title: Influence of respiratory dead space on lung clearance index in preterm infants.
abstract: Lung clearance index (LCI), a marker of ventilation inhomogeneity derived from multiple breath washout (MBW), is used for clinical monitoring and as a key outcome of clinical trials in infants and children with cystic fibrosis. Utility of LCI is controversial in preterm infants with bronchopulmonary dysplasia (BPD) who tend to have high dead space to tidal volume ratio (VD/VT). We investigated the effect of VD/VT on LCI in a cohort of preterm infants with and without BPD and term healthy controls. We analyzed MBW data from 455 infants at a mean (SD) of 43.4 (3.5) w postmenstrual age. VD was estimated from the molar mass signal of an ultrasonic flowmeter (VD,MM). LCI was associated with VD,MM/VT (r(2)=0.13, p<0.001) but was not associated with BPD. Adjusting for VD,MM/VT did not reveal an association between LCI and BPD. We conclude that VD,MM/VT is a relevant factor when interpreting LCI in this population but the effect size of this association is moderate.
authors.affiliation: Department of Neonatology, University of Basel Children's Hospital, Basel, Switzerland. Electronic address: roland.neumann@ukbb.ch.
authors.forename: Roland P
authors.initials: RP
authors.lastname: Neumann
authors.affiliation: Centre of Neonatal Research and Education, School of Pediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, Australia.
authors.forename: J Jane
authors.initials: JJ
authors.lastname: Pillow
authors.affiliation: Woolcock Institute of Medical Research, Glebe, Australia.
authors.forename: Cindy
authors.initials: C
authors.lastname: Thamrin
authors.affiliation: Department of Respiratory Medicine, University of Basel Children's Hospital, Basel, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Frey
authors.affiliation: Department of Neonatology, University of Basel Children's Hospital, Basel, Switzerland; Centre of Neonatal Research and Education, School of Pediatrics and Child Health, University of Western Australia, Perth, Australia.
authors.forename: Sven M
authors.initials: SM
authors.lastname: Schulzke
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000503:physiopathology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D012126:Respiratory Dead Space / Q000502:physiology*; D012129:Respiratory Function Tests
keywords: Bronchopulmonary dysplasia; Infants; Lung clearance index; Respiratory dead space