Consensus on the use of extracorporeal membrane oxygenation during the perioperative period of lung transplantation

Lung transplantation is an effective treatment for end-stage lung disease, with the number of transplants steadily increasing and short-term survival rates improving;^[1] however, the increasing complexity of recipient conditions makes perioperative management more challenging. Serious complications, such as cardiopulmonary dysfunction, can significantly affect prognosis. Extracorporeal membrane oxygenation (ECMO) plays a critical role throughout the perioperative period. Preoperatively, it serves as a bridge for patients with severe respiratory or circulatory failure; intraoperatively, it maintains hemodynamic stability and adequate oxygenation; and postoperatively, it is used to manage complications such as primary graft dysfunction (PGD), rejection, infection, or cardiac failure. Globally, intraoperative ECMO is used in approximately 29% of lung transplantations. In China, data from 2022 show that 5.9% of patients received preoperative ECMO, and 77.6% received intraoperative ECMO, predominantly in the venovenous (VV) (61.1%) or venoarterial (VA) (33.6%) mode.^[2] Despite its widespread use, standardized perioperative ECMO protocols are lacking.

This consensus, registered on the PREPARE platform (PREPARE-2024CN362), was developed by a multidisciplinary panel of more than 40 experts in lung transplantation, critical care, anesthesiology, and nursing. All the members reported no conflicts of interest. Fourteen key clinical questions were identified using structured surveys. A systematic literature review from January 2000 to December 2024 was conducted using the which stands for Population, Intervention, Comparison, and Outcome (PICO) framework. Two reviewers independently screened the studies; disagreements were resolved through discussion or consultation with a third reviewer. The quality of evidence and strength of the recommendations were graded according to the 2009 Oxford Centre for Evidence-Based Medicine criteria. Recommendations were formulated through iterative discussion, voting, and external review, incorporating evidence quality, clinical feasibility, and benefit-risk balance.

QUESTION 1: What are the recommendations for the establishment of a multidisciplinary treatment team (MDT) and an ECMO team in lung transplantation?

Recommendation 1: A structured ECMO team with defined roles is recommended to ensure efficient coordination. (Grade B, Level 2c)

With increasing procedural complexity, lung transplantation has transitioned from a single-specialty model to a patient-centered multidisciplinary approach. Surgeons, anesthesiologists, and intensivists jointly participate in evaluation, perioperative planning, and management. This approach improves risk stratification and clinical decision-making.

A dedicated ECMO team should include a team leader, coordinators, ECMO specialists, and equipment and data managers. Regular training, simulation, and competency assessment are essential to ensure rapid response capability and procedural safety.^[3]

QUESTION 2: Which patients are suitable for preoperative ECMO bridging therapy?

Recommendation 2: ECMO bridging is recommended for candidates with progressive respiratory and/or hemodynamic deterioration refractory to conventional therapy. (Grade B, Level 2a)

Recommendation 3: ECMO may be used in newly referred patients with acute cardiopulmonary failure who are dependent on ECMO and for whom transplantation is the only viable option. (Grade B, Level 2c)

Candidates include patients already listed or under evaluation who deteriorate while waiting as well as patients already receiving ECMO who cannot be weaned because of irreversible respiratory failure.^[4-5] Bridge ECMO may be continued intraoperatively or adjusted depending on clinical status (Figure 1).

Figure 1. Preoperative ECMO bridging flowchart for lung transplant recipients. ECCO₂R: Extracorporeal carbon dioxide removal; VV: venovenous; VA: venoarterial; ECMO: extracorporeal membrane oxygenation.

QUESTION 3: What are the indications and implementation strategies for awake ECMO?

Recommendation 4: Awake ECMO may be considered for patients who are conscious and have stable hemodynamics, preserved respiratory drive, and adequate airway protection reflexes. (Grade B, Level 2b)

Recommendation 5: For patients receiving awake ECMO, hemodynamics and respiratory function need to be closely monitored, and early mobilization and/or rehabilitation should be encouraged based on the patient’s tolerance. (Grade B, Level 2b)

Awake ECMO allows spontaneous breathing without intubation, thus reducing ventilator-associated complications, sedation requirements, and delirium. It preserves muscle strength and facilitates rehabilitation.

