Effect of montelukast on exhaled NO in asthmatic children exposed to relevant allergens

The level of exhaled nitric oxide (FENO) is increased in house dust mite (HDM)-sensitized asthmatic children after exposure to HDM antigen, and inhaled steroids can prevent this increase. The aim of this study was to evaluate whether montelukast could prevent an increase in FENO levels in allergic asthmatic children after a brief period of exposure to relevant allergens. Sixteen children were evaluated at the residential house 'Istituto Pio XII' (Misurina, Bellunio, Italy) in the Italian Alps, a dust mite-free environment. FENO levels were evaluated before ( t ₀) and immediately after ( t ₁) the children were exposed to HDM allergens for 2 weeks in their homes at sea level. No significant difference in FENO was observed in the fluticasone-treated group of children after 2 weeks at sea level. In the group treated with montelukast, an increase in FENO was observed between t ₀ and t ₁, which failed to reach statistical significance. These preliminary data suggest that oral montelukast could be effective in preventing the relapse in airway inflammation in allergic asthmatic children who are occasionally exposed to relevant allergens for a short period of time.     

Cysteinyl-leukotrienes in nasal lavage fluid in children with asthma

The aim of this study was to investigate repeatability of cysteinyl-leukotrienes (cys-LT) measurements in nasal lavage fluid (NLF) and to determine if cys-LT levels in NLF are related to asthma severity in children. As a second outcome, we investigated if cys-LT in NLF reflect lower airway inflammation as assessed by exhaled NO measurement. To assess the repeatability of cys-LT measurements, two NLF samples were obtained from eight healthy controls 24 h apart. Sixty-nine asthmatic children (mean age; range: 12.8; 7.3–17.7 yr), which were grouped according to asthma severity were studied cross-sectionally on one occasion. Cys-LT in NLF were analyzed using a specific enzyme immunoassay, exhaled NO, and pulmonary function parameters were measured. The coefficient of repeatability for the repeated cys-LT measurements was 1.45 pg/ml. Cys-LT levels in NLF differed significantly between asthma severity groups (p < 0.001): mild intermittent: [median (IQR)] 6.88 pg/ml (2.00–27.87); mild persistent: 21.09 pg/ml (4.50–84.67); and moderate persistent asthmatics: 36.41 pg/ml (11.03–118.40). Concentration of cys-LT in NLF and exhaled NO was positively correlated (r = 0.85; p < 0.001). In conclusion, concentration of cys-LT in NLF correlates with asthma severity in children and is related to lower airway inflammation.     

Suppression of plasma matrix metalloproteinase-9 following montelukast treatment in childhood asthma

BACKGROUND: Montelukast and ketotifen are commonly prescribed anti-inflammatory medications used in the treatment of childhood asthma. METHODS: To investigate the modulation effect of montelukast and ketotifen, the levels of exhaled nitric oxide (eNO) and plasma matrix metalloproteinase-9 (MMP-9) were analyzed in a group of 30 children with mild persistent asthma. RESULTS: Patients on montelukast therapy for 8 weeks had significantly decreased levels of eNO and plasma MMP-9, which were associated with improved symptoms and enhanced peak expiratory flow but not significantly associated with increased level of tissue inhibitor metalloproteinase-1 (TIMP-1). In contrast, treatment with ketotifen produced no significant changes in these parameters until 4-6 weeks into the therapy and no effect on plasma MMP-9. CONCLUSION: Leukotriene antagonists, such as montelukast, may be better non-steroidal anti-inflammatory drugs for preventing airway inflammation in mild childhood asthma.     

Eicosanoids in exhaled breath condensates in the assessment of childhood asthma

The value of measurements of eicosanoids in exhaled breath condensate (EBC) for the evaluation of childhood asthma is still inconclusive most likely because of the limited value of the methods used. In this case–control study in 48 asthmatic and 20 healthy children, we aimed to characterize the baseline profile of the inflammatory mediators cysteinyl leukotrienes (cysLTs), 9_α11_βPGF₂, PGE₂, PGF_2α, 8‐isoprostane (8‐iso‐PGF_2α) within EBC in asthmatic compared with healthy children using new methods. In addition, we investigated their relation to other inflammatory markers. The assessment included collection of EBC, measurement of fractional exhaled nitric oxide (FE_NO) and evaluation of urinary excretion of leukotriene E_4. cysLTs were measured directly in EBC by radioimmunoassay and prostanoids were measured using gas chromatography negative‐ion chemical ionization mass spectrometry. Only cysLT levels were significantly higher in asthmatic compared with healthy children (p = 0.002). No significant differences in cysLTs were found between steroid naïve and patients receiving inhaled corticosteroids. In contrast, FE_NO was significantly higher in steroid naïve compared with steroid‐treated asthmatic and healthy children (p = 0.04 and 0.024, respectively). The diagnostic accuracy of cysLTs in EBC for asthma was 73.6% for the whole group and 78.2% for steroid‐naïve asthmatic children. The accuracy to classify asthmatic for FE_NO was poor (62.9%) for the whole group, but improved to 79.9% when only steroid‐naïve asthmatic children were taken into consideration. cysLTs in EBC is an inflammatory marker which distinguishes asthmatics, as a whole group, from healthy children.     

