Normal SjVO2 values range from 55% to 75%.3 Values less than 50% indicate relative cerebral ischemia . A decreased SjVO2 value may result from increased oxygen demand or reduced oxygen delivery, such as from a vasospasm, excessive hyperventilation, inadequate cerebral perfusion pressure (CPP), fever, or seizure. Technical issues, such as catheter kinking, dislodgment, or migration against a vessel wall, may cause SjVO2 values greater than 75% and an increased signal quality intensity reading.