Susan Tarlo and Gary Liss, in their clear, concise review of the underrecognized problem of occupational asthma,1 suggest that peak expiratory flow rate (PEFR) be measured 4 times a day. We have found that obtaining 2-hourly measurements of PEFR and analyzing these data by means of a computer-assisted diagnostic aide (OASYS)2 is the best way of using serial peak flow readings in the diagnosis of occupational asthma.3,4 This technique, developed primarily by Sherwood Burge in the United Kingdom, reportedly has a sensitivity of 75% and a specificity of 94% in the diagnosis of occupational asthma.2 We find that the greater frequency of recording PEFR is helpful in identifying the relation of asthma to work, although it does entail considerable extra effort on the patient's part. However, if the purpose of the serial readings is explained, compliance is generally good.
Jeremy Beach Associate Professor and Residency Program Director Occupational Health Harold Hoffman Occupational and Environmental Medicine Specialist University of Alberta Edmonton, Alta.
Footnotes
Competing interests: None declared.
References
- 1.Tarlo SM, Liss GM. Occupational asthma: an approach to diagnosis and management. CMAJ 2003; 168(7):867-71. [PMC free article] [PubMed]
- 2.Oasys Research Group. Oasys and occupational asthma [Internet]. UK: Midlands Thoracic Society; [no date]. Available: www.occupationalasthma.com (accessed 2003 June 26).
- 3.Burge PS, Pantin CF, Newton DT, Gannon PF, Bright P, Belcher J, et al. Development of an expert system for the interpretation of serial peak expiratory flow measurements in the diagnosis of occupational asthma. Midlands Thoracic Society Research Group. Occup Environ Med 1999; 56: 758-64. [DOI] [PMC free article] [PubMed]
- 4.Baldwin DR, Gannon P, Bright P, Newton DT, Robertson A, Venables K, et al. Interpretation of occupational peak flow records: level of agreement between expert clinicians and Oasys-2. Thorax 2002;57:860-4. [DOI] [PMC free article] [PubMed]