Developing a simple preinterventional score to predict hospital mortality in adult venovenous extracorporeal membrane oxygenation: A pilot study

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.

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.

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.

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.

Outcome of post-traumatic acute respiratory distress syndrome in young patients requiring extracorporeal membrane oxygenation (ECMO)

We aimed to evaluate the outcomes of post-traumatic acute respiratory distress syndrome (ARDS) in young patients with and without Extracorporeal membrane oxygenation (ECMO) support. A retrospective analysis was conducted for trauma patients who developed ARDS at a level I trauma facility between 2014 and 2020. Data were analyzed and compared between ECMO and non-ECMO group. We identified 85 patients with ARDS (22 patients had ECMO support and 63 matched patients managed by the conventional mechanical ventilation; 1:3 matching ratio). The two groups were comparable for age, sex, injury severity score, abbreviated injury score, shock index, SOFA score, and head injury. Kaplan Meier survival analysis showed that the survival in the ECMO group was initially close to that of the non-ECMO, however, during follow-up, the survival rate was better in the ECMO group, but did not reach statistical significance (Log-rank, p = 0.43 and Tarone-Ware, p = 0.37). Multivariable logistic regression analysis showed that acute kidney injury (AKI) (Odds ratio 13.03; 95% CI 3.17–53.54) and brain edema (Odds ratio 4.80; 95% CI 1.10–21.03) were independent predictors of mortality. Sub-analysis showed that in patients with severe Murray Lung Injury (MLI) scores, non-ECMO group had higher mortality than the ECMO group (100% vs 36.8%, p = 0.004). Although ARDS is uncommon in young trauma patients, it has a high mortality. ECMO therapy was used in a quarter of ARDS cases. AKI and brain edema were the predictors of mortality among ARDS patients. ECMO use did not worsen the outcome in trauma patients; however, the survival was better in those who had severe MLI and ECMO support. Further prospective study is needed to define the appropriate selection criteria for the use of ECMO to optimize the outcomes in trauma patients.

Defining and understanding the "extra-corporeal membrane oxygenation gap" in the veno-venous configuration: Timing and causes of death

In‐hospital mortality of adult veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) patients remains invariably high. However, little is known regarding timing and causes of in‐hospital death, either on‐ECMO or after weaning. The current review aims to investigate the timing and causes of death of adult patients during hospital admittance for V‐V ECMO, and to define the V‐V ECMO gap, which is represented by the patients that are successfully weaned of ECMO but still die during hospital stay. A systematic search was performed using electronic MEDLINE and EMBASE databases through PubMed. Studies reporting on adult V‐V ECMO patients from January 2006 to December 2020 were screened. Studies that did not report on at least on‐ECMO mortality and discharge rate were excluded from analysis as they could not provide the required information regarding the proposed V‐V ECMO‐gap. Mortality rates on‐ECMO and after weaning, as well as weaning and discharge rates, were analyzed as primary outcomes. Secondary outcomes were the causes of death and complications. Initially, 35 studies were finally included in this review. Merely 24 of these studies (comprising 975 patients) reported on prespecified V‐V ECMO outcomes (on‐ECMO mortality and discharge rate). Mortality on V‐V ECMO support was 27.8% (95% confidence interval (CI) 22.5%‐33.2%), whereas mortality after successful weaning was 12.7% (95% CI 8.8%‐16.6%, defining the V‐V ECMO gap). 72.2% of patients (95% CI 66.8%‐77.5%) were weaned successfully from support and 56.8% (95% CI 49.9%‐63.8%) of patients were discharged from hospital. The most common causes of death on ECMO were multiple organ failure, bleeding, and sepsis. Most common causes of death after weaning were multiorgan failure and sepsis. Although the majority of patients are weaned successfully from V‐V ECMO support, a significant proportion of subjects still die during hospital stay, defining the V‐V ECMO gap. Overall, timing and causes of death are poorly reported in current literature. Future studies on V‐V ECMO should describe morbidity and mortality outcomes in more detail in relation to the timing of the events, to improve patient management, due to enhanced understanding of the clinical course.

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 Support Prognostication-Time to Move the Goal Posts?

