Children’s emergency department airwave oscillometry in school-age children with acute wheezing

<bold>Introduction:</bold> Lung Function Tests (LFT) are rarely performed in the Children’s Emergency Department (CED) to assess acute wheeze, despite their importance. Airwave oscillometry (AOS) is a quick, effort-independent, painless LFT measuring respiratory resistance and impedance that may be of use. <bold>Aim:</bold> Study the feasibility and clinical value of AOS in children with acute wheezing in the CED. <bold>Methods:</bold> Patients aged 6-14 years attending our CED with acute doctor-diagnosed wheeze were recruited. AOS and spirometry measurements were attempted pre- and post-bronchodilator (BD). AOS calculates Rrs11 reflecting lung resistance and Xrs11 reflecting lung reactance. <bold>Results:</bold> AOS was attempted in 22 participants (median age= 8.5 years [IQR= 7, 10]). 18 also attempted spirometry. 100% of participants (n= 22) produced acceptable AOS compared with 38.89% for spirometry (n= 7). Participant Z scores exceeded limits of normal at baseline in 45.45% (n= 10) for Rrs11 and 59.09% (n= 13) for Xrs11. AOS BD testing was successful in 17 participants. Post-BD, Z scores for Rrs11 did not change significantly (p= 0.49, mean Rrs11 Z score pre- vs post-BD= 2.50 vs 2.15) whereas Xrs11 did change significantly (p= 0.028, mean Xrs11 Z score pre- vs post-BD= –3.94 vs –2.56). <bold>Conclusions:</bold> AOS was more feasible than spirometry for assessing acutely wheezy participants. This likely reflects the effort-independent nature of AOS compared with spirometry. AOS detected abnormalities at baseline and improvements in lung function post-BD. However, universally agreed cut-off values are needed to interpret this. Xrs11 may be more useful than Rrs11 at assessing acutely wheezy patients, but more work is needed to establish this.