Articles: nerve-block.
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Minerva anestesiologica · Jan 2000
Randomized Controlled Trial Comparative Study Clinical TrialInterscalene brachial plexus anesthesia with either 0.5% ropivacaine or 0.5% bupivacaine.
To compare intra- and postoperative clinical properties of interscalene brachial plexus block performed with either 0.5% ropivacaine or 0.5% bupivacaine. ⋯ This study confirmed that 0.5% ropivacaine has clinical properties similar to those of 0.5% bupivacaine, when used for interscalene brachial plexus block, providing similarly long duration in postoperative pain relief. Compared with bupivacaine, ropivacaine has the further advantage of a lower potential for central nervous system and cardiovascular toxicity.
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Anesthesia and analgesia · Jan 2000
Clinical TrialMagnetic resonance imaging of the distribution of local anesthetic during the three-in-one block.
The three-in-one technique of simultaneously blocking the femoral, the lateral femoral cutaneous (LFC), and the obturator nerves by a single injection of a local anesthetic was first described in 1973, and it was suggested that the underlying mechanism was one of cephalad spread resulting in a blockade of the lumbar plexus. Today, the technique is widely used in surgery and pain management of the lower limb. Many investigators have, however, reported suboptimal analgesia levels, particularly in the obturator nerve. The purpose of this prospective study was to trace the distribution of a local anesthetic during a three-in-one block by means of magnetic resonance imaging (MRI). Seven patients scheduled for surgery of the lower limb were analyzed with the aid of a primary MRI and then received three-in-one blocks using 30 mL of bupivacaine 0.5% under the guidance of a nerve stimulator. A secondary MRI was performed to determine the distribution pattern of the local anesthetic. It emerged that the local anesthetic blocks the femoral nerve directly, the LFC nerve through lateral spread, and the anterior branch of the obturator nerve by slightly spreading in a medial direction. No involvement of the proximal and posterior portions of the obturator nerve was observed, nor was there any cephalad spread that could have resulted in a lumbar plexus blockade. We therefore conclude that the basis of the three-in-one block is confined to lateral, medial, and caudal spread of the local anesthetic, which effectively blocks the femoral and LFC nerves, as well as the distal anterior branch of the obturator nerve. ⋯ We demonstrate by using magnetic resonance imaging that the mechanism of a three-in-one block is one of lateral, caudal, and slight medial spread of a local anesthetic with subsequent blockade of the femoral, the lateral femoral cutaneous, and the anterior branch of the obturator nerves. It does not involve cephalad spread of the local anesthetic with blockade of the lumbar plexus.
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Foot and ankle operations are being performed with greater frequency as outpatient procedures. Although the surgical procedure remains the same whether the operation is done in an inpatient or an outpatient setting, the anesthesia and postoperative analgesia are greatly affected when patients must be discharged soon after their operation. ⋯ This was the sole anesthetic technique for both the operation and the immediate postoperative period. This technique appears to have several advantages: 1) Excellent anesthesia during the operation and for about ten hours postoperatively; 2) Use of a proximal calf tourniquet, and 3) Absence of systemic or local complications as might be seen with general, spinal or epidural anesthesia.
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Antidromically propagated action potentials can be recorded in the proximal end of the severed medial articular nerve (MAN) on mechanical stimulation of an inflamed knee in rats and are referred to as dorsal root reflex (DRR) activity. The absence of DRR activity in normal rats suggests that the activity could be the result of hyperexcitability of spinal neurons induced by inflammation. In this study, the role of spinal type 1 metabotropic glutamate (mGlu(1)) receptors in the generation of DRR activity in the MAN during acute knee inflammation was investigated. ⋯ AIDA and LY39053 had no effect on recordings in the MAN from noninflamed control animals. However, spinal administration of AIDA did suppress DRR activity generated by infusion of 4-aminopyridine (4-AP), a K(+) channel blocker, into the dorsal horn of noninflamed animals. These observations suggest that mGlu(1) receptors support the generation of DRR activity in the MAN following sensitization of spinal cord neurons.
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Reg Anesth Pain Med · Jan 2000
Randomized Controlled Trial Clinical TrialEvaluation of efficacy and plasma concentrations of ropivacaine in continuous axillary brachial plexus block: high dose for surgical anesthesia and low dose for postoperative analgesia.
Ropivacaine is a potent local anesthetic that, experimentally at low concentrations, produces an effective block of pain conducting nerve fibers. Therefore, it was hypothesized that 0.1% and 0.2% ropivacaine would provide clinically adequate postoperative analgesia in continuous axillary plexus block. ⋯ Ropivacaine is safe and effective for axillary brachial plexus block. The continuous infusion of 0.1% or 0.2% ropivacaine was no more beneficial than an infusion of saline in relieving postoperative pain in patients having elective hand surgery. None of the infusions were sufficient to adequately treat the patients' pain without the addition of adjunct agents.