Extracorporeal membrane oxygenation in patients with severe respiratory failure from COVID-19

Venovenous extracorporeal membrane oxygenation for COVID-19 associated severe respiratory failure: Case series from a Hungarian tertiary centre

INTRODUCTION

Venovenous extracorporeal membrane oxygenation (V-V ECMO) is recommended for the support of patients with severe COVID-19 associated severe respiratory failure (SRF). We report the characteristics and outcome of COVID-19 patients supported with V-V ECMO in a Hungarian centre.

METHODS

We retrospectively collected data on all patients admitted with proven SARS CoV-2 infection who received V-V ECMO support between March 2021 and May 2022.

RESULTS

Eighteen patients were placed on ECMO during this period, (5 women, age (mean ± SD) 44 ± 10 years, APACHE II score (median (interquartile range)) 12 (10-14.5)). Before ECMO support, they had been hospitalised for 6 (4-11) days. Fifteen patients received noninvasive ventilation for 4 (2-8) days, two patients had high flow nasal oxygen therapy, for one day each. They had already been intubated for 2.5 (1-6) days. Prone position was applied in 15 cases. On the day before ECMO initiation the Lung Injury Score was 3.25 (3-3.26), the PaO2/FiO2 ratio was 71 ± 19 mmHg. The duration of V-V ECMO support was 26 ± 20 days, and the longest run lasted 70 days. Patients were mechanically ventilated for 34 ± 23 days. The intensive care unit (ICU) and the hospital length of stay were 40 ± 28 days and 45 ± 31 days, respectively. Eleven patients were successfully weaned from ECMO. The ICU survival rate was 56%, the in-hospital survival was 50%. All patients who were discharged from hospital reported a good health-related quality of life Rankin score (0-2) at the 5-16 months follow-up.

CONCLUSIONS

During the last three waves of the COVID-19 pandemic, we achieved a 56% ICU and a 50% hospital survival rate at our low volume centre.

Impact of Coronavirus Disease 2019 Pandemic on Cardiac Arrest and Emergency Care

The incidence of both out-of-hospital and in-hospital cardiac arrest increased during the coronavirus disease 2019 (COVID-19) pandemic. Patient survival and neurologic outcome after both out-of-hospital and in-hospital cardiac arrest were reduced. Direct effects of the COVID-19 illness combined with indirect effects of the pandemic on patient's behavior and health care systems contributed to these changes. Understanding the potential factors offers the opportunity to improve future response and save lives.

Right ventricular injury in patients with COVID-19-related ARDS eligible for ECMO support: a multicenter retrospective study

BACKGROUND

Coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) is associated with high mortality. Extracorporeal membrane oxygenation (ECMO) has been proposed in this setting, but optimal criteria to select target patients remain unknown. Our hypothesis is that evaluation of right ventricular (RV) function could be helpful. The aims of our study were to report the incidence and outcomes of patients eligible for ECMO according to EOLIA criteria, and to identify a subgroup of patients with RV injury, which could be a target for ECMO.

METHODS

Retrospective observational study involving 3 French intensive care units (ICUs) of teaching hospitals. Patients with confirmed SARS-CoV-2 infection between March 2020 and March 2021, presenting ARDS and with available echocardiography, were included. Patients were classified in three groups according to whether or not they met the EOLIA criteria and the presence of RV injury (RVI) ("EOLIA -", "EOLIA + RVI -" and "EOLIA + RVI + "). RVI was defined by the association of RV to left ventricular end-diastolic area ratio > 0.8 and paradoxical septal motion. Kaplan-Meier survival curves were used to analyze outcome as well as a Cox model for 90 day mortality.

RESULTS

915 patients were hospitalized for COVID-19, 418 of them with ARDS. A total of 283 patients with available echocardiography were included. Eighteen (6.3%) patients received ECMO. After exclusion of these patients, 107 (40.5%) were classified as EOLIA -, 126 (47.5%) as EOLIA + RVI -, and 32 (12%) as EOLIA + RVI + . Ninety-day mortality was 21% in the EOLIA-group, 44% in the EOLIA + RVI-group, and 66% in the EOLIA + RVI + group (p < 0.001). After adjustment, RVI was statistically associated with 90-day mortality (HR = 1.92 [1.10-3.37]).

CONCLUSIONS

Among COVID-19-associated ARDS patients who met the EOLIA criteria, those with significant RV pressure overload had a particularly poor outcome. This subgroup may be a more specific target for ECMO. This represented 12% of our cohort compared to 60% of patients who met the EOLIA criteria only. How the identification of this high-risk subset of patients translates into patient-centered outcomes remains to be evaluated.

Differences of respiratory mechanics in mechanical ventilation of acute respiratory distress syndrome between patients with COVID-19 and Influenza A

BACKGROUND

Whether COVID-19-induced acute respiratory distress syndrome (ARDS) should be approached differently in terms of mechanical ventilation therapy compared to other virus-induced ARDS is debatable. Therefore, we aimed to ascertain whether the respiratory mechanical characteristics of COVID-19-induced ARDS differ from those of influenza A induced ARDS, in order to establish a rationale for mechanical ventilation therapy in COVID-19-induced ARDS.

METHODS

This was a retrospective cohort study comparing patients with COVID-19-induced ARDS and influenza A induced ARDS. We included intensive care unit (ICU) patients with COVID-19 or Influenza A aged ≥ 19, who were diagnosed with ARDS according to the Berlin definition between January 2015 and July 2021. Ventilation parameters for respiratory mechanics were collected at specific times on days one, three, and seven after intubation.

RESULTS

The median age of the 87 participants was 71.0 (62.0-78.0) years old, and 63.2% were male. The ratio of partial pressure of oxygen in arterial blood to the fractional of inspiratory oxygen concentration in COVID-19-induced ARDS was lower than that in influenza A induced ARDS during the initial stages of mechanical ventilation (influenza A induced ARDS 216.1 vs. COVID-19-induced ARDS 167.9, p = 0.009, day 1). The positive end expiratory pressure remained consistently higher in the COVID-19 group throughout the follow-up period (7.0 vs. 10.0, p < 0.001, day 1). COVID-19 and influenza A initially showed different directions for peak inspiratory pressure and dynamic compliance; however, after day 3, both groups exhibited similar directions. Dynamic driving pressure exhibited opposite trends between the two groups during mechanical ventilation.

CONCLUSIONS

Respiratory mechanics show clear differences between COVID-19-induced ARDS and influenza A induced ARDS. Based on these findings, we can consider future treatment strategies for COVID-19-induced ARDS.

Risk Factors for the Mortality of Patients With Coronavirus Disease 2019 Requiring Extracorporeal Membrane Oxygenation in a Non-Centralized Setting: A Nationwide Study

BACKGROUND

Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO.

METHODS

We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan-Meier (KM) method.

RESULTS

Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010-1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312-7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004).

CONCLUSION

Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.

Extracorporeal Life Support Organization Registry International Report 2022: 100,000 Survivors

The Extracorporeal Life Support Organization (ELSO) maintains the world's largest extracorporeal membrane oxygenation (ECMO) registry by volume, center participation, and international scope. This 2022 ELSO Registry Report describes the program characteristics of ECMO centers, processes of ECMO care, and reported outcomes. Neonates (0-28 days), children (29 days-17 years), and adults (≥18 years) supported with ECMO from 2009 through 2022 and reported to the ELSO Registry were included. This report describes adjunctive therapies, support modes, treatments, complications, and survival outcomes. Data are presented descriptively as counts and percent or median and interquartile range (IQR) by year, group, or level. Missing values were excluded before calculating descriptive statistics. Complications are reported per 1,000 ECMO hours. From 2009 to 2022, 154,568 ECMO runs were entered into the ELSO Registry. Seven hundred and eighty centers submitted data during this time (557 in 2022). Since 2009, the median annual number of adult ECMO runs per center per year increased from 4 to 15, whereas for pediatric and neonatal runs, the rate decreased from 12 to 7. Over 50% of patients were transferred to the reporting ECMO center; 20% of these patients were transported with ECMO. The use of prone positioning before respiratory ECMO increased from 15% (2019) to 44% (2021) for adults during the coronavirus disease-2019 (COVID-19) pandemic. Survival to hospital discharge was greatest at 68.5% for neonatal respiratory support and lowest at 29.5% for ECPR delivered to adults. By 2022, the Registry had enrolled its 200,000th ECMO patient and 100,000th patient discharged alive. Since its inception, the ELSO Registry has helped centers measure and compare outcomes across its member centers and strategies of care. Continued growth and development of the Registry will aim to bolster its utility to patients and centers.

Relationship between the Pre-ECMO and ECMO Time and Survival of Severe COVID-19 Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) is the etiology of acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) is used to support gas exchange in patients who have failed conventional mechanical ventilation. However, there is no clear consensus on the timing of ECMO use in severe COVID-19 patients.

OBJECTIVE

The aim of this study is to compare the differences in pre-ECMO time and ECMO duration between COVID-19 survivors and non-survivors and to explore the association between them.

METHODS

PubMed, the Cochrane Library, Embase, and other sources were searched until 21 October 2022. Studies reporting the relationship between ECMO-related time and COVID-19 survival were included. All available data were pooled using random-effects methods. Linear regression analysis was used to determine the correlation between pre-ECMO time and ECMO duration. The meta-analysis was registered with PROSPERO under registration number CRD42023403236.