Rehabilitation should be progressive, from passive to active mobilization, under multidisciplinary supervision.^[6] Therapy must be individualized based on the cannulation site, lung compliance, anticoagulation status, and underlying diseases. Low-dose sedatives may be used if necessary, and complications should be closely monitored.^[7]

QUESTION 4: How should the ECMO mode be selected for preoperative bridging?

Recommendation 6: For hemodynamically stable patients with hypoxemia and/or hypercapnia without right heart failure, VV ECMO is recommended as a first-line transitional strategy. (Grade B, Level 2b)

Recommendation 7: For patients with end-stage lung disease complicated by pulmonary hypertension and right heart failure, resulting in severe hemodynamic instability and respiratory failure, VA ECMO or veno-arteriovenous (V-AV) ECMO is recommended. ^[8] (Grade B, Level 2b)

Recommendation 8: For patients with hypercapnic respiratory failure, extracorporeal CO₂ removal (ECCO₂R) may be considered. ^[9] (Grade B, Level 2c)

QUESTION 5: What are the key management strategies for prolonged preoperative ECMO?

Recommendation 9: In prolonged preoperative ECMO support, management should focus on the prevention and treatment of complications. (Grade B, Level 2b)

Although the duration of ECMO does not directly affect survival, prolonged support increases the risk of complications.^[10] Key concerns include infection, bleeding, thrombosis, limb ischemia, malnutrition, and muscle wasting. Management strategies include strict infection control, optimized anticoagulation (target activated partial thromboplastin time [APTT] 40-55 s),^[11] nutritional support, and regular assessment of cardiopulmonary and functional status. Individualized care and multidisciplinary coordination are essential.

QUESTION 6: What extracorporeal life support strategies are available during lung transplantation?

Recommendation 10: For patients requiring extracorporeal life support during surgery, ECMO is recommended as an alternative to cardiopulmonary bypass (CPB) surgery. (Grade B, Level 2b)

Recommendation 11: For patients undergoing peripheral VV ECMO, if hypoxemia, secondary heart failure, or lobar transplantation occurs during the procedure, conversion to centrally cannulated V-AV ECMO or venovenous-arterial (VV-A) ECMO may be considered. At the end of surgery, blood flow can be gradually reduced, and the mode can be switched to peripheral VV ECMO, VA ECMO, or peripheral V-AV ECMO. (Grade C, Level 4)

Recommendation 12: In patients receiving VA ECMO who develop differential hypoxemia, conversion to peripheral V-AV ECMO may be considered. (Grade C, Level 4)

Recommendation 13: When combined cardiac procedures are performed, CPB may be considered. After cardiac surgery, once heart function recovers, CPB can be switched to central cannulation ECMO, and after lung transplantation, it can be transitioned to peripheral ECMO. (Grade B, Level 2c)

Compared with CPB, ECMO is associated with lower rates of graft dysfunction, fewer transfusion requirements, and better outcomes.^[12] However, ECMO mode adjustments may be necessary intraoperatively in response to hypoxemia or hemodynamic instability (Figure 2). ^[13,14]

Figure 2. Intraoperative and postoperative ECMO for lung transplant recipients. ECMO: extracorporeal membrane oxygenation; BTT: bridge to transplantation; CPB: cardiopulmonary bypass; TEE: transesophageal echocardiography; PGD: primary graft dysfunction.

QUESTION 7: What are the key management considerations for intraoperative ECMO during lung transplantation?

Recommendation 14: Multimodal monitoring, including Swan-Ganz catheterization, transesophageal echocardiography (TEE), and blood gas analysis, is recommended. (Grade B, Level 2c)

Recommendation 15: Stable ECMO flow should be maintained and adjusted according to intraoperative conditions. (Grade C, Level 4)

ECMO flow is maintained at 50-80 mL/(kg·min), with venous oxygen saturation (SvO₂) > 70%.^[15] Continuous monitoring is required during surgical manipulation, including cannula positioning and pulmonary artery clamping, to ensure adequate oxygen delivery and hemodynamic stability.

QUESTION 8: What are the indications for ECMO weaning in the operating room after lung transplantation?

