With the aid of provocative challenges with hay in patients suffering from
farmer's lung, a comparison of the protective effectiveness of the Airstream Helmet (main filter P2) and of the Sundström Mask (main filter P3) was undertaken. A total of 42 farmers were admitted to the study. In 14, as indicated by an expertise, a workplace-related provocative challenge by the farmers' own hay was carried out and was shown to be positive with respect to the presence of
farmer's lung disease. In 28 farmers in whom an inhalative provocative challenge with hay had been demonstrated to be positive, inhalative provocative challenges were again performed using the farmers' own hay while the farmers were wearing protective respirators--14 with the Airstream Helmet, (main filter P2) and 14 with the Sundström Mask (main filter P3). When the
respirator was not worn, a statistically significant increase in the number of leukocytes and temperature vis-a-vis the baseline values was observed. Partial
oxygen pressure, vital capacity, total lung capacity and DCO, all showed a statistically significant decrease as compared with the baseline figures. The provocative challenges performed while the subjects were wearing the
respirators also revealed a statistically significant increase in the number of leukocytes and in temperature, which, however, was statistically significantly smaller than that induced by provocation without the
respirator. A similar pattern of behaviour was also found in the decrease in vital capacity,
oxygen partial pressure, total lung capacity and DCO. No statistically significant differences were observed between the provocation figures obtained with the Airstream Helmet as compared with those obtained with the Sundström Mask.(ABSTRACT TRUNCATED AT 250 WORDS)