RESULTS

Out of the initial 2473 citations, we analyzed 318 full-text articles, and 54 studies were included, involving 13,691 patients. There were significant differences between survivors and non-survivors in the time from COVID-19 diagnosis (standardized mean difference (SMD) = -0.41, 95% confidence interval (CI): [-0.53, -0.29], p < 0.00001), hospital (SMD = -0.53, 95% CI: [-0.97, -0.09], p = 0.02) and intensive care unit (ICU) admission (SMD = -0.28, 95% CI: [-0.49, -0.08], p = 0.007), intubation or mechanical ventilation to ECMO (SMD = -0.21, 95% CI: [-0.32, -0.09], p = 0.0003) and ECMO duration (SMD = -0.18, 95% CI: [-0.30, -0.06], p = 0.003). There was no statistical association between a longer time from symptom onset to ECMO (hazard ratio (HR) = 1.05, 95% CI: [0.99, 1.12], p = 0.11) or time from intubation or mechanical ventilation (MV) and the risk of mortality (highest vs. lowest time groups odds ratio (OR) = 1.18, 95% CI: [0.78, 1.78], p = 0.42; per one-day increase OR = 1.14, 95% CI: [0.86, 1.52], p = 0.36; HR = 0.99, 95% CI: [0.95, 1.02], p = 0.39). There was no linear relationship between pre-ECMO time and ECMO duration.

CONCLUSION

There are differences in pre-ECMO time between COVID-19 survivors and non-survivors, and there is insufficient evidence to conclude that longer pre-ECMO time is responsible for reduced survival in COVID-19 patients. ECMO duration differed between survivors and non-survivors, and the timing of pre-ECMO does not have an impact on ECMO duration. Further studies are needed to explore the association between pre-ECMO and ECMO time in the survival of COVID-19 patients.

Potential for recovery after extremely prolonged VV-ECMO support in well-selected severe COVID-19 patients: a retrospective cohort study

BACKGROUND

VenoVenous ExtraCorporeal Membrane Oxygenation (VV-ECMO) has been widely used as supportive therapy for severe respiratory failure related to Acute Respiratory Distress Syndrome (ARDS) due to coronavirus 2019 (COVID-19). Only a few data describe the maximum time under VV-ECMO during which pulmonary recovery remains possible. The main objective of this study is to describe the outcomes of prolonged VV-ECMO in patients with COVID-19-related ARDS.

METHODS

This retrospective study was conducted at a tertiary ECMO center in Brussels, Belgium, between March 2020 and April 2022. All adult patients with ARDS due to COVID-19 who were managed with ECMO therapy for more than 50 days as a bridge to recovery were included.

RESULTS

Fourteen patients met the inclusion criteria. The mean duration of VV-ECMO was 87 ± 29 days. Ten (71%) patients were discharged alive from the hospital. The 90-day survival was 86%, and the one-year survival was 71%. The evolution of the patients was characterized by very impaired pulmonary compliance that started to improve slowly and progressively on day 53 (± 25) after the start of ECMO. Of note, four patients improved substantially after a second course of steroids.

CONCLUSIONS

There is potential for recovery in patients with very severe ARDS due to COVID-19 supported by VV-ECMO for up to 151 days.

Usefulness of the Yokohama Advanced Cardiopulmonary Help Team in patients with acute respiratory distress syndrome

Aim

To evaluate whether establishing an extracorporeal membrane oxygenation (ECMO) specialist team, termed the Yokohama Advanced Cardiopulmonary Help Team (YACHT), affected the outcomes and centralization of patients requiring ECMO in Yokohama-Yokosuka regions.

Methods

This retrospective observational study included patients aged ≥18 years and treated with venovenous-ECMO for severe acute respiratory distress syndrome (ARDS) from 2014 to 2023. The primary outcome was intensive care unit (ICU) mortality. The secondary outcomes included ICU-, mechanical ventilator-, and ECMO-free days and complications during the first 28 days.

Results

This study included 46 (12 without- and 34 with-YACHT) patients. Among with-YACHT patients, 24 were transferred to our hospital from other hospitals, 14 were assessed by dispatched ECMO physicians, and 9 were transferred after ECMO introduction. No without-YACHT patients were transferred from other hospitals. With-YACHT patients experienced coronavirus disease 2019-associated respiratory failure more frequently (0 vs. 27, p < 0.001) and had higher Acute Physiology and Chronic Health Evaluation II scores (19 vs. 24, p = 0.037) and lower Respiratory Extracorporeal Membrane Oxygenation Survival Prediction scores (4 vs. 2, p = 0.021). ICU mortality was not significantly different between the groups (2 vs. 4, p = 0.67). ICU- (14 vs. 9, p = 0.10), ventilator- (11 vs. 5, p = 0.01), and ECMO-free days (20 vs. 14, p = 0.038) were higher before YACHT establishment. The incidences of complications were not significantly different between the groups.

Conclusions

Mortality was not significantly different pre- and post-YACHT establishment; however, it helped promote regionalization and centralization in Yokohama-Yokosuka areas. We will collect more cases to demonstrate YACHT's usefulness.

Extracorporeal membrane oxygenation for COVID-19-associated severe acute respiratory distress syndrome in Canada: Analysis of data from the Canadian Nosocomial Infection Surveillance Program

Background

Extracorporeal membrane oxygenation (ECMO) for COVID-19 across Canada has not been well-described. We studied trends for patients with COVID-19-related acute respiratory distress syndrome who received ECMO.

Methods

Multicentre retrospective cohort study using data from the Canadian Nosocomial Infection Surveillance Program across four different waves. Surveillance data was collected between March 2020 and June 2022. We reported data stratified by ECMO status and wave.

Results

ECMO recipients comprised 299 (6.8%) of the 4,408 critically ill patients included. ECMO recipients were younger (median age 49 versus 62 years, p < 0.001), less likely to be vaccinated against COVID-19 (Wave 4 data: 5.3% versus 19%; p = 0.002), and had fewer comorbidities compared to patients who did not receive ECMO. Thirty-day all-cause mortality was similar between the ECMO and non-ECMO groups (23% versus 26%; p = 0.25). Among ECMO recipients, mortality tended to decrease across Waves 1 to 4: 48%, 31%, 18%, and 16%, respectively (p = 0.04 for trend). However, this was no longer statistically significant when removing the high mortality during Wave 1 (p = 0.15).

Conclusions

Our findings suggest that critically ill patients in Canadian hospitals who received ECMO had different characteristics from those who did not receive ECMO. We also observed a trend of decreased mortality over the waves for the ECMO group. Possible explanatory factors may include potential delay in ECMO initiation during Wave 1, evolution of the virus, better understanding of COVID-19 disease and ECMO use, and new medical treatments and vaccines available in later waves. These findings may provide insight for future potential pandemics.

Supervised machine learning model to predict mortality in patients undergoing venovenous extracorporeal membrane oxygenation from a nationwide multicentre registry

BACKGROUND

Existing models have performed poorly when predicting mortality for patients undergoing venovenous extracorporeal membrane oxygenation (VV-ECMO). This study aimed to develop and validate a machine learning (ML)-based prediction model to predict 90-day mortality in patients undergoing VV-ECMO.

METHODS

This study included 368 patients with acute respiratory failure undergoing VV-ECMO from 16 tertiary hospitals across South Korea between 2012 and 2015. The primary outcome was the 90-day mortality after ECMO initiation. The inputs included all available features (n=51) and those from the electronic health record (EHR) systems without preprocessing (n=40). The discriminatory strengths of ML models were evaluated in both internal and external validation sets. The models were compared with conventional models, such as respiratory ECMO survival prediction (RESP) and predicting death for severe acute respiratory distress syndrome on VV-ECMO (PRESERVE).

RESULTS

Extreme gradient boosting (XGB) (areas under the receiver operating characteristic curve, AUROC 0.82, 95% CI (0.73 to 0.89)) and light gradient boosting (AUROC 0.81 (95% CI 0.71 to 0.88)) models achieved the highest performance using EHR's and all other available features. The developed models had higher AUROCs (95% CI 0.76 to 0.82) than those of RESP (AUROC 0.66 (95% CI 0.56 to 0.76)) and PRESERVE (AUROC 0.71 (95% CI 0.61 to 0.81)). Additionally, we achieved an AUROC (0.75) for 90-day mortality in external validation in the case of the XGB model, which was higher than that of RESP (0.70) and PRESERVE (0.67) in the same validation dataset.

CONCLUSIONS

ML prediction models outperformed previous mortality risk models. This model may be used to identify patients who are unlikely to benefit from VV-ECMO therapy during patient selection.

Outcomes of patients with COVID-19 supported by venovenous extracorporeal membrane oxygenation for greater than 90 days

Objective

To determine the characteristics and outcomes of patients requiring prolonged (>90 days) venovenous extracorporeal membrane oxygenation (VV ECMO) support for refractory Coronavirus disease 2019 (COVID-19)-associated respiratory failure.

Methods

A retrospective, observational analysis of consecutive patients requiring VV ECMO for COVID-19-associated respiratory failure was performed at a single institution between March 2020 and January 2022. Data were collected from the medical records. Patients were predominantly cannulated and supported long-term with a single, dual-lumen cannula in the internal jugular vein with the tip positioned in the pulmonary artery. All patients were managed with an awake VV ECMO approach, emphasizing avoidance of sedatives, extubation, ambulation, physical therapy, and nutrition. Patients requiring >90 days of ECMO were identified, analyzed, and compared to those needing a shorter duration of support.

