Comparison of exhaled nitric oxide analysers

SummaryCurrently no published data are available concerning the comparability of different types of NO analysers, making inter-laboratory comparisons difficult. In two sets of experiments we compared 4 and 5 NO analysers, respectively, from 3 different manufacturers using different calibration regimes: calibration with (1) a separate recommended calibration gas for each analyser, (2) a single low concentration for all (394ppb), and (3) a single high concentration (12.8ppm). We measured three subjects with known low (L), moderate (M) and high (H) bronchial exhaled nitric oxide concentrations as well as standard gases (SG). In the first set of experiments, calibration regime 1 resulted in the largest differences between analysers (coefficient of variation (CV) for L, M, H, SG: 0.42, 0.22, 0.20, 0.14). The lowest CV between analysers was observed after calibration 2 (0.34, 0.19, 0.12, 0.02). Very similar results were obtained in the second set of comparisons. Thus, differences between analysers existed, but were mainly due to differences in recommended calibration gases/procedures. Only a small part was explainable by deviations from target flow. These differences need to be taken into account when comparing data between laboratories or replacing the calibration gas of an analyser, as well as for the establishment and interpretation of normal values

Occupational rhinitis.

Occupational rhinitis (OR) has so far received little attention even though it shares common pathophysiological features and trigger factors and is closely associated with occupational asthma (OA). Work-related exposure to certain substances, such as animal dander, is considered to be the main factor for the development of OR. The new EAACI definition of OR stresses the causal relationship between workplace exposure and onset of rhinitis symptoms as opposed to previous definitions that mainly focused on a temporal relationship between workplace exposure and occurrence of nasal symptoms. Also, it has been suggested to use the term "work-related rhinitis" for classifying the different forms of rhinitis associated with the workplace. These forms can be subdivided into allergic or non-allergic OR, which is due to causes and conditions related to a particular work environment, as well as work-exacerbated rhinitis, which is defined as a pre-existing rhinitis exacerbated by exposure at the workplace. Even though taking a detailed patient history is especially important when it comes to diagnosing OR, the gold standard for confirming the diagnosis is nasal provocation testing. Best possible symptomatic relief and prevention of development of OA constitute the main therapeutic objectives in OR. Treatment options consist of total avoidance of trigger substances (main goal), reduction of exposure to certain substances, and pharmacotherapy. Furthermore, it is important to note that allergic OR is an occupational disease in Germany (Berufskrankheit No 4301) and needs to be reported to health authorities

Exercise training improves recovery in patients with COPD after an acute exacerbation

AbstractClinical experience suggests that exercise is beneficial for recovery after an acute exacerbation in patients with severe chronic obstructive pulmonary disease (COPD). The aim of this study was to quantify the clinical benefit of exercise in these patients.Twenty-nine inpatients were randomly assigned to a training group (n=15, FEV1 34% pred) or a control group (n=14, FEV1 38% pred). On ten consecutive days, patients in the training group performed a 6-min treadmill walking test and, in addition, five walking sessions per day at ≥75% of the respective treadmill walking distance. Patients in the control group performed only treadmill walking tests on days 1, 5, and 10. To directly compare the possible benefit of exercise training all patients had an exercise test on day 11 at the same work load as on day 1.In the training group, 6-min walking distance increased from 237 to 420 m, in the control group from 230 to 255 m over the 10 day period which was significantly different (P<0·0001). Minute ventilation and oxygen uptake increased significantly (P<0·05) in the training but not in the control group. When comparing exercise tests on days 1 and 11, minute ventilation, oxygen uptake, PaCO2, lactic acid concentration, and Borg scale were significantly reduced to achieve the same work load (P<0·01) only in the training group. Intrathoracic gas volume and residual volume decreased, and FEV1 and vital capacity increased in the training (P<0·05) but not in the control group.Our data demonstrate that exercise training significantly improves the exercise capacity in patients with severe COPD after an acute exacerbation of their disease

Trends in bronchial hyperresponsiveness, respiratory symptoms and lung function among adults: West and East West Germany.

AbstractPrevious studies have shown higher prevalences of bronchial hyperresponsiveness (BHR), respiratory symptoms and atopic sensitization among adults in Western Germany than in Eastern Germany. One of the aims of the joint project INGA (INdoor Factors and Genetics in Asthma) is to assess incidence, prevalence and trends for asthma, BHR and atopic diseases over a time period of 11 years (1990–2001) in the former West (Hamburg) and East Germany (Erfurt), with special reference to indoor exposure.INGA was designed as a case-control study following a cross-sectional study performed from 1990 to 1992 within the European Community Respiratory Health Survey (ECRHS). The database consisted of 1159 subjects in Hamburg and 731 subjects in Erfurt from the ECRHS (age 20–44). In 1995–1996, 107 cases (diagnosed asthma, positive specific serum IgE, positive skin prick or PD20FEV1≤2·0 mg methacholine at ECRHS) and 106 controls (none of the previous findings) participated in Hamburg (115 cases and 109 controls in Erfurt). The methodology was identical to the ECRHS and dose–response slopes (DRS) of the methacholine challenge were calculated as an index of responsiveness.In the control group, median values of DRS were 0·028% mg−1(1990–1992) and 0·044 (1995–1996) (P<0·01) in Erfurt. Corresponding values for Hamburg were 0·028 and 0·022 (NS). Corresponding values within the case groups were 0·041 and 0·049 (NS) for Erfurt, and 0·069 and 0·052 (P<0·05) for Hamburg.Thus, 4 years after the first survey, we found an increased BHR in the Erfurt control group while the bronchial responsiveness remained unchanged for the Hamburg group. These trends in BHR, which indicate the expected converging tendency between East and West Germany, have to be confirmed within the next INGA-survey in 2000–2001

Assessing physical activity in the daily life of cystic fibrosis patients.

