Thorax (1959), 14, 286. TERMINOLOGY, DEFINITIONS, AND CLASSIFICATION OF CHRONIC PULMONARY EMPHYSEMA AND RELATED CONDITIONS A REPORT OF THE CONCLUSIONS OF A CIBA GUEST SYMPOSIUM* PURPOSE AND TERMS OF REFERENCE OF THE SYMPOSIUM At present the word emphysema is used to indicate various morbid states of the lung differing widely in their pathology, symptomatology, and prognosis. This results in confusion and mis- understanding between investigators working in different centres and in different branches of medicine and thus retards advance in knowledge of a group of common and often serious disabling diseases. The purpose of the symposium, the conclusions of which are reported here, was to see whether a group of British investigators could agree upon provisional definitions, classifications, and terminology, and suggest lines of investigation which might clarify obscurities which at present impede the formulation of a satisfactory system of classification. Individual contributions to the symposium were presented informally and were not intended for publication. At the end of the meeting certain provisional conclusions and proposals were formulated. These were subsequently recon- sidered, modified by a drafting committee, and finally approved (with minor reservations) by all the participants. The proposals are provisional and should not be regarded as committing any of the participants to any particular view. They are published in order to encourage people to use defined terms in making pathological, clinical, and functional assessments, to investigate the reproducibility of these assessments in the hands of the same and different observers, and to determine their significance and validity by comparing the results of the different types of assessment with one another. The participants thought this was necessary before any final definition or classification of emphysema itself or the conditions that may be associated with it could *The symposium was held on September 24-26, 1958. A list of the participants is given in the Appendix. The report was prepared by Dr. C. M. Fletcher with the assistance of a drafting committee consisting of Dr. J. G. Gilson. Dr. P. Hugh-Jones. and Dr. J. G. Scadding. Reprints are obtainable from Dr. C. M. Fletcher, Post- graduate Medical School of London, Ducane Road, London, W.12. be elaborated. It is hoped that further investiga- tions may be assisted by the suggestions put forward, and that in the light of this research what is found useful may become more widely used, and what is imperfect or incorrect may be revealed and corrected. GENERAL PRINCIPLES OF DEFINITION lN RELATION TO EMPHYSEMAt A disease, as a general concept, may be defined as those abnormal phenomena observed in a group of organisms with disturbed function or structure, the group being defined in a stated way. There are four principal ways in which such a group may be defined: clinical, i.e., upon a simple descriptive basis; morbid anatomical; functional or physiological; or aetiological. The term emphysema indicates, and was originally applied by Laennec to, a morbid anatomical state. It is, therefore, appropriate to define it in anatomical terms. When this has been done it has not been found possible to correlate emphysema with any single uniform clinical, radiological, or functional syndrome. It is, therefore, necessary to attempt to define and designate in clinical, radiological, or functional terms syndromes which are thought to be associated with emphysema, and then to study the relation of these syndromes to various morbid anatomical changes. Only when this has been done will it be known whether it is possible to define combined clinico-pathological syndromes to which the word emphysema may justifiably be applied. Meanwhile it is suggested that only clinical and functional terms should be used to describe and define clinical and functional syndromes. The clinical use of the word emphysema should be regarded as presumptive and should only be applied to those cases in which, in the observer's opinion, the defined morbid anatomical changes of emphysema can confidently be asserted to be present. It should be noted that this procedure works well in the field tSee Scadding (1959) for a full presentation of these principles. on July 27, 2020 by guest. Protected by copyright. http://thorax.bmj.com/ Thorax: first published as 10.1136/thx.14.4.286 on 1 December 1959. Downloaded from
Transcript
Thorax (1959), 14, 286.
TERMINOLOGY, DEFINITIONS, AND CLASSIFICATION OFCHRONIC PULMONARY EMPHYSEMA AND
RELATED CONDITIONSA REPORT OF THE CONCLUSIONS OF A CIBA GUEST SYMPOSIUM*
PURPOSE AND TERMS OF REFERENCEOF THE SYMPOSIUM
At present the word emphysema is used toindicate various morbid states of the lung differingwidely in their pathology, symptomatology, andprognosis. This results in confusion and mis-understanding between investigators working indifferent centres and in different branches ofmedicine and thus retards advance in knowledgeof a group of common and often serious disablingdiseases.The purpose of the symposium, the conclusions
of which are reported here, was to see whether agroup of British investigators could agree uponprovisional definitions, classifications, andterminology, and suggest lines of investigationwhich might clarify obscurities which at presentimpede the formulation of a satisfactory systemof classification.
