Inflammatory patterns in asthmatic children based on alveolar nitric oxide determination.

INTRODUCTION: Nitric oxide (NO) levels can be measured at proximal (maximum airway NO flux [J'aw(NO)]) and distal (alveolar NO concentration [C(ANO)]) levels. Four inflammatory patterns have been described in asthmatic individuals, although their relevance has not been well established. The objective was to determine J'aw(NO) and C(ANO) in order to establish four inflammatory categories in asthmatics. MATERIAL AND METHODS: Cross-sectional study of a sample consisting of healthy and asthmatic children. Exhaled NO was determined at multiple flows. J'aw(NO) and C(ANO) were obtained according to the two-compartment model. The asthma control questionnaire (ACQ) and spirometry were administered to asthmatic children. Patients were categorized as type I (normal J'aw(NO) and C(ANO)), type II (elevated J'aw(NO) and normal C(ANO)), type III (elevated J'aw(NO) and C(ANO)) and type IV (normal J'aw(NO) and elevated C(ANO)). Correlation between FE(NO,50), J'aw(NO) and C(ANO) was analyzed using Spearman's R Correlation Test. Analysis of variance and paired comparisons were performed using the Bonferroni correction. RESULTS: One hundred sixty-two children were studied, of whom 49 (32.23%) were healthy controls and 103 (67.76%) asthmatics. In the control subjects, FE(NO,50) (ppb)(median and range) was 11.5 (1.6 to 27.3), J'aw(NO) (pl/s) was 516 (98.3 to 1470) and C(ANO) (ppb) was 2.2 (0.1 to 4.5). Forty-four (42.7%) of the asthmatic participants were categorized as type I, 41 (39.8%) as type II, 14 (13.5%) as type III and 4 (3.88%) as type IV. Good correlation was observed between J'aw(NO) and FE(NO,50) (r=0.97). There was no association between J'aw(NO) and C(ANO). FEV1/FVC decreased significantly in type III (mean 79.8±7.5). Morbidity was significantly higher in types III and IV. CONCLUSIONS: Normal values obtained are similar to those previously reported. Asthmatics with high C(ANO) showed higher morbidity. No correlation was found between proximal and distal inflammation.

Patrones inflamatorios en niños asmáticos basados en la determinación de óxido nítrico alveolar / Inflammatory Patterns in Asthmatic Children Based on Alveolar Nitric Oxide Determination

Introducción: El óxido nítrico (NO) puede medirse a nivel proximal (flujo máximo NO en vía aérea [J'awNO]) y distal (concentración alveolar de NO [CANO]). Se han descrito 4 patrones inflamatorios en asmáticos, aunque su relevancia no ha sido bien establecida. El objetivo ha sido determinar el J'awNO y la CANO para establecer 4 categorías inflamatorias en asmáticos. Material y métodos: Estudio transversal de una muestra de niños sanos y asmáticos. Determinación de NO exhalado a flujos múltiples. De acuerdo con el modelo bicompartimental se obtuvieron la CANOy el J'awNO. En asmáticos se realizó cuestionario de control de asma (CAN) y espirometría forzada. Categorización de pacientes en tipo i (J'awNO y CANO normal), tipo ii (J'awNO elevado y CANO normal), tipo iii (J'awNO y CANO elevados) y tipo iv (J'awNO normal y CANO elevado). Estudio de correlación entre FENO,50, J'awNO y CANO mediante R de Spearman. Análisis de la varianza y comparaciones pareadas, mediante corrección post hoc de Bonferroni. Resultados: Se estudiaron 162 niños: 49 (32,23%) controles sanos y 103 (67,76%) asmáticos. Se excluyeron 10 niños, 4 (2.4%) porque las eterminaciones fueron incorrectas y 6 (3,7%) porque las determinaciones no siguieron el modelo lineal (valores de CANO negativos). En controles la FENO,50 (ppb) (mediana y rango) fue 11,5 (1,6-27,3), J'awNO (pl/s) 516 (98,3-1.470) y CANO(ppb) 2,2 (0,1-4,5). De los asmáticos, 44 (42,7%) se categorizaron en tipo i, 41 (39,8%) en tipo ii, 14 (13,5%%) en tipo iii y 4 (3,88%) en tipo iv. Buena correlación entre J'awNO y FENO,50(r = 0,97). No hubo asociación entre J'awNO y CANO. Disminución significativa de FEV1/FVC en tipo iii (media 79,8 ± 7,5). La morbilidad fue significativamente superior en tipos iii y iv. Conclusiones: Los valores de normalidad obtenidos son similares a los previamente publicados. Los asmáticos con CANO elevado presentaron mayor morbilidad. No hay correlación entre inflamación proximal y distal

