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PubMed2003

Respiratory symptoms and peak expiratory flow in children with asthma in relation to volatile organic compounds in exhaled breath and ambient air.

Indoor volatile organic compounds (VOCs) have been associated with asthma, but there is little epidemiologic work on ambient exposures, and no data on relationships between respiratory health and exhaled breath VOCs, which is a biomarker of VOC exposure. We recruited 26 Hispanic children with mild asthma in a Los Angeles community with high VOC levels near major freeways and trucking routes. Two dropped out, three had invalid peak expiratory flow (PEF) or breath VOC data, leaving 21. Children filled out symptom diaries and performed PEF maneuvers daily, November 1999-January 2000. We aimed to collect breath VOC samples on asthma episode and baseline symptom-free days, but six subjects only gave samples on symptom-free days. We analyzed 106 breath samples by GC-MS. Eight VOCs were quantifiable in >75% of breath samples (benzene, methylene chloride, styrene, tetrachloroethylene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene). Generalized estimating equation and mixed linear regression models for VOC exposure-response relationships controlled for temperature and respiratory infections. We found marginally positive associations between bothersome or more severe asthma symptoms and same day breath concentrations of benzene [odds ratio (OR) 2.03, 95% confidence interval (CI) 0.80, 5.11] but not other breath VOCs. Ambient petroleum-related VOCs measured on the same person-days as breath VOCs showed notably stronger associations with symptoms, including toluene, m,p-xylene, o-xylene, and benzene (OR 5.93, 95% CI 1.64, 21.4). On breath sample days, symptoms were also associated with 1-h ambient NO(2), OR 8.13 (1.52, 43.4), and SO(2), OR 2.36 (1.16, 4.81). Consistent inverse relationships were found between evening PEF and the same ambient VOCs, NO(2), and SO(2). There were no associations with O(3). Given the high traffic density of the region, stronger associations for ambient than for breath VOCs suggest that ambient VOC measurements were better markers for daily exposure to combustion-related compounds thought to be causally related to acute asthma. Alternatively, the low sample size of symptom responses (15-21 responses per 108 breath samples) may have led to the nonsignificant results for breath VOCs.

Adolescent↗
PubMed2004

Exhaled breath condensate in children: pearls and pitfalls.

Exhaled breath condensate (EBC) is a rapidly growing field of research in respiratory medicine. Airway inflammation is a central feature of chronic lung diseases, like asthma, cystic fibrosis, bronchopulmonary dysplasia and primary ciliary dyskinesia. EBC may be a useful technique for non-invasive assessment of markers of airway inflammation. The non-invasive character of EBC "inflammometry" and the general lack of appropriate techniques makes it particularly interesting for paediatrics. We provide a detailed update on the methods currently used for EBC collection and measurement of mediators. We emphasize on paediatric data. The apparent simplicity of the EBC method must not be overstated, as numerous methodological pitfalls have yet to overcome. Comparison and interpretation of data on this rapidly growing field of research is mainly hampered by the lack of standardization and the lack of specific high-sensitivity immunochemical or colorimetric assays. The initiative of the European Respiratory Society to institute a task force on this topic is a first step towards a uniform technique of EBC. Meanwhile, when using this technique or when interpreting research data, one should be fully aware of the possible methodological pitfalls.

Adolescent↗
PubMed2003

Interrelationships among asthma, atopy, rhinitis and exhaled nitric oxide in a population-based sample of children.

