title: Superior venous drainage in the "LifeBox": a portable extracorporeal oxygenator with a self-expanding venous cannula.
abstract: BACKGROUND
  In an experimental setting, the performance of the LifeBox, a new portable extracorporeal membrane oxygenator (ECMO) system suitable for patient transport, is presented. Standard rectilinear percutaneous cannulae are normally employed for this purpose, but have limited flow and pressure delivery due to their rigid structure. Therefore, we aimed to determine the potential for flow increase by using self-expanding venous cannulae.
  
  
  METHODS
  Veno-arterial bypass was established in three pigs (40.6+/-5.1 kg). The venous line of the cardiopulmonary bypass was established by cannulation of the external jugular vein. The arterial side of the circulation was secured by cannulation of the common carotid artery. Two different venous cannulae (SmartCanula 18/36F 430mm and Biomedicus 19F) were examined for their functional integrity when used in conjunction with the centrifugal pump (500-3000 RPM) of the LifeBox system.
  
  
  RESULTS
  At 1500, 2000, 2500, and 3000 RPM, the blood flow increased steadily for each cannula, but remained higher in the self-expanding cannula. That is, the 19F rectilinear cannula achieved a blood flow of 0.93+/-0.14, 1.47+/-0.37, 1.9+/-0.68, and 1.5+/-0.9 l/min, respectively, and the 18/36F self-expanding cannula achieved 1.1+/-0.1, 1.9+/-0.33, 2.8+/-0.39 and 3.66+/-0.52 l/min. However, when tested for venous line pressure, the standard venous cannula achieved -29+/-10.7mmHg while the self-expanding cannula achieved -13.6 +/-4.3mmHg at 1500 RMP. As the RPM increased from 2500 to 3000, the venous line pressure accounted for -141.9+/-20 and -98+/-7.3mmHg for the 19F rectilinear cannula and -30.6+/-6.4 and -45+/-11.6mmHg for the self-expanding cannula.
  
  
  CONCLUSIONS
  The self-expanding cannula exhibited superior venous drainage ability when compared to the performance of the standard rectilinear cannula with the use of the LifeBox. The flow rate achieved was approximately 40% greater than the standard drainage device, with a maximal pump flow recorded at 4.3l/min.
authors.affiliation: Department of Cardiovascular Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. denis.berdajs@chuv.ch
authors.forename: Denis
authors.initials: D
authors.lastname: Berdajs
authors.forename: Frank
authors.initials: F
authors.lastname: Born
authors.forename: Monique
authors.initials: M
authors.lastname: Crosset
authors.forename: Judith
authors.initials: J
authors.lastname: Horisberger
authors.forename: Andreas
authors.initials: A
authors.lastname: Künzli
authors.forename: Enrico
authors.initials: E
authors.lastname: Ferrari
authors.forename: Piergiorgo
authors.initials: P
authors.lastname: Tozzi
authors.forename: Ludwig K
authors.initials: LK
authors.lastname: von Segesser
mesh_terms: D000818:Animals; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D002405:Catheterization, Central Venous / Q000295:instrumentation*; D015199:Extracorporeal Membrane Oxygenation / Q000295:instrumentation* / Q000379:methods*; D006355:Heart-Lung Machine; D010107:Oxygenators, Membrane; D013552:Swine; D014690:Venous Pressure