title: In vitro and in vivo evaluation of a novel integrated wearable artificial lung.
abstract: BACKGROUND
  Conventional extracorporeal membrane oxygenation (ECMO) is cumbersome and is associated with high morbidity and mortality. We are currently developing the Pittsburgh Ambulatory Assist Lung (PAAL), which is designed to allow for ambulation of lung failure patients during bridge to transplant or recovery. In this study, we investigated the in vitro and acute in vivo performance of the PAAL.
  
  
  METHODS
  The PAAL features a 1.75-inch-diameter, cylindrical, hollow-fiber membrane (HFM) bundle of stacked sheets, with a surface area of 0.65 m2integrated with a centrifugal pump. The PAAL was tested on the bench for hydrodynamic performance, gas exchange and hemolysis. It was then tested in 40- to 60-kg adult sheep (n = 4) for 6 hours. The animals were cannulated with an Avalon Elite 27Fr dual-lumen catheter (DLC) inserted through the right external jugular into the superior vena cava (SVC), right atrium (RA) and inferior vena cava (IVC).
  
  
  RESULTS
  The PAAL pumped >250 mm Hg at 3.5 liters/min at a rotation speed of 2,100 rpm. Oxygenation performance met the target of 180 ml/min at 3.5 liters/min of blood flow in vitro, resulting in a gas-exchange efficiency of 278 ml/min/m2. The normalized index of hemolysis (NIH) for the PAAL and cannula was 0.054 g per 100 liters (n = 2) at 3.5 liters/min, as compared with 0.020 g per 100 liters (n = 2) for controls (DLC cannula and a Centrimag pump). Plasma-free hemoglobin (pfHb) was <20 mg/dl for all animals. Blood left the device 100% oxygenated in vivo and oxygenation reached 181 ml/min at 3.8 liters/min.
  
  
  CONCLUSIONS
  The PAAL met in vitro and acute in vivo performance targets. Five-day chronic sheep studies are planned for the near future.
authors.affiliation: McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Shalv P
authors.initials: SP
authors.lastname: Madhani
authors.affiliation: McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Frankowski
authors.affiliation: Computational Fluid Dynamics Group, Center for Advanced Vehicular Systems, Mississippi State University, Starkville, Mississippi, USA.
authors.forename: Greg W
authors.initials: GW
authors.lastname: Burgreen
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
authors.forename: Jim F
authors.initials: JF
authors.lastname: Antaki
authors.affiliation: Department of Surgery, University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, Pennsylvania, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Kormos
authors.affiliation: Department of Surgery, University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, Pennsylvania, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: D'Cunha
authors.affiliation: McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA. Electronic address: federspielwj@upmc.edu.
authors.forename: William J
authors.initials: WJ
authors.lastname: Federspiel
mesh_terms: D000818:Animals; D001187:Artificial Organs; D004195:Disease Models, Animal; D004867:Equipment Design; D015199:Extracorporeal Membrane Oxygenation / Q000295:instrumentation*; D008171:Lung Diseases / Q000628:therapy*; D012756:Sheep
keywords: COPD and ARDS; ambulatory ECMO; artificial lung; bridge to lung transplant; bridge to recovery; wearable respiratory support