What does the evidence say on outcomes and in-hospital mortality of Corona Virus Disease 2019 (COVID-19) patients receiving extracorporeal membrane oxygenation (ECMO) ?

What does the evidence say on outcomes and in-hospital mortality of Corona Virus Disease 2019 (COVID-19) patients receiving extracorporeal membrane oxygenation (ECMO) ?

Comment by InpharmD Researcher

Definitive conclusions as to whether ECMO should be used in patients with COVID-19 and severe respiratory failure cannot be drawn. ECMO may be considered for use in refractory COVID-19-related respiratory failure.

Background

The National Institute of Health COVID-19 Treatment Guidelines state that there is insufficient data to recommend either for or against routine use of ECMO for patients with refractory hypoxemia. [1]

The Infectious Diseases Society of America does not mention ECMO in their COVID-19 treatment guidelines. [2]

A review article assessing the provision of ECMO services outlines an action plan, detailing special centers to provide ECMO, specific personnel training involved in the ECMO processes, and infection control measures to apply before and after ECMO initiation. [3]

A review summarizing the evidence on ECMO for management of severe acute respiratory distress syndrome (ARDS) during COVID-19 states that veno-venous extracorporeal membrane oxygenation (V-V ECMO) may serve as a rescue therapy for refractory respiratory failure in the setting of acute respiratory compromise induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). [4]

A review assessing the use of ECMO in past respiratory virus outbreaks and its potential role in COVID-19 states it may be considered in patients who develop severe cardiopulmonary failure due to COVID-19 refractory to mechanical ventilation and other medical therapies. Initial reports suggest it has been used in approximately 3% of severe cases with restoration of adequate oxygenation. It was concluded that although ECMO has a role in critically ill patients, there is currently inadequate data to determine the efficacy, optimal patient selection and management of ECMO services. [5]

A review assessing the role of ECMO as a rescue therapy in COVID-19 patients states that ECMO should be reserved for critically ill patients. There may be scope for the use of ECMO as rescue therapy and it should be strongly considered in patients with severe lung injury secondary to COVID‐19.[6]

An article reviewing the existing literature on the role of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in the treatment of coronavirus-related cardiovascular collapse concluded that respiratory and mechanical circulatory support can be considered in extreme circumstances. It is recommended to reserve VA-ECMO for highly selected cases of COVID-19 in refractory cardiogenic shock with echocardiographic evidence of reduced biventricular function. [7]

Literature Review

A search of the published medical literature revealed 1 study investigating the researchable question:

What does the evidence say on outcomes and in-hospital mortality of Corona Virus Disease 2019 (COVID-19) patients receiving extracorporeal membrane oxygenation (ECMO) ?

Please see Table 1 for your response.

Study Name

Extracorporeal membrane oxygenation support in COVID-19: an international cohort study of the Extracorporeal Life Support Organization registry

Design

International, cohort study

Objective

To use the Extracorporeal Life Support Organization (ELSO) Registry to report the epidemiology, treatment, outcomes, and hospital characteristics of patients receiving ECMO with a confirmed diagnosis of COVID-19.

To examine whether patient factors and historical hospital ECMO case volume were associated with in-hospital mortality

Methods

Data from the ELSO Registry was used to characterize the epidemiology, hospital course, and outcomes of patients on ECMO support. Eligibility included being 16 years or older, and a confirmed diagnosis of COVID-19 via laboratory testing. The study spanned 213 hospitals in 36 countries.

Apart from primary findings, additional results were reported for a subset of patients meeting two criteria:

(1) classified by the ELSO data manager as having ARDS

(2) initial mode of ECMO support was venovenous ECMO

Study Groups/Patients

Full cohort:

n=1035

ARDS cohort:

n= 779

Duration

January to August, 2020

Outcome Measures

The primary outcome was in-hospital death in a time-to event analysis assessed at 90 days after ECMO initiation.

A patient being discharged alive to home or to an acute rehabilitation center, discharged to a long-term acute care center or unspecified location, or discharged to another hospital were treated as distinct competing events for the primary outcome of in-hospital mortality. Proportion of in-hospital deaths in patients who reached a final disposition of death or discharge from the hospital was also reported.

Results

Characteristics of patients at baseline:

Median age	49 years
Median body-mass index	31 kg/m2
Men	764
Pre-ECMO comorbidity (total = 1035)
ARDS	819
Acute kidney injury	301
Acute heart failure	50
Myocarditis	22

Primary Outcome:

	Full cohort n= 1035	ARDS cohort n= 779
Patient status at study completion:
Discharged alive to home or acute rehabilitation center	311 (30%)	262 (34%)
Discharged alive to long-term acute care center or unspecified location	101 (10%)	79 (10%)
Discharged to another hospital	176 (17%)	92 (12%)
Remain in the hospital (discharged from ICU)	11 (1%)	10 (1%)
Remain in the ICU	56 (5%)	40 (5%)
In-hospital death	380 (37%)	291 (37%)

The estimated cumulative incidence of in-hospital mortality 90 days after the initiation of ECMO was 37.4% (95% CI 34.4–40.4).

Mortality was 39% (380 of 968) in patients with a final disposition of death or hospital discharge.

In the subset of patients with COVID-19 receiving respiratory (venovenous) ECMO and characterized as having acute respiratory distress syndrome, the estimated cumulative incidence of in-hospital mortality 90 days after the initiation of ECMO was 38.0% (95% CI 34.6–41.5).

	Full cohort n= 983	ARDS cohort n= 738
Complications:
Seizure	6 (0.6%)	5 (0.7%)
Central nervous system (CNS) infarct	7 (0.7%)	5 (0.7%)
CNS hemorrhage	56 (6%)	44 (6%)
Hemolysis	48 (5%)	37 (5%)
Membrane lung failure	82 (8%)	63 (9%)
Pump failure	8 (0.8%)	6 (0.8%)
Circuit change	148 (15%)	99 (13%)

Study Author Conclusions

In patients with COVID-19 who received ECMO, both estimated mortality 90 days after ECMO and mortality in those with a final disposition of death or discharge were less than 40%. Results are consistent with previously reported survival rates in acute hypoxemic respiratory failure, supporting current recommendations that centers experienced in ECMO should consider its use in refractory COVID-19-related respiratory failure.

InpharmD Researcher Critique

The ELSO Registry did not externally validate the submitted data. Additionally, the final outcome of 90 days after ECMO initiation is unknown for patients who were discharged home or to an acute rehabilitation center, discharged to a long-term acute center or unspecified location, and discharged to another hospital. Furthermore, the study was not randomized or controlled – thus, definitive conclusions as to whether ECMO should be used in patients with COVID-19 and severe respiratory failure cannot be drawn.

References:

Barbaro RP. Extracorporeal membrane oxygenation support in COVID-19: an international cohort study of the Extracorporeal Life Support Organization registry. The Lancet. September 20AD. doi:https://doi.org/10.1016/S0140-6736(20)32008-0