Individual contributions to the symposium werepresented informally and were not intended forpublication. At the end of the meeting certainprovisional conclusions and proposals wereformulated. These were subsequently recon-sidered, modified by a drafting committee, andfinally approved (with minor reservations) by allthe participants. The proposals are provisionaland should not be regarded as committing any ofthe participants to any particular view. They arepublished in order to encourage people to usedefined terms in making pathological, clinical,and functional assessments, to investigate thereproducibility of these assessments in the handsof the same and different observers, and todetermine their significance and validity bycomparing the results of the different types ofassessment with one another. The participantsthought this was necessary before any finaldefinition or classification of emphysema itself orthe conditions that may be associated with it could*The symposium was held on September 24-26, 1958. A list of
the participants is given in the Appendix. The report was preparedby Dr. C. M. Fletcher with the assistance of a drafting committeeconsisting of Dr. J. G. Gilson. Dr. P. Hugh-Jones. and Dr. J. G.Scadding. Reprints are obtainable from Dr. C. M. Fletcher, Post-graduate Medical School of London, Ducane Road, London, W.12.
be elaborated. It is hoped that further investiga-tions may be assisted by the suggestions putforward, and that in the light of this research whatis found useful may become more widely used,and what is imperfect or incorrect may berevealed and corrected.
GENERAL PRINCIPLES OF DEFINITION lNRELATION TO EMPHYSEMAt
A disease, as a general concept, may be definedas those abnormal phenomena observed in agroup of organisms with disturbed function orstructure, the group being defined in a stated way.There are four principal ways in which such agroup may be defined: clinical, i.e., upon a simpledescriptive basis; morbid anatomical; functionalor physiological; or aetiological.The term emphysema indicates, and was
originally applied by Laennec to, a morbidanatomical state. It is, therefore, appropriateto define it in anatomical terms. When this hasbeen done it has not been found possible tocorrelate emphysema with any single uniformclinical, radiological, or functional syndrome. Itis, therefore, necessary to attempt to define anddesignate in clinical, radiological, or functionalterms syndromes which are thought to beassociated with emphysema, and then to study therelation of these syndromes to various morbidanatomical changes. Only when this has beendone will it be known whether it is possible todefine combined clinico-pathological syndromesto which the word emphysema may justifiably beapplied. Meanwhile it is suggested that onlyclinical and functional terms should be used todescribe and define clinical and functionalsyndromes. The clinical use of the wordemphysema should be regarded as presumptiveand should only be applied to those cases inwhich, in the observer's opinion, the definedmorbid anatomical changes of emphysema canconfidently be asserted to be present. It should benoted that this procedure works well in the field
tSee Scadding (1959) for a full presentation of these principles.
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of cardiology, where the functional changesof circulatory failure are defined and classifiedseparately from the morbid anatomical conditionsthat may cause them.
RECOMMENDATIONS FOR PATHOLOGICALDEFINITION AND CLASSIFICATION
OF EMPHYSEMADEFINITION OF EMPHYSEMA
"Emphysema is a condition of the lungcharacterized by increase beyond the normal inthe size of air spaces distal to the terminalbronchiole either from dilatation or fromdestruction of their walls."Emphysema can be diagnosed and classified
consistently only on preparations from lungsdistended and fixed before they are cut. Thesimplest technique is intrabronchial infusion offixative. In some cases identification of theanatomical origin of enlarged spaces may requiresuch techniques as the study of serial sections, orstereoscopic microscopy of lung slices.
It will be necessary to establish the normalrange of sizes of air spaces according to age andsex by each technique of lung preparation inorder to establish the upper limits of normal size.The term emphysema is restricted to dilatation
of air spaces distal to the terminal bronchiole inorder to differentiate emphysema from dilatationwhich includes structures proximal to the terminalbronchiole, as in various forms of honeycomblung.
