PFT STANDARDS AND PFT STANDARDS AND INTERPRETATION:INTERPRETATION:

RECOMMENDATIONS OF RECOMMENDATIONS OF RECENT GUIDELINESRECENT GUIDELINES

Ankara University Medical Ankara University Medical School Department of School Department of Pulmonary DiseasesPulmonary Diseases

Prof Dr Sevgi BARTU SARYALProf Dr Sevgi BARTU SARYAL

STANDARDISATION OF STANDARDISATION OF SPIROMETRY: WHY?SPIROMETRY: WHY?

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

Crapo RO Respir Care 2003;48:764Crapo RO Respir Care 2003;48:764

Effect of smoking on FEV1

Age

Ethnical group

Socioeconomic factors

Occupation

Technical

Gender

Height

SOURCES OF NOICE IN SPIROMETRY

Signal: The parameter primarily sought by PFT Noice: Other sources of variation that mask the signal

Crapo RO Respir Care 2003;48:764Crapo RO Respir Care 2003;48:764

SOURCES OF INTERINDIVIDUAL VARIABILITY

TechnicalEthnic originOther ( illness,

exposure, socioeconomic) Height

GenderAge

Becklake MR. Am J Med 1986;80:1158

GUIDELINES FOR GUIDELINES FOR STANDARDISATION OF STANDARDISATION OF

SPIROMETRYSPIROMETRY

1979- ATS1979- ATS. Snowbird Workshop on . Snowbird Workshop on Standardization of spirometryStandardization of spirometry1983- ECSC1983- ECSC . Standardized Lung Function . Standardized Lung Function TestingTesting1987-ATS.1987-ATS. Standardization of Spirometry. Standardization of Spirometry. Update. Update. 1993- ERS (ECSC).1993- ERS (ECSC). Lung Volumes and Forced Lung Volumes and Forced Ventilatory Flows: Report of Working Party, Ventilatory Flows: Report of Working Party, Standardization of Lung Function TestsStandardization of Lung Function Tests1995- ATS1995- ATS. Standardization of Spirometry. Standardization of Spirometry2005-ATS/ERS Task Force:2005-ATS/ERS Task Force: Standardisation of Standardisation of Lung Function TestingLung Function Testing

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

Pellegrino R,Pellegrino R,

Viegi G,Viegi G,

Brusasco V, Brusasco V,

Crapo RO, Crapo RO,

Casaburi R, Casaburi R,

Coates ACoates A

Enright PEnright P

Van der Grinten CVan der Grinten C

Gustafsson PGustafsson P

Jensen RJensen RJohnson DCJohnson DCPedersen OFPedersen OFWanger JWanger JMiller MRMiller MRMacIntyre N, MacIntyre N, McKay RMcKay RNavajas DNavajas DHankinson JHankinson J

GENERAL CONSIDERATIONSGENERAL CONSIDERATIONSMiller MR. General considerations for lung function testing. Miller MR. General considerations for lung function testing.

ERJ 2005;26:153ERJ 2005;26:153 SPIROMETRYSPIROMETRYMiller MR. Standardisation of spirometry. ERJ 2005;26:319Miller MR. Standardisation of spirometry. ERJ 2005;26:319 LUNG VOLUMESLUNG VOLUMESWanger J. Standardisation of the measurement of lung Wanger J. Standardisation of the measurement of lung

volumes. ERJ 2005;26:511volumes. ERJ 2005;26:511 DIFFUSING CAPACITYDIFFUSING CAPACITY MacIntyre N. Standardisation of the single-breath MacIntyre N. Standardisation of the single-breath

determination of carbon monoxide uptake in the lung. ERJ determination of carbon monoxide uptake in the lung. ERJ 2005;26:7202005;26:720

INTERPRETATIONINTERPRETATIONPellegrino R. Interpretative strategies for lung function tests. Pellegrino R. Interpretative strategies for lung function tests.

