Major changes are becoming apparent among neuroanesthesists and neuros
urgeons in their attitude towards hypocarbia, blood volume, mean arter
ial pressure (MAP), cerebral perfusion pressure (CPP), anesthetic tech
nique, and brain retraction pressure. These changes are related to the
transfer from intensive care units to operating theaters of major new
physiologic data regarding oxygen delivery to tissues (DO2) and oxyge
n comsumption by tissues (VO2). These fundamental data have progressiv
ely, during the last five years, led to the concept of brain homeostas
is based on four fundamental therapeutic principles: 1) The use of mod
erate hypocarbia (as opposed to deep hypocarbia which should stay exce
ptional). 2 The use of a normal mean arterial pressure (MAP) and thus
cerebral perfusion pressure (CPP) by promoting a. - normovolemia, b. -
a hematocrit around 30 % and c. - a light anesthesia technique allowi
ng rapid recovery 3) The use of appropriate cristalloids (NaCl 0,9 % r
ather than Ringer-Lactate, and no DW5) taking into account measured os
molality. 4) The Optimisation of brain relaxation by combining an appr
opriate anesthetic technique, mannitol, head up (and head straight) po
sition, together with a lumbar drainage.