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Pulmonary function test Pulmonary function test Part IPart I

Dr.Mona AllangawiDr.Mona Allangawi

Consultant Consultant Pulmonary/AllergyPulmonary/Allergy

Hamad General Hospital - HMCHamad General Hospital - HMC

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Pulmonary function test :Pulmonary function test :Group of procedures that measure the function Group of procedures that measure the function

of the of the

lungs lungs

1.1. SpirometrySpirometry

2.2. Lung volumesLung volumes

3.3. Gas transferGas transfer

4.4. Bronchial chalenge Bronchial chalenge

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IndicationsIndications

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A.DiagnosticA.Diagnostic

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Symptoms:Symptoms:

dyspnea, wheezing, orthopnea, cough, dyspnea, wheezing, orthopnea, cough, phlegm production, chest pain phlegm production, chest pain

Signs:Signs:

decreased breath sounds, overinflation, decreased breath sounds, overinflation, expiratory slowing, cyanosis, chest expiratory slowing, cyanosis, chest deformitory, unexplained crackles deformitory, unexplained crackles

Abnormal laboratory tests:Abnormal laboratory tests:

hypoxemia, hypercapnia, hypoxemia, hypercapnia, polycythemia, abnormal chest radiographs polycythemia, abnormal chest radiographs

To measure the effect of disease on pulmonary To measure the effect of disease on pulmonary function function

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To screen individuals at risk of having To screen individuals at risk of having pulmonary diseases pulmonary diseases

1.1. Smokers Smokers 2.2. Individuals in occupations with exposures Individuals in occupations with exposures

to injurious substances to injurious substances To assess preoperative risk To assess preoperative risk To assess prognosis (lung transplant, etc.) To assess prognosis (lung transplant, etc.) To assess health status before enrollment in To assess health status before enrollment in

strenuous physical activity programs strenuous physical activity programs

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B. Monitoring B. Monitoring

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To assess therapeutic interventionsTo assess therapeutic interventions Bronchodilator therapy Bronchodilator therapy Steroid treatment for asthma, Steroid treatment for asthma,

interstitial lung disease, etc. interstitial lung disease, etc. Other (antibiotics in cystic fibrosis, Other (antibiotics in cystic fibrosis,

etc.)etc.) To monitor for adverse reactions to drugs To monitor for adverse reactions to drugs

with known pulmonary toxicitywith known pulmonary toxicity

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C. Disability/Impairment C. Disability/Impairment EvaluationsEvaluations

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To assess patients as part of a To assess patients as part of a rehabilitation program rehabilitation program Medical Medical Industrial Industrial Vocational Vocational

To assess risks as part of an insurance To assess risks as part of an insurance evaluation evaluation

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ContraindicationsContraindications

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Hemoptysis of unknown originHemoptysis of unknown origin PneumothoraxPneumothorax Unstable angina pectoris Unstable angina pectoris Recent myocardial infarctionRecent myocardial infarction Thoracic aneurysms Thoracic aneurysms Abdominal aneurysmsAbdominal aneurysms Cerebral aneurysmsCerebral aneurysms Recent eye surgery (increased intraocular Recent eye surgery (increased intraocular

pressure during forced expiration) pressure during forced expiration) Recent abdominal or thoracic surgical Recent abdominal or thoracic surgical

proceduresprocedures History of syncope associated with forced History of syncope associated with forced

exhalationexhalation

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Pulmonary function Pulmonary function test:test:

1.1. SpirometrySpirometry

2.2. Lung volumesLung volumes

3.3. Gas transferGas transfer

4.4. Bronchial chalenge Bronchial chalenge

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What is a spirometry ??What is a spirometry ??Spirometry is a measure of airflow Spirometry is a measure of airflow

andand

lung volumes during a forced lung volumes during a forced expiratoryexpiratory

maneuver from full inspiration maneuver from full inspiration

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How to do it ?? How to do it ??

