Epidemiology and volume-outcome relationship of extracorporeal membrane oxygenation for respiratory failure in Japan: A retrospective observational study using a national administrative database

Response on Rapid Review to Inform Policy Guidance on Welsh Respiratory ECMO Provision

Internationally, extracorporeal membrane oxygenation (ECMO) is now a core and standard organ support tool to provide tertiary critical care and cardiac services within a network of hospitals and a key tool for running an effective and efficient cardio-respiratory pathways. The letter aims to put the spotlight on some of the missing clinical evidence on respiratory ECMO and including them will help to arrive at a better-informed national ECMO policy decision.

ECMO for Adult Respiratory Failure: A Rapid Review of Clinical and Service Delivery Evidence to Guide Policy in Wales

BACKGROUND

While several studies have summarised the clinical effectiveness evidence for extracorporeal membrane oxygenation (ECMO), there are no evidence syntheses of the impact of centres' ECMO patient volume on patient outcomes or the impact of bedside ECMO care being delivered by either a perfusionist or a nurse. There is also limited information on the cost-effectiveness of ECMO.

PURPOSE

This review was carried out to evaluate the clinical effectiveness and cost of different service delivery models of pulmonary ECMO to inform NHS Wales commissioning policy.

RESEARCH DESIGN

The study utilised rapid review methodology, consisting of a systematic literature search and the inclusion of the highest quality of evidence available.

DATA COLLECTION

Out of 1997 records identified via literature searches, 12 studies fell within the scope. The 2 meta-analyses comparing ECMO with lung-protective ventilation favoured ECMO.

RESULTS

Five studies looking at the clinical impact of centre patient volume had large heterogeneity. Three studies estimated that with sufficient patient volume, nurse-delivered ECMO was cost-saving, with thresholds varying between 92 and 155 patient days per year. Three studies looked at the cost impact of ECMO delivery, with ECMO being cost incurring, but potentially cost-effective, with costs per patient being lower at higher volume centres.

CONCLUSIONS

The available evidence supports the use of ECMO in adult respiratory failure patients, despite it being cost-incurring. ECMO can be nurse-delivered without a significant negative impact on patient care. Yet decision-makers need to consider their local circumstances when making commissioning decisions.

Hospital-level volume in extracorporeal membrane oxygenation cases and death or disability at 6 months

Objective

Extracorporeal membrane oxygenation (ECMO) is a high-risk procedure with significant morbidity and mortality and there is an uncertain volume-outcome relationship, especially regarding long-term functional outcomes. The aim of this study was to examine the association between ECMO centre volume and long-term death and disability outcomes.

Design setting and participants

This is a registry-embedded observational cohort study. Patients were included if they were enrolled in the binational ECMO registry (EXCEL). The exclusion criteria included patients on ECMO for heart/lung transplants. Data included demographics, clinical information on their first ECMO run, and six-month outcomes obtained by telephone interview. The primary outcome was death or new disability at six months. A multivariable analysis was conducted using hospitals' annual ECMO volume. High-volume centres were defined as having >30 ECMO cases annually, and analyses were run on ECMO subgroups of veno-venous (VV), veno-arterial (VA), and extracorporeal cardiopulmonary resuscitation (ECPR).

Results

Of 1232 patients, 663 patients were cared for on ECMO at high-volume centres and 569 patients at low-volume centres. There was no difference in six-month death or new disability between high- and low-volume ECMO centres in VV-ECMO [OR: 1.09 (0.65-1.83), p = 0.744], VA-ECMO [OR: 1.10 (0.66-1.84), p = 0.708], and ECPR-ECMO [OR: 1.38 (0.37-5.08), p = 0.629]. This finding was persistent in all sensitivity analyses, including exclusion of patients who were transferred between high- and low-volume centres.

Conclusion

There was no difference in death or disability at six months between high- and low-volume centres in Australia and New Zealand, possibly due to the current model of coordinated care that includes patient transfers and training between high- and low-volume ECMO centres in our region.

