1、Respiratory Department of the Second Affiliated Hospital of Guangzhou Medical University Huaxing Huang History of pulmonary function testingnMore than 300 years,water sealed spirometer wedged-typed spirometer drum-typed spirometer digitalized spirometernIn 1679,BORELLI measured lung volume firstly.n
2、In 1846,HUTCHINSON put forward the concept of vital capacity.nIn 1919,NIANSTROHL put forward the concept of forced vital capacity.nIn 1967,DOLLFUSS put forward the concept of disease of small airway.nIn 1979,ATS setup the work standards of pulmonary function testing.Clinical Pratice of Pulmonary Fun
3、ction TestingnDiagnosticnObjective AssessmentnMonitoringnEvaluations for Disability/ImpairmentLung volume and capacityVentilation functionDiffusion functionMechanics of breathingMain Programs of Pulmonary Function TestingLung volumenLung volume means the maximal volume of gas contained by a lung.nLu
4、ng volume=tidal volume(VT)+inspiratory reserve volume(IRV)+expiratory reserve volume(ERV)+residual volume(RV)nLung capacity:inspiratory capacity(IC),vital capacity(VC),functional residual capacity(FRV),total lung capacity(TLC)Curve of lung capacityIRVERVVTVCRVTLCICFRCVital capacity The maximum volum
5、e of air that can be inspired by forceful expiration.Residual volumeInspiratory reserve volume Expiratory reserve capacityTotal lung capacity Tidal volume Functional reserve volumeTidal volume(VT)nThe volume of air inspired or expired with each normal breath.n8-15ML/KG Inspiratory capacity（IC）Inspir
6、atory reserve volume（IRV）nIC,the maximum volume of air that can be inspired by forceful expiration.It is equal to VT plus IRV.nIRV,the maximum extra volume of air that be inspired over and above the normal tidal volume.nThese reveal the maximam expansion of lung and chest at static state.Expiratory
7、reserve volume(ERV）nThe maximum extra volume of air that be inspired over and above the normal tidal volume.nIt reflects the power of expiratory muscle and abdominal muscle.Vital capacity（VC）nThe largest amount of air that can be expired after a maximal inspiratory effort frequently.nVC varies among
8、 normal bodies,so ratios of measured VC to predicted VC are used for judgment.nGrading standard：ratio of measured VC to predicted VC 80%normal 60-79%mildly reduced 40-59%moderately reduced FRC%Pred 120%increased FRCn10L hyperventilationnMV3L hypoventilation Alveolar ventilation(VA)nThe amount of air
9、 reaching the alveoli per minute at rest.nAnatomic dead space:the space in the conducing zone of the airways occupied by gas that does not exchange with blood in the pulmonary vessels,such as the space in nose and pharynx.nAlveolar dead space:some of the alveoli themselves are nonfunctional or only
10、partially functional because of absent or poor blood flow through adjacent pulmonary capillaries.nPhysiological dead space（VD）=Anatomic dead space+Alveolar dead space.nVA=（MVVD）RRVA varies in bodies and ranges from 3 to 5.5L.VA reflects the effective ventilation.Reduction of MVV and increased dead s
11、pace will result in alveolar hypo-ventilation.Dead space that results from deep and slow breathing is less than that of shallow and rapid breathing.So less respiratory rate and more VT will be better for VA.Alveolar ventilation(VA)Maximal volumtary ventilation（MVV）nThe total amount of new air moved
12、into the respiratory passages by deepest and faster breathing in each minute.It depends on lung volume,compliance of lung and thorax,airway resistance and respiratory muscle.n MVV%Pred 80%normal nDamage grading：MVV%Pred 60-79%mildly reduced 40-59%moderately reduced 40%severely reduced Increased airw
13、ay resistance:asthma Thoracic deformity or neuromuscular diseases:kyphoscoliosis,Guillian-Barre syndrome Diseases of lung tissue：pulmonary edema Main causes of reduced MVVTimed Vital Capacity(TVC)nFEV1nFEV1Timed Vital Capacity(TVC)nFVC(forced vital capacity):This is the amount of air expelled from t
14、he lungs after first filling the lungs to maximum extent and then expiring rapidly and forcefully.nFEV1(forced expiratory volume in one second)is the amount that can be got in the first second when FVC is measured.Timed Vital Capacity(TVC)nMMEF(maximal mid-expiratory)：After FVC divided into four ave
