Comparison of mortality prediction models in acute respiratory distress syndrome undergoing extracorporeal membrane oxygenation and development of a novel prediction score: the PREdiction of Survival on ECMO Therapy-Score (PRESET-Score)

Outcomes following additional drainage during veno-venous extracorporeal membrane oxygenation: A single-center retrospective study

Refractory hypoxemia during veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) may require an additional cannula (VV-V ECMO) to improve oxygenation. This intervention includes risk of recirculation and other various adverse events (AEs) such as injury to the lung, cannula malpositioning, bleeding, circuit or cannula thrombosis requiring intervention (i.e., clot), or cerebral injury. During the study period, 23 of 142 V-V ECMO patients were converted to VV-V utilizing two separate cannulas for bi-caval drainage with an additional upper extremity cannula placed for return. Of those, 21 had COVID-19. In the first 24 h after conversion, ECMO flow rates were higher (5.96 vs 5.24 L/min, p = .002) with no significant change in pump speed (3764 vs 3630 revolutions per minute [RPMs], p = .42). Arterial oxygenation (PaO2) increased (87 vs 64 mmHg, p < .0001) with comparable pre-oxygenator venous saturation (61 vs 53.3, p = .12). By day 5, flows were similar to pre-conversion values at lower pump speed but with improved PaO2. Unadjusted survival was similar in those converted to VV-V ECMO compared to V-V ECMO alone (70% [16/23] vs 66.4% [79/119], p = .77). In a mixed effect regression model, any incidence of AEs, demonstrated a negative impact on PaO2 in the first 48 h but not at day 5. VV-V ECMO improved oxygenation with increasing flows without a significant difference in AEs or pump speed. AEs transiently impacted oxygenation. VV-V ECMO is effective and feasible strategy for refractory hypoxemia on VV-ECMO allowing for higher flow rate and unchanged pump speed.

External Validation of the PREdiction of Survival on Extracorporeal Membrane Oxygenation Therapy (PRESET) Score: A Single Center Cohort Experience

Acute respiratory distress syndrome (ARDS) is a life-threatening condition affecting >10% of intensive care unit (ICU) patients worldwide with a mortality of up to 59% depending on severity. Extracorporeal membrane oxygenation (ECMO) is a potentially life-saving procedure in severe ARDS but is technically and financially challenging. In recent years, various scoring systems have been proposed to select patients most likely to benefit from ECMO, with the PREdiction of Survival on ECMO Therapy (PRESET) score being one of the most used. We collected data from 283 patients with ARDS of various etiology who underwent veno-venous (V-V) ECMO therapy at a German tertiary care ICU from January 2012 to December 2022. Median age in the cohort was 56 years, and 64.31% were males. The in-hospital mortality rate was 50.88% (n = 144). The median (25%; 75% quartile) severity scores were 38 (31; 49) for Simplified Acute Physiology Score (SAPS) II, 12 (10; 13) for Sequential Organ Failure Assessment (SOFA) and 7 (5; 8) for PRESET. Simplified Acute Physiology Score-II displayed the best prognostic value (area under the receiver operating characteristic [AUROC]: 0.665 [confidence interval (CI): 0.574-0.756; p = 0.046]). Prediction performance was weak in all analyzed scores despite good calibration. Simplified Acute Physiology Score-II had the best discrimination after adjustment of our original cohort. The use of scores explored in this study for patient selection for eligibility for V-V ECMO is not recommendable.

A Mortality Prediction Score for Patients With Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO): The PREDICT VV-ECMO Score

Mortality prediction for patients with the severe acute respiratory distress syndrome (ARDS) supported with veno-venous extracorporeal membrane oxygenation (VV-ECMO) is challenging. Clinical variables at baseline and on day 3 after initiation of ECMO support of all patients treated from October 2010 through April 2020 were analyzed. Multivariate logistic regression analysis was used to identify score variables. Internal and external (Monza, Italy) validation was used to evaluate the predictive value of the model. Overall, 272 patients could be included for data analysis and creation of the PREDICT VV-ECMO score. The score comprises five parameters (age, lung fibrosis, immunosuppression, cumulative fluid balance, and ECMO sweep gas flow on day 3). Higher score values are associated with a higher probability of hospital death. The score showed favorable results in derivation and external validation cohorts (area under the receiver operating curve, AUC derivation cohort 0.76 [95% confidence interval, CI, 0.71-0.82] and AUC validation cohort 0.74 [95% CI, 0.67-0.82]). Four risk classes were defined: I ≤ 30, II 31-60, III 61-90, and IV ≥ 91 with a predicted mortality of 28.2%, 56.2%, 84.8%, and 96.1%, respectively. The PREDICT VV-ECMO score suggests favorable performance in predicting hospital mortality under ongoing ECMO support providing a sound basis for further evaluation in larger cohorts.

Venovenous extracorporeal membrane oxygenation for respiratory failure refractory to high frequency percussive ventilation

BACKGROUND

High frequency percussive ventilation (HFPV) has demonstrated improvements in gas exchange, but not in clinical outcomes.

OBJECTIVES

We utilize HFPV in patients failing conventional ventilation (CV), with rescue venovenous extracorporeal membrane oxygenation (VV ECMO) reserved for failure of HFPV, and we describe our experience with such a strategy.

METHODS

All adult patients (age >18 years) placed on HFPV for failure of CV at a single institution over a 10-year period were included. Those maintained on HFPV were compared to those that failed HFPV and required VV ECMO. Survival was compared to expected survival after upfront VV ECMO as estimated by VV ECMO risk prediction models.

RESULTS

Sixty-four patients were placed on HFPV for failure of CV over a 10-year period. After HFPV initiation, the P/F ratio rose from 76mmHg to 153.3mmHg in the 69 % of patients successfully maintained on HFPV. The P/F ratio only rose from 60.3mmHg to 67mmHg in the other 31 % of patients, and they underwent rescue ECMO with the P/F ratio rising to 261.6mmHg. The P/F ratio continued to improve in HFPV patients, while it declined in ECMO patients, such that at 24 h, the P/F ratio was greater in HFPV patients. The strongest independent predictor of failure of HFPV requiring rescue VV ECMO was a lower pO2 (p = .055). Overall in-hospital survival (59.4 %) was similar to that expected with upfront ECMO (RESP score: 57 %).

CONCLUSIONS

HFPV demonstrated significant and sustained improvements in gas exchange and may obviate the need for ECMO and its associated complications.

A Deep Learning Framework for Predicting Patient Decannulation on Extracorporeal Membrane Oxygenation Devices: Development and Model Analysis Study

BACKGROUND

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a therapy for patients with refractory respiratory failure. The decision to decannulate someone from extracorporeal membrane oxygenation (ECMO) often involves weaning trials and clinical intuition. To date, there are limited prognostication metrics to guide clinical decision-making to determine which patients will be successfully weaned and decannulated.

OBJECTIVE

This study aims to assist clinicians with the decision to decannulate a patient from ECMO, using Continuous Evaluation of VV-ECMO Outcomes (CEVVO), a deep learning-based model for predicting success of decannulation in patients supported on VV-ECMO. The running metric may be applied daily to categorize patients into high-risk and low-risk groups. Using these data, providers may consider initiating a weaning trial based on their expertise and CEVVO.

