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Exhaled NO (exhaled + no)
Selected AbstractsExhaled NO in asthma: still in touch or definitively out of bounds?ALLERGY, Issue 3 2010B. Degano No abstract is available for this article. [source] Alveolar and bronchial nitric oxide output in healthy childrenPEDIATRIC PULMONOLOGY, Issue 12 2008Anna Sepponen MD Abstract Exhaled nitric oxide (NO) concentration is a marker of pulmonary inflammation. It is usually measured at a single exhalation flow rate. However, measuring exhaled NO at multiple flow rates allows assessment of the flow-independent NO parameters: alveolar NO concentration, bronchial NO flux, bronchial wall NO concentration, and bronchial diffusing capacity of NO. Our aim was to determine the flow-independent NO parameters in healthy schoolchildren and to compare two different mathematical approaches. Exhaled NO was measured at four flow rates (10, 50, 100, and 200 ml/sec) in 253 schoolchildren (7,13 years old). Flow-independent NO parameters were calculated with linear method (flows ,50 ml/sec) and non-linear method (all flows). Sixty-six children (32 boys and 34 girls) with normal spirometry and no history or present symptoms of asthma, allergy, atopy or other diseases were included in the analysis. Median bronchial NO flux was 0.4 nl/sec (mean,±,SD: 0.5,±,0.3 nl/sec) and median alveolar NO concentration was 1.9 ppb (2.0,±,0.8 ppb) with the linear method. Bronchial NO flux correlated positively with height (r,=,0.423; P,<,0.001), FEV1 (r,=,0.358; P,=,0.003), and FVC (r,=,0.359; P,=,0.003). With the non-linear method, median bronchial wall NO concentration was 49.6 ppb (68.0,±,53.3 ppb) and bronchial diffusing capacity of NO was 10.0 pl/sec/ppb (11.8,±,7.5 pl/sec/ppb). The non-linear method gave lower alveolar NO concentration (1.4 [1.5,±,0.7] ppb, P,<,0.001) and higher bronchial NO flux (0.5 [0.6,±,0.3] nl/sec, P,<,0.001) than the linear method, but the results were highly correlated between the two methods (r,=,0.854 and r,=,0.971, P,<,0.001). In conclusion, the multiple flow rate method is feasible in children but different mathematical methods give slightly different results. Reference values in healthy children are of value when applying bronchial and alveolar NO parameters in the diagnostics and follow-up of inflammatory lung diseases. Pediatr. Pulmonol. 2008; 43:1242,1248. © 2008 Wiley-Liss, Inc. [source] Methodological issues related to exhaled nitric oxide measurement in children aged four to six yearsPEDIATRIC PULMONOLOGY, Issue 2 2005Edward Napier MBBS Abstract This study was designed to test five methodological issues related to measurement of fractional exhaled nitric oxide (FENO) in children aged 4,6 years using commercially available apparatus. Participants attended two randomly selected schools. A respiratory questionnaire was completed. Measurements of FENO were made on successive days, using a NIOX® analyzer employing standard or modified methodologies. Ninety-one children participated in the study (mean age, 5.3 years; 46 boys). Using a standard methodology (n,=,61), FENO was successfully measured in 28 (46%) children, 1/12 aged 4 years, 12/25 aged 5 years, and 15/24 aged 6 years (trend test P,=,0.01). On the first assessment, FENO could be determined in more boys than girls (64% vs. 30%, respectively, P,=,0.008), but this gender difference was not apparent on the second assessment. Exhaled NO was reproducible over a 24-hr period; the mean difference between repeated measurements of natural log (ln) FENO was 0.016 parts per billion (ppb) (95% confidence limits, ,0.479, 0.511), n,=,20. Data from 35 assessments showed that values of FENO did not alter over nine individual, successive measurements. Use of a modified methodology in 30 children increased success in obtaining FENO, but these values were unreliable. In conclusion, measurements of FENO can be obtained in the majority of 5- and 6-year-old but not 4-year-old children. Exhaled NO measurements were reproducible over a 24-hr interval, and did not change over up to nine expiratory maneuvers in these young children. Pediatr Pulmonol. 