Advances in extracorporeal membrane oxygenation (ECMO) technology are associated with expanded indications, increased utilization and improved outcome. There is growing interest in developing ECMO prognostication scores to aid in bedside decision making. To date, the majority of available scores have been limited to mostly registry-based data and with mortality as the main outcome of interest. There continues to be a gap in clinically applicable decision support tools to aid in the timing of ECMO cannulation to improve patients' long-term outcomes. We present a brief review of the commonly available adult and pediatric ECMO prognostication tools, their limitations, and future directions.

Basics of extra corporeal membrane oxygenation: a pediatric intensivist's perspective

Extra Corporeal membrane oxygenation (ECMO) is one of the most advanced forms of life support therapy in the Intensive Care Unit. It relies on the principle where an external artificial circuit carries venous blood from the patient to a gas exchange device (oxygenator) within which blood becomes enriched with oxygen and has carbon dioxide removed. The blood is then returned to the patient via a central vein or an artery. The goal of ECMO is to provide a physiologic milieu for recovery in refractory cardiac/respiratory failure. The technology is not a definitive treatment for a disease, but provides valuable time for the body to recover. In that way it can be compared to a bridge, where patients are initiated on ECMO as a bridge to recovery, bridge to decision making, bridge to transplant or bridge to diagnosis. The use of this modality in children is not backed by a lot of randomized controlled trials, but the use has increased dramatically in our country in last 10 years. This article is not intended to provide an in-depth overview of ECMO, but outlines the basic principles that a pediatric intensive care physician should know in order to manage a kid on ECMO support.

Venovenous ECMO treatment, outcomes, and complications in adults according to large case series: A systematic review

Background:

Venovenous extracorporeal membrane oxygenation (VV ECMO) has gained popularity for the treatment of refractory respiratory failure during and after the 2009 influenza pandemic, and still represents a precious therapeutic resource for severe novel coronavirus 2019 infection. However, most of the published studies are small case series, and only two randomized trials exist in literature.

Aim:

Aim of this systematic review is to describe trends in VV ECMO treatment outcomes according to large studies only.

Methods:

We searched and included studies with more than 100 VV ECMO cases dated up to August 1st, 2019.

Results:

Thirty-three studies published in the period 2011–2019 met inclusion criteria, for a total of 12,860 patients (age 46.3 ± 17.4 years). ARDS was mainly by pneumonia, in 3126 (37%) cases; further 401(7%) patients had H1N1 Influenza A infection. Cannulation-related complications occurred in 502 (7%) cases. Weighted mean (95% confidence interval) of VV ECMO duration was 8.9 (8.7–9.1) days, and ICU stay was 23.6 (22.4–24.8) days. Mortality at the longest follow up available was 40%. Data collection in 70% of the studies had a duration of >5 years.

Conclusion:

This study reveals the characteristics of large case VV ECMO studies.

Prediction of outcome in patients with ARDS: A prospective cohort study comparing ARDS-definitions and other ARDS-associated parameters, ratios and scores at intubation and over time

Background

Early recognition of high-risk-patients with acute respiratory distress syndrome (ARDS) might improve their outcome by less protracted allocation to intensified therapy including extracorporeal membrane oxygenation (ECMO). Among numerous predictors and classifications, the American European Consensus Conferenece (AECC)- and Berlin-definitions as well as the oxygenation index (OI) and the Murray-/Lung Injury Score are the most common. Most studies compared the prediction of mortality by these parameters on the day of intubation and/or diagnosis of ARDS. However, only few studies investigated prediction over time, in particular for more than three days.

Objective

Therefore, our study aimed at characterization of the best predictor and the best day(s) to predict 28-days-mortality within four days after intubation of patients with ARDS.

Methods

In 100 consecutive patients with ARDS severity according to OI (mean airway pressure*F_iO₂/p_aO₂), modified Murray-score without radiological points (Murray_mod), AECC- and Berlin-definition, were daily documented for four days after intubation. In the subgroup of 49 patients with transpulmonary thermodilution (TPTD) monitoring (PiCCO), extravascular lung water index (EVLWI) was measured daily.

Primary endpoint

Prediction of 28-days-mortality (Area under the receiver-operating-characteristic curve (ROC-AUC)); IBM SPSS 26.

