title: Pressure-limited sustained inflation vs. gradual tidal inflations for resuscitation in preterm lambs.
abstract: Support of the mechanically complex preterm lung needs to facilitate aeration while avoiding ventilation heterogeneities: whether to achieve this gradually or quickly remains unclear. We compared the effect of gradual vs. constant tidal inflations and a pressure-limited sustained inflation (SI) at birth on gas exchange, lung mechanics, gravity-dependent lung volume distribution, and lung injury in 131-day gestation preterm lambs. Lambs were resuscitated with either 1) a 20-s, 40-cmH2O pressure-limited SI (PressSI), 2) a gradual increase in tidal volume (Vt) over 5-min from 3 ml/kg to 7 ml/kg (IncrVt), or 3) 7 ml/kg Vt from birth. All lambs were subsequently ventilated for 15 min with 7 ml/kg Vt with the same end-expiratory pressure. Lung mechanics, gas exchange and spatial distribution of end-expiratory volume (EEV), and tidal ventilation (electrical impedance tomography) were recorded regularly. At 15 min, early mRNA tissue markers of lung injury were assessed. The IncrVt group resulted in greater tissue hysteresivity at 5 min (P = 0.017; two-way ANOVA), higher alveolar-arterial oxygen difference from 10 min (P < 0.01), and least uniform gravity-dependent distribution of EEV. There were no other differences in lung mechanics between groups, and the PressSI and 7 ml/kg Vt groups behaved similarly throughout. EEV was more uniformly distributed, but Vt least so, in the PressSI group. There were no differences in mRNA markers of lung injury. A gradual increase in Vt from birth resulted in less recruitment of the gravity-dependent lung with worse oxygenation. There was no benefit of a SI at birth over mechanical ventilation with 7 ml/kg Vt.
authors: Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia;
authors: David G
authors: http://orcid.org/0000-0003-1522-4691
authors: DG
authors: Tingay
authors: The Ritchie Centre, MIMR-PHI Institute of Medical Research, Clayton, Victoria, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia;
authors: Graeme R
authors: GR
authors: Polglase
authors: Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia;
authors: Risha
authors: R
authors: Bhatia
authors: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia;
authors: Clare A
authors: CA
authors: Berry
authors: CAS Medical Systems Inc., Branford, Connecticut;
authors: Robert J
authors: RJ
authors: Kopotic
authors: CAS Medical Systems Inc., Branford, Connecticut;
authors: Clinton P
authors: CP
authors: Kopotic
authors: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia;
authors: Yong
authors: Y
authors: Song
authors: Universidad Abierta Interamericana (UAI), Buenos Aires, Argentina; Icahn School of Medicine at Mount Sinai, New York, New York; and.
authors: Edgardo
authors: E
authors: Szyld
authors: Cincinnati Children's Hospital Medical Centre, Cincinnati, Ohio.
authors: Alan H
authors: AH
authors: Jobe
authors: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia; jane.pillow@uwa.edu.au.
authors: J Jane
authors: JJ
authors: Pillow
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D055370:Lung Injury / Q000503:physiopathology* / Q000628:therapy*; D011175:Positive-Pressure Respiration / Q000379:methods*; D011312:Pressure; D012121:Respiration, Artificial / Q000379:methods*; D012151:Resuscitation / Q000379:methods*; D012756:Sheep; D016896:Treatment Outcome
keywords: infant; lung recruitment; mechanical ventilation; newborn; resuscitation; ventilation homogeneity
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