970 resultados para peripheral nerve block
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Introduction & Objectifs : Pour assurer lanalgsie postopratoire, lanesthsiste dispose, en plus des diffrentes classes de mdicaments administrs par voie orale ou intraveineuse, de diverses techniques pour bloquer linflux nerveux douloureux en administrant les anesthsiques locaux (AL) de manire centrale ou priphrique. La ropivacane (ROP), un AL longue dure daction, est un mdicament de premire intention partout dans le monde, en raison de sa grande efficacit et de son faible risque de toxicit. Contrairement certains pays, la ROP n'est toujours pas indique au Canada pour la rachianesthsie (bloc central) en raison d'un manque de donnes probantes. Jusqu' prsent, les efforts de recherche ont essentiellement port sur la scurit ainsi que sur la dure daction du mdicament lorsquadministr par voie spinale. De plus, les doses optimales de ROP pour lanesthsie rgionale priphrique ne sont pas encore prcisment connues. La posologie devrait tre adapte au site dadministration ainsi qu lintensit et la dure du stimulus produit par la chirurgie. Ultimement, cela permettrait aux cliniciens didentifier le rgime optimal en fonction des facteurs dmographiques qui pourraient affecter la pharmacocintique (PK) et la pharmacodynamie (PD) de lAL (objectif global de ces travaux). Validation de la Mthode Analytique Manuscrit 1 : Une mthode analytique spcifique et sensible permettant de dterminer les concentrations plasmatiques de ROP a dabord t optimise et valide. Validation du Biomarqueur Manuscrit 2 : Nous avons ensuite mis au point et valu la fiabilit dune mthode quantitative base sur la mesure du seuil de perception sensorielle (CPT) chez le volontaire sain. Ce test ncessite lapplication dun courant lectrique transcutan qui augmente graduellement et qui, selon la frquence choisie, est capable de stimuler spcifiquement les fibres nerveuses impliques dans le cheminement de linflux nerveux douloureux. Les rsultats obtenus chez les volontaires sains indiquent que la mesure CPT est fiable, reproductible et permet de suivre lvolution temporelle du bloc sensitif. tudes cliniques Manuscrit 3 : Nous avons ensuite caractris, pendant plus de 72 h, labsorption systmique de la ROP lorsquadministre pour un bloc du nerf fmoral chez 19 patients subissant une chirurgie du genou. Le modle PK populationnel utilis pour analyser nos rsultats comporte une absorption biphasique durant laquelle une fraction de la dose administre pntre rapidement (temps dabsorption moyen : 27 min, IC % 19 38 min) dans le flux sanguin systmique pendant que lautre partie, en provenance du site de dpt, est redistribue beaucoup plus lentement (demi-vie (T1/2) : 2.6 h, IC % 1.6 4.3 h) vers la circulation systmique. Une relation statistiquement significative entre lge de nos patients et la redistribution de lAL suggre que la permabilit tissulaire est augmente avec lge. Manuscrit 4 : Une analyse PK-PD du comportement sensitif du bloc fmoral (CPT) a t effectue. Le modle dvelopp a estim 20.2 10.1 mg la quantit de ROP ncessaire au site daction pour produire 90 % de leffet maximal (AE90). 2 X la AE90, le modle prdit un dbut daction de 23.4 12.5 min et une dure de 22.9 5.3 h. Il sagit de la premire tude ayant caractris le comportement sensitif dun bloc nerveux priphrique. Manuscrit 5 : La troisime et dernire tude clinique a t conduite chez les patients qui devaient subir une chirurgie du genou sous rachianesthsie. Tout comme pour le bloc du nerf fmoral, le modle PK le plus appropri pour nos donnes suggre que labsorption systmique de la ROP partir du liquide cphalo-rachidien est biphasique; c..d. une phase initiale (T1/2 : 49 min, IC %: 24 77 min) suivie (dlai: 18 2 min) d'une phase lgrement plus lente (T1/2 : 66 min, IC %: 36 97 min). Leffet maximal a t observ beaucoup plus rapidement, soit aux environs de 12.6 4.9 min, avant de revenir aux valeurs de base 210 55 min suivant ladministration de lagent. Ces donnes ont permis destimer une AE50 de 7.3 2.3 mg pour l'administration spinale. Conclusion : En somme, ces modles peuvent tre utiliss pour prdire lvolution temporelle du bloc sensitif de lanesthsie rachidienne et priphrique (fmorale), et par consquent, optimiser lutilisation clinique de la ROP en fonction des besoins des cliniciens, notamment en ce qui a trait lge du patient.