Results

In the totality of patients the best prediction of 28-days-mortality was found on day-1 and day-2 (mean ROC-AUCs for all predictors/scores: 0.632 and 0.620). OI was the best predictor among the ARDS-scores (AUC=0.689 on day-1; 4-day-mean AUC = 0.625). AECC and Murray_mod had 4-day-means AUCs below 0.6. Among the 49 patients with TPTD, EVLWI (4-day-mean AUC=0.696) and OI (4-day-mean AUC=0.695) were the best predictors. AUCs were 0.789 for OI on day-1, and 0.786 for EVLWI on day-2. In binary regression analysis of patients with TPTD, EVLWI (B=-0.105; Wald=7.294; p=0.007) and OI (B=0.124; Wald=7.435; p=0.006) were independently associated with 28-days-mortality. Combining of EVLWI and OI provided ROC-AUCs of 0.801 (day-1) and 0.824 (day-2). Among the totality of patients, the use of TPTD-monitoring „per se“ and a lower SOFA-score were independently associated with a lower 28-days-mortality.

Conclusions

Prognosis of ARDS-patients can be estblished within two days after intubation. The best predictors were EVLWI and OI and their combination. TPTD-monitoring „per se“ was independently associated with reduced mortality.

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

Ethical Considerations for Mechanical Support

Extracorporeal life support can support patients with severe forms of cardiac and respiratory failure. Uncertainty remains about its optimal use owing in large part to its resource-intensive nature and the high acuity illness in supported patients. Specific issues include the identification of patients most likely to benefit, the appropriate duration of support when prognosis is uncertain, and what to do when patients become dependent on extracorporeal life support but no longer have hope for recovery or transplantation. Careful deliberation of ethical principles and potential dilemmas should be made when considering the use of extracorporeal life support in advanced cardiopulmonary failure.

[ECMO treatment in acute lung failure : Who profits?]

In intensive care medicine, rapid technical developments that are often beneficial to patients are taking place. On the other hand, there are also voices that generally criticize an increasing "interventionalism". This area of tension includes other important questions regarding usefulness, quality, ethical compliance, scientific evidence, structural capacities and economy. The treatment of acute respiratory distress syndrome (ARDS) using extracorporeal membrane oxygenation (ECMO) is an example of these considerations. Although ECMO has rarely been prospectively evaluated according to scientific criteria, it is still used with an increasing tendency, not least since the documented register survival rates in ECMO patients with severe ARDS are 60%. However, the implementation of this therapy means an immense effort. The necessary centralization and certification for ECMO treatment is currently under intensive discussion. Closely related to this are considerations about which criteria represent good quality in patient care. In order to be able to guarantee high quality, a precise indication is the first step. And here indications and contraindications still need to be defined. It has not yet been sufficiently clarified which prognosis factors need to be taken into account. This article summarizes what is known about ECMO prognosis and indication criteria. In conclusion, parameters are identified that should be developed scientifically in the future.

Six-Month Outcome of Immunocompromised Patients with Severe Acute Respiratory Distress Syndrome Rescued by Extracorporeal Membrane Oxygenation. An International Multicenter Retrospective Study

Rationale: Because encouraging rates for hospital and long-term survival of immunocompromised patients in ICUs have been described, these patients are more likely to receive invasive therapies, like extracorporeal membrane oxygenation (ECMO).Objectives: To report outcomes of immunocompromised patients treated with ECMO for severe acute respiratory distress syndrome (ARDS) and to identify their pre-ECMO predictors of 6-month mortality and main ECMO-related complications.Methods: Retrospective multicenter study in 10 international ICUs with high volumes of ECMO cases. Immunocompromised patients, defined as having hematological malignancies, active solid tumor, solid-organ transplant, acquired immunodeficiency syndrome, or long-term or high-dose corticosteroid or immunosuppressant use, and severe ECMO-treated ARDS, from 2008 to 2015 were included.Measurements and Main Results: We collected demographics, clinical data, ECMO-related complications, and ICU- and 6 month-outcome data for 203 patients (median Acute Physiology and Chronic Health Evaluation II score, 28 [25th-75th percentile, 20-33]; age, 51 [38-59] yr; Pa_O2/Fi_O2, 60 [50-82] mm Hg before ECMO) who fulfilled our inclusion criteria. Six-month survival was only 30%, with a respective median ECMO duration and ICU stay of 8 (5-14) and 25 (16-50) days. Patients with hematological malignancies had significantly poorer outcomes than others (log-rank P = 0.02). ECMO-related major bleeding, cannula infection, and ventilator-associated pneumonia were frequent (36%, 10%, and 50%, respectively). Multivariate analyses retained fewer than 30 days between immunodeficiency diagnosis and ECMO cannulation as being associated with lower 6-month mortality (odds ratio, 0.32 [95% confidence interval, 0.16-0.66]; P = 0.002), and lower platelet count, higher Pco₂, age, and driving pressure as independent pre-ECMO predictors of 6-month mortality.Conclusions: Recently diagnosed immunodeficiency is associated with a much better prognosis in ECMO-treated severe ARDS. However, low 6-month survival of our large cohort of immunocompromised patients supports restricting ECMO to patients with realistic oncological/therapeutic prognoses, acceptable functional status, and few pre-ECMO mortality-risk factors.

