATS 1991) comparison of selected
  reference equations with measurements performed
  by a representative sample of healthy subjects
  (20-40) tested in each laboratory was
  recommended.
• The reference equations that provided the sum of
  residuals ( observed predicted ) closest to
  zero was considered appropriate for that
  laboratory.
• However, in the last consensus it has been stated
  that larger samples (n 100) are needed,
  therefore this is impractical.

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UPPER AND LOWER LIMITS OF NORMAL

• Publications on reference equations should
  include explicit definitions of the upper and
  lower limits of normal range.
• For every functional parameter, values below the
  5th percentile of the frequency distribution of
  values, measured in the reference equation are
  considered to be below the expected normal range.

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REFERENCE EQUATIONS FOR 5th PERCENTILE
MEAN and 5th PERCENTILE in MEN SAPALDIA Study
conducted on 1267 men and 1890 women
Mean and 5th percentile of FEV1 in men of 1.80 m
height as a function of age, data form healthy
never smoking men aged 18-60 years
BRANDLI, O et al. Thorax 200055172
21
REFERENCE EQUATIONS FOR 5th PERCENTILE
MEAN and 5th PERCENTILE in WOMEN SAPALDIA Study
conducted on 1267 men and 1890 women
Mean and 5th percentile of FEV1 in women of
height 1.65 m as a function of age, data from
healthy never smoking women aged 18-60 years.
BRANDLI, O et al. Thorax 200055172
22
TYPES OF VENTILATORY DEFECTS

• Obstructive abnormalities
• Restrictive abnormalities
• Mixed abnormalities

23
OBSTRUCTIVE ABNORMALITIES

• An obstructive ventilatory defect is a
  disproportionate reduction of maximal airflow
  from the lung in relation to maximal volume (VC)
  that can be displaced from the lung.
• Is defined by a reduced FEV1/VC ratio below the
  5th percentile of the predicted value.

24
OBSTRUCTION in EARLY and ADVANCED DISEASE

• EARLY PHASE A slowing in the terminal portion
  of the spirogram due to airflow obstruction of
  small airways occurs. This slowing of expiratory
  flow is reflected in a concave shape of
  flow-volume curve. Proportionally greater
  reduction in FEF75 or FEF25-75 than FEV1 occurs.
• ADVANCED PHASE Central airways are involved
  with reduction in FEV1 out of proportion to the
  reduction in VC.

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OBSTRUCTION and OTHER PARAMETERS

• Measurement of lung volumes is not mandatory to
  identify an obstructive defect.
• An increase in TLC, RV or the RV/TLC ratio above
  the upper limits of natural variability may
  suggest the presence of emphysema, asthma or the
  degree of lung hyperinflation.
• Airflow resistance is more sensitive for
  detecting narrowing of extrathoracic or large
  central intrathoracic airways than peripheral
  intrathoracic airways. It may be useful in
  patients unable to perform a maximal forced
  expiratory manoeuvre.

26
FIXED VALUES vs 5th PERCENTILE

• The definition of obstructive ventilatory defect
  in ATS/ERS task force is consistent with 1991 ATS
  Statement but contrasts with the definitions
  suggested by GOLD and ERS/ATS guidelines on COPD
  in preference of VC rather than FVC and 5th
  percentile rather than fixed FEV1/FVC ratio of
  0.70.
• FVC has been replaced by VC because FVC is more
  dependent on flow and volume. FEV1/VC ratio is
  more capable of accurately identifying more
  obstructive patients.
• In contrast with a fixed value (0.70) 5th
  percentile does not lead to overestimation of
  ventilatory defect in older people with no
  history of exposure to noxious particles or
  gases.

27
LOWER LIMIT OF NORMAL

• A decrease in major spirometric parameters such
  as FEV1, VC, FEV1/VC and TLC below 5th percentile
  is useful in clinical practice.
• When these variables lie near the upper or lower
  limits of normal tests including bronchodilator
  response, DLCO, gas exchange evaluation,
  respiratory muscle strength or exercise testing
  are recommended.

