Conversion from Venovenous to Venoarterial Extracorporeal Membrane Oxygenation in Adults

Outcomes of Adult Patients With COVID-19 Transitioning From Venovenous to Venoarterial or Hybrid Extracorporeal Membrane Oxygenation in the Extracorporeal Life Support Organization Registry

This retrospective analysis of the Extracorporeal Life Support Organization (ELSO) registry evaluates the outcomes and identifies risk factors associated with conversion from initial venovenous extracorporeal membrane oxygenation (ECMO) support to venoarterial or hybrid ECMO in patients with coronavirus disease 2019 (COVID-19). We collected deidentified data on all adult patients (≥18 years old) diagnosed with COVID who received venovenous extracorporeal membrane oxygenation between March 2020 and November 2022. Patients initially placed on an ECMO configuration other than venovenous (VV) ECMO were excluded from the analysis. Our analysis included data from 12,850 patients, of which 393 (3.1%) transitioned from VV ECMO to an alternative mode. The primary outcome measure was in-hospital mortality, and the conversion group exhibited a higher in-hospital mortality rate. We also examined baseline variables, including demographic information, biochemical labs, and inotrope requirements. Univariate analysis revealed that pre-ECMO arrest, the need for renal replacement therapy, and the use of inotropic agents, particularly milrinone, were strongly associated with the risk of conversion. Notably, even after implementing a 3:1 propensity score matching, the impact of conversion on both mortality and complications remained substantial. Our study underscores an elevated risk of mortality for COVID-19 patients initially treated with VV ECMO who subsequently require conversion to VA-ECMO or hybrid ECMO.

Cardiac Tamponade Complicating Extracorporeal Membrane Oxygenation: An Extracorporeal Life Support Organization Registry Analysis

OBJECTIVES

Cardiac tamponade is a potentially life-threatening complication during extracorporeal membrane oxygenation (ECMO). In this study, the authors assessed the incidence, patient characteristics, and risk factors for mortality of cardiac tamponade during ECMO.

DESIGN

The authors queried the Extracorporeal Life Support Organization (ELSO) Registry from 1997 to 2021 for all adults with cardiac tamponade as a reported complication during ECMO.

PARTICIPANTS

Cardiac tamponade was reported in 2,176 (64% men; 53.8 ± 0.33 years) of 84,430 adults (2.6%).

MEASUREMENTS AND MAIN RESULTS

Venoarterial ECMO was the main configuration (78%), followed by venovenous ECMO (VV ECMO) (18%), for cardiac (67%), pulmonary (21%) support, and extracorporeal cardiopulmonary resuscitation (ECPR) (12%). Percutaneous cannulation was performed in 51%, with the femoral vein and femoral artery as the most common sites for drainage and return cannulae, with dual-lumen cannulae in 39% of VV ECMO. Hospital survival was lower (35% v 49%; p < 0.01) when compared with that of all adults from the ELSO Registry. In multivariate analysis, age, aortic dissection and/or rupture, COVID-19, ECPR, pre-ECMO renal-replacement therapy, and prone position are associated with hospital mortality, whereas ECMO for pulmonary support is associated with hospital survival. Similarly, renal, cardiovascular, metabolic, neurologic, and pulmonary complications occurred more frequently in nonsurvivors.

CONCLUSIONS

Cardiac tamponade is a rare complication during ECMO that, despite being potentially reversible, is associated with high hospital mortality. Venoarterial ECMO is the most common configuration. ECMO for pulmonary support was associated with higher survival, and ECPR was associated with higher mortality. In these patients, other ECMO-related complications were frequently reported and associated with hospital mortality.

Severe Lung Dysfunction and Pulmonary Blood Flow during Extracorporeal Membrane Oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is indicated for patients with severe respiratory and/or circulatory failure. The standard technique to visualize the extent of pulmonary damage during ECMO is computed tomography (CT).

PURPOSE

This single-center, retrospective study investigated whether pulmonary blood flow (PBF) measured with echocardiography can assist in assessing the extent of pulmonary damage and whether echocardiography and CT findings are associated with patient outcomes.

METHODS

All patients (>15 years) commenced on ECMO between 2011 and 2017 with septic shock of pulmonary origin and a treatment time >28 days were screened. Of 277 eligible patients, 9 were identified where both CT and echocardiography had been consecutively performed.

RESULTS

CT failed to indicate any differences in viable lung parenchyma within or between survivors and non-survivors at any time during ECMO treatment. Upon initiation of ECMO, the survivors (n = 5) and non-survivors (n = 4) had similar PBF. During a full course of ECMO support, survivors showed no change in PBF (3.8 ± 2.1 at ECMO start vs. 7.9 ± 4.3 L/min, p = 0.12), whereas non-survivors significantly deteriorated in PBF from 3.5 ± 1.0 to 1.0 ± 1.1 L/min (p = 0.029). Tidal volumes were significantly lower over time among the non-survivors, p = 0.047.

CONCLUSIONS

In prolonged ECMO for pulmonary septic shock, CT was not found to be effective for the evaluation of pulmonary viability or recovery. This hypothesis-generating investigation supports echocardiography as a tool to predict pulmonary recovery via the assessment of PBF at the early to later stages of ECMO support.