METHODS

Data were collected from 118 patients supported with VV-ECMO at the Columbia University Irving Medical Center. Using a long short-term memory-based network, CEVVO is the first model capable of integrating discrete clinical information with continuous data collected from an ECMO device. A total of 12 sets of 5-fold cross validations were conducted to assess the performance, which was measured using the area under the receiver operating characteristic curve (AUROC) and average precision (AP). To translate the predicted values into a clinically useful metric, the model results were calibrated and stratified into risk groups, ranging from 0 (high risk) to 3 (low risk). To further investigate the performance edge of CEVVO, 2 synthetic data sets were generated using Gaussian process regression. The first data set preserved the long-term dependency of the patient data set, whereas the second did not.

RESULTS

CEVVO demonstrated consistently superior classification performance compared with contemporary models (P<.001 and P=.04 compared with the next highest AUROC and AP). Although the model's patient-by-patient predictive power may be too low to be integrated into a clinical setting (AUROC 95% CI 0.6822-0.7055; AP 95% CI 0.8515-0.8682), the patient risk classification system displayed greater potential. When measured at 72 hours, the high-risk group had a successful decannulation rate of 58% (7/12), whereas the low-risk group had a successful decannulation rate of 92% (11/12; P=.04). When measured at 96 hours, the high- and low-risk groups had a successful decannulation rate of 54% (6/11) and 100% (9/9), respectively (P=.01). We hypothesized that the improved performance of CEVVO was owing to its ability to efficiently capture transient temporal patterns. Indeed, CEVVO exhibited improved performance on synthetic data with inherent temporal dependencies (P<.001) compared with logistic regression and a dense neural network.

CONCLUSIONS

The ability to interpret and integrate large data sets is paramount for creating accurate models capable of assisting clinicians in risk stratifying patients supported on VV-ECMO. Our framework may guide future incorporation of CEVVO into more comprehensive intensive care monitoring systems.

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.

Using Signal Features of Functional Near-Infrared Spectroscopy for Acute Physiological Score Estimation in ECMO Patients

Extracorporeal membrane oxygenation (ECMO) is a vital emergency procedure providing respiratory and circulatory support to critically ill patients, especially those with compromised cardiopulmonary function. Its use has grown due to technological advances and clinical demand. Prolonged ECMO usage can lead to complications, necessitating the timely assessment of peripheral microcirculation for an accurate physiological evaluation. This study utilizes non-invasive near-infrared spectroscopy (NIRS) to monitor knee-level microcirculation in ECMO patients. After processing oxygenation data, machine learning distinguishes high and low disease severity in the veno-venous (VV-ECMO) and veno-arterial (VA-ECMO) groups, with two clinical parameters enhancing the model performance. Both ECMO modes show promise in the clinical severity diagnosis. The research further explores statistical correlations between the oxygenation data and disease severity in diverse physiological conditions, revealing moderate correlations with the acute physiologic and chronic health evaluation (APACHE II) scores in the VV-ECMO and VA-ECMO groups. NIRS holds the potential for assessing patient condition improvements.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Study synopsis

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

Decreased PRESET-Score corresponds with improved survival in COVID-19 veno-venous extracorporeal membrane oxygenation

INTRODUCTION

The PREdiction of Survival on ECMO Therapy Score (PRESET-Score) predicts mortality while on veno-venous extracorporeal membrane oxygenation (VV ECMO) for acute respiratory distress syndrome. The aim of our study was to assess the association between PRESET-Score and survival in a large COVID-19 VV ECMO cohort.

METHODS

This was a single-center retrospective study of COVID-19 VV ECMO patients from 15 March 2020, to 30 November 2021. Univariable and Multivariable analyses were performed to assess patient survival and score differences.

RESULTS

A total of 105 patients were included in our analysis with a mean PRESET-Score of 6.74. Overall survival was 65.71%. The mean PRESET-Score was significantly lower in the survivor group (6.03 vs 8.11, p < 0.001). Patients with a PRESET-Score less than or equal to six had improved survival compared to those with a PRESET-Score greater than or equal to 8 (97.7% vs. 32.5%, p < 0.001). In a multivariable logistic regression, a lower PRESET-Score was also predictive of survival (OR 2.84, 95% CI 1.75, 4.63, p < 0.001).

CONCLUSION

We demonstrate that lower PRESET scores are associated with improved survival. The utilization of this validated, quantifiable, and objective scoring system to help identify COVID-19 patients with the greatest potential to benefit from VV-ECMO appears feasible. The incorporation of the PRESET-Score into institutional ECMO candidacy guidelines can help insure and improve access of this limited healthcare resource to all critically ill patients.

Efficacy of outcome prediction of the respiratory ECMO survival prediction score and the predicting death for severe ARDS on VV-ECMO score for patients with acute respiratory distress syndrome on extracorporeal membrane oxygenation

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) therapy for respiratory failure is an increasingly popular modality of support. Patient selection is an important aspect of outcome success. This review assesses the efficacy of the popular prognostic tools Respiratory ECMO Survival Prediction Score (RESP) and Predicting Death for Severe ARDS on VV-ECMO score (PRESERVE) for ECMO patient selection.

METHODS

A literature search was performed. Six publications were found to match the specified selection criteria. These publications were assessed and compared using the area under the receiver operating characteristic (AUROC) curve statistical method to ascertain the discriminatory ability of the models to predict treatment outcome.

RESULTS

Six articles were included in this review from 306 screened, of which all were retrospective cohort studies. Data was generated over a period of 3-9 years from 13 referring hospitals. Studies consisted of 467 male and 221 female (30 unknown) participants in total with a high heterogeneity. The PRESERVE prognostic model was found to have a higher AUROC score than the RESP model, however both models were found to be sub-optimal in their discriminatory ability. A high chance of bias was seen across all included studies.

CONCLUSION

It was the findings of this review, indicated by analysis using the AUROC measures, that the prognostic model PRESERVE performed better than RESP for predicting post ECMO therapy outcomes, for patients presenting with Acute Respiratory Distress Syndrome within their respective validated time frames, i.e., RESP at Intensive care unit (ICU) discharge and PRESERVE at 6 months post ICU discharge. However, It was recognized that comparator groups were small thereby introducing bias into the study. Further prospective, randomized studies would be necessary to effectively assess the utility of these predictive survival scores.

[When mechanical ventilation fails-Venovenous extracorporeal membrane oxygenation]

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is predominantly being used as a rescue strategy in patients with acute lung failure, suffering from severe oxygenation and/or decarboxylation impairment. Cannulas introduced into the central veins lead blood through a membrane oxygenator in which it is oxygenated via sweep gas (pO2 up to 600 mm Hg) flow, eliminating CO2. According to the largest randomized studies carried out so far, the two most important indications for VV-ECMO are hypoxic respiratory failure (paO2 < 80 mm Hg for more than 6 h) and refractory hypercapnia (pH < 7.25 und pCO2 > 60 mm Hg with a breathing frequency of >30/min) despite optimal protective mechanical ventilation settings (ARDS, Δp < 14 mbar, plateau pressure < 30 mbar, tidal volume VT < 6 ml/kg idealized body weight). Relative contraindications are life-limiting comorbidities and terminal pulmonary diseases that cannot be treated by lung transplantation. Advanced patient age is not regarded as an absolute contraindication, though it highly impacts ARDS survival rates, especially for pneumonia associated with coronavirus disease 2019 (COVID-19). The most frequent complications of VV-ECMO include bleeding, thrombus formation and rare cases of cannula-associated infections. Its use in nonintubated patients (awake ECMO) is possible in specific cases and has proven valuable as a bridge to lung transplant approach. Some ECMO centers offer cannulation of a patient at primary care hospitals, facilitating subsequent transport to the center (ECMO transport). The COVID-19 pandemic not only caused the number of VV-ECMO runs to skyrocket but has also drawn public attention to this extracorporeal procedure. Strict quality control to improve vvECMO outcomes according to the German hospital reform is urgently needed, especially so since the technique has a high demand in resources and bears significant risks when performed by untrained personnel.

