Facilities for investigating occupational asthma in UK non-specialist respiratory departments.

BACKGROUND: The facilities which should be available to physicians offering specialist occupational asthma services have recently been agreed upon by a UK panel of experts. AIMS: This study aimed to investigate whether these facilities are available in UK non-specialist secondary care respiratory departments and to document tertiary care referral patterns. METHODS: A random sample of 100 UK respiratory units was selected, and the lead consultant invited to participate. Face-to-face interviews were conducted to document information on departmental facilities available for investigating cases of occupational asthma and utilization of tertiary referral centres. RESULTS: In total, 66% of consultants interviewed had seen a case of occupational asthma in the previous month, and 76% reported having ever referred a patient with suspected occupational asthma to a specialist centre for further investigation (referral distance range 1-111 miles). All the departments were able to perform the investigations previously deemed an absolute necessity in all patients. The availability of in-house facilities that were deemed as must be available varied between 3-100%. CONCLUSIONS: The results of this study demonstrate that while the majority of basic facilities are widely available, many respiratory departments do not have direct access to investigations routinely required to investigate occupational asthma. Access to specialist occupational respiratory centres varies within the UK, and in some parts of the country involves long travelling distances for patients.

Are we failing workers with symptoms suggestive of occupational asthma?

AIMS: To assess the route to secondary care for patients with possible occupational asthma, and to document the duration of workrelated symptoms and referral times. METHODS: Consecutive patients with suspected occupational asthma were recruited to a case series from six secondary care clinics with an interest in occupational asthma. Semi-structured interviews were performed and hospital case notes were reviewed to summarise relevant investigations and diagnosis. RESULTS: 97 patients were recruited, with a mean age of 44.2 years (range 24-64), 51 of whom (53%) had occupational asthma confirmed as a diagnosis. Most (96%) had consulted their general practitioner (GP) at least once with work-related respiratory symptoms, although these had been present for a mean of 44.6 months (range 0-320 months) on presentation to secondary care. Patients experienced a mean delay for assessment in secondary care of 4 years (range 1-27 years) following presentation in primary care. CONCLUSIONS: Significant diagnostic delay currently occurs for patients with occupational asthma in the UK.

Occupational asthma: an assessment of diagnostic agreement between physicians.

OBJECTIVES: To investigate the levels of agreement between expert respiratory physicians when making a diagnosis of occupational asthma. METHODS: 19 cases of possible occupational asthma were identified as part of a larger national observational cohort. A case summary for each case was then circulated to 12 physicians, asking for a percentage likelihood, from the supplied information, that this case represented occupational asthma. The resulting probabilities were then compared between physicians using Spearman's rank correlation and Cohen's kappa coefficients. RESULTS: Agreement between the 12 physicians for all 19 cases was generally good as assessed by Spearman's rank correlation. For all 66 physician-physician interactions, 45 were found to correlate significantly at the 5% level. The agreement assessed by kappa analysis was more variable, with a median kappa value of 0.26, (range -0.2 to +0.76), although 7 of the physicians agreed significantly (p<0.05) with >or=5 of their colleagues. Only in one case did the responses for probability of occupational asthma all exceed the "on balance" 50% threshold, although 12 of the 19 cases had an interquartile range of probabilities not including 50%, implying "on balance" agreement. The median probability values for each physician (all assessing the identical 19 cases) varied from 20% to 70%. Factors associated with a high probability rating were the presence of a positive serial peak expiratory flow Occupation Asthma SYStem (OASYS)-2 chart, and both the presence of bronchial hyper-reactivity and significant change in reactivity between periods of work and rest. CONCLUSIONS: Despite the importance of the diagnosis of occupational asthma and reasonable physician agreement, certain variations in diagnostic assessment were seen between UK expert centres when assessing paper cases of possible occupational asthma. Although this may in part reflect the absence of a normal clinical consultation, a more unified national approach to these patients is required.

Reproducibility and validity of a Yan-style portable citric acid cough challenge.

Although many different methods of measuring cough reflex sensitivity have been published, few are simple enough to use outside of a hospital or laboratory environment. The aim of this study was to develop a simple, quick, and portable cough challenge, assess its reproducibility, and compare its results with those measured by an existing established hospital protocol. Twenty-five volunteers performed cough challenges based on an established hospital dosimeter protocol, and, on a separate occasion, by a protocol inhaling citric acid from DeVilbiss 40 hand-held nebulisers (citric acid concentrations of 10-3000 mM). Reproducibility of the hand-held cough challenge was assessed in 11 volunteers. Cough thresholds were consistently higher by the hand-held method than by the hospital dosimeter method. The geometric mean citric acid concentrations causing two coughs (threshold D2) were 3.14 and 2.77 log mM, respectively (p<0.001). The geometric mean (95% CI) difference between the tests was 0.51 log mM (0.18-0.83) of the average of the two values. Cough D2 thresholds attained by the two techniques did, however, show significant correlation (r=0.95, p<0.0001). The coefficient of repeatability for the hand-held method was 0.40 log mM. Administering citric acid from DeVilbiss 40 hand-held nebulisers offers a rapid, portable, and reproducible cough challenge in healthy volunteers. The results correlate well with an existing Mefar dosimeter challenge, but give two to three times greater cough thresholds.

Immunologic response to inhaled endotoxin: changes in peripheral cell surface markers in normal individuals.

Monocyte cell surface CD14 increases following both in vitro challenge with lipopolysaccharide (LPS) and exposure to organic dusts. We investigated 9 volunteers, mean age 39 years (range, 29-53 years). Each inhaled increasing concentrations of lipopolysaccharide (0.5 microg, 5.0 microg, and 20 microg). Monocyte cell surface CD14 (expressed as mean linear fluorescence) was measured before and after using flow cytometry. Upregulation of CD14 (up to 6 hours after LPS exposure) did not differ significantly between LPS (mean, 35.8; standard deviation [SD]; 54.3), n = 7 after 20 l g LPS) in comparison to placebo (39.3 [49.0]; n = 7). Maximum mean (SD) percentage CD14 upregulation up to 6 hours after challenge differed, but not significantly between those experiencing a clinically significant event (58.4 [49.2]) in comparison to those who did not (13.8, [43.2]; P = 0.27). Two individuals with a marked clinical response developed marked CD14 upregulation after exposure to LPS.