Recommendation 16: ECMO weaning is suggested when hemodynamics as well as gas exchange are stable and when no major complications are present. (Grade B, Level 3b)

Recommendation 17: If hemodynamic instability persists or if oxygenation is insufficient because of pulmonary edema, continued ECMO use or transition from central ECMO to peripheral ECMO is recommended. (Grade B, Level 2a)

Weaning criteria included stable hemodynamics, satisfactory oxygenation, absence of bleeding or graft dysfunction, and adequate cardiac function. ECMO flow should be gradually reduced under close monitoring. VA ECMO is maintained if hemodynamic instability or cardiac dysfunction persists, whereas VV ECMO supports patients with hypoxemia. ^[16] Severe primary transplant dysfunction remains a leading cause of early mortality (15%-25%). ECMO provides effective support, and early or continued use, particularly VV ECMO, improves graft recovery and patient survival.^[17]

QUESTION 9: What are the indications for weaning from ECMO after lung transplantation?

Recommendation 18: For patients with stable hemodynamics and good oxygenation, weaning from ECMO is recommended after a comprehensive assessment of cardiopulmonary function. (Grade B, Level 2b)

With respect to VV ECMO, flow and sweep gas are gradually reduced. Successful weaning requires stable blood gases and imaging improvement.^[18] For VA ECMO, cardiac function must also be assessed, including echocardiographic parameters and hemodynamic stability. ^[19]

QUESTION 10: What are the indications and key points for initiating ECMO after lung transplantation?

Recommendation 19: In the early postoperative period, ECMO is suggested for lung transplant recipients who develop rapid elevation in pulmonary artery pressure, severe pulmonary edema, right heart dysfunction, or severe hypoxemia that continues to worsen despite routine treatment and in the absence of contraindications. (Grade B, Level 3b)

Recommendation 20: When PGD manifests mainly as isolated respiratory failure (refractory hypoxemia or hypercapnia) and hemodynamic stability is maintained, VV ECMO is recommended as the first-line support method. (Grade A, Level 2b)

Recommendation 21: For recipients receiving ECMO support who fail to show early improvement in graft function, re-transplantation may be considered following MDT discussion. (Grade B, Level 2c)

Recommendation 22: In severe cases of PGD, TEE is suggested to rule out reversible causes such as left ventricular dysfunction, intracardiac shunt, pulmonary vein anastomosis stenosis, or thrombosis. (Grade B, Level 3)

Early acute respiratory failure after lung transplantation can be caused by PGD, acute heart failure in patients with pulmonary hypertension, pleural effusion, infection, acute rejection, or anastomotic complications (such as hypoxemia, acidosis, increased pulmonary artery pressure, and decreased lung compliance).^[20] VV ECMO is preferred for patients with isolated respiratory failure. Early intervention improves graft recovery and survival. Reversible causes of graft dysfunction should be excluded using TEE before prolonged ECMO support. ^[21]

QUESTION 11: What are the specific considerations for ECMO in lung transplant recipients with pulmonary hypertension?

Recommendation 23: In patients with severe pulmonary hypertension, awake ECMO may be considered prior to anesthesia induction to maintain hemodynamic stability. (Grade D, Level 5)

Recommendation 24: In patients with moderate-to-severe secondary pulmonary hypertension, peripheral or central VA ECMO is preferred intraoperatively based on preoperative cardiac function. (Grade B, Level 2a)

Recommendation 25: In patients with pulmonary hypertension, postoperative cardiac function and pulmonary artery pressure should be closely monitored, and prolonged VA ECMO support is suggested when appropriate to facilitate cardiac recovery. (Grade B, Level 2b)

“Awake ECMO” performed before anesthesia induction is a preventive strategy that provides immediate cardiopulmonary support, maintains systemic pressure as well as coronary perfusion, and prevents circulatory failure.^[22] The pulmonary artery pressure above 50 mmHg (1 mmHg=0.133 kPa) usually indicates the need for ECMO. Postoperatively, delayed weaning from VA ECMO helps reduce ischemia-reperfusion injury, modulate pulmonary vascular resistance, support right ventricular recovery, and reduce the risk of severe PGD, especially during the first 72 h, when the transplanted lung is highly sensitive to changes in left atrial pressure. ^[23]

QUESTION 12: What are key points for VV ECMO double-lumen catheter placement?