CLASSIFICATION OF EMPHYSEMAA classification is proposed upon a descriptive
morbid anatomical basis, since too little is knownabout pathogenesis to justify a formal patho-genetic basis. The classification depends uponthe distribution of changes within the acinus(defined here as the unit of broncho-pulmonarytissue distal to each terminal bronchiole), and uponthe absence or presence of destruction of the wallsof air spaces.There is some difference of opinion as to which
of these grounds for separation should be primary.The majority of pathologists at the symposiumpreferred to make the primary division accordingto distribution, since this was believed to indicate adifference of pathogenesis, and this is how theclassification is first presented below.An alternative arrangement is also given. This
was preferred by one pathologist (L.McA.R.)and the majority of clinicians, because it maybetter match the clinical differentiation betweenpotentially reversible and irreversible groups, and
suggests an alternative pathogenesis. The actualtypes of emphysema which are to be distinguishedare the same according to either arrangement.
1. Unselective distribution beyond the terminalbronchiole (panacinar emphysema).
(a) Dilatation alone (e.g., compensatoryemphysema and emphysema due to partial mainbronchus obstruction).
(b) Destruction of the walls of air spaces(panacinar destructive emphysema).
2. Selective distribution beyond the terminalbronchiole.
(b) Destruction of the walls of air spaces(centrilobular emphysema).
(ii) Predominantly affecting alveolar ducts andsacs.
(a) Dilatation alone.(b) Destruction.3. Irregular distribution beyond the terminal
bronchiole (irregular emphysema).The following alternative arrangement of the
classification was proposed.1. Dilatation alone.(a) Unselective distribution (compensatory
emphysema and emphysema due to partial mainbronchus obstruction).
(b) Selective distribution predominantly affect-ing respiratory bronchioles (e.g., focal emphysemadue to dust).
2. Destruction of the walls of air spaces.(a) Unselective distribution (panacinar
destructive emphysema).(b) Selective distribution predominantly affect-
ing respiratory bronchioles (centrilobularemphysema).
(c) Irregular distribution (irregular emphysema).(Subgroups with selective distribution pre-dominantly affecting alveolar ducts and sacs areomitted from this arrangement because those whofavoured it did not recognize their existence. Iflater experience shows them to exist, they can beinserted in the appropriate positions under 1 (b)and 2 (b).)
It was difficult to decide on the most appropri-ate word to describe unselective distribution ofemphysema within the acinus. The words" diffuse " and " generalized" have been used inthis sense, but both were rejected because theycould be taken to imply widespread distribution
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throughout the lung. The word " panacinar " wasintroduced to replace these in so far as they referto emphysema which involves all air spacesbeyond the terminal bronchiole more or lessuniformly.The word " irregular " is introduced to describe
the type of emphysema, commonly found in theneighbourhood of scars, in which dilatation anddestruction of air spaces affects neither uniformlynor predominantly one section of the acini.
It is suggested that the word " widespread"should be used to indicate that emphysema of anytype is widely distributed throughout the lung.Conversely the word " localized " should be usedto indicate that emphysema of any type isconfined to one or more segments or lobes of thelung.Panacinar dilatation emphysema includes such
conditions as emphysema compensatory toshrinkage of other parts of the lung, andemphysema due to partial obstruction of air flowanywhere from the larynx to the bronchioles.The adjective " obstructive " should not be usedto qualify emphysema unless the presence ofbronchial obstruction and its relation (aetiologicaland anatomical) to the emphysema can bedemonstrated.