15、rage parts,divide the amount of the two middle parts by the corresponding expiratory time,MMEF will be got.Timed Vital Capacity(TVC)FVC%Pred 80%FEV1%Pred 80%FEV1/FVC 70%-80%FEV1%Pred can be used to evaluate the damage degree of ventilation and differentiate obstructive ventilation dysfunction from r
16、estrictive ventilation dysfunction.TimeVolume curvetime（s）0 1 2 3 4 5abcVolume(l)FEV1 FVCRVTLCSVC FVCnormalrestrictiveobstructive Clinical SignificancenIn normal body,FVC is closed to VC.Increased intrapleural pressure makes small airway close in earlier stage of expiration.At this situation,FVC is
17、less than VC.It happens to patients with COPD.nEvaluate ventilation dysfunction：obstructive diseases:FEV1/FVC%reduced,flat curve restrictive diseases:FEV1/FVC%normal or increased,gradient curveGrading Classification of Ventilation Function in COPD(bronchial dilator used)levelFEV1/FVCFEV%PredI70%80%I
18、I70%50%FEV%Pred 80%III70%30%FEV%Pred50%IV70%30%or50%,chronic respiratory failurePEF(peak expiratory flow)nThe maximal flow during a forceful expiration.PEF should be measured in the morning,afternoon and before sleeping.PEFR=（PEFmaximum-PEFminimum)2 PEFmaximum+PEFminimumnPEF help to evaluate the cha
19、ge of airway resistance.100%Classification of ventilation dysfunctionnObstructive ventilation dysfunctionnRestrictive ventilation dysfunctionnMixed ventilation dysfunctionCharacteristics of ventilation dysfunctionobstructiverestrictivemixedLung capacityVCN or FRC unsureTLCN or unsureRV/TLCunsureunsu
20、reobstructiverestrictivemixedFEV1 FEV1/FVC N orN orMVV MMEF Characteristics of ventilation dysfunctionDiffusion functionnGas exchange function means the course of gas exchange,including the exchange of O2 and CO2 between alveolus and blood,blood and histocyte.It involves lung ventilation,blood perfu
21、sion,ventilation-perfusion ratio and diffusion function.nDiffusion function can be measured to evaluate gas exchange function to some extent.Diffusion functionnThe gas exchange between alveolus and blood capillary from the high partial pressure side to the low side.nRelative factors:molecular weight
22、,solubility,gas partial pressure gradient,diffusion area,diffusion distance.Gas ExchangePO2104 mm HgPCO240 mm HgPO2104 mm HgPCO240 mm HgPO240 mm HgPCO245 mm Hg Clinical significance Factors that can reduce the capacity of diffusion:nReduced effective diffusion area:atelectasis,airway obstruction,pul
23、monary embolismn Increased diffusion distance:PIF,pulmonary edema,sarcoidosis,alveolar cell carcinomanThe capacity of diffusion also depends on gas partial pressure.FlowVolume curve(F-V loop)nIts a record about the course that take a rapid expiration to the extent of RV after a maximal inspiration t
24、o the extent of TLC.nThe flow rises rapidly at the beginning of forceful expiration and reaches the point of PEF soon.With the reduction of VC,the flow goes down perpendicularly almost.n IC VC IRV VTERVPEFvmax75.vmax50.vmax25.PEF and Vmax75 reflect the main airway resistance and respiratory muscle s
25、trength.Vmax50 and Vmax25 reflect small airway resistance.Descending branch sinks to the volume axis in obstructive diseases,but VC may not reduce.In restrictive diseases,the curves rise sharply and the descending branches sink nearly perpendicularly.They have reduced VC.FlowVolume curve(F-V loop)fl
26、owvolumeTypes of FlowVolume curves of Different Ventilation DysfunctionRVTLC normalobstructiverestrictivemixedflowvolumeexpirationinspirationUnilateral vocal cord paralysisflowvolumeexpirationinspirationflowvolumeexpirationinspirationAirway Reactivity TESTnBronchial provocation testnBronchial dilati
27、on testnFEV1 is used to identify the existence of airway obstruction and grade the degree of reversibility.Bronchial provocation testnIt includes direct bronchial provocation test and indirect bronchial provocation test.nCommon inspiratory activator:nonspecific activator:histamine phosphate,methacholine specific activator:pollen,dust mite Bronchial dilation testnFEV1 improvement rate=（FEV1(after medication)FEV1(before medication)）/FEV1(before medication)nBronchial dilation test(+):FEV1 improvement rate 12%and FEV1increase more than 200mlThank you！