Cannulate, extubate, ambulate approach for extracorporeal membrane oxygenation for COVID-19

OBJECTIVE

We compared outcomes in patients with severe COVID-19 versus non-COVID-19-related acute respiratory distress syndrome (ARDS) managed using a dynamic, goal-driven approach to venovenous extracorporeal membrane oxygenation (ECMO).

METHODS

We performed a retrospective, single-center analysis of our institutional ECMO registry using data from 2017 to 2021. We used Kaplan-Meier plots, Cox proportional hazard models, and propensity score analyses to evaluate the association of COVID-19 status (COVID-19-related ARDS vs non-COVID-19 ARDS) and survival to decannulation, discharge, tracheostomy, and extubation. We also conducted subgroup analyses to compare outcomes with the use of extracorporeal cytoreductive techniques (CytoSorb [CytoSorbents Corp] and plasmapheresis).

RESULTS

The sample comprised 128 patients, 50 with COVID-19 and 78 with non-COVID-19 ARDS. Advancing age was associated with decreased probability of survival to decannulation (P = .04). Compared with the non-COVID-19 ARDS group, patients with COVID-19 had a greater probability of survival to extubation (P < .01) and comparable survival to discharge (P = .14).

CONCLUSIONS

Patients with COVID-19 managed with ECMO had comparable outcomes as patients with non-COVID ARDS. A strategy of early extubation and ambulation might be a safe and effective strategy to improve outcomes and survival, even for patients with severe COVID-19.

Urine output as one of the most important features in differentiating in-hospital death among patients receiving extracorporeal membrane oxygenation: a random forest approach

BACKGROUND

It is common to support cardiovascular function in critically ill patients with extracorporeal membrane oxygenation (ECMO). The purpose of this study was to identify patients receiving ECMO with a considerable risk of dying in hospital using machine learning algorithms.

METHODS

A total of 1342 adult patients on ECMO support were randomly assigned to the training and test groups. The discriminatory power (DP) for predicting in-hospital mortality was tested using both random forest (RF) and logistic regression (LR) algorithms.

RESULTS

Urine output on the first day of ECMO implantation was found to be one of the most predictive features that were related to in-hospital death in both RF and LR models. For those with oliguria, the hazard ratio for 1 year mortality was 1.445 (p < 0.001, 95% CI 1.265-1.650).

CONCLUSIONS

Oliguria within the first 24 h was deemed especially significant in differentiating in-hospital death and 1 year mortality.

Validation of extracorporeal membrane oxygenation mortality prediction and severity of illness scores in an international COVID-19 cohort

BACKGROUND

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is a lifesaving support modality for severe respiratory failure, but its resource-intensive nature led to significant controversy surrounding its use during the COVID-19 pandemic. We report the performance of several ECMO mortality prediction and severity of illness scores at discriminating survival in a large COVID-19 V-V ECMO cohort.

METHODS

We validated ECMOnet, PRESET (PREdiction of Survival on ECMO Therapy-Score), Roch, SOFA (Sequential Organ Failure Assessment), APACHE II (acute physiology and chronic health evaluation), 4C (Coronavirus Clinical Characterisation Consortium), and CURB-65 (Confusion, Urea nitrogen, Respiratory Rate, Blood Pressure, age >65 years) scores on the ISARIC (International Severe Acute Respiratory and emerging Infection Consortium) database. We report discrimination via Area Under the Receiver Operative Curve (AUROC) and Area under the Precision Recall Curve (AURPC) and calibration via Brier score.

RESULTS

We included 1147 patients and scores were calculated on patients with sufficient variables. ECMO mortality scores had AUROC (0.58-0.62), AUPRC (0.62-0.74), and Brier score (0.286-0.303). Roch score had the highest accuracy (AUROC 0.62), precision (AUPRC 0.74) yet worst calibration (Brier score of 0.3) despite being calculated on the fewest patients (144). Severity of illness scores had AUROC (0.52-0.57), AURPC (0.59-0.64), and Brier Score (0.265-0.471). APACHE II had the highest accuracy (AUROC 0.58), precision (AUPRC 0.64), and best calibration (Brier score 0.26).

CONCLUSION

Within a large international multicenter COVID-19 cohort, the evaluated ECMO mortality prediction and severity of illness scores demonstrated inconsistent discrimination and calibration highlighting the need for better clinically applicable decision support tools.

Predictors associated with mortality of veno-venous extracorporeal membrane oxygenation therapy

BACKGROUND

The use of veno-venous extracorporeal membrane oxygenation (V-V ECMO) has rapidly increased in recent years. Today, applications of V-V ECMO include a variety of clinical conditions such as acute respiratory distress syndrome (ARDS), bridge to lung transplantation and primary graft dysfunction after lung transplantation. The purpose of the present study was to investigate in-hospital mortality of adult patients undergoing V-V ECMO therapy and to determine independent predictors associated with mortality.

METHODS

This retrospective study was conducted at the University Hospital Zurich, a designated ECMO center in Switzerland. Data was analyzed of all adult V-V ECMO cases from 2007 to 2019.

RESULTS

In total, 221 patients required V-V ECMO support (median age 50 years, 38.9% female). In-hospital mortality was 37.6% and did not statistically vary significantly between indications (P=0.61): 25.0% (1/4) for primary graft dysfunction after lung transplantation, 29.4% (5/17) for bridge to lung transplantation, 36.2% (50/138) for ARDS and 43.5% (27/62) for other pulmonary disease indications. Cubic spline interpolation showed no effect of time on mortality over the study period of 13 years. Multiple logistic regression modelling identified significant predictor variables associated with mortality: age [odds ratio (OR), 1.05; 95% confidence interval (CI): 1.02-1.07; P=0.001], newly detected liver failure (OR, 4.83; 95% CI: 1.27-20.3; P=0.02), red blood cell transfusion (OR, 1.91; 95% CI: 1.39-2.74; P<0.001) and platelet concentrate transfusion (OR, 1.93; 95% CI: 1.28-3.15; P=0.004).

CONCLUSIONS

In-hospital mortality of patients receiving V-V ECMO therapy remains relatively high. Patients' outcomes have not improved significantly in the observed period. We identified age, newly detected liver failure, red blood cell transfusion and platelet concentrate transfusion as independent predictors associated with in-hospital mortality. Incorporating such mortality predictors into decision making with regards to V-V ECMO use may increase its effectiveness and safety and may translate into better outcomes.