2005; 40:97,104. © 2005 Wiley-Liss, Inc. [source] Childhood asthma: Exhaled markers of airway inflammation, asthma control score, and lung function testsPEDIATRIC PULMONOLOGY, Issue 2 2004Philippe P.R. Rosias MD Abstract Exhaled markers of airway inflammation become increasingly important in the management of childhood asthma. The aims of the present study are: 1) to compare exhaled markers of inflammation (nitric oxide, carbon monoxide, and acidity of breath condensate) with conventional asthma measures (lung function tests and asthma control score) in childhood asthma; and 2) to investigate the detectability of albumin, CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in the exhaled breath condensate (EBC) of asthmatic children. Thirty-two children with mild to moderate persistent asthma and healthy controls aged 6,12 years were studied. We measured exhaled NO and CO, and subsequently EBC was collected. Inflammatory mediators in EBC were measured using an enzyme-linked immunosorbent assay. Respiratory symptoms and asthma control were assessed using the asthma control questionnaire (ACQ) of Juniper et al. (Eur Respir J 1999;14:902,907). Exhaled NO showed a significant correlation with exhaled CO (r,=,0.59, P,<,0.05) and FEV1 (r,=,,0.59, P,<,0.05), but not with ACQ score (r,=,0.48, P,=,0.06). Exhaled CO was correlated with prebronchodilator FEV1 (r,=,,0.45, P,<,0.05), but not with asthma control (r,=,0.18, P,=,0.35). Acidity of EBC was significantly lower in asthmatic children than in healthy controls (P,<,0.05), but did not correlate with any of the conventional asthma measures. We were not able to demonstrate the presence of CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in EBC. Albumin was found in two EBC samples of asthmatic children. We conclude that exhaled NO had a better correlation with lung function parameters and asthma control than exhaled CO and acidity of EBC, in mild to moderate persistent childhood asthma. However, exhaled NO, CO, and deaerated pH of EBC did not differ between asthmatic children and controls, possibly because of a too homogeneous and well-controlled study population. To further evaluate the clinical utility of exhaled markers in monitoring childhood asthma, more studies are required on a wider range of asthma severity, and preferably with repeated measurements of markers and of asthma control. Pediatr Pulmonol. 2004; 38:107,114. © 2004 Wiley-Liss, Inc. [source] Single-breath exhaled nitric oxide in preschool children facilitated by a servo-controlled device maintaining constant flow,PEDIATRIC PULMONOLOGY, Issue 6 2004Philip E. Silkoff MD Abstract Fractional concentration of exhaled nitric oxide (FENO), an index of airway inflammation, is optimally measured in adults and school-age children using a single-breath online (SBOL) exhalation at constant flow. However, preschool-aged (<6 years old) children have difficulty exhaling at constant flow, and alternative methods are needed. We employed a servo-controlled variable resistance device (servo device) that controls expiratory flow while allowing the child to vary expiratory pressure. To validate this device, 8 children (aged 6,12 years) performed SBOL exhalations with and without the servo device at expired flow rates between 20,50 ml/sec. We then studied 32 young children aged 24,71 months with the servo device alone at exhalation flows of 30, 40, and 50 ml/sec. Test difficulty (TD) with each method was rated by questioning the older children, or as observed by the physician obtaining the data in the younger children (0,=,no difficulty, 1,=,mild difficulty, 2,=,moderate difficulty, and 3,=,unable to perform test). In the older children, SBOL exhalations with and without the servo device demonstrated equivalent flow-dependence of FENO values. Test difficulty was low (0.125,0.625) at all flow rates, with excellent agreement between the two methods (P,<,0.001). Twenty-eight young children (<6 years old) were able to complete measurements at all three flow rates evaluated. The 4 subjects who were not able to successfully complete all the measurements were between 2,3 years old (mean 2.75,±,SD). Exhaled NO (mean,±,SD; ppb) was 8.8 (±6.2), 10.6 (±6.7), and 13.2 (±8.8) ppb at flows of 50 ml/sec, 40 ml/sec, and 30 ml/sec, respectively. Mean values of SD scores were 1.00, 1.14, and 1.43 at flows of 50, 40, and 30 ml/sec, respectively (P,=,NS). In conclusion, exhaled NO measurement by the SBOL method was facilitated in preschool children by the use of a servo-controlled variable resistance device. This device may allow these measurements to be applied to aid in the diagnosis and treatment of asthma in the preschool child, where spirometry is generally impossible. Pediatr Pulmonol. 