Role Of Exhaled Nitric Oxide Research Articles

Role of Exhaled Nitric Oxide in Management of Asthma in Pediatric Patients: A Systematic Review

Background: Fractional exhaled nitric oxide (FeNO) has emerged as a potential tool for managing asthma in children, but its precise role remains under investigation. Objectives: This systematic review aims to comprehensively evaluate the current research on FeNO's utility in managing pediatric asthma. Methods: We conducted a systematic search of electronic databases like PubMed, MEDLINE, Science Direct, and Scopus. Two independent reviewers screened and extracted data from eligible studies. Results: Sixteen studies including 4612 participants in total and more than half of them 2558 (55.5%) were males—were included in our data. Intermediate FeNO levels had a higher yearly hospitalization rate than those with low or high FeNO levels. FeNO can be a predictive marker as one study found that FeNO levels of more than 35 ppb have the highest risk of developing respiratory disease in the future. Regarding the benefits of FeNO-guided therapy, the use of FENO in conjunction with GINA guidelines for ICS titration can help reduce daily ICS doses and treatment costs. FeNO was found reliable as an asthma biomarker only in children with concomitant aeroallergen sensitivity. Conclusion: The evidence for the effectiveness of FeNO-guided asthma care in children is critical. The effect of FeNO-guided treatment on pharmaceutical use is unclear. Any benefits in illness control must be balanced against the risk of increased drug use, particularly ICS, as higher rates were frequently observed in children with FeNO-guided monitoring. There is an obvious need for larger, longer-term research to address these problems before making firm recommendations for routine therapeutic use.

The role of exhaled nitric oxide (FeNO) in the evaluation of lung parenchymal involvement in COVID-19 patients.

The inflammatory balance is an important factor in the clinical course of COVID-19 (SARS-CoV-2) infection, which has affected over 300 million people globally since its appearance in December 2019. This study aimed to evaluate the correlation between exhaled nitric oxide (FeNO) level and parenchymal involvement in COVID-19. The study included 106 patients with the delta variant of COVID-19 identified by real-time PCR as well as 40 healthy control groups between October 2021 and March 2022. The patients were analyzed in three groups: moderate COVID-19 (group 1), severe COVID-19 without macrophage activation syndrome (MAS) (group 2), and severe COVID-19 with MAS (group 3). FeNO and CT scores were significantly higher in groups 2 and 3 at admission and discharge compared to group 1 (p = 0.001 for all). In addition, CT score at admission and CT score and FeNO level at discharge were higher in group 3 than in group 2 (p = 0.001 for all). It was found that the FeNO levels were higher in Groups 2 and 3 than in the control group (p = 0.001) during the admission. FeNO and CT scores showed strong positive correlation at admission and discharge (r = 0.917, p = 0.001; r = 0.790, p = 0.001). In receiver operating characteristic curve analysis for prediction of MAS, FeNO at a cut-off of 10.5 ppb had 66% sensitivity and 71% specificity. COVID-19 causes more severe lung involvement than other viral lower respiratory tract infections, leading to the frequent use of chest CT in these patients. FeNO assessment is a practical and noninvasive method that may be useful in evaluating for parenchymal infiltration in the diagnosis and follow-up of COVID-19 patients.

Study of the role of exhaled nitric oxide (NO) in predicting controlled or uncontrolled asthma in asthmatic children.

BackgroundExhaled nitric oxide (NO), especially fractional concentration of exhaled NO (FENO) has been used to predict the responsiveness to inhaled corticosteroid (ICS) in children with asthma. However, the use of exhaled NO for predicting asthma control in children is still controversial.MethodsThis was a perspective observational study. Asthmatic children who were naïve to inhaled corticosteroid (ICS) were included in the present study. The measurements of FENO and CANO (concentration of NO in the gas phase of the alveolar), spirometry, blood eosinophil counts (BEC), and total IgE levels were done for each asthmatic child. All study subjects started proper asthma treatment after the enrollment.ResultsNinety three asthmatic children (9±3 years) with moderate (63.4%) to severe (36.6%) asthma were included and finished the 3-month study. The levels of FENO and CANO at inclusion were 37±11 ppb and 5.8±1.4 ppb, respectively; the mean of BEC was 617±258 cells/μL; the level of total IgE was 1563±576 UI/mL; 89% of subjects were positive for at least one respiratory allergen. The percentage of severe asthma was reduced significantly after 3 months (P<0.001). Well controlled asthma subjects at 3 months had higher levels of FENO and lower levels of CANO at inclusion (P<0.05 and P<0.05). FENO<20 ppb or CANO>5ppb had a risk of uncontrolled asthma at 3 months (OR: 1.7, CI 95% [(0.8) - (3.3)], P<0.05; OR: 1.9, CI 95% [(0.9) - (2.7)], P<0.05; respectively). FENO>35 ppb at inclusion had a positive predictive value for asthma control at 3 months (OR: 3.5, CI 95% [2.2-5.9], P<0.01).ConclusionsExhaled NO is a biomarker of asthma which may have a potential role to predict the control of asthma in short-term follow up in asthmatic children.