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Las cirugas reconstructivas mltiples de miembros inferiores son intervenciones quirrgicas que implican un difcil manejo analgsico en el postoperatorio, actualmente la tcnica analgsica usada es la analgesia peridural; sin embargo los efectos adversos asociados a esta no la hacen una tcnica ideal para manejo de dolor. Los bloqueos de nervio perifrico han aparecido como una alternativa para el manejo del dolor; pero no se ha difundido ampliamente su uso. Se pretende evaluar la disminucin de efectos adversos con el uso de bloqueos de nervio perifrico sobre la analgesia epidural. Este estudio piloto inicial se realizo para verificar efectividad tcnicas a usar y problemas que se pudieran presentar. Se aplico el protocolo en 23 pacientes que fueron llevados a ciruga de miembros inferiores, se dividieron en 2 grupos 11 recibieron bloqueos de nervio perifrico y 12 analgesia epidural. Se les realizo seguimiento por 48 horas y se evalu el control del dolor, consumo de opioides y efectos adversos. El tiempo de colocacin del bloqueo fue similar en ambos grupos, el grupo de bloqueos presento menos episodios de dolor y menos episodios de dolor severo. No se presento retencin urinaria en ningn paciente pero en el grupo de epidural se presento mayor incidencia de nausea y vomito (60% vs 45%). Se encontr que los bloqueos de nervio perifrico son una adecuada opcin para el manejo del dolor en este tipo de cirugas; y al parecer disminuye la incidencia de eventos adversos asociados a la analgesia epidural.
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El presente trabajo es un captulo de libro titulado Anestesia Regional y Perifrica Guiada por Ultrasonido en el Paciente Crtico que ser incluido en la ltima edicin del libro Manual de Ultrasonido en Terapia Intensiva y Emergencias cuyo editor es el Doctor Jos de Jess Rincn Salas y que ser publicado por la Editorial Prado de Mxico para distribucin latinoamericana desde dicho pas. Por solicitud del editor y teniendo en cuenta el enfoque del libro, el presente trabajo est dirigido a estudiantes de formacin, mdicos graduados y especialistas en las reas de cuidado intensivo, anestesiologa, dolor, medicina interna y medicina de urgencias. Tiene como propsito empapar de conocimientos necesarios y prcticos en anestesia regional a personas que usualmente no han tenido contacto con la anestesia regional, pues desafortunadamente slo en los ltimos aos ha sido posible que la anestesia regional haya comenzado a salir de las salas de ciruga, mbito donde ha estado confinada tradicionalmente. El lenguaje utilizado es sencillo y el captulo ha sido escrito para que sea fcil de leer y consultar, dejando as mensajes muy claros sobre la utilidad, viabilidad e implicaciones que tiene el uso de anestesia regional guiada por ultrasonido en cuidado intensivo. Los autores esperamos que de esta manera, el presente captulo permita continuar superando los obstculos que se interponen entre los invaluables beneficios de la anestesia regional y los pacientes de cuidado intensivo que necesitan de ella.
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A major concern with the use of continuous peripheral nerve block is the difficulty encountered in placing the catheters close enough to the nerves to accomplish effective analgesia. The aim of this study was to investigate if a self-coiling catheter would remain close to the sciatic nerve once introduced through needles placed under ultrasound guidance and if contrast dye injected through the pigtail catheter made direct contact to the nerves.
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Little is known about the learning of the skills needed to perform ultrasound- or nerve stimulator-guided peripheral nerve blocks. The aim of this study was to compare the learning curves of residents trained in ultrasound guidance versus residents trained in nerve stimulation for axillary brachial plexus block. Ten residents with no previous experience with using ultrasound received ultrasound training and another ten residents with no previous experience with using nerve stimulation received nerve stimulation training. The novices' learning curves were generated by retrospective data analysis out of our electronic anaesthesia database. Individual success rates were pooled, and the institutional learning curve was calculated using a bootstrapping technique in combination with a Monte Carlo simulation procedure. The skills required to perform successful ultrasound-guided axillary brachial plexus block can be learnt faster and lead to a higher final success rate compared to nerve stimulator-guided axillary brachial plexus block.
