Abstract

Miller, G. J., Hearn, C. E. D., and Edwards, R. H. T. (1971).Brit. J. industr. Med.,28, 152-158. Pulmonary function at rest and during exercise following bagassosis. Lung function and exercise responses were investigated in two groups of Indian bagasse workers to assess whether there were any permanent sequelae following regular exposure to bagasse dust in a group of 12 men who had developed bagassosis and a group of six who had not. Ventilatory capacity, lung volumes, single breath carbon monoxide transfer factor (TF), diffusion capacity of the alveolar-capillary membrane (Dm), and volume of blood in the pulmonary capillaries (Vc) were measured, and then exercise responses were investigated with a cycle ergometer. The ventilatory response to hypercapnia was assessed by a modified re-breathing method.

The group of 12 patients had small but significant reductions in lung volumes, TF, and Dm 7 to 10 years after the acute episode. The ventilatory responses to exercise and hypercapnia were increased but exercise capacity was normal and limited by the cardiovascular responses. Exercise hyperventilation was the likely explanation for the exertional dyspnoea in this group.

Six of a group of workers who had been regularly exposed to mouldy bagasse dust without developing bagassosis and had a significant reduction in ventilatory capacity during exposure were found to have normal lung function and exercise responses two years after withdrawal from bagasse.

Immunological reactivity to an extract of Thermoactinomycetes vulgaris was found to have subsided after withdrawal from bagasse dust, although it can persist for six years. In a single case, disodium cromoglycate failed to suppress the late systemic reaction provoked by the inhalation test.