Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jul 1999
In vivo diffusion-weighted magnetic resonance microscopy of rat spinal cord: effect of ischemia and intrathecal hyperbaric 5% lidocaine.
Pathophysiologic mechanisms underlying persistent neurologic deficits after continuous spinal anesthesia using hyperbaric 5% lidocaine are still not well understood. It has been suggested that high-dose intrathecal lidocaine induces irreversible conduction block and even ischemia in white matter tracts by breakdown of the blood-nerve barrier. In this study, we use diffusion-weighted magnetic resonance microscopy to characterize the effect of intrathecal hyperbaric 5% lidocaine in rat spinal cord. The parameter measured with DWM, is an "apparent diffusion coefficient," (ADC), which can be used to exclude the presence of ischemia. ⋯ Ischemia reduced the ADC in both spinal cord white and gray matter. Hyperbaric 5% lidocaine did not affect the spinal cord ADC during the first 1.5 hours. We suggest that 5% hyperbaric lidocaine does not induce irreversible neurologic deficits by causing spinal cord ischemia.
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Reg Anesth Pain Med · May 1999
Randomized Controlled Trial Comparative Study Clinical TrialPreoperative intra-articular morphine and bupivacaine for pain control after outpatient arthroscopic anterior cruciate ligament reconstruction.
The purpose of this study was to determine whether intra-articular injection of bupivacaine, morphine, or a combination prior to surgery provided pain control after arthroscopic anterior cruciate ligament (ACL) reconstruction. ⋯ Presurgical injection of a solution of 0.25 % bupivacaine, morphine, and epinephrine provided pain control and decreased opioid use in the PACU. Increasing the morphine dose did not improve the clinical result.
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Reg Anesth Pain Med · May 1999
Randomized Controlled Trial Clinical TrialFrequency of hypotension during conventional or asymmetric hyperbaric spinal block.
The purpose of this randomized, double-blind study was to evaluate if use of an asymmetric spinal block affects the incidence of hypotension during spinal anesthesia. ⋯ Achieving an asymmetric distribution of spinal block by injecting a small dose of 0.5% hyperbaric bupivacaine through a Whitacre spinal needle into patients placed in the lateral position for 15 min reduces the incidence of hypotension during spinal anesthesia.
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Reg Anesth Pain Med · May 1999
Comparative StudyPreemptive 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.