It was agreed that the use of the term " focalemphysema" to refer specifically to the changesdue to focal deposition of dust was so wellestablished that this name should be retained.This appears to represent the only recognizedform of dilatation emphysema predominantlyaffecting the respiratory bronchioles. Similarly,the term "centrilobular emphysema" is wellestablished and could continue to be used asa synonym for destruction emphysema pre-dominantly affecting the more proximal parts ofthe acini.The word " vesicular " was used by Laennec to
distinguish the types of emphysema which we havedefined from " interlobular " emphysema, whichis now generally called " interstitial." If the wordemphysema is used without qualification it shouldbe assumed to refer to the vesicular, not to theinterstitial, variety.The words " bulla," "cyst," and " bleb " often
appear to be used interchangeably, except thatan air space lined by recognizable bronchialepithelium or by a fibrous wall is referred to as acyst, and " bleb " indicates a collection of airbetween the layers of the visceral pleura. It issuggested that a bulla should be defined as anemphysematous space with a diameter of morethan 1 cm. in the distended state. Bullae may
accompany any sort of destruction emphysemaand their presence should be separately noted.The term " senile emphysema " does not appear
to have been applied to any distinguishable typeof disease. Its use is not recommended. Whenthe normal range of size of air spaces in the lungat different ages has been established, the use ofthe term should be reconsidered.
GRADING OF SEVERITY OF EMPHYSEMAIt is necessary to have some means of grading
the severity of emphysema for comparativestudies and for correlation with clinical andphysiological observations. In cases with wide-spread emphysema, the ideal method would be totake random samples of an agreed size from bothlungs after distension and fixation and to grade theseverity of the disease on the average of thcfindings in these samples. Since this is imprac-ticable, it is proposed that the changes in eachlobe should be graded from 0 to 3 (i.e., absent,mild, moderate, and severe). This grading shouldbe based on an estimate of the average severitywithin each lobe. For simplicity, it is suggestedthat the right middle lobe should be included aspart of the right upper lobe, thus making twolobes on each side for grading purposes. In casesof focal and centrilobular emphysema, assessmentof the severity should be based chiefly on theamount of respiratory tissue affected by theemphysema. In mild cases less than 25%, inmoderate cases 25% to 50%, and in severe casesmore than 50% of the lung should be abnormal.Examples are given in the illustrations. Inpanacinar emphysema the size of the air spaces isthe main consideration in grading, which shouldbe done to conform as closely as possible with theexamples shown in the illustrations. If desired,the overall severity can then be expressed as thesum of the grades in each lobe divided by four.The predominant type of emphysema in eachlobe should be noted. The presence of bullae andother important broncho-pulmonary and vascularabnormalities should be separately recorded.The illustrations of the different types of
emphysema in different grades of severity givenin Figs. 1 to 12 may assist in classification andgrading. They have been produced by twomethods. Figs. 1, 2, 7, 8, 9, and 10 are photo-graphs of whole lung sections mounted on paperby the method of Gough and Wentworth (1949),and Figs. 3, 4, 5, 6, 11, and 12 are photographsof slices of lung distended and impregnated withbarium sulphate by the method of Heard (1958).Figs. 1 and 2 show respectively the upper limit of
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the mild grade and the lower limit of the severegrade of panacinar emphysema in paper-mountedsections. Fig. 3 is a normal lung, and Figs. 4, 5,and 6 lungs with mild, moderate, and severepanacinar emphysema prepared by bariumsulphate impregnation. Figs. 7 and 8 showrespectively the upper limit of the mild grade andthe lower limit of the severe grade of focalemphysema in paper-mounted sections. Figs. 9and 10, also prepared by this method, and Figs. 11and 12, prepared by barium sulphate impregna-tion, show similar grades of centrilobularemphysema.
This method of grading will require studies ofits reproducibility in the hands of differentpathologists and of its validity in relation toclinical and functional studies before it can beaccepted, but a start must be made towards aquantitative estimate of severity of emphysemaand it is hoped that these proposals may providesuch a starting point.
RECOMMENDATIONS FOR CLINICALDEFINITIONS, CLASSIFICATION, AND
CODINGAt present the diagnoses " chronic bronchitis,"
" asthma," and " emphysema " are used withoutany general agreement about the clinical condi-tions to which they refer. Any one (or more) ofthese words may be used by different clinicians todescribe the condition of the same patient. Itappears that chronic bronchitis is often used inGreat Britain to describe cases that would becalled asthma or emphysema in the United States.These conditions together constitute a group of
chronic non-specific lung diseases (accepting thebronchial tree as part of the lung) with whosedefinition and classification we are hereconcerned.The name " chronic non-specific lung disease"
is suggested for the whole group. This cumber-some phrase will seldom be used in clinicalpractice, for patients will usually be allocated toone of the classes designated and defined below.
