Exhaled nitric oxide in healthy young children during tidal breathing through a facemask

The aim of this study was to establish reference values and to examine day-to-day and within-day variations of exhaled nitric oxide (eNO) during tidal breathing in healthy children using a newly described method. Exhaled NO was measured on-line and off-line during tidal breathing through a facemask. In a subgroup of children measurements were repeated during the course of a single day and on the same time on three consecutive days. A total of 133 healthy children were included in the study and measurements were obtained from 121 children aged 2-7 yr (61 boys and 60 girls). The geometric mean eNO concentration and 95% CI was 3.9 (3.5-4.2) parts per billion (p.p.b.) for on-line measurements and 3.0 (2.7-3.3) p.p.b. for off-line measurements. Exhaled NO was independent of gender, age, height and weight. The 95% reference intervals (RI) for on-line and off-line measurements were 1.2-8.2 and 1.3-7.1 p.p.b. respectively. Twenty-three children completed measurements of within-day and day-to-day variations, none of which showed significant variation. In conclusion, the established reference values and data on variability within and between days may facilitate the clinical application for measurement of eNO during tidal breathing in young children.     

Tidal off-line exhaled nitric oxide measurements in a pre-school population

Exhaled nitric oxide (ENO) is used as a non-invasive marker of airway inflammation. The aim of this study was to measure ENO in a pre-school population using a relatively novel method, the off-line tidal breathing method, and to investigate differences in ENO between subjects with different presentations of wheezing. ENO was measured in 129 children (median age 4.4 years, quartiles 4.0-4.8 years) through a mouth mask attached to a two-way valve with an expiratory resistance of 5 cm H(2)0. Mean tidal ENO concentration (tENO) was calculated from triplicate measurements. Mean +/- SEM tENO for 89 control subjects was 13+/-0.4 ppb (95%CI 11.8-13.7 ppb); this level was significantly different from tENO in 15 children with a history of recurrent wheezing (18.6+/-1.9 ppb; 95%CI 14.5-22.7 ppb; t-test P<0.0001). Mean tENO in 16 children with a single wheezing episode was 11.4+/-1.0 ppb (95%CI 9.2-13.6 ppb) and thus significantly different from the recurrent wheezing group (t-test P=0.0024). CONCLUSION: The off-line tidal breathing method is a feasible and appealing method for measuring exhaled nitric oxide in pre-school children. With this method, higher tidal exhaled nitric oxide levels were found in children with recurrent wheezing.     

A methodology for measurements of nasal nitric oxide in children under 5 yr

Measurements of nasal nitric oxide (nNO) may give insight into respiratory conditions in children aged under 5 yr but no methodology has been described for this age-group. The present study aimed to establish the methodology and reproducibility for measuring nNO during tidal breathing in young children and to relate nNO to allergic conditions. Children and siblings aged under 5 yr attending hospital clinics were enrolled. On-line nNO measurements were obtained during tidal breathing using a chemiluminescence analyser. To establish our methodology, nNO was measured over 3, 5 or 10 s NO plateaus and nNO was also measured from left and right nostrils. nNO was then compared between children with and without allergic conditions. The reproducibility of nNO measurements over 24 h was studied in a separate group of children. Eighty-three children participated in the methodological part of the study and nNO was successfully measured in 57 (69%), mean (s.d.) age 3.4 (1.1) years, 14 with allergic conditions. Neither NO plateau duration nor choice of nostril influenced nNO values. The mean (s.d.) nNO for non-atopic children was 208 (103) parts per billion (ppb) and for atopic children was 284 (122), p = 0.032. Nasal NO values were not related to ambient NO, gender and passive smoke exposure; there was a non-significant trend for nNO to be positively related to age. Nasal NO measurements were reproducible in the 21 children tested, mean difference 9.6 ppb (limits of agreement-127, 146). We report a methodology for nNO measurement in young children. Further work is now required to establish the clinical utility of nNO in this age-group.     

