The purpose of this study is to investigate the relationship among regional transcranial oxygen saturation (rSO2), brain tissue oxygen pressure (PbtO2) and cerebral perfusion pressure (CPP) in patients with severe traumatic brain injury (TBI).

Experience with rsO2 assessed by near infrared spectroscopy (NIRS) in patients with severe TBI is lacking. Reports about the usefulness of rSO2 are contradictory as regards its technical reliability and clinical value. Continuous time-domain analysis comparing rSO2, PbtO2 and CPP has never been carried out and the correlation among these variables remains largely unknown. A significant association between rSO2 and these clinically important variables would suggest that cerebral oximetry provides relevant data signifying that rSO2 might be a useful tool assessing cerebral oxygenation in selected patients with TBI.

Inclusion Criteria:

• Severe Traumatic Brain Injury (Glasgow Coma Scale < 9)
• Having an intraparenchymal cerebral ICP/PbtO2 catheter previously inserted.
• Expected length of ICU stay > 1 days

Exclusion Criteria:

• Patient's relatives refusal to patient's inclusion in the study
• Patients necessitating ongoing resuscitation
• End-stage in which death is imminent
• Deficient signal of rSO2 impeding its proper valuation

Stable patients with severe traumatic brain injury (Glasgow Coma Scale < 9) monitored through intracranial pressure (ICP) and brain tissue partial pressure of oxygen (PbtO2) probe, inserted for indications other than inclusion in this study