Modalities of Extracorporeal Life Support (ECLS)

• Cardiopulmonary Bypass (CPB) (see Cardiopulmonary Bypass, [[Cardiopulmonary Bypass]])
• Extracorporeal CO2 Removal (ECCO2R): originally developed by Gattinoni (JAMA, 1986) [MEDLINE]
• Extracorporeal Membrane Oxygenation (ECMO)
  • Venovenous Extracorporeal Membrane Oxygenation (VV-ECMO) (see Venovenous Extracorporeal Membrane Oxygenation, [[Venovenous Extracorporeal Membrane Oxygenation]])
  • Venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO) (Percutaneous Cardiopulmonary Support, CPS)

Differences Between Cardiopulmonary Bypass and Extracorporeal Membrane Oxygenation (ECMO) (see Cardiopulmonary Bypass, [[Cardiopulmonary Bypass]])

• Cardiopulmonary Bypass is Equipped with Reservoir Into Which Blood from the Heart is Drained: allows a bloodless surgical field for valve and aortic operations
  • In Contrast, the ECMO Circuit Does Not Contain a Reservoir, So Blood Flow Needs to Be Continuous
• Cardiopulmonary Bypass Can Be Utilized in Conjunction with Air Vent Tubing, Cardioplegia Line for Myocardial Preservation, or Cell Salvage Tubing
• Requirement for Systemic Heparin Anticoagulation is Less Intense for ECMO Because Blood Flow is Continuous and There is No Blood-Air Interface in the Reservoir
  • Higher Flow Rates of >4 L/min are Used During ECMO (in Contrast to the Lower Flow Rates of 2 L/min Used During CPB)
  • However, Continuous Anticoagulation is Necessary to Prevent Thrombus Formation on the Synthetic Thrombogenic Surfaces of Both CPB and ECMO
• ECMO Circuits are Designed for Longer-Term Use (May Be Used for Weeks, Depending on the Life of the Membrane Oxygenator), While CPB Use is Designed for Use for a Period of Hours

Indications

General Comments

• Venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO) Provides Both Respiratory and Hemodynamic Support (see Cardiac Assist Devices, [[Cardiac Assist Devices]]): VA-ECMO does not depend on the patient’s intrinsic cardiac output
  • Provides full cardiopulmonary support (hemodynamic support + oxygenation of venous blood) analogous to that provided by cardiopulmonary bypass during cardiac surgery
• Mainly Used in the Cardiac Catheterization Laboratory: mainly due to the requisite delay between the acute event and achievement of full cardiopulmonary support

Cardiac Arrest (see Cardiac Arrest, [[Cardiac Arrest]])

• General Comments: use of VA-ECMO is the setting of refractory cardiac arrest has been termed “eCPR”
• Etiology
  • Acute Myocardial Infarction (see Cardiogenic Shock, [[Cardiogenic Shock]])

Refractory Cardiogenic Shock (see Cardiogenic Shock, [[Cardiogenic Shock]])

Etiology

• Acute Myocardial Infarction (see Cardiogenic Shock, [[Cardiogenic Shock]])
• Congestive Heart Failure (CHF) (see Congestive Heart Failure, [[Congestive Heart Failure]])
• Drug Intoxication
• Fulminant Myocarditis (see Myocarditis, [[Myocarditis]])
• Intractable Arrhythmias
  • Ventricular Tachycardia (VT) (see Ventricular Tachycardia, [[Ventricular Tachycardia]])
• Post-Cardiotomy Cardiac Failure

Clinical Efficacy

• Cochrane Review of VV-ECMO and VA-ECMO in Critically Ill Adults (Cochrane Database Syst Rev, 2015) [MEDLINE]
  • xxxx

High-Risk Percutaneous Transluminal Coronary Angioplasty (PTCA)

• May be inserted prophylactically or as required for high-risk procedures

Refractory Cardiovascular Dysfunction Associated with Septic Shock

• Clinical Efficacy
  • Small Trial of VA-ECMO in Refractory Septic Shock (Critical Care Med, 2013) [MEDLINE]: small study of 14 patients
    • VA-ECMO Rescued 70% of Patients in this Small Study

Pulmonary Hypertension (see Pulmonary Hypertension, [[Pulmonary Hypertension]])

• Clinical Efficacy
  • Small Study of VA-ECMO as a Bridge to Transplant in Non-Ventilated Patients with Pulmonary Hypertension (Am J Transplant, 2010) [MEDLINE]
    • VA-ECMO May Be Feasible as a Bridge to Transplant in Non-Ventilated Patients with Pulmonary Hypertension

Contraindications

Absolute

• Unrecoverable Cardiac Function in a Patient Who is Not a Candidate for Cardiac Transplant or LVAD

