Mechanical ventilation during extracorporeal membrane oxygenation support - New trends and continuing challenges.

BACKGROUND: The impact of mechanical ventilation on the survival of patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) due to severe acute respiratory distress syndrome (ARDS) remains still a focus of research. METHODS: Recent guidelines, randomized trials, and registry data underscore the importance of lung-protective ventilation during respiratory and cardiac support on ECMO. RESULTS: This approach includes decreasing mechanical power delivery by reducing tidal volume and driving pressure as much as possible, using low or very low respiratory rate, and a personalized approach to positive-end expiratory pressure (PEEP) setting. Notably, the use of ECMO in awake and spontaneously breathing patients is increasing, especially as a bridging strategy to lung transplantation. During respiratory support in V-V ECMO, native lung function is of highest importance and adjustments of blood flow on ECMO, or ventilator settings significantly impact the gas exchange. These interactions are more complex in veno-arterial (V-A) ECMO configuration and cardiac support. The fraction on delivered oxygen in the sweep gas and sweep gas flow rate, blood flow per minute, and oxygenator efficiency have an impact on gas exchange on device side. On the patient side, native cardiac output, native lung function, carbon dioxide production (VCO2), and oxygen consumption (VO2) play a role. Avoiding pulmonary oedema includes left ventricle (LV) distension monitoring and prevention, pulse pressure >10 mm Hg and aortic valve opening assessment, higher PEEP adjustment, use of vasodilators, ECMO flow adjustment according to the ejection fraction, moderate use of inotropes, diuretics, or venting strategies as indicated and according to local expertise and resources. CONCLUSION: Understanding the physiological principles of gas exchange during cardiac support on femoro-femoral V-A ECMO configuration and the interactions with native gas exchange and haemodynamics are essential for the safe applications of these techniques in clinical practice. Proning during ECMO remains to be discussed until further data is available from prospective, randomized trials implementing individualized PEEP titration during proning.

Association Between Body Mass Index and Outcomes in Venoarterial Extracorporeal Membrane Oxygenation.

BACKGROUND: The association between obesity, or elevated body mass index (BMI), and outcomes in patients receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO) has not been well established. Recent studies in patients receiving venovenous ECMO did not detect an association between obesity and increased mortality. The purpose of this retrospective observational study is to evaluate the association between BMI and survival in patients receiving VA-ECMO for cardiogenic shock. METHODS: All patients >18 years of age supported on VA-ECMO for refractory cardiogenic shock in a single academic center between 2009 and 2019 were included. ECMO outcomes, including successful ECMO decannulation and 30-day survival, were analyzed after stratification according to BMI. Multivariable and univariate logistic regression were used to assess the association between BMI and VA-ECMO outcomes. RESULTS: Of the total patients (n = 355) cannulated for VA-ECMO, 61.7% of the patients survived to ECMO recovery/decannulation, 45.5% of the patients survived to 30 days after ECMO decannulation, and 38.9% of the patients survived to hospital discharge with no statistically significant differences among the BMI groups. Multivariable logistic regression did not reveal any associations between obesity as defined by BMI and survival to ECMO decannulation (odds ratio [OR] 1.07 per 5 unit increase in BMI, 95% confidence interval [CI], 0.86-1.33; P = .57), 30-day survival (OR = 0.91, 95% CI, 0.73-1.14; P = .41) or survival to hospital discharge (OR = 0.95, 95% CI, 0.75-1.20; P = .66). CONCLUSIONS: Despite potential challenges to cannulation and maintaining adequate flow during ECMO, this single centered, retrospective observational study did not detect association between BMI and survival to ECMO decannulation, 30-day survival, or survival to hospital discharge for patients requiring VA-ECMO for refractory cardiogenic shock. These data suggest that obesity alone should not exclude candidacy for VA-ECMO.The primary outcome in this retrospective study was survival of the ECMO therapy (survival to ECMO decannulation), defined as surviving >24 hours after decannulation without a withdrawal of care. Secondary outcomes included survival at 30 days and survival to hospital discharge.

