Daily ambulatory exhaled nitric oxide measurements in asthma

Exhaled NO (FENO) is a non-invasive, validated marker for asthmatic airway inflammation. Recently, a new hand-held NO-analyzer has been developed which makes it possible to monitor FENO at home. We assessed feasibility and analyzed variability of daily FENO home measurements. Twenty-one asthmatics (mean age 14.5 yr; range 8-25 yr) participated. Nineteen used a stable dose of inhaled corticosteroids and all of them were in a stable clinical condition. FENO was measured twice daily for 14 consecutive days. Measurements and symptom scores were recorded on a smart card in the analyzer. Symptom score items included well-being, wheeze, activity, and nocturnal symptoms. Measurements showed a success rate of 93%. We found a significant diurnal variation in FENO with geometric mean morning levels 14% higher than evening levels (95% CI: 4%-25%; p = 0.013). Individual subjects showed marked fluctuation of FENO. The mean intrasubject coefficient of variation of FENO was 40% for morning and 36% for evening values. FENO and cumulative symptom scores did not correlate. Home FENO measurements are feasible, and offer the possibility to asses airway inflammation on a daily basis. Further study is needed to interpret and evaluate possible benefits of FENO home monitoring.     

Methodological aspects of exhaled nitric oxide measurements in infants

Guidelines for the measurement of fractional exhaled nitric oxide (FE(NO)) recommend refraining from lung function tests (LFT) and certain foods and beverages before performing FE(NO) measurements, as they may lead to transiently altered FE(NO) levels. Little is known of such factors in infants. The aim of the present study was to evaluate whether forced expiratory maneuvers, sedation, nasal contamination, and breastfeeding affect FE(NO) values in infants. FE(NO) was measured off-line during tidal breathing by means of a facemask covering nose and mouth. FE(NO) measurements were performed in 45 sedated infants (mean age 12.1 months) who underwent LFT because of airway diseases and in 83 unsedated healthy infants (mean age 4.3 months). In infants with airway diseases, no difference was found in FE(NO) values before and 5 min after LFT (n = 19 infants, p = 0.7) and FE(NO) values before sedation did not differ from FE(NO) values during sedation (n = 10 infants, p = 0.2).Oral FE(NO) values were significantly lower than mixed (nasal + oral) FE(NO) (n = 42 infants, p < 0.001). FE(NO) values before and 5 min after breastfeeding were not different (n = 11 healthy infants, p = 0.57). The short-term reproducibility in healthy infants (n = 54) was satisfactory (intraclass correlation coefficient = 0.94). We conclude that, in infants with airway diseases, LFT prior to FE(NO) measurement did not influence FE(NO) values and FE(NO) values did not change after sedation. Oral FE(NO) values were significantly lower than mixed (oral + nasal) FE(NO), and breastfeeding did not influence FE(NO). Short-term reproducibility in awake healthy infants was good.     

儿童呼出气一氧化氮检测的临床应用

呼出气一氧化氮检测可反映气道嗜酸性粒细胞性炎症,近年来被广泛用于辅助支气管哮喘的诊断、监测支气管哮喘患者气道炎症以及监测患者对治疗效果的反应.呼出气一氧化氮检测作为一种无创性检查,能够得到成人及5岁以上儿童的高度配合,但在5岁以下儿童中的应用存在很多问题,目前国内尚缺乏婴幼儿及新生儿呼出气一氧化氮检测的正常值及相关大样本研究.该文主要从儿童呼出气一氧化氮检测的原理及方法、正常参考值、影响因素、临床应用等方面进行综述.     

呼出气一氧化氮浓度检测用于诊断儿童哮喘的临床评价

评价支气管哮喘(简称哮喘)气道炎症的"金标准"是支气管镜下行支气管内膜活检,但由于其操作复杂及创伤性较大,故在哮喘的监测中受到明显限制,尤其对儿童哮喘患者.     

