The protective effect of hypercapnia on ischemia-reperfusion injury in lungs

Lifesaving therapy for patients with end-stage lung disease is lung transplantation. However, there are not enough available donors. A relatively new method of transplantation from non-heart-beating donors (NHBDs) allows the treatment of the lung outside the body and could increase the number of suitable lungs. We have focused on hypercapnic ventilation, which has the possibility of reducing reactive oxygen species damage. We used four experimental and two control groups of adult rats. Each experimental group underwent the protocol of NHBD lung harvesting. The lungs were than perfused in an ex vivo model and we measured weight gain, arterial-venous difference in partial pressure of oxygen and perfusion pressure. We observed that hypercapnic ventilation during reperfusion reduces the development of pulmonary oedema and has a protective effect on the oxygen transport ability of the lungs after warm ischemia. The effect of CO2 on pulmonary oedema and on oxygen transport ability after warm ischemia could be of clinical importance for NHBD transplantation.