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1.1. Stand or sit up straight (The patient Stand or sit up straight (The patient places a clip over the nose )places a clip over the nose )

2.2. Inhale maximallyInhale maximally3.3. Get a good seal around mouthpiece of Get a good seal around mouthpiece of

the spirometerthe spirometer4.4. Blow out as hard as fast as possible and Blow out as hard as fast as possible and

count for at least 6 seconds.count for at least 6 seconds.5.5. Record the best of three trial Record the best of three trial

*pt should hold bronchodilator few hrs before the *pt should hold bronchodilator few hrs before the test test

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1. Volume Time Graph 2. Flow-volume 1. Volume Time Graph 2. Flow-volume loopsloops

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Volume Time GraphVolume Time Graph The volume is plotted against the time, it The volume is plotted against the time, it

displays the expirationdisplays the expiration..

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1.1. FVCFVC

2.2. FEV1FEV1

3.3. FEV1/FVCFEV1/FVC

4.4. FEF25%FEF25%

5.5. FEF75%FEF75%

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Forced Vital Capacity (FVC)Forced Vital Capacity (FVC)

The total amount of air expired as The total amount of air expired as quickly as possible after taking the quickly as possible after taking the deepest possible breath. deepest possible breath.

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FEV1FEV1 ::

Volume of air which can be forcibly Volume of air which can be forcibly exhaled from the lungs in the first exhaled from the lungs in the first second of a forced expiratory second of a forced expiratory maneuver. maneuver.

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FEV1/FVC FEV1/FVC

Ratio of Ratio of FEV1FEV1 toto FVCFVC : :

It indicates what percentage of the totalIt indicates what percentage of the total FVCFVC was expelled from the lungs during was expelled from the lungs during the first second of forced exhalationthe first second of forced exhalation

This value is critically important in the This value is critically important in the diagnosis of obstructive and restrictive diagnosis of obstructive and restrictive diseasesdiseases

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FEF25%

Amount of air that was forcibly expelled in the Amount of air that was forcibly expelled in the first 25% of the total forced vital capacity test.first 25% of the total forced vital capacity test.

FEF75%FEF75%

The amount of air expelled from the lungs The amount of air expelled from the lungs during the first (75%) of the forced vital during the first (75%) of the forced vital capacity test.capacity test.

FEF25%-75%FEF25%-75%

The amount of air expelled from the lungs The amount of air expelled from the lungs during the middle half of the forced vital during the middle half of the forced vital capacity test.capacity test.

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Flow-volume loopsFlow-volume loops

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Flow-volume loopsFlow-volume loops Is a plot of inspiratory Is a plot of inspiratory

and expiratory flow in and expiratory flow in the vertical axis the vertical axis against volume in the against volume in the horizental axis, during horizental axis, during the performance of the performance of maximally forced maximally forced inspiratory and inspiratory and expiratory expiratory maneuvers. maneuvers.

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The contour of the loop assists in The contour of the loop assists in the diagnosis and localization of the diagnosis and localization of airway obstruction as different airway obstruction as different lung disorders produce lung disorders produce distinct ,easily recognized pattern.distinct ,easily recognized pattern.

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Useful also in assesing acceptability of the Useful also in assesing acceptability of the manoeuvers:manoeuvers: 1.1. Lack of early peak suggest poor effort. Lack of early peak suggest poor effort. 2. 2. Sudden tailing off of expiration curve suggest Sudden tailing off of expiration curve suggest that the patient stopped blowing too early that the patient stopped blowing too early

3. 3. Cough Cough

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Obstructive V/S restrictive lung Obstructive V/S restrictive lung disease ???disease ???

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Obstructive Lung DiseasesObstructive Lung Diseases

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Common Obstructive Lung Common Obstructive Lung DiseasesDiseases

Asthma Asthma COPD COPD (chronic bronchitis, emphysema (chronic bronchitis, emphysema

and the overlap between them).and the overlap between them). Cystic fibrosis.Cystic fibrosis.

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--Airflow is reduced because the airways narrow and the Airflow is reduced because the airways narrow and the FEV1FEV1 is reduced is reduced -Spirogram may continue to rise for more than 6 seconds -Spirogram may continue to rise for more than 6 seconds because lung take longer to empty because lung take longer to empty --FVCFVC may also be reduced because gas is trapped behind may also be reduced because gas is trapped behind obstructed bronchi due to increase in intrathoracic pressure obstructed bronchi due to increase in intrathoracic pressure during maneuver compresses airways causing early airway during maneuver compresses airways causing early airway closure and gas trapping but this reduction to a lesser extent closure and gas trapping but this reduction to a lesser extent than than FEV1FEV1

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FEV1 FEV1 ≥ 80%≥ 80% of predicted of predicted NormalNormal

FEV1 FEV1 60-80%60-80% of predicted of predicted mild obst.mild obst.

