title: Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator.
abstract: OBJECTIVE
  Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (<2-3 ml) are available for surgery in small animals. We have designed a new, miniaturized membrane oxygenator and investigated the oxygen-transfer performance using both buffer and blood perfusates.
  
  
  METHODS
  The mini-oxygenator was designed with a central perforated core-tube surrounded by parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed.
  
  
  RESULTS
  Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h.
  
  
  CONCLUSIONS
  We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (<2 ml) and adequate oxygenation performance. This oxygenator may be of use in overcoming current limitations in equipment size for effective oxygenation in low-volume perfusion circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion.
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Felice
authors.initials: F
authors.lastname: Burn
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Sorin
authors.initials: S
authors.lastname: Ciocan
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Natalia Mendez
authors.initials: NM
authors.lastname: Carmona
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Marion
authors.initials: M
authors.lastname: Berner
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Joevin
authors.initials: J
authors.lastname: Sourdon
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Thierry P
authors.initials: TP
authors.lastname: Carrel
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland hendrik.tevaearai@insel.ch.
authors.forename: Hendrik T
authors.initials: HT
authors.lastname: Tevaearai Stahel
authors.affiliation: Clinic for Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Longnus
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000379:methods*; D004867:Equipment Design; D015199:Extracorporeal Membrane Oxygenation / Q000295:instrumentation*; D006331:Heart Diseases / Q000097:blood* / Q000601:surgery; D008904:Miniaturization; D010100:Oxygen / Q000097:blood*; D010107:Oxygenators, Membrane; D013552:Swine
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Blood oxygenation; Isolated perfused organ; Mini-oxygenator; Miniaturized membrane oxygenator; Small animal extracorporeal circulation; Small animal model