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??Objective??To compare the FeNO??Fractional exhaled nitric oxide??FeNO??of the children 3-5 years old by facemask with that by mouthpieces during tidal breathing??and to analyze the applicative value of the measurement for the children 3 to 5 years old. Methods??From Junuary 2016 to August 2016??the children who came to Guangzhou Women’s and Children’s Medical Center to take the FeNO experiment were selected as the research subjects. During tidal breathing??children used the facemask to cover their nose and mouth to breath??or word the nose clip and used the mouthpieces to breath during the FeNO test. After the test??the clinical data were summarized and analyzed. Results??The cases??which have no coughing and wheezing symptoms??whether with rhinitis or not??currently using the mouthpieces to measure the FeNO??were fewer than which using the facemask. The result of using mouthpieces and facemask to test in children with rhinitis was ??7.8±10.6?? ×10-9 vs. ??15.8±9.9?? ×10-9 and??without rhinitis it was ??5.0±4.5?? ×10-9 vs. ??14.0±10.0?? ×10-9 respectively??P??0.05. The children having coughing or wheezing symptoms??whether with rhinitis or not??using the mouthpieces to measure the FeNO?? was fewer than those using the facemask. The result of using mouthpieces and facemask to test in children with rhinitis was 6.1×10-9???2.1??16.3?? ×10-9 vs. 11.6×10-9???4.1??26.5?? ×10-9?? and in those without rhinitis it was 4.6×10-9???1.9??9.9?? ×10-9?? vs. 11.5×10-9???6.5??25.8?? ×10-9?? respectively??P??0.05. All of them were statistically different. Conclusion??When we measure the FeNO in children from 3 to 5 years old during tidal breathing??breathing through the mouthpieces can reflect the airway inflammation better.     

Flow dependency and off-line measurement of exhaled NO in children

Levels of exhaled nitric oxide (eNO) are flow-dependent, and the choice of an optimal flow rate for off-line and on-line eNO measurement has raised much debate. Recently, a flow rate of 50 ml/s was recommended, but children younger than 5–6 years are not capable of stabilizing their expiratory flow at low flow rates. The power of off-line eNO values to discriminate between normal and atopic children was therefore evaluated at different exhalation flow rates. At flow rates of both 8.3 ml/s and of 350 ml/s, children (8–12 years) sensitive to house dust mite have two-fold higher eNO values (p < 0.001) as compared with children lacking such a sensitivity. The power of eNO to discriminate between normal and atopic subjects was similar at the two flow rates (no difference in AUC of receiver operation curves, p = 0.89). All children from 4.5 to 5 years of age (n = 29) could perform a single off-line exhalation manoeuvre at high (>350 ml/s) but not at low (8.3 ml/s) flow rates. At high exhalation flow rate, eNO was 7.1 ± 2.4 (mean ± SD) median, 6.5 p.p.b. with a mean variation coefficient of 5.5%. Depending on their developmental level, about half of the younger children (35–46 months of age) could perform an off-line exhalation manoeuvre at high flow rate with good reproducibility (mean variation coefficient of 6.6%). It is concluded that an exhalation flow rate of 350 ml/s is feasible to determine off-line eNO-values in children from 3.5 years of age, and that this high flow rate does not compromise the power of eNO to detect allergic disease.     

哮喘患儿呼出气一氧化氮及外周血嗜酸粒细胞的变化

目的：检测支气管哮喘（AS）,AS合并过敏性鼻炎（AS/AR）及慢性咳嗽变异性哮喘（CVA）患儿中呼出气一氧化氮（eNO）和外周血嗜酸粒细胞（EOS）的水平及两者的相关性,以探讨eNOS检测在AS儿童中的应用。方法：采用电化学法对5～14岁患有AS（n=12）、AS/AR（n=29）、CVA（n=10）的患儿进行eNO测定,同时测定EOS及一秒钟用力呼气容积占预计值百分比（FEV1％）。30例无特异性疾病史和家族过敏史,且近两周无急性呼吸道感染史的儿童作为对照组。结果：AS,AS/AR,CVA 3组eNO和EOS水平均高于对照组（P＜0.01）;AS/AR组eNO（50.3±6.7 ppb）和EOS水平（5.9±4.2×109）高于AS组（30.5±8.8 ppb,4.2±3.2×109）及CVA组（26.0±3.2 ppb,3.7±6.9×109）（均P＜0.05）,而AS、CVA组间差异无显著性;AS组eNO与EOS呈正相关（r＝0.51,P＜0.05）,但与FEV1无相关性（r＝0.144,P＞0.05）。结论：eNO在过敏性体质中高表达,且eNO可以反映AS患者气道嗜酸性炎症水平。［中国当代儿科杂志,2009,11（12）：986-988］     