DEFINITION OF CHRONIC NON-SPECIFICLUNG DISEASE
The group as a whole may be defined as com-prising those subjects with one or more of thefollowing: chronic cough with expectoration, andparoxysmal or persistent excessive breathlessness,which are not solely attributable to:
(a) Localized lung disease of any kind (e.g.,tuberculosis, pneumonia, bronchiectasis, cysticdisease).
(b) Generalized specific infective lung diseases(e.g., miliary tuberculosis).
(c) The pneumoconioses.(d) Collagen diseases and the generalized
pulmonary fibroses and granulomata.(e) Primary cardiovascular-renal diseases.(f) Diseases of the chest wall.(g) Psychoneurosis.Chronic non-specific lung disease may coexist
with any of the diseases referred to above. Forinstance, in a case of healed tuberculosis or ofsimple pneumoconiosis, the symptoms may be dueto chronic non-specific lung disease. In such cases,two independent diagnoses should be made.
Psychoneurosis is excluded only if there isno somatic effect. Thus psychogenic asthma isincluded if there is narrowing of the airways.
CLASSIFICATION OF CHRONIC NON-SPECIFICLUNG DISEASE
The purpose of proposing a classificationof the various forms of chronic non-specific lung disease is to clarify the presentconfusion in the clinical use of the terms chronicbronchitis, asthma, and emphysema. It is pro-posed that patients be classified according to thethree types of respiratory disorder commonlyassociated with these diagnostic labels:
1. Chronic or recurrent excessive secretion ofbronchial mucus.
2. Intermittent obstruction to bronchial air flow.3. Persistent obstruction to bronchial air flow.The following main subdivisions (which may
coexist) of chronic non-specific lung disease areproposed, and their correlation with currentterminology is outlined in Table I:
1. CHRONIC BRONCHITIS.-" Chronic bronchitisrefers to the condition of subjects with chronic orrecurrent excessive mucous secretion in thebronchial tree." The diagnostic criterion isclinical, and is chronic or recurrent cough withexpectoration which is not attributable toconditions excluded from chronic non-specificlung disease.
Infection of the bronchi is frequently but notnecessarily present.Not infrequently subjects who produce sputum
deny cough. Such subjects are included as havingbronchitis. Subjects who habitually swallowsputum should also be included as having chronicbronchitis.
Opinion is divided concerning the significanceof " dry" chronic bronchitis without hyper-secretion, which is excluded by the proposed
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+ + 0 Asthma Chronic bronchitisIntrinsic asthma with asthmaAsthmatic
bronchitis
+ 0 + Chronic Chronic bronchitisbronchitis with obstructive
Asthma lung disease (withEmphysema or without em-
physema)
O + + Asthma Partially reversibleEmphysema obstructive lung
disease (with orwithout emphy-sema)
+ + + Chronic Chronic bronchitisbronchitis with partially
Asthma reversible ob-Emphysema structive lung
disease (with orwithout emphy-sema)
I _ _ _ _ _ _ _
definition. Population surveys in Great Britainsuggest that a persistent cough without expectora-tion is uncommon.The words "chronic or recurrent" may be
defined as "occurring on most days for at leastthree months in the year during at least two years."
2. GENERALIZED OBSTRUCTIVE LUNG DISEASE.-"Generalized obstructive lung disease refersto the condition of subjects with widespreadnarrowing of the bronchial airways, at least onexpiration, causing an increase above the normalin resistance to air flow."There may be no clinical symptoms or signs
in the presence of demonstrable obstruction tobronchial air flow. Symptoms, when present,are abnormal breathlessness, which may beparoxysmal or persistent, and a sensation oftightness in the chest, often with wheezing. The
most characteristic signs are rhonchi of sibilantcharacter, but their presence or absence is notclosely related to the severity of the obstruction.
