Enflurane Causes a Prolonged and Reversible Increase in the Rate of CSF Production in the Dog

Abstract

Using the open ventriculocisternal perfusion method, rates of CSF production and reabsorption by bulk flow were examined in dogs anesthetized with either enflurane (2.2%) in N2 (60-70%) and O2, or N2O (60-70%) and enflurane (< 0.2%) in O2 (controls). The mean rate of CSF production increased significantly with enflurane (2.2%) from 0.055 .+-. 0.020 ml/min (mean) in controls to 0.082 .+-. 0.033 ml/min (n = 12). After this initial increase of .apprx. 50%, the production rate decreased significantly by .apprx. 7.4%/h. When the expired concentration of enflurane was decreased from 2.2 to < 0.2%, the mean rate of CSF production decreased to control values at 45-50 min. An intracerebral accumulation of CSF resulting from this enflurane-induced increase in CSF production may contribute in part to increased intracranial pressure when the dura is intact.