BACKGROUND: Exhaled nitric oxide (eNO) has attracted increasing interest as a non-invasive marker of airway inflammation in asthma. However, little evidence exists on the influences exerted on eNO by the interrelations among atopic status, asthma and rhinitis. METHODS: Among the 1156 children who participated in a large-scale epidemiological survey on asthma and allergies (ISAAC II: International Study of Asthma and Allergies in Childhood Phase II) in the city of Clermont-Ferrand, 53 asthmatics without corticosteroid treatment and 96 non-asthmatics were invited to perform eNO and skin prick tests (SPTs) to 12 common allergens. RESULTS: Atopic asthmatic children had higher eNO than non-atopic asthmatic children (28.9+/-9.1 vs. 17.1+/-13.1 p.p.b.; P=0.0004) with a significant increase when one SPT or more are positive (26.5+/-7.8 vs. 17.1+/-13.1 p.p.b.; P=0.03). Similarly, non-asthmatic, atopic subjects had higher eNO than non-atopic subjects with a significant increase when two SPTs or more are positive (19.4+/-9.8 vs. 11.7 +/-6.7 p.p.b.; P=0.003). In the case of equal levels of positive SPTs (0, 1, >/=2), asthmatic children always had higher eNO than non-asthmatic ones. Furthermore, among non-asthmatic children, the eNO level increased only in atopics who had rhinitis (20.7+/-13 vs. 12.5+/-6.4 p.p.b. in atopic controls (subjects without rhinitis and asthma) and 12.3+/-6.6 p.p.b. in non-atopic controls; P=0.001), whereas among asthmatic children, eNO level increased in atopics independently of rhinitis (28.2+/-9.5 p.p.b. in those with rhinitis and 30.9+/-8.1 p.p.b. in those without) as well as in non-atopics with rhinitis (22.5+/-17.2 p.p.b.). CONCLUSIONS: Our data suggest that besides atopy and asthma, allergic rhinitis should also be taken into account in the assessment of eNO.

Analysis of Variance↗
PubMed2000

Exhaled nitric oxide and its long-term variation in healthy non-smoking subjects.

Exhaled nitric oxide (NOexp) is an indicator of inflammation in the airways. Reference values obtained from healthy adults or information on long-term variation of NOexp are not yet available. The aims of this pilot study were to collect values of NOexp from a selected group of healthy adults and to assess their long-term variation. We studied 26 healthy subjects (age 21-48, 16 male, 10 female) with normal findings in flow-volume spirometry, pulmonary diffusing capacity, relative amount of blood eosinophils, chest X-ray and ECG at rest. NOexp was determined according to the European Respiratory Society guidelines during slow expiration against an airflow resistance. The measurements were repeated after 7 (n = 13) and 23 days (n = 17). The mean value of NOexp (n = 26) was 6.9 ng g-1 (95% confidence interval, 6.0-7.9 ng g-1). The upper limit of intra-individual variation (+2 SD) was 11.9 ng g-1 and the lower limit (-2 SD) 1.9 ng g-1, respectively. The mean (SD) value of NO production (NO output) was 39.1 pmol s-1 (20 pmol s-1). We found no correlation between NOexp and age (r = -0.06, P = 0.78) and no association of NOexp with the gender (male vs. female, P = 0.40). The intraindividual coefficient of variation (CoV) was 15.8% of NOexp and 20.7% of NO output within the interval of 7 days. CoV was 16.8% of NOexp and 18% of NO output within the interval 23 days. The results suggest that NOexp values over 12 ng g-1 are abnormally high in healthy subjects. According to the results the change of NOexp by 30-35% or more within the interval of 1-3 weeks would be abnormal.

Adult↗
PubMed2000

Exhaled nitric oxide during incremental and constant workload exercise in chronic cardiac failure.

BACKGROUND: Nitric oxide (NO) is present in exhaled breath and produced by the pulmonary vascular endothelium as a potent vasodilator. Exercise is normally associated with pulmonary vasodilatation and a decrease in pulmonary vascular resistance to accommodate the increase in cardiac output. If production of NO is impaired in patients with chronic congestive cardiac failure (CCF), this might contribute to their exercise intolerance. PATIENTS AND METHODS: We quantified NO production (V NO) in 12 patients with chronic stable CCF and 12 controls, at rest and during incremental cardiopulmonary exercise on a treadmill, and at a later date during constant workload exercise. RESULTS: Patients had reduced V NO compared with controls during incremental exercise [381 (180) vs. 777 (275) nL min-1; mean (SD); P < 0.0001] but at constant workload V NO was similar between the two groups [353 (124) vs. 389 (189) nL min-1; P = 0.25]. Plasma levels of nitrate, the stable end-product of NO production, were significantly higher in patients [resting value 46.1 (21.6) vs. 23.0 (10.0) microM; P = 0.004] and were not influenced by exercise. CONCLUSION: Impaired NO-mediated pulmonary vasodilatation does not appear to contribute to exercise limitation in CCF. Alternatively, the lower NO production observed during maximal exercise in the patient group compared with controls may reflect a reduced incremental response of a system that is already abnormally activated in heart failure.

