Liberation From Venoarterial Extracorporeal Membrane Oxygenation: A Review

Incidence and predictors of weaning failure from veno-arterial extracorporeal membrane oxygenation therapy in patients with cardiogenic shock

AIMS

This study aimed to investigate incidence and predictors of weaning failure and in-hospital death after successful weaning from veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiogenic shock (CS).

METHODS AND RESULTS

Overall, 685 patients with CS treated with VA-ECMO from 23 tertiary care centres in 7 countries were analysed (median age 57 [interquartile range 49-66] years, 542 [79.1%] male, median lactate 7.6 [interquartile range 4.1-12.7] mmol/L). The cause of CS was acute myocardial infarction in 438 (63.9%) patients, and 431 (62.9%) patients presented with cardiac arrest. A total of 410 patients (59.9%) were successfully weaned from VA-ECMO, whereas in 275 patients (40.1%) weaning failed (i.e. patients died on or within 48 h after VA-ECMO support). Of the successfully weaned patients, 150 (36.6%) died before hospital discharge. On multivariable logistic regression, predictors for both patient groups varied: age (per 10 years, odds ratio [OR] 1.49, 95% confidence interval [CI] 1.25-1.76; p < 0.001) and cardiac arrest before VA-ECMO implantation (OR 1.64, 95% CI 1.01-2.64; p = 0.04) were associated with weaning failure, whereas lactate clearance within 24 h after VA-ECMO initiation was associated with successful weaning (OR 0.21, 95% CI 0.1-0.44; p < 0.001). In-hospital death after successful weaning was more likely with higher age (per 10 years, OR 1.56, 95% CI 1.24-1.97; p < 0.001), renal replacement therapy (OR 2.56, 95% CI 1.4-4.68; p = 0.002) and bleeding events (OR 2.93, 95% CI 1.4-6.14; p = 0.004).

CONCLUSION

Weaning from VA-ECMO fails in 40% of patients treated with VA-ECMO for CS. When successful, survival after VA-ECMO weaning mostly depends on age and the incidence of device- and shock-related complications.

From Escalate to Elevate: A New Paradigm for Comprehensive Cardiogenic Shock Management

Patients with cardiogenic shock (CS) present with critical hemodynamic compromise with low cardiac output (CO) resulting in end-organ dysfunction. Prognosis is closely related to the severity of shock and treatment of patients with CS is resource intensive. In this review, we consider the current treatment paradigms alongside the evidence that underpins them. The current standard of treatment relies on a feedback mechanism, where small changes in treatment are assessed to see if clinical improvement occurs. This leads to delays that increase time in the shock state. The novel approach described proposes immediate treatment to ameliorate the shock state to 'break' the shock spiral as quickly and decisively as possible, suggesting new metrics to measure performance.

Initial experience with pump controlled retrograde trial-off (PCRTO) veno-arterial extra corporeal membrane oxygenation in children

Pump Controlled Retrograde Trial Off (PCRTO) is a relatively new technique in trialing-off Veno-Arterial Extra Corporeal Membrane Oxygenation (VA-ECMO). Literature on the use of PCRTO in children remains scarce. We describe our centre's initial experience with PCRTO in a neonate and an older child and review its potential advantages and disadvantages compared to traditional weaning methods. More research and shared best practices are required in children to facilitate wider adoption of this technique.

Pragmatic approach to temporary mechanical circulatory support in acute right ventricular failure

Acute right ventricular failure (RVF) is prevalent in multiple disease states and is associated with poor clinical outcomes. Right-sided temporary mechanical circulatory support (tMCS) devices are used to unload RV congestion and increase cardiac output in cardiogenic shock (CS) with hemodynamically significant RVF. Several RV-tMCS device platforms are available; however consensus is lacking on patient selection, timing of escalation to RV-tMCS, device management, and device weaning. The purposes of this review are to 1) describe the current state of tMCS device therapies for acute RVF with CS, 2) discuss principles of escalation to RV-tMCS device therapy, 3) examine important aspects of clinical management for patients supported by RV-tMCS devices including volume management, anticoagulation, and positive pressure ventilation, and 4) provide a framework for RV-tMCS weaning.