Relative

• Aortic Dissection (see Aortic Dissection, [[Aortic Dissection]])
• Coagulopathy (see Coagulopathy, [[Coagulopathy]])
• Contraindication to Anticoagulation
  • Active Hemorrhage: although in patients with severe bleeding, anticoagulation can be held for limited periods of time
  • Intracerebral Hemorrhage
  • Recent Surgery
• Mechanical Ventilation >7-10 Days
• Multiorgan Failure
• Recent Ischemic Cerebrovascular Accident (CVA) (see Ischemic Cerebrovascular Accident, [[Ischemic Cerebrovascular Accident]])
• Recent Head Trauma (see Traumatic Brain Injury, [[Traumatic Brain Injury]])
• Severe Peripheral Vascular (Artery) Disease (see Peripheral Vascular Disease, [[Peripheral Vascular Disease]])
• Severe Aortic Insufficiency (AI) (see Aortic Insufficiency, [[Aortic Insufficiency]])
• Uncontrolled Sepsis (see Sepsis, [[Sepsis]])

Technique

Equipment

• General Comments
  • Pump Characteristics: pumps can usually generate up to 8-10 L/min of flow (with flow rates being generally limited by venous preload and cannula size)
  • Requirement for Continuous Technical Support (On-Site Perfusionist)
  • Duration of Use: may be used for up to 30 days
• Systems
  • Bard Cardiopulmonary Support (CPS): requires placement of large bore catheters with tips positioned in the aorta and right atrium
    • Blood from the venous catheter is pumped through a heat exchanger/oxygenator and returned to the systemic arterial circulation via the arterial cannula
  • MagLev Centrifugal Pump in Combination with Long-Term Oxygenators (CentraMag plus Maquet Quadrox)
  • Maquet CardioHelp
  • Maquet Rotaflow
    • Duration of Use: XXXXX

Vascular Access

• Venous Catheter in Inferior Vena Cava or Right Atrium (Long Catheter): venous blood is removed from the patient
• Arterial Catheter in Femoral Artery (Short Catheter): oxygenated blood is delivered retrograde up the descending aorta and into the ascending aorta to assure delivery to the coronary arteries and great vessels
  • If the Left Ventricular Cardiac Output is Negligible: the required extracorporeal flow will be low
  • As the Left Ventricular Cardiac Output Recovers and Cardiac Output Increases: the required extracorporeal flow will need to increase
    • In this case, anterograde aortic flow will compete with retrograde flow from the femoral arterial cannula, and a mixing zone of anterograde deoxygenated (in patients with respiratory failure) and retrograde oxygenated blood flow will occur: the flow required to assure that this mixing zone remains in the ascending aorta will increase as the native CO increases
    • Monitoring pulse oximetry from the right upper extremity or arterial blood gases from the right radial artery will elucidate whether VA-ECMO is providing adequate cerebral (although not necessarily cardiac) oxygenation

Anticoagulation

• Heparin Drip (see Heparin, [[Heparin]])

Management

• VA-ECMO Blood Flow Rate (Red Arrow in Photograph Denotes the RPM with the Flow Rate Adjacent to It)

Adverse Effects/Complications

Complications Directly Related to the ECMO Circuit (NEJM, 2011) [MEDLINE]

• Cannula-Related Problems
• Disseminated Intravascular Coagulation (DIC) (see Disseminated Intravascular Coagulation, [[Disseminated Intravascular Coagulation]])
• Hemolysis (see Hemolytic Anemia, [[Hemolytic Anemia]]): accounts for 6.9% of adverse events
• Hemorrhage: most common complication (occurs in 34% of cases)
  • Surgical Site
  • Cannulation-Site Hemorrhage
  • Pulmonary Hemorrhage (see Diffuse Alveolar Hemorrhage, [[Diffuse Alveolar Hemorrhage]])
  • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]])
  • Intracranial Hemorrhage
• Infection (Related to or Unrelated to ECMO)
• Ischemic Cerebrovascular Accident (CVA) (see Ischemic Cerebrovascular Accident, [[Ischemic Cerebrovascular Accident]]): stroke rates have been reported to be as high as 8% (Crit Care Med, 2008) [MEDLINE]
• Local Arterial or Venous Complications: improving technique has decreased the vascular complication rate to approximately 1.4% of cases
  • Lower Limb Ischemia (see Acute Limb Ischemia, [[Acute Limb Ischemia]]): this risk can decreased by using a small anterograde perfusion cannula in the supercial femoral artery, to perfuse the leg distal to the femoral arterial cannula
• Other Mechanical Complications
• Oxygenator Failure
• Thrombosis: second most common complication (occurs in 17% of cases)
  • Thrombosis in Oxygenator
  • Thrombosis in Other Circuit
• Thrombocytopenia (see Thrombocytopenia, [[Thrombocytopenia]])
  • Epidemiology: common
  • Physiology
    • Heparin-Induced Thrombocytopenia (HIT) (see Heparin-Induced Thrombocytopenia, [[Heparin-Induced Thrombocytopenia]])
    • Platelet Consumption in ECMO Circuit: due to fibrin stranding in oxygenator

