α-Adrenergic blockade in preventing posttransplant edema of lung allograft

Effect of α-adrenergic blockers on pulmonary edema in lung transplantation was studied with a rat model of syngeneic left lung transplantation. Prior to harvesting, 0.1 mg of Prazocin or 0.4 mg of Yohimbin was given to the donor. Pulmonary and systemic hemodynamics were measured under the right pulmonary arterial occlusion (RPAO) at different time points after grafting. Wet to dry weight ratio (W/D) of all transplants was also calculated. Same procedure was conducted in rats with normal and ischemic lung and in transplanted animals without any treatments. While RPAO did not increase W/D in normal lung with a significant elevation in pulmonary arterial pressure (PAP), both these values significantly increased in transplanted lung. Transplanted animals could not tolerate RPAO 24 hours after grafting, but were tolerable later than 48 hours with elevated W/D and PAP. On the contrary, animals given Prazocin or Yohimbin were all tolerable at 24 hours postsurgery. Yohimbin significantly improved W/D. Consequently, it was demonstrated that pulmonary edema of the graft reached its peak during first 24 to 48 hours after transplantation and was alleviated by the blockade of α-adrenergic receptor in the graft vessel. (C) 1999 Tohoku University Medical Press.