The following article highlights various steps involved in initiating and maintaining veno-arterial extracorporeal membrane oxygenation in patients with cardiogenic shock.
Cardiogenic shock (CS) is a clinical condition characterized by inadequate tissue perfusion in the setting of low cardiac output. CS is the leading cause of death following acute myocardial infarction (AMI). Several temporary mechanical support devices are available for hemodynamic support in CS until clinical recovery ensues or until more definitive surgical procedures have been performed. Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) has evolved as a powerful treatment option for short-term circulatory support in refractory CS. In the absence of randomized clinical trials, the utilization of ECMO has been guided by clinical experience and based on data from registries and observational studies. Survival to hospital discharge with the use of VA-ECMO ranges from 28-67%. The initiation of ECMO requires venous and arterial cannulation, which can be performed either percutaneously or by surgical cutdown. Components of an ECMO circuit include an inflow cannula that draws blood from the venous system, a pump, an oxygenator, and an outflow cannula that returns blood to the arterial system. Management considerations post ECMO initiation include systemic anticoagulation to prevent thrombosis, left ventricle unloading strategies to augment myocardial recovery, prevention of limb ischemia with a distal perfusion catheter in cases of femoral arterial cannulation, and prevention of other complications such as hemolysis, air embolism, and Harlequin syndrome. ECMO is contraindicated in patients with uncontrolled bleeding, unrepaired aortic dissection, severe aortic insufficiency, and in futile cases such as severe neurological injury or metastatic malignancies. A multi-disciplinary shock team approach is recommended while considering patients for ECMO. Ongoing studies will evaluate whether the addition of routine ECMO improves survival in AMI patients with CS who undergo revascularization.
Cardiogenic shock (CS) is a clinical condition characterized by inadequate tissue perfusion in the setting of low cardiac output. Despite advances in reperfusion therapy, acute myocardial infarction (AMI) remains the leading cause of CS. According to an analysis of the National Inpatient Sample (NIS) database, which collects data from approximately 20% of all United States hospitalizations, 55.4% of 144,254 CS cases between 2005 and 2014 were secondary to AMI1. Other etiologies of CS include decompensated heart failure, fulminant myocarditis, post cardiotomy shock, and pulmonary embolism (PE). CS is associated with a high in-hospital mortality rate, ranging between 45-65%1,2. Thus, rapid identification of CS and correction of reversible causes is critical in improving patient survival. For instance, the Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial demonstrated that a strategy of early revascularization was associated with better survival at 6 months3 and 1 year4 compared to a strategy of initial medical stabilization in patients with CS complicating AMI.
Vasopressors and inotropes can be used to correct hypotension associated with CS, but neither have been shown to have any mortality benefit5,6,7. Short-term mechanical circulatory support (MCS) devices, on the other hand, can provide hemodynamic support in patients with refractory CS as a bridge to recovery or as a bridge to more definitive therapy. The use of MCS has seen an increase in the recent decade; however, the incidence of CS hospitalizations has outpaced the utilization of MCS8. A declining trend in the utilization of intra-aortic balloon pumps (IABP) has been countered by a relative increase in the application of intravascular micro-axial left ventricular assist devices (LVAD) (e.g., Impella and TandemHeart) and veno-arterial extracorporeal membrane oxygenation (VA-ECMO).
VA-ECMO can generate flows up to 4-6 L/min and its application in CS has gained significant popularity9. According to a global registry maintained by the Extracorporeal Life Support Organization (ELSO), the use of VA-ECMO increased from less than 500 runs per year prior to 2010 to 2,157 runs in 201510. Nonetheless, VA-ECMO is a resource-intensive modality and requires round-the-clock availability of specialized equipment and trained staff. Therefore, patient selection is critically important prior to the initiation and maintenance of ECMO in order to improve outcomes and minimize adverse events. This article discusses the steps involved in initiation of VA-ECMO, post initiation maintenance, evidence behind its use, and associated complications.
An ECMO circuit consists of an inflow cannula, centrifugal pump, oxygenator, and outflow cannula (Figure 1)11. The inflow cannula is connected via tubing to a centrifugal pump, in which a spinning rotor generates flow and pressure. From the pump, blood flows to a membrane oxygenator where gas exchange takes place12. Here, the hemoglobin is saturated with oxygen, and the degree of oxygenation is controlled by changing the flow rate and increasing or decreasing the fraction of inspired oxygen (FiO2) supplied to the oxygenator. The removal of carbon dioxide is controlled by adjusting the sweep speed of the countercurrent gas passing through the oxygenator. A heat exchanger is usually attached to the oxygenator, and the temperature of blood returning to the body can thus be adjusted. From the oxygenator, blood is returned to the patient through an outflow cannula, either peripherally in the femoral artery or centrally in the aorta.