(i) Intermittent or Reversible Obstructive LungDisease: Asthma.-" Asthma refers to the con-dition of subjects with widespread narrowing of thebronchial airways, which changes its severity overshort periods of time either spontaneously orunder treatment, and is not due to cardiovasculardisease." The clinical characteristics are abnormalbreathlessness, which may be paroxysmal orpersistent, wheezing, and in most cases relief bybronchodilator drugs (including corticosteroids).
(ii) Irreversible or Persistent Obstructive' LungDisease.-Irreversible or persistent obstructivelung disease refers to the condition of subjectswith widespread narrowing of the bronchialairways, which has been present for more thanone year and which is unaffected by broncho-dilator drugs (including corticosteroids).
DEGREES OF SEVERITY OF GENERALIZEDOBSTRUCTIVE LUNG DISEASE
In subjects with generalized obstructive lungdisease:Lung impairment is present in those with
objective evidence of obstruction to air flow butwithout symptoms.Lung insufficiency is present in those with
persistent abnormal breathlessness.Lung failure is present in those whose arterial
carbon dioxide exceeds, or the arterial oxygen (inthe absence of a cardiac shunt) falls below, normallevels* when breathing air at normal atmosphericpressure. Lung failure may occur on exertionwithout failure at rest. The conditions underwhich failure occurs should be stated.Many subjects, if not the majority, with chronic
obstructive lung disease have some degree ofreversible and some irreversible obstruction. Thesubdivision suggested is, however, useful clinically.It is suggested that patients should be described ashaving reversible obstruction or asthma alone ifthey are symptom-free in remission or undertreatment.Many patients with irreversible chronic obstruc-
tive lung disease and with lung insufficiency orfailure are at present described as havingemphysema. Some such patients have little or noemphysema on post-mortem examination. It isappropriate to use the word emphysema as aclinical diagnosis only when combined clinical,radiological, and physiological evidence is such*Upper limit of normal for pC02 = 47 mm. Hg. Lower limit of
oxygen saturation=93% and of oxygen tension=75 mm. Hg.
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that the presence of anatomical emphysema can beconfidently asserted. Only in such cases shouldthe diagnosis be given as "chronic lunginsufficiency or failure with emphysema."At present no proposals are made for sub-
classification of the classes of chronic generalizednon-specific lung disease, for there is as yetinsufficient factual basis for such a classification.It is hoped that future systematic recording andcoding of observations upon these cases maypermit the development of a useful classification.Meanwhile the use of the main subdivisions invarious combinations will enable certain generallyrecognized types of case to be more accurately andintelligibly distinguished than is possible with thepresent confused terminology. All the possiblecombinations of the proposed subdivisions ofchronic non-specific lung disease are set out in theTable, where the diagnostic labels that are atpresent attached to them are compared with theterminology now proposed for each combination.
RECORDING OF CLINICAL AND RADIOLOGICALOBSERVATIONS
For purposes of comparative studies in differentcentres, it would be useful to have some uniformmethod of recording and coding clinical andradiological observations in patients with chronicnon-specific lung disease. A standard formfor recording certain items of clinical andradiological information in a standardized mannerwas drafted at the symposium. Clinicians whointend to make comparable studies may like to usethis form, duplicated copies of which can beobtained at a small charge from Dr. C. M.Fletcher, Postgraduate Medical School of London,Ducane Road, London, W.12.
THE USE OF LUNG FUNCTION TESTS INTHE STUDY OF CHRONIC NON-SPECIFIC
LUNG DISEASEDIVISIONS OF LUNG FUNCTION
Lung function can conveniently be consideredin terms of an air pump, an interface, and a bloodpump, or, in more conventional terms, ventilatoryfunction, alveolar-capillary function, andpulmonary circulatory function.
DISTURBANCES OF LUNG FUNCTION IN CHRONICNON-SPECIFIC LUNG DISEASE
In relation to the proposed clinical subdivisionsof chronic non-specific lung disease, it appears thatchronic bronchitis may be present withoutimpairment of lung function. The chiefimpairment in reversible obstructive lung disease
or asthma is increased resistance to air flow in thebronchial tree both on inspiration and expiration.
