Occupational Asthma Reference

Cote J, Kennedy S, ChanYeung M, Quantitative Versus Qualitative Analysis Of Peak Expiratory Flow In Occupational Asthma, Thorax, 1993;48:48-51,

Keywords:

Known Authors

Moira Chan-Yeung, University of Hong Kong Moira Chan-Yeung

Susan Kennedy, Vancouver Susan Kennedy

If you would like to become a known author and have your picture displayed along with your papers then please get in touch from the contact page. Known authors can choose to receive emails when their papers receive comments.

Abstract

BACKGROUND
Peak expiratory flow rates (PEF) are often used to confirm the diagnosis of occupational asthma. The records are usually analysed qualitatively, and this may lead to interobserver disagreement. In this study the diagnostic value of a qualitative assessment of change in PEF was compared with objective measures of change in PEF and the results of a specific inhalation challenge test with plicatic acid.

METHODS
Twenty five patients with possible red cedar asthma recorded PEF six times a day for three weeks at work and for two weeks away from work and underwent a challenge test with plicatic acid at the end of the recording period. Patients were considered to have cedar asthma if the FEV1 after inhalation of plicatic acid was 15% or more below that on the control day. PEF was plotted against time and assessed qualitatively by three physicians. The graph was considered positive for cedar asthma if two of the three physicians agreed that PEF was lower at work than away from work. The 95% confidence interval for variation in PEF between periods at work and away from work was also obtained from 15 asthmatic patients without occupational asthma. Differences in PEF between periods at work and away from work were considered positive for occupational asthma in the patients exposed to cedar when they were outside the 95% confidence interval for variations in PEF in the 15 patients whose asthma was nonoccupational.

RESULTS
Of the 25 men studied, 15 had a positive response to plicatic acid. The qualitative PEF analysis had a sensitivity of 87% and a specificity of 90% in confirming red cedar asthma as diagnosed by the specific challenge test. Among the objective methods tested, only the difference in mean PEF between the maximum PEF at weekends and the minimum PEF on working days had a sensitivity (93%) greater than that of the qualitative method and a similar specificity.

CONCLUSIONS
The qualitative assessment of PEF is a good diagnostic test for cedar asthma. Only one objective method of PEF analysis proved to be slightly more sensitive than the qualitative method and similar in specificity.

Full Text

Full text of this reference not available

Please Log In or Register to add the full text to this reference

Associated Questions

There are no associations for this paper.

Please Log In or Register to put forward this reference as evidence to a question.

Bohrf Occupational Asthma Guidelines

This reference has been analysed as part of the BOHRF occupational asthma guidelines. Please click to view the Bohrf occupational asthma guideline data for this reference.

Comments

Please sign in or register to add your thoughts.


Oasys and occupational asthma smoke logo