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??Objective To explore the change of exhaled nitric oxide ??eNO?? in children from community and its importance in asthma management. Methods The study was conducted from October 2011 to December 2011. Totally 133 non-asthmatic children and 94 asthmatic children aged 7~12 years old from elementary schools in Beijing Xicheng District were included in the study. The eNO?? skin prick test ??SPT???? lung function and physical examination were carried out and information of medical history was collected in all children. The eNO level between non-asthmatic children and asthmatic children?? and its association with atopy?? rhinitis?? lung function and asthma control were analyzed. Results eNO levels of non-asthmatic children and asthmatic children were 11.63±1.88 ppb?? and 19.68±2.31 ppb respectively and the difference between them was statistically significant ??P<0.01??. In non-asthmatic children?? the level of eNO in children with rhinitis was significantly higher than in children without rhinitis ???17.49±2.02??×10-9 vs. ??10.42±1.76??×10-9?? P<0.01?? and eNO level in atopic children was higher than non-atopic children ???23.06±2.18??×10-9 vs. ??9.60±1.66??×10-9?? P<0.01??. In asthmatic children?? the difference in eNO level was not significant in children with rhinitis and without rhinitis ???19.58±2.34??×10-9 vs. ??20.09±2.25??×10-9??? but the eNO levels in atopic children ??23.06±2.18??×10-9 was significantly higher than non-atopic children ???8.75±1.86??×10-9?? P<0.01??. The level of eNO of uncontrolled asthmatic children was significantly higher than controlled asthmatic children ???25.09±2.31??×10-9 vs. ??17.21±2.22??×10-9?? P<0.05??. There was no significant difference in eNO level between children who used and those who did not use inhaled corticosteroid. The eNO level was not related to lung function parameters either in non-asthmatic or in asthmatic children. Conclusion The eNO level increases significantly in children with asthma or rhinitis and is associated with asthma control status. Atopy is an important factor on eNO level as well. Measuring eNO level would help improve the diagnosis of asthma and atopy and management of asthma and rhinitis in children from community.     

Time efficacy of a single dose of montelukast on exercise-induced asthma in children

The aim of this study was to evaluate the timing of onset and the duration of action of a single oral-dose treatment with montelukast in comparison to placebo on exercise-induced asthma (EIA) in asthmatic children. Nineteen children (7–13 years) with stable asthma were evaluated. Patients undertook three consecutive treadmill exercise tests, respectively, 2, 12 and 24 h after a single-dose administration. A double-blind randomized, single-dose, placebo-controlled, crossover design was used. To assess bronchoconstriction after the exercise challenge, the maximal percentage fall in FEV₁ (ΔFEV₁) from the baseline value was considered. Two hours after dosing, ΔFEV₁ was −15.33  ±  2.93 for placebo and −13.33  ±  2.03 for montelukast. At 12 h, ΔFEV₁ was −18.69  ±  2.83 for placebo, −9.78  ±  1.85 for montelukast (p < 0.005). No difference was observed between placebo (ΔFEV₁−10.21  ±  2.07) and montelukast (ΔFEV₁−9.10  ±  2.02) at 24 h. Analysis of the degree of protection showed a significant efficacy of montelukast (p = 0.02) in comparison with placebo only at 12 h. Montelukast showed a significant protective effect 12 h after dosing, but no effect after 2 and 24 h. In mild asthmatics, the timing of administration of single dosage before exercise should be strictly considered in order to obtain the drug protective effects.     

