Swimming pool attendance and exhaled nitric oxide in children.
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Publications and source records attributed to Eugenio Baraldi.
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RATIONALE: Acute exposure to chlorine gas results in respiratory impairment, but few data are available on the pathobiology of the underlying lung damage. OBJECTIVES: To assess lung function and potential lung damage pathways in the acute phase and longitudinally over a 15-mo follow-up after acute chlorine exposure. METHODS: Ten previously healthy children were accidentally exposed to chlorine gas at a swimming pool because of an erroneous servicing procedure. The fraction of nitric oxide in exhaled air (Fe(NO)), exhaled breath condensate compounds, and serum Clara cell-specific protein CC16 were repeatedly measured. MAIN RESULTS: In the acute phase, all patients had respiratory distress (one child required mechanical ventilation) and reduced lung function (median and interquartile range: FVC, 51 [43-60]% predicted; FEV(1), 51 [46-60]% predicted). This was accompanied by low Fe(NO) (4.7 [3.9-7.9] ppb), high exhaled breath condensate leukotriene B(4) (LTB(4)) levels (24.4 [22.5-24.9] pg/ml), and increased serum CC16 levels (mean +/- SEM, 23.4 +/- 2.5 microg/L). Lung function returned to normal in 15 d (FVC, 97% predicted [82-108], and FEV(1), 92% predicted [77-102]). Fe(NO) reached normal values after 2 mo (12.6 [11.4-15] ppb), whereas LTB(4) levels were still increased (12 [9.3-17.1] pg/ml). CONCLUSION: Children acutely exposed to chlorine in a swimming pool presented a substantial lung function impairment associated with biochemical exhaled breath alterations, represented mainly by an increase in LTB(4) and a reduction in Fe(NO). Although lung function and Fe(NO) improved within a few weeks, the increased levels of exhaled LTB(4) persisted for several months.
A growing interest has recently directed toward non invasive methods, such as exhaled nitric oxide (FE(NO)) measurement and exhaled breath condensate (EBC) collection, for the assessment of asthmatic inflammation. FE(NO) is a reliable marker of eosinophilic airway inflammation and it can be measured by means of a standardized technique in children starting from the age of 4. FE(NO) may have useful applications both in asthma diagnosis and monitoring. EBC is obtained cooling exhaled air and its composition is believed to mirror the characteristics of airway lining fluid. The compounds detected in EBC are markers of inflammation and oxidative stress occurring in asthmatic lung. While EBC is still only a research tool, FENO measurement is closer to clinical practice and lately it has been included in some treatment algorithms for asthma.
Exercise activity is an important part of daily life for both healthy children and children with respiratory diseases. Overall fitness level and responses to exercise can be assessed through cardiopulmonary exercise tests (using a treadmill or a cycloergometer). In asthmatic children exercise tests are useful to diagnose exercise-induced bronchoconstriction, which may affect up to 80% of asthmatic subjects. In cystic fibrosis patient, as the disease progresses, lung function deteriorates and exercise tolerance likewise diminishes. This reduced tolerance may not be predicted on the base of a standard spirometry while an exercise test can offer useful information. Eventually, exercise testing is useful in children with bronchopulmonary dysplasia to determine any presence and extent of gas exchange and ventilation dysfunction during exercise. Exercise challenges are a valuable tool to assess exercise tolerance that may be not adequately reflected by resting lung function tests.
This fourth paper in a review series on the role of lung function testing in infants and young children with acute neonatal disorders and chronic lung disease of infancy (CLDI) addresses measurements of forced expiration using rapid thoraco-abdominal compression (RTC) techniques and the forced deflation technique. Following orientation of the reader to the subject area, we focus our comments on the areas of inquiry proposed in the introductory paper to this series. The quality of the published literature is reviewed critically, and recommendations are provided to guide future investigation in this field. All studies on infants and young children with CLDI using forced expiratory or deflation maneuvers demonstrated that forced flows at low lung volume remain persistently low through the first 3 years of life. Measurement of maximal flow at functional residual capacity (V'maxFRC) is the most commonly used method for assessing airway function in infants, but is highly dependent on lung volume and airway tone. Recent studies suggested that the raised volume RTC technique, which assesses lung function over an extended volume range as in older children, may be a more sensitive means of discriminating changes in airway function in infants with respiratory disease. The forced deflation technique allows investigation of pulmonary function during the early development of CLDI in intubated subjects, but its invasive nature precludes its use in the routine setting. For all techniques, there is an urgent need to establish suitable reference data and evaluate within- and between-occasion repeatability, prior to establishing the clinical usefulness of these techniques in assessing baseline airway function and/or response to interventions in subjects with CLDI.
