Validation of Prognostic Scores in Extracorporeal Life Support: A Multi-Centric Retrospective Study

Vasoactive-Inotropic Score as a Promising Predictor of Acute Kidney Injury in Adult Patients Requiring Extracorporeal Membrane Oxygenation

Acute kidney injury (AKI) is a common complication in patients supported by extracorporeal membrane oxygenation (ECMO). Vasoactive-Inotropic Score (VIS) serves as an indicator of the extent of cardiovascular drug support provided. Our objective is to assess the relationship between the VIS and ECMO-associated AKI (EAKI). This single-center retrospective study extracted adult patients treated with ECMO between August 2016 and September 2022 from an intensive care unit (ICU) in a university hospital. A total of 126 patients requiring ECMO support were included in the study, of which 76% developed AKI. Multivariate logistic regression analysis identified VIS-max Day1 (odds ratio [OR]: 1.025, 95% confidence interval [CI]: 1.007-1.044, p = 0.006), VIS-max Day2 (OR: 1.038, 95% CI: 1.007-1.069, p = 0.015), VIS-mean Day1 (OR: 1.048, 95% CI: 1.013-1.084, p = 0.007), and VIS-mean Day2 (OR: 1.059, 95% CI: 1.014-1.107, p = 0.010) as independent risk factors for EAKI. VIS-max Day1 showing the best predictive effect (Area under the receiver operating characteristic curve (AUROC): 0.80, sensitivity: 71.87%, specificity: 80.00%) for EAKI with a cutoff value of 33.33. Surprisingly, VIS-mean Day2 was also excellent at predicting 7 day mortality (AUROC: 0.77, sensitivity: 87.50%, specificity: 56.38%) with a cutoff value of 8.67. In conclusion, VIS could independently predict EAKI and 7 day mortality in patients with ECMO implantation, which may help clinicians to recognize the poor prognosis in time for early intervention.

Prevalence and risk factors for in-hospital mortality of adult patients on veno-arterial extracorporeal membrane oxygenation for cardiogenic shock and cardiac arrest: A systematic review and meta-analysis

OBJECTIVES

To synthesize quantitative research findings on the prevalence and risk factors for in-hospital mortality of patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

A comprehensive search was conducted for the period from May 2008 to December 2023 by searching the five electronic databases of PubMed, CINAHL, Web of Science, EMBASE, and Cochrane library. The quality of included studies was assessed using the Newcastle-Ottawa scale. The meta-analysis estimated the pooled odds ratio or standard mean difference and 95% confidence intervals.

RESULTS

A total of twenty-five studies with 10,409 patients were included in the analysis. The overall in-hospital mortality of patients on VA-ECMO was 56.7 %. In the subgroup analysis, in-hospital mortality of VA-ECMO for cardiogenic shock and cardiac arrest was 49.2 % and 75.2 %, respectively. The number of significant factors associated with an increased risk of in-hospital mortality in the pre-ECMO period (age, body weight, creatinine, chronic kidney disease, pH, and lactic acid) was greater than that in the intra- and post-ECMO periods. Renal replacement, bleeding, and lower limb ischemia were the most significant risk factors for in-hospital mortality in patients receiving VA-ECMO.

CONCLUSION

Early detection of the identified risk factors can contribute to reducing in-hospital mortality in patients on VA-ECMO. Intensive care unit nurses should provide timely and appropriate care before, during, and after VA-ECMO.

IMPLICATIONS FOR CLINICAL PRACTICE

Intensive care unit nurses should be knowledgeable about factors associated with the in-hospital mortality of patients on VA-ECMO to improve outcomes. The present findings may contribute to developing guidelines for reducing in-hospital mortality among patients considering ECMO.

Non-invasive assessment of left ventricular contractility by myocardial work index in veno-arterial membrane oxygenation patients: rationale and design of the MIX-ECMO multicentre observational study

Introduction and aims

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an increasingly utilized therapeutic choice in patients with cardiogenic shock, however, high complication rate often counteracts with its beneficial cardiopulmonary effects. The assessment of left ventricular (LV) function in key in the management of this population, however, the most commonly used measures of LV performance are substantially load-dependent. Non-invasive myocardial work is a novel LV functional measure which may overcome this limitation and estimate LV function independent of the significantly altered loading conditions of VA-ECMO therapy. The Usefulness of Myocardial Work IndeX in ExtraCorporeal Membrane Oxygenation Patients (MIX-ECMO) study aims to examine the prognostic role of non-invasive myocardial work in VA-ECMO-supported patients.