Aged↗
PubMed2001

Increased nitric oxide in exhaled air after intake of a nitrate-rich meal.

Exhaled and nasal NO (ENO, NNO) have been suggested as markers for inflammation in lower and upper respiratory tract respectively. It is still unknown how a number of factors, apart from airway inflammation, can influence NO levels. The aim of this study was to determine the effect of a nitrate-rich meal on ENO and NNO. Sixteen healthy subjects were observed during 1 week on normal diet before a nitrate-restricted diet was introduced in the next. On day 3 of the second week they were made to ingest a nitrate rich meal. ENO, NNO, plasma nitrate and plasma L-arginine were followed before the meal and afterwards for 3 h. ENO and NNO as well as plasma nitrate and plasma L-arginine were significantly elevated after the nitrate-rich meal. The median maximal increase of ENO and NNO was 47% and 13% respectively. We found a moderate but significant correlation between the rise in plasma nitrate and ENO (r(s)=0.57, P=0.027) but none between plasma nitrate and NNO (r(s)=-0.02, P=0.95). As nitrate in the diet seems to substantially influence the levels of ENO it is important either to restrict or register the intake of nitrate-rich food prior to measuring ENO.

Adult↗
PubMed2001

Budesonide but not nedocromil sodium reduces exhaled nitric oxide levels in asthmatic children.

Exhaled nitric oxide (ENO) has been proposed as a marker of airway inflammation in asthma and could be useful to evaluate the response to anti-inflammatory treatment. We investigated the effect of budesonide and nedocromil sodium on ENO levels and lung function in asthmatic children. Twenty stable steroid-naïve asthmatic children were randomized in a single blind, cross-over study to receive inhaled budesonide (group A) or nedocromil sodium (group B) for 6 weeks. ENO was measured with a chemiluminescence analyser at baseline and at the end of each treatment period. Repeated-measures ANOVA was carried out. In asthmatic baseline ENO levels [mean 32.5 ppb, 95% confidence interval (CI) 26.4 to 38.7] were significantly higher compared to reference values (8.7 ppb, 95% CI 8.1 to 9.2, P<0.001). There were no treatment-order effect, no carry-over effect and in both groups the response pattern was the same: budesonide significantly lowered ENO levels from 41.0 ppb to 22.8 ppb in group A (mean, P<0.01) and from 22.6 ppb to 13.0 ppb in group B, (mean, P<0.05), while nedocromil did not reduce ENO values (from 24.4 ppb to 22.6 ppb in group B and from 22.8 ppb to 38.0 ppb in group A, mean, P = NS and P<0.01 respectively). After budesonide treatment ENO values of asthmatics were still significantly higher than in healthy children The baseline values of FEV1 and FEF(25-75) were normal in both groups and no significant changes were observed during the study. In conclusion, our study shows that budesonide, but not nedocromil sodium, significantly reduces ENO levels in stable asthmatic children even in absence of changes in the lung function.

Adolescent↗
PubMed2002

Exhaled nitric oxide and exercise tolerance in severe COPD patients.