Fractional exhaled nitric oxide and induced sputum

Conventional asthma management aimed at controlling the underlying airway inflammation is classically based on symptoms and lung function. More recently, various non invasive markers of airway inflammation have become available. The ideal measurement method should be safe, non-invasive, easy to perform, reproducible and accurate. Fractional exhaled nitric oxide (FeNO) measurements fulfil these criteria, however some issues concerning cut off values and clinical variability as well as the interpretation of high values in the absence of symptoms still need to be solved. Induced sputum measurements are more labour intensive, however have the advantage of providing direct, additional information on the current inflammatory status of the airways. The most frequently analysed marker is sputum eosinophil percentage, although other markers of inflammation have also been under investigation. Both methods, FeNO and induced sputum should be seen as complementary to the conventional tools such as spirometry and bronchial hyperresponsiveness (BHR) testing.     

呼出气一氧化氮在儿童哮喘中的临床价值

哮喘是一种气道慢性炎症性疾病,已成为儿童中最常见的慢性疾病之一.临床上对哮喘的诊断及治疗主要依据临床表现及肺功能,但两者并不能反映气道炎症.呼出气一氧化氮(exhaled nitric oxide,eNO)作为气道炎症的标志物,与气道炎症有显著相关性.eNO检测方法具有无创、简单、方便、特异性好等优点,在临床应用方面具有明显优势.该文介绍了NO在气道中的代谢及其作用,并从哮喘的诊断及鉴别诊断、哮喘管理方面阐述eNO检测在儿童哮喘临床应用中的研究进展.     

哮喘患儿呼出气一氧化氮的变化

目的观察哮喘患儿呼出气一氧化氮（ＮＯ）的变化。方法采用化学发光法对１２８名７～１２岁正常儿童和７６例６～１４岁哮喘患儿进行呼出气ＮＯ浓度测定，同时测定哮喘儿童一秒钟用力呼气容积（ＦＥＶ１）及其占预计值百分比（ＦＥＶ１％）。对其中２１例哮喘患儿进行治疗后８个月内随访，监测其呼出气ＮＯ浓度，采用组胺激发试验测定其治疗前和治疗６个月后气道反应性。结果哮喘患儿呼出气ＮＯ浓度为３９±２１ｐｐｂ，正常儿童呼出气ＮＯ浓度为２３±１３ｐｐｂ，两组差异有显著意义（Ｐ＜０．００１）；发作期哮喘患儿呼出气ＮＯ浓度略高于缓解期患儿，但差异无显著意义（４２±２４ｐｐｂ，３５±２１ｐｐｂ，Ｐ＞０．０５）；哮喘患儿呼出气ＮＯ浓度与ＦＥＶ１％无明显相关性（ｒ＝０．０９２，Ｐ＞０．０５）。１１例吸入糖皮质激素治疗的哮喘患儿治疗２周后缓解期呼出气ＮＯ浓度较治疗前降低（２７±９ｐｐｂ，４４±１８ｐｐｂ，Ｐ＜０．０５），治疗６个月后气道高反应性（ＡＨＲ）程度表现下降趋势，另１０例未用糖皮质激素治疗的患儿缓解期呼出气ＮＯ浓度和ＡＨＲ程度均无明显改变。结论哮喘患儿呼出气ＮＯ浓度高于正常，吸入糖皮质激素治疗可降低呼出气ＮＯ浓度和ＡＨＲ。     

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??Abstract??The pathophysiology of wheezing in infants is yet to be fully understood, and approaches for a confirmatory diagnosis of this condition remain so far limited. Thus, a combination of medical history and laboratory investigations represents the most reliable source of clinical clues for diagnosis and differential diagnosis of infant wheezing.     

Environmental exposures and exhaled nitric oxide in children with asthma

OBJECTIVE: To evaluate the relation of environmental factors with exhaled nitric oxide (FENO) concentrations among asthmatic children. STUDY DESIGN: Cross-sectional analysis of 170 tobacco smoke-exposed children, ages 6 to 12 years, who have doctor-diagnosed asthma using measures of FENO, medication use, and exposures to settled indoor allergens and tobacco smoke. RESULTS: In multivariable analysis, child's age, uncarpeted flooring, not owning a cat, higher income, dust mite exposure, and being sensitized to any allergens were associated with higher FENO concentrations. Children who were sensitized to indoor allergens had an adjusted geometric mean FENO of 15.4 ppb (95% CI, 13.1, 18.2) compared with 10 ppb (95% CI, 8.2, 12.2) for unsensitized children. There was no statistically significant association of serum cotinine, hair cotinine, or reported corticosteroid therapy with FENO. CONCLUSIONS: FENO is higher among children who are sensitized to indoor allergens and exposed to dust mites. The results hold promise for the use of FENO as a tool to manage childhood asthma by using both pharmacologic and environmental treatments.     