References

• Extracorporeal membrane oxygenation in severe acute respiratory failure. A randomized prospective study. JAMA. 1979 Nov 16;242(20):2193-6 [MEDLINE]
• Low-frequency positive-pressure ventilation with extracorporeal CO2 removal in severe acute respiratory failure. JAMA. 1986;256(7):881-886 [MEDLINE]
• Randomized clinical trial of pressure-controlled inverse ratio ventilation and extracorporeal CO2 removal for adult respiratory distress syndrome. Am J Respir Crit Care Med. 1994 Feb;149(2 Pt 1):295-305 [MEDLINE]
• Venoarterial extracorporeal membrane oxygenation for treatment of cardiogenic shock: clinical experiences in 45 adult patients. J Thorac Cardiovasc Surg. 2008;135(2):382–388 [MEDLINE]
• Outcomes and long-term quality-of-life of patients supported by extracorporeal membrane oxygenation for refractory cardiogenic shock. Crit Care Med. 2008;36:1404–1411 [MEDLINE]
• Review of ECMO (extra corporeal membrane oxygenation) support in critically ill adult patients.  Heart Lung Circ  2008;17:S41–S47.  doi: 10.1016/j.hlc.2008.08.009. Epub 2008 Oct 29 [MEDLINE]
• Extracorporeal Life Support Organization (ELSO). Patient Specific Supplements to the ELSO General Guidelines, 2009. http://square.umin.ac.jp/jrcm/pdf/ecmo/ecmotext12.pdf
• Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet. 2009 Oct 17;374(9698):1351-63 [MEDLINE]
• Extracorporeal Membrane Oxygenation for 2009 Influenza A (H1N1) Acute Respiratory Distress Syndrome. JAMA. 2009 Nov 4;302(17):1888-95 [MEDLINE]
• Extracorporeal Life Support Organization. Patient specific guidelines: a supplement to the ELSO general guidelines. April 2009:15-19 (http://www.elso.med.umich .edu/WordForms/ELSO%20P+%20Specif ic %20Guidelines.pdf)
• Early and intermediate results of rescue extracorporeal membrane oxygenation in adult cardiogenic shock. Ann Thorac Surg. 2009;88(6):1897–1903 [MEDLINE]
• Extracorporeal membrane oxygenation in nonintubated patients as bridge to lung transplantation. Am J Transplant 2010;10:2173–2178 [MEDLINE]
• A review of the fundamental principles and evidence base in the use of extracorporeal membrane oxygenation (ECMO) in critically ill adult patients. J Intensive Care Med. 2011;26:13– 26. doi: 10.1177/0885066610384061 [MEDLINE]
• Extracorporeal membrane oxygenation for ARDS in adults.  N Engl J Med.  2011;365:1905–1914 [MEDLINE]
• Extracorporeal membrane oxygenation for respiratory failure in adults.  Curr Opin Crit Care Med.  2012;18:99–104 [MEDLINE]
• Venovenous extracorporeal membrane oxygenation in adults: Practical aspects of circuits, cannulae, and procedures.  J Cardiothorac Vasc Anesth 2012;26:893–909 [MEDLINE]
• Venoarterial extracorporeal membrane oxygenation support for refractory cardiovascular dysfunction during severe bacterial septic shock. Crit Care Med. 2013 Jul;41(7):1616-26. doi: 10.1097/CCM.0b013e31828a2370 [MEDLINE]
• Extracorporeal life support devices and strategies for management of acute cardiorespiratory failure in adult patients: a comprehensive review. Crit Care. 2014;18(3):219–229 [MEDLINE]
• Mechanical ventilation during extracorporeal membrane oxygenation. Crit Care. 2014 Jan 21;18(1):203. doi: 10.1186/cc13702 [MEDLINE]
• Roller and Centrifugal Pumps: A Retrospective Comparison of Bleeding Complications in Extracorporeal Membrane Oxygenation. ASAIO J. 2015 Sep-Oct;61(5):496-501. doi: 10.1097/MAT.0000000000000243 [MEDLINE]
• Extracorporeal membrane oxygenation for critically ill adults. Cochrane Database Syst Rev. 2015 Jan 22;1:CD010381. doi: 10.1002/14651858.CD010381.pub2 [MEDLINE]
• Extracorporeal membrane oxygenation in adults with cardiogenic shock. Circulation. 2015;131(7): 676–680 [MEDLINE]
• Contemporary extracorporeal membrane oxygenation therapy in adults: Fundamental principles and systematic review of the evidence [MEDLINE]