Prognostic scores of extracorporeal membrane oxygenation: a scoping review

doi:10.5847/wjem.j.1920-8642.2025.078

Abstract

Abstract:

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is an effective measure for saving the lives of critically ill patients. Prompt identification of the risk factors for mortality among patients receiving ECMO and comprehensive analysis of the long-term prognosis of survivors are vital. This scoping review summarized the representative prognostic scoring systems, aiming to help clinicians in selecting an appropriate scoring system to avoid unnecessary medical resource consumption and reduce ECMO-associated mortality.

METHODS: A comprehensive search of multiple databases, including PubMed, Embase, and the Cochrane Library, was conducted. After removing duplicate studies, a full-text review was performed, and all studies that reported score systems before and/or after ECMO support were included. This protocol adheres to the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and has been registered with the Open Science Framework (osf.io/zp4ge).

RESULTS: Among the 114 studies included, we identified three scores for patients receiving veno-venous ECMO (VV-ECMO), five scores for patients receiving veno-arterial ECMO (VA-ECMO), and three critical illness scores, which apply to both VV- and VA-ECMO conditions. All characteristics of these scoring systems, their advantages, and their limitations were summarized.

CONCLUSION: The implementation of an ECMO scoring system helps to assess the condition of critically ill patients, predict outcome, and provide objective indicators to determine the optimal timing for ECMO intervention. Due to the limitations of the currently available scores, further efforts in improving and validating the ECMO scoring system are needed to achieve the goals of minimizing unnecessary consumption of medical resources and reducing mortality rates.

Key words: Extracorporeal membrane oxygenation, Life support, Scoring system, Critical illness, Intensive care

Jie Zhu, Sijie Lu, Yawen Wu, Qiming Zhao, Weina Pei, Yanlin Hu, Mingming Li, Yongnan Li, Xiangyang Wu. Prognostic scores of extracorporeal membrane oxygenation: a scoping review[J]. World Journal of Emergency Medicine, 2025, 16(4): 303-312.

Figures/Tables 3

Figure 1.

Table 1.

Table 2.

Representitive venous-arterial extracorporeal membrane oxygenation (ECMO) score system

Score system	Score rubrics	Advantages	Limitations	Sample size and mortality
SAVE score^[16]	·Diagnosis ·Age ·Weight ·Pre-ECMO pulse pressure ·Pre-ECMO diastolic pressure ·Pre-ECMO cardiac arrest ·Peak inspiratory pressure ·Duration of intubation ·Acute renal failure ·Chronic renal failure ·Pre-ECMO HCO₃ level ·Other pre-ECMO organ failure	1) the first score to predict the risk of death in CS patients 2) validated predicting accuracy	1) not suitable for patient underwent cardiopulmonary resuscitation 2) not fully reflect treatment decisions made at the correct time 3) cannot eliminate the inherent uncertainty of some critically ill patients	3,846 (58%)
ENCOURAGE risk score^[21]	·Age ·Female sex ·Body mass index ·Glasgow coma score ·Creatinine ·Lactate ·Prothrombin activity	1) data incorporated from multiple sources 2) with long-term follow-up data	1) limited range of indications for scoring 2) the original data is from experienced ECMO centers, with less extensibiltiy	138 (53%)
AMI-ECMO risk Score^[23]	·Age ·Creatinine ·Serum lactate ·Lack of TIMI grade 3 blood flow in the culprit artery	A simple tool to stratify the risk of AMI-CS patients considering VA-ECMO support	Small sample size with limited statistical power and generalizability	126 (56%)
ECMO-ACCEPTS score^[25]	·Age ·Urgent admission ·Atrial fibrillation ·Hypertension ·Pulmonary hypertension ·Coronary artery disease ·Congestive heart failure ·Prior cardiopulmonary resuscitation ·Acute coronary syndrome ·Heart transplantation	A rapid bedside tool to differentiate high-risk and low-risk individuals	1) bias caused by patient baseline 2) the presence of survival bias	8,351 (39%)
REMEMBER score^[26]	·Older age ·Left main coronary artery disease ·Inotropic score ·CK-MB ·Serum creatinine ·Platelet count	Identification of patients who can benefit from VA-ECMO treatment after CABG	1) narrow applicable population 2) may underestimate the role of VA-ECMO in CABG patients	166 (55%)

Table 2.

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Score system	Score rubrics	Advantages	Limitations	Sample size and mortality
PRESERVE score^[6]	· Age · Body mass index · Immunocompromised status · SOFA score · Pre-ECMO MV duration · Prone positioning · Plateau pressure · PEEP	1) high accuracy in evaluating ARDS patients 2) fewer scoring items and convenient to use	1) indications need to be expanded 2) conservative parameter selection	140 (40%)
RESP score^[9]	· Age · Immunocompromised status · Pre-ECMO MV duration · Acute respiratory diagnosis group diagnoses · Central nervous system dysfunction · Acute non-pulmonary infection · Neuromuscular blockade agents before ECMO · Pre-ECMO nitric oxide use · Pre-ECMO bicarbonate infusion · Pre-ECMO cardiac arrest · PaCO₂ · Peak inspiratory pressure	1) sample size is large and representative 2) accurately predict prognosis	1) recalibration is needed as diseases and treatments develop 2) multiple evaluation items	2,355 (43%)
ECMOnet score^[13]	· Pre-ECMO hospital length of stay · Bilirubin · Creatinine · Hematocrit · Mean arterial pressure	1) high accuracy in evaluating patients with ARDS caused by influenza A 2) parameters are simple and easy to obtain	1) affected by patient’s comorbidities 2) needs further verification in patients with other respiratory failure	60 (32%)

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