title: Development of an ultra mini-oxygenator for use in low-volume, buffer-perfused preparations.
abstract: BACKGROUND
  Small animal models are widely used in basic research. However, experimental systems requiring extracorporeal circuits are frequently confronted with limitations related to equipment size. This is particularly true for oxygenators in systems with limited volumes. Thus we aimed to develop and validate an ultra mini-oxygenator for low-volume, buffer-perfused systems.
  
  
  METHODS
  We have manufactured a series of ultra mini-oxygenators with approximately 175 aligned, microporous, polypropylene hollow fibers contained inside a shell, which is sealed at each of the two extremities to isolate perfusate and gas compartments. With this construction, gas passes through hollow fibers, while perfusate circulates around fibers. Performance of ultra mini-oxygenators (oxygen partial pressure (PO2), gas and perfusate flow, perfusate pressure and temperature drop) were assessed with modified Krebs-Henseleit buffer in an in vitro perfusion circuit and an ex vivo rat heart preparation.
  
  
  RESULTS
  Mean priming volume of ultra mini-oxygenators was 1.2±0.5 mL and, on average, 86±6% of fibers were open (n=17). In vitro, effective oxygenation (PO2=400-500 mmHg) was achieved for all flow rates up to 50 mL/min and remained stable for at least 2 hours (n=5). Oxygenation was also effective and stable (PO2=456±40 mmHg) in the isolated heart preparation for at least 60 minutes ("venous" PO2=151±11 mmHg; n=5).
  
  
  CONCLUSIONS
  We have established a reproducible procedure for fabrication of ultra mini-oxygenators, which provide reliable and stable oxygenation for at least 60-120 min. These oxygenators are especially attractive for pre-clinical protocols using small, rather than large, animals.
authors.affiliation: Department of Cardiovascular Surgery, Inselspital, Berne University Hospital and University of Berne, Berne - Switzerland.
authors.forename: Marion
authors.initials: M
authors.lastname: Berner
authors.forename: David
authors.initials: D
authors.lastname: Clément
authors.forename: Mathieu
authors.initials: M
authors.lastname: Stadelmann
authors.forename: Michael
authors.initials: M
authors.lastname: Kistler
authors.forename: Yves
authors.initials: Y
authors.lastname: Boone
authors.forename: Thierry P
authors.initials: TP
authors.lastname: Carrel
authors.forename: Hendrik T
authors.initials: HT
authors.lastname: Tevaearai
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Longnus
mesh_terms: D000818:Animals; D004867:Equipment Design; D015199:Extracorporeal Membrane Oxygenation / Q000295:instrumentation*; D023421:Models, Animal; D010107:Oxygenators, Membrane; D051381:Rats