The link between exhaled NO and bronchomotor tone depends on the dose of inhaled steroid in asthma

Mahut, Bruno; Trinquart, Ludovic; Bokov, Plamen; Peiffer, Claudine; Delclaux, Christophe

doi:10.1016/j.rmed.2010.02.003

« Previous Next »Respiratory Medicine
Volume 104, Issue 7 , Pages 945-950, July 2010

The link between exhaled NO and bronchomotor tone depends on the dose of inhaled steroid in asthma

Bruno Mahut
- Cabinet La Berma, 4 avenue de la Providence, 92 160 Antony, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie – Clinique de la Dyspnée, Paris, France
- Mosquito Respiratory Research Group, Paris, France
Ludovic Trinquart
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Unité de Recherche Clinique et d'Epidémiologie, Paris, France
- Mosquito Respiratory Research Group, Paris, France
- University Paris Descartes, Paris, France
Plamen Bokov
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie – Clinique de la Dyspnée, Paris, France
- Mosquito Respiratory Research Group, Paris, France
Claudine Peiffer
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie – Clinique de la Dyspnée, Paris, France
- Mosquito Respiratory Research Group, Paris, France
Christophe Delclaux
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie – Clinique de la Dyspnée, Paris, France
- Mosquito Respiratory Research Group, Paris, France
- University Paris Descartes, Paris, France
- CIC 9201 Plurithématique, Hôpital Européen Georges Pompidou, Paris, France
- Corresponding author. Service de Physiologie – Clinique de la Dyspnée, Hôpital Européen Georges Pompidou, 20, rue Leblanc; 75015 Paris, France. Tel.: +33 1 56 09 34 88.

Received 28 September 2009; accepted 3 February 2010. published online 02 March 2010.

Summary

Background

Exhaled NO (FE_NO) is a steroid dose dependent eosinophilic inflammometer, but also a mediator of bronchomotor tone, but statistically significant relationships have infrequently been obtained with pulmonary function tests (PFT). The aim was to test the hypothesis that the relationships between FE_NO and PFT could be uncovered by inhaled corticosteroid (ICS) treatment, namely that a link between FE_NO and bronchodilator response (an index of bronchomotor tone) would appear under ICS.

Methods

Exhaled NO, forced expiratory flows and lung volumes were measured in atopic asthmatic children without recent (one month) respiratory symptoms.

Results

Two hundred and thirty children (mean±SD, age: 11.2±2.5 years, 69 girls) were included (% predicted, FEV₁: 100±14; FEF_50%: 76±23; RV: 107±29). The relationship between ICS dose (GINA classification) and FE_NO plateaued in children with an ICS dose higher than 200μg beclomethasone equipotent daily dose: FE_NO (median [25th–75th percentiles]), 43ppb [15–105] (no treatment, n=65), 33ppb [15–77] (low dose, n=70), 23ppb [12–57] (medium dose, n=57) and 26ppb [9–49] (high dose, n=38). Statistically significant relationships between FE_NO and PFT were only observed in children receiving more than 200μg/day ICS: with FEV₁ (medium ICS dose: ρ=0.43, p=0.001; high dose: ρ=0.32, p=0.052) and bronchodilator (400μg salbutamol) response (medium dose: ρ=0.54, p=0.001; high dose: ρ=0.65, p=0.002).

Conclusions

A positive correlation between FE_NO and bronchomotor tone appears with increasing ICS doses in atopic children with clinically controlled asthma, which further suggests that children depicting the highest FE_NO values may have lesser steroid sensitivity.

Keywords: Asthma, Childhood, Exhaled NO, Steroid sensitivity, Steroid resistance, Pulmonary function tests