Physical Activity (PA) plays an important role in the health and quality of life of cystic fibrosis (CF) patients, but little is known about their PA in daily living. With the use of accelerometers it is now possible to monitor activity profiles in detail. The goals of this study are to assess feasibility and acceptance of a longer-term use of accelerometers in daily living in CF patients, study the possibility of detecting changes in PA in relation to the patients&#39; clinical state and compare the findings between a CF and an age-matched healthy control group. We asked 15 CF patients to wear two accelerometers for 21 days and fill in a diary. Ten of them (age 21 to 40, mean 29.5 years) participated and delivered data that could be evaluated. We also recruited 10 age-matched control subjects. Data was processed for calculating usage time and features extracted to construct models of activity. The younger patients, particularly females, were concerned with fashion and style and considered wearing the sensors a challenge. Overall, the compliance of patients with CF seemed to be lower than reported for elder subjects in the literature. Time-series analysis of the data indicated characteristic patterns of PA over time, provided that data preprocessing and noise-filtering had been optimized. Further studies have to assess whether the continuous recording of PA yields additional clinical information in CF and in particular, whether it is possible to detect or even predict exacerbations in patients with CF or other diseases

Local nitric oxide levels reflect the degree of allergic airway inflammation after segmental allergen challenge in asthmatics

Nitric oxide (NO) levels are increased in the exhaled air of asthmatics. As NO levels correlate with allergic airway inflammation, NO measurement has been suggested for disease monitoring. In patients with asthma, we previously demonstrated that intrabronchial treatment with a natural porcine surfactant enhanced airway inflammation after segmental allergen provocation. We studied whether local levels of NO reflect the degree of allergic airway inflammation following segmental allergen challenge with or without surfactant pretreatment. Segmental NO, as well as nitrite and nitrate in bronchoalveolar lavage (BAL) fluid, was measured before and after segmental challenge with either saline, saline plus allergen, or surfactant plus allergen in 16 patients with asthma and five healthy subjects. The data were compared with inflammatory BAL cells. Segmental NO levels were increased after instillation of saline (p<0.05), or surfactant plus allergen in asthmatics (p<0.05), and values were higher after surfactant plus allergen compared to saline challenge. Nitrate BAL levels were not altered after saline challenge but increased after allergen challenge (p<0.05) and further raised by surfactant (p<0.05), whereas nitrite levels were not altered by any treatment. Segmental NO and nitrate levels correlated with the degree of eosinophilic airway inflammation, and nitrate levels also correlated with neutrophil and lymphocyte numbers in BAL. In healthy subjects, NO, nitrite, and nitrate were unaffected. Thus, segmental NO and nitrate levels reflect the degree of allergic airway inflammation in patients with asthma. Measurement of both markers can be useful in studies using segmental allergen provocation, to assess local effects of potential immunomodulators

In patients with chronic bronchitis a four week trial with inhaled steroids does not attenuate airway inflammation

AbstractSystemic corticosteroids have been recommended as a therapeutic option in patients with moderate to severe COPD. In an early stage of the disease, i.e. chronic bronchitis with mild or no airflow obstruction, a trial with inhaled steroids could reveal potential benefits, particularly in terms of a modulation of airway inflammation.We therefore investigated the effect of inhaled fluticasone (1000 μ g day−1) on markers of airway inflammation in 19 patients with chronic bronchitis (mean±SEM FEV1, 83·4±3·0% predicted; FEV1/VC, 67·5±2·4%) in a double-blind, cross-over, placebo-controlled manner. Visits were performed before and after two 4-week treatment periods, separated by a 4-week washout period. Lung function, the concentration of exhaled nitric oxide, differential cell counts in induced sputum and the number of cells positive for iNOS, as well as the levels of LDH, ECP, neutrophil elastase and IL-8 in sputum supernatants were determined.Although the total cell number decreased significantly after fluticasone (geometric mean 12·3 vs. 7·7×106/ml;P<0·05) it was not significantly different from the change observed after placebo (14·2 vs. 10·6×106/ml; n.s.). None of the other parameters showed statistically significant changes after fluticasone or placebo and the results did not depend on the presence of airway hyperresponsiveness.We conclude that in patients with chronic bronchitis short-term treatment with inhaled corticosterids did not improve lung function or inflammatory parameters to an extent which was statistically significant as compared to spontaneous variability