呼出气一氧化氮检测在幼儿支气管哮喘中的应用分析

目的分析各期支气管哮喘(AS)幼儿的呼出气一氧化氮(FeNO)浓度变化,探讨FeNO浓度与AS分期的相关性。方法选取2014年4~6月初次诊断为AS且处于急性发作期的1~3岁患儿58例为研究对象,依据治疗后病情转归情况分为慢性持续期(n=34)及临床缓解期(n=24),以同龄健康儿童30例为对照,对所有儿童行FeNO浓度、肺功能等检测。分析FeNO浓度与AS分期的相关性。利用受试者工作特征(ROC)曲线分析FeNO诊断AS的最佳诊断截点。结果各期AS患儿FeNO浓度均高于对照组儿童(P0.05)。急性发作期患儿Fe NO浓度高于慢性持续期和临床缓解期,且慢性持续期患儿FeNO浓度高于临床缓解期(均P0.05)。AS患儿FeNO浓度水平与AS分期相关(r=-0.382,P0.05)。ROC曲线分析显示FeNO诊断AS的最佳诊断截点为22.75 ppb,敏感度达0.933,但特异度仅为0.388。结论 AS幼儿FeNO浓度水平与AS分期相关;Fe NO浓度22.75 ppb可作诊断幼儿AS的界值。     

哮喘患儿治疗前后呼出气及血清一氧化氮含量的变化及临床意义

No abstract available     

哮喘患儿治疗前后呼出气及血清一氧化氮含量的变化及临床意义

<正>支气管哮喘(简称哮喘)是以气道的慢性炎症和非特异高反应性为特征,导致反复发作的喘息、呼吸困难、胸闷、咳嗽等临床症状,支气管镜下支气管灌洗液和支气管内膜活检的方法是检测评估气道炎症的金标准,但其有创性和较高的花费使其很难成     

Fractional exhaled nitric oxide in infants during cow's milk food challenge

Cow's milk allergy (CMA) is the most common food allergy in early childhood. The golden standard for the diagnosis of CMA is a food challenge after a period of elimination. Increased levels of fractional exhaled nitric oxide (FE_NO) have been shown after bronchial allergen provocation. We evaluated whether FE_NO may also be a predictor of a positive reaction during cow's milk challenge in infants. Forty-four infants [mean age (range): 4.2 (3.7–4.6) months] suspected of CMA underwent an open food challenge with cow's milk formula administered in ascending quantities, starting with 2 ml and then 6, 20, 60 and 200 ml until a clinical reaction occurred. Off-line FE_NO samples were obtained during tidal breathing by means of a facemask covering infants' nose and mouth. FE_NO was measured twice before the challenge (baseline), immediately before each new dose of milk and after a positive reaction or after the last dose of milk. Eleven children showed immediate positive clinical responses to cow's milk, whereas 13 infants presented only a late-type reaction. FE_NO values before or after a positive reaction (either immediate or late) were not different from FE_NO values at baseline. Baseline FE_NO in infants with a positive reaction did not differ from FE_NO in infants without a reaction at any time point. We conclude that FE_NO values are not predictive and not related to the occurrence of a positive reaction during a cow's milk challenge in infants, suggesting that a positive reaction may not result from eosinophilic activation.     