A walk through the progression of resuscitation medicine.

Cardiac arrest (CA) is a sudden and devastating disease process resulting in more deaths in the United States than many cancers, metabolic diseases, and even car accidents. Despite such a heavy mortality burden, effective treatments have remained elusive. The past century has been productive in establishing the guidelines for resuscitation, known as cardiopulmonary resuscitation (CPR), as well as developing a scientific field whose aim is to elucidate the underlying mechanisms of CA and develop therapies to save lives. CPR has been successful in reinitiating the heart after arrest, enabling a survival rate of approximately 10% in out-of-hospital CA. Although current advanced resuscitation methods, including hypothermia and extracorporeal membrane oxygenation, have improved survival in some patients, they are unlikely to significantly improve the national survival rate any further without a paradigm shift. Such a change is possible with sustained efforts in the basic and clinical sciences of resuscitation and their implementation. This review seeks to discuss the current landscape in resuscitation medicine-how we got here and where we are going.

Evolving outcomes of extracorporeal membrane oxygenation support for severe COVID-19 ARDS in Sorbonne hospitals, Paris.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) was frequently used to treat patients with severe coronavirus disease-2019 (COVID-19)-associated acute respiratory distress (ARDS) during the initial outbreak. Care of COVID-19 patients evolved markedly during the second part of 2020. Our objective was to compare the characteristics and outcomes of patients who received ECMO for severe COVID-19 ARDS before or after July 1, 2020. METHODS: We included consecutive adults diagnosed with COVID-19 in Paris-Sorbonne University Hospital Network ICUs, who received ECMO for severe ARDS until January 28, 2021. Characteristics and survival probabilities over time were estimated during the first and second waves. Pre-ECMO risk factors predicting 90-day mortality were assessed using multivariate Cox regression. RESULTS: Characteristics of the 88 and 71 patients admitted, respectively, before and after July 1, 2020, were comparable except for older age, more frequent use of dexamethasone (18% vs. 82%), high-flow nasal oxygenation (19% vs. 82%) and/or non-invasive ventilation (7% vs. 37%) after July 1. Respective estimated probabilities (95% confidence intervals) of 90-day mortality were 36% (27-47%) and 48% (37-60%) during the first and the second periods. After adjusting for confounders, probability of 90-day mortality was significantly higher for patients treated after July 1 (HR 2.27, 95% CI 1.02-5.07). ECMO-related complications did not differ between study periods. CONCLUSIONS: 90-day mortality of ECMO-supported COVID-19-ARDS patients increased significantly after July 1, 2020, and was no longer comparable to that of non-COVID ECMO-treated patients. Failure of prolonged non-invasive oxygenation strategies before intubation and increased lung damage may partly explain this outcome.

Extracorporeal membrane oxygenation for COVID-19: evolving outcomes from the international Extracorporeal Life Support Organization Registry.

BACKGROUND: Over the course of the COVID-19 pandemic, the care of patients with COVID-19 has changed and the use of extracorporeal membrane oxygenation (ECMO) has increased. We aimed to examine patient selection, treatments, outcomes, and ECMO centre characteristics over the course of the pandemic to date. METHODS: We retrospectively analysed the Extracorporeal Life Support Organization Registry and COVID-19 Addendum to compare three groups of ECMO-supported patients with COVID-19 (aged ≥16 years). At early-adopting centres-ie, those using ECMO support for COVID-19 throughout 2020-we compared patients who started ECMO on or before May 1, 2020 (group A1), and between May 2 and Dec 31, 2020 (group A2). Late-adopting centres were those that provided ECMO for COVID-19 only after May 1, 2020 (group B). The primary outcome was in-hospital mortality in a time-to-event analysis assessed 90 days after ECMO initiation. A Cox proportional hazards model was fit to compare the patient and centre-level adjusted relative risk of mortality among the groups. FINDINGS: In 2020, 4812 patients with COVID-19 received ECMO across 349 centres within 41 countries. For early-adopting centres, the cumulative incidence of in-hospital mortality 90 days after ECMO initiation was 36·9% (95% CI 34·1-39·7) in patients who started ECMO on or before May 1 (group A1) versus 51·9% (50·0-53·8) after May 1 (group A2); at late-adopting centres (group B), it was 58·9% (55·4-62·3). Relative to patients in group A2, group A1 patients had a lower adjusted relative risk of in-hospital mortality 90 days after ECMO (hazard ratio 0·82 [0·70-0·96]), whereas group B patients had a higher adjusted relative risk (1·42 [1·17-1·73]). INTERPRETATION: Mortality after ECMO for patients with COVID-19 worsened during 2020. These findings inform the role of ECMO in COVID-19 for patients, clinicians, and policy makers. FUNDING: None.

