COMPARISON OF LOW POTASSIUM EURO-COLLINS SOLUTION AND STANDARD EURO-COLLINS SOLUTION IN AN EXTRACORPOREAL RAT HEART-LUNG MODEL

Objective. Euro-Collins solution (EC) is routinely used in lung transp lantation. The high potassium of EC, however, may damage the vascular endothelium, thereby contributing to postischemic reperfusion injury. To assess the influence of the potassium concentration on lung preserv ation, we evaluated the effect of a ''low potassium Euro-Collins solut ion'' (LPEC), in which the sodium and potassium concentrations were re versed. Methods. In an extracorporeal rat heart-lung model lungs were preserved with EC and LPEC. The heart-lung blocks (HLB) were perfused with Krebs-Henseleit solution containing washed bovine red blood cells and ventilated with room air. The lungs were perfused via the working right ventricle with deoxygenated perfusate. Oxygenation and pulmonar y vascular resistance (PVR) were monitored. After baseline measurement s, hearts were arrested with St. Thomas' solution and the lungs were p erfused with EC or LPEC, or were not perfused (controls). The HLBs wer e stored for 5 min or 2 h ischemic time at 4 degrees C. Reperfusion an d ventilation was performed for 40 min. At the end of the trial the we t/dry ratio of the lungs was calculated and light microscopic assessme nt of the degree of edema was performed. Results. After 5 min of ische mia oxygenation was significantly better in both preserved groups comp ared to the controls. Pulmonary vascular resistance was elevated in al l three groups after 30 min reperfusion at both ischemic times. After 2 h of ischemia PVR of the group preserved with LPEC was significantly lower than those of the EC and controls (LPEC-5 min: 184 +/- 65 dynes sec * cm(-5), EC-5 min: 275 +/- 119 dynes * sec * cm * cm(-5), LPEC -2 h: 324 +/- 47 dynes sec * m(-5), EC-2 h: 507 +/- 83 dynes * sec * cm(-5)). Oxygenation after 2 h of ischemia and 30 min reperfusion was significantly better in the LPEC group compared to EC and controls (L PEC: 70 +/- 17 mmHE, EC: 44 +/- 3 mmHg). The wet/dry ratio was signifi cantly lower in the two preserved groups compared to controls (LPEC-5 min: 5.7 +/- 0.7, EC-5 min: 5.8 +/- 1.2, controls-5 min: 7.5 +/- 1.8, LPEC-2 h: 6.7 +/- 0.4, EC: 6.9 +/- 0.4, controls-2 h: 7.3 +/- 0.4).Con clusions. We thus conclude that LPEC results in better oxygenation and lower PVR in this lung preservation model. A low potassium concentrat ion in lung preservation solutions may help in reducing the incidence of early graft dysfunction following lung transplantation.