To answer the question as to whether pulmonary rehabilitation programs (PRP) induced increase in exercise tolerance (ET) is associated with increased levels of exhaled nitric oxide (eNO) in COPD patients of different degrees of severity, we designed a prospective and controlled study. Forty-seven stable COPD patients underwent an 8-week outpatient multidisciplinary PRP including supervised incremental exercise. Fractional eNO concentration (FE(NO)) and peak work-rate (W(peak) were assessed baseline (T-1), atthe end of 1-month run-in period (T0), and after (T1) the PRP. Lung function, walking test, health-related quality of life (HRQL) were also recorded. Patients were divided into three groups according to disease severity: 17 severe [FEV1 35 (5)% pred] COPD patients, seven of them with cor pulmonale; 15 mild [FEV1 78 (6)% pred], and 15 moderate [FEV1 56 (6)% pred] COPD patients. FE(NO) did not differ at T-1 and T0 (mean absolute change (SD): 0.03 (0.09) 95% CI-0.01, 0.16, 0.06 (1.03) 95% CI 0.03, 0.75 and 0.05 (0.06) 95% CI 0.02, 0.11 ppb in mild, moderate and severe patients, respectively). As compared to T0, both W(peak) (by 17,15 and 10%, respectively) and FE(NO) (by 29, 24 and 16%, respectively) significantly increased in all groups, but not in patients with cor pulmonale. A significant correlation between pre- and post-PRP changes in Wpeak and FE(NO) was found both in mild to moderate (r = 0.79, P < 0.00001) and severe (r = 0.76, P < 0.001) COPD patients. After a PRP, improvement in ET is associated with an increase in eNO also in most severe COPD patients, but not in those with cor pulmonale.

Aged↗
PubMed2002

Short-term variability of exhaled nitric oxide in young male patients with mild asthma and in healthy subjects.

BACKGROUND: Exhaled nitric oxide (NOexp) is an indicator of eosinophilic airways inflammation. This study evaluated short-term variability of NOexp in 13 healthy subjects (19-41 years, eight males) and in 31 patients with asthmatic respiratory symptoms (19-21 years, all male) to obtain data for assessment of short-term changes of NOexp in clinical situations. METHODS: Mild asthma was confirmed in 10 patients (Group = asthma). Twenty-one patients with asthmatic respiratory symptoms did not fulfill the functional criteria of asthma (Group = respiratory symptoms). The procedure to determine NOexp followed the European Respiratory Society (ERS) guidelines; the mean expiratory flow used during sampling was 0.09-0.12 l/s. NOexp for each subject was determined as the mean of at least three successive measurements at the baseline, followed by determinations at 10 min, 6 h and 24 h after the baseline. RESULTS: At the baseline, the mean (SD) value of NOexp was 6.6 (2.3) parts per billion (ppb) in the healthy controls, and significantly higher both in patients with respiratory symptoms (14.6 (11) ppb, P = 0.0076) and in those with asthma (34.2 (43) ppb, P < 0.001). Intraclass correlation coefficient of NOexp measured at baseline and after an interval of 10 min was 0.959 in healthy subjects, 0.986 in patients with respiratory symptoms and 0.936 in asthma patients, respectively. Short-term variability in terms of coefficient of variation (CoV) of repeated measurements of NOexp at 10 min, 6 hand 24 h was 5.1, 10.8 and 11.7% in healthy subjects, 71, 16.4 and 22.2% in patients with respiratory symptoms and 13.5, 19.4 and 26.4% in asthma patients, respectively. CONCLUSIONS: Reproducibility of NOexp using standardized methods was good both in healthy subjects and in asthmatic patients. However, in asthmatics the short-term variation of NOexp was over two times as high as in healthy subjects. The level of NOexp was elevated, except in asthma, also in patients with asthmatic respiratory symptoms who did not fulfill the functional criteria of asthma.

Adult↗
PubMed2000

Mechanisms of sudden infant death and the contamination of inspired air with exhaled air.

The physiological effects on an infant of repeatedly sleeping in an environment consisting of a mixture of exhaled air and fresh air is examined. It is found that adaptation can be predicted. A possible outcome of the adaptation is shown to be the development of hypoxia when the conditions change during sleep from a state with carbon dioxide contamination of inspired air to one without. This hypoxia can be associated with apnoea: this apnoea can provide an explanation for some instances of sudden infant death. This explanation is consistent with the known epidemiology and environmental associations of a proportion of sudden infant death syndrome. Safety precautions for the prevention of re-breathing are given.