Results

A total of 44 patients were supported on VV ECMO during the study period, of whom 36 (82%) survived to discharge. Thirty-one patients were supported for <90 days, of whom 28 (90%) were discharged alive. Thirteen patients required >90 days of ECMO. All patients were extubated. Eight patients (62%) survived to discharge, with 1 patient requiring lung transplantation prior to decannulation. All survivors were free from mechanical ventilation and alive at a 6-month follow-up. Of the 4 patients who died on prolonged ECMO, 2 developed hemothorax necessitating surgery and 2 succumbed to fatal intracranial hemorrhage.

Conclusions

Patients treated with VV ECMO for COVID-19-associated respiratory failure may require prolonged support to recover. Extubation, ambulation, aggressive rehabilitation, and nutritional support while on ECMO can yield favorable outcomes.

Acute respiratory distress syndrome heterogeneity and the septic ARDS subgroup

Acute respiratory distress syndrome (ARDS) is an acute diffuse inflammatory lung injury characterized by the damage of alveolar epithelial cells and pulmonary capillary endothelial cells. It is mainly manifested by non-cardiogenic pulmonary edema, resulting from intrapulmonary and extrapulmonary risk factors. ARDS is often accompanied by immune system disturbance, both locally in the lungs and systemically. As a common heterogeneous disease in critical care medicine, researchers are often faced with the failure of clinical trials. Latent class analysis had been used to compensate for poor outcomes and found that targeted treatment after subgrouping contribute to ARDS therapy. The subphenotype of ARDS caused by sepsis has garnered attention due to its refractory nature and detrimental consequences. Sepsis stands as the most predominant extrapulmonary cause of ARDS, accounting for approximately 32% of ARDS cases. Studies indicate that sepsis-induced ARDS tends to be more severe than ARDS caused by other factors, leading to poorer prognosis and higher mortality rate. This comprehensive review delves into the immunological mechanisms of sepsis-ARDS, the heterogeneity of ARDS and existing research on targeted treatments, aiming to providing mechanism understanding and exploring ideas for accurate treatment of ARDS or sepsis-ARDS.

Ischemic stroke and intracranial hemorrhage in extracorporeal membrane oxygenation for COVID-19: A systematic review and meta-analysis

PURPOSE

Extracorporeal membrane oxygenation (ECMO) is employed to support critically ill COVD-19 patients. The occurrence of ischemic stroke and intracranial hemorrhage (ICH), as well as the implementation of anticoagulation strategies under the dual influence of ECMO and COVID-19 remain unclear. We conducted a systematic review and meta-analysis to describe the ischemic stroke, ICH and overall in-hospital mortality in COVID-19 patients receiving ECMO and summarize the anticoagulation regimens.

METHODS

EMBASE, PubMed, Cochrane, and Scopus were searched for studies examining ischemic stroke, ICH, and mortality in COVID-19 patients supported with ECMO. The outcomes were incidences of ischemic stroke, ICH, overall in-hospital mortality and anticoagulation regimens. We calculated the pooled proportions and 95% confidence intervals (CIs) to summarize the results.

RESULTS

We analyzed 12 peer-reviewed studies involving 6039 COVID-19 patients. The incidence of ischemic stroke had a pooled estimate of 2.2% (95% CI: 1.2%-3.2%). The pooled prevalence of ICH was 8.0% (95% CI: 6.3%-9.6%). The pooled estimate of overall in-hospital mortality was 40.3% (95% CI: 33.1%-47.5%). The occurrence of ICH was significantly higher in COVID-19 patients supported with ECMO than in other respiratory ECMO [relative risk=1.75 (95% CI: 1.00-3.07)]. Unfractionated heparin was the most commonly used anticoagulant, and anticoagulation monitoring practice varied among centers.

CONCLUSIONS

Ischemic stroke and ICH were common under the double "hit" of COVID-19 and ECMO. The prevalence of ICH was significantly higher in COVID-19 patients supported with ECMO than non-COVID-19 patients requiring ECMO. Individualized anticoagulation regimens may be a good choice to balance thrombosis and bleeding. More detailed research and further exploration are needed to clarify the underlying mechanism and clinical management decisions.

Venovenous extracorporeal membrane oxygenation for COVID-19 and influenza H1N1 associated acute respiratory distress syndrome: A comparative cohort study in China

Background

Venovenous extracorporeal membrane oxygenation (VV-ECMO) has been demonstrated to be effective in treating patients with virus-induced acute respiratory distress syndrome (ARDS). However, whether the management of ECMO is different in treating H1N1 influenza and coronavirus disease 2019 (COVID-19)-associated ARDS patients remains unknown.

Methods

This is a retrospective cohort study. We included 12 VV-ECMO-supported COVID-19 patients admitted to The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Eighth People's Hospital, and Wuhan Union Hospital West Campus between January 23 and March 31, 2020. We retrospectively included VV-ECMO-supported patients with COVID-19 and H1N1 influenza-associated ARDS. Clinical characteristics, respiratory mechanics including plateau pressure, driving pressure, mechanical power, ventilatory ratio (VR) and lung compliance, and outcomes were compared.

Results

Data from 25 patients with COVID-19 (n=12) and H1N1 (n=13) associated ARDS who had received ECMO support were analyzed. COVID-19 patients were older than H1N1 influenza patients (P=0.004). The partial pressure of arterial carbon dioxide (PaCO2) and VR before ECMO initiation were significantly higher in COVID-19 patients than in H1N1 influenza patients (P <0.001 and P=0.004, respectively). COVID-19 patients showed increased plateau and driving pressure compared with H1N1 subjects (P=0.013 and P=0.018, respectively). Patients with COVID-19 remained longer on ECMO support than did H1N1 influenza patients (P=0.015). COVID-19 patients who required ECMO support also had fewer intensive care unit and ventilator-free days than H1N1.

Conclusions

Compared with H1N1 influenza patients, COVID-19 patients were older and presented with increased PaCO2 and VR values before ECMO initiation. The differences between ARDS patients with COVID-19 and influenza on VV-ECMO detailed herein could be helpful for obtaining a better understanding of COVID-19 and for better clinical management.

The implementation of target trial emulation for causal inference: a scoping review

OBJECTIVES

We aim to investigate the implementation of Target Trial Emulation (TTE) for causal inference, involving research topics, frequently used strategies, and issues indicating the need for future improvements.

STUDY DESIGN AND SETTING

We performed a scoping review by following the Joanna Briggs Institute (JBI) guidance and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. A health research-focused librarian searched multiple medical databases, and two independent reviewers completed screening and extraction within covidence review management software.

RESULTS

Our search resulted in 1,240 papers, of which 96 papers were eligible for data extraction. Results show a significant increase in the use of TTE in 2018 and 2021. The study topics varied and focused primarily on cancer, cardiovascular and cerebrovascular diseases, and infectious diseases. However, not all papers specified well all three critical components for generating robust causal evidence: time-zero, random assignment simulation, and comparison strategy. Some common issues were observed from retrieved papers, and key limitations include residual confounding, limited generalizability, and a lack of reporting guidance that need to be improved.

CONCLUSION

Uneven adherence to the TTE framework exists, and future improvements are needed to progress applications using causal inference with observational data.

Functional Status and Quality of Life 6 Months After Extracorporeal Membrane Oxygenation Therapy for COVID-19-Related Pulmonary Failure

Extracorporeal membrane oxygenation (ECMO) is increasingly used in COVID-19-related pulmonary failure and the number of patients recovering from COVID-19 is growing. Here, we assess survival and recovery 6 months after ECMO for COVID-19. From April 2020 to September 2021, n = 60 (60.5 [51.0-65.0] years, 23.3% female) were treated with venovenous/venoarterial ECMO for COVID-19. 41.7% were weaned off ECMO, survival-to-discharge was 40.0% (n = 24). Age (63.0 [60.0-66.8] vs. 55.0 [43.8-60.0] years, p < 0.001), vasoactive support (97.2% vs . 75.0%, p = 0.013), and pre-ECMO SOFA scores (13.0 [12.0-14.8] vs. 12.0 [10.0-13.8] p = 0.036) correlated with nonsurvival. All patients aged >65 years, with histories of neoplasia, immunocompromise, chronic renal failure, or frailty died. After 6 months, 20 were alive (6-month survival 33.3%, survival conditioned on survival-to-discharge 83.3%), with follow-up in 19. 57.9% showed no relevant, 26.3% moderate, 15.8% severe deficits. Cardiopulmonary status was satisfactory (mMRC level: 84.2% ≤2). 73.7% were independent in daily life. Cognitive impairments were frequent (52.6%). 26.3% showed moderate depression, 15.8% posttraumatic stress disorder. Social and work life were considerably affected. Extracorporeal membrane oxygenation thus can serve as salvage therapy in COVID-19, but advanced age, immunocompromise, histories of neoplasia, and frailty must be considered as relative contraindications. Age, vasoactive support, and SOFA scores assist discriminating in daily practice. Deficits after 6 months are substantial, and efforts need to focus on long-term recovery.

Intracranial hemorrhage in patients treated for SARS-CoV-2 with extracorporeal membrane oxygenation: A systematic review and meta-analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is routinely used in patients with severe respiratory failure and has been increasingly needed during the COVID-19 pandemic. In patients treated with ECMO, significant intracranial hemorrhage (ICH) risk exists due to circuit characteristics, anticoagulation, and disease characteristics. ICH risk may be substantially higher in COVID-19 patients than patients treated with ECMO for other indications.