In this protocol, various steps involved in the initiation and maintenance of VA-ECMO in patients with refractory CS are described. Some of the major complications, weaning parameters, and outcomes with the use of VA-ECMO have also been discussed.
VA-ECMO is usually employed as a rescue therapy when other management strategies fail to provide adequate hemodynamic support in CS. Cannulation involves large bore vascular access which should be performed meticulously to minimize vascular injury an…
The authors have nothing to disclose.
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Amplatz Super Stiff guidewire | Boston Scientific | 46-500, 46-501, 46-502. 46-503, 46-504, 46-517, 46-519, 46-520, 46-523, 46-525, 46-526, 46-563, 46-564, 46-509, 46-510, 46-518, 46-524 | Allows delivery of catheters across tortuous anatomies |
Impella | Abiomed | Impella 2.5, Impella CP, Impella 5.0, Impella 5.5, Impella RP | Percutaneously inserted left ventricular assist device that provides hemodynamic support in cardiogenic shock |
Inflow Cannula | Surge Cardiovascular | FEM-V1020, FEM-V1022, FEM-V1024, FEM-V1026,FEM-V1028 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Biomedicus 96600-019,021,023,025,027,029 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Biomedicus Femoral Venous 96670 – 017,019, 021, 023 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Biomedicus Multi-Stage Femoral Venous 96880-019,021,025 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Biomedicus NextGen 96600 – 115, 117, 119, 121, 123, 125, 127, 129 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Carmeda Biomedicus CB96605-015,017,019,021,023,025,29 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Cortiva Biomedicus Femoral Venous CB96670-015,017,019,021 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | DLP Carmeda Venous CB75008, CB66112, CB66114, CB66116, CB66118, CB66120, CB66122,CB66124 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Getinge | Avalon Elite Bicaval – 10013, 10016, 10019, 10020, 10023, 10027, 10031 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Getinge | HLS Cannula Venous Bioline – BE PVS 1938, 2138, 2155, 2338, 2355, 2538, 2555, 2955 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Getinge | HLS Cannula Venous Softline – BO PVS 1938, 2138, 2155, 2338, 2355, 2538, 2555, 2955 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Getinge | HLS Cannula Venous – PVS 1938, 2138, 2155, 2338, 2355, 2538, 2555, 2955 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Life Support Bio-Medicus Drainage Catheter and Introducers – LS96218 – 015, 017, 019, 021, 023, 025 ; LS96438 – 021, 023, 025, LS 96555 – 019, 021, 023, 025, LS 96355 – 021, LS96360 -023, 025, 027, 029 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Fresenius | Medos Femoral Cannula MEFKV 18,20,22,24,26,28 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Medtronic Cardiopulmonary | Medtronic 2 stage venous – 91228, 91240, 91246, 91236,91251 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Senko/Mera | PCKC-V-24, PCKC-V2-18, PCKC-V-18, PCKC-V2-20, PCKC-V-20, PCKC-V-22, PCKC-V2-24, PCKC-V-24 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | TandemLife/Livanova | 29,31 Fr | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Freelife Medical | FLK V19 B18, FLK V19 B18R, FLK VV 19R, FLK V20 B20, FLK V20 B20R, FLK V19 B20, FLK V19 B20R, FLK V20 B22, FLK V20 B22R, FLK V10S B22, FLK V19 B22, FLK V19 B22R, FLK V10 B22, FLK V10 B22R, FLK V10S B22R, FLK VV 23R, FLK V10S B24, FLK V10S B24R, FLK V10 B24, FLK V10 B24R, FLK V10S B26, FLK V10S B26R, FLK V10 B26, FLK V10 B26R, FLK VV 27R, FLK VV 31R | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | LivaNova | Sorin right angle venous – 10, 12, 14, 16, 18, 20, 22, 24, 28 | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Inflow Cannula | Terumo | CX-EB18VLX, CX-EB21VLX | Removes deoxygenated blood from the central venous circulation into the ECMO circuit |
Outflow Cannula | Medtronic Cardiopulmonary | Biomedicus Arterial 96530 – 015,017, 019, 021, 023, 025, | Returns oxygenated blood to the body |