Recommendation 26: Double-lumen catheter (DLC) placement can be used for awake bridging before lung transplantation, with the right internal jugular vein being the most common site. (Grade B, Level 3)

Recommendation 27: DLC placement should be guided by imaging, such as TEE or X-ray, to ensure correct positioning. (Grade B, Level 3)

Double-lumen cannulation reduces complications, improves mobility, and facilitates awake ECMO. Accurate positioning is critical and requires imaging guidance. ^[24]

QUESTION 13: What are the anticoagulation strategies for ECMO during the perioperative period of lung transplantation?

Recommendation 28: Systemic anticoagulation should be initiated at the time of ECMO cannulation with unfractionated heparin as the preferred agent at an initial dose of 50-100 U/kg. In cases requiring immediate surgery, low-dose anticoagulation or heparin-free anticoagulation may be suggested. (Grade B, Level 2b)

Recommendation 29: Intraoperatively, monitoring coagulation parameters, including activated clotting time (ACT), APTT, and thromboelastography (TEG), may be suggested to guide anticoagulation dosing. (Grade B, Level 2c)

Recommendation 30: In patients with extensive adhesions and high bleeding risk, a reduction in heparin dosage is suggested. (Grade B, Level 2b)

Recommendation 31: In patients receiving perioperative ECMO support, close monitoring of oxygenation and thrombotic complications is suggested during blood product transfusion. (Grade B, Level 2b)

Most ECMO circuits are coated with heparin, but systemic heparinization (50-100 U/kg) is still recommended, with monitoring via ACT, APTT, or TEG. ^[25] VV ECMO requires a lower dose of anticoagulation. Some patients may tolerate very little or no heparin if blood flow is adequately maintained, especially in the presence of severe adhesions or coagulation disorders, but circuit thrombosis must be closely monitored. VA ECMO can use low-dose heparin without increasing the risk of thrombosis and can reduce postoperative bleeding. Blood product infusions during ECMO can significantly alter coagulation function, potentially leading to a hypercoagulable state and membrane thrombosis or exacerbating coagulation factor depletion and bleeding.^[26] Continuous assessment is needed to balance bleeding and thrombosis.

QUESTION 14: What are the strategies for the prevention and management of bleeding, thrombosis, and limb ischemia during ECMO support in lung transplantation?

Recommendation 32: Rapid-response protocols for acute bleeding could be developed to quickly identify the cause of bleeding and intervene in a timely manner. (Grade C, Level 3)

Recommendation 33: Pulmonary vascular thrombosis may be an underlying cause of unexplained graft dysfunction after transplantation. (Grade B, Level 2b)

Recommendation 34: To prevent limb ischemia, the placement of a distal perfusion catheter in the superficial femoral artery using a smaller cannula is suggested to ensure adequate reperfusion. (Grade B, Level 2b)

Postoperative active bleeding requires rapid multidisciplinary evaluation to differentiate between surgical and coagulation-related causes, to determine the bleeding site, and to monitor coagulation function. ACT targets may be lowered (e.g., 170-190 s), heparin use may be discontinued, and blood flow may be maintained at >3 L/min. Blood products may be transfused based on TEG, rotational thromboelastography (ROTEM), or coagulation factor assay results.^[27] Thrombosis is also common because of hypercoagulable states, nonendothelialized circuits, and turbulent flow. Monitoring includes visual inspection, interface checks, oxygenator pressure gradients, and D-dimer levels. Large oxygenator thrombosis with hemolysis may require circuit replacement. Pulmonary embolism should be suspected in cases of unexplained hypoxemia, decreased compliance, or instability and evaluated with bedside echocardiography or computed tomography pulmonary angiogram (CTPA).^[28] Limb ischemia can be caused by cannula size, obstruction, low flow, vasoconstriction, or venous congestion; routine limb monitoring and early distal perfusion cannulation are crucial for prevention.^[29]

Founding: The study was supported by National Key R&D Program of China (2023YFC2507100).

Ethical approval: Not needed.

Conflicts of interest: The authors declare that they have no competing interests.

Contributors: All the authors participated in the drafting, critical revision, and approval of the final version of the manuscript.