METHODS

We systematically reviewed current literature regarding ICH during ECMO treatment of COVID-19. We utilized Embase, MEDLINE, and Cochrane Library databases. Meta-analysis was performed for included comparative studies. Quality assessment was performed using MINORS criteria.

RESULTS

A total of 54 studies with 4000 ECMO patients were included, all retrospective. Risk of bias was increased via MINORS score primarily due to retrospective designs. ICH was more likely in COVID-19 patients (RR 1.72, 95% CI 1.23, 2.42). Mortality among COVID patients on ECMO with ICH was 64.0%, compared with 41% in patients without ICH (RR1.9, 95% 1.44, 2.51).

CONCLUSION

This study suggests increased hemorrhage rates in COVID-19 patients on ECMO compared to similar controls. Hemorrhage reduction strategies may include atypical anticoagulants, conservative anticoagulation strategies, or biotechnology advances in circuit design and surface coatings.

Demographics and Outcomes of Extracorporeal Membrane Oxygenation in COVID-19 Patients: National Database Analysis

INTRODUCTION

The effectiveness of extracorporeal membrane oxygenation (ECMO) in treating COVID-19 patients has been variable. To gain a better insight, we examined the outcomes of ECMO in COVID-19 patients using data from the 2020 National Inpatient Sample database.

METHODS

We analyzed data from adult hospital admissions where COVID-19 was the primary diagnosis. The primary outcome was all-cause inpatient mortality. Secondary outcomes were length of stay (LOS), cost, and discharge disposition.

RESULTS

We identified 1,048,025 COVID-19 admissions, of which 98,528 were on mechanical ventilation (MV), and only 1.8% received ECMO. In-hospital mortality of mechanically ventilated patients who received ECMO was 49%, compared to 59% with no ECMO (p < 0.001). ECMO treatment was associated with a reduced risk of mortality (HR = 0.67, p < 0.0001, CI 0.57-0.79) even after adjustment for confounders and other comorbidities. Patients on ECMO had significantly extended hospital stays and were more likely to be discharged to an acute care facility. Younger and male patients were more likely to receive ECMO treatment. Females had a lower mortality risk, while race and obesity were not associated with an increased risk of death.

CONCLUSION

ECMO treatment may offer survival benefits in severe COVID-19. Based on our findings, we suggest early ECMO treatment for patients with a high mortality risk.

Veno-arterial extracorporeal membrane oxygenation for circulatory failure in COVID-19 patients: insights from the ECMOSARS registry

OBJECTIVES

The clinical profile and outcomes of patients with Coronavirus Disease 2019 (COVID-19) who require veno-arterial extracorporeal membrane oxygenation (VA-ECMO) or veno-arterial-venous extracorporeal membrane oxygenation (VAV-ECMO) are poorly understood. We aimed to describe the characteristics and outcomes of these patients and to identify predictors of both favourable and unfavourable outcomes.

METHODS

ECMOSARS is a multicentre, prospective, nationwide French registry enrolling patients who require veno-venous extracorporeal membrane oxygenation (ECMO)/VA-ECMO in the context of COVID-19 infection (652 patients at 41 centres). We focused on 47 patients supported with VA- or VAV-ECMO for refractory cardiogenic shock.

RESULTS

The median age was 49. Fourteen percent of patients had a prior diagnosis of heart failure. The most common aetiologies of cardiogenic shock were acute pulmonary embolism (30%), myocarditis (28%) and acute coronary syndrome (4%). Extracorporeal cardiopulmonary resuscitation (E-CPR) occurred in 38%. In-hospital survival was 28% in the whole cohort, and 43% when E-CPR patients were excluded. ECMO cannulation was associated with significant improvements in pH and FiO2 on day 1, but non-survivors showed significantly more severe acidosis and higher FiO2 than survivors at this point (P = 0.030 and P = 0.006). Other factors associated with death were greater age (P = 0.02), higher body mass index (P = 0.03), E-CPR (P = 0.001), non-myocarditis aetiology (P = 0.02), higher serum lactates (P = 0.004), epinephrine (but not noradrenaline) use before initiation of ECMO (P = 0.003), haemorrhagic complications (P = 0.001), greater transfusion requirements (P = 0.001) and more severe Survival after Veno-Arterial ECMO (SAVE) and Sonographic Assessment of Intravascular Fluid Estimate (SAFE) scores (P = 0.01 and P = 0.03).

CONCLUSIONS

We report the largest focused analysis of VA- and VAV-ECMO recipients in COVID-19. Although relatively rare, the need for temporary mechanical circulatory support in these patients is associated with poor prognosis. However, VA-ECMO remains a viable solution to rescue carefully selected patients. We identified factors associated with poor prognosis and suggest that E-CPR is not a reasonable indication for VA-ECMO in this population.

Reporting of Observational Studies Explicitly Aiming to Emulate Randomized Trials: A Systematic Review

Importance

Observational (nonexperimental) studies that aim to emulate a randomized trial (ie, the target trial) are increasingly informing medical and policy decision-making, but it is unclear how these studies are reported in the literature. Consistent reporting is essential for quality appraisal, evidence synthesis, and translation of evidence to policy and practice.

Objective

To assess the reporting of observational studies that explicitly aimed to emulate a target trial.

Evidence Review

We searched Medline, Embase, PsycINFO, and Web of Science for observational studies published between March 2012 and October 2022 that explicitly aimed to emulate a target trial of a health or medical intervention. Two reviewers double-screened and -extracted data on study characteristics, key predefined components of the target trial protocol and its emulation (eligibility criteria, treatment strategies, treatment assignment, outcome[s], follow-up, causal contrast[s], and analysis plan), and other items related to the target trial emulation.

Findings

A total of 200 studies that explicitly aimed to emulate a target trial were included. These studies included 26 subfields of medicine, and 168 (84%) were published from January 2020 to October 2022. The aim to emulate a target trial was explicit in 70 study titles (35%). Forty-three studies (22%) reported use of a published reporting guideline (eg, Strengthening the Reporting of Observational Studies in Epidemiology). Eighty-five studies (43%) did not describe all key items of how the target trial was emulated and 113 (57%) did not describe the protocol of the target trial and its emulation.

Conclusion and Relevance

In this systematic review of 200 studies that explicitly aimed to emulate a target trial, reporting of how the target trial was emulated was inconsistent. A reporting guideline for studies explicitly aiming to emulate a target trial may improve the reporting of the target trial protocols and other aspects of these emulation attempts.

Angong niuhuang wan attenuates LPS-induced acute lung injury by inhibiting PIK3CG/p65/MMP9 signaling in mice based on proteomics

Acute lung injury (ALI) is a serious pulmonary complication that often arises from pneumonia, respiratory tract infections caused by bacteria or viruses, and other factors. It is characterized by acute onset and high mortality. Angong Niuhuang Wan (AGNHW) is a renowned emergency medicine in traditional Chinese medicine, known as the "cool open (febrile disease) three treasures" and regarded as the first of the "three treasures". Previously studies have confirmed that AGNHW has anti-inflammatory effects, improves cerebral circulation, reduces brain edema, and protects vascular endothelium. However, the active components and pharmacological mechanisms of AGNHW in treating ALI remain unclear. In this study, we confirmed that AGNHW can inhibit cytokine storm activity and reduce inflammation induced by LPS in ALI mice. We then analyzed differential proteins using proteomic technology and identified 741 differential proteins. By combining network pharmacological analysis, we deeply discussed the key active components and mechanism of AGNHW in treating ALI. By constructing the interaction network between disease and drug, we identified 21 key active components (such as Quercetin, Kaempferol, and Crocetin) and 25 potential core targets (such as PIK3CG, p65, and MMP9). These candidate targets play an important role in anti-inflammation and immune regulation. Through enrichment analysis of core targets, we found several pathways related to ALI, such as the NF-κB signaling pathway, TNF signaling pathway, and Toll-like receptor signaling pathway. This indicates that AGNHW plays a therapeutic role in ALI through multi-components, multi-targets, and multi-pathways.

Retrospective analysis of factors associated with outcome in veno-venous extra-corporeal membrane oxygenation

BACKGROUND

The outcome of Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) in acute respiratory failure may be influenced by patient-related factors, center expertise and modalities of mechanical ventilation (MV) during ECMO. We determined, in a medium-size ECMO center in Switzerland, possible factors associated with mortality during VV-ECMO for acute respiratory failure of various etiologies.

METHODS

We retrospectively analyzed all patients treated with VV-ECMO in our University Hospital from 2012 to 2019 (pre-COVID era). Demographic variables, severity scores, MV duration before ECMO, pre and on-ECMO arterial blood gases and respiratory variables were collected. The primary outcome was ICU mortality. Data were compared between survivors and non-survivors, and factors associated with mortality were assessed in univariate and multivariate analyses.

RESULTS

Fifty-one patients (33 ARDS, 18 non-ARDS) were included. ICU survival was 49% (ARDS, 39%; non-ARDS 67%). In univariate analyses, a higher driving pressure (DP) at 24h and 48h on ECMO (whole population), longer MV duration before ECMO and higher DP at 24h on ECMO (ARDS patients), were associated with mortality. In multivariate analyses, ECMO indication, higher DP at 24h on ECMO and, in ARDS, longer MV duration before ECMO, were independently associated with mortality.

