Muscle relaxation with succinylcholine or vecuronium does not alter the rate of CSF production or resistance to reabsorption of CSF in dogs.

Abstract

The open ventriculocisternal perfusion method was used to determine the rate of cerebrospinal fluid (CSF) formation (Vf) and resistance to reabsorption of CSF (Ra) in halothane-anesthetized dogs with and without succinylcholine (n = 6) and with and without vecuronium (n = 6). Both Vf and Ra during the use of either muscle relaxant were not different than Vf and Ra when no muscle relaxant was used. Succinylcholine caused muscle fasciculations and raised CSF pressure transiently (increase of 5.5 +/- 1.0 cm H2O [mean +/- SD]), while vecuronium did not. When muscle relaxants were not used, it became difficult to distinguish the effects of cardiovascular and respiratory activity on the CSF pressure waveform, and the coefficient of variability for determination of cisternal outflow rates was increased, making Ra values less reliable. It is concluded that continuous infusion of succinylcholine or vecuronium do not affect Vf or Ra. When Vf and Ra are determined by the method of ventriculocisternal perfusion, immobilization of respiratory muscles improves both the reliability of Ra values and the usefulness of the CSF pressure waveform. If a muscle relaxant is used, either succinylcholine or vecuronium would be suitable for such studies.