Factors Influencing Successful Weaning From Venoarterial Extracorporeal Membrane Oxygenation: A Systematic Review

With advancements in extracorporeal life support (ECLS) technologies, venoarterial extracorporeal membrane oxygenation (VA-ECMO) has emerged as a crucial cardiopulmonary support mechanism. This review explores the significance of VA-ECMO system configuration, cannulation strategies, and timing of initiation. Through an analysis of medication management strategies, complication management, and comprehensive preweaning assessments, it aims to establish a multidimensional evaluation framework to assist clinicians in making informed decisions regarding weaning from VA-ECMO, thereby ensuring the safe and effective transition of patients.

Discontinuation of Cardiac Devices at or Near an Adult Patient's End of Life

Advances in medical technology have begun to blur the lines between life and death as well as the lines between appropriate and inappropriate therapy. This review addresses the charged issue of the management of cardiac devices at or near the end of a patient's life, provides a summary of prior and current opinion with some historical context, and attempts to provide some modest guidance as to how to approach the various options to the patient's best advantage. Modalities to be addressed include indwelling electronic devices, the left ventricular assistance device, and extracorporeal mechanical oxygenation, and includes available outcome data as well as ethical analysis from a number of commentators. The expected further increase in technical sophistication of these devices is expected to render the various aspects of device deactivation more and more complex over the course of the next few years such that careful attention to and knowledge about this issue will continue to be more and more necessary.

Vascular Complications in Extracorporeal Membrane Oxygenation-A Narrative Review

The establishment of a peripheral ECMO circuit can lead to significant arterial and venous complications in 10-30% of patients. Vascular complications, particularly acute limb ischemia, are associated with worsening overall outcomes. Limb ischemia occurs significantly more frequently in the early stages of VA ECMO than in VV ECMO. Mechanisms of limb ischemia include arterial obstruction, cannulation injury, loss of pulsatile flow, thromboembolism, venous stasis from compressive obstruction with large venous cannulas, and systemic vasoconstriction due to shock and pharmacologic vasoconstriction. The care team may use several mitigation strategies to prevent limb ischemia. Arterial and venous complications can be mitigated by careful access site selection, minimizing cannula size, placement of distal perfusion and/or outflow catheter(s), and continuous NIRS monitoring. Rapid intervention, when ischemia or compartment syndrome occurs, can reduce limb loss but may not affect the mortality and morbidity of the ECMO patient in the long term due to their underlying conditions and the etiology of the ECMO need.

Novel weaning assessment for veno-arteriovenous to veno-venous extracorporeal membrane oxygenation using pump-controlled retrograde trial off

INTRODUCTION

Pump-controlled retrograde trial off (PCRTO) is described as an effective weaning strategy for veno-arterial extracorporeal membrane oxygenation (ECMO) in the guidelines. Contrastingly, there is no established weaning strategy for veno-arteriovenous (V-AV) ECMO. We report a novel application of PCRTO in a patient undergoing V-AV ECMO.

CASE REPORT

A 49-year-old man had pneumonia and a history of kidney transplantation. Two days after intubation, respiratory failure progressed and veno-venous (V-V) ECMO was introduced. On day 7 after ECMO, the configuration was changed to V-AV ECMO owing to septic cardiomyopathy due to suspected cholangitis. On day 15, with partial haemodynamic improvement and persistent respiratory failure, PCRTO was performed; the patient was safely returned to V-V ECMO.

DISCUSSION

In patients undergoing V-AV ECMO, PCRTO could have the potential to accurately simulate decannulation of the arterial cannula.

CONCLUSION

This novel weaning strategy could be considered in patients undergoing V-AV ECMO.