Study of the beneficial role of exhaled nitric oxide in combination with GINA guidelines for titration of inhaled corticosteroids in children with asthma

Background. The use of FENO in association with current guidelines in the treatment of asthma has not been studied thoroughly. This study aimed to evaluate the beneficial role of FENO in combination with GINA (Global Initiative for Asthma) guidelines for titration of inhaled corticosteroids (ICS) in asthmatic children. Methods. It was a prospective and descriptive study. Uncontrolled asthmatic children were randomized to two groups: group 1 (followed GINA guidelines) or group 2 (followed GINA guidelines + FENO modification for ICS titration). The two groups were followed-up for 12 months. Results. The mean age of the patients in the study was 10 ± 4 years for group 1 (n = 116) and 11 ± 5 years for group 2 (n = 108). There were 87.9% patients in group 1 and 82.4% in group 2 that had a familial allergic history. There were 58.6% of moderate asthma and 41.4% of severe asthma in group 1, versus 56.4% and 43.6% in group 2, respectively. The percentage of moderate and severe asthma was also significantly modified after 6th and 12th month versus at inclusion (43.1% and 35.3% versus 58.6%, P < 0.01 and P < 0.005; 23.2% and 12.9% versus 41.4%, P < 0.005 and P < 0.001, respectively). The total daily dose of ICS in group 2 at 12th months was significantly lower than that in group 1 (3515 ± 1175 versus 4785 ± 1235 mcg; P < 0.005). The daily cost of ICS treatment in group 2 was also lower than that of group 1 (18 ± 4 versus 27 ± 3 USD; P < 0.05). Conclusion. The use of FENO in combination with GINA guidelines for ICS titration is useful in reducing the daily ICS dose and treatment cost.

Elevated Levels of Alveolar Nitric Oxide May Indicate Presence of Small Airway Inflammation in Patients with Inflammatory Bowel Disease.

Pulmonary manifestations of inflammatory bowel disease (IBD), albeit not rare, are largely overlooked in clinical practice. The role of exhaled nitric oxide (eNO) as an established biological marker of airway inflammation compels us to use it as a tool to investigate the exact nature of these manifestations. Fractional eNO (FeNO) was measured in multiple flows, and with the use of a mathematical model, alveolar concentration of NO (CANO) and bronchial flux of NO (JawNO) were assessed in 27 patients with IBD [17 with Crohn's disease (CD) and 10 with ulcerative colitis (UC)] and in 39 healthy controls. Carefully selected criteria were used to exclude patients or healthy controls that presented factors considered to be correlated with eNO measurements. Disease activity was measured in Crohn's patients using the CD activity index (CDAI) score and in UC using the partial Mayo score. CANO was significantly higher in the IBD group, compared to the control group (p < 0.0001). FeNO was significantly increased in patients with IBD (p = 0.023), while there was no statistical significance found regarding levels of JawNO in patients with IBD (p = 0.106), both compared to controls. There was no significant correlation between any eNO component and markers of disease activity. Alveolar concentration of NO is elevated in patients with IBD, regardless of disease activity. This may suggest that subclinical small airway inflammation is present in patients with IBD, even those with mild or inactive disease.

Measurement of exhaled nitric oxide and serum surfactant protein D levels for monitoring radiation pneumonitis following thoracic radiotherapy

