Articles: anesthetics.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of extradural ropivacaine and bupivacaine.
Ropivacaine, a new long acting amide type local anaesthetic, was compared with bupivacaine in a randomized double-blind study. One hundred and ten patients undergoing extradural anaesthesia received a test dose of 3 ml of 1% lignocaine with adrenaline which was followed by 15 ml of one of five solutions: 0.5, 0.75 or 1.0% ropivacaine or 0.5 or 0.75% bupivacaine. There was little difference between the groups with respect to speed of onset or sensory block. ⋯ Increasing concentration of both drugs resulted in greater degree and longer duration of motor block. Ropivacaine produced a slower onset, shorter duration and less intense motor block than the same concentration of bupivacaine. The cardiovascular changes were similar in all groups.
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Comparative Study
[Physical and pharmacokinetic properties of anesthetics and sedatives used in neuroanesthesia and resuscitation].
Pharmacokinetics of anesthetic drugs are widely influenced by their physical properties. Lipo-solubility is the most important characteristic. ⋯ The concept of effective compartment allows a best understanding of relationship between concentration, intensity and duration of action of anesthetic drugs. Constant intravenous infusion route of anesthetic drugs administration requires to be discussed.
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Anaesthesiol Reanim · Jan 1991
ReviewPain control with intrathecally and peridurally administered opioids and other drugs.
Sharp pain is conducted rapidly by myelinated delta A fibers and diffused pain slowly by nonmyelinated C fibers to pseudobipolar neurons in the posterior ganglion and from there to neurons located in the posterolateral horn of the spinal cord. From here on nociferous impulses are transmitted by excitatory peptides (e.g. substance P) or amino acids (e.g. glutamate, aspartate) through interconnecting neurons of the pain pathways, primarily on the contralateral side, to the brain stem and from there to the sensory cortex, where they are appreciated and acted upon. There are specific inhibitory receptors located on axon terminals, near to the release sites of the excitatory amino acids and peptides. ⋯ Several different approaches are being investigated for the production of selective spinal analgesia without side effects. They include: a. the use of more lipophilic, long-lasting opioids (e.g. lofentanil) which would be almost completely absorbed by the spinal cord and therefore would not reach the medullary centers; b. the development of opioids with specific affinity to kappa- and for delta- and little or no affinity to mu-receptors, primarily responsible for side effects; and c. combining lower doses of opioid agonists with alpha 2-adrenergic agonists (e.g. clonidine) or with somatostatin. It is conceivable that in the not-too-distant future, it will be possible to achieve through these measures, selective spinal analgesia without side effects.