ERJ 2005;26:948ERJ 2005;26:948

ATS/ERS Task Force 2005

INDICATIONS FOR SPIROMETRYINDICATIONS FOR SPIROMETRYDIAGNOSTICDIAGNOSTIC To evaluate symptoms, signs or abnormal laboratory tests bulgularının To evaluate symptoms, signs or abnormal laboratory tests bulgularının

değerlendirilmesideğerlendirilmesi To measure the effect of disease on pulmonary function To measure the effect of disease on pulmonary function To screen individuals at risk of having pulmonary disease To screen individuals at risk of having pulmonary disease To assess prooperative risk To assess prooperative risk To assess prognosis To assess prognosis To assess health status before strenuous exercise To assess health status before strenuous exercise MONITORINGMONITORING To assess therapeutic interventionTo assess therapeutic intervention To monitor people exposed to injurious agents To monitor people exposed to injurious agents To monitor for adverse reactions to drugs with known pulmonary toxicity To monitor for adverse reactions to drugs with known pulmonary toxicity DISABILITY / IMPAIRMENT EVALUATIONSDISABILITY / IMPAIRMENT EVALUATIONS To assess patients as part of a rehabilitation programme To assess patients as part of a rehabilitation programme To assess risks as part of an insurance evaluation To assess risks as part of an insurance evaluation To assess individuals for legal reasons To assess individuals for legal reasons PUBLIC HEALTHPUBLIC HEALTH Epidemiological surveys Epidemiological surveys Derivation of reference equations Derivation of reference equations Clinical research Clinical research

SPIROMETRY STANDARDISATIONSPIROMETRY STANDARDISATIONEQUIPMENT PERFORMANCE CRITERIA

EQUIPMENT VALIDATION

QUALITY CONROL

SUBJECT/PATIENT MANOEUVRES

MEASUREMENT PROCEDURES

ACCEPTABILITY

REPEATABILITY

REFERENCE VALUE/INTERPRETATION

CLINICAL ASSESSMENT

QUALITY ASSESSMENTFEEDBACK TO TECHNICIAN

ATS 1994ATS/ERS 2005

PERFORM FVC MANEUVER

Meet acceptibility criteria

Acceptible maneuvers 3

Meet reprodubilitycriteria

Best test curve:Largest sum FVC+FEV1

Determine other parameters

STORE AND INTERPRET

Determine largest

FVC and FEV1

YES

YES

YES

NO

NO

NO

ATS 1994ATS/ERS 2005

SPIROMETRY SPIROMETRY ACCEPTABILITY CRITERIAACCEPTABILITY CRITERIA

No artefacts : No artefacts : Cough or glottis closure during the Cough or glottis closure during the first second of exhalation, early termination or first second of exhalation, early termination or cutoff, variable effort, leak, obstructed mouthpiececutoff, variable effort, leak, obstructed mouthpiece

Have good starts:Have good starts: Extrapolated volume less than Extrapolated volume less than 5% of FVC or 0.15 L OR; time to PEF of less than 5% of FVC or 0.15 L OR; time to PEF of less than 120 ms 120 ms

Have a satisfactory exhalation: Have a satisfactory exhalation: 6 sn of exhalation 6 sn of exhalation and/or a plateau in the volume-time curve OR; and/or a plateau in the volume-time curve OR; reasonable duration of a plateau in the volume-reasonable duration of a plateau in the volume-time curve OR; if the subject cannot or should time curve OR; if the subject cannot or should continue to exhalecontinue to exhale

UNACCEPTABLE TESTS

Cough

LeakVariable effortEarly termination

Glottis closure

SPIROMETRYSPIROMETRYREPEATABILITY CRITERIAREPEATABILITY CRITERIA

After 3 acceptable spirograms: After 3 acceptable spirograms: The two largest FVC values must be within 0.15 LThe two largest FVC values must be within 0.15 L

The two largest FEVThe two largest FEV11 must be within 0.15 L must be within 0.15 L

TEST SESSION MAY BE COMPLETED TEST SESSION MAY BE COMPLETED If these criteria are not met, If these criteria are not met, continue continue test until test until

Both criteria are met with new tests Both criteria are met with new tests OROR;;8 tests are performed 8 tests are performed OROR;;The subject cannot or should not continue The subject cannot or should not continue