Single breath analysis of endogenous nitric oxide in the newborn

Nitric oxide (NO) is found in the exhaled gas of humans immediately after birth. However, variations of endogenous NO concentration during the breathing cycle have not been studied in newborns. We examined 24 newborns without acute respiratory compromise during spontaneous nasal breathing. Gas was sampled from the tip of a thin nasal catheter placed in the hypopharynx. Endogenous NO concentrations measured by chemiluminescence were assigned to the breathing cycle using synchronized CO2 recording. Exhaled NO could reproducibly be measured at 1.9 +/- 0.2 parts per billion (ppb, mean +/- SEM). Autoinhaled nasal NO peaks during regular breathing were 12.0 +/- 1.7 ppb and reached intermittent maxima of 52.2 +/- 5.8 ppb. During regular breathing 6 infants exhibited sudden decreases of nasal NO peaks to periods with <50% amplitude suggesting transient shortage of autoinhaled nasal NO. We conclude that tidal NO analysis can be used to assess upper and lower airway NO production noninvasively during spontaneous breathing in the newborn.     

北京地区学龄儿童呼出气一氧化氮调查分析

目的 了解北京地区学龄儿童呼出气一氧化氮(eNO)水平.方法 选择北京市11-18岁在校学生,采用过敏件疾病与哮喘的国际间对比研究调查问卷,通过填写问卷及现场体检对儿童进行分组(正常儿童组及曾患不同疾病儿童组),检测eNO水平、峰流速及过敏原.结果 共筛选出正常儿童395名,男177名,女218名.不同性别正常儿童eNO差异无统计学意义(P均>0.05),但与其年龄呈正相关(男性P=0.008,女性P=0.05),在男性与其身高呈正相关(P=0.02).11～14岁、14～18岁正常儿童eNO几何均数(G)分别为11.22、14.13 ppb(ppb=10~9),其95%正常值范围分别为4.17～30.20 ppb、5.50～36.31 ppb.曾患哮喘/喘息(68例)和曾患过敏性鼻炎(96例)儿童eNO几何均数分别是19.05 ppb、14.79 ppb,与正常儿童差异有统计学意义(P分别为0.001、0.008).过敏原皮肤点刺检查阳性与阴性儿童eNO几何均数分别为16.98 ppb、11.75 ppb,两组间差异有统计学意义(P=0.001).结论 北京地区11～18岁正常学龄儿童eNO随年龄波动于10.72～13.80ppb,与年龄、身高呈正相关,与性别无关.喘息性疾病、过敏性鼻炎患儿以及特应性个体eNO水平显著增加.     

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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.     

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.     

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.     

在社区儿童哮喘诊断与管理中呼出气一氧化氮测定应用研究

目的 探讨呼出气一氧化氮（exhaled nitric oxide, eNO）体积分数在社区儿童的改变及对哮喘诊断与管理的价值。方法 2011年10月至2011年12月对来自北京西城区小学的7~12岁132例非哮喘儿童和93例哮喘儿童进行eNO测定、肺功能检测、过敏原皮肤点刺检查（skin prick test, SPT）以及病史询问和常规体检,观察eNO在社区非哮喘儿童和哮喘儿童的改变、影响因素及与临床情况的相关性。结果 非哮喘儿童与哮喘儿童eNO体积分数分别为（11.63±1.88）×10-9和（19.68±2.31）×10-9,其差异有统计学意义（P < 0.01）。在非哮喘儿童中,有鼻炎儿童的eNO为（17.49±2.02）×10-9,显著高于无鼻炎儿童（10.42±1.76）×10-9;特应性儿童的eNO为（16.12±1.98）×10-9,显著高于非特应性儿童（9.60±1.66）×10-9,差异均有统计学意义（P均 < 0.01）。在哮喘儿童中,伴有鼻炎与不伴有鼻炎儿童,其eNO水平分别为（19.54±2.31）×10-9、（20.09±2.25）×10-9,差异无统计学意义;但特应性儿童eNO水平显著高于非特应性儿童［分别为（23.06±2.18）×10-9、（8.75±1.86）×10-9,P < 0.01］;哮喘未控制儿童eNO为（25.09±2.31）×10-9,显著高于哮喘控制儿童［（17.21±2.22）×10-9,P < 0.05］;曾使用吸入激素与未曾使用吸入激素儿童,其eNO水平差异无统计学意义。无论是非哮喘儿童,还是哮喘儿童,其eNO水平与肺功能各参数间均无相关性。结论 eNO在社区特应性哮喘儿童中显著升高,并与哮喘控制与否有关。特应性是影响eNO水平的突出因素。在社区儿童中测定eNO有利于对儿童哮喘的进行早期诊断和分型,全面了解其过敏情况,从而改善哮喘的管理。     

