Accuracy of optoelectronic plethysmography in childhood exercise-induced asthma

ABSTRACT

Objective: To assess the variations of end-expiratory volume of chest wall (EEVcw) measured by optoelectronic plethysmography (OEP) as a diagnostic tool in exercise-induced asthma (EIA) among asthmatic preschool children. Methods: Forty children diagnosed with asthma were included in the study. Spirometry was used as a gold standard test for comparison with OEP. A 10% decline in forced expiratory volume in 1 second was considered positive for EIA. OEP was performed with 8 cameras at a frequency of 60 Hz and 89 markers were placed on the thoraco-abdominal surface of participants. Following bronchoprovocation testing on a treadmill, series of OEP and spirometry were conducted between 5 and 30 minutes after exercise. To obtain the ideal cut-off point, a receiver operating characteristic (ROC) curve was constructed for the largest EEVcw. The highest Youden index was used as criteria to obtain the cut-off point with the best sensitivity and specificity. Results: Of the 40 children studied, 16 had EIA. According to the ROC curve, the cut-off point of 0.185% for EEWcw provided mean sensitivity (95% confidence interval) of 93.75% (0.69–0.99), for a specificity of 83.33% (0.63–0.95), when using the largest increase in the period of 5–30 minutes post-exercise. The low area of the ROC was 0.93 (0.85–1.00) for p < 0.001. Conclusion: OEP can be accurately used to replace spirometry in asthmatic children unable to adequately execute the required manoeuvres.

KEYWORDS:

• Diagnostic techniques
• respiratory system
• signs and symptoms
• respiratory
• sensitivity and specificity
• respiratory mechanics and image processing
• computer-assisted

Acknowledgements

The authors are grateful to Professors Andréa Lemos, Daniella Cunha Brandão, Patrícia Bezerra, and Maria Cristina Falcão Raposo for their assistance in revising the manuscript.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

Fundação de Amparo a Ciência e Tecnologia do Estado de Pernambuco (FACEPE). APQ 0154-4.08/15. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)/Programa Nacional de Cooperação Acadêmica (PROCAD). 88881.068409/2014-0.