Maayke Hunfeld

148 Chapter 5 Methods Setting This retrospective study was performed at the pediatric intensive care unit (PICU) of Erasmus MC Sophia Children’s Hospital in Rotterdam, providing health care to children in the southwest of The Netherlands (25% of the Dutch population). The Erasmus MC Ethical Review Board approved the study protocol (MEC-2020-0143). Patients All children from 0-17 years with OHCA between 2012 and 2017, who were subsequently admitted to our PICU and who received an early brain MRI (within 1 week post- OHCA) were eligible for inclusion. OHCA was defined as unresponsiveness with absent palpable pulse, no signs of life, or healthcare provider perceived need for chest compressions for at least one minute. Children with a pre-arrest Pediatric Performance Category (PCPC) score of > 3, traumatic OHCA or intracranial lesions such as intracranial haemorrhage, brain tumor, or meningitis as a cause of the arrest were excluded. Data collection OHCA data were retrospectively collected from the emergency vehicle registration forms and electronic health records. We collected: 1. Basic patients characteristics (e.g. gender, age, pre-arrest PCPC score, socio-economic status (SES), 2. CA characteristics (etiology, first monitored rhythm, bystander cardiopulmonary resuscitation (CPR), duration CPR, first pH and lactate. 3. post-CA characteristics. 4. Outcome (survival, PCPC at hospital discharge and 24 months after OHCA, cause of non-survival and in case of non-survival timing of decision to withdraw treatment). The SES was calculated using a ‘Status Score’ divided into tertiles to interpret a ‘low status’, middle status’ and ‘high status’. The ‘Status Score’ is based on income, education level and unemployment rate by postal code (15). Neuroimaging From 2017, children who survived the first days after OHCA underwent MR imaging studies of the brain within 7 days post-OHCA as part of our post-ROC care. Before 2017 it was at the discretion of the treating clinician and not as part of standard care.