Methods

The MIX-ECMO is a multicentric, prospective, observational study. We aim to enroll 110 patients 48-72 h after the initiation of VA-ECMO support. The patients will undergo a detailed echocardiographic examination and a central echocardiography core laboratory will quantify conventional LV functional measures and non-invasive myocardial work parameters. The primary endpoint will be failure to wean at 30 days as a composite of cardiovascular mortality, need for long-term mechanical circulatory support or heart transplantation at 30 days, and besides that other secondary objectives will also be investigated. Detailed clinical data will also be collected to compare LV functional measures to parameters with established prognostic role and also to the Survival After Veno-arterial-ECMO (SAVE) score.

Conclusions

The MIX-ECMO study will be the first to determine if non-invasive myocardial work has added prognostic value in patients receiving VA-ECMO support.

What Are the Real Issues in Providing Extracorporeal Membrane Oxygenation (ECMO) Support: A Survey

INTRODUCTION

By using a novel survey our study aimed to assess the challenges ECMO and Critical Care (CC) teams face when initiating and managing patient's ECMO support.

METHODS

A qualitative survey-based observational study was performed of members of 2 Critical Care Medicine organizations involved in decision-making around the practice of Extracorporeal Membrane Oxygenation (ECMO). The range of exploratory questions covered ethical principles of informed consent, autonomy and goals of care discussions, beneficence, non-maleficence (offering life-sustaining treatments in end-of-life care), and justice (insurance-related limitations of treatment). Questions also covered pragmatic practice and quality improvement areas, such as exploring whether palliative care or ethics teams were involved in such decision-making.

RESULTS

305 members received the survey links, and a total of 61 completed surveys were received, for an overall response rate of 20% among all eligible members. Only 70% of the participants who manage ECMO patients are involved in the ECMO initiation decision process. The majority do not involve Ethics or Palliative care at the initial ECMO initiation decision step. Of the ethical and moral dilemmas reported, the majority revolved around 1. Prognostication of patients receiving VV and VA ECMO support, 2. Lack of knowledge of patient's wishes and goals, 3. Disconnect between expectations of families and outcomes and 4. Staff moral distress around when to stop ECMO in case of futility.

CONCLUSION

Our survey highlights areas of distress and dilemma which have been stressed before in the initiation, management, and outcomes of ECMO patients, however with the increasing use of this modality of cardiopulmonary mechanical support being offered, the survey results can offer a guidance using sound ethical principles.

The Utility of Risk Scores in Postcardiotomy Extracorporeal Membrane Oxygenation

BACKGROUND

The use of a venoarterial extracorporeal membrane oxygenation (ECMO) in the postcardiotomy shock setting (PC-ECMO) can be life-saving. Risk stratification for patients under PC-ECMO is currently challenging. The aim of this study was to assess the discriminatory ability of the different available risk scores for mortality in PC-ECMO patients.

METHODS

Patients aged >18 years undergoing coronary artery bypass, valve surgery, or a combination of these procedures and implanted an ECMO for postcardiotomy shock between January 2017 and June 2022 in a single ELSO registered center were retrospectively included. The STS, Euroscore II, SAVE, modified SAVE, APACHE II, and VIS scores were compared for their discriminatory ability concerning weaning and 30-day survival.

RESULTS

During the study period, 7342 patients underwent coronary bypass or valve surgery, of whom 109 patients with PC-ECMO were included in the analysis. The Euroscore II and STS scores were not associated significantly with 30-day mortality, whereas the SAVE, the modified SAVE, APACHE II, and VIS scores significantly predicted 30-day mortality. The SAVE and the modified SAVE scores showed moderate discrimination ability with AUCs of 0.672 and 0.695, while the APACHE and VIS scores had a satisfactory discriminatory ability with AUCs of 0.727 and 0.844, respectively.

CONCLUSION

Currently used risk scores for PC-ECMO patients do not provide satisfactory predictions for weaning and survival. VIS at the 24th hour can be a valuable parameter for risk analysis and prospective studies can investigate novel PC-ECMO risk scoring systems.