The present study aimed to examine the role of exhaled nitric oxide (eNO) and serum surfactant protein D (SP-D) level in the determination of radiation pneumonitis (RP) after thoracic radiotherapy (RT). The study included 34 treatments for 33 patients, including 16 three-dimensional conformal and 18 stereotactic body RT treatments. eNO levels were measured prior to RT, immediately subsequent to RT, every week during the RT course and at 1, 3, 6, 9 and 12 months following the treatment. The therapy reduced the eNO from 24.3±12.8 ppb prior to RT to 19.0±10.4 ppb immediately subsequent to RT (P=0.04). A total of 5 patients (14%) developed symptomatic RP of grade 2 or higher 3–5 months later, and exhibited an eNO elevation of 2.1±0.68-fold the minimum value, whereas the RP- group exhibited 1.4±0.6-fold elevation (P=0.02). The sensitivity of a cut-off of a 1.4-fold increase in the eNO ratio at the onset of RP was 100%; however, the specificity was 52%, and no predictive alterations to eNO levels were observed prior to the onset of RP. RT was associated with an elevated serum SP-D level at 3–6 months after RT. There was a statistically significant difference in the initial serum SP-D level between RP+ and RP- patients. In conclusion, obtaining the eNO ratio was a useful RP monitoring tool but did not predict RP occurrence in the present setting, whereas serum SP-D level may be a potential predictor for the detection of RP risk.

The role of exhaled nitric oxide in patients with chronic obstructive pulmonary disease undergoing laparotomy surgery – The noxious study

BackgroundChronic Obstructive Pulmonary Disease (COPD) has been associated with major perioperative morbidities or mortalities, especially in surgical patients receiving general anesthesia. The severity of the COPD and the degree of bronchial hyperreactivity can determine the perioperative anesthetic risk; therefore they have to be assessed by a thorough preoperative evaluation in order to give the rationale on which to decide for optimum anesthetic management. ObjectiveAim of the study was to assess the predictive applicability of exhaled Nitric Oxide (NO) in smoking surgical population with COPD, on the basis of morbidity and mortality. MethodsA prospective, observational study was undertaken in 70 smoking patients diagnosed with COPD scheduled for laparotomy surgery under general anesthesia COPD was evaluated with the GOLD Classification of Air Flow Limitation, the Modified MRC Dyspnoea Scale (mMRC), the BODE Index score and the 6 Minutes Walk Distance (6MWD) using spirometry parameters. All patients were observed for presenting perioperative and postoperative respiratory complications. A cut off value of 19 ppb was determined for fractional exhaled nitric oxide measured at expiratory flow of 50 mL/s (FENO50) to differentiate patients poor prognosis from those with favorable outcome. ResultsPatients with severe COPD had high BODE index score as well as FENO50. Elevated FENO50 is significantly related to multiple complications (p = 0.004) and postoperative cough (p < 0.001). Patients from the high FENO50 group that were not treated with steroids had a statistically significant higher incidence of extra hospital care need (p < 0.001). Increased FENO50 and ABCD classification are both related with the presentation of multiple complications (Odds ratio = 2.5, 95% CI 1.1 to 5.7, p = 0.028 for ABCD and Odds ratio = 6.39, 95% CI 1.33 to 30.5, p = 0.020 for FENO50). Increased FENO50 and ABCD are related with extra hospital care (p = 0.001 and p = 0.002 respectively) and combined with corticosteroid administration could predict the necessity for extra hospital care (Odds ratio 4.09, 95% CI 1.1 to 15.3, p = 0.036 for corticosteroid treatment, odds ratio 2.4, 95% CI 1.1 to 5.1, p = 0.029 for ABCD and odds ratio 7.93, 95% CI 1.7 to 35.3, p = 0.007 for FENO50). ConclusionThe FENO50 may identify high risk smoking surgical patients with COPD receiving general anesthesia. Perioperative and postoperative complications in COPD smoking patients undergoing abdominal surgery can be predicted using not only ABCD GOLD 2011 classification but also the FENO50 as a preoperative marker.

Exhaled nitric oxide predicts eosinophilic airway inflammation in COPD.

Chronic obstructive pulmonary disease (COPD) with eosinophilic airway inflammation may represent a unique phenotype, possibly with shared features of COPD and asthma. The role of exhaled nitric oxide (eNO) in identifying COPD patients with sputum eosinophilia was examined in this study. Ninety COPD patients without past medical history of asthma or allergic diseases were prospectively enrolled, and their eNO, lung function, and cellular profile of induced sputum were measured. Eosinophil cationic protein and IgE in sputum and venous blood also were determined. Subjects with and without sputum eosinophilia (>3 %) were compared. The role of eNO in the prediction of sputum eosinophilia was assessed in a logistic regression model. Patients with sputum eosinophilia had significantly higher levels of eNO (29 vs. 18 ppb, p = 0.01) than those without. The difference in serum total IgE (168 vs. 84.9 IU/ml, p = 0.057) and percentages of positive allergen test results (48.3 vs. 29.5 %, p = 0.082) showed a trend toward significance. The sputum eosinophil level was significantly correlated to the eNO level (r = 0.485, p < 0.001). The eNO level at the cutoff of 23.5 ppb had the maximum sum of sensitivity (62.1 %) and specificity (70.5 %). The unadjusted and adjusted odds ratios of a higher eNO level (>23.5 ppb) in the prediction of sputum eosinophilia were 3.909 (confidence interval (CI) 1.542-9.91, p = 0.004) and 4.329 (CI 1.306-14.356, p = 0.017), respectively. eNO is a good marker to identify COPD patients with eosinophilic airway inflammation.