To prone or not to prone ARDS patients on ECMO.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2021. Other selected articles can be found online at  https://www.biomedcentral.com/collections/annualupdate2021 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from  https://link.springer.com/bookseries/8901 .

Chronic respiratory disease and survival outcomes after extracorporeal membrane oxygenation.

BACKGROUND: Quality of life following extracorporeal membrane oxygenation (ECMO) therapy is an important health issue. We aimed to describe the characteristics of patients who developed chronic respiratory disease (CRD) following ECMO therapy, and investigate the association between newly diagnosed post-ECMO CRDs and 5-year all-cause mortality among ECMO survivors. METHODS: We analyzed data from the National Health Insurance Service in South Korea. All adult patients who underwent ECMO therapy in the intensive care unit between 2006 and 2014 were included. ECMO survivors were defined as those who survived for 365 days after ECMO therapy. Chronic obstructive pulmonary disease (COPD), asthma, interstitial lung disease, lung cancer, lung disease due to external agents, obstructive sleep apnea, and lung tuberculosis were considered as CRDs. RESULTS: A total of 3055 ECMO survivors were included, and 345 (11.3%) were newly diagnosed with CRDs 365 days after ECMO therapy. The prevalence of asthma was the highest at 6.1% (185). In the multivariate logistic regression, ECMO survivors who underwent ECMO therapy for acute respiratory distress syndrome (ARDS) or respiratory failure had a 2.00-fold increase in post-ECMO CRD (95% confidence interval [CI]: 1.39 to 2.89; P < 0.001). In the multivariate Cox regression, newly diagnosed post-ECMO CRD was associated with a 1.47-fold (95% CI: 1.17 to 1.86; P = 0.001) higher 5-year all-cause mortality. CONCLUSIONS: At 12 months after ECMO therapy, 11.3% of ECMO survivors were newly diagnosed with CRDs. Patients who underwent ECMO therapy for ARDS or respiratory failure were associated with a higher incidence of newly diagnosed post-ECMO CRD compared to those who underwent ECMO for other causes. Additionally, post-ECMO CRDs were associated with a higher 5-year all-cause mortality. Our results suggest that ECMO survivors with newly diagnosed post-ECMO CRD might be a high-risk group requiring dedicated interventions.

Ethics in extracorporeal life support: a narrative review.

During 50 years of extracorporeal life support (ECLS), this highly invasive technology has left a considerable imprint on modern medicine, and it still confronts researchers, clinicians and policymakers with multifarious ethical challenges. After half a century of academic discussion about the ethics of ECLS, it seems appropriate to review the state of the argument and the trends in it. Through a comprehensive literature search on PubMed, we identified three ethical discourses: (1) trials and evidence accompanying the use of ECLS, (2) ECLS allocation, decision-making and limiting care, and (3) death on ECLS and ECLS in organ donation. All included articles were carefully reviewed, arguments extracted and grouped into the three discourses. This article provides a narrative synthesis of these arguments, evaluates the opportunities for mediation and substantiates the necessity of a shared decision-making approach at the limits of medical care.

A Core Outcome Set for Research in Patients on Extracorporeal Membrane Oxygenation.