2004; 37:554,558. © 2004 Wiley-Liss, Inc. [source] Exhaled nitric oxide in seasonal allergic rhinitis: influence of pollen season and therapyCLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2001C. Gratziou Exhaled nitric oxide (eNO) has been proposed as a potential indirect marker of lower airway inflammation in asthma. To investigate the existence of lower airways inflammation in allergic rhinitis eNO measurements were performed in 32 patients with symptomatic and asymptomatic seasonal allergic rhinitis early in and out of pollen seasons and in 80 healthy volunteers. To further define how exhaled NO is modified by therapy, NO levels were detected following 1-month treatment with either inhaled steroids or non-steroids therapy with nedocromil. Exhaled NO (mean ±,SE) was significantly elevated in patients with seasonal allergic rhinitis with and without symptoms (24.2 + 2.5 and 13.9 + 2.9 ppb, respectively) as compared to healthy volunteers (4.5 + 0.3 ppb) both in and out of pollen season (21.2 + 2.1 and 9.0 + 1.4 p.p.b., respectively) with a higher increase during the allergen exposure in season. Higher levels of exhaled NO were detected in patients with symptoms, either from the upper or lower airways, and with bronchial hyperreactivity. The increased exhaled NO in symptomatic patients was reduced only by inhaled steroids and not by nedocromil. These findings possibly suggest the existence of lower airway inflammation in both symptomatic and asymptomatic patients with seasonal allergic rhinitis in and out of pollen season. Thus, exhaled NO may be used as a non-invasive index for early detection of lower airway inflammation and for monitoring the optional treatment in patients with seasonal allergic rhinitis. [source] The Lung Is The Major Site That Produces Nitric Oxide To Induce Acute Pulmonary Oedema In Endotoxin ShockCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2001Ru Ping Lee SUMMARY 1. The present study was undertaken to determine the locus of nitric oxide (NO) production that is toxic to the lung and produces acute pulmonary oedema in endotoxin shock, to examine and compare the effects of changes in lung perfusate on endotoxin-induced pulmonary oedema (EPE) and to evaluate the involvement of constitutive and inducible NO synthase (cNOS and iNOS, respectively). 2. Experiments were designed to induce septic shock in anaesthetized rats with the administration of Escherichia coli lipopolysaccharide (LPS). Exhaled NO, lung weight (LW)/bodyweight (BW) ratio, LW gain (LWG) and lung histology were measured and observed to determine the degree of EPE 4 h following LPS. The EPE was compared between groups in which LPS had been injected either into the systemic circulation or into the isolated perfused lung. The lung perfusate was altered from whole blood to physiological saline solution (PSS) with 6% albumin to test whether different lung perfusions affected EPE. Pretreatment with various NOS inhibitors was undertaken 10 min before LPS to investigate the contribution of cNOS and iNOS to the observed effects. 3. Endotoxin caused profound systemic hypotension, but little change in pulmonary arterial pressure. The extent of EPE was not different between that induced by systemic injection and that following administration to isolated lungs preparations. Replacement of whole blood with PSS greatly attenuated (P < 0.05) EPE. In blood-perfused lungs, pretreatment with NOS inhibitors, such as N, -nitro- L -arginine methyl ester, aminoguanidine and dexamethasone, significantly prevented EPE (P < 0.05). 4. The major site of NO production through the whole blood is in the lung. The NO production mediated by the iNOS system is toxic to the endothelium in the pulmonary microvasculature. Inhalation of NO for patients with sepsis may be used with clinical caution. Therapeutic consideration of lung extracorporeal perfusion with PSS and pharmacological pretreatment with iNOS inhibitors may be warranted. [source] Nerve growth factor increases airway responses and decreases levels of exhaled nitric oxide during histamine challenge in an in vivo guinea-pig modelACTA PHYSIOLOGICA, Issue 2 2001S. G. Friberg There is a growing body of evidence supporting the idea that nerve growth factor (NGF) may be involved in the development of asthma-associated symptoms, such as airway hyper-responsiveness. Increased levels of NGF have recently been described in serum and in the airways of asthmatics. We have examined whether exhaled nitric oxide (NO) levels might be altered during the increased airway responses upon NGF treatment in guinea-pigs in vivo. Intravenous (i.v.) administration of histamine normally elicits a rapid peak in insufflation pressure (IP) and in exhaled NO, followed by a period of decreased concentrations of exhaled NO. Anaesthetized guinea-pigs were pre-treated intravenously with either saline, 4 or 80 ng kg,1 NGF 30 min before i.v. challenge with 16 ,g kg,1 histamine. At 80 ng kg,1 NGF significantly enhanced the airway obstruction caused by histamine, whereas the peak acute increase in exhaled NO was not enhanced. Following the increase, came a rapid drop, an effect enforced in the NGF treated animals. Subsequently, the time to return to 90% of resting exhaled NO was increased, from 12 min in saline-treated animals to 48 min in NGF-treated animals. Our data