Los Angeles phonospirometry technique: creating a normogram that correlates with peak expiratory flow measurements in children

Abstract

Objective: Measurement of peak expiratory flow (PEF) is recommended in the assessment of patients with asthma. However, the use of PEF involves multiple barriers, which have limited its use. Phonospirometry, as assessed by a novel Los Angeles phonospirometry technique, has shown good correlation to standard PEF measurements in a pilot study on symptomatic patients with asthma. We sought to develop a normogram for phonospirometry, and to validate the PEF normogram. Methods: A convenience sample of asymptomatic children ages 3–17 years old was approached for participation in the Emergency Department. Sample size calculations determined that at least 30 children per age group (n = 450) were needed. Children were asked to perform PEF measurements and phonospirometry, measured as the length of time (in s) the child was able to chant “lalala” in a single breath. Results: 510 children were enrolled. Spearman's rho between PEF and phonospirometry was 0.722. Phonospirometry correlated with both age and height, with a spearman rho of 0.697 and 0.696, respectively. This was slightly lower than the correlation of PEF with age and height with spearman rhos of 0.877 and 0.902, respectively. A normogram was developed for phonospirometry based on age and height. Conclusions: This study determined normal value ranges for the Los Angeles phonospirometry technique for age and height, and also showed that the technique has good correlation with PEF. This technique may be used to assess a pediatric patient with an acute asthma exacerbation.

• Children
• Los Angeles technique
• phonospirometry

Acknowledgements

The authors would like to thank Colleen G. Azen, M.S. of the GCRC/CTSI at Children’s Hospital Los Angeles for her support with the statistical analysis. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper. This work was supported in part by Grant Number UL1TR000130, Children’s Hospital Los Angeles from the National Center for Advancing Translational Sciences (NCATS) at the National Institute of Health.