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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Comparative Study Clinical Trial Controlled Clinical Trial
Suxamethonium-induced facilitation of spontaneous frontal EMG activity.
The behaviour of spontaneous frontal electromyographic activity (FEMG) was studied during the recovery from suxamethonium and vecuronium block. In order to obtain comparable conditions in the study groups, the duration of the suxamethonium block was prolonged with a suxamethonium infusion. The FEMG was continuously recorded and the evoked electromyographic (EEMG) and twitch tension (ETT) responses were measured every 10 s from the thenar muscles. ⋯ In the suxamethonium group there was an increase in FEMG in all six patients when EEMG had recovered to 10%, and significantly higher FEMG readings were obtained during further recovery from the block. Thus, early recovery of neuromuscular transmission is detected by FEMG more easily when suxamethonium is used instead of vecuronium. The different behaviour of FEMG may reflect a difference in the recovery ratio of ETT/EEMG or in the anaesthetic depth caused by the two types of neuromuscular blockers.