Postmortem evaluation of the use of diaphragmatic excursus in assessment of pulmonary emphysema in coal miners

Abstract

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...

The cross sectional area of diaphragmatic muscle fibres in emphysema, measured by an automated image analysis system

“…Steele and Heard did not find an increase in the thickness or volume of diaphragmatic muscle, assessed macroscopically, in patients with chronic bronchitis. The apparent discrepancy between this and the present study may be due to the fact that diaphragmatic movement has been shown to be related to emphysema, but not to chronic bronchitis (McKenzie, Outhred and Glick, 1972). The diaphragm undergoes hypertrophy when forced to work hard over a long period of time (Comroe, 1974) and thus although the diaphragmatic excursion has been shown to be reduced in chronic airways obstruction (Simon 1964;Milne and Bass 1969) and in fact inversely related to the extent of emphysema at autopsy (McKenzie et a!.)…”