Best practice & research. Clinical anaesthesiology
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewNerve stimulation in regional anesthesia: theory and practice.
There is now an accumulation of extensive and varied experience with the use of electrical stimulation for verifying the close approximation of needle and nerve, and for increasing the corresponding success rate. The application of this experience has been of proven benefit in the teaching of regional anesthetic techniques, in the performing of difficult nerve blocks, and in the use of novel accesses, resulting in decreased morbidity and a reduced requirement for local anesthetic. ⋯ Sound knowledge of the anatomy of the area to be blocked, the muscle territory subsidiary to the nerve in question, the applied neurophysiology, and the pharmacology of the local anesthetic used are needed. This chapter reviews the most important aspects, from nerve anatomy and physiology, to electrical features of the needle, and devices used for the updated clinical application of nerve stimulation in the practice of plexus regional anesthesia.
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Thoracic epidural analgesia (TEA) provides optimal perioperative anaesthesia and analgesia after thoracic and major abdominal surgery and decreases postoperative morbidity and mortality, mainly by blocking sympathetic nerve fibres. Surgery leads to a stress response characterized by sympathetic arousal, altered balance of catabolic and anabolic hormones, hypermetabolism, negative protein economy, and altered carbohydrate metabolism and immune function. A threefold increase of the plasma level of norepinephrine (noradrenaline) was detected up to 24 hours after surgery. ⋯ Optimized pain control and early mobilization decrease the riskof pulmonary complications, resulting in a shortened stay in intensive care units. In combination with early enteral nutrition, TEA leads to an earlier return of gastrointestinal function. Patients treated with thoracic epidural anaesthesia and analgesia have a better health-related quality of life.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewAdvantages and disadvantages of adrenaline in regional anaesthesia.
Adrenaline has been added to local anaesthetic solutions for more than a century. The aim has been to delay the absorption of the local anaesthetic drug and to prolong and enhance its anaesthetic effect, both in peripheral and central neuraxial blockades. ⋯ The main part of this chapter will therefore focus on the advantages and disadvantages of adrenaline in epidural analgesia. However, recent knowledge about adrenaline in peripheral blockade will also be covered, together with some pharmaceutical comments on the shelf-life of local anaesthetic mixtures containing adrenaline.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewThe pharmacokinetics of ropivacaine in hepatic and renal insufficiency.
In patients with chronic end-stage liver disease, the peak plasma concentrations of ropivacaine after a single intravenous ropivacaine dose are similar to those in healthy subjects. However, patients with end-stage liver disease have about a 60% lower mean ropivacaine clearance than healthy subjects and are thus expected to have over two-fold higher steady-state ropivacaine plasma concentrations during a continuous ropivacaine infusion. ⋯ However, uraemic patients have significantly higher alpha-1-acid glycoprotein plasma concentrations than non-uraemic patients, and the peak plasma concentrations of free ropivacaine (related to toxicity) are similar in both groups. The pharmacokinetics of intravenously administered ropivacaine in patients with renal insufficiency and the possibility of clinically significant (S)-2',6'-pipecoloxylidide metabolite accumulation during continuous or repeated ropivacaine administration in these patients remain to be clarified.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewClinical pharmacology and the use of articaine for local and regional anaesthesia.
Quicker onset and shorter elimination time favours (+/-) articaine as a short-acting local anaesthetic for regional anaesthesia in day-case settings, e.g. arthroscopy (shoulder, knee), hand and foot surgery, and dentistry, because patients treated with articaine will be 'drug free' more quickly than those who receive other local anaesthetics. Articaine diffuses better through soft tissue and bone than other local anaesthetics. The concentration of articaine in the alveolus of a tooth in the upper jaw after extraction was about 100 times higher than that in systemic circulation. ⋯ Intrinsic half-lives of articainic acid are: t1/2alpha 12 minutes, and t1/2beta 64 minutes (1 hour). In dentistry, articaine is the drug of choice in the vast majority of literature. In other regional anaesthesia techniques (intravenous regional anaesthesia, epidural, spinal and plexus blocks) there are not enough data to prove that (+/-) articaine is safer and more effective than the short-acting local anaesthetics lidocaine, (+/-) prilocaine or (+/-) mepivacaine.