FEV1 FEV1 40-60%40-60% of predicted of predicted moderatemoderate

FEV1 ≤ FEV1 ≤ 40%40% of predicted of predicted severesevere

The cardinal feature is The cardinal feature is FEV1/FVCFEV1/FVC ratio If ratio If

the ratio less than the ratio less than 7070 consider obstructed consider obstructed

disease .disease .*Predictors: Sex, Age, Ht*Predictors: Sex, Age, Ht

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Predictors: Sex, Age, Ht ??Predictors: Sex, Age, Ht ??

The measurements are related to the following factors: The measurements are related to the following factors: AgeAge : : FVC and flow rates decline with age. The value of FVC FVC and flow rates decline with age. The value of FVC

increases up to 24 years of age and remain stable to age 35.increases up to 24 years of age and remain stable to age 35. HeightHeight :: All spirometric measurements increase with body weight. It is All spirometric measurements increase with body weight. It is

due to an increase in number and/or size of alveoli relative to due to an increase in number and/or size of alveoli relative to airways, the larger lungs are likely to take longer than smaller airways, the larger lungs are likely to take longer than smaller one. one.

SexSex : :

Most pulmonary function values are lower in female than maleMost pulmonary function values are lower in female than male. . WeightWeight : : A spirometric results are positively correlated with weight to A spirometric results are positively correlated with weight to

the extent that increased weight means growth or muscle the extent that increased weight means growth or muscle mass. Beyond this (in obesity) spirometric values (and lung mass. Beyond this (in obesity) spirometric values (and lung values specially ERV) decrease with greater weight.values specially ERV) decrease with greater weight.

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Flow volume loop in Flow volume loop in

Obstructive lung diseaseObstructive lung disease

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AsthmaAsthma

Peak expiratory flow Peak expiratory flow reduced so maximum height reduced so maximum height of the loop is reduced of the loop is reduced

Airflow reduces rapidly with Airflow reduces rapidly with the reduction in the lung the reduction in the lung volumes because the volumes because the airways narrow and the loop airways narrow and the loop become concavebecome concave

Concavity may be the Concavity may be the indicator of airflow indicator of airflow obstruction and may obstruction and may present before the change present before the change in FEV1 or FEV1/FVCin FEV1 or FEV1/FVC

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EmphysemaEmphysema

Airways may collapse Airways may collapse during forced expiration during forced expiration because of destruction of because of destruction of the supporting lung the supporting lung tissue causing very tissue causing very reduced flow at low lung reduced flow at low lung volume and a volume and a characteristic characteristic (dog-leg)(dog-leg) appearance to the flow appearance to the flow volume curvevolume curve

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Reversibility Reversibility Improvement in Improvement in FEV1 by 12-FEV1 by 12-

15% or 200 ml15% or 200 ml in repeating in repeating spirometry after treatment spirometry after treatment with Sulbutamol 2.5mg or with Sulbutamol 2.5mg or ipratrobium promide by ipratrobium promide by nebuliser after nebuliser after 15-3015-30 minutes minutes

Reversibility is a Reversibility is a characterestic feature of characterestic feature of B.Asthma B.Asthma

In chronic asthma there may In chronic asthma there may be only partial reversibility of be only partial reversibility of the airflow obstruction the airflow obstruction

While in COPD the airflow is While in COPD the airflow is irriversible although some irriversible although some cases showed significant cases showed significant improvement.improvement.

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Interpretation of PFTsInterpretation of PFTs

Step 1.Step 1. Look at the Flow-Volume loop to Look at the Flow-Volume loop to determine acceptability of the test, and look for determine acceptability of the test, and look for upper airway obstruction pattern.upper airway obstruction pattern.

Step 2.Step 2. Look at the Look at the FEV1FEV1 to determine if it is to determine if it is normal normal (≥ 80%(≥ 80% predicted). predicted).

