Single Breath Counting for Diagnosis and Prediction of Severity of Acute Asthma Exacerbation in Children

Abstract

Objectives: To find correlation between single breath counting (SBC) and spirometry in acute exacerbation of asthma in children.

Methods: A cross-sectional observational study including all children aged 6-12 y age, who presented in outpatient department or emergency room with acute exacerbation of asthma, not fitting in exclusion criteria were enrolled. SBC and spirometry parameters were obtained before treatment and 1 h after initiating treatment (GINA 2017 Guidelines).

Results: Significant correlation was observed in SBC and FVC (r = 0.349), FEV₁ (r = 0.439), FEF_25-75 (r = 0.424), and PEF (r = 0.593). Cutoff value of SBC of 23 was found to be suggestive of severe/life-threatening asthma with sensitivity of 83.3% and specificity of 84.4%. No significant association was found between percent change in SBC and spirometry parameters in response to treatment.

Conclusions: SBC can be used to predict PEF, FEV₁, FVC, and FEF_25-75 of a patient aged between 6 and 12 y during acute asthma exacerbation. The observed cutoff value of 23 of SBC score has a good sensitivity and specificity to identify life-threatening/severe exacerbation. SBC score significantly increases in response to therapy.

Keywords: Asthma; Child; Children; Lung volumes; Spirometry.