CONCLUSIONS

DP on ECMO and longer MV duration before ECMO (in ARDS) are major, and potentially modifiable, factors influencing outcome during VV-ECMO.

Implementation of the trial emulation approach in medical research: a scoping review

BACKGROUND

When conducting randomised controlled trials is impractical, an alternative is to carry out an observational study. However, making valid causal inferences from observational data is challenging because of the risk of several statistical biases. In 2016 Hernán and Robins put forward the 'target trial framework' as a guide to best design and analyse observational studies whilst preventing the most common biases. This framework consists of (1) clearly defining a causal question about an intervention, (2) specifying the protocol of the hypothetical trial, and (3) explaining how the observational data will be used to emulate it.

METHODS

The aim of this scoping review was to identify and review all explicit attempts of trial emulation studies across all medical fields. Embase, Medline and Web of Science were searched for trial emulation studies published in English from database inception to February 25, 2021. The following information was extracted from studies that were deemed eligible for review: the subject area, the type of observational data that they leveraged, and the statistical methods they used to address the following biases: (A) confounding bias, (B) immortal time bias, and (C) selection bias.

RESULTS

The search resulted in 617 studies, 38 of which we deemed eligible for review. Of those 38 studies, most focused on cardiology, infectious diseases or oncology and the majority used electronic health records/electronic medical records data and cohort studies data. Different statistical methods were used to address confounding at baseline and selection bias, predominantly conditioning on the confounders (N = 18/49, 37%) and inverse probability of censoring weighting (N = 7/20, 35%) respectively. Different approaches were used to address immortal time bias, assigning individuals to treatment strategies at start of follow-up based on their data available at that specific time (N = 21, 55%), using the sequential trial emulations approach (N = 11, 29%) or the cloning approach (N = 6, 16%).

CONCLUSION

Different methods can be leveraged to address (A) confounding bias, (B) immortal time bias, and (C) selection bias. When working with observational data, and if possible, the 'target trial' framework should be used as it provides a structured conceptual approach to observational research.

Long-Term Outcomes of Extracorporeal Life Support in Respiratory Failure

Although extracorporeal life support is an expensive method with serious risks of complications, it is nowadays a well-established and generally accepted method of organ support. In patients with severe respiratory failure, when conventional mechanical ventilation cannot ensure adequate blood gas exchange, veno-venous extracorporeal membrane oxygenation (ECMO) is the method of choice. An improvement in oxygenation or normalization of acid-base balance by itself does not necessarily mean an improvement in the outcome but allows us to prevent potential negative effects of mechanical ventilation, which can be considered a crucial part of complex care leading potentially to an improvement in the outcome. The disconnection from ECMO or discharge from the intensive care unit should not be viewed as the main goal, and the long-term outcome of the ECMO-surviving patients should also be considered. Approximately three-quarters of patients survive the veno-venous ECMO, but various (both physical and psychological) health problems may persist. Despite these, a large proportion of these patients are eventually able to return to everyday life with relatively little limitation of respiratory function. In this review, we summarize the available knowledge on long-term mortality and quality of life of ECMO patients with respiratory failure.

Veno-venous extracorporeal membrane oxygenation in patients with SARS-CoV-2 pneumonia in Brazil: a case series

OBJECTIVE

The world has been suffering from the COVID-19 pandemic. Some COVID-19 patients develop severe viral pneumonia, requiring mechanical ventilation and measures to treat refractory hypoxemia, such as a protective ventilation strategy, prone positioning, and the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO). We describe a case series of 30 COVID-19 patients who needed VV-ECMO at the Hospital Alemão Oswaldo Cruz, located in the city of São Paulo, Brazil.

METHODS

We included all patients who required VV-ECMO due to COVID-19 pneumonia between March of 2020 and June of 2021.

RESULTS

Prior to VV-ECMO, patients presented with the following median scores: SOFA score, 11; APPS score, 7; Respiratory ECMO Survival Prediction score, 2; and Murray score, 3.3. The 60-day-in-hospital mortality was 33.3% (n = 10).

CONCLUSIONS

Although our patients had a highly severe profile, our results were similar to those of other cohort studies in the literature. This demonstrates that VV-ECMO can be a good tool even in a pandemic situation when it is managed in an experienced center.

Extracorporeal Membrane Oxygenation for Acute Respiratory Failure Due to COVID-19: A Multicenter Matched Cohort Study

Mechanical ventilation for respiratory failure due to COVID-19 is associated with significant morbidity and mortality. Veno-venous extracorporeal membrane oxygenation (ECMO) is an attractive management option. This study sought to determine the effect of ECMO on hospital mortality and discharge condition in this population. We conducted a retrospective multicenter study to emulate a pragmatic targeted trial comparing ECMO to mechanical ventilation without ECMO for severe COVID-19. Data were gathered from a large hospital network database in the US. Adults admitted with COVID-19 were included if they were managed with ECMO or mechanical ventilation for severe hypoxemia and excluded if they had significant comorbidities or lacked functional independence on admission. The groups underwent coarsened exact matching on multiple clinical variables. The primary outcome was adjusted in-hospital mortality; secondary outcomes included ventilator days, intensive care days, and discharge destination. A total of 278 ECMO patients were matched to 2,054 comparison patients. Adjusted in-hospital mortality was significantly less in the ECMO group (38.8% vs. 60.1%, p < 0.001). Extracorporeal membrane oxygenation was associated with higher rates of liberation from mechanical ventilation, intensive care discharge, and favorable discharge destination. These findings support the use of ECMO for well-selected patients with severe acute respiratory failure due to COVID-19.

Lactate Dehydrogenase and Hemorrhagic Stroke During Extracorporeal Membrane Oxygenation for COVID-19

PURPOSE

Hemorrhagic stroke (HS) is a devastating complication during extracorporeal membrane oxygenation (ECMO) but markers of risk stratification during COVID-19 are unknown. Lactate dehydrogenase (LDH) is a readily available biomarker of cell injury and permeability. We sought to determine whether an elevated LDH before ECMO placement is related to the occurrence of HS during ECMO for COVID-19.

METHODS

Adult patients with COVID-19 requiring ECMO between March 2020 and February 2022 were included. LDH values prior to ECMO placement were captured. Patients were categorized into high (> 750 U/L) or low (≤ 750 U/L) LDH groups. Multivariable regression modeling was used to determine the association between LDH and HS during ECMO.

RESULTS

There were 520 patients that underwent ECMO placement in 17 centers and 384 had an available LDH. Of whom, 122 (32%) had a high LDH. The overall incidence of HS was 10.9%, and patients with high LDH had a higher incidence of HS than those with low LDH level (17% vs 8%, p = 0.007). At 100 days, the probability of a HS was 40% in the high LDH group and 23% in those with a low LDH, p = 0.002. After adjustment for clinical covariates, high LDH remained associated with subsequent HS (aHR: 2.64, 95% CI 1.39-4.92). Findings were similar when restricting to patients supported by venovenous ECMO only.

CONCLUSION

Elevated LDH prior to ECMO cannulation is associated with a higher incidence of HS during device support. LDH can risk stratify cases for impending cerebral bleeding during ECMO.

Advances in the use of ECMO in oncology patient

BACKGROUND

Over the past decade, ECMO has provided temporary cardiopulmonary support to an increasing number of patients, but the use of extracorporeal membrane oxygenation (ECMO) to provide temporary respiratory and circulatory support to adult patients with malignancy remains controversial.

OBJECTIVES

This paper reviews the specific use of extracorporeal membrane oxygenation (ECMO) in oncology patients.

METHODS

We searched PubMed, CINAHL, Cochrane Library, and Embase databases for studies on the use of ECMO in cancer patients between 1998 and 2022. Twenty-four retrospective, prospective, and case reports were included. The primary outcome was survival during extracorporeal membrane oxygenation.

RESULTS

Most studies suggest that ECMO can be used in oncology patients requiring life support during surgery, solid tumor patients with respiratory failure, and hematological tumor patients requiring ECOM as a supportive means of chemotherapy; however, in patients with hematologic oncology undergoing hematopoietic stem cell transplantation, there was no clear benefit after the use of ECMO.

CONCLUSION

Current research suggests that ECMO may be considered as a salvage support in specific cancer patients. Future studies should include larger sample sizes than those already conducted, including studies on efficacy, adverse events, and health.

ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies

The aim of these guidelines is to update the 2017 clinical practice guideline (CPG) of the European Society of Intensive Care Medicine (ESICM). The scope of this CPG is limited to adult patients and to non-pharmacological respiratory support strategies across different aspects of acute respiratory distress syndrome (ARDS), including ARDS due to coronavirus disease 2019 (COVID-19). These guidelines were formulated by an international panel of clinical experts, one methodologist and patients' representatives on behalf of the ESICM. The review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and grade recommendations and the quality of reporting of each study based on the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network guidelines. The CPG addressed 21 questions and formulates 21 recommendations on the following domains: (1) definition; (2) phenotyping, and respiratory support strategies including (3) high-flow nasal cannula oxygen (HFNO); (4) non-invasive ventilation (NIV); (5) tidal volume setting; (6) positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM); (7) prone positioning; (8) neuromuscular blockade, and (9) extracorporeal life support (ECLS). In addition, the CPG includes expert opinion on clinical practice and identifies the areas of future research.

