Twelve Hour Perfusion of Isolated Pulmonary Lobes

¹ Department of Surgery, Division of Cardiovascular and Thoracic Surgery, and the Surgical-Medical Research Institute, The University of Alberta, Edmonton, Alberta, Canada
² Professor of Surgery, The University of Alberta

Most studies with isolated canine lungs describe early functional deterioration after three to six hours of perfusion. Our techniques permit routine preservation of function and morphology in isolated pulmonary lobes for over 12 hours. Eight pulmonary lobes were perfused with heparinized blood inside a specially constructed chamber designed to maintain negative pressure ventilation, physiologic flow rates and normal venous pressures. Incorporation of the donor animals into the circuit provided a convenient means of deoxygenation and maintained the normal metabolic environment. All lobes were perfused from 12 to 18 hours before deterioration of the donor animal terminated each experiment. Pulmonary vascular resistance rose slowly and compliance diminished gradually in each case. The mean veno-arterial oxygen gradient after 12 hours of perfusion was 55 mm Hg and the mean weight gain was 31 percent. Representative sections of perfused lobes revealed mild interstitial edema and leukocytic infiltration with more extensive changes in the nonperfused lobes from the donor animals subjected to prolonged positive pressure ventilation. Prolonged function of perfused lobes was attributed to simulation of the normal intrathoracic ventilation perfusion dynamics.