Montelukast decreased exhaled nitric oxide in children with perennial allergic rhinitis

BACKGROUND: Measurement of exhaled nitric oxide (eNO) is a simple and noninvasive method for assessment of inflammatory airway diseases. eNO is elevated in adolescent patients with perennial allergic rhinitis and related to bronchial hyperresponsiveness. The aim of this study was to investigate whether oral loratadine, montelukast, nasal budesonide or nasal sodium cromoglycate could reduce airway inflammation as indicated by decrease of eNO in children with perennial allergic rhinitis as demonstrated by eNO levels. METHODS: A randomized and investigator-blinded study was conducted in a hospital-based outpatient clinic. Children with perennial allergic rhinitis were divided into four groups and treated by loratadine, loratadine with nasal sodium cromoglycate, loratadine with oral montelukast, and loratadine with nasal budesonide, respectively. Allergic rhinitis scores, eNO and peak expiratory flow were measured before and 2, 4, 6 and 8 weeks after treatment. RESULTS: Results showed that eNO in children with perennial allergic rhinitis was reduced by nasal budesonide and oral montelukast within 2 weeks (24.56 +/- 14.42 vs 18.42 +/- 12.48, P < 0.001, in budesonide group; 27.81 +/- 13.4 vs 19.09 +/- 10.45, P < 0.001, in montelukast group), but not in the loratadine and cromoglycate groups. In contrast, loratadine or sodium cromoglycate also did not decrease eNO levels although they could decrease the symptom scores. CONCLUSIONS: It was concluded that four common treatment modalities could effectively release symptom scores, but decrease of airway inflammation as determined by decrease of eNO might be only achieved by nasal budesonide and montelukast, but not nasal sodium cromoglycate and loratadine. Children with perennial allergic rhinitis with high eNO levels may require oral montelukast or nasal budesonide treatment to prevent airway hyperresponsiveness.     

Consistently high levels of exhaled nitric oxide in children with asthma

Background: Exhaled nitric oxide (eNO) levels in children are unstable because they are regulated by many potent factors. The purpose of the current study was to evaluate the reliability of eNO levels between a long interval and other lung functions in normal and asthmatic children. Methods: Eighty‐three elementary school children (aged 11–12 years; male : female, 39 : 44) participated in this study. Lung function, airway resistance and eNO levels were measured twice: the first measurement was in autumn 2007, and the second was one year later. Results: There were 62 non‐asthmatic control children (male : female, 31 : 31) and 21 asthmatic children (male : female, 8 : 13). In both the first and the second examination, the levels of eNO in children with asthma were higher than those in children without asthma. The parameters of lung function and the respiratory resistance in children without asthma showed a good correlation between the results of the first and second examinations. The eNO level in non‐asthmatic children showed a good correlation between the two. On the other hand, the peripheral airway parameters of lung function and the respiratory resistance in children with asthma were not correlated between the first and the second examinations. The eNO level in these patients was well correlated between the two examinations. Conclusions: These data suggest that the eNO level showed good reproducibility in children with and without asthma. The eNO level is therefore considered to be a useful marker for reproducibly evaluating a subject's airway condition.     

Fractional exhaled nitric oxide in children with acute exacerbation of asthma

Objective

To determine whether fractional exhaled nitric oxide (FENO) has a utility as a diagnostic or predictive maker in acute exacerbations of asthma in children.

Design

Analysis of data collected in a pediatric asthma cohort.

Setting

Pediatric Chest Clinic of a tertiary care hospital

Methods

A cohort of children with asthma was followed up every 3 months in addition to any acute exacerbation visits. Pulmonary function tests (PFT) and FENO were obtained at all visits. We compared the FENO values during acute exacerbations with those at baseline and those during the follow up.

Results

243 asthmatic children were enrolled from August 2009 to December 2011 [mean (SD) follow up — 434 (227) days]. FENO during acute exacerbations was not different from FENO during follow up; however, FENO was significantly higher than personal best FENO during follow up (P < 0.0001). FENO during acute exacerbation did not correlate with the severity of acute exacerbation (P=0.29). The receiver operating characteristics curve for FENO as a marker for acute exacerbation had an area under the curve of 0.59. Cut-off of 20 ppb had a poor sensitivity (44%) and specificity (68.7%) for acute exacerbation.

Conclusions

FENO levels during acute exacerbation increase from their personal best levels. However, no particular cut off could be identified that could help in either diagnosing acute exacerbation or predicting its severity.