Guide to Temporary Mechanical Support in Cardiogenic Shock: Choosing Wisely

Cardiogenic shock is a multisystem pathology that carries a high mortality rate, and initial pharmacotherapies include the use of vasopressors and inotropes. These agents can increase myocardial oxygen consumption and decrease tissue perfusion that can oftentimes result in a state of refractory cardiogenic shock for which temporary mechanical circulatory support can be considered. Numerous support devices are available, each with its own hemodynamic blueprint. Defining a patient's hemodynamic profile and understanding the phenotype of cardiogenic shock is important in device selection. Careful patient selection incorporating a multidisciplinary team approach should be utilized.

Prolonged VV ECMO: Navigating the Unchartered Sea

How to cite this article: Kumar V. Prolonged VV ECMO: Navigating the Unchartered Sea. Indian J Crit Care Med 2023;27(11):779-781.

Days spent on non-invasive ventilation support: can it determine when to initiate VV- ECMO? Observational study in a cohort of Covid-19 patients

BACKGROUND

The study evaluates the impact of the time between commencing non-invasive ventilation (NIV) support and initiation of venovenous extracorporeal membrane oxygenation (VV-ECMO) in a cohort of critically ill patients with coronavirus disease 2019 (COVID-19) associated acute respiratory distress syndrome (ARDS).

METHODS

Prospective observational study design in an intensive Care Unit (ICU) of a tertiary hospital in Barcelona (Spain). All patients requiring VV-ECMO support due to COVID-19 associated ARDS between March 2020 and January 2022 were analysed. Survival outcome was determined at 90 days after VV-ECMO initiation. Demographic data, comorbidities at ICU admission, RESP (respiratory ECMO survival prediction) score, antiviral and immunomodulatory treatments received, inflammatory biomarkers, the need for vasopressors, the thromboprophylaxis regimen received, and respiratory parameters including the length of intubation previous to ECMO and the length of each NIV support (high-flow nasal cannula, continuous positive airway pressure and bi-level positive airway pressure), were also collated in order to assess risk factors for day-90 mortality. The effect of the time lapse between NIV support and VV-ECMO on survival was evaluated using logistic regression and adjusting the association with all factors that were significant in the univariate analysis.

RESULTS

Seventy-two patients finally received VV-ECMO support. At 90 days after commencing VV-ECMO 35 patients (48%) had died and 37 patients (52%) were alive. Multivariable analysis showed that at VV-ECMO initiation, age (p = 0.02), lactate (p = 0.001), and days from initiation of NIV support to starting VV-ECMO (p = 0.04) were all associated with day-90 mortality.

CONCLUSIONS

In our small cohort of VV-ECMO patients with COVID-19 associated ARDS, the time spent between initiation of NIV support and VV-ECMO (together with age and lactate) appeared to be a better predictor of mortality than the time between intubation and VV-ECMO.

Nucleated red blood cells are a predictor of mortality in patients under extracorporeal membrane oxygenation

BACKGROUND

The presence of Nucleated Red Blood Cells (NRBCs) in critically ill patients is associated with higher mortality and poor prognosis. Although patients on extracorporeal support such as veno-venous or veno-arterial extracorporeal membrane oxygenation (VV/VA-ECMO) are severely ill, NRBCs have rarely been investigated regarding their predictive value so far.

METHODS

As part of a retrospective study, we examined all cardiothoracic surgery patients from July 2019 to September 2020 who received ECMO treatment during their inpatient stay. The aim of this study was to investigate the occurrence of NRBCs during ECMO support in terms of their predictive value for mortality.

RESULTS

In total 30 patients (age at admission: 62.7 ± 14.3 year; 26 male; ECMO duration: 8.5 ± 5.1 days; ICU duration: 18.0 ± 14.5 days) were included. 16 patients (53.3%) died during their inpatient stay. There were no significant differences in demographic characteristics between VA- or VV- ECMO patients. NRBCs occurred in all patients while under ECMO support. NRBC value was significant higher in those who died (2299.6 ± 4356.6 µl) compared to the surviving patients (133.6 ± 218.8 µl, p < 0.001). Univariate analysis found that patients with a cutoff value of ≥ 270 NRBCs/µl during ECMO support were 39 times more likely to die (OR 39.0, 95% CI 1.5-997.5, p < 0.001). 12 out of 13 patients (92.3%) with ≥ 270 NRBCs/µl died. The area under the curve (AUC) of the receiver operating characteristic curve was 0.85 (95% CI 0.69-0.96) with a sensitivity of 75.0% and a specificity of 92.9%.