Revisiting the role of exhaled nitric oxide in asthma

This review focuses on the most recent studies investigating fractional nitric oxide concentration in exhaled breath (FeNO) as a useful biomarker for identifying specific phenotypes in asthma and as a tool for asthma diagnosis, monitoring and clinical decision-making. On the basis of the current literature, it has been highlighted that FeNO is a clinically relevant marker in various clinical aspects of asthma: FeNO is a predictor for developing asthma in persistent rhinitis or in infants with respiratory symptoms; FeNO contributes to identification of asthma phenotypes in both children and adults, also in relation to severity; FeNO is useful in monitoring the effectiveness of inhaled corticosteroids (including compliance) and biologic treatments like omalizumab; FeNO, in conjunction with symptom registration and lung function measurements, contributes to asthma diagnosis and optimizes asthma management. FeNO provides further information in distinguishing different phenotypes in asthma, allowing a much more appropriate control of the disease, especially in patients with difficult/severe asthma. In the future, it would be interesting to shed light on the hidden biological mechanisms responsible for low or normal FeNO values in symptomatic asthmatic patients.

Role of exhaled nitric oxide as a predictor of atopy

BackgroundThe fractional exhaled nitric oxide (FeNO) is a quantitative, noninvasive and safe measure of airways inflammation that may complement the assessment of asthma. Elevations of FeNO have recently been found to correlate with allergic sensitization. Therefore, FeNO may be a useful predictor of atopy in the general population. We sought to determine the diagnostic accuracy of FeNO in predicting atopy in a population-based study.MethodsWe conducted a cross-sectional study in an age- and sex- stratified random sample of 13 to 15 year-olds in two communities in Peru. We asked participants about asthma symptoms, environmental exposures and sociodemographics, and underwent spirometry, assessment of FeNO and an allergy skin test. We used multivariable logistic regression to model the odds of atopy as a function of FeNO, and calculated area-under-the-curves (AUC) to determine the diagnostic accuracy of FeNO as a predictor of atopy.ResultsOf 1441 recruited participants, 1119 (83%) completed all evaluations. Mean FeNO was 17.6 ppb (SD=0.6) in atopics and 11.6 ppb (SD=0.8) in non-atopics (p<0.001). In multivariable analyses, a FeNO>20 ppb was associated with an increase in the odds of atopy in non-asthmatics (OR=5.3, 95% CI 3.3 to 8.5) and asthmatics (OR=16.2, 95% CI 3.4 to 77.5). A FeNO>20 ppb was the best predictor for atopy with an AUC of 68% (95% CI 64% to 69%). Stratified by asthma, the AUC was 65% (95% CI 61% to 69%) in non-asthmatics and 82% (95% CI 71% to 91%) in asthmatics.ConclusionsFeNO had limited accuracy to identify atopy among the general population; however, it may be a useful indicator of atopic phenotype among asthmatics.

The Role of Exhaled Nitric Oxide in Guiding Asthma Management

The Role of Exhaled Nitric Oxide in Guiding Asthma Management

The Role of Exhaled Nitric Oxide (FENO) in Eosinophilic Esophagitis: A Pilot Study to Evaluate the Correlation of Exhaled Nitric Oxide and Esophageal Eosinophils

The Role of Exhaled Nitric Oxide (FENO) in Eosinophilic Esophagitis: A Pilot Study to Evaluate the Correlation of Exhaled Nitric Oxide and Esophageal Eosinophils

Advances in asthma: the role of exhaled nitric oxide in the assessment and management of asthma

Advances in asthma: the role of exhaled nitric oxide in the assessment and management of asthma

Role of exhaled nitric oxide in predicting steroid response in chronic obstructive pulmonary disease

Exhaled nitric oxide is the most extensively studied exhaled biomarker. In patients with stable chronic obstructive pulmonary disease exhaled nitric oxide level appears to be normal or only slightly elevated. As exhaled nitric oxide is a good surrogate marker for eosinophilic airway inflammation and eosinophilic inflammation is steroid responsive, patients with elevated exhaled nitric oxide levels may benefit more from a short course of inhaled or systemic corticosteroid treatment. In acute exacerbation most studies report elevated exhaled nitric oxide levels that decrease along with treatment. More importantly, exhaled nitric oxide levels at exacerbation correlate with functional improvements after treatment suggesting the possibility of a role for exhaled nitric oxide in predicting the response to treatment. In conclusion, assessment of airway inflammation using exhaled nitric oxide may identify a subgroup of patients with chronic obstructive pulmonary disease that is likely to benefit from corticosteroid treatment.

