Development of an artificial placenta I: pumpless arterio-venous extracorporeal life support in a neonatal sheep model.
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.
Reoma
Junewai L
JL
Department of Surgery, University of Michigan, Ann Arbor, USA.
Rojas
Alvaro
A
Kim
Anne C
AC
Khouri
Joseph S
JS
Boothman
Erika
E
Brown
Kristy
K
Grotberg
James
J
Cook
Keith E
KE
Bartlett
Robert H
RH
Hirschl
Ronald B
RB
Mychaliska
George B
GB
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