以胸闷或长叹气为主诉的不典型哮喘儿童肺功能和呼出气一氧化氮特点分析

目的 分析以胸闷或长叹气为主诉的不典型哮喘儿童的肺功能和呼出气一氧化氮(fractional exhaled nitric oxide,FeNO)特点,并探讨FeNO在该类型哮喘患儿中的诊断价值.方法 选取2012年1月至2015年6月期间于我院儿童哮喘门诊确诊的以胸闷或长叹气为主诉的不典型哮喘儿童79例为研究对象(不典型哮喘组).该组患儿于初诊时均接受了肺功能检查、FeNO检测、血清总IgE和血清特异性IgE水平检测,且肺功能检测均存在支气管激发试验或支气管舒张试验阳性.同期选取我院完成FeNO检测的健康儿童100例作为对照组.分析不典型哮喘组初诊时肺功能特点和FeNO水平.采用受试者工作特征曲线(ROC)分析FeNO对于不典型哮喘儿童的诊断价值.结果 不典型哮喘组肺功能指标FEF50、FEF75、MMEF异常率分别为27％、43％、33％.FEV1％下降20％时吸入的乙酰甲胆碱累积剂量(PD20-FEV1)为0.41 (0.19～0.67)mg,该指标与MMEF呈显著正相关(r=0.301,P=0.007).不典型哮喘组Fe-NO值为13.0×10-9 (7.0×10-9～24.0×10-9),高于对照组且两者间存在统计学差异(P＜0.05).其Fe-NO值与总IgE水平呈显著正相关(r =0.672,P=0.001),与FEV1/FVC％、FEV1％ pred及PD20-FEV1均不存在相关性(P＞0.05).根据不典型哮喘儿童和健康儿童的FeNO值绘制ROC曲线,曲线下面积为0.60.结论 以胸闷或长叹气为主诉的哮喘儿童肺功能特点以小气道功能受损为主,其中MMEF下降明显者,其气道高反应更显著,FeNO检测对不典型哮喘诊断价值有限.     

特异质与慢性持续期哮喘儿童呼出气一氧化氮相关性研究

目的评估特异质对慢性持续期哮喘儿童呼出气一氧化氮(FeNO)水平的影响。方法选取同时完成皮肤点刺试验和FeNO检测的慢性持续期哮喘患儿52例,按皮肤点刺试验结果分为非特异质组和特异质组,按有无合并过敏性鼻炎分为鼻炎组和无鼻炎组;另选择78例健康儿童作为对照组,比较各组FeNO水平;并比较32例予吸入型糖皮质激素治疗3个月患儿的FeNO水平变化。结果 40例特异质组、12例非特异质组和对照组的FeNO水平差异有统计学意义(H=33.29,P=0.000);特异质组FeNO水平高于对照组和非特异质组,差异有统计学意义(P0.05)。11例无鼻炎组、41例鼻炎组和对照组的FeNO水平差异有统计学意义(H=30.63,P=0.000);鼻炎组FeNO水平高于对照组,差异有统计学意义(P0.05);鼻炎组与无鼻炎组差异无统计学意义(P0.05)。特异质组患儿FeNO水平与屋尘螨、粉尘螨皮肤点刺致敏风团直径无相关性(r=2.05、1.58,P均0.05)。32例患儿经吸入糖皮质激素治疗3个月后FeNO水平显著下降,与其治疗前第一次检测结果比较,差异有统计学意义(Z=2.05,P=0.041)。结论特异质对慢性持续期哮喘儿童FeNO水平有重要影响,吸入糖皮质激素可显著降低致敏哮喘儿童FeNO水平。     

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.     

Spirometry‐adjusted fraction of exhaled nitric oxide increases accuracy for assessment of asthma control in children

Spirometry and exhaled nitric oxide are two important complimentary tools to identify and assess asthma control in children. We aimed to determine the ability of a new suggested spirometry‐adjusted fraction of exhaled nitric oxide (NO) index in doing that. A random sample of 1602 schoolchildren were screened by a health questionnaire, skin prick tests, spirometry with bronchodilation and exhaled NO. A total of 662 children were included with median (IQR) exhaled NO 11(14) ppb. Receiver operating characteristic (ROC) curves using exhaled NO equations from Malmberg, Kovesi and Buchvald, and spirometry‐adjusted fraction of exhaled NO values were applied to identify asthmatic children and uncontrolled asthma. Receiver operating characteristic (ROC) curves failed to identify asthmatic children (all AUC < 0.700). Spirometry‐adjusted fraction of exhaled NO/FEV₁ (AUC = 0.712; P = .010) and NO/FEF_25%‐75% (AUC = 0.735 P = .004) had a fair and increased ability to identify uncontrolled disease compared with exhaled NO (AUC = 0.707; P = .011) or the Malmberg equation (AUC = 0.701; P = .014). Sensitivity and specificity identifying non‐controlled asthma were 59% and 81%, respectively, for the cut‐off value of 9.7 ppb/L for exhaled NO/FEV₁, and 40% and 100% for 15.7 ppb/L/s for exhaled NO/FEF_25%‐75%. Exhaled NO did not allow to identify childhood asthma. Spirometry‐adjusted fraction of exhaled NO performed better‐assessing asthma control in children. Thus, although more validation studies are needed, we suggest its use in epidemiological studies to assess asthma control.     