The Role of Exhaled Nitric Oxide in Evaluation of Acute Asthma in a Pediatric Emergency Department

Fractional excretion of nitric oxide (FE(NO)) has been used as a noninvasive marker to assess and manage chronic asthma in adults and children. The aim of this study was to determine the feasibility of obtaining FE(NO) concentrations in children treated in the emergency department (ED) for acute asthma exacerbation and to examine the association between FE(NO) concentrations and other measures of acute asthma severity. This was a cross-sectional study of a convenience sample of children 2-18 years old who were seen in an urban ED for acute asthma exacerbation. Using a tidal breathing method with real-time display, the authors measured FE(NO) concentrations before and 1 hour after the administration of corticosteroids and at discharge from the ED. Outcome measures included pulmonary index score (PIS), hospital admission, and short-term outcomes (e.g., missed days of school). A total of 133 subjects were enrolled. Sixty-eight percent (95% confidence interval [CI] = 60% to 76%) of the subjects provided adequate breaths for FE(NO) measurement. There was no difference in the median initial FE(NO) concentration among subjects, regardless of the severity of their acute asthma. Most subjects showed no change in their FE(NO) concentrations from the start to the end of treatment. FE(NO) concentrations were not significantly associated with other short-term outcomes. Measurement of FE(NO) is difficult for a large proportion of children with acute asthma exacerbation. FE(NO) concentration during an asthma exacerbation does not correlate with other measures of acute severity and has limited utility in the ED management of acute asthma in children.

Exhaled Nitric Oxide Measurement Is Useful for the Exclusion of Nonasthmatic Eosinophilic Bronchitis in Patients With Chronic Cough

Nonasthmatic eosinophilic bronchitis (NAEB) is an important cause of chronic cough, and it can be diagnosed by an induced-sputum (IS) examination. However, an IS examination is a complex and time-consuming procedure, and it has limited clinical application. This study aimed to evaluate the role of exhaled nitric oxide (NO) for the investigation of chronic cough, especially of NAEB. Two hundred eleven nonsmoking patients with a cough lasting > 3 weeks were enrolled in the study. The patients were examined and investigated with conventional diagnostic tools, including an IS examination. Exhaled NO was measured by a chemoluminescent analyzer. One hundred seventeen patients with adequate IS results were analyzed: asthma, n = 14; NAEB, n = 21; and "others," n = 82. Exhaled NO and IS eosinophils were significantly higher in the asthma group and NAEB group than in the others group. Exhaled NO and IS eosinophils were significantly correlated in the asthma and NAEB groups. In the nonasthmatic group, the sensitivity and specificity of exhaled NO for detecting NAEB, using 31.7 parts per billion as the exhaled NO cutoff point, were 86% and 76%, respectively. Positive and negative predictive values were 47% and 95%, respectively, and positive and negative likelihood ratios were 3.51 and 0.19, respectively. We concluded that exhaled NO measurement may be useful as part of the initial evaluation for chronic cough, especially for the exclusion of NAEB. A low level of exhaled NO suggested little likelihood of NAEB for the nonasthmatic patients with chronic cough.

Management of asthma based on exhaled nitric oxide in addition to guideline-based treatment for inner-city adolescents and young adults: a randomised controlled trial

