title: Pressure- versus volume-limited sustained inflations at resuscitation of premature newborn lambs.
abstract: BACKGROUND
  Sustained inflations (SI) are advocated for the rapid establishment of FRC after birth in preterm and term infants requiring resuscitation. However, the most appropriate way to deliver a SI is poorly understood. We investigated whether a volume-limited SI improved the establishment of FRC and ventilation homogeneity and reduced lung inflammation/injury compared to a pressure-limited SI.
  
  
  METHODS
  131 d gestation lambs were resuscitated with either: i) pressure-limited SI (PressSI: 0-40 cmH2O over 5 s, maintained until 20 s); or ii) volume-limited SI (VolSI: 0-15 mL/kg over 5 s, maintained until 20 s). Following the SI, all lambs were ventilated using volume-controlled ventilation (7 mL/kg tidal volume) for 15 min. Lung mechanics, regional ventilation distribution (electrical impedance tomography), cerebral tissue oxygenation index (near infrared spectroscopy), arterial pressures and blood gas values were recorded regularly. Pressure-volume curves were performed in-situ post-mortem and early markers of lung injury were assessed.
  
  
  RESULTS
  Compared to a pressure-limited SI, a volume-limited SI had increased pressure variability but reduced volume variability. Each SI strategy achieved similar end-inflation lung volumes and regional ventilation homogeneity. Volume-limited SI increased heart-rate and arterial pressure faster than pressure-limited SI lambs, but no differences were observed after 30 s. Volume-limited SI had increased arterial-alveolar oxygen difference due to higher FiO2 at 15 min (p = 0.01 and p = 0.02 respectively). No other inter-group differences in arterial or cerebral oxygenation, blood pressures or early markers of lung injury were evident.
  
  
  CONCLUSIONS
  With the exception of inferior oxygenation, a sustained inflation targeting delivery to preterm lambs of 15 mL/kg volume by 5 s did not influence physiological variables or early markers of lung inflammation and injury at 15 min compared to a standard pressure-limited sustained inflation.
authors: Graeme R
authors: GR
authors: Polglase
authors: David G
authors: DG
authors: Tingay
authors: Risha
authors: R
authors: Bhatia
authors: Clare A
authors: CA
authors: Berry
authors: Robert J
authors: RJ
authors: Kopotic
authors: Clinton P
authors: CP
authors: Kopotic
authors: Yong
authors: Y
authors: Song
authors: Edgardo
authors: E
authors: Szyld
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. jane.pillow@uwa.edu.au.
authors: Jane J
authors: JJ
authors: Pillow
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D005652:Functional Residual Capacity; D055370:Lung Injury / Q000517:prevention & control; D008297:Male; D011312:Pressure; D012151:Resuscitation / Q000379:methods*; D012756:Sheep