Aerosol therapy: the special needs of young children

Efficient aerosol therapy in young children is a challenge. The aerosol administration method requires special features, because young children can not perform an inhalation manoeuvre, breath usually through the nose and may be distressed during the administration. The prescribing clinician should be aware of the advantages and disadvantages of the different inhalation devices available, in order to select the proper device for each individual patient. For maintenance asthma therapy in young children the pressurized metered dose inhaler (pMDI) combined with spacer is the first choice for delivering aerosols. A facemask can be attached if a child is unable to breath through the mouth. A small leak of the facemask can reduce the dose delivered dramatically, therefore a good seal is crucial. Lung deposition can be improved by using a pMDI with extra-fine particles. However, even if the most optimal device is chosen, cooperation during administration remains the most important determinant for efficient drug delivery. During crying the dose to the lungs is minimal. Optimal aerosol delivery to the lungs of young children can be achieved with a good facemask seal, good cooperation of the child, with quiet breathing and an aerosol with small particles.     

Exhaled nitric oxide levels in infants with chronic lung disease

Chronic lung disease (CLD) is an inflammatory disorder; in patients with other inflammatory disorders exhaled nitric oxide (NO) levels are elevated. The aim of this study was to test the hypothesis that prematurely born infants with CLD would have elevated exhaled NO levels compared to those without CLD and healthy term-born infants. Ten infants with CLD (median gestational age 26 weeks; CLD group), ten infants without CLD (median gestational age 32 weeks; non-CLD group) and ten term-born infants (term group) were examined at post-conceptional ages between 36 and 45 weeks. NO levels were measured during spontaneous tidal breathing. A facemask was positioned over the infants nose and mouth and a sampling catheter was inserted through a small leak-free valve into the facemask. To measure nasal NO, the tip of the sampling catheter was placed in the nasal space and to measure facemask NO, the catheter tip was positioned inside the facemask at the infants lips. Nasal compared to facemask NO levels were higher in all three groups (CLD; non-CLD; term: P =0.017, P =0.012 and P =0.017, respectively). The CLD group had higher peak nasal and facemask NO levels than the non-CLD ( P =0.011 and P =0.034 respectively) and the term ( P =0.005 and P =0.01 respectively) infants. Regression analysis demonstrated that facemask NO levels were significantly related to CLD, independent of gestational, post-natal and post-conceptional age ( P =0.006). Conclusion:our results suggest that exhaled nitric oxide levels are elevated in chronic lung disease infants. Facemask measurement of nitric oxide levels might be a potentially useful method to monitor infants with chronic lung disease.Abbreviations CLD chronic lung disease - NO nitric oxide     

CC chemokine receptor expression in childhood asthma is influenced by natural allergen exposure

Chemokines and their receptors may play an important role for leukocyte trafficking in allergic inflammation. Aim was to evaluate whether expression of chemokine receptors CCR4 and CCR8 on cells obtained by sputum induction from asthmatic allergic children may be influenced by house dust mite (HDM) allergen natural exposure. Twenty-one children (7-13 yr) with moderate asthma and sensitized to HDM were evaluated during a prolonged period of allergen avoidance (T0) and after a period of natural allergen exposure (T1). At each time point of sputum induction, lung function evaluation, exhaled nitric oxide (eNO) measurements were performed. At T1, CCR4 and CCR8 expression on sputum-induced cells increased from 28.4% +/- 2.9% and 25.8% +/- 1.9%, to 41.1% +/- 4.2% and 37.5% +/- 2.0%, respectively (p < 0.05 and p = 0.01). After allergen exposure, both sputum eosinophils (from 5.2% +/- 2.0% to 12.1% +/- 4.1%, p < 0.01) and eNO (from 15.1 +/- 2.2 ppb to 24.2 +/- 5.8 ppb, p < 0.05) showed significant increase. Lung function tests presented significant deterioration of Forced Expiratory Flow at 25-75% of Vital Capacity (FEF(25--75)) (p < 0.05) and increase of residual volume (p = 0.002). Significant changes in CC chemokine receptor expression in sputum-induced cells in asthmatic children in response to HDM exposure have been observed leading to consider the relevance of CCR4 and CCR8 in allergic asthmatic inflammation.     