Predictors of hospital mortality in adult trauma patients receiving extracorporeal membrane oxygenation for advanced life support: a retrospective cohort study

Background

Using extracorporeal membrane oxygenation (ECMO) to provide advanced life support in adult trauma patients remains a controversial issue now. The study was aimed at identifying the independent predictors of hospital mortality in adult trauma patients receiving ECMO for advanced cardiopulmonary dysfunctions.

Methods

This retrospective study enrolled 36 adult trauma patients receiving ECMO due to advanced shock or respiratory failure in a level I trauma center between August 2006 and October 2014. Variables collected for analysis were demographics, serum biomarkers, characteristics of trauma, injury severity score (ISS), damage-control interventions, indications of ECMO, and associated complications. The outcomes were hospital mortality and hemorrhage on ECMO. The multivariate logistic regression method was used to identify the independent prognostic predictors for the outcomes.

Results

The medians of age and ISS were 36 (27–49) years and 29 (19–45). Twenty-three patients received damage-control interventions before ECMO. Among the 36 trauma patients, 14 received ECMO due to shock and 22 for respiratory failure. The complications of ECMO are major hemorrhages (n = 12), acute renal failure requiring hemodialysis (n = 10), and major brain events (n = 7). There were 15 patients died in hospital, and 9 of them were in the shock group.

Conclusions

The severity of trauma and the type of cardiopulmonary dysfunction significantly affected the outcomes of ECMO used for sustaining patients with post-traumatic cardiopulmonary dysfunction. Hemorrhage on ECMO remained a concern while the device was required soon after trauma, although a heparin-minimized protocol was adopted.

Trial registration

This study reported a health care intervention on human participants and was retrospectively registered. The Chang Gung Medical Foundation Institutional Review Board approved the study (no. 201601610B0) on December 12, 2016. All of the data were extracted from December 14, 2016, to March 31, 2017.

A novel risk score for severe ARDS patients undergoing ECMO after retrieval from peripheral hospitals

BACKGROUND

Extracorporeal Membrane Oxygenation in severe ARDS unresponsive to conventional protective ventilation is associated with elevated costs, resource and complications, and appropriate risk stratification of candidate patients could be useful to recognize those more likely to benefit from ECMO. We aimed to derive a new outcome prediction score for patients retrieved by our ECMO team from peripheral centers, including systematic echocardiographic evaluation before ECMO start.

METHODS

Sixty-nine consecutive patients with refractory ARDS requiring ECMO transferred from peripheral centers to our ICU (a tertiary ECMO referral center), from 1 October 2009 to 31 December 2015, were assessed.

RESULTS

All patients were transported on ECMO (distance, median 77, range 4-456 km) The mortality rate was 41% (28/69). Our new risk score included age ≥ 42 years, BMI < 31 kg/m² , RV dilatation, and pH < 7.35. The proposed cut off (Youden's index method) of nine had a sensitivity of 96% and a specificity of 30% (AUC-ROC: 0.85, 95% CI: 0.76-0.94, P < 0.001). When assessing the discriminatory ability of our risk score in the population of local patients, survivors had a mean value of 15.4 ± 8.6, whereas non-survivors showed a mean value of 20.1 ± 7.4 (P < 0.001).

CONCLUSIONS

Our new risk score shows good discriminatory ability both in patients retrieved from peripheral centers and in those implanted at our center. This score includes variables easily available at bedside, and, for the first time, a pathophysiologic element, RV dilatation.

The impacts of baseline ventilator parameters on hospital mortality in acute respiratory distress syndrome treated with venovenous extracorporeal membrane oxygenation: a retrospective cohort study

BACKGROUND

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a valuable life support in acute respiratory distress syndrome (ARDS) in adult patients. However, the success of VV-ECMO is known to be influenced by the baseline settings of mechanical ventilation (MV) before its institution. This study was aimed at identifying the baseline ventilator parameters which were independently associated with hospital mortality in non-trauma patients receiving VV-ECMO for severe ARDS.