Air↗
PubMed2004

[Expired diagnosis?--the potential of exhaled breath analysis].

Analysis of breath condensate is an innovative approach to biochemical information from the lung. It provides a new tool to estimate and characterize the burden of oxidative and inflammatory processes in the airways/lung. Clinical applications in asthma, COPD and CF can be envisioned as well as determining organ-specific inflammation in mechanically ventilated patients or monitoring patients with transplanted lungs. However, besides inflammation other important areas have begun to be evaluated, such as the demonstration of p53 mutations in NSCLC patients or an increased ratio of EBC nitrite to tidal volume in mechanically stressed lungs. Of course a careful validation of each and every parameter is paramount to the use in clinical applications. The comparison to BAL is oftentimes called for but at the same time is not the comparison to a gold standard because of the well-known problems of BAL. The scope of this review is a summary of facts and theories concerning exhaled breath condensate generation, collection and analysis but at the same time the representation of the many aspects that remain to be resolved.

Breath Tests↗
PubMed2004

[Effect of two doses of budesonide on exhaled nitric oxide and urinary EPX excretion in asthmatic children].

The use of objective outcome measures that assess airway inflammation in pediatric asthma can provide a good evaluation of asthma severity and treatment response. In this double-blind and randomized study the effects of 200 micro g of budesonide and 800 micro g of budesonide on markers of inflammation (exhaled nitric oxide (eNO), eosinophil protein X (EPX) excretion in urine) and on lung function (FEV (1)) were prospectively investigated in 24 ICS-naive children with mild persistent to moderate persistent asthma over a period of eight weeks. After eight weeks of treatment 200 micro g and 800 micro g of budesonide led to a significant decrease (p < 0.025) in eNO [median (90 % interval): 200 micro g: - 17.2 ppb (- 54.6 to 0.9); 800 micro g: - 13.2 ppb (- 44.6 to - 1.7)]. A significant change in urinary EPX excretion was only observed in the high dose group [200 micro g: - 10.3 micro g/mmol creatinine (- 116.2 to 50.5), p = 0.9; 800 micro g: - 49.2 micro g/mmol creatinine (- 231.0 to 48.7), p = 0.02]. However, a significant difference between the change from baseline after 8 weeks of either group was found neither for eNO (p = 0.66) nor for EPX excretion (p = 0.04). In conclusion, our data demonstrate that 800 micro g budesonide per day did not show any advantage in reduction of airway inflammation, measured by eNO and urinary EPX excretion, in children with mild persistent to moderate persistent asthma.

Adolescent↗
PubMed1999

[13C-mixed triglyceride CO2 exhalation test. Investigation with an isotope selective, non dispersive infrared spectrophotometer of indirect function of the exocrine pancreas].

BACKGROUND AND OBJECTIVE: The 13C-mixed-triglyceride CO2-exhalation test (MTE) has been proposed for the noninvasive assessment of intraluminal duodenal pancreatic lipase activity. Up to now, stable isotope analysis of carbon dioxide of the MTE has been carried out with isotope ratio mass-spectrometry. The aim of the present study was to evaluate the MTE in patients with morphological signs of chronic pancreatitis (stages I-III) and exocrine pancreatic insufficiency by using an isotope-selective nondispersive infrared spectrometer (NDIRS). PATIENTS AND METHODS: 20 healthy volunteers (9 females, 11 males, age range 19-61 years) and 16 patients (7 females, 9 males, age range 33-76 years) were examined. After an overnight fast each patient received a solid-liquid test meal containing 250 mg 1,3 distearyl, 2[13C] octanoyl glycerol. Breath samples were obtained at baseline and at 30 min intervals over a period of 6 h after the test meal. The 13C/12C isotope ratio in each breath sample was determined by NDIRS as delta (%) and delta over baseline (%). Results were expressed as cumulative percentage dose of 13C recovered (cPDR) at 3, 4, 5, 6 h and maximal PDR (PDRpeak) (median; 5./95. percentile). RESULTS: Significant lower values concerning cPDR 3, 4, 5, 6 hours and PDRpeak [%] were found between healthy subjects and patients with chronic pancreatitis (p < 0.05): cPDR 6 h: 8.1 (0.4-20.5)% vs 29.1 (10.3-59.3)%; PDRpeak: 4.7 (0.4-10.2)% vs 9.2 (5.4-14.3)%. INTERPRETATION: In general, the MTE discriminates between healthy controls and patients with chronic pancreatitis and exocrine pancreatic insufficiency. However, the MTE using NDIRS cannot be recommended as a method of clinical routine because of marked data overlap between pathologic and normal values.

