Articles: nerve-block.
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Randomized Controlled Trial Clinical Trial
Interaction of magnesium sulphate with vecuronium-induced neuromuscular block.
We have investigated the interaction between magnesium sulphate 40 mg kg-1 i.v. and vecuronium. First, we determined the effect of pretreatment with magnesium on the potency of vecuronium using a single bolus dose-response technique. In addition, we compared the time course of vecuronium-induced neuromuscular block (vecuronium 100 micrograms kg-1) with and without magnesium pretreatment. ⋯ This was also true for the recovery index (20.1 (6.6) min vs 10.6 (3.4) min; P < 0.05) and duration to 75% recovery (63.4 (9.9) min vs 35.8 (6.9) min; P < 0.05). In the context of rapid sequence induction, pretreatment with MgSO4 improved the intubating score of vecuronium compared with vecuronium without MgSO4, reaching the same quality as that with suxamethonium 1 mg kg-1. We conclude that magnesium pretreatment increased the neuromuscular potency of vecuronium, in addition to modifying the time course of its neuromuscular block.
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We have studied the effect of renal function on the pharmacodynamics of mivacurium. Sixty patients were allocated to three groups according to creatinine clearance: group C (control), creatinine clearance > 50 ml min-1; group P (preterminal renal failure), creatinine clearance < 50 ml min-1 > 20 ml min-1; group T(terminal renal failure), creatinine clearance < 20 ml min-1. Neuromuscular transmission (train-of-four) was monitored using electromyography from the hypothenar muscle with stimulation of the ulnar nerve. ⋯ The dose of mivacurium necessary to maintain 95% neuromuscular block was similar in patients with normal renal function and patients with different levels of renal impairment. Recovery from neuromuscular block after ceasing mivacurium infusion was significantly prolonged in patients with preterminal renal impairment. There was a close correlation between mivacurium pharmacodynamics and pseudocholinesterase activity, but not creatinine clearance.
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Randomized Controlled Trial Clinical Trial
Effect of arm position on the effectiveness of perivascular axillary nerve block.
The influence of arm position on the effectiveness of perivascular axillary nerve block with a catheter was assessed prospectively in two groups of patients. Ninety patients were allocated randomly to receive 1% mepivacaine with adrenaline 40 ml with the arm either adducted or abducted. ⋯ There were no statistically significant differences in onset time, spread of analgesia, motor block or success rate between the two groups. Proximal flow of the local anaesthetic-contrast agent mixture was neither facilitated by arm adduction nor was it necessary for the development of a successful block.
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Clinical Trial
The maximum depth of an atracurium neuromuscular block antagonized by edrophonium to effect adequate recovery.
The inability of edrophonium to rapidly reverse a deep nondepolarizing neuromuscular block may be due to inadequate dosage or a ceiling effect to antagonism of neuromuscular block by edrophonium. A ceiling effect means that only a certain level of neuromuscular block could be antagonized by edrophonium. Neuromuscular block greater than this could not be completely antagonized irrespective of the dose of edrophonium administered. The purpose of this study was to determine whether a ceiling effect occurred for antagonism of an atracurium-induced neuromuscular block by edrophonium and, if so, the maximum level of block that could be antagonized by edrophonium. ⋯ There is a maximum level of neuromuscular block that can be antagonized by edrophonium to effect adequate recovery. The level corresponds approximately to the reappearance of the fourth response to TOF stimulation. It is probably safest to wait until this level of block occurs before edrophonium is given for reversal. Earlier administration will not hasten recovery.
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Percutaneous radiofrequency neurotomy has been used in the treatment of pain from the cervical zygapophysial joints, but the results have been modest and not compelling. Several factors might account for its apparent poor success rate, including inadequate patient selection, inaccurate surgical anatomy, and technical errors. In an effort to overcome these confounders, we used comparative local anesthetic blocks to preoperatively, definitively diagnose cervical zygapophysial joint pain and developed an amended operative technique based on formal anatomical studies. ⋯ After procedures at all levels, a brief period of postoperative pain was experienced by the patients and ataxia was a side effect of third occipital neurotomy. There were no cases of postoperative infection or anesthesia dolorosa. Given the high technical failure rate of third occipital neurotomy, we recommend that this procedure be abandoned until the technical problems can be overcome.(ABSTRACT TRUNCATED AT 250 WORDS)