Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
-
J. Cereb. Blood Flow Metab. · Oct 1988
Reduction of cerebrospinal fluid pressure by hypocapnia: changes in cerebral blood volume, cerebrospinal fluid volume and brain tissue water and electrolytes. II. Effects of anesthetics.
Part I of these studies (Artru, 1987) examined how cerebral blood volume (CBV), CSF volume, and brain tissue water and electrolytes determined CSF pressure during 4 h of hypocapnia in sedated dogs. The three groups reported were: hypocapnia (PaCO2 20 mm Hg) with no intracranial mass (group 1), intracranial mass (epidural balloon, CSF pressure 35 cm H2O) but no hypocapnia (group 2), and intracranial mass with hypocapnia used to lower CSF pressure (group 3). It was found that in dogs with an intracranial mass (group 3) the CSF pressure-lowering effect of hypocapnia was sustained for 4 h due to improved reabsorption of CSF, decrease of CSF volume to offset reexpansion of CBV and no increase in the sum of CSF volume and CBV. ⋯ With halothane the intracranial volume increase was comprised chiefly of cerebral blood and with enflurane the intracranial volume increase was comprised chiefly of CSF. When isoflurane, fentanyl, or thiopental were used for anesthesia, the CSF pressure-lowering effect of hypocapnia was sustained. Ra did not increase and the sum of CBV and CSF volume remained reduced.