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。     

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.     

Exhaled nitric oxide in children with asthma and sinusitis

Exhaled nitric oxide (FE_NO) is a surrogate marker of eosinophilic airway inflammation. The measurement of this gas can be easily performed in children and the result is immediately available. Because of these characteristics, measurement of FE_NO is slowly becoming part of the routine clinical evaluation of an asthmatic patient. FE_NO measurement may have a role both in the diagnosis of asthma and as a guide in therapy algorithms. For example when FE_NO levels are persistently normal and the asthmatic child is asymptomatic, the steroid therapy may be decreased or even stopped. In patients with acute or chronic rhinosinusitis the levels of nasal nitric oxide (nNO) are significantly decreased, while they rise up after a course of antibiotics. The measurement of nasal NO has been proposed as a functional test to evaluate sinus ventilation. Nasal NO is significantly reduced also in primary ciliary dyskinesia and can be used as a screening tool to identify patients affected by this condition.     

肺功能检查及呼出气一氧化氮在儿童支气管哮喘规范化管理中的应用

目的探讨肺功能与呼出气一氧化氮(FeNO)在儿童支气管哮喘规范化治疗过程中的变化及意义。方法选取254例初诊、急性发作期的支气管哮喘患儿作为研究对象,按照有无合并过敏性鼻炎分为合并鼻炎组与未合并鼻炎组,并以62例健康儿童作为对照组。哮喘患儿均给予规范化治疗,于治疗初始以及治疗3、6、9、12个月复查肺功能及FeNO水平;对照组测定一次肺功能和FeNO。结果规范治疗1年中第1秒用力呼气容积(FEV1)、最高呼气流速(PEF)、最大呼气中段流量(MMEF),以及最大呼气25%、50%及75%肺活量的瞬间流速(MEF25、MEF50、MEF75)均逐渐升高,FeNO水平逐渐降低(P0.05)。治疗6个月后PEF、FEV1等大气道功能指标基本恢复;9个月后MMEF、MEF25、MEF50、MEF75等小气道功能指标基本恢复;1年后大小气道功能指标与对照组的差异均无统计学意义(P0.05),而FeNO水平仍高于对照组(P0.05)。治疗初始及3个月时,合并鼻炎组的哮喘患儿FeNO均高于未合并鼻炎组(P0.05)。治疗初始FeNO水平与肺功能各项指标均存在负相关(P0.05)。结论哮喘儿童的规范化治疗过程中,肺功能参数逐渐升高,FeNO水平逐渐下降,大气道功能的恢复早于小气道功能,另外也要注意鼻炎对气道反应性的影响。     

口鼻呼出气一氧化氮检测在儿童支气管哮喘控制评估及过敏性鼻炎诊断中的应用

目的 探讨口呼出气一氧化氮(fractional exhaled nitric oxide,FeNO)与鼻呼出气一氧化氮(nasal nitric oxide,nNO)检测值和儿童支气管哮喘(简称哮喘)控制水平的关系,以及对过敏性鼻炎的诊断价值.方法 以上海市儿童医院呼吸科门诊就诊的5～12岁哮喘和/或过敏性鼻炎患儿,...     

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目的将呼出气一氧化氮(FeNO)浓度检测与肺功能测定进行比较,评估其对儿童支气管哮喘诊断的临床价值。方法收集广州市儿童医院呼吸科门诊2009年6月至2010年5月反复咳嗽、间伴喘息等疑似支气管哮喘的患儿93例。使用FeNO测定仪(Medisoft HypairFeNo)进行测定,操作严格按照美国胸科协会制定指南进行;同时采用Medisoft hyp`Air型肺功能仪行基础肺功能检查,并进行支气管激发及舒张试验。根据结果并结合临床作为诊断儿童哮喘的标准,并以此作为FeNO诊断价值的参照,评价FeNO对支气管哮喘的鉴别诊断价值。结果 93例中激发试验阳性53例,支气管舒张试验阳性14例,结合临床最后均诊断为支气管哮喘。其余26例为激发试验阴性,诊断为非哮喘。哮喘组FeNO高于非哮喘组[(43.60±38.86)×10-9mol/L对(26.16±17.00)×10-9mol/L,P<0.05]。哮喘患儿FeNO与第1秒用力呼气容积(FEV1)占预计值百分比(FEV1%)之间无显著相关性(r=0.06,P>0.05)。激发试验阳性者FeNO值与PD20FEV1之间存在线性关系。结论 FeNO测定对支气管哮喘的诊断和鉴别诊断具有重要意义,但与肺功能、支气管激发试验检测相比仍存在一定局限性。     