Adult↗
PubMed2005

Use of exhaled nitric oxide measurements to guide treatment in chronic asthma.

BACKGROUND: International guidelines for the treatment of asthma recommend adjusting the dose of inhaled corticosteroids on the basis of symptoms, bronchodilator requirements, and the results of pulmonary-function tests. Measurements of the fraction of exhaled nitric oxide (FE(NO)) constitute a noninvasive marker that may be a useful alternative for the adjustment of inhaled-corticosteroid treatment. METHODS: In a single-blind, placebo-controlled trial, we randomly assigned 97 patients with asthma who had been regularly receiving treatment with inhaled corticosteroids to have their corticosteroid dose adjusted, in a stepwise fashion, on the basis of either FE(NO) measurements or an algorithm based on conventional guidelines. After the optimal dose was determined (phase 1), patients were followed up for 12 months (phase 2). The primary outcome was the frequency of exacerbations of asthma; the secondary outcome was the mean daily dose of inhaled corticosteroid. RESULTS: Forty-six patients in the FE(NO) group and 48 in the group whose asthma was treated according to conventional guidelines (the control group) completed the study. The final mean daily doses of fluticasone, the inhaled corticosteroid that was used, were 370 microg per day for the FE(NO) group (95 percent confidence interval, 263 to 477) and 641 microg per day for the control group (95 percent confidence interval, 526 to 756; P=0.003), a difference of 270 microg per day (95 percent confidence interval, 112 to 430). The rates of exacerbation were 0.49 episode per patient per year in the FE(NO) group (95 percent confidence interval, 0.20 to 0.78) and 0.90 in the control group (95 percent confidence interval, 0.31 to 1.49), representing a nonsignificant reduction of 45.6 percent (95 percent confidence interval for mean difference, -78.6 percent to 54.5 percent) in the FE(NO) group. There were no significant differences in other markers of asthma control, use of oral prednisone, pulmonary function, or levels of airway inflammation (sputum eosinophils). CONCLUSIONS: With the use of FE(NO) measurements, maintenance doses of inhaled corticosteroids may be significantly reduced without compromising asthma control.

Administration, Inhalation↗
PubMed2000

A comparison of exhaled nitric oxide and induced sputum as markers of airway inflammation.

BACKGROUND: Exhaled nitric oxide (ENO) has been proposed as a noninvasive marker of airway inflammation in asthma. OBJECTIVE: We investigated the relationships among ENO, eosinophilic airway inflammation as measured by induced sputum, and physiologic parameters of disease severity (spirometry and methacholine PC(20)). We also examined the effect of corticosteroid treatment and atopy on ENO levels and eosinophil counts in induced sputum. METHODS: Measurements were taken on one day in 22 healthy nonatopic subjects, 28 healthy atopic subjects, 38 asthmatic subjects not taking inhaled steroids, 35 asthmatic subjects taking inhaled steroids, and 8 subjects with eosinophilic bronchitis without asthma. RESULTS: ENO levels showed significant but weak correlations with eosinophil differential counts in the steroid-naive asthmatic and healthy atopic groups (r (s) < 0.05). ENO levels were significantly lower in the asthmatic subjects taking steroids compared with the asthmatic subjects not taking steroids, despite there being no difference in the sputum cell counts, and a tendency to increased airflow limitation. ENO levels and sputum eosinophil counts were equally good at differentiating from steroid-naive asthmatic subjects. ENO levels were consistently raised in subjects with eosinophilic bronchitis without asthma. Atopy had no effect on ENO levels in the healthy subjects. CONCLUSION: We conclude that ENO is likely to have limited utility as a surrogate clinical measurement for either the presence or severity of eosinophilic airway inflammation, except in steroid-naive subjects.

