Articles: nerve-block.
-
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.
-
A reliable, safe approach to achieving unilateral anesthesia in multiple contiguous thoracic dermatomes would be of great benefit to anesthesiologists in the acute and chronic pain setting. The multidermatomal intercostal technique is one such approach, although the anatomical mechanism of this nerve block is a matter of debate. At our pain clinic, we have used another technique, a modification of the paravertebral block, to achieve multiple segments of unilateral sensory blockade. ⋯ In order to clarify the mechanism of bilateral blockade resulting from a unilateral technique, we injected four fresh cadavers with colored latex solution using the paravertebral-peridural approach. This revealed spread of the latex across the midline prevertebrally to the contralateral paravertebral space. We conclude that the paravertebral-peridural thoracic block is a reliable, safe technique for achieving unilateral anesthesia over multiple dermatomes with a single injection.
-
Regional anesthesia · Sep 1990
Clinical Trial Controlled Clinical TrialAlkalinization of mepivacaine accelerates onset of interscalene block for shoulder surgery.
Reports evaluating the effect of alkalinization of mepivacaine on the onset of regional anesthesia have been controversial. The effect of alkalinization of mepivacaine on the onset of interscalene block has not been reported and is the subject of this study. Forty patients received an interscalene block by elicitation of paresthesia with 25-gauge, blunt level needle. ⋯ The duration of block for each observation was determined. The onset was significantly faster for all tested modalities in the pH-adjusted group. No statistically significant differences in the duration of either motor or sensory were found between the study and control groups.
-
Regional anesthesia · Sep 1990
Plasma concentrations after high doses of mepivacaine with epinephrine in the combined psoas compartment/sciatic nerve block.
A combination of psoas compartment block and sciatic nerve block was performed with a total dose of 731.5 mg mepivacaine (55 ml, 1.33%) with epinephrine (1:600,000) in patients scheduled for orthopedic surgery on one leg. In 20 patients, arterial blood samples were collected at timed intervals over a 6-hour period to determine the mepivacaine plasma concentration. ⋯ Despite the high dose of mepivacaine, the plasma concentrations stayed below 6.0 micrograms/ml, with one exception, although no clinical signs of local anesthetic toxicity were observed. Plasma pharmacokinetic variables of mepivacaine were as follows: Cmax: 4.22 mg.l-1 (SD, 1.28); Tmax: 0.99 hours (SD, 0.76); T1/2: 3.25 hours (SD, 1.12); CL 0.55 1.hour-1.kg-1.