ECMO in Cardiac Surgery: When and How to Implement It

Introduction

Extracorporeal Membrane Oxygenation (ECMO) has become a vital intervention in cardiac surgery, offering temporary mechanical support for patients experiencing severe cardiac dysfunction. It stabilizes hemodynamics, allowing time for myocardial recovery or serving as a bridge to more definitive treatments (Bartlett et al., 2020). This article explores the indications for ECMO use in cardiac surgery, initiation protocols, cannulation strategies, management considerations, and potential complications.

1. Indications for ECMO in Cardiac Surgery

ECMO is primarily indicated when conventional therapies fail to maintain adequate cardiac output and tissue perfusion. Key indications include:

• Post-cardiotomy cardiogenic shock – Patients unable to wean from cardiopulmonary bypass due to ventricular dysfunction may benefit from ECMO support to restore hemodynamic stability (El Sibai et al., 2018).
• Acute myocardial infarction (MI) with cardiogenic shock – ECMO can provide circulatory support in acute MI cases complicated by cardiogenic shock, improving in-hospital survival and reducing 30-day mortality when used alongside revascularization (Ouweneel et al., 2016).
• Fulminant myocarditis – In cases of severe myocardial inflammation leading to rapid deterioration, ECMO serves as a bridge to recovery, offering time for the myocardium to heal (Lorusso et al., 2021).
• Refractory ventricular arrhythmias – For arrhythmias unresponsive to medical management, ECMO can stabilize the patient while addressing the underlying cause (Bailly et al., 2020).
• Massive pulmonary embolism with right heart failure – ECMO provides circulatory support in massive pulmonary embolism cases complicated by right heart failure, serving as a bridge to more definitive treatments like thrombectomy (Grewal et al., 2022).

2. Initiating ECMO in the Operating Room vs. Intensive Care Unit (ICU)

The decision to initiate ECMO in the operating room (OR) or ICU depends on the patient’s condition:

• Intraoperative initiation – Patients exhibiting severe ventricular dysfunction or inability to wean from cardiopulmonary bypass during surgery may require immediate ECMO support in the OR to stabilize hemodynamics (Pappalardo et al., 2019).
• Postoperative initiation – Patients developing cardiogenic shock or other complications in the ICU post-surgery may necessitate ECMO to manage deteriorating cardiac function (Takayama et al., 2020).

3. Key Considerations for ECMO Cannulation

Selecting the appropriate cannulation strategy is vital for effective ECMO support:

• Peripheral cannulation – Involves inserting cannulas into peripheral vessels, such as the femoral artery and vein. This approach is less invasive and can be performed bedside but carries risks like limb ischemia (Malik et al., 2018).
• Central cannulation – Entails direct cannulation of central vessels, typically during surgery. While offering better hemodynamic support, it requires a sternotomy and is more invasive (Al-Fares et al., 2020).

4. Managing ECMO Support in Cardiac Surgery Patients

Effective management strategies include:

• Optimizing perfusion parameters – Adjusting ECMO flow rates to ensure adequate tissue perfusion and oxygen delivery (Lorusso et al., 2021).
• Anticoagulation management – Balancing the risk of thrombosis with bleeding by monitoring coagulation parameters and tailoring anticoagulant therapy accordingly (Bailly et al., 2020).
• Monitoring cardiac recovery – Regular assessment of myocardial function through imaging and hemodynamic monitoring to determine readiness for weaning from ECMO (Grewal et al., 2022).
• Weaning strategies – Gradual reduction of ECMO support while closely monitoring cardiac performance to ensure stability before decannulation (Takayama et al., 2020).

5. ECMO Complications and Prevention

Potential complications and preventive measures include:

• Bleeding and thrombosis – Regular monitoring of coagulation status and meticulous management of anticoagulation therapy are essential to prevent hemorrhagic or thrombotic events (Malik et al., 2018).
• Limb ischemia – Particularly relevant in peripheral cannulation; preventive strategies involve vigilant monitoring and timely intervention to mitigate ischemic complications (El Sibai et al., 2018).
• Infection – Strict aseptic techniques during cannulation and maintenance can reduce the risk of infections associated with ECMO (Al-Fares et al., 2020).

Conclusion

ECMO serves as a critical intervention in cardiac surgery, offering life-sustaining support in severe cardiac dysfunction cases. A multidisciplinary approach, encompassing timely initiation, appropriate cannulation strategies, meticulous management, and vigilant monitoring for complications, is essential to optimize patient outcomes. As technology and clinical experience advance, the role of ECMO in cardiac surgery continues to evolve, promising improved survival and recovery for critically ill patients.

References

• Al-Fares, A., Pettenuzzo, T., Del Sorbo, L. and Fan, E. (2020) ‘Extracorporeal Life Support and Systemic Inflammation’, Intensive Care Medicine, 46(4), pp. 819–830.
• Bailly, D.K., King, C.S. and Sobhanie, M. (2020) ‘Venoarterial ECMO for Refractory Ventricular Arrhythmias: A Case Series’, ASAIO Journal, 66(6), pp. e97–e100.
• Bartlett, R.H., Ogino, M.T., Brodie, D. et al. (2020) ‘Clinical Guidelines for Adult ECMO’, Annals of Thoracic Surgery, 109(3), pp. 999–1010.
• El Sibai, R., Bachir, R. and El Sayed, M. (2018) ‘Outcomes in Post-Cardiotomy ECMO Patients: A Nationwide Analysis’, Journal of the American College of Cardiology, 72(12), pp. 1410–1420.
• Grewal, H.S., Austin, G.L., Hamilton, N. et al. (2022) ‘ECMO as a Bridge to Recovery in Massive Pulmonary Embolism’, Chest, 161(5), pp. 1124–1132.
• Lorusso, R., Raffa, G.M., Belliato, M. et al. (2021) ‘ECMO in Myocarditis: A Multicenter Cohort Study’, Critical Care Medicine, 49(2), pp. 314–323.
• Malik, A.S., Brogan, T.V., Paden, M.L. et al. (2018) ‘Peripheral versus Central Cannulation in ECMO: A Comparative Analysis’, Journal of Thoracic and Cardiovascular Surgery, 156(6), pp. 2150–2160.
• Ouweneel, D.M., de Brabander, J., Karami, M. et al. (2016) ‘ECMO in Acute Myocardial Infarction with Cardiogenic Shock’, Circulation, 134(16), pp. 1261–1270.
• Pappalardo, F., Schulte, C., Pieri, M. et al. (2019) ‘Predictors of Survival in VA-ECMO after Cardiac Surgery’, Journal of Heart and Lung Transplantation, 38(8), pp. 882–890.
• Takayama, H., Truby, L., Koene, Y. et al. (2020) ‘Clinical Outcomes in ECMO for Cardiogenic Shock’, Journal of the American Heart Association, 9(14), p. e015515