Outflow Cannula | Medtronic Cardiopulmonary | Biomedicus Femoral Arterial 96570 – 015, 017, 019, 021 | Returns oxygenated blood to the body |
Outflow Cannula | Medtronic Cardiopulmonary | Biomedicus NextGen Arterial 96530 -115, 117, 119, 121, 123, 125, 96570 – 115, 117, 119, 121 | Returns oxygenated blood to the body |
Outflow Cannula | Medtronic Cardiopulmonary | Carmeda Biomedicus CB96535 – 015, 017, 019, 021, 023 | Returns oxygenated blood to the body |
Outflow Cannula | Medtronic Cardiopulmonary | Cortiva Biomedicus Femoral Arterial CB96570 -015, 017, 019, 021 | Returns oxygenated blood to the body |
Outflow Cannula | Getinge | PAS 1315, PAS 1515, PAS 1523, PAS 1717, PAL 1723, PAL 1923, PAL 2115, PAL 2123, PAL 2315, PAL 2323 | Returns oxygenated blood to the body |
Outflow Cannula | Getinge | Bioline BE PAS 1315, BE PAS 1515, BE PAL 1523, BE PAL 1723, BE PAS 1915, BE PAL 1923, BE PAS 2115, BE PAL 2123, BE PAS 2315, BE PAL 2323, | Returns oxygenated blood to the body |
Outflow Cannula | Getinge | Softline BO PAS 1315, BO PAS 1515, BO PAL 1523, BO PAS 1715, BO PAL 1723, BO PAS 1915, BO PAL 1923, BO PAS 2115, BO PAL 2123, BO PAL 2323 | Returns oxygenated blood to the body |
Outflow Cannula | Fresenius | Medos Femoral Arterial Cannula; MEFKA 16, 18, 20, 22,24 | Returns oxygenated blood to the body |
Outflow Cannula | Senko/Mera | PCKC-A-20, PCKC-A-16, PCKC-A-18 | Returns oxygenated blood to the body |
Outflow Cannula | Freelife Medical | FLK A18 D16, FLK A18L D16, FLK A18L D16R, FLK A18 D16R, FLK A44 D18, FLK A44 D18R, FLK A18 D18, FLK A18L D18, FLK A18L D18R, FLK A18 D18R, FLK A44 D20, FLK A44 D20R, FLK A18 D20, FLK A18L D20, FLK A18L D20R, FLK A18 D20R, FLK A18 D22, FLK A18L D22, FLK A18L D22R, FLK A18 D24, FLK A18L D24, FLK A18L D24R, FLK A18 D24R | Returns oxygenated blood to the body |
Outflow Cannula | LivaNova | Sorin arterial – 14, 17, 19, 21, 23 Fr | Returns oxygenated blood to the body |
Outlflow Cannula | Medtronic Cardiopulmonary | Life Support Bio-Medicus Return Catheter and Introducers – LS96010-009, LS96010-011, LS96010-013, LS96010-015, LS96218-015, LS96218-017, LS96218-019, LS96218-021, LS96218-023, LS96218-025 | Returns oxygenated blood to the body |
Oxygenator | Abbott | Eurosets | Deoxygenated blood from the inflow cannula is saturated with oxygen |
Oxygenator | Getinge | MaquetHLS Set Advanced v 5.0, v 7.0, Maquet Quadrox iD | Deoxygenated blood from the inflow cannula is saturated with oxygen |
Oxygenator | Medtronic | Nautilus | Deoxygenated blood from the inflow cannula is saturated with oxygen |
Pump | Abiomed | Breethe | Generates force to deliver oxygenated blood back to the body |
Pump | LivaNova | Alcard ALC 250 | Generates force to deliver oxygenated blood back to the body |
Pump | Baxter | Century Roller Pump | Generates force to deliver oxygenated blood back to the body |
Pump | Medtronic Cardiopulmonary | Biomedicus BP50, BP80 Centrifugal | Generates force to deliver oxygenated blood back to the body |
Pump | Braile Biomedica | Safyre | Generates force to deliver oxygenated blood back to the body |
Pump | Getinge | CiSet | Generates force to deliver oxygenated blood back to the body |
Pump | Abbott | CentriMag | Generates force to deliver oxygenated blood back to the body |
Pump | LivaNova | Cobe 6" Roller | Generates force to deliver oxygenated blood back to the body |
Pump | Origen | FloPump 32 | Generates force to deliver oxygenated blood back to the body |
Pump | Getinge | HIT Set Advanced Softline 5.0 and 7.0 | Generates force to deliver oxygenated blood back to the body |
Pump | LivaNova | LifeSPARC | Generates force to deliver oxygenated blood back to the body |
Pump | Senko/Mera | Centrifugal pump head | Generates force to deliver oxygenated blood back to the body |
Pump | Getinge | HLS Set Advanced Bioline 5.0 and 7.0 | Generates force to deliver oxygenated blood back to the body |
Tandem Heart | LivaNova | Tandem Heart LS | Percutaneously inserted left ventricular assist device |
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