This seventh paper in a review series on different aspects of chronic lung disease following preterm birth focuses on the current knowledge of respiratory symptoms, airway function, airway hyperresponsiveness, and exercise capacity from childhood to adulthood. This paper further considers the long-term implications of these studies for both future research and clinical practice.
Leukotriene B(4) (LTB(4)) and interleukin-8 (IL-8) are inflammatory mediators involved in the neutrophil response to pulmonary bacterial colonization in cystic fibrosis (CF). The aim of this study was to investigate whether the LTB(4) and IL-8 levels in exhaled breath condensate (EBC) could be related to the type of bacterial colonization in CF patients. The pH level in EBC was analyzed as an estimate of airway acidification. Forty children were evaluated: 10 CF patients with P. aeruginosa, 10 CF patients with S. aureus, 10 not colonized CF patients, and 10 healthy children. LTB(4) and IL-8 in EBC were analyzed by specific enzyme immunoassay kits (EIA). The pH of EBC was measured with a pH-meter after deareation by bubbling with argon. Exhaled LTB(4) was higher in CF children with P. aeruginosa compared to those with S. aureus (P < 0.01), not colonized (P < 0.001), and healthy children (P < 0.01). Exhaled IL-8 was elevated in CF patients colonized by P. aeruginosa compared with other subgroups (vs. not colonized, P < 0.05; vs. healthy children, P < 0.001). IL-8 levels were higher in CF children with S. aureus than in healthy children (P < 0.05). There was an increase in IL-8 levels in not colonized CF patients compared with healthy children (P < 0.05). EBC pH was higher in healthy children compared to CF patients not colonized (P < 0.05). Our data suggest that EBC is suitable for evaluating neutrophil inflammatory mediators (LTB(4), IL-8, and pH) involved in the response to pulmonary bacterial colonization in CF children.
BACKGROUND: It is recognized that airway inflammation has a central role in the pathogenesis of asthma, but how it relates to exercise-induced bronchoconstriction (EIB) is not completely understood. OBJECTIVE: The aim of our study was to investigate the relationship between EIB and baseline concentrations of cysteinyl leukotrienes (Cys-LTs) and other inflammatory markers in exhaled breath condensate (EBC). METHODS: EBC was collected, and the fraction of exhaled nitric oxide (FE NO ) was measured in a group of 19 asthmatic children, after which they performed a treadmill exercise test. Fourteen healthy children were enrolled as control subjects. RESULTS: The asthmatic children were divided into the EIB group (decrease in FEV 1 , > or =12%) and the non-EIB group. The EBC was analyzed for the presence of Cys-LTs, leukotriene B 4 , and ammonia. Asthmatic patients with EIB (mean FEV 1 decrease, 23% +/- 3%) had higher Cys-LT concentrations than either asthmatic patients without EIB or control subjects (42.2 pg/mL [median] vs 11.7 pg/mL and 5.8 pg/mL; P < .05 and P < .001, respectively). Ammonia concentrations were lower in both the EIB and non-EIB groups than in control subjects (253.2 microM and 334.6 microM vs 798.4 microM; P < .01 and P < .05, respectively). No difference in EBC leukotriene B 4 levels was found among the 3 groups. Both asthmatic groups had higher FE NO levels than control subjects ( P < .001). EBC Cys-LT ( P < .01; r = 0.7) and FE NO ( P < .05; r = 0.5) values both correlated significantly with the postexercise FEV 1 decrease. CONCLUSION: this study shows that EBC Cys-LT values are higher in asthmatic children with EIB and correlate with the decrease in FEV 1 after exercise. These findings suggest that the pathways of both Cys-LT and nitric oxide are involved in the pathogenesis of EIB.
BACKGROUND: Fractional exhaled nitric oxide (FE NO ) is used in monitoring of asthma. OBJECTIVES: The aim of this multicenter study was to establish normal values of FE NO and assess feasibility in children with a standardized method and equipment approved for clinical use. METHODS: FE NO was measured in healthy subjects of 4 to 17 years according to American Thoracic Society guidelines (single breath online, exhalation flow 50 mL/s) with a chemiluminescence analyzer (NIOX Exhaled Nitric Oxide Monitoring System, Aerocrine, Sweden) in 3 European and 2 US centers. Each child performed 3 acceptable nitric oxide measurements within 6 attempts and completed an extended International Study of Asthma and Allergy in Children questionnaire. RESULTS: Measurement of FE NO was attempted in 522 children. Four hundred five children completed the study according to the protocol. Geometric mean FE NO in 405 children was 9.7 ppb, and the upper 95% confidence limit was 25.2 ppb. FE NO increased significantly with age, and higher FE NO was seen in children with self-reported rhinitis/conjunctivitis or hay fever. The success rate was age-dependent and improved from 40% in the children 4 years old to almost 100% from the age of 10 years. The repeatability of 3 approved measurements was 1.6 ppb (95% CI, 1.49-1.64 ppb). CONCLUSION: FE NO in healthy children is below 15 to 25 ppb depending on age and self-reported atopy. Measurement of FE NO by NIOX is simple and safe and has a good repeatability. Feasibility depends on age and may be difficult in the preschool child.
