1 Using Control Chart Method to Monitor Occupational Asthma
نویسنده
چکیده
ABSTRACT The purpose of this research was to investigate whether the Shewhart control chart method can be used as an effective method to detect and monitor occupational asthma. Peak expiratory flow (PEF), a lung function marker, from 45 workers was used for this study. Control charts of PEF measurements at work and away from work were constructed. Multiple rules were developed and investigated. Reviewing the results, the best rule showed a sensitivity of 85.71%, specificity of 87.50%, and an error rate of 13.33% in detecting occupational asthma. Excluding the dubious cases, the test produced a sensitivity of 95.24%, a specificity of 95.83% and an error rate of 4.44%. Also, control chart method was used to detect lung function deterioration at work. The Average and Range control chart provided a method to monitor the acute and chronic conditions of asthma and characterize the PEF variability. The magnitude of variation was estimated using Variability Index. The results of this investigation were as good as and in some cases better than published clinical guidelines. This research showed that the control chart method is an effective, simple and inexpensive tool for early intervention in workers suspected for occupational asthma.
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