Articles: nerve-block.
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Anesthesia and analgesia · Nov 1988
Comparative StudyComparative motor-blocking effects of bupivacaine and ropivacaine, a new amino amide local anesthetic, in the rat and dog.
Ropivacaine (S-(-)-1-propyl-2',6'-pipecoloxylidide) is a new local anesthetic that is structurally related to mepivacaine and bupivacaine. The comparative effects of ropivacaine and bupivacaine on motor function were assessed in the laboratory rat and dog. (It was not possible to accurately evaluate sensory blockade in these models.) Several concentrations of both agents were injected in the region of the sciatic nerve of the rat and into the lumbar epidural or subarachoid space in the dog. Epidural blockade was also performed utilizing solutions of ropivacaine and bupivacaine which contained epinephrine (1:200,000). ⋯ In the epidural and spinal studies in the dog, ropivacaine was less potent and had a shorter duration of motor blockade than did bupivacaine at equal drug concentrations. A 1.0% solution of ropivacaine produced epidural motor blockade similar in onset and duration to that achieved with a 0.75% solution of bupivacaine. Epinephrine did not significantly prolong the duration of motor blockade of either agent after epidural administration.
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Regional-Anaesthesie · Oct 1988
[Influence of minimum current for peripheral nerve stimulation on the latency and success rate of sciatic blockade].
The efficacy of conduction anesthesia depends to a great extent on accurate application of the local anesthetic solution (LA) in close proximity to the nerve trunk. The problem with most peripheral nerve stimulators available in the past was that they did not provide a small enough electrical stimulus. Correct positioning of the needle could not be guaranteed if muscle contractions occurred. New current-controlled stimulators have recently been developed with low currents from 0.1 mA upwards. We studied the intensity of stimulus currents eliciting just-visible muscle contractions in the lower leg (m. triceps surae) to see how this influenced the latency and success rate of sciatic nerve block. ⋯ In a randomized study, 35 patients (18-68 years, ASA I and II) undergoing elective surgery were investigated. The block was performed by posterior approach using 30 ml 1% prilocaine. The stimulator was switched on with a frequency of 1 impulse/s and a stimulus current of 1 mA when the insulated needle was at a depth of 4 cm. In group 1 (n = 5) LA was injected when the first visible muscle contractions occurred at a current of 1.0 mA, but vanished if the current was diminished. In group 2 (n = 10) the needle was placed if a minimum current of 0.5 mA just triggered a muscular response. In group 3 (n = 10) the threshold current was 0.3 mA and in group 4 (n = 10) 0.1 mA. In all cases direct contact between the needle tip and the nerve was avoided.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Am Podiatr Med Assoc · Oct 1988
Randomized Controlled Trial Comparative Study Clinical TrialDigital perfusion with tibial nerve block. A comparative study of eight local anesthetics.