OBJECTIVE: The aim of this study was to investigate the validity of office spirometry in primary care pediatric practices. METHODS: Ten primary care pediatricians undertook a spirometry training program that was led by 2 pediatric pulmonologists from the Pediatric Department of the University of Padova. After the pediatricians' training, children with asthma or persistent cough underwent a spirometric test in the pediatrician's office and at a pulmonary function (PF) laboratory, in the same day in random order. Both spirometric tests were performed with a portable turbine flow sensor spirometer. We assessed the quality of the spirometric tests and compared a range of PF parameters obtained in the pediatricians' offices and in the PF laboratory according to the Bland and Altman method. RESULTS: A total of 109 children (mean age: 10.4 years; range: 6-15) were included in the study. Eighty-five (78%) of the spirometric tests that were performed in the pediatricians' offices met all of the acceptability and reproducibility criteria. The 24 unacceptable test results were attributable largely to a slow start and failure to satisfy end-of-test criteria. Only the 85 acceptable spirometric tests were considered for analysis. The agreement between the spirometric tests that were performed in the pediatrician's office and in the PF laboratory was good for the key parameters (forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow between 25% and 75%). The repeatability coefficient was 0.26 L for forced expiratory volume in 1 second (83 of 85 values fall within this range), 0.30 L for forced vital capacity (81 values fall within this range), and 0.58 L/s for forced expiratory flow between 25% and 75% (82 values fall within this range). In 79% of cases, the primary care pediatricians interpreted the spirometric tests correctly. CONCLUSIONS: It seems justifiable to perform spirometry in pediatric primary care, but an integrated approach involving both the primary care pediatrician and certified pediatric respiratory medicine centers is recommended because effective training and quality assurance are vital prerequisites for successful spirometry.
Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, may be associated with long-term airflow limitation. Survivors of BPD may develop asthma-like symptoms in childhood, with a variable response to beta(2)-agonists. However, the pathologic pathways underlying these respiratory manifestations are still unknown. The aim of this study was to measure exhaled nitric oxide (FE(NO)) and lung function in a group of 31 school-age survivors of BPD. They showed variable degrees of airflow obstruction (mean FEV(1) 77.8 +/- 2.3% predicted) unresponsive to beta(2)-agonists in 72% of the subjects. Their FE(NO) values (geometric mean [95% confidence interval]: 7.7 [+/- 1.1] ppb) were significantly lower than in a group of healthy matched control subjects born at term (10.7 [+/- 1.1] ppb, p < 0.05) and a group of preterm children without BPD (9.9 [+/- 1.1] ppb, p < 0.05). The children with BPD were also compared with a group of 31 patients with asthma with a comparable airflow limitation (FEV(1) 80.2 +/- 2.1% predicted) and showed FE(NO) values four times lower than in those with asthma (24.9 [+/- 1.2] ppb, p < 0.001). In conclusion, unlike children with asthma, school-age survivors of BPD have airflow limitation associated with low FE(NO) values and lack of reversibility to beta(2)-agonists, probably as a result of mechanisms related to early life structural changes in the airways.
