Pilot study of closing volume in byssinosis.
Fairman-RP; Hankinson-J; Imbus-H; Lapp-NL; Morgan-WK
Br J Ind Med 1975 Aug; 32(3):235-238
A study of the relative sensitivities of forced expiratory volume in one second, maximal mid-expiratory flow, and closing volume in the detection of subjects with byssinosis was carried out in a North Carolina cotton mill. Altogether 35 workers participated in the study. Of these, nine showed a decline in 10 percent or more during the first work shift that followed the weekend break. Twelve subjects showed a decrease in midexpiratory flow of 15 percent or more. In contrast only six workers exhibited a 10 percent increase in closing capacity, while ten showed a 10 percent increase in closing volume. Recent evidence of the magnitude of variability in closing volume maneuvers suggests that our chosen level of change was too low. A 40 percent change closing volume would have identified only five subjects. Closing volume is a more complex maneuver for the subject being tested and for the technician to perform, is more time consuming, and is subject to greater variation. To have any advantage over spirometry, closing volume would have to be appreciably more sensitive. The present findings study suggest that it is not. However, the midexpiratory flow may prove to be more sensitive than the forced expiratory volume in the detection of byssinosis.
NIOSH-Author; Respiratory-function-tests; Respiratory-system-disorders; Diagnostic-tests; Cotton-industry; Textile-workers; Occupational-diseases; Test-methods
British Journal of Industrial Medicine