In subjects with irreversible obstructive lungdisease and with ventilatory insufficiency or failureany or all of the divisions of lung function may beimpaired, and a wide variety of patterns ofimpairment have been described. In cases withsevere emphysema there is usually a combinationof increased resistance to air flow in the bronchialtree (usually greater on expiration than on inspira-tion), increase of residual volume, unevenness ofventilation and perfusion, and impairment of gasexchange resulting, when severe, in hypoxia andhypercapnia, and an increase in static compliance.With this combination of disturbances anatomicalemphysema is usually thought to be present. Itsanatomical type, extent, and severity cannot bedetermined by function studies, for at present notenough is known about the correlation betweendifferent patterns of functional disturbance anddifferent pathological types of emphysema. It isnot proposed, therefore, to suggest any diagnosticcriteria or to put forward any system ofclassification based on disturbances of pulmonaryfunction.
In the course of time, if clinical, functional, andpathological observations are made by stan-dardized methods and recorded in a standardizedfashion, it may prove possible to suggestdiagnostic criteria for different forms of chronicnon-specific lung disease with and withoutdifferent kinds of emphysema.
MEASUREMENT OF IMPAIRED LUNG FUNCTION INCHRONIC NON-SPECIFIC LUNG DISEASE
All three aspects of lung function must beconsidered in any patient. There has been atendency to equate impairment of ventilatoryfunction with impairment of lung function,because this function is usually impaired early inthis group of diseases by obstruction to air flowand because its impairment is much easier tomeasure than impairment of function at the blood-gas interface or in the pulmonary circulation. Themore elaborate methods required to test theselatter functions are available in few centres. Forcorrelation with morbid anatomy and descriptionof functional syndromes, as complete an analysisas possible should be made in all cases. Aftercareful consideration of all techniques of lungfunction assessment known to the participants inthe conference, it was decided to recommend agroup of essential tests which must be done at anycentre concerned with advancing knowledge of thediagnosis and classification of chronic lung
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diseases, and then to give a supplementary list offunctions which should be tested out in the better-equipped centres and which are necessary for fullevaluation. The list is not an exhaustive one, andtests additional to those listed may providevaluable additional and confirmatory information.
A. ESSENTIAL TESTS.-The group of tests con-sidered to be essential comprises the following.
1. Ventilatory Function.-Single breath tests arerecommended, measuring the one-second forcedexpiratory volume (F.E.V.1.0) and vital capacity(F.V.C.) and also recording the ratio of the oneto the other. These tests should be done beforeand after inhalation of a bronchodilator aerosol.It is suggested that adrenaline and atropinecompound spray, 1 % isoprenaline or 0.25%phenylephrine hydrochloride, should be used. Itshould be administered for two minutes, using anebulizer whose effectiveness has been established.The Wright nebulizer (Aerosol Products(Colchester) Ltd., 87 Eccleston Square, London,S.W.1) has been found effective with a gas flow of10 1./min. The test should be repeated oneminute later.
2. Alveolar-capillary and Circulatory Function.-Some indication of impairment of thesefunctions can be derived from (a) measurementsof the ventilatory requirement on exercise, and(b) measurements at rest of arterial blood gasesand pH, in addition to assessment of disturbanceof the pulmonary circulation by clinical, radio-logical, and electrocardiographic studies.
(a) The type of exercise to be used will dependupon facilities. Its severity should be described.For estimation of the ventilatory cost of exertion,as opposed to a clinical estimate of exercisecapacity, a standardized work level should beemployed, using a step test, treadmill or bicycleergometer adjusted so that at least three minutesof exercise is possible. The exercise ventilationand ventilatory cost of the exercise should bemeasured. It is desirable to measure changes ino2 saturation during the exercise either by directestimation on arterial blood or by oximeter. Ifneither method is available, it must be notedwhether or not cyanosis develops or changes onexercise.
(b) Arterial blood gas and pH measurements atrest should be carried out with the subject breath-ing air and, if possible, when breathing 100%oxygen. Direct tension measurements of 02 andCO2 are greatly preferable. Alternative tech-niques are derivations of pCO2 from arterial CO2content and pH, or from mixed venous pCO2
estimated by rebreathing and estimation of oxygensaturation from Van Slyke analysis.
