Noninvasive Testing of Lung Function and Inflammation in Pediatric Patients with Acute Asthma Exacerbations

Abstract

Objective. There is limited information on performance rates for tests of lung function and inflammation in pediatric patients with acute asthma exacerbations. We sought to examine how frequently pediatric patients with acute asthma exacerbations could perform noninvasive lung function and exhaled nitric oxide (FE_NO) testing and participant characteristics associated with successful performance. Methods. We studied a prospective convenience sample aged 5–17 years with acute asthma exacerbations in a pediatric emergency department. Participants attempted spirometry for percent predicted forced expiratory volume in 1 second (%FEV₁), airway resistance (Rint), and FE_NO testing before treatment. We examined overall performance rates and the associations of age, gender, race, and baseline acute asthma severity score with successful test performance. Results. Among 573 participants, age was (median [interquartile range]) 8.8 [6.8, 11.5] years, 60% were male, 57% were African-American, and 58% had Medicaid insurance. Tests were performed successfully by the following [n (%)]: full American Thoracic Society–European Respiratory Society criteria spirometry, 331 (58%); Rint, 561 (98%); and FE_NO, 354 (70% of 505 attempted test). Sixty percent with mild–moderate exacerbations performed spirometry compared to 17% with severe exacerbations (p = .0001). Participants aged 8–12 years (67%) were more likely to perform spirometry than those aged 5–7 years (48%) (OR = 2.23, 95% CI: 1.45–3.11) or 13–17 years (58%) (OR = 1.61, 95% CI: 1.00–2.59). Conclusions. There is clinically important variability in performance of these tests during acute asthma exacerbations. The proportion of patients with severe exacerbations able to perform spirometry (17%) limits its utility. Almost all children with acute asthma can perform Rint testing, and further development and validation of this technology is warranted.

• airway resistance
• asthma
• asthma exacerbation
• lung function testing
• spirometry

Acknowledgments

The authors gratefully acknowledge Donald J. Resha, EMT-P, for participant recruitment, and the nurses, respiratory therapists, and staff of the Vanderbilt Children’s Hospital Emergency Department for their assistance.

This research was supported by the National Institutes of Health: [K23 HL80005-01A2] (Dr. Arnold); NIAID [K24 AI77930] (Dr. Hartert); and NIH/NCRR [UL1 RR024975] (Vanderbilt CTSA).

Declaration of Interest

Aerocrine Corporation supplied the NIOX MINO nitric oxide monitor for this study. The authors have no other conflicts of interest to report. The authors alone are responsible for the content and writing of the paper.