title: Extracorporeal fetal support: a new animal model with preservation of the placenta.
abstract: BACKGROUND
  Previous models of support for premature sheep fetuses have consisted of cesarean delivery followed by catheterization of umbilical or central vessels and support with extracorporeal membrane oxygenation (ECMO). The limitations of these models have been insufficient blood flow, significant fetal edema, and hemorrhage related to anticoagulation.
  
  
  METHODS
  We performed a gravid hysterectomy on 13 ewes between 135 and 145days gestational age. The uterine vessels were cannulated bilaterally and circulatory support was provided via ECMO. Successful transition was defined as maintenance of fetal heart rate for 30minutes after establishing full extracorporeal support. Circuit flow was titrated to maintain mixed venous oxygen saturation (SvO2) of 70-75%.
  
  
  RESULTS
  Seven experiments were successfully transitioned to ECMO, with an average survival time of 2hours 9minutes. The longest recorded time from cannulation to death was 6hours 14minutes. By delivering a circuit flow of up to 2120ml/min, all but one of the transitioned uteri were maintained within the desired SvO2 range.
  
  
  CONCLUSIONS
  We report a novel animal model of fetal ECMO support that preserves the placenta, mitigates the effects of heparin, and allows for increased circuit flow compared to prior techniques. This approach may provide insight into a technique for future studies of fetal physiology.
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Jose H
authors.initials: JH
authors.lastname: Salazar
authors.affiliation: Department of Surgery, Columbia University, New York, NY.
authors.forename: Alodia
authors.initials: A
authors.lastname: Gabre-Kidan
authors.affiliation: Department of Surgery, Howard University College of Medicine, Washington, DC.
authors.forename: Gezzer
authors.initials: G
authors.lastname: Ortega
authors.affiliation: Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Diana
authors.initials: D
authors.lastname: Scorpio
authors.affiliation: Critical Care Medicine, Children's National Medical Center, Washington, DC.
authors.forename: Gary
authors.initials: G
authors.lastname: Oldenburg
authors.affiliation: Critical Care Medicine, University of Maryland Medical Center, Baltimore, MD.
authors.forename: Haven
authors.initials: H
authors.lastname: Custis
authors.affiliation: Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Dawn
authors.initials: D
authors.lastname: Ruben
authors.affiliation: Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Melanie
authors.initials: M
authors.lastname: Albano
authors.affiliation: Department of Preventive Medicine, Johns Hopkins School of Public Health, Baltimore, MD.
authors.forename: Shelly S
authors.initials: SS
authors.lastname: Choo
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Rhee
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: William B
authors.initials: WB
authors.lastname: Fulton
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Surgery, St Vincent Health, Indianapolis, IN.
authors.forename: Dominic
authors.initials: D
authors.lastname: Papandria
authors.affiliation: Department of Gynecology & Obstetrics, Johns Hopkins School of Medicine, Baltimore, MD.
authors.forename: Jude P
authors.initials: JP
authors.lastname: Crino
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD. Electronic address: fa@jhmi.edu.
authors.forename: Fizan
authors.initials: F
authors.lastname: Abdullah
mesh_terms: D000818:Animals; D001187:Artificial Organs; D015199:Extracorporeal Membrane Oxygenation; D005260:Female; D005333:Fetus / Q000098:blood supply* / Q000502:physiology; D023421:Models, Animal; D009926:Organ Preservation / Q000379:methods; D010920:Placenta / Q000098:blood supply* / Q000502:physiology; D011247:Pregnancy; D012756:Sheep; D014599:Uterus / Q000098:blood supply* / Q000601:surgery
keywords: Artificial placenta; ECMO; Fetal support; Fetus; Sheep