Nursing care of the severe closed head injured patient has two primary goals: (1) the prevention of secondary brain injury associated with intracranial hypertension, and (2) the prevention of complications associated with immobility. This study examined the effects of six body position changes, performed as part of routine nursing care interventions, on the cerebrovascular status of 18 severely head injured patients. These changes included turning and positioning in bed, head rotation, range of motion exercises, and raising and lowering of the head of the bed. All subjects had baseline mean intracranial pressures of ≤ 15 mm/Hg, and cerebral perfusion pressures of ≥ 50 mm/Hg. Over 200 observations of the effects of position changes on heart rate (HR), mean arterial blood pressure (MABP), mean intracranial pressure (MICP), and cerebral perfusion pressure (CPP) were recorded and analyzed. With the exception of the intervention raising the head of the bed, all position changes produced increases in HR, MABP, MICP, and CPP. Typically, the physiologic changes were transient and showed recovery toward baseline values in oneminute postintervention measurements. The results of this study suggest that passive position changes may be performed safely upon severe closed head injured patients with baseline MICPs ≤ 15 mm/Hg, provided CPPs are maintained above 50 mm/Hg throughout each position change and provided multiple fractures do not preclude these position changes.