Analysis of adverse events related to extracorporeal membrane oxygenation from a nationwide database of patient-safety accidents in Japan

Although adverse events related to extracorporeal membrane oxygenation have been reported, epidemiological data on life-threatening events are insufficient to study the causes of such adverse events. Data from the Japan Council for Quality Health Care database were retrospectively analyzed. The adverse events extracted from this national database included events associated with extracorporeal membrane oxygenation reported between January 2010 and December 2021. We identified 178 adverse events related to extracorporeal membrane oxygenation. At least 41 (23%) and 47 (26%) accidents resulted in death and residual disability, respectively. The most common adverse events were cannula malposition (28%), decannulation (19%), and bleeding (15%). Among patients with cannula malposition, 38% did not undergo fluoroscopy-guided or ultrasound-guided cannulation, 54% required surgical treatment, and 18% required trans-arterial embolization. In this epidemiological study in Japan, 23% of the adverse events related to extracorporeal membrane oxygenation had fatal outcomes. Our findings suggest that a training system for cannulation techniques may be needed, and hospitals offering extracorporeal membrane oxygenation should perform emergency surgeries.

Epidemiology of ischemic stroke and hemorrhagic stroke in venoarterial extracorporeal membrane oxygenation

BACKGROUND

While venoarterial extracorporeal membrane oxygenation (V-A ECMO) provides lifesaving support for cardiopulmonary failure, complications may increase mortality, with few studies focusing on ischemic/hemorrhagic stroke. We aimed to determine the trends and associations of stroke incidence and mortality, and their risk factors, including the effects of annual case volumes of ECMO centers.

METHODS

Retrospective analysis was performed on the Extracorporeal Life Support Organization (ELSO) registry, including adult V-A ECMO patients from 534 international centers between 2012 and 2021, excluding extracorporeal cardiopulmonary resuscitation. Temporal trend analyses were performed for stroke incidence and mortality. Univariate testing, multivariable regression, and survival analysis were used to evaluate the associations of stroke, 90-day mortality, and impact of annual center volume.

RESULTS

Of 33,041 patients, 20,297 had mortality data, and 12,327 were included in the logistic regression. Between 2012 and 2021, ischemic stroke incidence increased (p < 0.0001), hemorrhagic stroke incidence remained stable, and overall 90-day mortality declined (p < 0.0001). Higher 24-h PaO2 and greater decrease between pre-ECMO PaCO2 and post-cannulation 24-h PaCO2 were associated with greater ischemic stroke incidence, while annual case volume was not. Ischemic/hemorrhagic strokes were associated with increased 90-day mortality (both p < 0.0001), while higher annual case volume was associated with lower 90-day mortality (p = 0.001). Hazard of death was highest in the first several days of V-A ECMO.

CONCLUSION

In V-A ECMO patients between 2012 and 2021, 90-day mortality decreased, while ischemic stroke incidence increased. ELSO centers with higher annual case volumes had lower mortality, but were not associated with ischemic/hemorrhagic stroke incidence. Both ischemic/hemorrhagic strokes were associated with increased mortality.

Prolonged VV ECMO: Navigating the Unchartered Sea

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

Long-Term Outcomes of Extracorporeal Life Support in Respiratory Failure

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

Waitlist Mortality and Extracorporeal Membrane Oxygenation Bridge to Lung Transplant

BACKGROUND

Use of extracorporeal membrane oxygenation (ECMO) as bridge to lung transplant has increased. However, little is known about patients placed on ECMO who die while on the waiting list. Using a national lung transplant data set, we investigated variables associated with waitlist mortality of patients bridged to lung transplant.

METHODS

All patients supported on ECMO at time of listing were identified using the United Network for Organ Sharing database. Univariable analyses were performed using bias-reduced logistic regression. Cause-specific hazard models were used to determine the effect of variables of interest on hazard of outcomes.

RESULTS

From April 2016 to December 2021, 634 patients met inclusion criteria. Of these, 445 (70%) were successfully bridged to transplant, 148 (23%) died on the waitlist, and 41 (6.5%) were removed for other reasons. Univariable analysis found associations between waitlist mortality and blood group, age, body mass index, serum creatinine, lung allocation score, days on waitlist, United Network for Organ Sharing region, and being listed at a lower-volume center. Cause-specific hazard models demonstrated that patients at high-volume centers were 24% more likely to survive to transplant and 44% less likely to die on the waitlist. Among patients who were successfully bridged to transplant, there was no difference in survival between low- and high-volume centers.

CONCLUSIONS

ECMO is an appropriate strategy to bridge selected high-risk patients to lung transplant. Of those placed on ECMO with intent to transplant, about one quarter may not survive to transplantation. High-risk patients requiring advanced support strategies may be more likely to survive to transplant when bridged at a high-volume center.

