[Sedation from spinal anesthesia]

A sedative effect of spinal anaesthesia has been described but has attracted little attention in clinical practice. The present study was designed to assess the mood state of unpremedicated surgical patients under spinal anaesthesia with a quantitative self-rating method.

15 unpremedicated patients scheduled for minor operations under spinal anaesthesia were enrolled in this study. After administration of 25 mg ephedrine S.C. for stabilization of blood pressure spinal anaesthesia was induced with 20 mg hyperbaric 0.5% bupivacaine. The mood state was assessed immediately before and 20 min after induction of spinal anaesthesia with the adjective checklist (ACL) of Janke and Debus. The ACL is a method of self-assessment by acceptance or refusal of 123 adjectives.

No significant changes in heart rate and blood pressure occurred during the observation period. The main changes in mood state consisted in a increase in "desactivation" and "fatique" and in a decrease in "activation", "excitement" and in "anxiety".

In unpremedicated subjects the effect of spinal anaesthesia on mood state manifests itself mainly in sedation. This effect is most likely due to the deafferentiation with pronounced reduction of muscle afferent activity. It seems reasonable to refrain from a sedative premedication in many patients scheduled for spinal anaesthesia. If sedative drugs are given, an interaction with the non-pharmacological sedation of the deafferentiation must be taken into account.