Articles: nerve-block.
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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.
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Randomized Controlled Trial Comparative Study Clinical Trial
Use of post-tetanic count in assessment of a repetitive vecuronium-induced neuromuscular block.
In order to evaluate the use of the post-tetanic count (PTC) method during repetitive administration of vecuronium, we studied 20 patients allocated randomly to one of two groups: 10 patients received droperidol-fentanyl anaesthesia (control group); 10 other patients were given droperidol-fentanyl anaesthesia modified subsequently by addition of 0.5% isoflurane (isoflurane group). Before tracheal intubation, a bolus dose of vecuronium 0.08 mg kg-1 was given i.v. followed by repeated doses of 0.03 mg kg-1. The twitch response of adductor pollicis was recorded after supramaximal stimulation of the ulnar nerve at the wrist using a Myograph 2000 neuromuscular transmission analyser. ⋯ In the isoflurane group, the relationship between PTC and time to first reaction to TOF stimulation remained unchanged after addition of isoflurane. However, isoflurane caused a significant prolongation of the duration of intense block and a corresponding lower PTC in all patients. We conclude that PTC is a reliable method to evaluate intense neuromuscular block caused by vecuronium, even after repetitive administration of the drug and in combination with 0.5% isoflurane.
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Comparative Study
Incidence of lingual nerve trauma and postinjection complications in conventional mandibular block anesthesia.
Trauma to the lingual nerve is potential risk factor for patients receiving mandibular block anesthesia. This paper describes the results of a patient survey of 9,587 conventional mandibular blocks received by 2,289 adults. The incidence of lingual nerve trauma and postinjection complications is reported along with an associated analysis of the duration of complications, procedures at the time of incident, the side of occurrence (right or left), and gender ratios. In addition, recommendations for patient evaluation, treatment, and follow-up care are discussed.
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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.