Association between Case Volumes of Extracorporeal Life Support and Clinical Outcome in Out-of-Hospital Cardiac Arrest

AIM

Extracorporeal life support (ECLS) for out-of-hospital cardiac arrest (OHCA) is increasing. There is little evidence identifying the association between hospital ECLS case volumes and outcomes in different populations receiving ECLS or conventional cardiopulmonary resuscitation (CPR). The goal of this investigation was to identify the association between ECLS case volumes and clinical outcomes of OHCA patients.

METHODS

This cross-sectional observational study used the National OHCA Registry for adult OHCA cases in Seoul, Korea between January 2015 and December 2019. If the ECLS volume during the study period was >20, the institution was defined as a high-volume ECLS center. Others were defined as low-volume ECLS centers. Outcomes were good neurologic recovery (cerebral performance category 1 or 2) and survival to discharge. We performed multivariate logistic regression and interaction analyses to assess the association between case volume and clinical outcome.

RESULTS

Of the 17,248 OHCA cases, 3,731 were transported to high-volume centers. Among the patients who underwent ECLS, those at high-volume centers had a higher neurologic recovery rate than those at low-volume centers (17.0% vs. 12.0%), and the adjusted OR for good neurologic recovery was 2.22 (95% confidence interval (CI): 1.15-4.28) in high-volume centers compared to low-volume centers. For patients who received conventional CPR, high-volume centers also showed higher survival-to-discharge rates (adjusted OR of 1.16, 95%CI: 1.01-1.34).

CONCLUSIONS

High-volume ECLS centers showed better neurological recovery in patients who underwent ECLS. High-volume centers also had better survival-to-discharge rates than low-volume centers for patients not receiving ECLS.

Effect of Hospital Volume on Outcome of Extracorporeal Membrane Oxygenation Support - Nationwide Population-Based Cohort Study in Taiwan

BACKGROUND

In modern critical care, extracorporeal membrane oxygenation (ECMO) is crucial in the management of severe respiratory and cardiac failure. Nationwide studies of the relationship between hospital volume and outcomes of ECMO use are unavailable.

METHODS AND RESULTS

Using Taiwan's National Health Insurance Research Database, we identified 11,734 adult patients who received ECMO support in 101 hospitals between January 1, 2001, and December 31, 2017. Outcomes included in-hospital mortality, 1-year mortality, and ECMO-related complications. Cox proportional hazards model, locally estimated scatterplot smoothing, and restricted cubic spline regression were used to analyze the volume-outcome relationship. The overall in-hospital mortality rate was 65.5%, and the 1-year mortality rate was 70.6% in this database. The 101 hospitals were divided into 4 groups based on annual volume. The in-hospital and 1-year mortality rates were significantly lower in the high-volume group (annual volume >40) than in the low-volume group (annual volume <10).

CONCLUSIONS

For critical care, high-volume hospitals have superior short-term and mid-term outcomes. To make the medical system equitable and reasonable, establishing a rapid and efficient nationwide referral system should be considered.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Annual hospital procedural volume and outcome in extracorporeal membrane oxygenation for respiratory failure

BACKGROUND

The hospital mortality of patients suffering from pulmonary failure requiring venovenous extracorporeal membrane oxygenation (V-V ECMO) or extracorporeal carbon dioxide removal (ECCO₂ R) is high. It is unclear whether outcome correlates with a hospital's annual procedural volume.

METHODS

Data on all V-V ECMO and ECCO₂ R cases treated from 2007 to 2019 was retrieved from the German Institute for Medical Documentation and Information. Comorbidities and outcomes were assessed by DRG, OPS, and ICD codes. The study population was divided into 5 groups depending on annual hospital V-V ECMO and ECCO₂ R volumes (<10 cases; 10-19 cases; 20-29 cases; 30-49 cases; ≥50 cases). Primary outcome was hospital mortality.

