Abstract
Fifty-one rabbit heart-lung blocks were used in this investigation of the effect of calcium blockers on lung preservation. The lungs were inflated with room air and preserved by simple surface cooling for 18 hours. Graft function was assessed by non-recirculated perfusion with autologous blood. Five of the 51 rabbits were used for in vivo control values. Six of the 51 grafts were preserved at 4°C without a calcium blocker (control group 1), and another six grafts (control group 2) were preserved at 8°C without a calcium blocker. Functional indexes, such as pulmonary infusion pressure (PAP), effluent oxygen tension (pO2), and wet-dry weight ratio of perfused lung (W/D) were significantly worse in control proup 1 than in control goup 2. Diltiazem chloride and nicardipine chloride were tested. Thirty-four grafts preserved at 4°C were classified into three groups according to the method of administration of calcium blocker. In vivo group 1 (n=12) recceived calcium blocker intravenously before thoracotomy. In vivo group 2 (n=16) received calcium blocker into the right atrium immediately after exanguination. Ex vivo group (n= 6) : calcium blocker was administered in the blood reperfused for assesment of graft function. PAP and pO2 levels, but not W/D, in in vivo groups 1 and 2 were close to those of control group 2. Graft function in in vivo groups 1 and 2 was significantly better than that in control group 1 or the ex vivo group.
Our results show that calcium blockers prevent the deterioration of grafts preserved at 4°C and suggest that intracellular calcium flux related to the calcium paradox might occur even in the pulmonary artery during lung preservation.