28
GOLD2007 Postbronkodilator FEV1/FVC FEV1 ERS/ATS 2004 FEV1/FVC FEV1 NICE 2004 FEV1
Mild Moderate Severe Very severe lt 70 ? 80 lt 70 50-80 lt 70 30-50 lt 70 lt 30 ? 0.7 ?80 ? 0.7 50-80 ? 0.7 30-50 ? 0.7 lt 30 50-80 30-49 lt 30
29
NHANES III Underidentification (30-50 years of
age) and overidentification (elderly) of airway
obstruction, by decade, in 5,906 never-smokers
and 3,497 current-smokers using the GOLD of
FEV1/FVClt 70 as a criterion
The GOLD guidelines misidentify one half of
abnormal younger adults as normal and 1/5 of
normal adults as abnormal.
Hansen, J. E. et al. Chest 2007131349-355
30
Area under LLNin Normal
False negative False
positive

NHANES III. The ratio of FEV1/FVC in healthy
white women falls below 0.70 at about age 52.
This would occur in men in their early 40 s.
Hankinson JL. AJRCCM 1999159179
31

• According to GOLD criteria, FEV1/FVClt 0.70 and
  FEV1? 80 means Stage I disease.
• In ages 47-49 when LLN for FEV1/FVC is lt 0.70 and
  LLN for FEV1 is gt 80 normal subjects may be
  regarded as having mild COPD.
• Over age 50, LLN for FEV1 lt 80 may be regarded
  as having moderate disease although they are
  normal.

32
Spirometry record of 18.112 adults showed overall
11.7 discordance between pred and 5th
percentile. More discordence was observed in
women and in shorter and older patients.

Aggarwal AN. Respir Care 200651737
33
RESTRICTIVE ABNORMALITIES

• A restrictive ventilatory defect is characterised
  by a reduction in TLC below 5th percentile of the
  predicted value and a normal FEV1/VC.
• Restrictive ventilatory defect should be
  suspected when VC is reduced, FEV1/VC is
  increased(gt85-90) and the flow-volume curve
  shows a convex pattern.

34
COMMENTS ON LUNG VOLUMES

• A reduced VC and a normal or slightly increased
  FEV1/VC is often caused by submaximal inspiratory
  or expiratory efforts and/or patchy peripheral
  airflow obstruction and a reduced VC itself does
  not mean a restrictive defect.
• Pneumothorax and noncommunicating bullae are
  characterised by a normal FEV1/VC and TLCPL but
  low FEV1 and VC values. In these conditions, TLC
  measured by gas dilution techniques will be low.
• A low TLC from a single-breath test (such as VA
  from DLCO test) should not be interpreted as
  restriction since such measurements underestimate
  TLC.

35
Categorisation of Restrictive Pattern
SEVERITY ATS/ERS 2005 ATS 1991
Mild Moderate Moderately severe Severe Very severe FEV1? 70 FEV1 60-69 FEV1 50-59 FEV1 35-49 FEV1 lt 35 VC ? 70 VC lt 70- ? 60 VC lt 60- ? 50 VC lt 50- ? 35 VC lt 35
36
THE UTILITY OF SPIROMETRY IN ASSESSMENT OF
RESTRICTION
The aim of the retrospective study was to
determine the utility of FVC, FEV1 ve FEV 1/FVC
ratio in diagnosing restriction proven by
measurement of lung volumes in 2213 restrictive
cases.

• The negative predictive value for normal FVC was
  high ( 95.7)
• Combined criterion of FVClt LLN ve FEV1/FVC? LLN
  was not so sensitive for excluding restrictive
  defect.

Venkateshiah SB. Lung 200818619
37
MIXED ABNORMALITIES

• A mixed ventilatory defect is characterised by
  the coexistence of obstruction and restriction.
• Is defined as FEV1/VC ratio and TLC below the 5th
  percentiles of the predicted.
• Since VC may be equally reduced in obstruction
  and restriction, the presence of a restrictive
  component in an obstructed patient cannot be
  detected from measurements of FEV1 and VC.
• If FEV1/VC and VC is low, restriction cannot be
  differentiated from hyperinflation. When FEV1/VC
  is low but VC is normal a superimposed
  restriction can be ruled out.

38
Severity scores are closely related with
independent indices of performance such as

• Ability to work
• Function in daily life
• Morbidity
• Prognosis

39
CLASSIFICATION OF SEVERITY

• The severity of pulmonary function abnormalities
  is based on FEV1 pred. This does not apply to
  upper airway obstruction. In addition, it might
  not be suitable for comparing different pulmonary
  diseases.
• At very severe stages of diseases FEV1 may fail
  to identify exact severity.
• FEV1 pred correlates poorly with symptoms and
  may not accurately predict clinical severity or
  prognosis.