RESULTS

A total of 25,096 V-V ECMO and 3,607 ECCO₂ R cases were analyzed. V-V ECMO hospitals increased from 89 in 2007 to 214 in 2019. Hospitals handling <10 cases annually increased especially (64 in 2007 to 149 in 2019). V-V ECMO cases rose from 807 in 2007 to 2,597 in 2019. Over 50% were treated in hospitals handling ≥30 cases annually. Hospital mortality was independent of the annual hospital procedural volume (55.3%; 61.3%; 59.8%; 60.2%; 56.3%, respectively, p=0.287). We detected no differences when comparing hospitals handling <30 cases to those with ≥30 annually (p=0.659). The numbers of ECCO₂ R hospitals and cases has dropped since 2011 (287 in 2007 to 48 in 2019). No correlation between annual hospital procedural volume and hospital mortality was identified (p=0.914).

CONCLUSION

The number of hospitals treating patients requiring V-V ECMO and V-V ECMO cases rose from 2007 to 2019, while ECCO₂ R hospitals and their case numbers decreased. We detected no correlation between annual hospital V-V ECMO or ECCO₂ R volume and hospital mortality.

Effect of hospital case volume on clinical outcomes of patients requiring extracorporeal membrane oxygenation: a territory-wide longitudinal observational study

Background

The utilization of extracorporeal membrane oxygenation (ECMO) has increased rapidly around the world. Being an overall low-volume high-cost form of therapy, the effectiveness of having care delivered in segregated units across a geographical locality is debatable.

Methods

All adult extracorporeal membrane oxygenation cases admitted to public hospitals in Hong Kong between 2010 and 2019 were included. “High-volume” centers were defined as those with >20 extracorporeal membrane oxygenation cases in the respective calendar year, while “low-volume” centers were those with ≤20. Clinical outcomes of patients who received extracorporeal membrane oxygenation care in high-volume centers were compared with those in low-volume centers.

Results

A total of 911 patients received extracorporeal membrane oxygenation—297 (32.6%) veno-arterial extracorporeal membrane oxygenation, 450 (49.4%) veno-venous extracorporeal membrane oxygenation, and 164 (18.0%) extracorporeal membrane oxygenation-cardiopulmonary resuscitation. The overall hospital mortality was 456 (50.1%). The annual number of extracorporeal membrane oxygenation cases in high- and low-volume centers were 29 and 11, respectively. Management in a high-volume center was not significantly associated with hospital mortality (adjusted odds ratio (OR) 0.86, 95% confidence interval (CI): 0.61–1.21, P=0.38), or with intensive care unit mortality (adjusted OR 0.76, 95% CI: 0.54–1.06, P=0.10) compared with a low-volume center. Over the 10-year period, the overall observed mortality was similar to the Acute Physiology And Chronic Health Evaluation IV-predicted mortality, with no significant difference in the standardized mortality ratios between high- and low-volume centers (P=0.46).

Conclusions

In a territory-wide observational study, we observed that case volumes in extracorporeal membrane oxygenation centers were not associated with hospital mortality. Maintaining standards of care in low-volume centers is important and improves preparedness for surges in demand.

Human factors in ECLS - A keystone for safety and quality - A narrative review for ECLS providers

INTRODUCTION

Although the technology used for extracorporeal life support (ECLS) has improved greatly in recent years, the application of these devices to the patient is quite complex and requires extensive training of team members both individually and together. Human factors is an area that addresses the activities, contexts, environments, and tools which interact with human behavior in determining overall system performance.

HYPOTHESIS

Analyses of the cognitive behavior of ECLS teams and individual members of these teams with respect to the occurrence of human errors may identify additional opportunities to enhance safety in delivery of ECLS.

RESULTS

The aim of this article is to support health-care practitioners who perform ECLS, or who are starting an ECLS program, by establishing standards for the safe and efficient use of ECLS with a focus on human factor issues. Other key concepts include the importance of ECLS team leadership and management, as well as controlling the environment and the system to optimize patient care.

CONCLUSION

Expertise from other industries is extrapolated to improve patient safety through the application of simulation training to reduce error propagation and improve outcomes.

Outcome and Cost of Nurse-led versus Perfusionist-led Extracorporeal Membrane Oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a resource-intense modality of care whose use has grown exponentially. We examined volume and utilization trends to identify the financial break-even point that might serve to dichotomize between nurse specialist-led and perfusionist-led ECMO programs.

METHODS

Data pertaining to patients who required ECMO support between 2018 and 2019 were reviewed. ECMO staffing costs were estimated based on national trends and modelled by annual utilization and case volume. A break-even point was derived from a comparison between nurse specialist-led and perfusionist-led models. For each scenario, direct medical costs were calculated based on utilization which was in turn defined by "low" (4 days), "average" (10 days), and "high" (30 days) duration of time spent on ECMO.