Extracorporeal membrane oxygenation in South Africa: Experience from a single centre in the private sector

Background

Extracorporeal membrane oxygenation (ECMO) is an advanced, resource-intensive technology used in a limited capacity in South Africa (SA). Minimal data on the use of ECMO in SA are available.

Objectives

To describe the indications, early outcome and comorbidities of patients placed on ECMO in the highest-volume ECMO centre in SA.

Methods

We performed a single-centre retrospective review of all adult patients supported with any form of ECMO from August 2016 to December 2018. Operative and clinical records were reviewed. The primary objective of this study was to review the outcome of patients placed on ECMO in the form of survival to hospital discharge. The secondary objectives were to identify population-specific comorbidities and indications for ECMO that could be associated with non-survival and to compare outcome with known risk scores in the form of the Respiratory ECMO Survival Prediction (RESP) and Survival After Venoarterial ECMO (SAVE) scores.

Results

One hundred and seven patients were identified. The primary indication for ECMO was respiratory support in 78 patients and cardiac support in 29 patients. Forty-seven patients were discharged from hospital, with a 44.0% overall survival rate. Gender (p=0.039), age (p=0.019) and hypertension (p=0.022) were associated with death in univariate logistic regression analysis. However, after adjusting for potential confounding in multivariate logistic regression analysis, the association was no longer significant. In the all respiratory support group, patients in risk class IV had better than predicted survival according to the RESP score, while risk classes I, II and III had worse than predicted survival. In the circulatory support group, all risk classes had worse than predicted survival according to the SAVE score.

Conclusion

We report ECMO outcomes in SA for the first time. We identified very high mortality rates for patients transferred on ECMO from other facilities and for patients converted from venovenous ECMO to venoarterial ECMO. Although our outcomes were comparable in some of the risk classes, further external validation of the SAVE and RESP scores will be needed to compare our outcomes with these scores.

Study synopsis

What the study adds. We report on extracorporeal membrane oxygenation (ECMO) outcomes in South Africa for the first time. We identified a high mortality rate in patients transferred on ECMO from other facilities, and in patients converted from venovenous ECMO to venoarterial ECMO.Implications of the findings. Transferred patients had a high mortality rate. The reason for this should be further investigated and may highlight the need for possible protocols to assist with appropriate timing of patient transfers and possible earlier intervention or transfer.

Utilization and outcomes of V-AV ECMO: A systematic review and meta-analysis

BACKGROUND

Veno-arterial-venous extracorporeal membrane oxygenation (V-AV ECMO) is a less commonly used configuration of ECMO. We sought to understand the indications, utilization patterns, and outcomes of V-AV ECMO by quantitatively pooling the existing evidence from the literature.

METHODS

Electronic search was performed to identify all relevant studies reporting V-AV ECMO usage. Five studies comprising 77 patients were selected and cohort-level data were extracted for further analysis.

RESULTS

Mean patient age was 61 (95% CI: 55.2, 66.5) years and 30% (23/77) were female. The majority of cases [91% (70/77)] were transitioned to V-AV ECMO from another pre-existing ECMO configuration: V-A ECMO in 55% (42/77) vs. V-V ECMO in 36% (28/77), p = 0.04. Only 9% (7/77) of cases were directly placed on V-AV ECMO. The mean duration of hospital stay was 42.3 (95% CI: 10.5, 74.2) days, while ICU mortality was 46% (29, 64). Transition to durable left ventricular assist device was performed in 3% (2/64) of patients, while 3% (2/64) underwent heart transplantation. V-AV ECMO was successfully weaned to explantation in 33% (21/64) of patients.

CONCLUSION

V-AV ECMO is a viable option for optimizing cardiopulmonary support in selected patients. Survival to weaning or bridging therapy appears comparable to more common ECMO configurations.

Incidence and predictors of brain infarction in neonatal patients on extracorporeal membrane oxygenation: an observational cohort study

To determine the incidence and identify predictors of brain infarctions (BI) in neonatal patients treated with extracorporeal membrane oxygenation (ECMO). We performed a retrospective cohort study at ECMO Centre Karolinska, Stockholm, Sweden. Logistic regression models were used to identify BI predictors. Neonates (age 0-28 days) treated with veno-arterial (VA) or veno-venous (VV) ECMO between 2010 and 2018. The primary outcome was a computed tomography (CT) verified BI diagnosed during ECMO treatment. In total, 223 patients were included, 102 patients (46%) underwent at least one brain CT and 27 patients (12%) were diagnosed with a BI. BI diagnosis was associated with increased 30-day mortality (48% vs. 18%). High pre-ECMO Pediatric Index of Mortality score, sepsis as the indication for ECMO treatment, VA ECMO, conversion between ECMO modes, use of continuous renal replacement therapy, and extracranial thrombosis were identified as independent predictors of BI development. The incidence of BI in neonatal ECMO patients may be higher than previously understood. Risk factor identification may help initiate steps to lower the risk or facilitate earlier diagnosis of BI in neonates undergoing ECMO treatment.