Introduction: Nitric oxide (NO) levels can be measured at proximal (maximum airway NO flux [J’awNO]) and distal (alveolar NO concentration [CANO]) levels. Four inflammatory patterns have been described in asthmatic individuals, although their relevance has not been well established. The objective was to determine J’awNO and CANO in order to establish four inflammatory categories in asthmatics. Material and methods: Cross-sectional study of a sample consisting of healthy and asthmatic children. Exhaled NO was determined at multiple flows. J’awNO and CANO were obtained according to the two-compartment model. The asthma control questionnaire (ACQ) and spirometry were administered to asthmatic children. Patients were categorized as type i (normal J’awNO and CANO), type ii (elevated J’awNO and normal CANO), type iii (elevated J’awNO and CANO) and type iv (normal J’awNO and elevated CANO). Correlation between FENO,50, J’awNO and CANO was analyzed using Spearman’s R Correlation Test. Analysis of variance and paired comparisons were performed using the Bonferroni correction. Results: One hundred sixty-two children were studied, of whom 49 (32.23%) were healthy controls and 103 (67.76%) asthmatics. In the control subjects, FENO,50 (ppb)(median and range) was 11.5 (1.6 to 27.3), J’awNO (pl/s) was 516 (98.3 to 1470) and CANO (ppb) was 2.2 (0.1 to 4.5). Forty-four (42.7%) of the asthmatic participants were categorized as type i, 41 (39.8%) as type ii, 14 (13.5%) as type iii and 4 (3.88%) as type iv. Good correlation was observed between J’awNO and FENO,50 (r = 0.97). There was no association between J’awNO and CANO. FEV1/FVC decreased significantly in type iii (mean 79.8 ± 7.5). Morbidity was significantly higher in types iii and iv. Conclusions: Normal values obtained are similar to those previously reported. Asthmatics with high CANO showed higher morbidity. No correlation was found between proximal and distal inflammation

Óxido nítrico exhalado e índice predictivo de asma en menores de dos años / Fraction of Exhaled Nitric Oxide and Asthma Predictive Index in Infants Less Than Two Years-Old

Introducción: La fracción exhalada del óxido nítrico (FENO) se considera marcador indirecto de la inflamacióneosinofílica de la vía aérea. En niños colaboradores la metodología habitual es mediante respiraciónúnica. La imposibilidad de realizarla en niños no colaboradores ha permitido desarrollar la técnica a respiracióncorriente on-line y off-line. El objetivo del estudio ha sido analizar la relación entre la FENO on-linea respiraciones múltiples y el índice predictivo de asma (IPA) en niños menores de dos años.Material y métodos: Estudio observacional y transversal en una muestra consecutiva de niños y niñas entredos meses y dos años de edad, durante un período de 4 meses. Se determinó la FENO postprandial onlinea respiración corriente con respiraciones múltiples y flujo espiratorio entre 40 y 60 ml/s, medianteanalizador de quimioluminiscencia estacionario (CLD 88 sp). Variables cuantitativas: edad, peso, IgE,eosinofilia, FENO, flujo espiratorio. Variables cualitativas: sexo, dermatitis atópica, rinitis alérgica, alergiaalimentaria y medicamentosa, antecedentes familiares de asma y atopia, diagnóstico y tratamiento. Seha analizado la asociación entre IPA y FENO mediante test exacto de Fisher y t de Student y el grado deacuerdo entre IPA y FENO mediante Kappa de Cohen. Se ha estudiado la relación entre eosinofilia, IgE,dermatitis atópica y FENO (test exacto de Fisher y t de Student).Resultados: Cohorte constituida por 38 pacientes. Realizaron las determinaciones con éxito 32 (84,21%)casos. Edad media 10,9±5,06 meses. Los casos con IPA positivo tenían valores de FENO significativamentesuperiores a los IPA negativos con grado de acuerdo entre IPA y FENO de 0,71.Conclusiones: Existe asociación significativa y un buen grado de acuerdo entre la FENO a respiracióncorriente online y el IPA(AU)

Introduction: The fraction of exhaled nitric oxide (FENO) is considered as an indirect marker of eosinophilicinflammation of the airway. In collaborating children the usual method is by a single breath. Theimpossibility of performing this in non-collaborating children has led to the development of the onlineand offline tidal breathing technique. The objective of the study has been to analyse the relationshipbetween the multiple breaths online FENO and the asthma predictive index (API) in children less than 2years-old.Material and methods: An observational and cross-sectional study on a consecutive sample of boys andgirls between 2 months and 2 years of age, over a period of 4 months. The post-prandial multiple breathsonline FENO and flow spirometry between 40 and 60 ml/s, using a stationary chemiluminescence analyser(CLD 88 sp). The quantitative variables were: age, weight, IgE, eosinophilia, FENO, flow spirometry. Thequalitative variables were: gender, atopic dermatitis, allergic rhinitis, food and medical allergies, familyhistory of asthma and atopy, diagnosis and treatment. The relationship between API and FENO was analysedusing the exact Fisher and Student t tests and the level of agreement between API and FENO usingCohen’s Kappa. The relationship between eosinophilia, IgE, atopic dermatitis and FENO was also studied(exact Fisher and Student t tests). Results: The cohort consisted of 38 patients. The determinations were successfully carried out on 32(84.21) of the cases. The mean age was 10.9±5.06 months. The cases with a positive API had significantlyhigher FENO values than those with a negative API, with a level of agreement between API and FENO of0.71.Conclusions: There is a significant relationship and a good level of agreement between the online tidalbreathing FENO and the API(AU)