Oxygenated blood perfusion provides no additional benefit beyond flow control in lung ischemia-reperfusion injury

Primary graft dysfunction, largely caused by ischemia-reperfusion injury (IRI), remains a major determinant of outcomes after lung transplantation. While protective perfusion, achieved by reducing perfusion pressure and flow, has been shown to mitigate lung IRI, the effect of oxygenated blood perfusion remains unclear. We developed an in vivo model using extracorporeal membrane oxygenation (ECMO) to control perfusion pressure and oxygen tension in perfusion blood of ischemic lungs and evaluated its potential protective effects against lung IRI.

A porcine IRI model was established by clamping the left pulmonary hilum for 2.5 h. After reperfusion, animals were assigned to three groups: the control group, which received only lung rest ventilation; the veno-arterial ECMO (VA-ECMO) group; and the combined veno-arterial and veno-pulmonary artery ECMO (cVPA-ECMO) group, in which oxygenated blood was additionally delivered into the left pulmonary artery (PA). Each group underwent a 4-h intervention period followed by a 4-h observation phase.

Both ECMO groups showed improvements in pulmonary function, hemodynamics, tissue injury, edema, cell death, and inflammatory markers compared with controls, suggesting attenuation of IRI. However, no significant differences were found between the VA-ECMO and cVPA-ECMO groups in any evaluated parameter, and no clear additive benefit from oxygenated blood delivery to the PA was observed.

In lung IRI, oxygenated blood perfusion showed no additive benefit beyond the protective effect of flow control. These findings suggest that ventilation-based oxygenation and hemodynamic management play a greater role in attenuating IRI.