Wheeze monitoring in children for assessment of nocturnal asthma and response to therapy

The utilisation of nocturnal wheeze monitoring and quantification for assessment of asthma activity was studied in symptomatic school-aged children before and during treatment. Twelve children 6-14 yrs of age with mild or moderate untreated asthma were studied at home three times: before, 48 h and 6 weeks into treatment with 5 mg montelukast daily. Lung sounds were recorded overnight by an automatic wheeze detection device (Pulmo Track®). Per cent wheezing within each respiratory cycle was calculated every 30 s throughout the night and a Nocturnal Wheeze Index (NWI) was calculated for the total night. The results were compared with spirometric indices (forced expiratory volume in one second (FEV₁), forced vital capacity), bronchial reactivity (provocative concentration causing a 20% fall in FEV₁ by adenosine 5′-monophosphate (PC₂₀)) and daily symptom scores, performed in parallel at each stage of the study. The pretreatment NWI was 814±898 (mean±SD), which declined to 318±199 2 days after onset, and to 137±101 after 6 weeks of treatment. The NWI in seven healthy children was 47±43. The FEV₁, PC₂₀ and symptom scores improved in parallel. Wheeze monitoring provides quantitative and noninvasive information about the extent of nocturnal wheezing in children, correlates well with conventional indices of asthma activity and can assist in assessing efficacy of treatment.