Therapy of patients with head injuries: Key parameters for management

Background: Secondary brain injury, presumed secondary to ischemia, increases the mortality and morbidity of traumatic brain injury. Although many mechanisms appear to be involved, many potential ischemic insults result from changes in readily observable physiologic variables. Methods: A focused search of scientific articles published in English to determine what data are available to suggest parameters within which key physiologic variables should be maintained. Results: Few data demonstrate that maintenance of variables within specific ranges alters outcome; however, considerable evidence establishes associations with poor outcome and hypotension, intracranial hypertension, and cerebral venous saturation. Key parameters vary somewhat based upon the phase of treatment after injury. Other variables, such as systemic oxygen delivery and brain saturation measured by near-infrared spectroscopy, are less well linked to outcome. Conclusions: Further research is necessary to establish that manipulation of physiologic variables to maintain them within preset ranges improves outcome.