CONCLUSION

NRBCs appear to be an accurate biomarker for mortality in patients with ECMO support. They may be helpful in deciding if therapy becomes futile. Trial registration DRKS00023626 (December 20th 2020).

Validation of the prognostic scoring system for inhospital mortality prediction in cardiogenic shock patients requiring venoarterial extracorporeal membrane oxygenation

BACKGROUND

A few prognostic scoring systems have been developed for predicting mortality in patients with cardiogenic shock requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO), albeit with variations in performance. This study aimed to assess and compare various mortality prediction models in a cohort of patients receiving VA-ECMO following cardiogenic shock or arrest.

METHODS

We retrospectively analyzed 77 patients with cardiogenic shock who were placed on VA-ECMO support between March 2014 and August 2021. The APACHE II, SAPS II, SAVE, Modified SAVE, ENCOURAGE, and ECMO-ACCEPTS scores were calculated for each patient to predict the in-hospital mortality.

RESULTS

Fifty-six (72.7%) patients died. All prediction model scores, except the ECMO-ACCEPTS, differed significantly between non-survivors and survivors as follows: ENCOURAGE, 23 versus 16 (p < 0.001); SAVE, -6 versus -3 (p = 0.008); Modified SAVE, -5 versus 0 (p = 0.005); APACHE II, 32 versus 22 (p = 0.009); and SAPS II, 67 versus 49 (p = 0.002). The ENCOURAGE score demonstrated the best discriminatory ability with an area under the receiver-operating characteristic curve of 0.81 (95% confidence interval: 0.7-0.81). All prognostic scoring systems possessed limited calibration ability. However, the SAPS II, SAVE, and ENCOURAGE scores had lower Akaike and Bayesian information criteria values, which were consistent with the results of the Hosmer-Lemeshow C statistic test, indicating better performance than the other scores.

CONCLUSIONS

The ENCOURAGE score can help predict in-hospital mortality in all subsets of VA-ECMO patients, even though it was originally designed to predict intensive care unit mortality in the post-acute myocardial infarction setting.

Predictive models in extracorporeal membrane oxygenation (ECMO): a systematic review

PURPOSE

Extracorporeal membrane oxygenation (ECMO) has been increasingly used in the last years to provide hemodynamic and respiratory support in critically ill patients. In this scenario, prognostic scores remain essential to choose which patients should initiate ECMO. This systematic review aims to assess the current landscape and inform subsequent efforts in the development of risk prediction tools for ECMO.

METHODS

PubMed, CINAHL, Embase, MEDLINE and Scopus were consulted. Articles between Jan 2011 and Feb 2022, including adults undergoing ECMO reporting a newly developed and validated predictive model for mortality, were included. Studies based on animal models, systematic reviews, case reports and conference abstracts were excluded. Data extraction aimed to capture study characteristics, risk model characteristics and model performance. The risk of bias was evaluated through the prediction model risk-of-bias assessment tool (PROBAST). The protocol has been registered in Open Science Framework ( https://osf.io/fevw5 ).

RESULTS

Twenty-six prognostic scores for in-hospital mortality were identified, with a study size ranging from 60 to 4557 patients. The most common candidate variables were age, lactate concentration, creatinine concentration, bilirubin concentration and days in mechanical ventilation prior to ECMO. Five out of 16 venous-arterial (VA)-ECMO scores and 3 out of 9 veno-venous (VV)-ECMO scores had been validated externally. Additionally, one score was developed for both VA and VV populations. No score was judged at low risk of bias.

CONCLUSION

Most models have not been validated externally and apply after ECMO initiation; thus, some uncertainty whether ECMO should be initiated still remains. It has yet to be determined whether and to what extent a new methodological perspective may enhance the performance of predictive models for ECMO, with the ultimate goal to implement a model that positively influences patient outcomes.