Mortality rates of severe COVID-19-related respiratory failure with and without extracorporeal membrane oxygenation in the Middle Ruhr Region of Germany

The use of extracorporeal membrane oxygenation (ECMO) is discussed to improve patients' outcome in severe COVID-19 with respiratory failure, but data on ECMO remains controversial. The aim of the study was to determine the characteristics of patients under invasive mechanical ventilation (IMV) with or without veno-venous ECMO support and to evaluate outcome parameters. Ventilated patients with COVID-19 with and without additional ECMO support were analyzed in a retrospective multicenter study regarding clinical characteristics, respiratory and laboratory parameters in day-to-day follow-up. Recruitment of patients was conducted during the first three COVID-19 waves at four German university hospitals of the Ruhr University Bochum, located in the Middle Ruhr Region. From March 1, 2020 to August 31, 2021, the charts of 149 patients who were ventilated for COVID-19 infection, were included (63.8% male, median age 67 years). Fifty patients (33.6%) received additional ECMO support. On average, ECMO therapy was initiated 15.6 ± 9.4 days after symptom onset, 10.6 ± 7.1 days after hospital admission, and 4.8 ± 6.4 days after the start of IMV. Male sex and higher SOFA and RESP scores were observed significantly more often in the high-volume ECMO center. Pre-medication with antidepressants was more often detected in survivors (22.0% vs. 6.5%; p = 0.006). ECMO patients were 14 years younger and presented a lower rate of concomitant cardiovascular diseases (18.0% vs. 47.5%; p = 0.0004). Additionally, cytokine-adsorption (46.0% vs. 13.1%; p < 0.0001) and renal replacement therapy (76.0% vs. 43.4%; p = 0.0001) were carried out more frequently; in ECMO patients thrombocytes were transfused 12-fold more often related to more than fourfold higher bleeding complications. Undulating C-reactive protein (CRP) and massive increase in bilirubin levels (at terminal stage) could be observed in deceased ECMO patients. In-hospital mortality was high (Overall: 72.5%, ECMO: 80.0%, ns). Regardless of ECMO therapy half of the study population deceased within 30 days after hospital admission. Despite being younger and with less comorbidities ECMO therapy did not improve survival in severely ill COVID-19 patients. Undulating CRP levels, a massive increase of bilirubin level and a high use of cytokine-adsorption were associated with worse outcomes. In conclusion, ECMO support might be helpful in selected severe cases of COVID-19.

Multi-horizon predictive models for guiding extracorporeal resource allocation in critically ill COVID-19 patients

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) resource allocation tools are currently lacking. We developed machine learning (ML) models for predicting COVID-19 patients at risk of receiving ECMO to guide patient triage and resource allocation.

MATERIAL AND METHODS

We included COVID-19 patients admitted to intensive care units for >24 h from March 2020 to October 2021, divided into training and testing development and testing-only holdout cohorts. We developed ECMO deployment timely prediction model ForecastECMO using Gradient Boosting Tree (GBT), with pre-ECMO prediction horizons from 0 to 48 h, compared to PaO2/FiO2 ratio, Sequential Organ Failure Assessment score, PREdiction of Survival on ECMO Therapy score, logistic regression, and 30 pre-selected clinical variables GBT Clinical GBT models, with area under the receiver operator curve (AUROC) and precision recall curve (AUPRC) metrics.

RESULTS

ECMO prevalence was 2.89% and 1.73% in development and holdout cohorts. ForecastECMO had the best performance in both cohorts. At the 18-h prediction horizon, a potentially clinically actionable pre-ECMO window, ForecastECMO, had the highest AUROC (0.94 and 0.95) and AUPRC (0.54 and 0.37) in development and holdout cohorts in identifying ECMO patients without data 18 h prior to ECMO.

DISCUSSION AND CONCLUSIONS

We developed a multi-horizon model, ForecastECMO, with high performance in identifying patients receiving ECMO at various prediction horizons. This model has potential to be used as early alert tool to guide ECMO resource allocation for COVID-19 patients. Future prospective multicenter validation would provide evidence for generalizability and real-world application of such models to improve patient outcomes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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 models for mortality risk in patients requiring ECMO

PURPOSE

To provide an overview and evaluate the performance of mortality prediction models for patients requiring extracorporeal membrane oxygenation (ECMO) support for refractory cardiocirculatory or respiratory failure.

METHODS

A systematic literature search was undertaken to identify studies developing and/or validating multivariable prediction models for all-cause mortality in adults requiring or receiving veno-arterial (V-A) or veno-venous (V-V) ECMO. Estimates of model performance (observed versus expected (O:E) ratio and c-statistic) were summarized using random effects models and sources of heterogeneity were explored by means of meta-regression. Risk of bias was assessed using the Prediction model Risk Of BiAS Tool (PROBAST).

RESULTS

Among 4905 articles screened, 96 studies described a total of 58 models and 225 external validations. Out of all 58 models which were specifically developed for ECMO patients, 14 (24%) were ever externally validated. Discriminatory ability of frequently validated models developed for ECMO patients (i.e., SAVE and RESP score) was moderate on average (pooled c-statistics between 0.66 and 0.70), and comparable to general intensive care population-based models (pooled c-statistics varying between 0.66 and 0.69 for the Simplified Acute Physiology Score II (SAPS II), Acute Physiology and Chronic Health Evaluation II (APACHE II) score and Sequential Organ Failure Assessment (SOFA) score). Nearly all models tended to underestimate mortality with a pooled O:E > 1. There was a wide variability in reported performance measures of external validations, reflecting a large between-study heterogeneity. Only 1 of the 58 models met the generally accepted Prediction model Risk Of BiAS Tool criteria of good quality. Importantly, all predicted outcomes were conditional on the fact that ECMO support had already been initiated, thereby reducing their applicability for patient selection in clinical practice.

CONCLUSIONS

A large number of mortality prediction models have been developed for ECMO patients, yet only a minority has been externally validated. Furthermore, we observed only moderate predictive performance, large heterogeneity between-study populations and model performance, and poor methodological quality overall. Most importantly, current models are unsuitable to provide decision support for selecting individuals in whom initiation of ECMO would be most beneficial, as all models were developed in ECMO patients only and the decision to start ECMO had, therefore, already been made.

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.

Evaluation of the discrimination and calibration of predictive scores of mortality in ECMO for patients with COVID-19

BACKGROUND

The criteria for the selection of COVID-19 patients that could benefit most from ECMO organ support are yet to be defined. In this study, we evaluated the predictive performance of ECMO mortality predictive models in patients with COVID-19. We also performed a cost-benefit analysis depending on the mortality predicted probability. We conducted a retrospective cohort study in COVID-19 patients who received ECMO at two tertiary care hospitals between March 2020 to July 2021.

MATERIALS AND METHODS

We evaluated the discrimination (C-statistic), calibration (Cox calibration), and accuracy of the prediction of death due to severe ARDS in V-V ECMO score (PRESERVE), the Respiratory Extracorporeal Membrane Oxygenation Survival Score (RESP) score, and the PREdiction of Survival on ECMO Therapy-Score (PRESET) score. In addition, we compared the RESP score with Plateau pressure instead of Peak pressure.

RESULTS

We included a total of 36 patients, 29 (80%) of them male and with a median (IQR) APACHE of 10 (8-15). The PRESET score had the highest discrimination (AUROCs 0.81 [95%CI 0.67-0.94]) and calibration (calibration-in-the-large 0.5 [95%CI -1.4 to 0.3]; calibration slope 2.2 [95%CI 0.7/3.7]). The RESP score with Plateau pressure had higher discrimination than the conventional RESP score. The cost per QALY in the USA, adjusted to life expectancy, was higher than USD 100 000 in patients older than 45 years with a PRESET > 10.

CONCLUSION

The PRESET score had the highest predictive performance and could help in the selection of patients that benefit most from this resource-demanding and highly invasive organ support.

