Articles from Regional anesthesia and pain medicine

Reg Anesth Pain Med · May 1999

Randomized Controlled Trial Clinical Trial

Quantitative sensory changes in humans after intravenous regional block with mepivacaine.

In previous studies we have demonstrated that after intravenous regional block (IVRA) with dilute mepivacaine, there is a decrease in neurogenic inflammation as well as in post-ischemic hyperemia and steady-state flow, the latter for at least 60 minutes. It is unclear whether these vascular reactions reflect a uniform depression of nerve function in the treated arms. Because the various afferents convey impulses from different types of sensory receptors, we used quantitative sensory testing (QST) to define these effects of IVRA with mepivacaine. ⋯ There was no uniform depression of nerve function after IVRA. The cold receptors and/or their Adelta-fibers were selectively depressed after the block. In conjunction with earlier findings, this suggests that IVRA with mepivacaine can differentially decrease neurogenic inflammation, with little impairment of sensory function.

Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic.

Interscalene brachial plexus block (ISB) is associated with phrenic block and diaphragmatic paralysis when high volumes (40-50 mL) of local anesthetic are injected. The goal of our study was to test if a low volume of local anesthetic administered while maintaining proximal digital pressure might more selectively block the brachial plexus and decrease the frequency of phrenic nerve block. ⋯ Decreasing the volume of local anesthetic and applying proximal digital pressure to the site of injection is not effective in reducing the cervical block spread and the frequency or intensity of diaphragmatic paralysis during interscalene ISB.

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Reg Anesth Pain Med · May 1999

Comparative Study

Preemptive intrathecal ketamine injection produces a long-lasting decrease in neuropathic pain behaviors in a rat model.

Ketamine is an N-Methyl-D-Aspartate (NMDA) receptor antagonist, which has been found to effectively treat somatic and neuropathic pain. This study examines the effect (on neuropathic pain) of preemptive ketamine using different routes of administration (intrathecal versus intraperitoneal). ⋯ Neuropathic pain behaviors were significantly reduced for at least 2 weeks after intrathecal ketamine was preemptively administered to animals undergoing surgery to induce neuropathic pain. The mechanism of action is thought to be prevention of spinal cord sensitization.