BACKGROUND: Cysteinyl-leukotrienes (cys-LTs) and 8-isoprostane are biomarkers of airway inflammation and oxidative stress. OBJECTIVE: The aim of this study was to evaluate cys-LT and 8-isoprostane levels in exhaled breath condensate (EBC) of children with different degrees of asthma severity. METHODS: EBC was collected from 14 steroid-naive children with mild persistent asthma, 13 children with stable mild- to-moderate persistent asthma treated with inhaled corticosteroids (ICS), 9 ICS-treated children with unstable asthma, and 19 healthy children. RESULTS: In the three groups of asthmatic children, EBC concentrations of cys-LTs and 8-isoprostane were significantly higher than in control children (steroid-naive asthmatic children: cys-LTs median, 10.8 pg/mL, P <.001, 8-isoprostane, 16.2 pg/mL, P <.001; ICS-treated stable asthmatic children: cys-LTs, 12.7 pg/mL, P <.001, 8-isoprostane, 18.1 pg/mL, P <.001; children with unstable asthma: cys-LTs, 106.0 pg/mL, P <.01, 8-isoprostane, 29.7 pg/mL, P <.01; control children: cys-LTs, 4.3 pg/mL, 8-isoprostane, 3.5 pg/mL). Cys-LT levels were higher in children with unstable asthma than in the other two asthmatic groups (P <.05). FE(NO) levels were significantly higher in steroid-naive and in children with unstable asthma compared with ICS-treated children with stable asthma (P <.01). CONCLUSIONS: Our study shows that EBC cys-LTs and 8-isoprostane concentrations are higher in asthmatic children than in healthy control children, with scattered values in patients with unstable asthma. These findings suggest that EBC eicosanoid measurement may have useful clinical implications for investigating phenotype differences among asthmatic patients.
BACKGROUND/PURPOSE: In the last decades, several studies regarding cardiopulmonary sequelae in survivors of congenital diaphragmatic hernia (CDH) have been published, but results often are conflicting, and controversies still exist. The aim of this study was to assess cardiopulmonary anatomic and functional outcome in a group of long-term survivors of CDH of mild to moderate degree. METHODS: Twenty-four children aged 8.15 +/- 2.80 years underwent clinical examination with growth assessment, chest radiographs, echocardiography, pulmonary perfusion scintigraphy, static lung volumes measurement, and spirometry. RESULTS: Mean Z scores of weight for age and height for age were within normal values. Echocardiography showed normal anatomy and function in all but 3 patients with isolated CDH, in whom minor alterations were detected. Mean perfusion to the affected side was significantly lower (45.16 +/- 5.30%; P <.0001) but still within normal range. Four children showed a substantial impairment of perfusion to the hernia side. The mean spirometric values and pulmonary volumes were normal. However, a mild restrictive pattern was evident in 6 children (27.3%), an obstructive pattern in 3 (13.6%), and a mixed obstructive and restrictive impairment in 1. CONCLUSIONS: Hypoplastic lungs of mild to moderate CDH survivors continue to cause pulmonary morbidity in some children many years after the correction of the defect. In particular, lung perfusion appears to be impaired in 20% of the patients and pulmonary function in 45%, without any significant cardiac or developmental sequelae. The negative correlation between FEV1 and duration of ventilation at presentation (r = -0.49; P =.026) may be caused by the consequences of lung hypoplasia, but initial ventilatory management may contribute to increased pulmonary morbidity. Relationship between perfusion and FEF25-75 (r = 0.61; p = 0.004) could reflect an equivalent degree of reduction in the caliber of distal airways and pulmonary vascular tree.
Bronchopulmonary dysplasia is associated with abnormalities in lung function during infancy, yet many infants recover with no respiratory problems in the long term. We therefore did a longitudinal study of pulmonary function in 18 children with moderate to severe bronchopulmonary dysplasia. Forced expiratory volume in 1 s (FEV1) and forced mid-expiratory flow (FEF25-75) at school age were lower than normal in 15 of 18 children, and both showed a significant positive correlation with the maximal flow at functional residual capacity (Vmax(FRC)) at 24 months of age (r=0.68 and 0.85, respectively). Our results suggest that assessment of respiratory function during infancy can help to identify children with bronchopulmonary dysplasia at risk of incomplete recovery of respiratory function during childhood.
