Respiratory Function during the Day in Rayon Workers—a Study in Byssinosis

THE CLINICAL STUDY by Tiller in this issue indicates that card and blow-room workers in a mill spinning only rayon did not have byssinosis and that those workers who had had byssinosis while working in cotton spinning mills ceased to have the characteristic chest tightness on Mondays when they worked in the rayon mill. A significant lowering of ventilatory capacity during a Monday has recently been demonstrated in card-room workers in cotton spinning mills (McKerrow, McDermott, Gilson and Schilling, 1958.) There were two reasons for believing that this was a specific reaction to the dust. The same workers showed no significant lowering of ventilatory capacity when employed outside the cardroom and coal miners exposed to comparable quantities of coal dust showed no reduction in ventilatory capacity on a Monday. Therefore, it was decided to make a similar study of rayon workers. If they had no significant physiological change it would confirm the results of the clinical study. Method Ventilatory capacity was estimated from the volume of air expired in 0-75 second during a forced expiration. This volume was multiplied by 40 to give the indirect maximum breathing capacity. The apparatus used was similar to that described by Gaensler (1951). Five readings were taken and the results calculated from the mean of the three highest (correct to B.T.P.S.). Procedure Eight men and five women who had had byssinosis while working in raw cotton mills were available for the test. They were matched as far as possible for age and job with workers in the same factory who had never had symptoms of byssinosis (Table /). One set of five readings of forced expiratory volume was taken for each worker on a Monday at 7.30 a.m. before going into the workrooms. The second set was taken after 4.15 p.m. on the same day. Table I