A descriptive evaluation of causes of death in venovenous extracorporeal membrane oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become an important support modality for patients with acute respiratory failure refractory to optimal medical therapy, such as low tidal volume mechanical ventilator support, early paralytic infusion, and early prone positioning. The objective of this cohort study was to investigate the causes and timing of in-hospital mortality in patients on VV ECMO. All patients, excluding trauma and bridge to lung transplant, admitted 8/2014-6/2019 to a specialty ICU for VV ECMO were reviewed. Two hundred twenty-five patients were included. In-hospital mortality was 24.4% (n = 55). Most non-survivors (46/55, 84%) died prior to lung recovery and decannulation from VV ECMO. Most common cause of death (COD) for patients who died on VV ECMO was removal of life sustaining therapy (LST) in setting of multisystem organ failure (MSOF) (n = 24). Nine patients died a median of 9 days [6, 11] after decannulation. Most common COD in these patients was palliative withdrawal of LST due to poor prognosis (n = 3). Non-survivors were older and had worse predictive mortality scores than survivors. We found that death in patients supported with VV ECMO in our study most often occurs prior to decannulation and lung recovery. This study demonstrated that the most common cause of death in patients supported with VV ECMO was removal of LST due MSOF. Acute hemorrhage (systemic or intracranial) was not found to be a common cause of death in our patient population.

Time From Infiltrate on Chest Radiograph to Venovenous Extracorporeal Membrane Oxygenation in COVID-19 Affects Mortality

Venovenous extracorporeal membrane oxygenation (VV ECMO) has been used to treat severe coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome; however, patient selection criteria have evolved throughout the pandemic. In this study, we sought to determine the association of patient mortality with time from positive COVID-19 test and infiltrate on chest radiograph (x-ray) to VV ECMO cannulation. We hypothesized that an increasing duration between a positive COVID-19 test or infiltrates on chest x-ray and cannulation would be associated with increased mortality. This is a single-center retrospective chart review of COVID-19 VV ECMO patients from March 1, 2020 to July 28, 2021. Unadjusted and adjusted multivariate analyses were performed to assess for mortality differences. A total of 93 patients were included in our study. Increased time, in days, from infiltrate on chest x-ray to cannulation was associated with increased mortality in both unadjusted (5-9, P = 0.002) and adjusted regression analyses (odds ratio [OR]: 1.49, 95% CI: 1.22-1.81, P < 0.01). Time from positive test to cannulation was not found to be significant between survivors and nonsurvivors (7.5-11, P = 0.06). Time from infiltrate on chest x-ray to cannulation for VV ECMO should be considered when assessing patient candidacy. Further larger cohort and prospective studies are required.

Outcomes of Venovenous Extracorporeal Membrane Oxygenation in Viral Acute Respiratory Distress Syndrome

Our study assessed the relationship between the duration of venovenous extracorporeal membrane oxygenation (V-V ECMO) and patient outcomes. We studied patients undergoing V-V ECMO support for acute respiratory distress syndrome (ARDS) between 2009 and 2017 who were reported to the Extracorporeal Life Support Organization registry. We evaluated survival, major bleeding, renal failure, pulmonary complications, mechanical complications, neurologic complications, infection, and duration of V-V ECMO support. Multivariable regression modeling assessed risk factors for adverse events. Of the 4,636 patients studied, the mean support duration was 12.2 ± 13.7 days. There was a progressive increase in survival after the initiation of V-VECMO, peaking at a survival rate of 73% at 10 days of support. However, a single-day increase in V-V ECMO duration was associated with increased bleeding events (odds ratio [OR] 1.038; 95% confidence interval [CI]: 1.029-1.047; p < 0.0001), renal failure (OR 1.018; 95% CI: 1.010-1.027; p < 0.0001), mechanical complications (OR 1.065; 95% CI: 1.053-1.076; p < 0.0001), pulmonary complications (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001), and infection (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001). V-V ECMO progressively increases survival for ARDS over the first 10 days of support. Thereafter, rising complications associated with prolonged durations of support result in a progressive decline in survival.

Mortality prediction in pediatric postcardiotomy veno-arterial extracorporeal membrane oxygenation: A comparison of scoring systems

Background

Pediatric postcardiotomy veno-arterial extracorporeal membrane oxygenation (VA-ECMO) patients have high mortality and morbidity. There are currently three scoring systems available to predict mortality: the Pediatric Extracorporeal Membrane Oxygenation Prediction (PEP) model, Precannulation Pediatric Survival After VA-ECMO (Pedi-SAVE) score, and Postcannulation Pedi-SAVE score. These methods provide risk stratification scores for pediatric patients requiring ECMO for cardiac support. However, comparative validation of these scoring systems remains scarce. We aim to assess the ability of these models to predict outcomes in a cohort of pediatric patients undergoing VA-ECMO after cardiac surgery, and identify predictors of in-hospital mortality.

Methods

A retrospective analysis of 101 children admitted to Fuwai Hospital who received VA-ECMO from January 1, 2010 to December 31, 2020 was performed. Patients were divided into two groups, survivors (n = 49) and non-survivors (n = 52) according to in-hospital mortality. PEP model and Pedi-SAVE scores were calculated. The primary outcomes were the risk factors of in-hospital mortality, and the ability of the PEP model, Precannulation Pedi-SAVE and Postcannulation Pedi-SAVE scores to predict in-hospital mortality.

Results

Postcannulation Pedi-SAVE score accessing the entire ECMO process had the greatest area under receiver operator curve (AUROC), 0.816 [95% confidence interval (CI): 0.733–0.899]. Pre-ECMO PEP model could predict in-hospital mortality [AUROC = 0.691 (95% CI: 0.565–0.817)], and Precannulation Pedi-SAVE score had the poorest prediction [AUROC = 0.582(95% CI: 0.471–0.694)]. Lactate value at ECMO implantation [OR = 1.199 (1.064–1.351), P = 0.003] and infectious complications [OR = 5.169 (1.652–16.172), P = 0.005] were independent risk factors for in-hospital mortality.

Conclusion

Pediatric cardiac ECMO scoring systems, including multiple risk factors before and during ECMO, were found to be useful in this cohort. Both the pre-ECMO PEP model and the Postcannulation Pedi-SAVE score were found to have high predictive value for in-hospital mortality in pediatric postcardiotomy VA-ECMO.

The Year in Extracorporeal Membrane Oxygenation: Selected Highlights From 2021

This review summarizes the extracorporeal membrane oxygenation (ECMO) or extracorporeal life support literature published in 2021. This Selected Highlights article is not intended to be an exhaustive review of the literature, but rather a summarizing of key themes that developed in the ECMO literature during 2021. The primary topics presented include the following: ECMO for coronavirus disease 2019, extracorporeal cardiopulmonary resuscitation, periprocedural cardiopulmonary support with ECMO, and anticoagulation for ECMO.

Variations in mortality in Medicare recipients on extracorporeal membrane oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a rescue modality against severe cardiac and pulmonary compromise. We sought to assess variation in mortality and associated environmental and infrastructural predictors among Medicare beneficiaries on ECMO.

METHODS

We used Medicare claims data to evaluate hospitalizations between 2017 and 2019 during which beneficiaries required ECMO. The primary outcome of interest was mortality. We evaluated the influence on mortality of Medicare Case Mix Index (CMI), Medicare Wage Index, hospital size, ECMO cannulations, cardiology volume, region, and gender and modeled necessity and sufficiency relations involving ECMO volume, hospital size, cardiology volume, US region, and the mortality index through qualitative comparative analysis (QCA).

