Background -Serial peak expiratory flow (PEF) measurement is usually the most appropriate first step in the confirmation ofoccupational asthma. Visual assessment of the plotted record is more sensitive and specific than statistical methods so far reported. The use ofvisual analysis is limited by lack of widespread expertise in the methods. A computer assisted diagnostic aid (OASYS-2) has been developed which is based on a scoring system developed from visual analysis. This removes the requirement for an experienced interpreter and should lead to the more widespread use of the technique. Methods -PEF records were collected from workers attending an occupational lung disease clinic for investigation of suspected occupational asthma and from workers participating in a study of respiratory symptoms in a postal sorting office. PEF records were divided into two development sets and two gold standard sets. The latter consisted of records from workers in which a final diagnosis had been reached by a method other than PEF recording. An experienced observer scored individual work and rest periods for the two development set PEF records; linear discriminant analysis was used to compare measurements taken from development set 1 records with visual scores. Two equations were produced which allowed prediction of scores for individual work or rest periods. The development set 2 was used to determine how these scores should be used to produce a whole record score. The first gold standard set was used to determine the whole record score which best separated those with and without occupational asthma. The second set determined the sensitivity and specificity of the chosen score. Results -Two hundred and sixty eight PEF records were collected from 169 workers and divided into two development sets (81 and 60 records) and two gold standard sets (60 and 67 records). Linear discriminant analysis produced equations predicting the score for work periods incorporating five indices of PEF change and one for rest periods using seven indices. These equations correctly predicted the score for development set 1 work and rest periods on 61% of occasions (K=0.47). The whole record score for development set 2 records, after weighting for definite or definitely no occupational effect, correlated with the visual score (correlation coefficient 0.86).Comparison with gold standard set 1 identified a cut off which proved to have a sensitivity of 75% and a specificity of 94% for an independent diagnosis of occupational asthma when applied to gold standard set 2. Conclusions -These results suggest that the sensitivity and specificity of analysing PEF records for occupational asthma using OASYS-2 approaches that of visual analysis, but it should be absolutely reproducible. The performance of OASYS-2 is more specific and approaches the sensitivity of other statistical methods of analysis. The evaluation ofa large number of PEF records from workers exposed to different sensitising agents suggests that these results should be robust and should be re...

Regional pulmonary glucose metabolism (MRglu; mumol h-1 g-1), extravascular lung density (D(EV); g cm-3) and vascular volume (VB; ml cm-3) were measured in a single midthoracic transaxial slice (approximately 2 cm thick) using position emission tomography (PET) in seven patients with histologically proven sarcoidosis. The measurements were repeated 1-7 months later after steroid therapy (in two cases, no treatment) in order to assess MRglu as an index of inflammation and relate it to routine pulmonary function tests, chest radiography and serum angiotensin converting enzyme (SACE) levels. MRglu was computed from serial lung scans and peripheral venous blood samples for 60 min following an i.v. injection of 18F-2-fluoro-2-deoxy-D-glucose (18FDG). Both MRglu (which was increased in six of seven patients) and elevated SACE levels returned to normal in those patients treated with high-dose steroids. Regional vascular volume was normal in six of seven cases and did not change significantly with therapy. The high tissue density measured in all patients decreased significantly in two of three patients treated with 40 mg prednisolone daily. The abnormal MRglu observed in active sarcoidosis becomes normal pari passu with SACE levels during high-dose steroid therapy. We conclude that MRglu measured with 18FDG and PET may reflect "disease activity" in sarcoidosis in quantitative terms (per gram lung tissue) and in respect of disease distribution.