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OBJECTIVES Sonographic guidance for peripheral nerve anesthesia has proven increasingly successful in clinical practice; however, fears that a change to sonographically guided regional anesthesia may impair the block quality and operating room work flow persist in certain units. In this retrospective cohort study, block quality and patient satisfaction during the transition period from nerve stimulator to sonographic guidance for axillary brachial plexus anesthesia in a tertiary referral center were investigated. METHODS Anesthesia records of all patients who had elective surgery of the wrist or hand during the transition time (September 1, 2006-August 25, 2007) were reviewed for block success, placement time, anesthesiologist training level, local anesthetic volume, and requirement of additional analgesics. Postoperative records were reviewed, and patient satisfaction was assessed by telephone interviews in matched subgroups. RESULTS Of 415 blocks, 341 were sonographically guided, and 74 were nerve stimulator guided. Sonographically guided blocks were mostly performed by novices, whereas nerve stimulator-guided blocks were performed by advanced users (72.3% versus 14%; P < .001). Block performance times and success rates were similar in both groups. In sonographically guided blocks, significantly less local anesthetics were applied compared to nerve stimulator-guided blocks (mean SD, 36.1 7.1 versus 43.9 6.1 mL; P< .001), and less opioids were required (fentanyl, 66.1 30 versus 90 62 g; P< .001). Interviewed patients reported significantly less procedure-related discomfort, pain, and prolonged procedure time when block placement was sonographically guided (2% versus 20%; P = .002). CONCLUSIONS Transition from nerve stimulator to sonographic guidance for axillary brachial plexus blocks did not change block performance times or success rates. Patient satisfaction was improved even during the early institutional transition period.
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In view of the relevance of the mylohyoid nerve to clinical difficulties in achieving deep analgesia of the lower incisors, a dissection study was undertaken. Dissections from 29 adult cadavers of both sexes were studied with the aid of a dissecting microscope. The following observations were made: a supplementary branch of the mylohyoid nerve entered the mandible through accessory foramina in the lingual side of the mandibular symphysis in 50% of the cases; it generrally arose from the right side (76.9%) and entered the inferior retromental foramen (84.6%); the mylohyoid nerve branch either ended directly in the incisor teeth and the gingiva or joined the ipsilateral or contralateral incisive nerve. In view of this information concerning the high incidence of possible involvement of the mylohyoid nerve in mandibular sensory innervation, it is advisable to block it whenever intervention in the lower incisors is indicated. Routine mylohyoid injection is recommended after mental nerve block. If the inferior alveolar nerve is chosen for anesthetic purposes, additional mylohyoid injection should be given only if pain persists. The mylohyoid injection should be given at the inferior retromental foramen on the median aspect of the inferior border of the mandible through extraoral approach.
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The sheep is a popular animal model for human biomechanical research involving invasive surgery on the hind limb. These painful procedures can only be ethically justified with the application of adequate analgesia protocols. Regional anaesthesia as an adjunct to general anaesthesia may markedly improve well-being of these experimental animals during the postoperative period due to a higher analgesic efficacy when compared with systemic drugs, and may therefore reduce stress and consequently the severity of such studies. As a first step 14 sheep cadavers were used to establish a new technique for the peripheral blockade of the sciatic and the femoral nerves under sonographic guidance and to evaluate the success rate by determination of the colorization of both nerves after an injection of 0.5mL of a 0.1% methylene blue solution. First, both nerves were visualized sonographically. Then, methylene blue solution was injected and subsequently the length of colorization was measured by gross anatomical dissection of the target nerves. Twenty-four sciatic nerves were identified sonographically in 12 out of 13 cadavers. In one animal, the nerve could not be ascertained unequivocally and, consequently, nerve colorization failed. Twenty femoral nerves were located by ultrasound in 10 out of 13 cadavers. In three cadavers, signs of autolysis impeded the scan. This study provides a detailed anatomical description of the localization of the sciatic and the femoral nerves and presents an effective and safe yet simple and rapid technique for performing peripheral nerve blocks with a high success rate.