Venovenous extracorporeal membrane oxygenation in COVID-19-related acute respiratory distress syndrome : What's the catch?

COVID-19 is still around, and in the most severe cases can rapidly progress to acute respiratory distress syndrome. When mechanical ventilation fails to improve oxygenation, we desperately shift our management to venovenous extracorporeal membrane oxygenation (vv-ECMO). In this opinion article, we discuss which patients are the most suitable to select for this technique, reiterate previous observations in acute respiratory distress syndrome, and the options for the patients judged not fitting for ECMO.

Extracorporeal membrane oxygenation for COVID-19 and influenza associated acute respiratory distress syndrome: a systematic review

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used extensively for H1N1 influenza and coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) to improve gas exchange and quickly correct hypoxemia and hypercapnia. This systematic review summarized the evidence on ECMO for the treatment of COVID-19 and influenza-associated ARDS.

RESEARCH DESIGN AND METHODS

This is a systematic review and meta-analysis of studies to compare the efficacy and safety of ECMO with conventional mechanical ventilation in adults with COVID-19 and influenza-associated ARDS. The study performed a structured search on PubMed, Embase, Web of Science, Scopus and The Cochrane Library. The primary outcome was hospital mortality.

RESULTS

The study included 15 observational studies with 5239 patients with COVID-19 and influenza-associated ARDS. The use of ECMO significantly reduced in-hospital mortality in COVID-19-associated ARDS (OR = 0.40; 95% CI = 0.27-0.58; P < 0.00001) but did not reduce influenza-related mortality (OR = 1.08; 95% CI = 0.41-2.87; P = 0.87). Moreover, ECMO treatment meaningfully increased the incidence of bleeding complications (OR = 7.66; 95% CI = 2.47-23.72; P = 0.0004).

CONCLUSION

The use of ECMO significantly reduced in-hospital mortality in COVID-19- associated ARDS, which may be related to the advances in ECMO-related techniques and the increased experience of clinicians. However, the incidence of bleeding complications remains high. [Figure: see text].

Prognostic value of respiratory compliance course on mortality in COVID-19 patients with vv-ECMO

BACKGROUND

COVID-19-associated acute respiratory distress syndrome (ARDS) supported by veno-venous extra-corporal membrane oxygenation (vv-ECMO) results in a high in-hospital mortality rate of more than 35%. However, after cannulation, no prognostic factor has been described to guide the management of these patients. The objective was to assess the association between static respiratory compliance over the first 10 days post-vv-ECMO implantation on 180-day mortality.

RESULTS

In this multicentric retrospective study in three ECMO referral centers, all patients with COVID-19-associated ARDS supported by vv-ECMO were included from 03/01/2020 to 12/31/2021. Patients were ventilated with ultra-protective settings targeting a driving pressure lower than 15 cmH₂O. 122 patients were included. Median age was 59 IQR (52-64), 83 (68%) were male, with a median body mass index of 33 (28-37) kg/m². Delay between first symptoms to vv-ECMO implantation was 16 (10-21) days. Six-month death was 48%. Over the first ten days, compliance increased in 180 day survivors [from 18 (12-25) to 20 (15-27) mL/cmH₂O] compared to non-survivors [from 12 (9-20) to 10 (8-14) mL/cmH₂O, p interaction < 0.0001]. A time varying multivariable Cox model found age, history of chronic lung disease, compliance from day one to day ten and sweep gas flow from day one to day ten as independent factors associated with 180-day mortality.

CONCLUSIONS

In COVID-19-associated ARDS, static respiratory compliance course over the first ten days post-vv-ECMO implantation is associated with 180-day mortality. This new information may provide crucial information on the patient's prognosis for intensivists.

Reduced anticoagulation strategy is associated with a lower incidence of intracerebral hemorrhage in COVID-19 patients on extracorporeal membrane oxygenation

BACKGROUND

Optimal anticoagulation strategies for COVID-19 patients with the acute respiratory distress syndrome (ARDS) on venovenous extracorporeal membrane oxygenation (VV ECMO) remain uncertain. A higher incidence of intracerebral hemorrhage (ICH) during VV ECMO support compared to non-COVID-19 viral ARDS patients has been reported, with increased bleeding rates in COVID-19 attributed to both intensified anticoagulation and a disease-specific endotheliopathy. We hypothesized that lower intensity of anticoagulation during VV ECMO would be associated with a lower risk of ICH. In a retrospective, multicenter study from three academic tertiary intensive care units, we included patients with confirmed COVID-19 ARDS requiring VV ECMO support from March 2020 to January 2022. Patients were grouped by anticoagulation exposure into higher intensity, targeting anti-factor Xa activity (anti-Xa) of 0.3-0.4 U/mL, versus lower intensity, targeting anti-Xa 0.15-0.3 U/mL, cohorts. Mean daily doses of unfractionated heparin (UFH) per kg bodyweight and effectively measured daily anti-factor Xa activities were compared between the groups over the first 7 days on ECMO support. The primary outcome was the rate of ICH during VV ECMO support.

RESULTS

141 critically ill COVID-19 patients were included in the study. Patients with lower anticoagulation targets had consistently lower anti-Xa activity values over the first 7 ECMO days (p < 0.001). ICH incidence was lower in patients in the lower anti-Xa group: 4 (8%) vs 32 (34%) events. Accounting for death as a competing event, the adjusted subhazard ratio for the occurrence of ICH was 0.295 (97.5% CI 0.1-0.9, p = 0.044) for the lower anti-Xa compared to the higher anti-Xa group. 90-day ICU survival was higher in patients in the lower anti-Xa group, and ICH was the strongest risk factor associated with mortality (odds ratio [OR] 6.8 [CI 2.1-22.1], p = 0.001).

CONCLUSIONS

For COVID-19 patients on VV ECMO support anticoagulated with heparin, a lower anticoagulation target was associated with a significant reduction in ICH incidence and increased survival.

Obesity associated with improved mortality of extracorporeal membrane oxygenation for severe COVID-19 pneumonia

INTRODUCTION

Determining a patient's candidacy for extracorporeal membrane oxygenation (ECMO) in severe COVID-19 pneumonia is a critical aspect of efficient healthcare delivery. A body mass index (BMI) ≥40 is considered a relative contraindication for ECMO by the Extracorporeal Life Support Organization (ELSO). We sought to determine the impact of obesity on the survival of patients with COVID-19 on ECMO.

METHODS

This project was a retrospective review of a multicenter US database from January 2020 to December 2021. The primary outcome was in-hospital mortality after ECMO initiation, with a comparison between patients classified into body mass index categories (<30, 30-39.9, and ≥40). Secondary outcomes included ventilator days, intensive care days, and complications.

RESULTS

We completed records review on 359 patients, with 90 patients excluded because of missing data. The overall mortality for the 269 patients was 37.5%. Patients with a BMI <30 had higher odds of mortality compared to all patients with BMI >30 (OR 1.98; p = 0.013), those with BMI 30-39.9 (OR 1.84; p = 0.036), and BMI ≥40 (OR 2.33; p = 0.024). There were no differences between BMI groups for ECMO duration; length of stay (LOS); or rate of bloodstream infection, stroke, or blood transfusion. Age, ECMO duration, and modified-Elixhauser index were not independent risk factors for mortality.

CONCLUSIONS

In patients receiving ECMO for severe COVID-19, neither obesity (BMI >30) nor morbid obesity (BMI >40) were associated with in-hospital mortality. These results are consistent with previous reports and held true after adjusting for age and comorbidities. Our data suggest further examination of the recommendations to withhold ECMO in patients who are obese.

An Intensivist-Led Extracorporeal Membrane Oxygenation Program: Design, Implementation, and Outcomes of the First Five Years

We describe the development, implementation, and outcomes of an intensivist-led adult extracorporeal life support (ECLS) program using intensivists both to perform venovenous (V-V), venoarterial (V-A), and extracorporeal cardiopulmonary resuscitation (ECPR) cannulations, and to manage patients on ECLS throughout their ICU course. All adults supported with ECLS at the University of New Mexico Hospital (UNMH) from February 1, 2017 to December 31, 2021 were retrospectively analyzed. A total of 203 ECLS cannulations were performed in 198 patients, including 116 V-A cannulations (including 65 during ECPR) and 87 V-V cannulations (including 38 in patients with COVID-19). UNMH intensivists performed 195 cannulations, with 9 cannulation complications. Cardiothoracic surgeons performed 8 cannulations. Overall survival to hospital discharge or transfer was 46.5%. Survival was 32.3% in the ECPR group and 56% in the non-ECPR V-A group. In the V-V cohort, survival was 66.7% in the COVID-19-negative patients and 34.2% in the COVID-19-positive patients. This large series of intensivist-performed ECLS cannulations-including V-A, V-V, and ECPR modalities-demonstrates the successful implementation of a comprehensive intensivist-led ECLS program. With outcomes comparable to those in the literature, our program serves as a model for the initiation and development of ECLS programs in settings with limited access to local subspecialty cardiothoracic surgical services.

Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome Due to Severe Fever With Thrombocytopenia Syndrome

Few cases of acute respiratory distress syndrome (ARDS) in severe fever with thrombocytopenia syndrome (SFTS) have been treated with venovenous extracorporeal membrane oxygenation (VV-ECMO), and its role remains unclear. A 73-year-old Japanese woman presented with multiple organ failure (MOF) due to SFTS, including liver, neural, hematologic, renal, and ARDS. VV-ECMO for refractory hypoxemia under lung-protective ventilation with prone positioning led to gradual respiratory improvement, and she was successfully weaned on the 19th day of hospitalization. However, she died from persistent MOF on the 60th day of hospitalization. VV-ECMO contributed to recovery from ARDS but not from the ultimate cause of death, i.e., MOF. SFTS could have variable MOFs with different disease trajectories, which influence the decision for VV-ECMO.

Acute Congestive Hepatopathy, Diagnosed With Point-of-Care Hepatic Ultrasound in a Patient on Extracorporeal Membrane Oxygenation

•Ultrasound is a valuable tool for interrogating cannula position in ECMO patients. •RV dysfunction is common in patients with COVID-19 ARDS. •Consider insidious RV dysfunction when changing central ECMO flow rates. •Direct hepatic venous spectral Doppler evaluation may help to optimize ECMO settings. •Ultrasound may be helpful in diagnosing congestive hepatopathy in central ECMO.

Extracorporeal Membrane Oxygenation Then and Now; Broadening Indications and Availability

Extracorporeal membrane oxygenation (ECMO) is a life support technology provided to children to support respiratory failure, cardiac failure, or cardiopulmonary resuscitation after failure of conventional management. Over the decades, ECMO has expanded in use, advanced in technology, shifted from experimental to a standard of care, and evidence supporting its use has increased. The expanded ECMO indications and medical complexity of children have also necessitated focused studies in the ethical domain such as decisional authority, resource allocation, and equitable access.

Impact of Coronavirus Disease 2019 Pandemic on Cardiac Arrest and Emergency Care

The incidence of both out-of-hospital and in-hospital cardiac arrest increased during the coronavirus disease 2019 (COVID-19) pandemic. Patient survival and neurologic outcome after both out-of-hospital and in-hospital cardiac arrest were reduced. Direct effects of the COVID-19 illness combined with indirect effects of the pandemic on patient's behavior and health care systems contributed to these changes. Understanding the potential factors offers the opportunity to improve future response and save lives.

A contemporary analysis of the volume-outcome relationship for extracorporeal membrane oxygenation in the United States

BACKGROUND

A paradoxical increase in mortality following extracorporeal membrane oxygenation at high-volume centers has previously been demonstrated. We examined the association between annual hospital volume and outcomes within a contemporary, national cohort of extracorporeal membrane oxygenation patients.

METHODS

All adults requiring extracorporeal membrane oxygenation for postcardiotomy syndrome, cardiogenic shock, respiratory failure, or mixed cardiopulmonary failure were identified in the 2016 to 2019 Nationwide Readmissions Database. Patients undergoing heart and/or lung transplantation were excluded. A multivariable logistic regression with hospital extracorporeal membrane oxygenation volume parametrized as restricted cubic splines was developed to characterize the risk-adjusted association between volume and mortality. The volume corresponding to the maximum of the spline (43 cases/year) was used to categorize centers as low- or high-volume.

RESULTS

An estimated 26,377 patients met the study criteria, and 48.7% were managed at high-volume hospitals. Patients at low- and high-volume hospitals had similar age, sex, and rates of elective admission. Notably, patients at high-volume hospitals less frequently required extracorporeal membrane oxygenation for postcardiotomy syndrome but more commonly for respiratory failure. After risk adjustment, high-volume hospital status was associated with reduced odds of in-hospital mortality, relative to low-volume hospitals (adjusted odds ratio 0.81, 95% confidence interval 0.78-0.97). Interestingly, patients at high-volume hospitals faced a 5.2-day increment in length of stay (95% confidence interval 3.8-6.5) and $23,500 in attributable costs (95% confidence interval 8,300-38,700).

CONCLUSION

The present study found that greater extracorporeal membrane oxygenation volume was associated with decreased mortality but higher resource use. Our findings may help inform policies regarding access to and centralization of extracorporeal membrane oxygenation care in the United States.

The effect of therapeutic plasma exchange therapy on veno-venous ECMO weaning success in severe COVID-19 ARDS patients

INTRODUCTION

Primarily, this study aimed to investigate the effect of TPE (therapeutic plasma exchange) treatment on successful ECMO weaning in severe COVID-19 ARDS patients treated with V-V ECMO.

METHODS

The study was applied retrospectively on patients over the age of 18 who were hospitalized in the ICU between January 1, 2020 and March 1, 2022.

RESULTS

The study was performed on 33 patients, 36.3% (n: 12) of whom received TPE treatment. The rate of successful ECMO weaning was statistically higher in the TPE treatment group (without TPE: 14.3% [n: 3], with TPE: 50% [n: 6], p = 0.044). The 1-month mortality was also statistically lower in the TPE treatment group (p = 0.044). In the logistic analysis, It was found that the risk of unsuccessful ECMO weaning increased 6 times in those who did not receive TPE treatment (OR; 6.0, 95% CI; 1.134-31.735, p = 0.035).

CONCLUSION

TPE treatment may increase the success rate of V-V ECMO weaning in severe COVID-19 ARDS patients treated with V-V ECMO.

Prognostic factors associated with mortality among patients receiving venovenous extracorporeal membrane oxygenation for COVID-19: a systematic review and meta-analysis

BACKGROUND

Venovenous extracorporeal membrane oxygenation (ECMO) can be considered for patients with COVID-19-associated acute respiratory distress syndrome (ARDS) who continue to deteriorate despite evidence-based therapies and lung-protective ventilation. The Extracorporeal Life Support Organization has emphasised the importance of patient selection; however, to better inform these decisions, a comprehensive and evidence-based understanding of the risk factors associated with poor outcomes is necessary. We aimed to summarise the association between pre-cannulation prognostic factors and risk of mortality in adult patients requiring venovenous ECMO for the treatment of COVID-19.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE and Embase from Dec 1, 2019, to April 14, 2022, for randomised controlled trials and observational studies involving adult patients who required ECMO for COVID-19-associated ARDS and for whom pre-cannulation prognostic factors associated with in-hospital mortality were evaluated. We conducted separate meta-analyses of unadjusted and adjusted odds ratios (uORs), adjusted hazard ratios (aHRs), and mean differences, and excluded studies if these data could not be extracted. We assessed the risk of bias using the Quality in Prognosis Studies tool and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. Our protocol was registered with the Open Science Framework registry, osf.io/6gcy2.

FINDINGS

Our search identified 2888 studies, of which 42 observational cohort studies involving 17 449 patients were included. Factors that had moderate or high certainty of association with increased mortality included patient factors, such as older age (adjusted hazard ratio [aHR] 2·27 [95% CI 1·63-3·16]), male sex (unadjusted odds ratio [uOR] 1·34 [1·20-1·49]), and chronic lung disease (aHR 1·55 [1·20-2·00]); pre-cannulation disease factors, such as longer duration of symptoms (mean difference 1·51 days [95% CI 0·36-2·65]), longer duration of invasive mechanical ventilation (uOR 1·94 [1·40-2·67]), higher partial pressure of arterial carbon dioxide (mean difference 4·04 mm Hg [1·64-6·44]), and higher driving pressure (aHR 2·36 [1·40-3·97]); and centre factors, such as less previous experience with ECMO (aOR 2·27 [1·28-4·05].

INTERPRETATION

The prognostic factors identified highlight the importance of patient selection, the effect of injurious lung ventilation, and the potential opportunity for greater centralisation and collaboration in the use of ECMO for the treatment of COVID-19-associated ARDS. These factors should be carefully considered as part of a risk stratification framework when evaluating a patient for potential treatment with venovenous ECMO.

FUNDING

None.

Extracorporeal membrane oxygenation for COVID-19-related acute respiratory distress syndrome: a narrative review

A growing body of evidence supports the use of extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) refractory to maximal medical therapy. ARDS may develop in a proportion of patients hospitalized for coronavirus disease 2019 (COVID-19) and ECMO may be used to manage patients refractory to maximal medical therapy to mitigate the risk of ventilator-induced lung injury and provide lung rest while awaiting recovery. The mortality of COVID-19-related ARDS was variously reassessed during the pandemic. Veno-venous (VV) ECMO was the default choice to manage refractory respiratory failure; however, with concomitant severe right ventricular dysfunction, venoarterial (VA) ECMO or mechanical right ventricular assist devices with extracorporeal gas exchange (Oxy-RVAD) were also considered. ECMO has also been used to manage special populations such as pregnant women, pediatric patients affected by severe forms of COVID-19, and, in cases with persistent and seemingly irreversible respiratory failure, as a bridge to successful lung transplantation. In this narrative review, we outline and summarize the most recent evidence that has emerged on ECMO use in different patient populations with COVID-19-related ARDS.

Levosimendan in patients undergoing extracorporeal membrane oxygenation after cardiac surgery: an emulated target trial using observational data

BACKGROUND

Retrospective cohorts have suggested that levosimendan may facilitate the weaning of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). We therefore studied this clinical question by emulating a randomized trial with observational data.

METHODS

All patients with refractory postcardiotomy cardiogenic shock and assisted with VA-ECMO, admitted to a surgical intensive care unit at La Pitié-Salpêtrière Hospital between 2016 and 2019, were eligible. To avoid immortal-time bias, we emulated a target trial sequentially comparing levosimendan administration versus no levosimendan administration in patients treated with VA-ECMO. The primary outcome was time to successful ECMO weaning. The secondary outcomes were 30-day and 1-year mortality. We performed a multivariable analysis to adjust for confounding at baseline.