Additive effect of eosinophilia and atopy on exhaled nitric oxide levels in children with or without a history of respiratory symptoms

Although atopy and blood eosinophilia both influence exhaled nitric oxide (eNO) measurements, no study has quantified their single or combined effect. We assessed the combined effect of atopy and blood eosinophilia on eNO in unselected schoolchildren. In 356 schoolchildren (boys/girls: 168/188) aged 9.0-11.5 yr, we determined eNO, total serum IgE, blood eosinophil counts and did skin prick tests (SPT) and spirometry. Parents completed a questionnaire on their children's current or past respiratory symptoms. Atopy was defined by a SPT >3 mm and eosinophilia by a blood cell count above the 80th percentile (>310 cells/ml). eNO levels were about twofold higher in atopic-eosinophilic subjects than in atopic subjects with low blood eosinophils [24.3 p.p.b. (parts per billion) vs. 14.1 p.p.b.] and than non-atopic subjects with high or low blood eosinophils (24.3 p.p.b. vs. 12.2 p.p.b. and 10.9 p.p.b.) (p <0.001 for both comparisons). The additive effect of atopy and high eosinophil count on eNO levels remained unchanged when subjects were analyzed separately by sex or by a positive history of wheeze (n=60), respiratory symptoms other than wheeze (n=107) or without respiratory symptoms (n=189). The frequency of sensitization to Dermatophagoides (Dpt or Dpf) was similar in atopic children with and without eosinophilia (66.2% and 67.4%, respectively); eosinophilia significantly increased eNO levels in Dp-sensitized children as well in children sensitized to other allergens. In a multiple linear regression analysis, eNO levels were mainly explained by the sum of positive SPT wheals and a high blood eosinophil count (t=4.8 and 4.3, p=0.000), but also by the presence of respiratory symptoms (especially wheeze) and male sex (t=2.6 and 2.0, p=0.009 and 0.045, respectively). Measuring eNO could be a simple, non-invasive method for identifying subjects at risk of asthma in unselected school populations.     

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.     

Airway nitric oxide in infants with acute wheezy bronchitis

Concentrations of nitric oxide (NO) in exhaled air are increased in children and adults with asthma, and NO measurements are used as a non-invasive marker to monitor airway inflammation in these patients. To define the role of NO in infants with acute wheezy bronchitis, we measured nasal and end-tidal NO concentrations in 17 infants with acute virus-associated wheezy bronchitis, in 22 term infants without respiratory disease, and in nine premature infants. Nasal NO measurements were performed with an olive placed in the infant's nose; end-tidal NO concentrations were assessed during tidal breathing through a snugly fitting face mask. Both end-tidal NO concentrations and nasal NO concentrations were reduced in infants with acute wheezy bronchitis. There were no differences in NO concentrations between term infants and premature infants. Measurements by both techniques were highly reproducible, as assessed by repeated measurements three times daily on three consecutive days in eight premature infants. Reduced airway NO concentrations in infants with virus-associated acute wheezy bronchitis are in contrast to findings in adults where both upper and lower airway NO levels are increased in patients with asthma. Whether this reflects a different inflammatory reaction to upper airway infections in acutely wheezy infants or pathophysiologic differences in airway response remains to be determined.     

气管支气管软化患儿潮气呼吸肺功能特征的研究

目的探讨气管支气管软化(TBM)患儿潮气呼吸肺功能的特征,为TBM患儿的诊断、疗效评估、预后判断提供新的思路。方法选取30例经电子支气管镜诊断为TBM的患儿作为研究组,30例健康儿童作为正常对照组。正常对照组和TBM组初诊时以及确诊后3个月、6个月、9个月、12个月进行潮气呼吸肺功能测定。结果 TBM确诊时与对照组在潮气量及吸气时间、呼气时间、吸呼比的差异无统计学意义(P0.05);与对照组比,TBM组确诊时的呼吸频率较快,达峰时间比和达峰容积比较低,差异具有统计学意义(P0.01);TBM患儿初诊时及确诊后3、6、9、12个月的潮气呼吸肺功能达峰时间比、达峰容积比逐渐增大。结论 TBM患儿潮气呼吸肺功能具有特征性改变,而且随着年龄增大,潮气呼吸肺功能逐渐接近正常。