RESULTS

5368 ECMO cases were performed at 306 hospitals. Compared to institutions with a mortality index equal to or below 2, those above this threshold had statistically significant higher number of beds, cardiology volumes, and lower survival percentages (p < 0.05). Moreover, we observed a smaller proportion of institutions with an ECMO volume < 20 (78.3% vs 63.4%), which had mortality index > 2. The QCA analysis indicated that low cardiology volume and central/east location are necessary but not sufficient conditions for a mortality index above 2.

CONCLUSION

Trends in mortality are influenced by prevailing socioeconomic, utilization, infrastructural characteristics, and volume. As such, ECMO mortality may be more accurately predicted by models that account for more factors than clinical parameters alone.

Acute Kidney Injury in Patients with Severe ARDS Requiring Extracorporeal Membrane Oxygenation: Incidence, Prognostic Impact and Risk Factors

(1) Background: Acute kidney injury (AKI) is a common but under-investigated complication in patients receiving extracorporeal membrane oxygenation (ECMO). We aimed to define the incidence and clinical course, as well as the predictors of AKI in adults receiving ECMO support. (2) Materials and Methods: This is a retrospective analysis of all patients undergoing veno-venous ECMO treatment in a tertiary care center between December 2008 and December 2017. The primary endpoint was the new occurrence of an AKI of stage 2 or 3 according to the Kidney Disease: Improving Global Outcomes (KDIGO) classification after ECMO implantation. (3) Results: During the observation period, 103 patients underwent veno-venous ECMO implantation. In total, 59 patients (57.3%) met the primary endpoint with an AKI of stage 2 or 3 and 55 patients (53.4%) required renal replacement therapy. Patients with an AKI of 2 or 3 suffered from more bleeding and infectious complications. Whereas weaning failure from ECMO (30/59 (50.8%) vs. 15/44 (34.1%), p = 0.08) and 30-day mortality (35/59 (59.3%) vs. 17/44 (38.6%), p = 0.06) only tended to be higher in the group with an AKI of stage 2 or 3, long-term survival of up to five years was significantly lower in the group with an AKI of stage 2 or 3 (p = 0.015). High lactate, serum creatinine, and ECMO pump-speed levels, and low platelets, a low base excess, and a low hematocrit level before ECMO were independent predictors of moderate to severe AKI. Primary hypercapnic acidosis was more common in AKI non-survivors (12 (32.4%) vs. 0 (0.0%), p < 0.01). Accordingly, pCO2-levels prior to ECMO implantation tended to be higher in AKI non-survivors (76.12 ± 27.90 mmHg vs. 64.44 ± 44.31 mmHg, p = 0.08). In addition, the duration of mechanical ventilation prior to ECMO-implantation tended to be longer (91.14 ± 108.16 h vs. 75.90 ± 86.81 h, p = 0.078), while serum creatinine (180.92 ± 115.72 mmol/L vs. 124.95 ± 77.77 mmol/L, p = 0.03) and bicarbonate levels were significantly higher in non-survivors (28.22 ± 8.44 mmol/L vs. 23.36 ± 4.19 mmol/L, p = 0.04). (4) Conclusion: Two-thirds of adult patients receiving ECMO suffered from moderate to severe AKI, with a significantly increased morbidity and long-term mortality.

Veno-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure in adult cancer patients: a retrospective multicenter analysis

Purpose

The question of whether cancer patients with severe respiratory failure benefit from veno-venous extracorporeal membrane oxygenation (vv-ECMO) remains unanswered. We, therefore, analyzed clinical characteristics and outcomes of a large cohort of cancer patients treated with vv-ECMO with the aim to identify prognostic factors.

Methods

297 cancer patients from 19 German and Austrian hospitals who underwent vv-ECMO between 2009 and 2019 were retrospectively analyzed. A multivariable cox proportional hazards analysis for overall survival was performed. In addition, a propensity score-matched analysis and a latent class analysis were conducted.

Results

Patients had a median age of 56 (IQR 44–65) years and 214 (72%) were males. 159 (54%) had a solid tumor and 138 (47%) a hematologic malignancy. The 60-day overall survival rate was 26.8% (95% CI 22.1–32.4%). Low platelet count (HR 0.997, 95% CI 0.996–0.999; p = 0.0001 per 1000 platelets/µl), elevated lactate levels (HR 1.048, 95% CI 1.012–1.084; p = 0.0077), and disease status (progressive disease [HR 1.871, 95% CI 1.081–3.238; p = 0.0253], newly diagnosed [HR 1.571, 95% CI 1.044–2.364; p = 0.0304]) were independent adverse prognostic factors for overall survival. A propensity score-matched analysis with patients who did not receive ECMO treatment showed no significant survival advantage for treatment with ECMO.

Conclusion

The overall survival of cancer patients who require vv-ECMO is poor. This study shows that the value of vv-ECMO in cancer patients with respiratory failure is still unclear and further research is needed. The risk factors identified in the present analysis may help to better select patients who may benefit from vv-ECMO.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-022-06635-y.

MELD Score Predicts Outcomes in Patients Undergoing Venovenous Extracorporeal Membrane Oxygenation

Venovenous extracorporeal membrane oxygenation (VV ECMO) is increasingly being used in the management of severe acute respiratory distress syndrome (ARDS). The Respiratory ECMO Survival Prediction (RESP) score is most commonly used to predict survival of patients undergoing ECMO. However, the RESP score does not incorporate renal and hepatic dysfunction which are frequently a part of the constellation of multiorgan dysfunction associated with ARDS. The Model for End-Stage Liver Disease (MELD) incorporates both liver and kidney dysfunction and is used in the risk stratification of liver transplant recipients as well as those undergoing cardiac surgery. The aim of this study was to assess the prognostic value of the MELD score in patients undergoing VV ECMO. Patients undergoing VV ECMO from 2016 to 2019 were extracted from our prospectively maintained institutional ECMO database and stratified based on MELD score. Baseline clinical, laboratory, and follow-up data, as well as post-ECMO outcomes, were compared. Of 71 patients, 50 patients (70.4%) had a MELD score <12 and 21 (29.6%) had a MELD score ≥12. The higher MELD score was associated with increased post-ECMO mortality but reduced risk of dialysis and tracheostomy. In multivariate analysis, higher MELD score (HR 1.35, 95% CI = 1.07-2.75), lower body surface area (HR 0.16, 0.04-0.65), RESP score (HR 0.75, 95% CI = 0.64-0.87), and platelet count (HR 0.99, 95% CI = 0.98-0.99), were significant predictors of postoperative mortality. We conclude that MELD score can be used complementarily to the RESP score to predict outcomes in patients with ARDS undergoing VV ECMO.