Save the three satisfactory manoeuvresSave the three satisfactory manoeuvres

INTERPRETATIONINTERPRETATION

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

REFERENCE EQUATIONSREFERENCE EQUATIONS

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

REFERENCE EQUATIONS AND REFERENCE EQUATIONS AND ETHNIC DIFFERENCEETHNIC DIFFERENCE

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

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 1999;159:179

LABORATORY NORMALSLABORATORY NORMALS

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

UPPER AND LOWER LIMITS OF NORMALUPPER AND LOWER LIMITS OF NORMAL

Publications on reference Publications on reference equations should include explicit equations should include explicit definitions of the upper and lower definitions of the upper and lower limits of normal range.limits of normal range.

For every functional parameter, For every functional parameter, values below the 5th percentile values below the 5th percentile of the frequency distribution of of the frequency distribution of values, measured in the values, measured in the reference equation are reference equation are considered to be below the considered to be below the expected normal range.expected normal range.

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 2000;55:172

REFERENCE EQUATIONS FOR 5th PERCENTILE

MEAN and 5th PERCENTILE in MENSAPALDIA Study conducted on 1267 men and 1890 women:

BRANDLI, O et al. Thorax 2000;55:172

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.

REFERENCE EQUATIONS FOR 5th PERCENTILE

MEAN and 5th PERCENTILE in WOMENSAPALDIA Study conducted on 1267 men and 1890 women:

TYPES OF VENTILATORY TYPES OF VENTILATORY DEFECTSDEFECTS

Obstructive abnormalitiesObstructive abnormalities

Restrictive abnormalitiesRestrictive abnormalities

Mixed abnormalitiesMixed abnormalities

OBSTRUCTIVE ABNORMALITIESOBSTRUCTIVE ABNORMALITIES

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

OBSTRUCTION in EARLY and OBSTRUCTION in EARLY and ADVANCED DISEASEADVANCED DISEASE

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

OBSTRUCTION and OTHER OBSTRUCTION and OTHER PARAMETERSPARAMETERS

Measurement of lung volumes is not mandatory to Measurement of lung volumes is not mandatory to identify an obstructive defect.identify an obstructive defect.

An increase in TLC, RV or the RV/TLC ratio above An increase in TLC, RV or the RV/TLC ratio above the upper limits of natural variability may suggest the upper limits of natural variability may suggest the presence of emphysema, asthma or the degree the presence of emphysema, asthma or the degree of lung hyperinflation.of lung hyperinflation.

Airflow resistance is more sensitive for detecting Airflow resistance is more sensitive for detecting narrowing of extrathoracic or large central narrowing of extrathoracic or large central intrathoracic airways than peripheral intrathoracic intrathoracic airways than peripheral intrathoracic airways. It may be useful in patients unable to airways. It may be useful in patients unable to perform a maximal forced expiratory manoeuvre.perform a maximal forced expiratory manoeuvre.

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

FIXED VALUES vs 5th PERCENTILEFIXED VALUES vs 5th PERCENTILE

LOWER LIMIT OF NORMALLOWER LIMIT OF NORMAL

A decrease in major spirometric parameters A decrease in major spirometric parameters such as FEV1, VC, FEV1/VC and TLC below 5th such as FEV1, VC, FEV1/VC and TLC below 5th percentile is useful in clinical practice.percentile is useful in clinical practice.

When these variables lie near the upper or lower When these variables lie near the upper or lower limits of normal; tests including bronchodilator limits of normal; tests including bronchodilator response, DLCO, gas exchange evaluation, response, DLCO, gas exchange evaluation, respiratory muscle strength or exercise testing respiratory muscle strength or exercise testing are recommended.are recommended.