Major Bleeding and Thromboembolic Events in Veno-Venous Extracorporeal Membrane Oxygenation-Patients With Isolated Respiratory Failure

Bleeding and thromboembolic events are common during veno-venous extracorporeal membrane oxygenation (vvECMO). It is unknown whether these complications are driven by the ECMO system itself, multiorgan-failure, or both. The aim of this study was to assess the prevalence of bleeding and thromboembolic events in patients with isolated respiratory failure. Patients with vvECMO were retrospectively included from March 2009 to October 2017. Exclusion included any organ failure other than respiratory. Major bleeding was defined as a decrease in hemoglobin ≥2 g/dl per 24 hours, the requirement for transfusion of ≥2 packed red blood cell concentrates per 24 hours, any retroperitoneal, pulmonary, central nervous system bleeding, or bleeding requiring surgery. Thromboembolic events were assessed by duplex sonography or CT scan. Of 601 patients, 123 patients with a mean age of 49 ± 15 years and a median Sepsis-related Organ Failure Assessment score of 8 (7-9) were eligible for the analysis. Major bleeding was observed in 73%; 35% of all bleedings occurred on the day of or after ECMO initiation. A more pronounced decrease of PaCO2 after ECMO initiation was seen in patients with intracranial bleeding (ICB) compared with those without. Thromboembolic events were noted in 30%. The levels of activated prothrombin time, fibrinogen, platelet count, or D-dimers affected neither bleeding nor the prevalence of thromboembolic events.

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.

Arterial and venous vascular complications in patients requiring peripheral venoarterial extracorporeal membrane oxygenation

Introduction

The aim of this study was to investigate the prevalence of arterial and venous complications in patients requiring peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) and its risk factors at the time of cannulation and during extracorporeal membrane oxygenation (ECMO) support and to assess vascular complications in association with decannulation.

Material and methods

Between January 2010 to January 2020, out of 1,030 eligible patients requiring VA-ECMO, 427 with analyzable vascular screening were included. Duplex sonography and/or CT scan after decannulation were used to screen for thrombosis and pulmonary embolism as well as arterial complications. Near-infrared spectrometry (NIRS) was established at the time of cannulation and was continuously monitored during the ECMO therapy.

Results

The prevalence of venous complications was 27%. Thrombosis and pulmonary embolism were observed in 21 and 7% of patients, respectively. Pulmonary embolism was more frequently diagnosed in patients with thrombosis (22 vs. 3%, p &lt; 0.001). In multivariate analysis, cannulation in the jugular vein was determined as a risk factor for venous thrombosis in contrast to the extent of anticoagulation. The prevalence of arterial complications was 37%, mainly ischemia followed by bleeding, dissection, and compartment syndrome. Vascular surgery was necessary for 19% of the patients, of whome 1% required major amputations. A distal perfusion cannula (DPC) was implanted at cannulation in 24% of patients and secondarily in 16% of patients after cannulation as required during ECMO support. In the multivariate analysis, risk factors for leg ischemia at the time of cannulation were elevated D-dimers, lower NIRS on the cannulated leg, and lack of a DPC. The best discriminative parameter was the difference in NIRS between the non-cannulated leg and the cannulated leg. In contrast, during ECMO support, only the lack of a DPC was associated with leg ischemia. A similar rate of complications associated with decannulation, mainly arterial thrombosis, ischemia, or bleeding, was seen with percutaneous and surgical approaches (18 vs. 17%, p = 0.295).

Conclusion

Patients requiring VA ECMO should be routinely screened for vascular complications. The decision to insert a DPC should be evaluated individually. However, NIRS monitoring of the cannulated leg and the non-cannulated leg is essential to identify the legs at risk for critical ischemia. As complications associated with decannulation were equally distributed between percutaneous and surgical approaches, the applied method may be chosen according to local experience.

A Comprehensive Appraisal of Risk Prediction Models for Cardiogenic Shock

ABSTRACT

Despite advances in early revascularization, percutaneous hemodynamic support platforms, and systems of care, cardiogenic shock (CS) remains associated with a mortality rate higher than 50%. Several risk stratification models have been derived since the 1990 s to identify patients at high risk of adverse outcomes. Still, limited information is available on the differences between scoring systems and their relative applicability to both acute myocardial infarction and advanced decompensated heart failure CS. Thus, we reviewed the similarities, differences, and limitations of published CS risk prediction models and herein discuss their suitability to the contemporary management of CS care.