confirm that NGF can enhance airway responses to histamine. Moreover, our study shows a decrease in exhaled NO following a histamine challenge, an effect enhanced by NGF. A reduced ability to release exhaled NO may be a mechanism for increased airway responses during elevated NGF levels. The interaction between NGF and airway NO formation, and its relation to airway responses, merit further investigation. [source] Effect of montelukast on exhaled NO in asthmatic children exposed to relevant allergensPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 2 2002Giorgio L. Piacentini 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 (t0) and immediately after (t1) 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 t0 and t1, 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. [source] Childhood asthma: Exhaled markers of airway inflammation, asthma control score, and lung function testsPEDIATRIC PULMONOLOGY, Issue 2 2004Philippe P.R. Rosias MD Abstract Exhaled markers of airway inflammation become increasingly important in the management of childhood asthma. The aims of the present study are: 1) to compare exhaled markers of inflammation (nitric oxide, carbon monoxide, and acidity of breath condensate) with conventional asthma measures (lung function tests and asthma control score) in childhood asthma; and 2) to investigate the detectability of albumin, CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in the exhaled breath condensate (EBC) of asthmatic children. Thirty-two children with mild to moderate persistent asthma and healthy controls aged 6,12 years were studied. We measured exhaled NO and CO, and subsequently EBC was collected. Inflammatory mediators in EBC were measured using an enzyme-linked immunosorbent assay. Respiratory symptoms and asthma control were assessed using the asthma control questionnaire (ACQ) of Juniper et al. (Eur Respir J 1999;14:902,907). Exhaled NO showed a significant correlation with exhaled CO (r,=,0.59, P,<,0.05) and FEV1 (r,=,,0.59, P,<,0.05), but not with ACQ score (r,=,0.48, P,=,0.06). Exhaled CO was correlated with prebronchodilator FEV1 (r,=,,0.45, P,<,0.05), but not with asthma control (r,=,0.18, P,=,0.35). Acidity of EBC was significantly lower in asthmatic children than in healthy controls (P,<,0.05), but did not correlate with any of the conventional asthma measures. We were not able to demonstrate the presence of CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in EBC. Albumin was found in two EBC samples of asthmatic children. We conclude that exhaled NO had a better correlation with lung function parameters and asthma control than exhaled CO and acidity of EBC, in mild to moderate persistent childhood asthma. However, exhaled NO, CO, and deaerated pH of EBC did not differ between asthmatic children and controls, possibly because of a too homogeneous and well-controlled study population. To further evaluate the clinical utility of exhaled markers in monitoring childhood asthma, more studies are required on a wider range of asthma severity, and preferably with repeated measurements of markers and of asthma control. Pediatr Pulmonol. 2004; 38:107,114. © 2004 Wiley-Liss, Inc. [source] Inflammatory and oxidative stress biomarkers in allergic rhinitis: the effect of smokingCLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2009K. Tanou Summary Background Accumulating evidence confirms the presence of pan-airway inflammation in allergic rhinitis patients. Smoking is known to affect the asthmatic airway inflammation. However, no study has evaluated the impact of smoking on airway inflammation of allergic rhinitis patients. Objective The aim of the present study was to evaluate the impact of smoking on inflammatory and oxidative stress biomarkers in patients with seasonal allergic rhinitis, using non-invasive methods for sample collection. Methods Forty patients with seasonal allergic rhinitis (20 smokers and 20 non-smokers) and 30 healthy subjects (15 smokers and 15 non-smokers) were recruited for the study during pollen season. All subjects were submitted to measurement of the fraction of exhaled NO (FeNO), exhaled breath condensate (EBC) collection, nasal lavage collection, pre- and post- bronchodilation spirometry and metacholine bronchial challenge testing. pH, leukotriene B4 (LTB4) and 8-isoprostane were determined in EBC and nasal lavage samples. Results Patients with allergic rhinitis presented higher LTB4 and 8-isoprostane levels in nasal lavage (P<0.0001 for both comparisons), with no significant differences between smokers and non-smokers. Patients with allergic rhinitis also presented higher LTB4 levels and lower pH in EBC (P<0.001 and P=0.004, respectively), with prominent differences between