Influence of bronchopulmonary dysplasia on breathing pattern after a sigh in preterm neonates

Abstract

Introduction

Reduced variability in time series of physiological signals has been associated with increased morbidity and mortality. We aimed to assess whether variability of tidal volume (VT) following a sigh is associated with the severity of bronchopulmonary dysplasia (BPD) and the degree of maturity at birth (gestational age, GA) in preterm infants.

Methods

We performed tidal breathing measurements according to European Respiratory Society standards in infants during quiet unsedated sleep. Tests were performed at a mean postconceptional age of 44.8 (range 41.9-51.9) weeks using an ultrasonic flowmeter. BPD was defined according to the National Institutes of Health consensus definition. Variability of VT was explored using moving-window coefficient of variation in VT (CV_VT) over 16 breaths at baseline (CV_VT,base), immediately after a sigh (CV_VT,post), and at the end of a measurement (CV_VT,end). We used multiple linear regression to analyse outcomes.

Results

We examined a total of 244 sighs in 145 infants: Term healthy infants (TH, n=86); preterm infants without BPD (PT-noBPD, n=23); preterm infants with mild (n=12), moderate (n=15), and severe (n=9) BPD (PT-BPD). CV_VT,post but not CV_VT,base or CV_VT,end was lower in PT-BPD vs. PT-noBPD and TH infants (p<0.001, R²=0.16). CV_VT,post but not CV_VT,base or CV_VT,end was negatively associated with the degree of BPD (p<0.001, R²=0.20). Adding GA as a covariable did not increase the predictive value of the models.

Conclusion

Neonatal lung disease is a predictor of variability in VT immediately after a sigh in preterm infants. Presence and severity of BPD rather than the degree of maturity at birth influence breathing pattern after a sigh.