Correlation between impulse oscillometry and spirometry outcomes in a cohort of extremely preterm 6-year olds and controls

Abstract

Background: Extremely preterm birth before 28 weeks of gestation is a risk factor for chronic lung morbidity. Lung function follow up is therefore important in this group. Dynamic spirometry is the most widely used method, but impulse oscillometry (IOS) has been shown to be easier to perform in young children. Correlation between spirometry and IOS parameters has not been investigated in children born extremely preterm. Aim: To investigate the feasibility of performing, and to evaluate the correlation between spirometry and IOS outcomes in 6 year-old-children born extremely preterm. Methods: Spirometry and IOS were performed according to ERS guidelines in 6-year old children born extremely preterm (n=88) and term controls (n=84) in Stockholm, Sweden. Correlation between IOS and spirometry parameters were analyzed in the preterm group using Pearson’s partial correlation adjusting for height. Results: Success rates for spirometry and IOS did not differ significantly between the preterm and term groups (93% and 94% for IOS, p=0.79; 57% and 64% for spirometry, p=0.33). Spirometry and IOS outcomes correlated significantly in the preterm group, where the strongest estimates were found between Forced Expiratory Volume at 0.75 seconds (FEV0.75) and Reactance area (Ax), Table 1. Conclusion: Our results suggest that young children born extremely preterm have the same difficulties in performing spirometry as children born term. Further, spirometry and IOS parameters correlate significantly in children born extremely preterm.