OBJECTIVES: A core set of outcomes have been identified and published, which are essential to include in all clinical research evaluating the use of extracorporeal membrane oxygenation in critically ill patients, particularly regarding safety and adverse events. The purpose of this international modified Delphi study was to determine which measurement tools and the timing of measurement should be selected for the core outcome set for research evaluating patients receiving extracorporeal membrane oxygenation. DESIGN: This was a two-round international, multidisciplinary web-based, modified Delphi study. PATIENTS: Participants were identified from the International Extracorporeal Membrane Oxygenation Network and the Extracorporeal Life Support Organization, including consumers, multidisciplinary clinicians, researchers and industry partners. MEASUREMENTS: Measurement tools and the timing of measurement were identified from a systematic review of the literature and clinical trials registrations. The primary outcome was the percentage of respondents who completed each survey and indicated that a measurement tool as well as the timing of the measurement should "always" be included in a core outcome set. MAIN RESULTS: Participant response rates were 46 of 65 (71%) and 40 of 46 (87%) for rounds one and two, respectively, with participants representing, researchers, consumers, and industry partners from 15 countries over five continents. Seven measurement tools were identified for the core outcome set of patients on extracorporeal membrane oxygenation. CONCLUSIONS: This study has identified appropriate measurement instruments and the timing of measurement to include in the core outcome set for research evaluating patients receiving extracorporeal membrane oxygenation. This was an important final step to standardize and synthesize research efforts internationally.

Venoarterial Extracorporeal Membrane Oxygenation for Postcardiotomy Shock-Analysis of the Extracorporeal Life Support Organization Registry.

OBJECTIVES: Refractory postcardiotomy cardiogenic shock complicating cardiac surgery yields nearly 100% mortality when untreated. Use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock has increased worldwide recently. The aim of the current analysis was to outline the trends in use, changing patient profiles, and in-hospital outcomes including complications in patients undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. DESIGN: Analysis of extracorporeal life support organization registry from January 2010 to December 2018. SETTING: Multicenter worldwide registry. PATIENTS: Seven-thousand one-hundred eighty-five patients supported with venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. INTERVENTIONS: Venoarterial extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Hospital death, weaning from extracorporeal membrane oxygenation, hospital complications. Mortality predictors were assessed by multivariable logistic regression. Propensity score matching was performed for comparison of peripheral and central cannulation for extracorporeal membrane oxygenation. A significant trend toward more extracorporeal membrane oxygenation use in recent years (coefficient, 0.009; p < 0.001) was found. Mean age was 56.3 ± 14.9 years and significantly increased over time (coefficient, 0.513; p < 0.001). Most commonly, venoarterial extracorporeal membrane oxygenation was instituted after coronary artery bypass surgery (26.8%) and valvular surgery (25.6%), followed by heart transplantation (20.7%). Overall, successful extracorporeal membrane oxygenation weaning was possible in 4,520 cases (56.4%), and survival to hospital discharge was achieved in 41.7% of cases. In-hospital mortality rates remained constant over time (coefficient, -8.775; p = 0.682), whereas complication rates were significantly reduced (coefficient, -0.009; p = 0.003). Higher mortality was observed after coronary artery bypass surgery (65.4%), combined coronary artery bypass surgery with valve (68.4%), and aortic (69.6%) procedures than other indications. Lower mortality rates were observed in heart transplantation recipients (46.0%). Age (p < 0.001), central cannulation (p < 0.001), and occurrence of complications while on extracorporeal membrane oxygenation were independently associated with poorer prognosis. CONCLUSIONS: The analysis confirmed increased use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. Mortality rates remained relatively constant over time despite a decrease in complications, in the setting of supporting older patients.

Use of Mechanical Circulatory Support Devices Among Patients With Acute Myocardial Infarction Complicated by Cardiogenic Shock.