RESULTS

Two hundred and thirty-nine patients were included in the study allowing building a nested trials cohort of 1434 copies of patients. No association of levosimendan treatment and VA-ECMO weaning was found (HR = 0.91, [0.57; 1.45], p = 0.659 in multivariable analysis), or 30-day mortality (OR = 1.03, [0.52; 2.03], p = 0.940) and 1-year mortality (OR = 1.00, [0.53; 1.89], p = 0.999).

CONCLUSIONS

Using the emulated target trial framework, this study did not find any association of levosimendan treatment and ECMO weaning success after postcardiotomy cardiogenic shock. However, the population of interest remains heterogeneous and subgroups might benefit from levosimendan.

Extracorporeal Membrane Oxygenation for COVID-19: Comparison of Outcomes to Non-COVID-19-Related Viral Acute Respiratory Distress Syndrome From the Extracorporeal Life Support Organization Registry

To compare complications and mortality between patients that required extracorporeal membrane oxygenation (ECMO) support for acute respiratory distress syndrome (ARDS) due to COVID-19 and non-COVID-19 viral pathogens.

DESIGN

Retrospective observational cohort study.

SETTING

Adult patients in the Extracorporeal Life Support Organization registry.

PATIENTS

Nine-thousand two-hundred ninety-one patients that required ECMO for viral mediated ARDS between January 2017 and December 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes of interest were mortality during ECMO support and prior to hospital discharge. Time-to-event analysis and logistic regression were used to compare outcomes between the groups. Among 9,291 included patients, 1,155 required ECMO for non-COVID-19 viral ARDS and 8,136 required ECMO for ARDS due to COVID-19. Patients with COVID-19 had longer duration of ECMO (19.6 d [interquartile range (IQR), 10.1-34.0 d] vs 10.7 d [IQR, 6.3-19.7 d]; p < 0.001), higher mortality during ECMO support (44.4% vs 27.5%; p < 0.001), and higher in-hospital mortality (50.2% vs 34.5%; p < 0.001). Further, patients with COVID-19 were more likely to experience mechanical and clinical complications (membrane lung failure, pneumothorax, intracranial hemorrhage, and superimposed infection). After adjusting for pre-ECMO disease severity, patients with COVID-19 were more than two times as likely to die in the hospital compared with patients with non-COVID-19 viral ARDS.

CONCLUSIONS

Patients with COVID-19 that require ECMO have longer duration of ECMO, more complications, and higher in-hospital mortality compared with patients with non-COVID-19-related viral ARDS. Further study in patients with COVID-19 is critical to identify the patient phenotype most likely to benefit from ECMO and to better define the role of ECMO in the management of this disease process.

Comparative outcomes of extracorporeal membrane oxygenation for COVID-19 delivered in experienced European centres during successive SARS-CoV-2 variant outbreaks (ECMO-SURGES): an international, multicentre, retrospective cohort study

BACKGROUND

To inform future research and practice, we aimed to investigate the outcomes of patients who received extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) due to different variants of SARS-CoV-2.

METHODS

This retrospective study included consecutive adult patients with laboratory-confirmed SARS-CoV-2 infection who received ECMO for ARDS in 21 experienced ECMO centres in eight European countries (Austria, Belgium, England, France, Germany, Italy, Portugal, and Spain) between Jan 1, 2020, and Sept 30, 2021. We collected data on patient characteristics, clinical status, and management before and after the initiation of ECMO. Participants were grouped according to SARS-CoV-2 variant (wild type, alpha, delta, or other) and period of the pandemic (first [Jan 1-June 30] and second [July 1-Dec 31] semesters of 2020, and first [Jan 1-June 30] and second [July 1-Sept 30] semesters of 2021). Descriptive statistics and Kaplan-Meier survival curves were used to analyse evolving characteristics, management, and patient outcomes over the first 2 years of the pandemic, and independent risk factors of mortality were determined using multivariable Cox regression models. The primary outcome was mortality 90 days after the initiation of ECMO, with follow-up to Dec 30, 2021.

FINDINGS

ECMO was initiated in 1345 patients. Patient characteristics and management were similar for the groups of patients infected with different variants, except that those with the delta variant had a younger median age and less hypertension and diabetes. 90-day mortality was 42% (569 of 1345 patients died) overall, and 43% (297/686) in patients infected with wild-type SARS-CoV-2, 39% (152/391) in those with the alpha variant, 40% (78/195) in those with the delta variant, and 58% (42/73) in patients infected with other variants (mainly beta and gamma). Mortality was 10% higher (50%) in the second semester of 2020, when the wild-type variant was still prevailing, than in other semesters (40%). Independent predictors of mortality were age, immunocompromised status, a longer time from intensive care unit admission to intubation, need for renal replacement therapy, and higher Sequential Organ Failure Assessment haemodynamic component score, partial pressure of arterial carbon dioxide, and lactate concentration before ECMO. After adjusting for these variables, mortality was significantly higher with the delta variant than with the other variants, the wild-type strain being the reference.

INTERPRETATION

Although crude mortality did not differ between variants, adjusted risk of death was highest for patients treated with ECMO infected with the delta variant of SARS-CoV-2. The higher virulence and poorer outcomes associated with the delta strain might relate to higher viral load and increased inflammatory response syndrome in infected patients, reinforcing the need for a higher rate of vaccination in the population and updated selection criteria for ECMO, should a new and highly virulent strain of SARS-CoV-2 emerge in the future. Mortality was noticeably lower than in other large, multicentre series of patients who received ECMO for COVID-19, highlighting the need to concentrate resources at experienced centres.

FUNDING

None.

Extracorporeal Membrane Oxygenation Selection by Multidisciplinary Consensus: The ECMO Council

Coronavirus disease 2019 (COVID-19) has increased the demand for extracorporeal membrane oxygenation (ECMO) and introduced distinct challenges to patient selection for ECMO. Standardized processes for patient selection amidst resource limitations are lacking, and data on ECMO consults are underreported. We retrospectively reviewed consecutive adult ECMO consults for acute respiratory failure received at a single academic medical center from April 1, 2020, to February 28, 2021, and evaluated the implementation of a multidisciplinary selection committee (ECMO Council) and standardized framework for patient selection for ECMO. During the 334-day period, there were 202 total ECMO consults; 174 (86.1%) included a diagnosis of COVID-19. Among all consults, 157 (77.7%) were declined and 41 (20.3%) resulted in the initiation of ECMO. Frequent reasons for decline included the presence of multiple relative contraindications (n = 33), age greater than 60 years (n = 32), and resource limitations (n = 27). The ECMO Council deliberated on every case in which an absolute contraindication was not present (n = 96) via an electronic teleconference platform. Utilizing multidisciplinary consensus together with a standardized process for patient selection in ECMO is feasible during a pandemic and may be reliably exercised over time. Whether such an approach is feasible at other centers remains unknown.

Extracorporeal Membrane Oxygenation in Acute Respiratory Failure

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a form of mechanical life support that provides full respiratory bypass in patients with severe respiratory failure as a bridge to recovery or lung transplantation. The use of ECMO for respiratory failure and capable centers offering ECMO has expanded over the years, increasing its availability. As VV-ECMO provides an artificial mechanism for oxygenation and decarboxylation of native blood, it allows for an environment in which safer mechanical ventilatory care may be provided, allowing for treatment and resolution of underlying respiratory pathologies. Landmark clinical trials have provided a framework for better understanding patient selection criteria, resource utilization, and outcomes associated with ECMO when applied in settings of refractory respiratory failure. Maintaining close vigilance and management of complications during ECMO as well as identifying strategies post-ECMO (e.g., recovery, transplantation, etc.), are critical to successful ECMO support. In this review, we examine considerations for candidate selection for VV-ECMO, review the evidence of utilizing VV-ECMO in respiratory failure, and provide practical considerations for managing respiratory ECMO patients, including complication identification and management, as well as assessing for the ability to separate from ECMO support and the procedures for decannulation.

Association of obesity paradox with prognosis of veno-venous-extracorporeal membrane oxygenation in patients with coronavirus disease 2019

Aim

Although the obesity paradox is known for various diseases, including cancer and acute respiratory distress syndrome, little is known about veno-venous extracorporeal membrane oxygenation (VV-ECMO) in patients with coronavirus disease 2019 (COVID-19). In this study, we aimed to investigate the association between body mass index (BMI) and prognosis in critical patients with COVID-19 requiring VV-ECMO.

Methods

We conducted a retrospective observational single-center study at Yokohama City University Civic General Medical Center between March 2020 and October 2021. Participants were patients with COVID-19 who required VV-ECMO. They were classified into two groups: BMI ≤30 kg/m² and >30 kg/m².

Results

In total, 23 patients were included in the analysis, with a median BMI of 28.7 kg/m². Overall, 22 patients were successfully weaned from the ECMO. When comparing the two groups, there was a trend toward fewer days from onset to ECMO induction in the BMI >30 kg/m² group. Moreover, the two groups had a similar prognosis. There were no statistically significant differences in the number of days from onset to hospitalization or the duration of ECMO induction between the groups.

Conclusion

VV-ECMO induction for patients with COVID-19 may lead to earlier indications in patients with BMI >30 kg/m² than in those with BMI ≤30 kg/m².