Step 3.Step 3. Look at Look at FVCFVC to determine if it is within to determine if it is within normal limits normal limits (≥ 80%).(≥ 80%).

Step 4.Step 4. Look at Look at the the FEV1/FVC FEV1/FVC ratioratio to determine to determine if it is within normal limits if it is within normal limits (≥ 70%).(≥ 70%).

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Step 5.Step 5. Look at Look at FEF25-75%FEF25-75% (Normal (Normal (≥ 60%)(≥ 60%) If If FEV1FEV1, , FEV1/FVCFEV1/FVC ratio, and ratio, and FEF25-75%FEF25-75% all are all are

normal, the patient has a normal, the patient has a normal normal PFT.PFT.

If both If both FEV1FEV1 andand FEV1/FVCFEV1/FVC are normal, but are normal, but FEF25-75% is ≤ 60%FEF25-75% is ≤ 60% ,then think about early ,then think about early obstruction or small airways obstruction.obstruction or small airways obstruction.

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If If FEV1 FEV1 ≤ 80% and ≤ 80% and FEV1/FVC FEV1/FVC ≤ 70%, there is ≤ 70%, there is obstructive defect, if obstructive defect, if FVCFVC is normal, it is pure is normal, it is pure obstruction. If obstruction. If FVC FVC ≤ 80% , possibility of ≤ 80% , possibility of additional restriction is there.additional restriction is there.

If If FEV1 FEV1 ≤ 80% , ≤ 80% , FVC FVC ≤ 80% and ≤ 80% and FEV1/FVC FEV1/FVC ≥ ≥ 70%70% , there is restrictive defect, get lung , there is restrictive defect, get lung volumes to confirm. volumes to confirm.

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ExamplesExamples

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• Mild Obstructive Defect with good response to Mild Obstructive Defect with good response to

bronchodilatorbronchodilator

Diagnosis:Diagnosis:

B.AsthmaB.Asthma

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A 66 year old female complains A 66 year old female complains

of cough after dust exposureof cough after dust exposure

MeasMeasRefRef%%PredPred

FVCFVC2.22.22.582.588585

FEV1FEV11.791.791.851.859797

FEV1/FVCFEV1/FVC81817272

FEF 25-75FEF 25-751.821.822.232.238282

PEFPEF5.675.675.25.2109109

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Normal SpirometryNormal Spirometry

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• Flow volume loop suggestive of obstructive Flow volume loop suggestive of obstructive diseasedisease

• Spirometry showed Severe Obstructive defect Spirometry showed Severe Obstructive defect with no response to bronchodilatorwith no response to bronchodilator

• Increased FVC could be because of Airtrapping Increased FVC could be because of Airtrapping or could be combined obstructive and restrictive or could be combined obstructive and restrictive defect to confirm need to do Lung Volumedefect to confirm need to do Lung Volume

diagnosis :diagnosis :

COPD COPD

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A 75 year old female has a history A 75 year old female has a history of dyspnea and palpitationsof dyspnea and palpitations

MeasMeasRefRef%%PredPred

FVCFVC2.622.622.822.829393

FEV1FEV11.451.451.981.987272

FEV1/FVCFEV1/FVC55556969

FEF25-75FEF25-750.430.432.202.202020

PEFPEF4.504.505.485.488282

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Mild Obstructive defectMild Obstructive defect

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Large Airway Obstruction Large Airway Obstruction

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1. 1. Fixed obstructionFixed obstruction

2. 2. Variable extrathoracicVariable extrathoracic obstructionobstruction

3. 3. Variable intrathoracic obstructionVariable intrathoracic obstruction

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Flow Volume Loop in Flow Volume Loop in

Large Airway Obstruction Large Airway Obstruction

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Fixed obstructionFixed obstruction1. Post intubation stenosis 1. Post intubation stenosis

2. Goiter2. Goiter

3. Endotracheal 3. Endotracheal neoplasmsneoplasms

4. Bronchial stenosis 4. Bronchial stenosis

Maximum airflow is Maximum airflow is limited to a similar limited to a similar extent in both extent in both inspinspiration and iration and expexpirationiration

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Variable Variable extrextrathoracicathoracic

