Table 1 Inclusion and exclusion criteria for Sub30 study [25]

Presumed cardiac aetiology of arrest

Visibly < 18 or > 65 years old

Witnessed OHCA

Known or visible advanced pregnancy (when resuscitative hysterectomy should be performed)

Received bystander chest compressions within 3 min

No signs of life (physical movement or breathing) AND

Evidence of ineffective chest compressions suggested by the following:

• The absence of electrical activity at 20 min time-out

• End-tidal carbon dioxide level of < 1.3 kPa (10 mmHg)

Remain in cardiac arrest at 20 min following the call to emergency services OR fail to sustain ROSC in the pre-hospital setting

ECMO unlikely to benefit patient (e.g. advanced malignancy, severe frailty)