smokers and non-smokers (P<0.0001 and P=0.003, for LTB4 and pH, respectively). A significant correlation between nasal lavage and EBC LTB4 values was observed (rs=0.313, P=0.048). Conclusions Patients with allergic rhinitis present increased LTB4 and 8-isoprostane in their nasal cavity, however, with no significant differences between smokers and non-smokers. In contrast, smokers with allergic rhinitis present higher LTB4 levels and lower pH in EBC, suggesting that these patients may be more susceptible to the deleterious effects of smoking, compared with non-smokers. [source] Nitric oxide evaluation in upper and lower respiratory tracts in nasal polyposisCLINICAL & EXPERIMENTAL ALLERGY, Issue 7 2008C. Delclaux Summary Background A decrease in nasal nitric oxide (NO) and an increase in exhaled NO have been demonstrated in patients with nasal polyposis (NP). Objectives The aims were to evaluate the flux of NO from the three compartments of the respiratory tract, namely, upper nasal, lower conducting and distal airways, and to search for relationships between NO parameters and indexes of upper and lower disease activity (bronchial reactivity and obstruction). The effect of medical treatment of polyposis was also evaluated. Methods Seventy patients with polyposis were recruited. At baseline, pulmonary function tests (spirometry, plethysmography, bronchomotor response to deep inspiration using forced oscillation measurement of resistance of respiratory system, methacholine challenge, multiple flow rates of exhaled NO and nasal NO measurements) were performed together with an assessment of polyposis [clinical, endoscopic and computed tomography (CT) scores]. Results Statistical relationships were demonstrated between nasal NO flux and severity scores (clinical: ,=,0.31, P=0.015; endoscopic: ,=,0.57, P<0.0001; CT: ,=,0.46, P=0.0005), and between alveolar NO concentration and distal airflow limitation (FEF25,75, ,=,0.32, P=0.011). Thirty-six patients were assessed after 11 [7,13] (median [interquartile]) months of medical treatment, demonstrating an improvement in clinical and endoscopic scores, an increase in nasal NO flux, a decrease in NO flux from conducting airways, an improvement in the mild airflow limitation (forced expiratory volume in 1 s, FEF25,75, even in non-asthmatic patients) and a decrease in the bronchoconstrictor effect of deep inspiration. Conclusions The medical treatment of NP improves both airway reactivity and obstruction, whatever the presence of asthma, suggesting a functional link between upper and lower airway functions. [source] Exhaled nitric oxide: relation to sensitization and respiratory symptomsCLINICAL & EXPERIMENTAL ALLERGY, Issue 2 2004A.-C. Olin Summary Background Conflicting data have been presented as to whether nitric oxide (NO) in exhaled air is merely reflecting atopy rather than airway inflammation. Objective To investigate the relationship between exhaled NO (eNO) and nasal NO (nNO), respiratory symptoms, and atopy, in the context of a cross-sectional study of the respiratory health of bleachery workers. Methods Two hundred and forty-six non-smoking bleachery and paper-mill workers answered a questionnaire and were examined by measurements of eNO and nNO and spirometry, outside the pollen season. Blood samples were collected and analysed for specific IgE against common aeroallergens (birch, timothy, cat and house dust mite). Atopy was defined as a positive PhadiatopÔ test. Results The atopic and the non-atopic subjects without asthma or rhinitis had similar levels of eNO. Subjects reporting asthma or rhinitis who were also sensitized to perennial allergens had higher levels of eNO, whereas those sensitized to only seasonal allergens had similar eNO levels as non-atopic subjects with asthma or rhinitis. In multiple linear regression models adjusted for nNO, eNO was associated with asthma and sensitization to perennial allergens. Conclusion The results indicate that only atopic subjects who have recently been exposed to the relevant allergen have elevated levels of eNO. Atopic subjects who are not being exposed to a relevant allergen or have never experienced symptoms of asthma or rhinitis show normal eNO. These data indicate that eNO relates to airway inflammation in atopic subjects. [source] Effect of montelukast pretreatment on inducible nitric oxide synthase mRNA expression in the lungs of antigen-challenged allergic miceCLINICAL & EXPERIMENTAL ALLERGY, Issue 12 2003K. Sade Summary Background Growing evidence suggests that inducible nitric oxide synthase (iNOS) is the main source of the high output of exhaled nitric oxide (NO) in asthma. Treatment of asthmatic patients with glucocorticoids reduces high levels of exhaled NO