The primary outcome is brain relaxation scales , an indirect evaluation of ICP ; secondary endpoints include cerebral metabolism variables ( jugular venous oxygen saturation [ SjvO ( 2 ) ] , arterial-jugular venous differences in oxygen [ CajvO ( 2 ) ] , glucose [ A-JvGD ] , lactate [ A-JvLD ] , and cerebral extraction ratio for oxygen [ CERO ( 2 ) ] ) and fluid volumes .