Preliminary evidence is equivocal about the role of exhaled nitric oxide (NO) in clinical asthma management. We aimed to assess whether measurement of exhaled NO, as a biomarker of airway inflammation, could increase the effectiveness of asthma treatment, when used as an adjunct to clinical care based on asthma guidelines for inner-city adolescents and young adults. We did a randomised, double-blind, parallel-group trial at ten centres in the USA. We screened 780 inner-city patients, aged 12-20 years, who had persistent asthma. All patients completed a run-in period of 3 weeks on a regimen based on standard treatment. 546 eligible participants who adhered to treatment during this run-in period were then randomly assigned to 46 weeks of either standard treatment, based on the guidelines of the National Asthma Education and Prevention Program (NAEPP), or standard treatment modified on the basis of measurements of fraction of exhaled NO. The primary outcome was the number of days with asthma symptoms. We analysed patients on an intention-to-treat basis. This trial is registered with clinicaltrials.gov, number NCT00114413. During the 46-week treatment period, the mean number of days with asthma symptoms did not differ between the treatment groups (1.93 [95% CI 1.74 to 2.11] in the NO monitoring group vs 1.89 [1.71 to 2.07] in the control group; difference 0.04 [-0.22 to 0.29], p=0.780). Other symptoms, pulmonary function, and asthma exacerbations did not differ between groups. Patients in the NO monitoring group received higher doses of inhaled corticosteroids (difference 119 mug per day, 95% CI 49 to 189, p=0.001) than controls. Adverse events did not differ between treatment groups (p>0.1 for all adverse events). Conventional asthma management resulted in good control of symptoms in most participants. The addition of fraction of exhaled NO as an indicator of control of asthma resulted in higher doses of inhaled corticosteroids, without clinically important improvements in symptomatic asthma control.

The role of exhaled nitric oxide and exhaled breath condensates in evaluating airway inflammation in asthma

Airway inflammation is central to the development and progression of asthma. Monitoring airway inflammation can be invasive and technically difficult, making its use limited in clinical practice. Several advances have been made in non-invasive techniques to monitor and measure inflammation from the airways. To examine the suitability of exhaled nitric oxide and exhaled breath condensates as diagnostic tools in asthma. The current literature regarding the use of exhaled nitric oxide and exhaled breath condensate to assess and manage asthma was reviewed. Exhaled nitric oxide is a clinically useful marker of eosinophilic airway inflammation in asthma. Although showing promise, significant validation and investigation are required before exhaled breath condensate could be utilized in clinical practice.

Medição do óxido nítrico no ar exalado: Utilização na avaliação de crianças com história de sibilância

The body of published work on the role of exhaled nitric oxide (FENO) in the study of bronchial inflammation allows it to be classed as a simple, non-invasive measurement that is very useful in evaluating asthmatic patients.During a prospective study into the effects of air pollution on the health of the population of Viseu (Saud'AR Project), children with a clinical history of wheezing were identified through using the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire. Children later filled in a new standardised questionnaire and underwent skin-prick-tests, spirometry and FENO measurement. Their mean age was 7.8±1.1 years. Comparing those who wheezed in the 6 months before evaluation (n=27) with those who didn’t, statistical differences for ΔFEV1 (8% median versus 4.5%, p=0.0399) and for FENO (23 ppb median versus 12 ppb, p=0.0195, respectively) were observed. Concerning children who needed a bronchodilator in the six previous months (n=19) and those who didn’t, there was also a statistically significant difference in FENO: 27 ppb median versus 11 ppb median, respectively; p<0.0001. When comparing children who needed an unscheduled medical appointment in the six months previous to the evaluation (n=9) and those who didn’t, there was also significant differences for FENO: 28 ppb median versus 13 ppb median, p=0.0029. In conclusion, the existence of symptoms seems to be better related to FENO than spirometry.Rev Port Pneumol 2007; XIV (2): 195-218

The clinical use of exhaled nitric oxide in wheezing children

The body of published work on the role of exhaled nitric oxide (FENO) in the study of bronchial inflammation allows it to be classed as a simple, non-invasive measurement that is very useful in evaluating asthmatic patients.During a prospective study into the effects of air pollution on the health of the population of Viseu (Saud’AR Project), children with a clinical history of wheezing were identified through using the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire. Children later filled in a new standardised questionnaire and underwent skin-prick-tests, spirometry and FENO measurement. Their mean age was 7.8±1.1 years. Comparing those who wheezed in the 6 months before evaluation (n=27) with those who didn’t, statistical differences for ΔFEV1 (8% median versus 4.5%, p=0.0399) and for FENO (23 ppb median versus 12 ppb, p=0.0195, respectively) were observed. Concerning children who needed a bronchodilator in the six previous months (n=19) and those who didn’t, there was also a statistically significant difference in FENO: 27 ppb median versus 11 ppb median, respectively; p<0.0001. When comparing children who needed an unscheduled medical appointment in the six months previous to the evaluation (n=9) and those who didn’t, there was also significant differences for FENO: 28 ppb median versus 13 ppb median, p=0.0029. In conclusion, the existence of symptoms seems to be better related to FENO than spirometry.