mainly by inhibiting the transcription of iNOS. A similar reduction in exhaled NO was recently observed in patients treated with the leukotriene receptor antagonists, but the exact interaction between these drugs and iNOS remains obscure. Objective The purpose of this study was to evaluate the effect of a leukotriene receptor antagonist, montelukast, on the expression and activity of iNOS in a murine model of allergic asthma. Methods Twenty-four BALB/c mice were sensitized to OVA and were equally divided into 3 groups (Groups 1,3). Eight additional mice were sham sensitized and served as a negative control group (Group 4). Group 1 received montelukast 1 mg/kg/day in their drinking water, Group 2 received dexamethasone 1 mg/kg/day in their drinking water and Groups 3 and 4 received plain tap water. After 1 week, the animals were challenged by inhalation of OVA and, 3 h later, they were killed and their lung cells were isolated by enzymatic tissue digestion. NO generation was measured by a Griess assay, and iNOS mRNA was studied by RT-PCR. Results A significant increase in iNOS mRNA expression and in NO generation was evident after allergen challenge compared with the controls. Pretreatment with montelukast mildly decreased NO production without producing a concomitant significant decrease in iNOS mRNA expression. Conclusion: Unlike pretreatment with glucocorticoids, we failed to find compelling evidence for a major role for montelukast treatment in the modulation of iNOS mRNA in a murine model of acute asthma. [source] Exhaled nitric oxide in seasonal allergic rhinitis: influence of pollen season and therapyCLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2001C. Gratziou Exhaled nitric oxide (eNO) has been proposed as a potential indirect marker of lower airway inflammation in asthma. To investigate the existence of lower airways inflammation in allergic rhinitis eNO measurements were performed in 32 patients with symptomatic and asymptomatic seasonal allergic rhinitis early in and out of pollen seasons and in 80 healthy volunteers. To further define how exhaled NO is modified by therapy, NO levels were detected following 1-month treatment with either inhaled steroids or non-steroids therapy with nedocromil. Exhaled NO (mean ±,SE) was significantly elevated in patients with seasonal allergic rhinitis with and without symptoms (24.2 + 2.5 and 13.9 + 2.9 ppb, respectively) as compared to healthy volunteers (4.5 + 0.3 ppb) both in and out of pollen season (21.2 + 2.1 and 9.0 + 1.4 p.p.b., respectively) with a higher increase during the allergen exposure in season. Higher levels of exhaled NO were detected in patients with symptoms, either from the upper or lower airways, and with bronchial hyperreactivity. The increased exhaled NO in symptomatic patients was reduced only by inhaled steroids and not by nedocromil. These findings possibly suggest the existence of lower airway inflammation in both symptomatic and asymptomatic patients with seasonal allergic rhinitis in and out of pollen season. Thus, exhaled NO may be used as a non-invasive index for early detection of lower airway inflammation and for monitoring the optional treatment in patients with seasonal allergic rhinitis. [source] Exhaled and nasal nitric oxide in mechanically ventilated preterm and term newbornsACTA PAEDIATRICA, Issue 10 2002O Aikio Aim: Nitric oxide (NO) is an important mediator required for neonatal pulmonary circulatory adaptation and for pulmonary defence. Both deficient and excessive NO production have been proposed to play a role in neonatal lung disease. This study aimed to establish a method that allows direct measurement of exhaled and nasal NO concentrations in newborn infants who require intubation and ventilation. Methods: A rapid-response chemiluminescence NO analyser was used. Gas was sampled from the endotracheal intubation tube, and tidal volumes and flow rates were measured. The nasal NO was sampled from the non-intubated nostril. The accuracy of the method was validated using a lung model. NO levels from six preterm and six term/near-term newborns were studied. Measurements were performed on a daily basis during the first week. Results: An expiration >0.2 s in duration with a flow rate >1.7mls,1 could be accurately analysed for the presence of >1 parts per billion of NO. The very preterm infants with neonatal lung disease had a different postnatal NO output pattern from the lower and upper airways compared with the ventilated term/near-term infants. Conclusion: A novel method for measurement of exhaled NO of an intubated newborn is presented. The possible association of exhaled NO concentration with the development of chronic lung disease remains to be studied. [source] |