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Chapter question: The ECPR phone has rung. Which of these patients should be cannulated — and how much does the criteria list on the wall actually know?
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Evidence search date: 11 September 2026.
Primary sources: ECPR and Resuscitative ECMO (Shinar and Badulak), Chapter 3, which reviews every eligibility component against its evidence and reproduces the Minnesota, Vancouver and Prague protocols; ELSO Red Book 6th edition Chapter 32, which reproduces the ELSO example inclusion criteria (Table 32-1); and ISCCM Manual Chapter 40.
The dominant evidence base for this chapter is SAVE-J II — a retrospective registry of 2,157 adults who received ECPR across 36 Japanese institutions between 2013 and 2018 — and its family of secondary analyses, which between them examine signs of life, pupillary findings, transient return of spontaneous circulation, initial asystole, initial pulseless electrical activity, rhythm conversion, prolonged low-flow time, sex and centre volume. All of it is observational, all of it is from patients who were selected for ECPR, and none of it tells you what would have happened to the patients who were refused.
Everything in this chapter is from structured abstracts. No full text was retrieved for any of the selection literature; the WebFetch quota was spent on Chapter 19's three anchor sources. Every row seeded from this chapter is marked Verified = No, and where two analyses disagree the disagreement is printed rather than resolved.
The ILCOR position, from the most recent systematic review of the field, is the honest starting point: "Recent randomized trials suggest potential benefit of ECPR, but the certainty of evidence remains low. It is unclear which patients might benefit from ECPR."
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| This chapter owns | Deferred to |
|---|---|
| What a selection criterion is actually for; the definitional contamination that affects every number in the field; the published criteria sets side by side; how well the ELSO example criteria discriminate; each criterion examined separately — age, witnessed status, bystander CPR, no-flow, initial rhythm, rhythm at the door, signs of life, transient ROSC, pH, lactate, end-tidal CO₂, comorbidity and aetiology; why prognosis and treatment effect point in opposite directions; the published scores and the machine-learning models; how to write a unit's criteria; and the coupling between how tight the criteria are and how good the team becomes | Why time is the indication, the sixty-minute controversy and the trials themselves → Chapter 19 |
| Cannulation during chest compressions → Chapter 21 | |
| The first hours after flow → Chapter 22 | |
| Neurological assessment and prognostication after cannulation → Chapter 23 | |
| Recognising futility, withdrawal, organ donation → Chapter 24 | |
| Prognostic scores as a general subject, including SAVE and RESCUE-IHCA → Chapter 30 | |
| Accidental hypothermia in depth → Chapter 65 | |
| Whether to offer ECPR at all, cost and equity → Chapter 77 |
A unit's ECPR criteria list looks like a clinical decision rule. It is not one. It is doing three different jobs simultaneously, and most of the arguments about ECPR eligibility are arguments between people who are each thinking about a different one.
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Physiology — the three jobs, and why they conflict
1. Prognostic selection: who is likely to survive? This is what the literature measures, and it is the only one with data. Every odds ratio in this chapter comes from asking which ECPR recipients did well.
2. Treatment-effect selection: who is likely to benefit from ECPR specifically? This is what the decision actually requires, and it is a different question. A patient who would have survived with conventional CPR gains nothing from cannulation but takes all its risk. §20.6 shows that these two questions can point in opposite directions, with quantitative evidence.
3. Operational selection: what can this team do, at this hour, without failing? A criterion that a night team cannot apply in ninety seconds is not a criterion. This job is why the list exists at all — Chapter 19 §19.1 established that the decision cannot be made well in the moment, so it must be made in advance.
The three jobs pull in different directions. Prognostic selection makes the list long. Operational selection makes it short. Treatment-effect selection would sometimes make it select the opposite patients.
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Chapter 19 set out the three randomised trials in full. For this chapter their contribution is sharply limited, and the ECPR textbook states the limitation precisely: "Clinical trials remain limited to a single inclusion criterion, and thus are only able to inform of benefits to that specific patient group rather than providing evidence for optimal eligibility criteria."
ARREST randomised only patients with refractory ventricular fibrillation. INCEPTION randomised only patients with ventricular arrhythmias. PRAGUE-OHCA randomised all rhythms and found that the non-shockable patients did badly. Between them they tell you that ECPR can work in shockable rhythms in a good system. They do not tell you where to put the age limit, what to do about an unwitnessed arrest, or whether a lactate of 15 should stop you. Every one of those decisions rests on observational data.
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Danger — the shape of the evidence base, and what it structurally cannot show
Almost everything that follows comes from cohorts of patients who were selected for ECPR. That has two consequences that no amount of statistical adjustment removes.
First, the comparison group is missing. When a study reports that patients with signs of life did better, it is comparing ECPR recipients with signs of life against ECPR recipients without them. It is not comparing them against patients who had signs of life and did not get ECPR — those patients are usually not in the dataset at all.
Second, every criterion already in use is invisible. If a registry's contributing units all excluded patients over 75, the registry cannot tell you anything about patients over 75. Selection criteria are self-confirming: they remove the evidence that would refute them.
The practical consequence: treat every finding in §20.5 as describing who does well among those cannulated, which is a prognostic statement, and not who should be cannulated, which is a treatment-effect statement. §20.6 is where the difference becomes quantitative.
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Before any criterion can be weighed, two definitional problems have to be stated, because they contaminate the numbers rather than merely qualifying them.
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Pitfall — ECPR and post-ROSC ECMO are being counted together
The ECPR textbook flags it plainly: "Many studies have been ambiguous in regard to differentiating cases initiated during active chest compressions versus those commenced after ROSC. The latter represents a better prognosis and should not be classified as 'ECPR'."
A patient cannulated during compressions and a patient cannulated after a pulse returned are in different diseases with different prior probabilities, and some published ECPR series contain both. Every survival figure in this chapter is therefore an upper bound of uncertain tightness.
When reading any ECPR paper, find the sentence that says whether the circuit was started with or without a pulse. If it is not there, the survival figure is not comparable with one where it is.
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The second problem is the one Chapter 19 §19.1 opened with: "refractory" has no agreed definition, with published thresholds ranging from 10 to 60 minutes. A unit that defines refractory as 10 minutes and a unit that defines it as 30 are selecting different patients before they apply a single other criterion, and their published survival figures are not comparable.
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Clinical pearl — the two questions to ask of any ECPR outcome figure before you use it
A 40% survival figure from a programme that cannulates at 15 minutes, some of them after ROSC, and a 20% figure from a programme that cannulates at 45 minutes strictly during compressions, may describe identical clinical skill. Benchmark against a programme whose definitions match your own, or do not benchmark.
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