Abstract

The influence of spinal anesthesia on cerebrospinal fluid (CSF) pressure oscillations was investigated in 39 adult men. Mean (±SEM) CSF pressure was increased significantly ( p < 0.01) from 19.7 ± 1.1 to 22.9 ± 1.2 mm Hg 2 minutes after the subarachnoid administration of a solution of 14 mg of tetracaine in glucose 12.5%. CSF pressure oscillations also increased significantly ( p < 0.001), the mean (±SEM) rise in amplitude being 1.5 ± 0.1 mm Hg. There was no change in blood pressure during the period of measurement (2 minutes). CSF pulse pressure oscillations remained elevated in patients in whom mean CSF pressure had returned to the preinjection level. This increase in CSF pressure oscillations could be explained by a disturbance in cerebrospinal pressure autoregulation due to the effect of the local anesthetic solution. Alterations of the pressure-volume ratios of the CSF system may also be involved.