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

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

Extracorporeal Membrane Oxygenation for COVID-19-associated Severe Acute Respiratory Distress Syndrome in Chile: A Nationwide Incidence and Cohort Study

Rationale: The role of and needs for extracorporeal membrane oxygenation (ECMO) at a population level during the coronavirus disease (COVID-19) pandemic have not been completely established. Objectives: To identify the cumulative incidence of ECMO use in the first pandemic wave and to describe the Nationwide Chilean cohort of ECMO-supported patients with COVID-19. Methods: We conducted a population-based study from March 3 to August 31, 2020, using linked data from national agencies. The cumulative incidence of ECMO use and mortality risk of ECMO-supported patients were calculated and age standardized. In addition, a retrospective cohort analysis was performed. Outcomes were 90-day mortality after ECMO initiation, ECMO-associated complications, and hospital length of stay. Cox regression models were used to explore risk factors for mortality in a time-to-event analysis. Measurements and Main Results: Ninety-four patients with COVID-19 were supported with ECMO (0.42 per population of 100,000, 14.89 per 100,000 positive cases, and 1.2% of intubated patients with COVID-19); 85 were included in the cohort analysis, and the median age was 48 (interquartile range [IQR], 41-55) years, 83.5% were men, and 42.4% had obesity. The median number of pre-ECMO intubation days was 4 (IQR, 2-7), the median Pa_O2/Fi_O2 ratio was 86.8 (IQR, 64-99) mm Hg, 91.8% of patients were prone positioned, and 14 patients had refractory respiratory acidosis. Main complications were infections (70.6%), bleeding (38.8%), and thromboembolism (22.4%); 52 patients were discharged home, and 33 died. The hospital length of stay was a median of 50 (IQR, 24-69) days. Lower respiratory system compliance and higher driving pressure before ECMO initiation were associated with increased mortality. A duration of pre-ECMO intubation ≥10 days was not associated with mortality. Conclusions: Documenting nationwide ECMO needs may help in planning ECMO provision for future COVID-19 pandemic waves. The 90-day mortality of the Chilean cohort of ECMO-supported patients with COVID-19 (38.8%) is comparable to that of previous reports.

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

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

Extracorporeal membrane oxygenation survival: External validation of current predictive scoring systems focusing on influenza A etiology

Despite increasing clinical experience with extracorporeal membrane oxygenation (ECMO), its optimal indications remain unclear. Here, we externally evaluated all currently available ECMO survival-predicting scoring systems and the APACHE II score in subjects undergoing veno-venous ECMO (VV ECMO) support due to acute respiratory distress syndrome (ARDS) with influenza (IVA) and non-influenza (n-IVA) etiologies. Our aim was to find the best scoring system for influenza A ARDS ECMO success prediction. Retrospective data were analyzed to assess the abilities of the PRESERVE, RESP, PRESET, ECMOnet, Roch, and APACHE II scores to predict patient outcome. Patients treated with veno-venous ECMO support for ARDS were divided into two groups: IVA and n-IVA etiologies. Parameters collected within 24 hours before ECMO initiation were used to calculate PRESERVE, RESP, PRESET, ECMOnet, Roch, and APACHE II scores. Compared to the IVA group, the n-IVA group exhibited significantly higher ICU, 28-day, and 6-month mortality (P = .043, .034, and .047, respectively). Regarding ECMO support success predictions, the area under the receiver operating characteristic curve (AUC) was 0.62 for PRESERVE, 0.44 for RESP, 0.57 for PRESET, and 0.67 for ECMOnet, and 0.62 for Roch calculated for all subjects according to the original papers. In the IVA group, APACHE II had the best predictive value for ICU, hospital, 28-day, and 6-month mortality (AUC values of 0.73, 0.73, 0.70, and 0.73, respectively). In the n-IVA group, APACHE II was the best predictor of survival in the ICU and hospital (AUC 0.54 and 0.57, respectively). From all possible ECMO survival scoring systems, the APACHE II score had the best predictive value for VV ECMO subjects with ARDS caused by influenza A-related pneumonia with a cut-off value of about 32 points.

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

Multiple prognostic scores have been developed for both veno-arterial (VA) and veno-venous (VV) extracorporeal membrane oxygenation (ECMO), mostly in single-center cohorts. The aim of this study was to compare and validate different prediction scores in a large multicenter ECMO-population. Methods: Data from five ECMO centers included 300 patients on VA and 329 on VV ECMO support (March 2008 to November 2016). Different prognostic scores were compared between survivors and non-survivors: APACHE II, SOFA, SAPS II in all patients; SAVE, modified SAVE and MELD-XI in VA ECMO; RESP, PRESET, ROCH and PRESERVE in VV ECMO. Model performance was compared using receiver-operating-curve analysis and assessment of model calibration. Survival was assessed at intensive care unit discharge. Results: The main indication for VA ECMO was cardiogenic shock; overall survival was 51%. ICU survivors had higher Glasgow Coma Scale scores and pH, required cardiopulmonary resuscitation (CPR) less frequently, had lower lactate levels and shorter ventilation time pre-ECMO at baseline. The best discrimination between survivors and non-survivors was observed with the SAPS II score (area under the curve [AUC] of 0.73 (95% CI 0.67–0.78)). The main indication for VV ECMO was pneumonia; overall survival was 60%. Lower PaCO₂, higher pH, lower lactate and lesser need for CPR were observed among survivors. The best discrimination between survivors and non-survivors was observed with the PRESET score (AUC 0.66 (95% CI 0.60–0.72)). Conclusion: The prognostic performance of most scores was moderate in ECMO patients. The use of such scores to decide about ECMO implementation in potential candidates should be discouraged.

Mortality Risk Assessment in COVID-19 Venovenous Extracorporeal Membrane Oxygenation

Background

A life-threatening complication of coronavirus disease 2019 (COVID-19) is acute respiratory distress syndrome (ARDS) refractory to conventional management. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) (VV-ECMO) is used to support patients with ARDS in whom conventional management fails. Scoring systems to predict mortality in VV-ECMO remain unvalidated in COVID-19 ARDS. This report describes a large single-center experience with VV-ECMO in COVID-19 and assesses the utility of standard risk calculators.

Methods

A retrospective review of a prospective database of all patients with COVID-19 who underwent VV-ECMO cannulation between March 15 and June 27, 2020 at a single academic center was performed. Demographic, clinical, and ECMO characteristics were collected. The primary outcome was in-hospital mortality; survivor and nonsurvivor cohorts were compared by using univariate and bivariate analyses.

Results

Forty patients who had COVID-19 and underwent ECMO were identified. Of the 33 patients (82.5%) in whom ECMO had been discontinued at the time of analysis, 18 patients (54.5%) survived to hospital discharge, and 15 (45.5%) died during ECMO. Nonsurvivors presented with a statistically significant higher Prediction of Survival on ECMO Therapy (PRESET)-Score (mean ± SD, 8.33 ± 0.8 vs 6.17 ± 1.8; P = .001). The PRESET score demonstrated accurate mortality prediction. All patients with a PRESET-Score of 6 or lowers survived, and a score of 7 or higher was associated with a dramatic increase in mortality.

Conclusions

These results suggest that favorable outcomes are possible in patients with COVID-19 who undergo ECMO at high-volume centers. This study demonstrated an association between the PRESET-Score and survival in patients with COVID-19 who underwent VV-ECMO. Standard risk calculators may aid in appropriate selection of patients with COVID-19 ARDS for ECMO.

Veno-venous extracorporeal membrane oxygenation allocation in the COVID-19 pandemic

Rapid global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resultant clinical illness, coronavirus disease 2019 (COVID-19), drove the World Health Organization to declare COVID-19 a pandemic. Veno-venous Extra-Corporeal Membrane Oxygenation (VV-ECMO) is an established therapy for management of patients demonstrating the most severe forms of hypoxemic respiratory failure from COVID-19. However, features of COVID-19 pathophysiology and necessary length of treatment present distinct challenges for utilization of VV-ECMO within the current healthcare emergency. In addition, growing allocation concerns due to capacity and cost present significant challenges. Ethical and legal aspects pertinent to triage of this resource-intensive, but potentially life-saving, therapy in the setting of the COVID-19 pandemic are reviewed here. Given considerations relevant to VV-ECMO use, additional emphasis has been placed on emerging hospital resource scarcity and disproportionate representation of healthcare workers among the ill. Considerations are also discussed surrounding withdrawal of VV-ECMO and the role for early communication as well as consultation from palliative care teams and local ethics committees. In discussing how to best manage these issues in the COVID-19 pandemic at present, we identify gaps in the literature and policy important to clinicians as this crisis continues.

