An artificial placenta (AP) using venovenous extracorporeal life support (VV-ECLS) could represent a paradigm shift in the treatment of extremely premature infants. However, AP support could potentially alter cerebral oxygen delivery. We assessed cerebral perfusion in fetal lambs on AP support using near-infrared spectroscopy (NIRS) and carotid arterial flow (CAF). Fourteen premature lambs at estimated gestational age (EGA) 130 days (term = 145) underwent cannulation of the right jugular vein and umbilical vein with initiation of VV-ECLS. An ultrasonic flow probe was placed around the right carotid artery (CA), and a NIRS sensor was placed on the scalp. Lambs were not ventilated. CAF, percentage of regional oxygen saturation (rSO2) as measured by NIRS, hemodynamic data, and blood gases were collected at baseline (native placental support) and regularly during AP support. Fetal lambs were maintained on AP support for a mean of 55 ± 27 hours. Baseline rSO2 on native placental support was 40% ± 3%, compared with a mean rSO2 during AP support of 50% ± 11% (p = 0.027). Baseline CAF was 27.4 ± 5.4 ml/kg/min compared with an average CAF of 23.7 ± 7.7 ml/kg/min during AP support. Cerebral fractional tissue oxygen extraction (FTOE) correlated negatively with CAF (r = −0.382; p < 0.001) and mean arterial pressure (r = −0.425; p < 0.001). FTOE weakly correlated with systemic O2 saturation (r = 0.091; p = 0.017). Cerebral oxygenation and blood flow in premature lambs are maintained during support with an AP. Cerebral O2 extraction is inversely related to carotid flow and is weakly correlated with systemic O2 saturation.
From the *Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, Michigan
†Department of Pediatrics & Communicable Diseases, University of Michigan, Ann Arbor, Michigan.
Submitted for consideration March 2017; accepted for publication in revised form August 2017.
Ahmed M. El-Sabbagh and Brian W. Gray contributed equally to this article.
Disclosure: The authors have no conflicts of interest to report.
This work was supported by National Institutes of Health grant # 1R01HD073475-01A1, the Helen L. Kay Charitable Foundation, the Hartwell Foundation Biomedical Research Fellowship, and the University of Michigan Undergraduate Research Opportunity Program.
Correspondence: Alvaro Rojas-Pena, MD, Extracorporeal Life Support Laboratory, Department of Surgery, Section of Transplantation, University of Michigan Medical School, 11509 W. Medical Center Dr, MSRB II, Room B560, Ann Arbor, MI 48109. Email: firstname.lastname@example.org.