Objective-To investigate the ratio of inhaled corticosteroid to bronchodilator as a measure of the quality of asthma prescribing by general practitioners.Design-Ecological cross sectional study linking general practitioner asthma prescribing with hospital admission data and a measure of deprivation.Subjects-11 family health services authorities in the West Midlands region and 99 general practices in North Staffordshire.Main outcome measures-Hospital admission rates for asthma; the ratio of inhaled corticosteroid to bronchodilator; and Townsend deprivation scores.Results-No overall significant correlation was found between admission rates for asthma and corticosteroid:bronchodilator ratios for family health services authorities (Spearman's rs = -0.109, P = 0.750) or general practices (rs = -0.084, P = 0.407). In deprived family health services authority areas and general practices an inverse non-significant correlation existed between admission rates for asthma and corticosteroid:bronchodilator ratios (rs = -0.300, P = 0.624; rs = -0.218, P = 0.136). In contrast, in more affluent areas and general practices a positive non-significant correlation existed between admission rates and corticosteroid:bronchodilator ratios (rs = 0.371, P = 0.468; rs = 0.038, P = 0.792).Conclusion-Although the corticosteroid:bronchodilator ratio may be a valid indicator of the quality of prescribing for individual patients with asthma, caution should be applied in interpreting aggregated ratios. Differences in the severity of asthma or the prevalence of chronic obstructive pulmonary disease may explain inconsistent associations between admission rates for asthma and corticosteroid:bronchodilator ratios in family health services authorities and general practices with different deprivation scores. IntroductionThe ratio of inhaled corticosteroid to bronchodilator is a potential indicator of the quality of prescribing for asthma at aggregated family health services authority and general practice level.' A higher ratio reflects greater prescribing of inhaled corticosteroids relative to bronchodilators, a feature regarded as good practice.2 Nevertheless, few studies have validated the corticosteroid:bronchodilator ratio as an indicator of good quality prescribing because of the paucity of asthma outcome measures. At aggregated level, hospital admission rates for asthma are the only available outcome measure of asthma morbidity.At practice level two recent studies in the United Kingdom have found an association between hospital admission rates for asthma and corticosteroid:bronchodilator ratios.3 4 Both showed that practices with

Background-A previous retrospective study suggested that a policy of regular anti-pseudomonal antibiotic treatment improved pulmonary function and increased survival in patients with cystic fibrosis chronically infected with Pseudomonas species. The results of a prospective multicentre study to compare the eVects on pulmonary function and mortality of three monthly elective anti-pseudomonal antibiotic treatment with conventional symptomatic treatment are reported. Methods-Sixty patients with cystic fibrosis, chronically infected with P aeruginosa, were randomised to the two treatment arms (elective or symptomatic) and followed clinically at yearly reviews. The major end points were changes in forced expiratory volume in one second (FEV 1 ) and forced vital capacity (FVC). Survival was a secondary end point. Results-Patients in the symptomatic group received a mean of three antibiotic treatments each year and those in the elective group received four antibiotic treatments during each year of the study. No significant diVerences in FEV 1 and FVC were found between the two groups after three years. There was a statistically non-significant higher rate of deaths in the elective group (n = 4), three of which were associated with B cepacia infection, compared with the symptomatic group (n = 0). Conclusions-This study did not demonstrate an advantage of a policy of elective antibiotic treatment over symptomatic treatment in patients with cystic fibrosis chronically infected with Pseudomonas species. (Thorax 2000;55:355-358)

Cryptogenic fibrosing alveolitis (CFA) is characterized by interstitial fibrosis and parenchymal inflammation. Eleven patients with CFA (10 proved by lung biopsy) were followed over 2 yr using clinical symptoms, radiographic change, and pulmonary function tests to adjust their treatment. Lung lavage, positron camera (PET) measurements of regional extravascular lung density (Dev), pulmonary blood volume (Vb), and the metabolic rate for 18F-deoxyglucose (MRglc), clearance of 99mTc-diethylenetriaminepentacetate (99mTc-DTPA) aerosol, and lung uptake of 67Ga were measured initially and at the end of the first year to give a profile of the inflammatory response. Compared with normal subjects, there was an increased percentage of neutrophils and eosinophils in the lung lavage, increased Dev (p less than 0.002) with no significant difference in Vb, increased MRglc (p less than 0.02), 99mTc-DTPA clearance (p less than 0.002), and 67Ga uptake (p less than 0.02). The smallest increases in Dev were seen in the two patients with most destruction shown by lung biopsy. There were inverse correlations between Dev and both FVC and TLC, but a direct correlation between Vb and transfer factor. 99mTc-DTPA clearance changed concordantly with clinical status and radiographic and respiratory function changes during the first year. If glucose utilization (MRglc) remained in the normal range between the initial and first yearly assessment, the patient improved or remained stable during the second year as shown by clinical status and radiographic and respiratory function measurements. If it rose or remained high, the patient's condition deteriorated.(ABSTRACT TRUNCATED AT 250 WORDS)