ObstructionObstruction1. Bilateral and unilateral vocal 1. Bilateral and unilateral vocal

cord paralysiscord paralysis

2. Vocal cord constriction 2. Vocal cord constriction

3. Reduced pharyngeal cross-3. Reduced pharyngeal cross-sectional area sectional area

4. Airway burns4. Airway burns

The obstruction worsens in The obstruction worsens in inspinspiration because the iration because the negative pressure narrows negative pressure narrows the trachea and the trachea and inspiratory flow is reduced inspiratory flow is reduced to a greater extent than to a greater extent than expiratory flow expiratory flow

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In variable In variable intrintrathoracic athoracic

obstructionobstruction

1. 1. Tracheomalacia Tracheomalacia

2. Polychondritis2. Polychondritis

3. Tumors of the lower trachea or 3. Tumors of the lower trachea or main bronchus. main bronchus.

The narrowing is maximal in The narrowing is maximal in expexpiration because of iration because of increased intrathoracic increased intrathoracic pressure compressing the pressure compressing the airway.airway.

The flow volume loop shows a The flow volume loop shows a greater reduction in the greater reduction in the expiratoryexpiratory phase phase

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Small Airways obstructionSmall Airways obstruction

Diseases affecting primarily the small Diseases affecting primarily the small (peripheral) airways can be extensive yet not (peripheral) airways can be extensive yet not affect the FEV1(e.g. early COPD, interstitial affect the FEV1(e.g. early COPD, interstitial granulomatous disorders).granulomatous disorders).

Small airways status is reflected by the FEF25-Small airways status is reflected by the FEF25-75% (mid-range flow), best determined from 75% (mid-range flow), best determined from the flow-volume loop.the flow-volume loop.

Some patients have normal spirometry with the Some patients have normal spirometry with the exception of a reduced FEF25-75%, this is exception of a reduced FEF25-75%, this is suggestive of possible small airways suggestive of possible small airways dysfunction and potentially early obstruction.dysfunction and potentially early obstruction.

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ExampleExample

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A 38 year old female complains A 38 year old female complains of wheezing on exertionof wheezing on exertion

MeasMeasRefRef%%PrPr

eedd

FVCFVC3.663.663.543.54103103

FEV1FEV12.302.302.772.778383

FEV1/FVCFEV1/FVC63637878

FEF25-75FEF25-752.152.154.204.205151

PEFPEF2.392.396.256.253838

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Flow volume loop suggests a fixed Flow volume loop suggests a fixed upper airway obstructionupper airway obstruction

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Effect of Smoking:Effect of Smoking: Smoking in patients with COPD is Smoking in patients with COPD is

associated with decline in associated with decline in FEV1 of 90-FEV1 of 90-150 mL/year150 mL/year

Smoking cessation is (associated with Smoking cessation is (associated with

increase in increase in FEV1FEV1 for first year) followed for first year) followed with a decline of only 30 mL/year with a decline of only 30 mL/year

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Restrictive Lung Diseases Restrictive Lung Diseases

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A. Intrinsic Restrictive Lung A. Intrinsic Restrictive Lung DisordersDisorders

1.1. SarcoidosisSarcoidosis

2.2. Idiopathic pulmonary fibrosisIdiopathic pulmonary fibrosis

3.3. Interstitial pneumonitis Interstitial pneumonitis

4.4. Tuberculosis Tuberculosis

5.5. Pnuemonectomy (loss of lung)Pnuemonectomy (loss of lung)

6.6. Pneumonia Pneumonia

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B. B. Extrinsic Restrictive Lung DisordersExtrinsic Restrictive Lung Disorders

1.1. Scoliosis, KyphosisScoliosis, Kyphosis

2.2. Ankylosing SpondylitisAnkylosing Spondylitis

3.3. Pleural EffusionPleural Effusion

4.4. PregnancyPregnancy

5.5. Gross ObesityGross Obesity

6.6. TumorsTumors

7.7. AscitesAscites

8.8. Pain on inspiration - pleurisy, rib fracturesPain on inspiration - pleurisy, rib fractures

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C.C. Neuromuscular Restrictive Lung Neuromuscular Restrictive Lung DisordersDisorders

