ABSTRACr From a continuous series of 886 postmortem examinations on coal mine workers in New South Wales, Australia, from 1949 to 1982 and their histories the following data were obtained: age at death (886 cases), percentage of emphysema in both lungs (Heard method) (870 cases), bronchial gland wall (G-W) ratio (Reid Index) (412 cases), chest radiograph within 10 years of death (792 cases), history of work at the coal face (844 cases), history of amount of tobacco smoked (606 cases), and FEV, five years before death (278 cases). Linear regression analysis showed the following: (1) The severity of emphysema had a significant positive regression on years of face work independently of age at death. (2) The severity of emphysema had a significant positive regression on the severity of x-ray pneumoconiosis, which was best defined in the non-smoking group and the non-bronchitic group. (3) There was a significant multiple linear regression relationship between severity of emphysema (dependent variable) and pneumoconiosis and G-W (independent variables). The ratio of standardised regression coefficients was pneumoconiosis: G-W = 3:1. (4) The severity of x-ray pneumoconiosis had a significant positive regression on years of face work and a negative regression on smoking amount. (5) G-W ratio had significant positive regressions on age of death and severity of emphysema but not years of face work or severity of pneumoconiosis. (6) Smoking was not correlated with severity of emphysema or G-W ratio. (7) FEV, (% predicted) was significantly negatively correlated with bronchitis, emphysema, and pneumoconiosis. (8) Severity of pneumoconiosis and emphysema have declined slightly but significantly over the 33 year period, but there has been no significant change in G-W ratio during 1960-82.The analyses of postmortem data obtained from the lungs of 186 coal workers and associated clinical and physiological data from the same workers have allowed several conclusions to be drawn about pneumoconiosis, emphysema, and bronchitis in the coal industry.' The main conclusions were:(1) There is a quantitative relationship between the severity of emphysema postmortem and the postmortem severity of pneumoconiosis or x-ray pneumoconiosis in radiographs taken less than five years before death.(2) Both postmortem emphysema and postmortem pneumoconiosis are quantitatively related to

From the Joint Coal Board, Sydney, A ustralia From bronchial measurements in 136 deceased coal miners a comparison with well-documented ante-mortem findings shows that with increasing clinical severity of chronic bronchitis there is increasing narrowing of intrapulmonary airways due to wall thickening at the expense of the lumen. With the aid of the Reid index (gland/wall ratio) and a new proposed index which more directly measures airway obstruction-the wall internal to cartilage/lumen radius ratio-both of which tend to be independent of bronchus size but change with increasing abnormality-it is possible to quantitate chronic bronchitis pathologically and to obtain satisfactory correlations with ante-mortem data. Chronic bronchitis may thereby be evaluated independently from pneumoconiosis and emphysema, thus facilitating the study of their separate relationships with cigarette smoking and with other possible aetiological factors.As part of a long-term study of respiratory diseases in post-mortem lung specimens from coal miners we recently began measuring bronchi and calculating ratios including the Reid index (1960).The purpose of this paper is to present some of our findings, covering so far some 136 individual miners. Our objectives have been, first, to try to devise a system of severity grading of chronic bronchitis post mortem which could be satisfactorily related to the ante-mortem status; secondly, using such a system, to study the relationships of the post-mortem pathology to such ante-mortem factors as cigarette smoking and occupation, and possibly other constitutional or environmental influences. This paper covers only the first objective. Several methods have been described for quantitating chronic bronchitis, mostly in relation to the degree of hypersecretion or mucous gland or goblet cell hyperplasia noted. The pathological signs of infection are not readily quantitated. Our own interest is mainly concerned with the obstructive phase of this disease, and with those measurable aspects of the pathology which appear to be relevant to this phase.After examining a number of Gough sections from the lungs of miners affected by severe chronic bronchitis our interest in wall/lumen measurements was aroused by the gross wall thickening and lumen narrowing seen macroscopically, extending through most of the visible intrapulmonary tree. An attempt to quantitate this change was undertaken.

In a series of 89 subjects (all coal miners or ex-coal miners) a high order of correlation has been found between diaphragmatic excursus measured within five years of death and the necropsy assessment of emphysema in the lungs. In the absence of other common factors that reduce the range of movement of the diaphragm, measurements of diaphragmatic excursus provide a statistical prediction of the severity of emphysema. The individual variance, however, is such that this assessment should be used only as part of a range of clinicoradiological, physiological, and electrocardiographic indicators of emphysema severity.Evidence is presented to show that the movement of the diaphragm is restricted in the predominantly emphysematous members of the series but approaches full normal range in the group with predominant chronic obstructive bronchitis.The appearance of rarefied lung markings, a low flat diaphragm, a small low central heart shadow in a roomy thorax, and enlargement of the retrosternal clear space have been used as radiological diagnostic signs of emphysema for many years past. Simon (1956, 1964) also drew attention to the diminished range of diaphragm movement, which he stated was often less than 1 in (2'5 cm) in severe emphysema. He gave the normal range as 2 to 4 in (5 to 10 cm). Reid (1960) and Reid and Millard (1964) have clarified the relationship of the radiographic and pathological features of emphysema. Milne and Bass (1969) found a good correlation between the specific dynamic pulmonary compliance and diaphragmatic excursus.For the present paper the range of diaphragmatic movement in coal miners as recorded from measurement on fluoroscopic screening has been compared with the amount of emphysema found at necropsy in the lungs of the same subjects. From this a prediction formula for antemortem quantitation of emphysema has been derived. In a proportion of the subjects the availability of fullsize chest radiographs taken in full inspiration and full expiration enabled a parallel measurement to be made with the films overlain with first thoracic vertebrae exactly superimposed; these results were compared with those from fluoroscopy. DEFINITIONS AND METHODSThere were 89 subjects (from a larger necropsy series) for whom both diaphragmatic excursus, measured within five years of death, together with other required data and necropsy assessment of emphysema were on record.The subjects were either retired coal miners or employed coal miners exhibiting a wide range of radiological severity of coal dust pneumoconiosis and at necropsy a corresponding range pathologically. All had some degree of emphysema pathologically though in 12 subjects it was minimal. Fifty-three (60%) were regarded at necropsy as having emphysema of varying degrees of the Gough 'dust focal' type. In many of these and also in the remaining 36, other types of emphysema-centrilobular, panacinar, and bullouswere also present. In many instances, chronic bronchitis, simple or obstructive, was adjudged to be present both clinically and pathologic...

No abstract

No abstract