Occupational Asthma Reference
Burge PS, Pantin CFA, Newton DT, Gannon PFG, Bright P, Belcher J, McCoach J, Baldwin DR, Burge CBSG and the Midlands Thoracic Society Research Group,
Development of an expert system for the interpretation of serial peak expiratory flow measurements in the diagnosis of occupational asthma,
Occup Environ Med,
Keywords: Birmingham, oa, oasys, PEF, standard, occupational asthma, peak flow, methods, hospital, UK, asthma, exposure, causes, FEV1, non-occupational, challenge, sensitivity, specificity
If asthma is due to work exposures there must be a relationship between these exposures and the asthma. Asthma causes airflow obstruction which can be measured with portable meters, which usually measure peak expiratory flow, or sometimes FEV1, which can be measured serially (for instance two-hourly) over several weeks at and away from work. Once occupational asthma develops, the asthma will be induced by many non-specific triggers common to non-occupational asthma. The challenge is to identify changes in peak expiratory flow due to work amongst other non-occupational causes. Standard statistical tests have been found insensitive or non-specific, principally because of the variable period for deterioration to occur following exposure, and the sometimes prolonged time for recovery to occur, such that days away from work may initially have lower measurements than days at work. We have developed a computer assisted diagnostic aid (Oasys), to separate occupational from non-occupational causes of airflow obstruction. Oasys-2 is based on a discriminant analysis, and achieved a sensitivity of 75% and a specificity of at least 94%. A neural network version in development has improved on this. Both have been based on expert interpretation of peak flow measurements plotted as daily maximum, mean and minimum, with the first reading at work taken as the first reading of the "day". Oasys has been evaluated against measurements made in a wide range of occupational situations using independent criteria. Oasys is sufficiently developed to be the initial method for the confirmation or exclusion of occupational asthma.
There are no associations for this paper.
Please Log In or Register to put forward this reference as evidence to a question.
Please sign in or register to add your thoughts.