Single-lung allotransplantation in pigs: effects of two preservation methods on pulmonary gas exchange.

Single left lung allotransplantation was performed in 16 pigs to determine an optimal solution for lung preservation. Modified Euro-Collins and oxygenated fluorocarbon solutions (FC-43) were used as the lung preservative. Donors in both groups were pretreated with intravenous prostaglandin E1 infusions. The effects of the two different preservatives on ventilation and oxygenation were noninvasively monitored with capnometry and pulse oximetry. The functional results were further compared with morphologic findings. After implantation the right pulmonary artery was clamped, and the transplanted lung supported pulmonary circulation and ventilation. Arterial carbon dioxide tension (PaCO2) and arterial oxygen tension (PaO2) were measured from the arterial blood samples. The Euro-Collins group experienced hypercarbia (PaCO2, 54 to 72 mm Hg) and low end-tidal carbon dioxide (EtCO2) values (3.3% to 3.9%) when the donor lung was reimplanted and reperfused. The pigs in the Euro-Collins group were also hypoxemic after reimplantation of the left lung. The saturation (SpO2) values were 85% to 89%, and the PaO2 values were between 61 and 66 mm Hg. The oxygenated fluorocarbon group had normal ventilatory parameters and arterial oxygen saturation after reimplantation of the left lung; no significant gradient between EtCO2 and PaCO2 was detected. Scanning and transmission electron-microscopic studies of the transplanted lungs showed good to moderate preservation after reperfusion in the oxygenated fluorocarbon group, whereas preservation was judged to be moderate in the Euro-Collins group. Oxygenated fluorocarbon (FC-43) donor lung preservation thus resulted in superior functional recovery in pulmonary gas exchange during reperfusion compared with Euro-Collins solution. Electron-microscopic findings supported functional results obtained.