Data will be collected as a retrospective and prospective chart review from the electronic medical record of patients that were treated in the pediatric emergency department of Arkansas Children's Hospital from 10-1-13 who require medical (possible strokes, diabetic ketoacidosis, increased intracranial pressure, altered mental status, sepsis, drowning, shock, rapid sequence intubations, seizures, altered mental status, strokes, possible shunt malfunctions) or trauma (non-accidental trauma, Level One or Two Trauma with altered mental status, traumatic brain injury, altered mental status with trauma history, vascular compromise) resuscitation efforts. This study will be based on the patient information recorded in these records, such as age, medications delivered, vital signs, interventions and outcomes and compared to their PED NIRS cerebral tissue oxygenation rSO2 data. All study subject materials will be assigned a unique identifying code or number. The cerebral NIRS rSO2 data will be collected/graphed and de-identified.