In this study, the authors attempted to validate answers to smoking-habit questions contained in the European Community Respiratory Health Survey questionnaire. The respondents were invited to visit the chest clinic at Verona, Italy, and their serum cotinine levels were measured. The authors invited each of 504 subjects to complete a respiratory interview and to give a blood sample for a radioimmunoassay serum cotinine measurement. A total of 375 subjects responded, of whom 129 were smokers (34.4%), 79 were exsmokers (21.1%), and 167 (44.5%) had never smoked. Exposure to environmental tobacco smoke was reported by 216 subjects (57.6% [mean exposure = 3.8 hr/day (+/- 3.4 hr/day standard deviation)]). In smokers, serum cotinine levels were directly related to the number of cigarettes smoked/day. The authors excluded from analysis nonsmokers who had serum cotinine levels that were > or = 14 ng/ml, and the resulting mean values were 1.7 ng/ml (+/- 2.1 ng/ml standard deviation) in nonsmokers unexposed to environmental tobacco smoke and 2.6 ng/ml (+/- 2.6 ng/ml standard deviation) (p < .002) in nonsmokers exposed to environmental tobacco smoke. There was a relationship between serum cotinine levels and hours of exposure to environmental tobacco smoke (R2 = .136, p < .05). Serum cotinine, which is an objective and accepted measure of tobacco exposure, confirmed the validity of the European Community Respiratory Health Survey questionnaire with respect to smoking habits and environmental tobacco smoke exposure.

The effects of body position (supine, right and left lateral decubitus) on gas exchange were evaluated in a patient with agenesis of the left pulmonary artery, subjected to mechanical ventilation because of adult respiratory distress syndrome. Arterial blood gases were measured 60 min after each of the three positions was attained and showed that lying on the left side (i.e. the side of the impaired lung) produced higher arterial oxygen pressure (68.5 ± 1.5 mm Hg) than lying on the opposite side (50.0 ± 1.2 mm Hg); (p < 0.05). No significant differences in mean arterial carbon dioxide pressure were found. In contrast to unilateral lung diseases affecting the parenchyma, the position improving arterial oxygenation was the one in which the healthy lung was uppermost, in our patient with a unilateral perfusion defect.

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Abstractthe daytime, the protective activity against methacholine during the 12 hours of the Background -Previous studies evaluating monitoring period being constant. Furspirometric values and symptoms have thermore there was no difference in the shown that once daily theophylline admean FEV 1 between the two treatments at ministered in the evening produces greater 14.00 and 20.00 hours. stabilisation of the airway function in asthConclusions -In adults with stable bronmatic patients than the prototype theochial asthma treatment with a single dose phylline given twice a day. The aim of of Diffumal-24 administered in the eventhis study was to compare the effects on ing improved airflow obstruction and rebronchial responsiveness to methacholine duced bronchial hyperresponsiveness. of an ultrasustained release theophylline (Thorax 1997;52:969-974) formulation (Diffumal-24, Malesci, Florence, Italy) administered once a day, a Keywords: theophylline, bronchial hyperresponsivesustained release theophylline formulation ness, bronchial asthma. (Theo-Dur, Recordati, Milan, Italy) administered twice a day, and placebo. Methods -The study was performed in 12 Oral theophylline formulations are widely used adult patients with asthma using a ran-in the treatment of bronchial asthma. During domised, double blind, three phase, cross-the past 10 years increased knowledge of the over design. Each phase lasted seven days pharmacokinetics, availability of theophylline and was followed or preceded by at least assays, and the development of sustained rethree days of theophylline washout. Diffu-lease formulations have led to a safer and more mal-24 was administered once a day at effective use of the drug.1 The therapeutic ad-20.00 hours whereas Theo-Dur was given vantages of sustained release formulations have twice a day at 08.00 hours and 20.00 hours. mainly been attributed to their ability to reduce In each patient the total daily dose of theo-fluctuations in plasma theophylline conphylline was the same during both phases. centrations and, consequently, to keep serum The dose of the two active preparations levels of the xanthine within the narrow therawas titrated to individual needs before the peutic range during the 24 hours.2 For this beginning of the study and then given in reason, slow release theophylline formulations divided or once daily doses. At 08.00, 14.00, given twice a day are theoretically more effectand 20.00 hours on day 7 of each phase ive than the more recently introduced ulserum theophylline concentrations were trasustained release theophylline formulations measured and spirometric tests (FEV 1 ) designed to allow once a day dosing which and bronchial challenge with metha-produce larger fluctuations in serum levels of choline were also performed. the xanthine.

This study investigated whether or not a sustained release formulation of theophylline (SRT) at different dosages had any effect on bronchial hyperresponsiveness as measured by the methacholine challenge. On four separate occasions, 16 patients with mild asthma took either placebo or 300,400, 500 mg of SRT twice a day. SRT had a slight bronchodilating effect that was not dose-related, but produced a dose-related decrease in the bronchial response to inhaled methacholine (r = 0.39, p = 0.007). This effect was present after all three treatment periods with the active drug when mean ± SE theophylline serum concentrations of 10.3 ± 0.7, 12.6 ± 0.9 and 17.1 ± 1.1 mg/l respectively were reached. A highly significant relationship between theophylline serum concentration and the degree of protection against methacholine bronchospasm was also found (r = 0.45, p = 0.001). It is concluded that oral theophylline does reduce bronchial hyperresponsiveness in a dose dependent fashion, this effect being present at all the serum concentrations within the normal range.