Administration, Inhalation↗
PubMed2002

Exhaled breath condensate: an evolving tool for noninvasive evaluation of lung disease.

Exhaled breath condensate (EBC) contains aerosolized airway lining fluid and volatile compounds that provide noninvasive indications of ongoing biochemical and inflammatory activities in the lung. Rapid increase in interest in EBC has resulted from the recognition that in lung disease this easily sampled fluid has measurable characteristics that differ prominently from health. These assays have provided evidence of airway and lung redox deviation, acid-base status, and degree and type of inflammation in acute and chronic asthma, chronic obstructive pulmonary disease, adult respiratory distress syndrome, occupational diseases, and cystic fibrosis. Characterized by uncertain and variable degrees of dilution, EBC does not provide precise assessment of individual solute concentrations within native airway lining fluid. However, it can provide useful information when concentrations differ substantially between health and disease or are based on ratios of solutes found in the sample. Because they can be used to measure the targets of modern therapy, EBC assays are likely to become integral components of future clinical studies, and after further technical work is accomplished, they might be used to diagnose and monitor therapy in individual patients.

Biomarkers↗
PubMed2003

Exposure and sensitization to indoor allergens: association with lung function, bronchial reactivity, and exhaled nitric oxide measures in asthma.

BACKGROUND: Exposure to high levels of allergens in sensitized asthmatic patients causes worsening of pulmonary function in experimental studies. Chronic exposure to lower, naturally occurring levels of allergens might increase the severity of asthma. OBJECTIVE: We sought to study the associations between sensitization and exposure to common indoor allergens (dust mite, cat, and dog) in the home on pulmonary function, exhaled nitric oxide (eNO), and airway reactivity in asthmatic patients. METHODS: Dust samples were collected from the living room carpet and mattress of 311 subject's homes, and Der p 1, Fel d 1, and Can f 1 concentrations were measured by using ELISAs. Spirometry, nonspecific bronchial reactivity, and eNO were measured. RESULTS: Subjects both sensitized and exposed to high levels of sensitizing allergen had significantly lower FEV(1) percent predicted values (mean, 83.7% vs 89.3%; mean difference, 5.6%; 95% CI, 0.6%-10.6%; P =.03), higher eNO values (geometric mean [GM], 12.8 vs 8.7 ppb; GM ratio, 0.7; 95% CI, 0.5-0.8; P =.001), and more severe airways reactivity (PD(20) GM, 0.25 vs 0.73 mg; GM ratio, 2.9; 95% CI, 1.6-5.0; P <.001) compared with subjects not sensitized and exposed. No significant effect of the interaction between sensitization and exposure was found for FEV(1) percent predicted and eNO values. However, there was a significant effect of the interaction between sensitization and exposure to any allergen (P =.05) and between sensitization and exposure to cat allergen (P =.04) for nonspecific bronchial reactivity. CONCLUSION: Asthmatic subjects who are exposed in their homes to allergens to which they are sensitized have a more severe form of the disease.

Adolescent↗
PubMed2001

A single dose of nebulized budesonide decreases exhaled nitric oxide in children with acute asthma.

This study was conducted to investigate whether a single dose of nebulized budesonide effectively decreased airway inflammation as demonstrated by exhaled nitric oxide (eNO) levels. A single dose of nebulized budesonide, but not nebulized terbutaline, rapidly decreased eNO levels in 6 hours. The decrease in eNO levels induced by nebulized budesonide was correlated to an increase in peak expiratory flow rate.

Adolescent↗