title: Development of an artificial placenta I: pumpless arterio-venous extracorporeal life support in a neonatal sheep model.
abstract: OBJECTIVE
  Effective treatment of respiratory failure in premature infants remains an unsolved problem. The development of an artificial placenta, in the form of a pumpless arteriovenous extracorporeal life support (AV-ECLS) circuit that maintains fetal circulation, is an appealing alternative.
  
  
  METHODS
  A near-term (140 d/term = 145 days) neonatal lamb model was used (n = 7). Fetuses were exposed by hysterotomy, and flow probes were placed on the ductus arteriosus, aorta, and carotid artery. Catheters were placed into the umbilical vessels, and pumpless AV-ECLS was initiated. Fetuses were submerged in a warm saline bath, and support was maintained for up to 4 hours.
  
  
  RESULTS
  Mean initial device flow was 383 mL/min but steadily declined to 177 mL/min at 4 hours. Mean initial pO(2) was 24 mm Hg and 18 mm Hg at 4 hours. Initial mean pCO(2) was 60 mm Hg and declined to 42 mm Hg at 4 hours. Mean arterial pressure was initially 43 mm Hg and decreased to 34 mm Hg at 4 hours. Flow in the ductus arteriosus was maintained for 4 hours. Of 7 fetuses, 5 survived 4 hours of support.
  
  
  CONCLUSIONS
  Pumpless AV-ECLS can support gas exchange and maintain fetal circulation in a neonatal lamb model for a 4-hour period. Prolonged support (>4 hours) is hampered by high cannula resistance and declining device flow.
authors.affiliation: Department of Surgery, University of Michigan, Ann Arbor, USA.
authors.forename: Junewai L
authors.initials: JL
authors.lastname: Reoma
authors.forename: Alvaro
authors.initials: A
authors.lastname: Rojas
authors.forename: Anne C
authors.initials: AC
authors.lastname: Kim
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Khouri
authors.forename: Erika
authors.initials: E
authors.lastname: Boothman
authors.forename: Kristy
authors.initials: K
authors.lastname: Brown
authors.forename: James
authors.initials: J
authors.lastname: Grotberg
authors.forename: Keith E
authors.initials: KE
authors.lastname: Cook
authors.forename: Robert H
authors.initials: RH
authors.lastname: Bartlett
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Hirschl
authors.forename: George B
authors.initials: GB
authors.lastname: Mychaliska
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010920:Placenta; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012131:Respiratory Insufficiency / Q000628:therapy*; D012756:Sheep