1.1. Generalized Weakness – malnutritionGeneralized Weakness – malnutrition

2.2. Paralysis of the diaphragmParalysis of the diaphragm

3.3. Myasthenia Gravis Myasthenia Gravis

4.4. Muscular DystrophyMuscular Dystrophy

5.5. PoliomyelitisPoliomyelitis

6.6. Amyotrophic Lateral Sclerosis Amyotrophic Lateral Sclerosis

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Full expantion of the Full expantion of the lung is limited and lung is limited and therefore the therefore the FVCFVC is is reduced reduced

FEV1FEV1 may be reduced may be reduced because the stiffness of because the stiffness of fibrotic lungs increases fibrotic lungs increases the expiratory pressure the expiratory pressure

FEV1/FVCFEV1/FVC will be Normal will be Normal or Increasedor Increased

*if you suspect restrictive *if you suspect restrictive pattern you must check pattern you must check TLCTLC

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Flow volume loop in Flow volume loop in

Restrictive lung disease Restrictive lung disease

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Flow volume loop in Flow volume loop in Restrictive lung diseaseRestrictive lung disease ::

Full lung expantion is Full lung expantion is prevented by fibrotic tissue prevented by fibrotic tissue in the lung parenchyma and in the lung parenchyma and thethe FVC FVC is reduced . is reduced .

Elastic recoil may increased Elastic recoil may increased by fibrotic tissue lead to by fibrotic tissue lead to increase the airflow increase the airflow

Both Both FEV1FEV1 and and FVCFVC may be may be reduced because the lungs reduced because the lungs are small and stiff ,but the are small and stiff ,but the peak expiratory flow may be peak expiratory flow may be preserved or even higher preserved or even higher than predicted leads to than predicted leads to tall,narrow and steep flow tall,narrow and steep flow volume loop in expiratory volume loop in expiratory phase.phase.

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ExampleExample

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• Mild restrictive defect suggested by reduced in Mild restrictive defect suggested by reduced in FVC with normal to high FEV1/FVCFVC with normal to high FEV1/FVC

• Need lung volume and diffusion capacity to Need lung volume and diffusion capacity to assess if it is intrinsic or extrinsic typeassess if it is intrinsic or extrinsic type

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Obstructive & restrictive defectsObstructive & restrictive defects

ParametParameterer

ObstructioObstructionn

RestrictioRestrictionn

FEV1FEV1ReducedReducedReducedReduced

FVCFVCNormalNormalReducedReduced

FEV1/FEV1/FVCFVC

ReducedReducedNormalNormal

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Acceptability and Acceptability and Reproducibility CriteriaReproducibility Criteria

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Acceptability CriteriaAcceptability Criteria

free from artifacts:free from artifacts:   Cough or glottis closure during the first Cough or glottis closure during the first

second of exhalationsecond of exhalation Eary termination or cutoffEary termination or cutoff Variable effortVariable effort LeakLeak Obstructed mouthpieceObstructed mouthpiece   Have good startsHave good starts Have a satisfactory exhalation 6 s of Have a satisfactory exhalation 6 s of

exhalationexhalation

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Reproducibility CriteriaReproducibility CriteriaAfter 3 acceptable spirograms been obtainedAfter 3 acceptable spirograms been obtained Are the two largest FVC within 0.2 L of each other?Are the two largest FVC within 0.2 L of each other?

Are the two largest FEV1 within 0.2 L of each Are the two largest FEV1 within 0.2 L of each other?other?

If both of these criteria are met, the test session If both of these criteria are met, the test session

may be concluded.may be concluded. If both of these criteria are not met, continue If both of these criteria are not met, continue

testing until Both of the criteria are met with testing until Both of the criteria are met with analysis of additional acceptable spirograms; OR a analysis of additional acceptable spirograms; OR a total of eight tests have been performedtotal of eight tests have been performed

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Acceptability of the testAcceptability of the test

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Early Glottic ClosureNormal

Poor EffortCough

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ExampleExample

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1.What is the defect?1.What is the defect?

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Mild obstructive defect with good Mild obstructive defect with good response to bronchodilatorresponse to bronchodilator

DiagnosisDiagnosis

B.AsthmaB.Asthma