B. RECOMMENDED FUNCTION TESTS.-Thesupplementary list includes:
1. Subdivision of lung volume by open orclosed circuit methods or by body plethysmograph.
2. Forced inspiratory spirogram for comparisonwith expiratory spirogram.
3. Unevenness of ventilation, from singlebreaths using a nitrogen or helium meter or byserial washout using open or closed circuittechniques.
4. Distribution of pulmonary ventilation andperfusion by the full technique of Riley or one ofits simplified modifications or by expired gasanalysis.
5. Measurement of compliance, airways resis-tance, and work of breathing by oesophagealpressure with spirometer and pneumotachygraph,by airways interrupter or by body plethysmo-graph.
6. Apparent diffusing capacity for oxygen orcarbon monoxide, using either the steady state orthe single breath technique.
7. Ventilatory response to oxygen inhalation byspirometry.
RECORDING, GRADING, AND CODING OF RESULTSAbsolute values of the results of function tests
should be recorded. It would be convenient tocode them into slight, moderate, and severedeviations from normal. The degrees of distur-bance revealed by different tests could then betabulated in a simple fashion for correlation withpathological and clinical data similarly graded.When sufficient data on test results in normalindividuals of specified age, sex, and size havebeen accumulated, it may be useful to express theresults in particular patients as a percentage ofthe expected normal level. It is at presentpremature to propose any definite system ofexpressing or coding results. It is hoped that, solong as full anthropometric measurements anddetails of technique are provided, comparisonbetween results obtained by different methodsshould be useful.
REFERENCESGough, J., and Wentworth, J. E. (1949). J. roy. micr. Soc., 69, 231.Heard, B. E. (1958). Thorax, 13, 136.Scadding, J. G. (1959). Lancet, 1, 323.
APPENDIXLIST OF PARTICIPANTS
E. J. M. Campbell, M.D., M.R.C.P., Department of Medicine,Middlesex Hospital, London, W.l.
J. E. Cotes, M.R.C.P., Pneumoconiosis Research Unit of theMedical Research Cotncil, Llandough Hospital, nr. Penath,Glamorgan.
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horax: first published as 10.1136/thx.14.4.286 on 1 Decem
K. W. Donald, D.S.C., M.D., F.R.C.P., Department of Medicine,the University, Edinburgh.
C. M. Fletcher, C.B.E., M.D., F.R.C.P.,* Postgraduate MedicalSchool of London, Ducane Road, London, W.12.
J. C. Gilson, O.B.E., F.R.C.P.,* Pneumoconiosis Research Unitof the Medical Research Council, Llandough Hospital, nr. Penarth,Glamorgan.
J. Gough, M.D.,t Welsh National School of Medicine, Cardiff.Brian E. Heard, M.D., M.R.C.P., Postgraduate Medical School
of London, Ducane Road, London, W.12.A. G. Heppleston, M.D., M.R.C.P., Welsh National School of
Medicine, Cardiff.P. Hugh-Jones, M.D., F.R.C.P.,* Postgraduate Medical School
of London, Ducane Road, London, W.12.G. de J. Lee, M.D., M.R.C.P., Department of Medicine,
University of Oxford.J. G. Leopold, M.B., B.Ch., Welsh National School of Medicine,
Cardiff.C. B. McKerrow, M.D., M.R.C.P., Pneumoconiosis Research
Unit of the Medical Rescarch Council, Liandough Hospital, nr.
Penarth, Glamorgan.
R. S. McNeill, M.R.C.P., Department of Therapeutics andPharmacology, Queen's College, Dundee.
R. Marshall, M.D., M.R.C.P., Nuffield Department of Surgery,Radcliffe Infirmary, Oxford.D. D. Reid, M.D., Department of Medical Statistics, London
School of Hygiene and Tropical Medicine, Keppel Street, London,W.C.2.
L. McA. Reid, M.R.C.P., Institute of Diseases of the Chest,Brompton Hospital, London, S.W.3.
J. G. Scadding, M.D., F.R.C.P.,* Institute of Diseases of theChest, Brompton Hospital, London, S.W.3.G. Simon, M.D., M.R.C.P., X-ray Department, Brompton
