Canine double-lung transplantation with cadaveric donors

Abstract

If lungs could be retrieved from cadavers after circulatory arrest, the critical shortage of donors for lung transplantation might be alleviated. To assess gas exchange after transplantation of lungs from cadaveric donors, we performed double-lung transplantation through sequential thoracotomies in 12 dogs. Donors were sacrificed by intravenous pentobarbital injection and then ventilated with 100% oxygen. Lungs were harvested 2 hours ( n = 6) or 4 hours ( n = 6) after death and flushed with 2 L modified Euro-Collins solution. Recipients underwent sequential right and left lung transplantation; they were then monitored while under anesthesia for 8 hours, with adjustments of the fraction of inspired oxygen. Nine of 12 recipients survived the 8-hour study period. Four of six dogs with cadaveric lungs retrieved 2 hours after death survived; deaths were from pulmonary embolism at 6 hours and pulmonary edema at 2 hours. Five of six dogs with cadaveric lungs retrieved 4 hours after death survived; one died of hypoxia during implantation of the left lung, while dependent on the right lung graft. Postoperative hemodynamic and gas exchange parameters were similar in both groups. Alveolar-arterial oxygen gradient rose significantly compared with baseline 1 hour after transplantation in both groups (462 ± 60 vs 38 ± 31 mm Hg for 2-hour group, p < 0.0001, and 484 ± 63 vs 38 ± 14 mm Hg for 4-hour group, p < 0.0002). By 8 hours after operation, the gradients had significantly decreased in both groups (105 ± 37 mm Hg for 2-hour group and 146 ± 53 mm Hg for 4-hour group) and were similar to baseline values. Extravascular lung water also rose significantly 1 hour after transplantation (15.7 ± 2.8 vs 7.9 ± 0.5 ml/kg for 2-hour group, p < 0.02, and 16.9 ± 1.2 vs 6.6 ± 0.4 ml/kg for 4-hour group, p < 0.0001) and decreased gradually during the 8-hour study period. Donor lungs retrieved at 2 and 4 hours postmortem afford similar recipient outcomes. Improvement in alveolar-arterial oxygen gradient and reduction in extravascular lung water during the study period imply that the ischemia-reperfusion injury induced by this model is reversible. If this approach could be safely introduced to clinical practice, substantially more transplant procedures could be performed. (J T HORAC C ARDIOVASC S URG 1996;112:577-83)