Outcomes of patients with acute respiratory failure on veno-venous extracorporeal membrane oxygenation requiring additional circulatory support by veno-venoarterial extracorporeal membrane oxygenation

Objective

Veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) is increasingly used to support patients with severe acute respiratory distress syndrome (ARDS). In case of additional cardio-circulatory failure, some experienced centers upgrade the V-V ECMO with an additional arterial return cannula (termed V-VA ECMO). Here we analyzed short- and long-term outcome together with potential predictors of mortality.

Design

Multicenter, retrospective analysis between January 2008 and September 2021.

Setting

Three tertiary care ECMO centers in Germany (Hannover, Bonn) and Switzerland (Zurich).

Patients

Seventy-three V-V ECMO patients with ARDS and additional acute cardio-circulatory deterioration required an upgrade to V-VA ECMO were included in this study.

Measurements and main results

Fifty-three patients required an upgrade from V-V to V-VA and 20 patients were directly triple cannulated. Median (Interquartile Range) age was 49 (28–57) years and SOFA score was 14 (12–17) at V-VA ECMO upgrade. Vasoactive-inotropic score decreased from 53 (12–123) at V-VA ECMO upgrade to 9 (3–37) after 24 h of V-VA ECMO support. Weaning from V-VA and V-V ECMO was successful in 47 (64%) and 40 (55%) patients, respectively. Duration of ECMO support was 12 (6–22) days and ICU length of stay was 32 (16–46) days. Overall ICU mortality was 48% and hospital mortality 51%. Two additional patients died after hospital discharge while the remaining patients survived up to two years (with six patients being lost to follow-up). The vast majority of patients was free from higher degree persistent organ dysfunction at follow-up. A SOFA score > 14 and higher lactate concentrations at the day of V-VA upgrade were independent predictors of mortality in the multivariate regression analysis.

Conclusion

In this analysis, the use of V-VA ECMO in patients with ARDS and concomitant cardiocirculatory failure was associated with a hospital survival of about 50%, and most of these patients survived up to 2 years. A SOFA score > 14 and elevated lactate levels at the day of V-VA upgrade predict unfavorable outcome.

Differential hypoxemia and the clinical significance of venous drainage position during extracorporeal membrane oxygenation

Differential hypoxemia (DH) has been recognized as a clinical problem during veno-arterial extracorporeal membrane oxygenation (VA ECMO) although its features and consequences have not been fully elucidated.

This single center retrospective study aimed to investigate the clinical characteristics of patients manifesting DH as well as the impact of repositioning the drainage point from the inferior vena cava (IVC) to the superior vena cava to alleviate DH.

All patients (>15 years) commenced on VA ECMO at our center between 2009 and 2020 were screened. Of 472 eligible patients seven were identified with severe DH. All patients had the drainage cannula tip in the IVC or at the junction between the IVC and right atrium.

The mean peripheral capillary saturation increased from 54 (±6.6) to 86 (±6.6) %, (p = <0.001) after repositioning of the cannula. Pre-oxygenator saturation increased from 62 (±8.9) % prior to adjustment to 74 (±3.7) %, (p = 0.016) after repositioning. Plasma lactate tended to decrease within 24 h after adjustment. Five patients (71%) survived ECMO treatment, to discharge from hospital, and were alive at 1-year follow-up.

Although DH has been described in several studies, the condition has not been investigated in a clinical setting comparing the effect on upper body saturation before and after repositioning of the drainage cannula. This study shows that moving the drainage zone into the upper part of the body has a marked positive effect on upper body saturation in patients with DH.

Extracorporeal membrane oxygenation in the forensic setting: A series of 19 forensic cases

Extracorporeal membrane oxygenation (ECMO) employs vascular cannulation and a gas exchange circuit to provide support to patients with severely compromised cardiopulmonary function. ECMO is often the last intervention taken before death and thus presents a unique challenge to medical examiners. This study describes the characteristics of decedents on ECMO at the time of death, including clinical indications, types of circuit configurations, causes and manners of death, gross findings at autopsy, and therapeutic complications. Files of a regional medical examiner office within an academic medical center were searched for the period between 2013 and 2019. Nineteen cases were identified with a median age of 36 years. The circumstances surrounding the initial presentation included: sudden death, trauma, substance abuse, homicide, therapeutic complication, work-related injury, drowning, and hypothermia. The underlying causes of death included injury-related, as well as respiratory and cardiac-related natural diseases. The time spent on ECMO varied from less than 1 h to 10 months. Complications encountered due to ECMO included cannulation site bleeding, pneumohemopericardium, retroperitoneal hematoma, limb ischemia, clotting, and cannula dislodgement. The patient population likely to receive ECMO has significant overlap with death circumstances likely to be reported to the medical examiner. As ECMO therapy has become increasingly available, it is of importance for medical examiners and death investigators to be familiar with the procedure as well as its limitations. Familiarity with ECMO and its sequelae allows for the proper documentation of postmortem findings and fosters an informed determination of the cause and manner of death.