GOLD2007GOLD2007PostbronkodilatorPostbronkodilator

FEV1/FVC FEV1FEV1/FVC FEV1

ERS/ATSERS/ATS

20042004FEV1/FVC FEV1FEV1/FVC FEV1

NICE NICE 20042004 FEV1FEV1

MildMild

Moderate Moderate

SevereSevere

Very Very severesevere

<% 70 <% 70 %80%80

<% 70 %50-80<% 70 %50-80

<% 70 %30-50<% 70 %30-50

<% 70 < 30<% 70 < 30

0.7 0.7 %80%80

0.7 % 50-0.7 % 50-8080

0.7 % 30-0.7 % 30-5050

0.7 <% 300.7 <% 30

% 50-80% 50-80

% 30-49% 30-49

< % 30< % 30

Hansen, J. E. et al. Chest 2007;131:349-355

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/FVC< 70% as a criterion

The GOLD guidelines misidentify one half of abnormal younger adults as normal and 1/5 of normal adults as abnormal.

Area under LLN’ın 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 1999;159:179

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

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 2006;51:737

RESTRICTIVE ABNORMALITIESRESTRICTIVE ABNORMALITIES

A restrictive ventilatory defect is A restrictive ventilatory defect is characterised by a reduction in TLC characterised by a reduction in TLC below 5th percentile of the predicted below 5th percentile of the predicted value and a normal FEV1/VC.value and a normal FEV1/VC.

Restrictive ventilatory defect should be Restrictive ventilatory defect should be suspected when VC is reduced, suspected when VC is reduced, FEV1/VC is increased(>85-90%) and FEV1/VC is increased(>85-90%) and the flow-volume curve shows a the flow-volume curve shows a convex pattern.convex pattern.

A reduced VC and a normal or slightly increased A reduced VC and a normal or slightly increased FEV1/VC is often caused by submaximal inspiratory or FEV1/VC is often caused by submaximal inspiratory or expiratory efforts and/or patchy peripheral airflow expiratory efforts and/or patchy peripheral airflow obstruction and a reduced VC itself does not mean a obstruction and a reduced VC itself does not mean a restrictive defect.restrictive defect.

Pneumothorax and noncommunicating bullae are Pneumothorax and noncommunicating bullae are characterised by a normal FEV1/VC and TLCPL but characterised by a normal FEV1/VC and TLCPL but low FEV1 and VC values. In these conditions, TLC low FEV1 and VC values. In these conditions, TLC measured by gas dilution techniques will be low.measured by gas dilution techniques will be low.

A low TLC from a single-breath test (such as VA from A low TLC from a single-breath test (such as VA from DLCO test) should not be interpreted as restriction DLCO test) should not be interpreted as restriction since such measurements underestimate TLC.since such measurements underestimate TLC.

COMMENTS ON LUNG VOLUMESCOMMENTS ON LUNG VOLUMES

Categorisation of Restrictive PatternCategorisation of Restrictive Pattern

SEVERITYSEVERITY ATS/ERS ATS/ERS 20052005

ATS ATS

19911991

MildMild

ModerateModerate

Moderately severeModerately severe

SevereSevere

Very severeVery severe

FEV1%FEV1% 70 70

FEV1% 60-69FEV1% 60-69

FEV1% 50-59FEV1% 50-59

FEV1% 35-49FEV1% 35-49

FEV1% < 35FEV1% < 35

VC % VC % 70 70

VC % < 70- VC % < 70- 60 60

VC % < 60- VC % < 60- 50 50

VC % < 50- VC % < 50- 35 35

VC % < 35VC % < 35

Venkateshiah SB. Lung 2008;186:19

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 FVC< LLN ve FEV1/FVC LLN was not so sensitive for excluding restrictive defect.

THE UTILITY OF SPIROMETRY IN ASSESSMENT OF RESTRICTION

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

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

as;as;

Ability to workAbility to work

Function in daily lifeFunction in daily life

MorbidityMorbidity

PrognosisPrognosis

CLASSIFICATION OF SEVERITYCLASSIFICATION OF SEVERITY

The severity of pulmonary function abnormalities The severity of pulmonary function abnormalities is based on FEV1 % pred. This does not apply is based on FEV1 % pred. This does not apply to upper airway obstruction. In addition, it might to upper airway obstruction. In addition, it might not be suitable for comparing different not be suitable for comparing different pulmonary diseases.pulmonary diseases.

At very severe stages of diseases FEV1 may fail At very severe stages of diseases FEV1 may fail to identify exact severity.to identify exact severity.