METHODS

This retrospective study included 106 non-trauma patients (mean age: 53 years) who received VV-ECMO for ARDS in a single medical center from 2007 to 2016. The indication of VV-ECMO was severe hypoxemia (P_aO₂/ FiO₂ ratio < 70 mmHg) under pressure-controlled MV with peak inspiratory pressure (PIP) > 35 cmH₂O, positive end-expiratory pressure (PEEP) > 5 cmH₂O, and F_iO₂ > 0.8. Important demographic and clinical data before and during VV-ECMO were collected for analysis of hospital mortality.

RESULTS

The causes of ARDS were bacterial pneumonia (n = 41), viral pneumonia (n = 24), aspiration pneumonitis (n = 3), and others (n = 38). The median duration of MV before ECMO institution was 3 days and the overall hospital mortality was 53% (n = 56). The medians of PaO₂/ FiO₂ ratio, PIP, PEEP, and dynamic pulmonary compliance (PC_dyn) at the beginning of MV were 84 mmHg, 32 cmH₂O, 10 cmH₂O, and 21 mL/cmH₂O, respectively. However, before the beginning of VV-ECMO, the medians of PaO₂/ FiO₂ ratio, PIP, PEEP, and PC_dyn became 69 mmHg, 36 cmH₂O, 14 cmH₂O, and 19 mL/cmH₂O, respectively. The escalation of PIP and the declines in PaO₂/ FiO₂ ratio and PC_dyn were significantly correlated with the duration of MV before ECMO institution. Finally, the duration of MV (OR: 1.184, 95% CI: 1.079-1.565, p < 0.001) was found to be the only baseline ventilator parameter that independently affected the hospital mortality in these ECMO-treated patients.

CONCLUSION

Since the duration of MV before ECMO institution was strongly correlated to the outcome of adult respiratory ECMO, medical centers are suggested to find a suitable prognosticating tool to determine the starting point of respiratory ECMO among their candidates with different duration of MV.

TRIAL REGISTRATION

This study reported a health care intervention on human participants and was retrospectively registered. The Chang Gung Medical Foundation Institutional Review Board approved the study (no. 201601483B0 ) on November 23, 2016. All of the data were extracted from December 1, 2016, to January 31, 2017.

Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure

Conventionally, a substantial number of patients with acute respiratory failure require mechanical ventilation (MV) to avert catastrophe of hypoxemia and hypercapnia. However, mechanical ventilation per se can cause lung injury, accelerating the disease progression. Extracorporeal membrane oxygenation (ECMO) provides an alternative to rescue patients with severe respiratory failure that conventional mechanical ventilation fails to maintain adequate gas exchange. The physiology behind ECMO and its interaction with MV were reviewed. Next, we discussed the timing of ECMO initiation based on the risks and benefits of ECMO. During the running of ECMO, the protective ventilation strategy can be employed without worrying about catastrophic hypoxemia and carbon dioxide retention. There is a large body of evidence showing that protective ventilation with low tidal volume, high positive end-expiratory pressure, and prone positioning can provide benefits on mortality outcome. More recently, there is an increasing popularity on the use of awake and spontaneous breathing for patients undergoing ECMO, which is thought to be beneficial in terms of rehabilitation.

Outcomes and survival prediction models for severe adult acute respiratory distress syndrome treated with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) has known a growing interest over the last decades with promising results during the 2009 A(H1N1) influenza epidemic. Targeting populations that can most benefit from this therapy is now of major importance.

Survival has steadily improved for a decade, reaching up to 65% at hospital discharge in the most recent cohorts. However, ECMO is still marred by frequent and significant complications such as bleeding and nosocomial infections. In addition, physiological and psychological symptoms are commonly described in long-term follow-up of ECMO-treated ARDS survivors. Because this therapy is costly and exposes patients to significant complications, seven prediction models have been developed recently to help clinicians identify patients most likely to survive once ECMO has been initiated and to facilitate appropriate comparison of risk-adjusted outcomes between centres and over time. Higher age, immunocompromised status, associated extra-pulmonary organ dysfunction, low respiratory compliance and non-influenzae diagnosis seem to be the main determinants of poorer outcome.