Head-to-toe bedside ultrasound for adult patients on extracorporeal membrane oxygenation

Bedside ultrasound represents a well-suited diagnostic and monitoring tool for patients on extracorporeal membrane oxygenation (ECMO) who may be too unstable for transport to other hospital areas for diagnostic tests. The role of ultrasound, however, starts even before ECMO initiation. Every patient considered for ECMO should have a thorough ultrasonographic assessment of cardiac and valvular function, as well as vascular anatomy without delaying ECMO cannulation. The role of pre-ECMO ultrasound is to confirm the indication for ECMO, identify clinical situations for which ECMO is not indicated, rule out contraindications, and inform the choice of ECMO configuration. During ECMO cannulation, the use of vascular and cardiac ultrasound reduces the risk of complications and ensures adequate cannula positioning. Ultrasound remains key for monitoring during ECMO support and troubleshooting ECMO complications. For instance, ultrasound is helpful in the assessment of drainage insufficiency, hemodynamic instability, biventricular function, persistent hypoxemia, and recirculation on venovenous (VV) ECMO. Lung ultrasound can be used to monitor signs of recovery on VV ECMO. Brain ultrasound provides valuable diagnostic and prognostic information on ECMO. Echocardiography is essential in the assessment of readiness for liberation from venoarterial (VA) ECMO. Lastly, post decannulation ultrasound mainly aims at identifying post decannulation thrombosis and vascular complications. This review will cover the role of head-to-toe ultrasound for the management of adult ECMO patients from decision to initiate ECMO to the post decannulation phase.

A novel 'shunt fraction' method to derive native cardiac output during liberation from central VA ECMO

The Fick principle is an established method to quantify intracardiac shunts. The Fick principle has also found utility in the practice of extracorporeal membrane oxygenation (ECMO). This report describes a novel 'shunt fraction' method to calculate intrinsic cardiac output in central (right atrial-to-aorta) ECMO. The physiological basis of this 'shunt fraction' method is described, followed by the case presentation that details the clinical application of this method of quantifying intrinsic cardiac output to guide weaning and liberation from central VA ECMO.

Postcardiotomy Shock Syndrome: A Narrative Review of Perioperative Diagnosis and Management

Postcardiotomy shock (PCS) is generally described as the inability to separate from cardiopulmonary bypass due to ineffective cardiac output after cardiotomy, which is caused by a primary cardiac disorder, resulting in inadequate tissue perfusion. Postcardiotomy shock occurs in 0.5% to 1.5% of contemporary cardiac surgery cases, and is accompanied by an in-hospital mortality of approximately 67%. In the last 2 decades, the incidence of PCS has increased, likely due to the increased age and baseline morbidity of patients requiring cardiac surgery. In this narrative review, the authors discuss the epidemiology and pathophysiology of PCS, the rationale and evidence behind the initiation, continuation, escalation, and discontinuation of mechanical support devices in PCS, and the anesthetic implications.

Monitoring during extracorporeal membrane oxygenation

PURPOSE OF REVIEW

Extracorporeal membrane oxygenation (ECMO) offers advanced mechanical support to patients with severe acute respiratory and/or cardiac failure. Ensuring an adequate therapeutic approach as well as prevention of ECMO-associated complications, by means of timely liberation, forms an essential part of standard ECMO care and is only achievable through continuous monitoring and evaluation. This review focus on the cardiorespiratory monitoring tools that can be used to assess and titrate adequacy of ECMO therapy; as well as methods to assess readiness to wean and/or discontinue ECMO support.

RECENT FINDINGS

Surrogates of tissue perfusion and near infrared spectroscopy are not standards of care but may provide useful information in select patients. Echocardiography allows to determine cannulas position, evaluate cardiac structures, and function, and diagnose complications. Respiratory monitoring is mandatory to achieve lung protective ventilation and identify early lung recovery, surrogate measurements of respiratory effort and ECMO derived parameters are invaluable in optimally managing ECMO patients.

SUMMARY

Novel applications of existing monitoring modalities alongside evolving technological advances enable the advanced monitoring required for safe delivery of ECMO. Liberation trials are necessary to minimize time sensitive ECMO related complications; however, these have yet to be standardized.

Extracorporeal Membrane Oxygenation in Infarct-Related Cardiogenic Shock

Mortality in infarct-related cardiogenic shock (CS) remains high, reaching 40-50%. In refractory CS, active mechanical circulatory support devices including veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are rapidly evolving. However, supporting evidence of VA-ECMO therapy in infarct-related CS is low. The current review aims to give an overview on the basics of VA-ECMO therapy, current evidence, ongoing trials, patient selection and potential complications.