Importance: Mechanical circulatory support (MCS) devices, including intravascular microaxial left ventricular assist devices (LVADs) and intra-aortic balloon pumps (IABPs), are used in patients who undergo percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) complicated by cardiogenic shock despite limited evidence of their clinical benefit. Objective: To examine trends in the use of MCS devices among patients who underwent PCI for AMI with cardiogenic shock, hospital-level use variation, and factors associated with use. Design, Setting, and Participants: This cross-sectional study used the CathPCI and Chest Pain-MI Registries of the American College of Cardiology National Cardiovascular Data Registry. Patients who underwent PCI for AMI complicated by cardiogenic shock between October 1, 2015, and December 31, 2017, were identified from both registries. Data were analyzed from October 2018 to August 2020. Exposures: Therapies to provide hemodynamic support were categorized as intravascular microaxial LVAD, IABP, TandemHeart, extracorporeal membrane oxygenation, LVAD, other devices, combined IABP and intravascular microaxial LVAD, combined IABP and other device (defined as TandemHeart, extracorporeal membrane oxygenation, LVAD, or another MCS device), or medical therapy only. Main Outcomes and Measures: Use of MCS devices overall and specific MCS devices, including intravascular microaxial LVAD, at both patient and hospital levels and variables associated with use. Results: Among the 28 304 patients included in the study, the mean (SD) age was 65.4 (12.6) years and 18 968 were men (67.0%). The overall MCS device use was constant from the fourth quarter of 2015 to the fourth quarter of 2017, although use of intravascular microaxial LVADs significantly increased (from 4.1% to 9.8%; P < .001), whereas use of IABPs significantly decreased (from 34.8% to 30.0%; P < .001). A significant hospital-level variation in MCS device use was found. The median (interquartile range [IQR]) proportion of patients who received MCS devices was 42% (30%-54%), and the median proportion of patients who received intravascular microaxial LVADs was 1% (0%-10%). In multivariable analyses, cardiac arrest at first medical contact or during hospitalization (odds ratio [OR], 1.82; 95% CI, 1.58-2.09) and severe left main and/or proximal left anterior descending coronary artery stenosis (OR, 1.36; 95% CI, 1.20-1.54) were patient characteristics that were associated with higher odds of receiving intravascular microaxial LVADs only compared with IABPs only. Conclusions and Relevance: This study found that, among patients who underwent PCI for AMI complicated by cardiogenic shock, overall use of MCS devices was constant, and a 2.5-fold increase in intravascular microaxial LVAD use was found along with a corresponding decrease in IABP use and a significant hospital-level variation in MCS device use. These trends were observed despite limited clinical trial evidence of improved outcomes associated with device use.

Pediatric and neonatal extracorporeal life support: current state and continuing evolution.

The use of extracorporeal life support (ECLS) for the pediatric and neonatal population continues to grow. At the same time, there have been dramatic improvements in the technology and safety of ECLS that have broadened the scope of its application. This article will review the evolving landscape of ECLS, including its expanding indications and shrinking contraindications. It will also describe traditional and hybrid cannulation strategies as well as changes in circuit components such as servo regulation, non-thrombogenic surfaces, and paracorporeal lung-assist devices. Finally, it will outline the modern approach to managing a patient on ECLS, including anticoagulation, sedation, rehabilitation, nutrition, and staffing.

Early venoarterial extracorporeal membrane oxygenation improves outcomes in post-cardiotomy shock.

