Fractional exhaled nitric oxide (FeNO), Impulse Oscilometry (IOS) and clinical status in 4 to 7 years old asthmatic children

Abstract

Introduction: Respiratory functional evaluation in young children is an unresolved problem. FeNO give information about eosinophilic inflammation, and IOS, explore mechanical properties of the respiratory system. Its still not clear the relathionship between these studies and the clinical status.

Objective: Evaluate FeNO and IOS in 4-7 years old asthmatic children, estimate their relathionship with the clinical status and the relationship between both messures.

Population: Cross-section study on 4-7 years old children followed with diagnosis of asthma in the Pediatric Pulmonology Section of a General University Hospital.

Methods: Attempt was made to make FeNO and basal and post bronchodilator IOS messures in children comming to a scheduled control. After physical examen was performed added with a questionnaire of last month symptoms

Results: 77 children (median 5 years, 37 girls) were recluted. IOS was succesfull in all children. 18 can not hold espiratory flow to perform FeNO. So 59 % achieved both messures, median age 6 y.o. 90% (N=53) were treated with inhaled steroids; all had normal physical examen; 17 (29%) describe symptoms in the last month (wheezing ot persistent dry cought). Median FeNo was 14 ppb in symptomatics and y 15 ppb in asymptomatics ( P 0,39). Basal IOS for symptomatic children shaws R5HZ 0.91 and asymptomatic 0.93 (P 0,43). Basal reactance (X5HZ) was -0,19 in symtomatics and -0,18 in asymtomatics (P 0,749). We did not find correlation betwen FeNO and basal IOS (r=0,01).

Conclusions: For youngest children IOS was easier to perform than FeNO. We did not find differences in FeNO or basal IOS between symptomatic and asymptomatic children.