40
Severity of any spirometric abnormality based on
FEV1
Degree of Severity FEV1 pred
Mild Moderate Moderately severe Severe Very severe 70 60-69 50-59 35-49 lt35
ATS/ERS 2005 has recommended the severity
classification of both obstruction and
restriction according to FEV1.
41
ADDITIONAL MEASUREMENTS FOR CLASSIFICATION

• The degree of lung hyperinflation (TLC, FRC, RV,
  RV/TLC) parallels the severity of airway
  obstruction.
• Resting lung hyperinflation (IC/TLC) is an
  independent predictor of respiratory and
  all-cause mortality in COPD patients.
  
• 
  Casanova C. AJRCCM 2005171591
• Expiratory flow limitation is also related with
  increased dyspnea and cardiovascular side
  effects. Tidal and forced expiratory flow- volume
  curves can be compared.
• Milic-Emili
  J. AJRCCM 19961541726

42
Can severity of restriction be classified by FEV1?

• The data from 361 patients with restrictive
  pattern were classified according to ATS 1991 and
  ATS/ERS 2005 classification of severity criteria
  and the results were compared.
• 212 (58.7 ) had identical severity
  categorisation.
• Of the 149 discordant results, 91 (60.1) were
  placed in a better category and 58 (39.9 ) in a
  worse category using the new ATS/ERS
  classification.
• The new guidelines tend to underestimate the
  severity of restriction in 25 of patients.
• It has been suggested that TLC should be measured
  when FVC is low and FEV1/FVC ratio is normal .

Aggarwal AN. Respirology 200712759
43
BRONCHODILATOR RESPONSE

• Bronchodilator responsiveness to bronchodilators
  is defined as an integrated physiological
  response involving airway epithelium, nerves,
  mediators and bronchial smooth muscle.
• The response to a bronchodilator can be tested
  either after a single dose or after a clinical
  trial conducted over 2-8 weeks.
• There is no consensus about the drug, dose or
  mode of administering a bronchodilator in the
  laboratory.

44
RECOMMENDED BRONCHODILATOR TEST

• Assess baseline lung function
• Administer salbutamol in four separate doses of
  100?g through spacer
• Reassess lung function after 15 min. If the
  effect of different bronchodilator to be
  assessed, use the same dose and route as used in
  clinical practice.
• An increase in FEV1 and/or FVC ? 12 of control
  and ? 200mL constitutes a positive bronchodilator
  response.
• The lack of a bronchodilator response in the
  laboratory does not preclude a clinical response
  to bronchodilator therapy.

45
INTERPRETATION OF CHANGE IN LUNG FUNCTION

• Evaluation of an individuals change in lung
  function following an intervention or over time
  may be more valuable than a single comparison
  with predicted values.
• For tracking change, FEV1 has the advantage of
  being most repeatable PFT parameter and one that
  measures changes in both obstructive and
  restrictive diseases.
• Other parameters such as VC, IC, TLC and DLCO may
  be tracked in ILD or severe COPD patients.
• When too many indices are tracked simultaneously,
  the risk of false-positive indications of change
  increases.

46
CHANGES IN PFT PARAMETERS
ATS 1991 ATS/ERS 2005
DL,CO
FEF2575
FEV1
FVC
Year to year changes in FEV1 over 1 year should
exceed 15 before being accepted as a clinically
meaningful change.
47
CENTRAL AND UPPER AIRWAY OBSTRUCTION

• Occurs in extrathoracic ( pharynx, larynx,
  extrathoracic portion of the trachea) and
  intrathoracic (intrathoracic trachea and main
  bronchi ) airways.
• Does not lead to reduction in FEV1 and/or VC, but
  PEF can be severely affected.
• Increased FEV1/PEF (mL.L-1.min-1) ratio must
  alert the clinician to the need for an
  inspiratory and expiratory flow-volume loop.
  FEV1/PEFgt 8 suggests central or upper airway
  obstruction.
• Poor initial effort can also affect this ratio.
• At least three maximal and repeatable flow-volume
  curves are necessary.

ERS/ATS 2005
CENTRAL AIRWAY OBSTRUCTION FEF50/FIF50 gt 1,
FEV1/FEV0.5?? 1.5 ERS 2003
48
Variable intrathoracic upper airway obstruction
Variable extrathoracic upper airway obstruction
Fixed upper airway obstruction
EXTRATHORACIC OBSTRCTION VARIABLE
FIXED
INTRATHORACIC OBSTRUCTION
PEF Decreased
Normal or decreased Decreased
FIF50 Normal or decreased
Decreased Decreased
FIF50/FEF50 gt 1
lt 1
? 1
ERS/ATS 2005
49
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