Evaluation of an Oxygenator in the EXTra-Uterine Environment for Neonatal Development (EXTEND) System Without Systemic Anticoagulation

An important goal in the development of an artificial womb is the avoidance of the use of heparin, due to the presumed risk of intracranial hemorrhage in premature infants. We developed the Experimental Oxygenator (Exp-Ox), featuring a small surface area and low priming volume, as an oxygenator to support the clinical application of the EXTra-uterine Environment for Neonatal Development (EXTEND) system. This study evaluated the durability and hemocompatibility of the Exp-Ox during prolonged use (exceeding 14 days) in premature lambs in the EXTEND system without systemic anticoagulation (heparin-free study) compared to the standard heparin-based EXTEND system (heparin study). Twelve animals (91-93 days gestational age) completed the study: six in the heparin and six in the heparin-free study. Oxygen and CO2 transfer per weight remained stable overall in both studies, with no significant differences observed in oxygen transfer efficiency between the studies (p = 0.61). The quantitative clot burden of the Exp-Ox on computed tomography scan images ranged from 3.91-29.94% to 1.28-11.77% in the heparin and heparin-free studies, respectively (p = 0.15, nonsignificant difference), with no correlation to study duration or oxygen transfer efficiency. The Exp-Ox sustained function and hemocompatibility for over 14 days in the EXTEND system without systemic anticoagulation.