Articles: nerve-block.
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Anesthesia and analgesia · Aug 2001
A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.
We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.
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Case Reports
Ipsilateral thoraco-lumbar anaesthesia and paravertebral spread after low thoracic paravertebral injection.
We report ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast after injection through a thoracic paravertebral catheter that was placed at the right T8-9 spinal level for pain management in a patient with multiple fractured ribs. We review the literature and describe the subendothoracic fascial communication between the thoracic paravertebral space and the retroperitoneal lumbar paravertebral region, which we propose, is the anatomical basis for ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast in our patient.
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Anesthesia and analgesia · Aug 2001
An evaluation of the infraclavicular block via a modified approach of the Raj technique.
Infraclavicular plexus block has recently become a technique of increasing interest. However, no approach has provided easily identifiable landmarks, good conditions for catheter placement, and lack of complications (mainly pneumothorax). We describe a modified approach of the Raj technique based on the identification of the anterior acromial process, jugular notch, and emergence of the axillary artery within the axillary fossa, with the arm abducted to 90 degrees and elevated by approximately 30 degrees. We evaluated the clinical characteristics of this approach by injecting 40 to 50 mL of ropivacaine 0.6% in 150 patients scheduled for elective surgery of the forearm, wrist, or hand. Success was defined as a sensory block of the 5 nerves with territories distal to the elbow within 30 min after performing the block. The success rate was 97% when a distal response (flexion or extension of the wrist or fingers) was elicited and 44% when a proximal (contraction of the triceps, biceps) was obtained using a nerve stimulator. Complications were rare: aspiration of blood was seen in 2% of patients and hematoma was seen at the puncture site in 0.6%; no pneumothorax occurred. Eleven patients (7%) complained of some pain during the procedure. We conclude that the modified approach of the Raj technique for infraclavicular block is very effective when a distal nerve stimulator response is obtained with a small complication rate and a high degree of patient satisfaction. ⋯ We describe a modified approach of the Raj technique for the infraclavicular brachial plexus. The elicitation of a distal nerve stimulator response is associated with a high success rate, a low incidence of complications and a high degree of patient satisfaction.
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Anesthesia and analgesia · Aug 2001
The pharmacokinetics and pharmacodynamics of bupivacaine-loaded microspheres on a brachial plexus block model in sheep.
We evaluated bupivacaine-loaded microspheres (B-Ms) using a brachial plexus block model in sheep. In the first step, pharmacokinetic characterization of 75 mg bupivacaine hydrochloride (B-HCl) (IV infusion and brachial plexus block) was performed (n = 12). In the second step, a brachial plexus block dose response study of B-HCl was performed with 37.5 mg, 75 mg, 150 mg, 300 mg, and 750 mg. As a comparison, evaluations were performed using a 750-mg bupivacaine base (B). In the third step, evaluations of brachial plexus block were performed with B-Ms (750 mg of B as B-Ms) using two formulations, 60/40 and 50/50 (w/w %); drug-free microspheres were also evaluated. Toxicity evaluations were also performed after IV administration of B-HCl (750 mg and 300 mg), B-Ms (750 mg), and drug-free microspheres (30 mL over 1 min). As the B-HCl dose increased, the time of onset of block decreased and the duration of complete motor blockade increased at the expense of an increase in bupivacaine plasma concentrations. The time of maximum concentration appeared to be independent of the B-HCl dose. In brachial plexus block, a 37.5-mg dose of B-HCl did not induce motor blockade whereas a dose of 750 mg of B-HCl was clinically toxic. In the case of IV administration, doses of 300 mg of B-HCl were as toxic as 750 mg of B-HCl. Compared with the 75 mg of B-HCl administration for brachial plexus block, administration of 750 mg of B as B-Ms increased the duration of complete motor blockade without significant difference in maximum concentration. No significant clinical difference between the two formulations of B-Ms was demonstrated. The IV administration of B-Ms was safe. We conclude that the controlled release of bupivacaine from microspheres prolonged the brachial plexus block without obvious toxicity. ⋯ Administration of 750 mg of bupivacaine as loaded-microspheres resulted in prolongation of brachial plexus block in sheep. The peak plasma concentration was not significantly larger than that obtained with 75 mg of plain bupivacaine. The motor blockade was increased more than six times compared with 75 mg plain bupivacaine.
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Randomized Controlled Trial Clinical Trial
Intercostal nerve block with Bupivacaine for post-thoracotomy pain relief in children.
The purpose of the study is to evaluate the efficacy of Intercostal Nerve Block (ICB) with Bupivacaine (BUP) to produce satisfactory analgesia after thoracotomy in children. We studied 20 children aged between 5 and 12 years, scheduled for thoracotomy under general anaesthesia. The children were randomly divided into two groups. ⋯ The mean duration of postoperative analgesia produced was longer in the BUP group (p < 0.001). None of the children in BUP group suffered from BUP toxicity, while in the control group a high incidence of vomiting and nausea was noticed (p < 0.005). It is concluded that ICB with BUP produces satisfactory and safe analgesia for the early postoperative period after thoracotomy in children.