Articles: nerve-block.
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The purpose of this study was to determine the pharmacokinetic properties of the local anaesthetic ropivacaine used with or without epinephrine for brachial plexus block. Seventeen ASA physical status I or II adult patients undergoing elective orthopaedic surgery received a single injection of 33 ml ropivacaine for subclavian perivascular block and 5 ml to block the intercostobrachial nerve in the axilla. One group (n = 8) received 0.5 per cent ropivacaine without epinephrine (190 mg) and the other (n = 9) received 0.5 per cent ropivacaine with epinephrine 1:200,000 (190 mg). ⋯ The terminal phase of the individual plasma concentration-time curves showed a varying and sometimes slow decline possibly indicating a sustained systemic uptake of ropivacaine from the brachial plexus. No central nervous system or cardiovascular symptoms attributed to systemic plasma concentrations of the drug were observed, with the dose (1.90-3.28 mg.kg-1) of ropivacaine used. It is concluded that the addition of epinephrine does not alter the pharmacokinetic properties of ropivacaine when used for subclavian perivascular brachial plexus block.
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Regional-Anaesthesie · Nov 1990
[The blood level and a pharmacokinetic model of prilocaine during a continuous brachial plexus blockade].
Continuous brachial plexus blockade achieved by repeated injections through an axillary catheter is used increasingly often for microsurgical procedures and for postoperative pain relief. Repetitive administration, especially of long-acting agents, can cause problems with local anesthetic toxicity. Based upon a pharmacokinetic analysis of prilocaine serum concentrations after single-dose axillary plexus blockade in 14 patients, a pharmacokinetic model was established from which to predict serum concentrations after successive doses. ⋯ Methemoglobinemia resulting from metabolites of prilocaine did not lead to complications in our study. It may, however, be a problem with repetitive dosages. Further investigations concerning this question would be useful.
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Fracture of the scapular is uncommon but painful. A case is described in which a comminuted scapular fracture was treated with a continuous suprascapular nerve block. With the patient lying supine an epidural needle was directed towards the scapular notch via a superior approach and an epidural catheter was placed when the notch was believed to have been identified. ⋯ Injection of 10 ml radio-opaque dye demonstrated the catheter to be lateral to the scapular notch. However, dye dispersed throughout the supraspinous fossa including the scapular notch thus blocking the suprascapular nerve. This case demonstrates that continuous suprascapular nerve block can be performed for five days and that location of the scapular notch is less important than previously thought.
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A new local anaesthetic, ropivacaine hydrochloride, was used in a concentration of 0.5 per cent in 32 patients receiving a subclavian perivascular block for upper extremity surgery. One group (n = 15) received 0.5 per cent ropivacaine without epinephrine and a second group (n = 17) received 0.5 per cent ropivacaine with epinephrine in a concentration of 1:200,000. Anaesthesia was achieved in 87 per cent of the patients in both groups in all of the C5 through T1 brachial plexus dermatomes. ⋯ The duration of sensory block was reduced by epinephrine at T1 for analgesia and at C7, C8, and T1 for anaesthesia. The duration of sensory block in the remaining brachial plexus dermatomes as well as the duration of motor block was not effected by epinephrine. There was no evidence of cardiovascular or central nervous system toxicity in either group with a mean dose of 2.5-2.6 mg.kg-1 ropivacaine.