Articles: nerve-block.
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Rev Esp Anestesiol Reanim · Dec 2006
Randomized Controlled Trial Comparative Study[Femoral nerve block for postoperative analgesia after anterior cruciate ligament reconstruction: comparison of 2 concentrations of bupivacaine with clonidine in 3 modes of administration].
The continuous femoral nerve block is used for postoperative orthopedic analgesia. ⋯ A continuous femoral nerve block is useful for managing pain after anterior cruciate ligament surgery. The application of 5 mL x h(-1) in continuous infusion or in PCA system bolus doses provides excellent postoperative analgesia. Use of 0.0625% bupivacaine decreases overall consumption of analgesic and is not detrimental to quality of analgesia.
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IEEE Trans Biomed Eng · Dec 2006
Mechanism of nerve conduction block induced by high-frequency biphasic electrical currents.
The mechanisms of nerve conduction block induced by high-frequency biphasic electrical currents were investigated using a lumped circuit model of the myelinated axon based on Frankenhaeuser-Huxley (FH) model or Chiu-Ritchie-Rogart-Stagg-Sweeney (CRRSS) model. The FH model revealed that the constant activation of potassium channels at the node under the block electrode, rather than inactivation of sodium channels, is the likely mechanism underlying conduction block of myelinated axons induced by high-frequency biphasic stimulation. However, the CRRSS model revealed a different blocking mechanism where the complete inactivation of sodium channels at the nodes next to the block electrode caused the nerve conduction block. ⋯ This frequency difference indicated that the constant activation of potassium channels might be the underlying mechanism of conduction block observed in animal experiments. Using the FH model, this study also showed that the axons could recover from conduction block within 1 ms after termination of the blocking stimulation, which also agrees very well with the animal experiments where nerve block could be reversed immediately once the blocking stimulation was removed. This simulation study, which revealed two possible mechanisms of nerve conduction block in myelinated axons induced by high-frequency biphasic stimulation, can guide future animal experiments as well as optimize stimulation waveforms for electrical nerve block in clinical applications.
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Retropharyngeal hematoma (RPH) is rare; however, it causes airway obstruction and can be fatal. Stellate ganglion block (SGB) can cause RPH. The authors analyzed reports of patients with RPH after SGB to clarify the initial symptoms and signs, and the urgency of airway management. ⋯ RPH after SGB necessitates emergency airway management. Because airway obstruction cannot be predicted by the initial symptoms or signs, emergency airway management tools should be at hand, and the patency of the airway should be continuously evaluated after onset of RPH after SGB.
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Rev Bras Anestesiol · Dec 2006
[Postoperative analgesia for orthopedic surgeries of the hip and femur: a comparison between psoas compartment and inguinal paravascular blocks.].
This study evaluated the efficacy of a single injection of 0.25% bupivacaine in the psoas compartment or inguinal paravascular for postoperative analgesia in patients undergoing orthopedic surgeries using a peripheral nerve stimulator. ⋯ Psoas compartment block and inguinal paravascular block are excellent techniques for postoperative analgesia in orthopedic surgeries, decreasing the need for opioids. This study showed that the injection in the psoas compartment was easier and more effective in blocking the five nerves of the lumbar plexus.
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To evaluate the efficacy of nerve stimulation as an adjunct to ultrasound-guided supraclavicular nerve blocks. ⋯ For adequately imaged ultrasound-guided supraclavicular nerve blocks, a positive motor response to nerve stimulation does not increase the success rate of the block. In addition, the high false-negative rate suggests that these blocks are usually effective, even in the absence of a motor response. Nerve stimulation as an adjunct to ultrasound guidance may have a limited role.