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VV-ECMO may successfully treat respiratory failure due to COVID-19.

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The coronavirus pandemic necessitates judicious use of this resource-intensive therapy.

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Unique features of COVID-19, including isolation from surrogates, present challenges.

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Providers face difficult triage decisions that must be communicated appropriately.

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We review available resources and support tools for clinicians considering VV-ECMO.

Optimization of extracorporeal membrane oxygenation therapy using near-infrared spectroscopy to assess changes in peripheral circulation: A pilot study

Near-infrared spectroscopy (NIRS) has been proposed as a noninvasive modality for detecting complications in patients undergoing extracorporeal membrane oxygenation (ECMO), and it can simultaneously reveal the global circulatory status of these patients. We optimized ECMO therapy on the basis of real-time peripheral NIRS probing. Three patients underwent venoarterial (VA) ECMO and one patient underwent venovenous (VV) ECMO. All patients received peripheral ECMO cannulation with routine distal perfusion catheter placement. We designed an experimental protocol to adjust ECMO blood flow over 1 hour. Hemodynamic responses were measured using NIRS devices attached to the calf at approximately 60% of the distance from the ankle to the knee. HbO₂ levels change substantially with adjustments in ECMO flow, and they are more sensitive than HHb levels and the tissue saturation index (TSI) are. NIRS for optimizing ECMO therapy may be reliable for monitoring global circulatory status.

A Case of Extracorporeal Membrane Oxygenation as a Salvage Therapy for COVID-19-Associated Severe Acute Respiratory Distress Syndrome: Mounting Evidence

Coronavirus disease 2019 (COVID-19) caused by a novel human coronavirus has led to a tsunami of viral illness across the globe, originating from Wuhan, China. Although the value and effectiveness of extracorporeal membrane oxygenation (ECMO) in severe respiratory illness from COVID-19 remains unclear at this time, there is emerging evidence suggesting that it could be utilized as an ultimate treatment in appropriately selected patients not responding to conventional care. We present a case of a 32-year-old COVID-19 positive male with a history of diabetes mellitus who was intubated for severe acute respiratory distress syndrome (ARDS). The patient's hypoxemia failed to improve despite positive pressure ventilation, prone positioning, and use of neuromuscular blockade for ventilator asynchrony. He was evaluated by a multidisciplinary team for considering ECMO for refractory ARDS. He was initiated on venovenous ECMO via dual-site cannulation performed at the bedside. Although his ECMO course was complicated by bleeding, he showed a remarkable improvement in his lung function. ECMO was successfully decannulated after 17 days of initiation. The patient was discharged home after 47 days of hospitalization without any supplemental oxygen and was able to undergo active physical rehabilitation. A multidisciplinary approach is imperative in the initiation and management of ECMO in COVID-19 patients with severe ARDS. While ECMO is labor-intensive, using it in the right phenotype and in specialized centers may lead to positive results. Patients who are young, with fewer comorbidities and single organ dysfunction portray a better prognosis for patients in which ECMO is utilized.

Outcomes of Venovenous Extracorporeal Membrane Oxygenation When Stratified by Age: How Old Is Too Old?

The purpose of this study was to evaluate survival to hospital discharge for patients on venovenous extracorporeal membrane oxygenation (VV ECMO) when stratified by age. We performed a retrospective study at single, academic, tertiary care center intensive care unit for VV ECMO. All patients, older than 17 years of age, on VV ECMO admitted to a specialized intensive care unit for the management of VV ECMO between August 2014 and May 2018 were included in the study. Trauma and bridge-to-lung transplant patients were excluded for this analysis. Demographics, pre-ECMO and ECMO data were collected. Primary outcome was survival to hospital discharge when stratified by age. Secondary outcomes included time on VV ECMO and hospital length of stay (HLOS). One hundred eighty-two patients were included. Median P/F ratio at time of cannulation was 69 [56-85], and respiratory ECMO survival prediction (RESP) score was 3 [1-5]. Median time on ECMO was 319 [180-567] hours. Overall survival to hospital discharge was 75.8%. Lowess and cubic spline curves demonstrated an inflection point associated with increased mortality at age >45 years. Kaplan-Meier analysis demonstrated significantly greater survival in patients <45 years of age (p = 0.0001). Survival to hospital discharge for those Collapse

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MESH Headings

• Adult
• Age Factors
• Aged
• Extracorporeal Membrane Oxygenation/mortality
• Female
• Hospital Mortality
• Humans
• Kaplan-Meier Estimate
• Length of Stay/statistics & numerical data
• Male
• Middle Aged
• Respiratory Insufficiency/therapy
• Retrospective Studies

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Affiliation(s)

Kristopher B Deatrick From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
Michael A Mazzeffi Department of Anesthesia, Program in Trauma, R Adams Cowley Shock Trauma Center, Baltimore, Maryland
Samuel M Galvagno Department of Anesthesia, Program in Trauma, R Adams Cowley Shock Trauma Center, Baltimore, Maryland
Ronald B Tesoriero From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
David J Kaczoroswki From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
Daniel L Herr From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
Katelyn Dolly University of Maryland Medical Center, Baltimore, Maryland
Ronald P Rabinowitz Department of Medicine, Baltimore, Maryland
Thomas M Scalea From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
Jay Menaker From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland

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Extracorporeal Membrane Oxygenation for Severe Respiratory Failure During Respiratory Epidemics and Pandemics: A Narrative Review

Introduction: Epidemics and pandemics from zoonotic respiratory viruses, such as the 2019 novel coronavirus, can lead to significant global intensive care burden as patients progress to acute respiratory distress syndrome (ARDS). A subset of these patients develops refractory hypoxaemia despite maximal conventional mechanical ventilation and require extracorporeal membrane oxygenation (ECMO). This review focuses on considerations for ventilatory strategies, infection control and patient selection related to ECMO for ARDS in a pandemic. We also summarise the experiences with ECMO in previous respiratory pandemics. Materials and Methods: A review of pertinent studies was conducted via a search using MEDLINE, EMBASE and Google Scholar. References of articles were also examined to identify other relevant publications. Results: Since the H1N1 Influenza pandemic in 2009, the use of ECMO for ARDS continues to grow despite limitations in evidence for survival benefit. There is emerging evidence to suggest that lung protective ventilation for ARDS can be further optimised while receiving ECMO so as to minimise ventilator-induced lung injury and subsequent contributions to multi-organ failure. Efforts to improve outcomes should also encompass appropriate infection control measures to reduce co-infections and prevent nosocomial transmission of novel respiratory viruses. Patient selection for ECMO in a pandemic can be challenging. We discuss important ethical considerations and predictive scoring systems that may assist clinical decision-making to optimise resource allocation. Conclusion: The role of ECMO in managing ARDS during respiratory pandemics continues to grow. This is supported by efforts to redefine optimal ventilatory strategies, reinforce infection control measures and enhance patient selection. Ann Acad Med Singapore 2020;49:199–214 Key words: Acute Respiratory Distress Syndrome, Coronavirus disease 2019, ECMO, Infection control, Mechanical ventilation