[Evaluation of cerebral blood flow in severe brain injuries by SVO2 measurement in the internal jugular vein].

The purpose of the present study was to assess the value of jugular oxyhemoglobin saturation percent (SvO2) in predicting cerebral blood flow (CBF). SvO2 and CBF were measured in 25 adults with acute brain trauma (Glasgow Coma Scale < 8). From the data a classification of CBS and SvO2 was developed: in the first group of patients the presence of cerebral ischemia could be identified in the presence of low CBF (< 40 ml/min/100g) and a low SvO2. In the second group he CBF is closely coupled to and regulated by the cerebral metabolic rate of oxygen (CMRO2) and values of SvO2 are intermediate. In the third group hyperaemia was defined as both an increase of SvO2 and CBF (> 60ml/min/100g) and a decrease of CMRO2. The SvO2 was measured in 18 of these 25 patients following 1) intravenous infusion of mannitol (1 g.kg-1) and hyperventilation (PCO2 = 3.4 kPa). The data suggest that there is no correlation between SvO2 and CBF, but a reliable estimates of CBF may be made from SvO2 measurement after mannitol and hyperventilation.