Update on Weaning from Veno-Arterial Extracorporeal Membrane Oxygenation

Abstract

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides temporary cardiac and respiratory support and has emerged as an established salvage intervention for patients with hemodynamic compromise or shock. It is thereby used as a bridge to recovery, bridge to permanent ventricular assist devices, bridge to transplantation, or bridge to decision. However, weaning from VA-ECMO differs between centers, and information about standardized weaning protocols are rare. Given the high mortality of patients undergoing VA-ECMO treatment, it is all the more important to answer the many questions still remaining unresolved in this field Standardized algorithms are recommended to optimize the weaning process and determine whether the VA-ECMO can be safely removed. Successful weaning as a multifactorial process requires sufficient recovery of myocardial and end-organ function. The patient should be considered hemodynamically stable, although left ventricular function often remains impaired during and after weaning. Echocardiographic and invasive hemodynamic monitoring seem to be indispensable when evaluating biventricular recovery and in determining whether the VA-ECMO can be weaned successfully or not, whereas cardiac biomarkers may not be useful in stratifying those who will recover. This review summarizes the strategies of weaning of VA-ECMO and discusses predictors of successful and poor weaning outcome.

Keywords: predictors of successful weaning; venoarterial extracorporeal membrane oxygenation; weaning; weaning strategy; weaning timing.

Figure 1

Standardized protocol for weaning from veno-arterial extracorporeal membrane oxygenation (VA-ECMO), according to Aissaoui et al. [21]. MAP, mean arterial pressure; PaO_2, Partial pressure of oxygen; FiO₂, fraction of inspired oxygen; LVEF, left ventricular ejection fraction; VTI, velocity-time integration; TDSa, tissue Doppler lateral mitral annulus peak systolic velocity; CI, cardiac index; PCWP, pulmonary capillary wedge pressure; CVP, central venous pressure; RV, right ventricle.

Figure 2

Standardized protocol for weaning from VA-ECMO according to Keebler et al. [18]. CVP, central venous pressure; PAM, pulmonary arterial mean pressure; MAP, mean arterial pressure; LVEF, left ventricular ejection fraction; LV, left ventricle; RV, right ventricle; VTI, velocity-time integral; SvO₂, mixed venous oxygen saturation; CI, cardiac index; MCS, mechanical circulatory support.

Figure 3

Standardized protocol for weaning from VA-ECMO according to Eckman et al. [10]. LV, left ventricle; RV, right ventricle; VTI, velocity-time integral; TDSa, tissue Doppler lateral mitral annulus peak systolic velocity; MCS, mechanical circulatory support.

Figure 4

Standardized protocol for weaning from VA-ECMO according to Cavarocchi et al. [5]. PTT, partial thromboplastin time; hTEE, hemodynamic transoesophageal echocardiography; LV, left ventricle; RV, right ventricle; LVAD, left ventricular assist device; RVAD, right ventricular assist device.

Figure 5

Standardized protocol for weaning from VA-ECMO according to Ling et al. [51]. PCRTO, Pump Controlled Retrograde Trial Off; ACT, activated clotting time; MAP, mean arterial pressure; FiO₂, fraction of inspired oxygen; SaO₂, arterial oxygen saturation.

Figure 6

Standardized protocol for weaning from VA-ECMO for graft failure after heart transplantation according to Santise et al. [53]. TEE, transoesophageal echocardiography; LVEF, left ventricular ejection fraction; LV, left ventricle.

Figure 7

VA-ECMO Weaning—University Hospital Munich, a cardiologic ICU. MAP, mean arterial pressure; ScvO₂, central venous oxygen saturation; SaO₂, arterial oxygen saturation; PaO₂, partial pressure of oxygen; FiO₂, fraction of inspired oxygen.