Lung transplantation is a complex procedure performed in patients with terminal lung disease. The transplant procedure stresses the patient's heart and lungs, which are already taxed by the underlying disease process. The heart-lung machine is occasionally used to support the patient and ensure adequate oxygen supply to other organs during the operation. It can be used routinely in all patients or selectively in patients who exhibit reduced oxygen supply to the remaining organs. This process, known as cardiopulmonary bypass (CPB), pumps blood out of the body to a heart-lung machine that removes carbon dioxide and returns oxygen-filled blood to the body.

Although using the CPB increases the risk of bleeding, infection, and coagulation complications, it should still be considered in high-risk patients to compensate for more severe complications such as kidney failure and stroke caused by a lack of cardiopulmonary support. Extracorporeal membrane oxygenation (ECMO) is a recently developed CPB variation associated with fewer bleeding complications. It has recently replaced the traditional heart-lung machine as the preferred method of cardiopulmonary support during lung transplantation. Since ECMO is associated with fewer complications than standard CPB, many centers have increased their use of ECMO during lung transplantation. Some have even employed it routinely. However, there remains significant debate on how often it should be used.

Therefore, the study's main objective is to compare the two approaches in lung transplantation, i.e., routine use versus selective use, and to determine if one approach is preferable to the other.

This study compares two approaches to intraoperative cardiopulmonary support during lung transplantation: routine cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) versus selective use. Despite recent improvements in lung transplant outcomes, postoperative complications are common. Intraoperative hemodynamic management is vital to the success of lung transplantation. Many centers, including all four Canadian centers, use ECMO to provide intraoperative support. However, lung transplantation without cardiopulmonary support may be possible in certain patients. In such patients, the transplant may be started without ECMO. ECMO may be initiated "on-demand" if hemodynamic embarrassment or hypoxia occurs. Conversely, the opposite approach would be routinely conducting all lung transplants using ECMO. The current practice in many centers is to use ECMO selectively. By extension, the investigators believe that more liberal use of intraoperative ECMO will produce less intraoperative hemodynamic instability and hypoxia. However, it is unclear the extent of ECMO use necessary to improve the incidence of postoperative hypoperfusion-related complications. Should ECMO be used routinely in all patients or selectively based on the intraoperative course? The study is a prospective, randomized, controlled trial with two treatment arms: routine support with ECMO versus selective (on-demand) support with ECMO. Study population (Inclusion and exclusion criteria): All patients, 18 years of age or older, undergoing lung transplantation will be screened for participation. We will exclude patients who require intraoperative ECMO, multi-organ transplants, and retransplantation Arms and Interventions: On-demand ECMO: The transplant will be planned without cardiopulmonary support in this group. Intraoperative ECMO will be employed if there is an inability to maintain adequate organ perfusion and oxygen delivery despite resuscitation. Routine ECMO: Routine intraoperative ECMO in all patients, regardless of hemodynamic status. Primary outcome: Intensive care unit (ICU)-free days in the first 28 days post-lung transplant.

Inclusion Criteria:

• Patients undergoing lung transplant surgery

Exclusion Criteria:

• Inability to provide consent for the study

• Retransplantation

• Multi-organ transplantation

• Contra-indication to standard heparin anticoagulation (e.g., heparin-induced thrombocytopenia)

• Lung transplant recipients where intraoperative cardiopulmonary support is mandatory:

• Severe pulmonary hypertension (PH):

  1. Systolic pulmonary artery pressure (PAP) ≥ 80 mm Hg on the most recent echocardiography, right heart catheterization, or pulmonary artery catheter measurement
  2. Mean PAP ≥ 55 mm Hg on the most recent echocardiography, right heart catheterization, or pulmonary artery catheter measurement
  3. The ratio of mean pulmonary to systemic artery pressure of > 0.66

• Moderate to severe right ventricular (RV) hypokinesis or dysfunction

• Left ventricular dysfunction: Defined as ejection fraction (LVEF) less than 45% on echocardiography, ventriculography, computed tomography (CT), or magnetic resonance imaging (MRI)

• Patients requiring concomitant cardiac surgery: For example, significant coronary artery disease (CAD) requiring surgical grafting