Routine Versus Selective Intraoperative ECMO in Lung Transplant

Intraoperative hemodynamic management is vital in the success of lung transplantation. Significant intraoperative hemodynamic compromise and hypoxic episodes may contribute to an increase in severe postoperative complications related to hypoperfusion, including cerebrovascular accidents, acute kidney injury, and mesenteric ischemia. In certain lung transplant recipients, intraoperative cardiopulmonary support is mandatory because certain factors would make "off-pump" transplants unsafe. These include severe pulmonary hypertension or severe ventricular dysfunction. In such patients, routine intraoperative support should be employed. However, it is possible to conduct the lung transplant without cardiopulmonary support in the remainder of patients who do not have severe pulmonary hypertension or right heart dysfunction. In such patients, the lung transplant may be started without cardiopulmonary support. However, cardiopulmonary support may be initiated "on-demand" if there is development or impending hemodynamic embarrassment or hypoxia. Conversely, the opposite approach would be to routinely conduct all lung transplant operations using cardiopulmonary support, which may also lead to specific ECMO-related complications.

The investigators question whether on demand intraoperative ECMO in patients with significant risk factors will produce severe postoperative complications in a rate similar to routine ECMO.

Hypothesis: In patients where cardiopulmonary bypass (CPB) / ECMO is not mandatory, on-demand use of intra-operative ECMO is equivalent to routine use for patients undergoing lung transplant.

The study will be a prospective, randomized controlled trial. The investigators seek to compare outcomes of two different strategies of cardiopulmonary support during lung transplantation; routine support with ECMO versus selective (on-demand), indication- based support with ECMO. The allocation ratio will be 1:1. A multi-center trial is necessary to allow for a sufficient sample size. However, the investigators believe a pilot study is essential to determine feasibility before embarking on such a significant undertaking.

In this preliminary pilot study, recruitment will be limited to lung transplant patients at the Centre hospitalier de l'Universite de Montreal (CHUM). The primary purpose of the pilot study will be to define recruitment ability and assess the feasibility of conducting the study. Depending on the results of this pilot study, the next step would be to expand the study to multiple lung transplant centers to achieve an adequate sample size and power, allowing the investigators to answer the question of interest.

Eligibility Criteria:
Inclusion Criteria:

Patients undergoing lung transplant surgery during the study period (6 months)

Exclusion Criteria:

1. Inability to provide consent for the study or patient refusal
2. Retransplantation
3. Multi-organ transplantation
4. Lung transplant recipients where intraoperative support is mandatory and "off- pump" transplant would be unsafe:

   a. Severe pulmonary hypertension (PH):

   i. Systolic pulmonary artery pressure (PAP) ≥ 80 mm Hg on echocardiography, right heart catheterization, or pulmonary artery catheter measurement

   ii. Mean PAP ≥ 55 mm Hg on echocardiography, right heart catheterization, or pulmonary artery catheter measurement

   iii. The ratio of mean pulmonary to systemic artery pressure of more than 0.66

   b. Moderate to severe right ventricular (RV) hypokinesis or dysfunction

   c. Left ventricular dysfunction: Defined as ejection fraction (LVEF) \< 50% on echocardiography, ventriculography, computed tomography (CT), or magnetic resonance imaging (MRI)

   d. Significant coronary artery disease (CAD)requiring stenting or surgical grafting