Introduction

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.  

Aim

Study the feasibility and clinical value of AOS in children with acute wheezing in the CED.

Methods

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.  

Results

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). 

Conclusions

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.