FEV1 % pred correlates poorly with symptoms FEV1 % pred correlates poorly with symptoms and may not accurately predict clinical severity and may not accurately predict clinical severity or prognosis.or prognosis.

Degree of SeverityDegree of Severity FEV1 % predFEV1 % pred

MildMild

ModerateModerate

Moderately severeModerately severe

SevereSevere

Very severeVery severe

7070

60-6960-69

50-5950-59

35-4935-49

<35<35

Severity of any spirometric abnormality Severity of any spirometric abnormality based on FEV1based on FEV1

ATS/ERS 2005 has recommended the severity classification of both obstruction and restriction according to FEV1.

ADDITIONAL MEASUREMENTS FOR ADDITIONAL MEASUREMENTS FOR CLASSIFICATIONCLASSIFICATION

The degree of lung hyperinflation (TLC, FRC, The degree of lung hyperinflation (TLC, FRC, RV, RV/TLC) parallels the severity of airway RV, RV/TLC) parallels the severity of airway obstruction.obstruction.Resting lung hyperinflation (IC/TLC) is an Resting lung hyperinflation (IC/TLC) is an independent predictor of respiratory and all-independent predictor of respiratory and all-cause mortality in COPD patients. cause mortality in COPD patients.

Casanova C. AJRCCM 2005;171:591Casanova C. AJRCCM 2005;171:591

Expiratory flow limitation is also related with Expiratory flow limitation is also related with increased dyspnea and cardiovascular side increased dyspnea and cardiovascular side effects. Tidal and forced expiratory flow- volume effects. Tidal and forced expiratory flow- volume curves can be compared.curves can be compared.

Milic-Emili J. AJRCCM 1996;154:1726Milic-Emili J. AJRCCM 1996;154:1726

Can severity of restriction be Can severity of restriction be classified by FEV1?classified by FEV1?

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

Aggarwal AN. Respirology 2007;12:759

BRONCHODILATOR RESPONSEBRONCHODILATOR RESPONSE

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

RECOMMENDED BRONCHODILATOR RECOMMENDED BRONCHODILATOR TESTTEST

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

INTERPRETATION OF CHANGE IN LUNG INTERPRETATION OF CHANGE IN LUNG FUNCTIONFUNCTION

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

Within a day Normal subjects 5 5 13 >7% COPD patients 11 13  23Week to week Normal subjects 11 12 21 >6 units COPD patients   20 20   30 >4 unitsYear to year 15 15 >10%

DL,COFEF25–75%FEV1FVC

ATS 1991ATS/ERS 2005

CHANGES IN PFT PARAMETERS

Year to year changes in FEV1 over 1 year should exceed 15% before being accepted as a clinically meaningful change.

CENTRAL AND UPPER AIRWAY CENTRAL AND UPPER AIRWAY OBSTRUCTIONOBSTRUCTION

Occurs in extrathoracic ( pharynx, larynx, extrathoracic Occurs in extrathoracic ( pharynx, larynx, extrathoracic portion of the trachea) and intrathoracic (intrathoracic portion of the trachea) and intrathoracic (intrathoracic trachea and main bronchi ) airways.trachea and main bronchi ) airways.

Does not lead to reduction in FEV1 and/or VC, but PEF can Does not lead to reduction in FEV1 and/or VC, but PEF can be severely affected. be severely affected.

Increased FEV1/PEF (mL.LIncreased FEV1/PEF (mL.L-1-1.min.min-1-1) ratio must alert the ) ratio must alert the clinician to the need for an inspiratory and expiratory flow-clinician to the need for an inspiratory and expiratory flow-volume loop. FEV1/PEF> 8 suggests central or upper airway volume loop. FEV1/PEF> 8 suggests central or upper airway obstruction. obstruction.

Poor initial effort can also affect this ratio. Poor initial effort can also affect this ratio. At least three maximal and repeatable flow-volume curves At least three maximal and repeatable flow-volume curves

are necessary. are necessary. ERS/ATS 2005

CENTRAL AIRWAY OBSTRUCTIONFEF50/FIF50 > 1, FEV1/FEV0.5 1.5 ERS 2003

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 > 1 < 1 1

ERS/ATS 2005