RESULTS

Within the time frame, there was a total of 107 ECMO cases with a mean ECMO duration of 11 days, within the study time frame. Overall, ECMO nursing personnel costs were less than those for perfusionists ($108,000 vs $175,000). Programmatic costs were higher in the perfusionist-led versus nurse specialist-led model when annual utilization was greater than 10 cases and ECMO duration was longer than a mean of 9.7 days. There was no difference in survival between the two models.

CONCLUSIONS

Use of a perfusionist-led ECMO model may be more cost-conscious in the context of low utilization, smaller case volume and shorter ECMO duration. However, once annual case volume exceeds 10 and mean ECMO duration exceeds 10 days, the nurse specialist-led model may be more cost-conscious.

Insight into ECMO, mortality and ARDS: a nationwide analysis of 45,647 ECMO runs

Background

Extracorporeal life support (ECLS) has become an integral part of modern intensive therapy. The choice of support mode depends largely on the indication. Patients with respiratory failure are predominantly treated with a venovenous (VV) approach. We hypothesized that mortality in Germany in ECLS therapy did not differ from previously reported literature

Methods

Inpatient data from Germany from 2007 to 2018 provided by the Federal Statistical Office of Germany were analysed. The international statistical classification of diseases and related health problems codes (ICD) and process keys (OPS) for extracorporeal membrane oxygenation (ECMO) types, acute respiratory distress syndrome (ARDS) and hospital mortality were used.

Results

In total, 45,647 hospitalized patients treated with ECLS were analysed. In Germany, 231 hospitals provided ECLS therapy, with a median of 4 VV-ECMO and 9 VA-ECMO in 2018. Overall hospital mortality remained higher than predicted in comparison to the values reported in the literature. The number of VV-ECMO cases increased by 236% from 825 in 2007 to 2768 in 2018. ARDS was the main indication for VV-ECMO in only 33% of the patients in the past, but that proportion increased to 60% in 2018. VA-ECMO support is of minor importance in the treatment of ARDS in Germany. The age distribution of patients undergoing ECLS has shifted towards an older population. In 2018, the hospital mortality decreased in VV-ECMO patients and VV-ECMO patients with ARDS to 53.9% (n = 1493) and 54.4% (n = 926), respectively.

Conclusions

ARDS is a severe disease with a high mortality rate despite ECLS therapy. Although endpoints and timing of the evaluations differed from those of the CESAR and EOLIA studies and the Extracorporeal Life Support Organization (ELSO) Registry, the reported mortality in these studies was lower than in the present analysis. Further prospective analyses are necessary to evaluate outcomes in ECMO therapy at the centre volume level.

Procedural volume and outcomes in patients undergoing VA-ECMO support

Background

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used in patients with critical cardiopulmonary failure. To investigate the association between hospital VA-ECMO procedure volume and outcomes in a large, nationwide registry.

Methods

By using administrative data from the German Federal Health Monitoring System, we analyzed all VA-ECMO procedures performed in Germany from 2013 to 2016 regarding the association of procedural volumes with outcomes and complications.

Results

During the study period, 10,207 VA-ECMO procedures were performed; mean age was 61 years, 43.4% had prior CPR, and 71.2% were male patients. Acute coronary syndrome was the primary diagnosis for VA-ECMO implantation (n = 6202, 60.8%). The majority of implantations (n = 5421) were performed at hospitals in the lowest volume category (≤ 50 implantations per year).

There was a significant association between annualized volume of VA-ECMO procedures and 30-day in-hospital mortality for centers with lower vs. higher volume per year. Multivariable logistic regression showed an increased 30-day in-hospital mortality at hospitals with the lowest volume category (adjusted odds ratio 1.13, 95% confidence interval [CI] 1.01–1.27, p = 0.034).

Similarly, higher likelihood for complications was observed at hospitals with lower vs. higher annual VA-ECMO volume (adjusted odds ratio 1.46, 95% CI 1.29–1.66, p = 0.001).

Conclusions

In this analysis of more than 10,000 VA-ECMO procedures for cardiogenic shock, the majority of implantations were performed at hospitals with the lowest annual volume. Thirty-day in-hospital mortality and likelihood for complications were higher at hospitals with the lowest annual VA-ECMO volume.