An extra-uterine system to physiologically support the extreme premature lamb

TLDR

Extreme prematurity is the leading cause of neonatal mortality and morbidity in the developed world, and extracorporeal systems have so far achieved limited success in extending gestation. The authors aim to develop an extra‑uterine system that supports extreme‑premature lambs by connecting a pumpless oxygenator to the fetus via an umbilical‑cord interface within a closed amniotic‑fluid circuit that mimics the womb. The system employs a pumpless oxygenator circuit linked to the fetal umbilical cord and maintained in a closed, amniotic‑fluid environment to physiologically support the fetus. The device enabled developmentally equivalent lambs to survive up to four weeks with stable hemodynamics, normal blood gases, maintained fetal circulation, and normal somatic, pulmonary, and cerebral growth and myelination.

Abstract

Abstract In the developed world, extreme prematurity is the leading cause of neonatal mortality and morbidity due to a combination of organ immaturity and iatrogenic injury. Until now, efforts to extend gestation using extracorporeal systems have achieved limited success. Here we report the development of a system that incorporates a pumpless oxygenator circuit connected to the fetus of a lamb via an umbilical cord interface that is maintained within a closed ‘amniotic fluid’ circuit that closely reproduces the environment of the womb. We show that fetal lambs that are developmentally equivalent to the extreme premature human infant can be physiologically supported in this extra-uterine device for up to 4 weeks. Lambs on support maintain stable haemodynamics, have normal blood gas and oxygenation parameters and maintain patency of the fetal circulation. With appropriate nutritional support, lambs on the system demonstrate normal somatic growth, lung maturation and brain growth and myelination.