Articles: nerve-block.
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Randomized Controlled Trial Clinical Trial
Intrathecal fentanyl prolongs sensory bupivacaine spinal block.
The purpose of investigation was to study the effect of intrathecal fentanyl on the onset and duration of hyperbaric bupivacaine-induced spinal block in adult male patients. Forty-three patients undergoing lower extremity or genitourinary surgery were enrolled to receive either 13.5 mg hyperbaric bupivacaine 0.75% + 0.5 ml CSF it, (Group I) or 13.5 mg hyperbaric bupivacaine 0.75% + 25 micrograms fentanyl it, (Group II) according to a randomized assessor-blind protocol. The onset and duration of sensory block were assessed by pinching the skin with forceps in the midclavicular line bilaterally every two minutes for first twenty minutes and then every five to ten minutes. ⋯ Fewer patients demanded pain relief in the fentanyl-treated group than in the control group in the early postoperative period (19% vs 59%; P < 0.05). Episodes of hypotension were more frequent in the fentanyl-treated group than in the control group (43% vs 14%; P < 0.05). We conclude that fentanyl, 25 micrograms it, prolonged the duration of bupivacaine-induced sensory block (sensory regression to L1 dermatone) by 28% and reduced the analgesic requirement in the early postoperative period following bupivacaine spinal block.
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J Bone Joint Surg Br · Nov 1995
Randomized Controlled Trial Comparative Study Clinical TrialFemoral nerve block in extracapsular femoral neck fractures.
We randomised 50 patients with extracapsular fractures of the femoral neck to receive either a bupivacaine femoral nerve block or systemic analgesia alone. A femoral nerve block was found to be an easy and effective procedure which significantly reduced perioperative analgesic requirements and postoperative morbidity.
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alpha(2)-Adrenoceptor agonists like clonidine, dexmedetomidine, and ST-91, inhibit nociceptive reflex activity predominantly by a spinal mode of action. They mimic the action of the inhibitory transmitter noradrenaline, which is released from the terminals of bulbospinal monoaminergic pathways. The inhibition by noradrenaline is due partly to hyperpolarization of the postsynaptic neuronal membrane; however, the selective antinociceptive effect of the alpha(2)-adrenoceptor agonists results from reduction of the release of the excitatory transmitters such as glutamate and substance P, blockade of the binding of substance P to spinal neurones, and enhancement of the action of the inhibitory transmitter, 5-hydroxytryptamine. ⋯ Moreover, impulse conduction in C fibres of peripheral nerves is far more reduced by these compounds than that in A fibres. Antinociceptive effects are reported to occur in various models of clinical pain, e.g. the formalin test, adjuvans-induced arthritis, autotomy following deafferentation, and "hyperalgesia" after nerve ligation. Therefore, the mechanisms involved in antinociception may also be responsible for the analgesia produced by alpha(2)-adrenoceptor agonists.
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Regional anesthesia · Nov 1995
Clinical TrialArea of paresthesia as determinant of sensory block in axillary brachial plexus block.
Paresthesia is widely considered a useful indicator for locating components of the brachial plexus using the axillary approach. While establishing axillary brachial plexus blocks, the authors attempted to correlate the area of paresthesia with the effectiveness of the sensory block. ⋯ Eliciting paresthesia at the nerve supplying the area of a planned surgical incision is a reliable determinant of successful axillary brachial plexus block.