Post-cardiotomy shock (PCS) is associated with substantial morbidity and mortality. We reviewed our 12-year experience of venoarterial extracorporeal membrane oxygenation (VA-ECMO) therapy for PCS. Between July 2007 and June 2018, 156 consecutive patients underwent VA-ECMO for PCS. We retrospectively investigated patient characteristics, indications, and management to determine factors affecting outcomes. Secondary analysis was performed by dividing the cohort into Era 1 (2007-2012, n = 52) and Era 2 (2013-2018, n = 104) for comparison. After a median of 4.70 days (interquartile range [IQR] 2.76-8.53) of ECMO support, 72 patients (46.1%) survived to discharge. In-hospital mortality decreased in Era 2 from 75 to 43.3% (P < 0.001). Survivors were cannulated at lower serum lactate (5.3 [IQR 2.8-8.2] versus 7.5 [4.7-10.7], P = 0.003) and vasoactive-inotropic score (22.7 [IQR 11.3-35.5] versus 28.1 [IQR 20.8-42.5], P = 0.017). Patients in Era 2 were more frequently cannulated intraoperatively (63.5% versus 34.6%, P = 0.002), earlier in their hospital course, and at lower levels of serum lactate and vasoactive-inotropic score than in Era 1. Independent risk factors for mortality included increased age (odds ratio [OR] 1.06, P = 0.002), serum lactate at cannulation (OR 1.17, P = 0.009), and vasoactive-inotropic score (OR 1.04, P = 0.009). Bleeding and limb ischemia were less common in Era 2. Overall, outcomes of ECMO for PCS improved over the study period. The survival benefit appears to be associated with earlier ECMO initiation before prolonged hypoperfusion occurs.

Cardiogenic shock: incidence, survival and mechanical circulatory support usage 2007-2017-insights from a national registry.

BACKGROUND: A central element in the management of cardiogenic shock (CS) comprises mechanical circulatory support (MCS) systems to maintain cardiac output (CO). This study aims to quantify incidence, outcome and influence of MCS in CS over the last decade. METHODS: All patients hospitalized with CS in a tertiary university hospital in Germany between 2007 and 2017 were identified utilizing the international coding system ICD-10 with code R57.0. Application of MCS was identified via German procedure classification codes (OPS). RESULTS: 383,983 cases of cardiogenic shock were reported from 2007 to 2017. Patients had a mean age of 71 years and 38.5% were female. The incidence of CS rose by 65.6% from 26,828 cases in 2007 (33.1 per 100,000 person-years, hospital survival 39.2%) to 44,425 cases in 2017 (53.7 per 100,000 person-years, survival 41.2%). In 2007, 16.0% of patients with CS received MCS (4.6 per 100,000 person-years, survival 46.6%), dropping to 13.9% in 2017 (6.6 per 100,000 person-years, survival 38.6%). Type of MCS changed over the years, with decreasing use of the intra-aortic balloon pump (IABP), an increase in extracorporeal membrane oxygenation (VA-ECMO) and percutaneous ventricular assist device (pVAD) usage. Significant differences regarding in-hospital survival were observed between the devices (survival: overall: 40.2%; medical treatment = 39.5%; IABP = 49.5%; pVAD = 36.2%; VA-ECMO = 30.5%; p < 0.001). CONCLUSIONS: The incidence of CS is increasing, but hospital survival remains low. MCS was used in a minority of patients, and the percentage of MCS usage in CS has decreased. The use rates of the competing devices change over time.

Trends in Extracorporeal Membrane Oxygenation Application and Outcomes in Korea.

The use of extracorporeal membrane oxygenation (ECMO) is increasing despite the limited evidence in survival benefit. This study aimed to analyze the changes of in-hospital mortality, medical costs, and other outcomes in ECMO therapy. We used 2004-2017 data from a nationwide healthcare administrative claims database in Korea. Overall, 14,775 ECMO procedures were performed in 14,689 patients at 112 hospitals. We found a 170-fold and a 334-fold increase in the number of ECMO procedures and related costs, respectively. For indications, the performance of ECMO for heart or lung transplantation and respiratory failure increased, whereas that for cardiovascular surgery decreased. The duration of ECMO increased from a median of 3 days (IQR, 2-5 days) in 2004 to 4 days (IQR, 2-9 days) in 2017. The overall in-hospital mortality rate was 68.6%, and this improved over time, especially for lung transplantation and respiratory failure patients. Bleeding-related complications and the transfusion amount also decreased. Hospitals with higher case volume showed better survival outcomes. The median cost per procedure and per day was 26,538 USD (IQR, 14,646-47,862 USD) and 1,560 USD (IQR, 903-2,929 USD), respectively, and increased with time. A trend toward greater resource use and better outcomes requires additional cost-effective analysis based on indications.