呼出气一氧化氮浓度测定在儿童支气管哮喘和咳嗽变异性哮喘中的诊断价值

目的 分析呼出气一氧化氮(FeNO)对于支气管哮喘和咳嗽变异性哮喘的诊断价值,并探讨能否应用FeNO区分支气管哮喘和咳嗽变异性哮喘。方法 选取2012年6月至2014年6月150例初诊为支气管哮喘的患儿以及120例初诊为咳嗽变异性哮喘的患儿为研究对象,对两组患儿进行FeNO检测、肺功能检查以及支气管激发试验;同期选取150例健康儿童为对照组,对对照组儿童行FeNO检测。采用受试者工作特征曲线(ROC)分析FeNO对于支气管哮喘和咳嗽变异性哮喘的诊断价值。结果 支气管哮喘和咳嗽变异性哮喘组患儿的FeNO值均高于对照组(P< 0.01),支气管哮喘组的FeNO值显著高于咳嗽变异性哮喘组(P< 0.01);支气管哮喘组FEV1/FVC%、FEV1%pred、PD20较咳嗽变异性哮喘组均降低(P< 0.01)。FeNO诊断支气管哮喘的最佳阈值为19.5 ppb,敏感度为83.3%,特异度为86.7%;FeNO诊断咳嗽变异性哮喘的最佳阈值为15.5 ppb,敏感度为67.5%,特异度为78.0%;FeNO区别支气管哮喘和咳嗽变异性哮喘的最佳阈值为28.5 ppb,敏感度为60.7%,特异度为82.5%。结论 FeNO测定可用于支气管哮喘和咳嗽变异性哮喘的诊断和鉴别诊断。     

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目的通过对哮喘儿童呼出气一氧化氮(FENO)水平的监测,为哮喘的临床诊断治疗及病情评估提供帮助。方法选择2007年10月至2009年8月于首都儿科研究所附属儿童医院门诊确诊的哮喘患儿共358例,根据其哮喘发作与治疗情况分为哮喘发作组与非发作组、治疗组与未治疗组。设计临床观察表记录各组患儿治疗、发作、肺部喘鸣音情况,并进行FENO及1秒用力呼气容积(FEV1)、用力肺活量(FVC)及最大用力呼气中段流量(MMEF)等肺功能指标的测定。结果 358例哮喘患儿的FENO值为28.5(15.5～55.0)×10-9,其中男性为29.0(15.0～49.8.0)×10-9,女性为28.0(16.0～58.6)×10-9,男女相比差别无统计学意义(Z=-1.006,P>0.05)。111例11岁以上哮喘儿童FENO为36.0(20.0～65.0)×10-9,其中男性为30.0(26.0～63.0)×10-9,女性为40.5(17.7～73.8)×10-9,与395例正常儿童相比FENO明显增高,差异具有统计学意义(Z=-11.352,P<0.001)。358例哮喘患儿FENO与年龄呈正相关(r=0.206,P<0.01)...     

The effect of spirometry and exercise on exhaled nitric oxide in asthmatic children.

American Thoracic Society (ATS) guidelines recommend to refrain from spirometry or exercise before measuring fractional exhaled nitric oxide (FENO) because forced breathing maneuvers might influence FENO values. However the few studies already reported in children have given conflicting results. The aim of the study was to observe to what extent spirometry or exercise could affect FENO in asthmatic children. Twenty-four asthmatic children (mean age 12.8 yr) were enrolled. Measurements of FENO were performed before and 5, 15, 30, 45 and 60 min after spirometry or a 6-min walk test, on two separate days in random order. Geometric mean FENO at baseline was 25.6 parts per billion (ppb) before spirometry and 23.5 ppb before exercise. A small drop of FENO to 24.2 and 23.7 ppb was found 5 and 15 min after spirometry (both p = 0.04). After exercise, FENO values showed a larger drop to 18.5 ppb after 5 min and 20.7 ppb after 15 min (p < 0.001; p = 0.004 respectively). Changes in FENO occurred after exercise irrespective of baseline FENO and values returned to baseline within 30 min. We conclude that both spirometry and exercise affect FENO in asthmatic children. As the changes after exercise may lead to erroneous interpretations, children should refrain from physical exercise during at least 30 min before FENO measurements.