Fig. 1

Study inclusion exclusion flow chart. RRT rapid response team. OHCA out-of-hospital cardiac arrest. ROSC return of spontaneous circulation. ¹Ascertained either by manual evaluation or by a statement in the electronic form that cardiac arrest had not occurred and no evidence of chest compressions was found. ²No information entered to the electronic form by the on-site medical team and therefore could not be verified. ³Ascertained by excluding events reported from the delivery room, maternity wards, or department of gynecology. ⁴Ascertained by manual review of cases reported from the ED, general surgery, operating theatre, postoperative care unit, or any location in the imaging. ⁵In case of repeat resuscitations of a single patient, only the first arrest was included. ⁶Hemoglobin measurements lower than 4 g/dL or higher than 20 g/dL