title: Ex vivo evaluation of nonacceptable donor lungs.
abstract: BACKGROUND
  Only a minority of the potential candidates for lung donation are considered suitable, using current evaluation methods. A new method for ex vivo evaluation, with the potential for reconditioning of marginal and nonacceptable lungs, has been developed. This is a report of the ex vivo evaluation of six donor lungs deemed nonacceptable (arterial oxygen pressure less than 40 kPa) by the Scandiatransplant, Eurotransplant, and UK transplant organizations.
  
  
  METHODS
  The lungs are perfused ex vivo with Steen solution, a lung evaluation-preservation solution, mixed with red blood cells to a hematocrit of 15%. This extracellular solution is designed to have an optimal colloid osmotic pressure so that physiologic pressure and flow can be maintained without development of pulmonary edema. An oxygenator connected to the extracorporeal circuit maintains a normal mixed venous blood gas level in the perfusate. The lungs are ventilated and evaluated through analyses of pulmonary vascular resistance, oxygenation capacity, and arterial carbon dioxide pressure minus end-tidal carbon dioxide difference.
  
  
  RESULTS
  The arterial oxygen pressure (inspired oxygen fraction, 1.0) increased from 27 kPa (range, 17 to 34 kPa) in situ in the organ donor at the referring hospital to 57 kPa (range, 39 to 66 kPa) during the ex vivo evaluation. The pulmonary vascular resistance varied from 3.2 to 5.7 Wood units, and the arterial carbon dioxide pressure minus end-tidal carbon dioxide difference was in the range of 1 to 2.5 kPa.
  
  
  CONCLUSIONS
  The arterial oxygen pressure improves significantly in this model. This ex vivo evaluation model is a valuable addition to the armamentarium in finding acceptable lungs in a donor population with inferior arterial oxygen pressure values.
authors.affiliation: Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden. pwi@sks.aaa.dk
authors.forename: Per
authors.initials: P
authors.lastname: Wierup
authors.forename: Asa
authors.initials: A
authors.lastname: Haraldsson
authors.forename: Folke
authors.initials: F
authors.lastname: Nilsson
authors.forename: Leif
authors.initials: L
authors.lastname: Pierre
authors.forename: Henrik
authors.initials: H
authors.lastname: Scherstén
authors.forename: Martin
authors.initials: M
authors.lastname: Silverborn
authors.forename: Trygve
authors.initials: T
authors.lastname: Sjöberg
authors.forename: Ulla
authors.initials: U
authors.lastname: Westfeldt
authors.forename: Stig
authors.initials: S
authors.lastname: Steen
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D006801:Humans; D007511:Ischemia; D008168:Lung / Q000098:blood supply / Q000502:physiology*; D016040:Lung Transplantation; D008962:Models, Theoretical; D009569:Nitric Oxide / Q000008:administration & dosage; D010100:Oxygen / Q000032:analysis*; D012016:Reference Values; D015424:Reperfusion; D014019:Tissue Donors; D014655:Vascular Resistance
chemical_list: D002245:Carbon Dioxide; D009569:Nitric Oxide; D010100:Oxygen