Vasoactive Inotropic Score as a Prognostic Factor during (Cardio-) Respiratory ECMO

The vasoactive inotropic score (VIS) is calculated as a weighted sum of all administered vasopressor and inotropic medications and quantifies the amount of pharmacological cardiovascular support in patients with the most severe combined cardiopulmonary failure supported with extracorporeal membrane oxygenation (ECMO). This study evaluated (1) whether VIS prior to the initiation of ECMO is an independent predictor of survival in these patients and (2) whether VIS might guide the selection of the appropriate extracorporeal cannulation modality (Veno-Venous ‘V-V’ or Veno-VenoArterial ‘V-VA’). In this study, 39 V-VA and 182 V-V ECMO runs were retrospectively analyzed. VIS immediately prior to ECMO initiation (pre-ECMO) was 40 (10/113) in all patients, 30 (10/80) in patients with V-V ECMO and 207 (60/328) in patients with V-VA ECMO. Pre-ECMO VIS was an independent predictor of survival in univariate (AUC = 0.68, p = 0.001) and multi-variable analyses (p = 0.02). Pre-ECMO VIS was clearly associated with mortality (p = 0.001) in V-V ECMO group; however, V-VA ECMO disrupted this association (p = 0.18). Therefore, in conjunction with echocardiography, VIS might assist in selecting the appropriate ECMO cannulation strategy as patients with a pre-ECMO VIS ≥ 61.4 had significantly lower odds of survival compared to those with lower VIS.

Contraindications to the Initiation of Veno-Venous ECMO for Severe Acute Respiratory Failure in Adults: A Systematic Review and Practical Approach Based on the Current Literature

(1) Background: Extracorporeal membrane oxygenation (ECMO) is increasingly used for acute respiratory failure with few absolute but many relative contraindications. The provider in charge often has a difficult time weighing indications and contraindications to anticipate if the patient will benefit from this treatment, a decision that often decides life and death for the patient. To assist in this process in coming to a good evidence-based decision, we reviewed the available literature. (2) Methods: We performed a systematic review through a literature search of the MEDLINE database of former and current absolute and relative contraindications to the initiation of ECMO treatment. (3) Results: The following relative and absolute contraindications were identified in the literature: absolute-refusal of the use of extracorporeal techniques by the patient, advanced stage of cancer, fatal intracerebral hemorrhage/cerebral herniation/intractable intracranial hypertension, irreversible destruction of the lung parenchyma without the possibility of transplantation, and contraindications to lung transplantation; relative-advanced age, immunosuppressed patients/pharmacological immunosuppression, injurious ventilator settings > 7 days, right-heart failure, hematologic malignancies, especially bone marrow transplantation and graft-versus-host disease, SAPS II score ≥ 60 points, SOFA score > 12 points, PRESERVE score ≥ 5 points, RESP score ≤ -2 points, PRESET score ≥ 6 points, and "do not attempt resuscitation" order (DN(A)R status). (4) Conclusions: We provide a simple-to-follow algorithm that incorporates absolute and relative contraindications to the initiation of ECMO treatment. This algorithm attempts to weigh pros and cons regarding the benefit for an individual patient and hopefully assists caregivers to make better, informed decisions.

Awake Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: Which Clinical Issues Should Be Taken Into Consideration

With the goal of protecting injured lungs and extrapulmonary organs, venovenous extracorporeal membrane oxygenation (VV-ECMO) has been increasingly adopted as a rescue therapy for patients with severe acute respiratory distress syndrome (ARDS) when conventional mechanical ventilation failed to provide effective oxygenation and decarbonation. In recent years, it has become a promising approach to respiratory support for awake, non-intubated, spontaneously breathing patients with respiratory failure, referred to as awake ECMO, to avoid possible detrimental effects associated with intubation, mechanical ventilation, and the adjunctive therapies. However, several complex clinical issues should be taken into consideration when initiating and implementing awake ECMO, such as selecting potential patients who appeared to benefit most; techniques to facilitating cannulation and maintain stable ECMO blood flow; approaches to manage pain, agitation, and delirium; and approaches to monitor and modulate respiratory drive. It is worth mentioning that there had also been some inherent disadvantages and limitations of awake ECMO compared to the conventional combination of ECMO and invasive mechanical ventilation. Here, we review the use of ECMO in awake, spontaneously breathing patients with severe ARDS, highlighting the issues involving bedside clinical practice, detailing some of the technical aspects, and summarizing the initial clinical experience gained over the past years.