Ex vivo evaluation of nonacceptable donor lungs.
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.
Wierup
Per
P
Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden. pwi@sks.aaa.dk
Haraldsson
Asa
A
Nilsson
Folke
F
Pierre
Leif
L
Scherstén
Henrik
H
Silverborn
Martin
M
Sjöberg
Trygve
T
Westfeldt
Ulla
U
Steen
Stig
S
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
D002245:Carbon Dioxide; D009569:Nitric Oxide; D010100:Oxygen