STUDY OBJECTIVE: To quantify lung oxidative stress in asthmatic children by measuring concentrations of 8-isoprostane, a marker of oxidative stress, in exhaled breath condensate (EBC), which is a noninvasive method of sampling airway secretions. Secondary objectives were as follows: (1) to measure levels of exhaled prostaglandin (PG) E(2), since impaired PGE(2) production has been implicated in the pathogenesis of asthma in adults; and (2) to measure levels of fractional exhaled nitric oxide (FeNO), which is a marker of airway inflammation. DESIGN: Single-center, cross-sectional study. PATIENTS: Twelve healthy children, 12 steroid-naïve asthmatic children, and 30 children in stable condition with mild-to-moderate persistent asthma who were being treated with inhaled corticosteroids (ICSs) [average dose, 300 micro g per day] were studied. INTERVENTIONS: Subjects attended the outpatient clinic on one occasion for the collection of EBC and FeNO measurements. MEASUREMENTS AND RESULTS: 8-Isoprostane and PGE(2) concentrations in EBC were measured with specific radioimmunoassays. FeNO was measured online by a chemiluminescence analyzer. 8-Isoprostane was detectable in the EBC of healthy children (mean [+/- SEM], 34.2 +/- 4.5 pg/mL), and its concentrations were increased in both steroid-naïve asthmatic children (mean, 56.4 +/- 7.7 pg/mL; p < 0.01) and steroid-treated asthmatic children (mean, 47.2 +/- 2.3 pg/mL; p < 0.05). There was no difference in exhaled 8-isoprostane concentrations between the two groups of asthmatic children (p = 0.14). By contrast, exhaled PGE(2) concentrations were similar among the three study groups (p = 0.56). FeNO levels were higher in steroid-naïve children with asthma (49.2 +/- 9.6 parts per billion [ppb]; p < 0.05) and, to a lesser extent, in steroid-treated asthmatic children (37.8 +/- 6.6 ppb; p < 0.05) compared with healthy children (15.2 +/- 1.7 ppb). CONCLUSIONS: Lung oxidative stress is increased in children who are in stable condition with asthma, as reflected by increased exhaled 8-isoprostane concentrations. This increase seems to be relatively resistant to treatment with ICSs. Decreased PGE(2) lung production is unlikely to play a pathophysiologic role in childhood asthma.
Oxidative stress is implicated in the pathogenesis of asthma, and clinical studies show an imbalance in the level of oxidants to the level of antioxidants in subjects with asthma. Aldehydes and glutathione are examples of biomarkers of oxidant-induced damage and antioxidant status in asthma, respectively. In the study, we applied analytical techniques based on liquid chromatography for the assessment of aldehydes and glutathione in the exhaled breath condensate of children with asthma and in control subjects without asthma. Twelve subjects with asthma were evaluated at exacerbation and after 5 days of therapy with prednisone. At exacerbation, malondialdehyde levels were higher in patients with asthma (30.2 +/- 2.4 nM) than in control subjects (19.4 +/- 1.9 nM, p = 0.002) and were reduced after steroid therapy (18.5 +/- 1.6 nM, p = 0.001). At exacerbation, glutathione levels were lower in subjects with asthma (5.96 +/- 0.6 nM) than in control subjects (14.1 +/- 0.8 nM, p < 0.0001) and were increased after the therapy (8.44 +/- 1.2 nM, p = 0.04). Malondialdehyde and glutathione both in subjects with asthma and control subjects were negatively correlated (r = -0.5, p = 0.001). The study shows that aldehydes and glutathione are detectable in the exhaled breath condensate of children with asthma and healthy children and that their levels are modified during asthma exacerbation and after a 5-day course of therapy with oral prednisone.
BACKGROUND: Fractional exhaled nitric oxide (FE(NO)) and exhaled carbon monoxide (ECO) have been proposed as markers of airway inflammation and oxidative stress. OBJECTIVE: The aim of this study was to assess the effect of oral prednisone treatment on FE(NO) and ECO levels in a group of 30 asthmatic children with asthma exacerbation. METHODS: Thirty asthmatic children with asthma exacerbation were treated with oral prednisone for 5 days (1 mg/kg/day). Before and after prednisone therapy, ECO was measured by means of a chemical analyzer and FE(NO) was measured by means of a chemiluminescence analyzer. ECO and FE(NO) were also measured in a group of healthy nonatopic children. RESULTS: Before therapy, both ECO values and FE(NO) values were higher in asthmatic children (ECO, 3.2 +/- 0.2 ppm; FE(NO) online, 74.9 +/- 6.2 ppb; FE(NO) offline, 20.2 +/- 1.4 ppb) than in healthy controls (ECO, 2.0 +/- 0.2 ppm [P <.01]; FE(NO) online, 10.1 +/- 0.8 [P <.0001]; FE(NO) offline, 5.9 +/- 0.4 ppb [P <.0001]). An overlap in ECO values was found between healthy controls and asthmatic children. After prednisone therapy, there was a significant reduction in FE(NO) values (FE(NO) online, 40.6 +/- 4.6 ppb [P <.0001]; FE(NO) offline, 11.1 +/- 0.8 ppb [P < 0.0001]) and a slight but nonsignificant decrease in ECO values (2.7 +/- 0.2 ppm [P = not significant]) in the asthmatic group. No significant correlation between ECO values and FE(NO) values was found in either the asthmatic children or the controls. CONCLUSIONS: After a course of prednisone therapy, in children with asthma exacerbation there is a significant decrease in FE(NO) but no significant change in ECO levels. This possibly suggests that ECO is less sensitive than FE(NO) to inhibition by corticosteroids.