LUNG CINESCINTIGRAPHY IN THE DYNAMIC ASSESSMENT OF VENTILATION AND MUCOCILIARY CLEARANCE OF ASBESTOS-CEMENT WORKERS

Objectives-To verify in vivo whether lung cinescintigraphy confirms th e effect of asbestos on the patency of the smallest airways and on the efficiency of mucociliary clearance in asbestos cement workers. Metho ds-39 male subjects were examined: 30 asbestos cement workers and nine workers never exposed to occupational respiratory irritants. All subj ects had a chest radiograph (International Labour Organisation (ILO) 1 980); standard questionnaire on chronic bronchitis; spirometry; arteri al blood gas analysis; carbon monoxide transfer factor (TLco(sb)); pul monary o(2) and co(2) ductances (Duo(2), Duco(2)); electrocardiogram; and lung cinescintigraphy after radioaerosol inhalation for the measur ement of mucociliary clearance time in vivo in the smallest ciliated a irways and for the assessment of radioaerosol deposition in alveoli (a lveolar deposition index). Results-Apart from nine non-exposed subject s, the 30 asbestos cement workers were so classified on the basis of c hest radiography: nine of them as healthy exposed, 10 with pleural pla ques, and 11 with asbestosis. The four groups had similar ages, work s eniority, and smoking habits. Exercise dyspnoea was significantly more frequent in asbestos cement workers. Lung function variables of worke rs with effects related to asbestos were significantly lower than the other two groups. The Pao(2), TLco(sb) and Duo(2) mean values were sig nificantly lower in exposed workers than non-exposed. The mean Paco(2) value was significantly higher in the asbestosis group than in the ot her three groups. Workers with effects related to asbestos showed a si gnificantly lower alveolar deposition index and a significantly higher mucociliary clearance time than the other two groups, Subjects with a sbestosis showed similar differences from those with pleural plaques. Conclusions-Lung cinescintigraphy confirms in vivo the effects of asbe stos on bronchiolar and alveolar patency and on efficiency of mucocili ary clearance in the smallest ciliated airways. Finally, lung cinescin tigraphic variables are able to discriminate workers with asbestosis f rom those with pleural plaques.