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This article describes the clinical applicability of a nerve stimulatorguided technique, previously described in dogs, to block the sciatic and the femoral nerves in 4 pet rabbits (Oryctolagus cuniculus) undergoing hind limb surgeries. Preanesthetic intramuscular doses of medetomidine (0.08mg/kg), ketamine (15mg/kg), and buprenorphine (0.03mg/kg) were administered to the rabbit patients. The rabbits were intubated and general anesthesia was maintained using isoflurane in oxygen. The sciatic-femoral nerve block was performed with 2% lidocaine at a volume of 0.05mL/kg/nerve. Sciatic-femoral block was feasible in rabbits, and the motoric responses following electrical stimulation of both nerves were consistent with those reported in dogs after successful nerve location. Iatrogenic complications, namely nerve damage and local anesthetic toxicity, did not occur. Based on these results, the authors conclude that the sciatic-femoral nerve block described in dogs can be safely performed in rabbits. Clinical trials are required to assess the analgesic efficacy of the combined sciatic-femoral nerve block in rabbits as a part of multimodal pain management.
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The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg1) or NaCl 0.9% (group C; 0.3 mL kg1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg1) was administered each time the VAS was 40 mm or the 4Avet was 5. At T390 dogs received buprenorphine (0.02 mg kg1). Data were compared using MannWhitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.
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Background and objectives: Peripheral nerve blockade requires regional anesthesia skills that are taught in several formats and assessing technical proficiency has shifted from fulfillment of quotas to comprehensive procedural evaluation. Complete analgesia is the clinical endpoint validating successful nerve blockade but patient, technical and procedural factors influence this result. The purpose of this study was to determine if physician trainee or nurse anesthetist administered sciatic nerve blockade influence postoperative pain scores and opioid analgesic requirements and if patient factors, technique and repetition influence this outcome. Method: Sciatic nerve blockade by nerve stimulation and ultrasound based techniques were performed by senior anesthesiology resident trainees and nurse anesthetists under the supervision of regional anesthesia faculty. Preoperative patient characteristics including obesity, trauma, chronic pain, opioid use and preoperative pain scores were recorded and compared to the post-procedure pain scores and opioid analgesic requirements upon discharge from the post-anesthesia care unit and 24 hours following sciatic nerve blockade. Results: 93 patients received sciatic nerve blockade from 22 nurse anesthetists and 21 residents during 36 months. A significant relation between training background and improved pain scores was not demonstrated but transition from nerve stimulation to ultrasound guided techniques lowered immediate opioid usage in all groups. Patients with pre-existing chronic opioid use had higher postoperative pain scores and opioid dosages following nerve block. Conclusion: Patient analgesia should be an integral measure of proficiency in regional anesthesia techniques and evaluating this procedure outcome for all practitioners throughout their training and beyond graduation will longitudinally assess technical expertise.
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Cell-material interactions are crucial for cell adhesion and proliferation on biomaterial surfaces. Immobilization of biomolecules leads to the formation of biomimetic substrates, improving cell response. We introduced RGD (Arg-Gly-Asp) sequences on poly--caprolactone (PCL) film surfaces using thiol chemistry to enhance Schwann cell (SC) response. XPS elemental analysis indicated an estimate of 2-3% peptide functionalization on the PCL surface, comparable with carbodiimide chemistry. Contact angle was not remarkably reduced; hence, cell response was only affected by chemical cues on the film surface. Adhesion and proliferation of Schwann cells were enhanced after PCL modification. Particularly, RGD immobilization increased cell attachment up to 40% after 6 h of culture. It was demonstrated that SC morphology changed from round to very elongated shape when surface modification was carried out, with an increase in the length of cellular processes up to 50% after 5 days of culture. Finally RGD immobilization triggered the formation of focal adhesion related to higher cell spreading. In summary, this study provides a method for immobilization of biomolecules on PCL films to be used in peripheral nerve repair, as demonstrated by the enhanced response of Schwann cells.
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Platyhelminthes occupy a unique position in nerve-muscle evolution, being the most primitive of metazoan phyla. Essentially, their nervous system consists of an archaic brain and associated pairs of longitudinal nerve cords cross-linked as an orthogon by transverse commissures. Confocal imaging reveals that these central nervous system elements are in continuity with an array of peripheral nerve plexuses which innervate a well-differentiated grid work of somatic muscle as well as a complexity of myofibres associated with organs of attachment, feeding, and reproduction. Electrophysiological studies of flatworm muscles have exposed a diversity of voltage-activated ion channels that influence muscle contractile events. Neuronal cell types are mainly multi- and bi-polar and highly secretory in nature, producing a heterogeneity of vesicular inclusions whose contents have been identified cytochemically to include all three major types of cholinergic, aminergic, and peptidergic messenger molecules. A landmark discovery in flatworm neurobiology was the biochemical isolation and amino acid sequencing of two groups of native neuropeptides: neuropeptide F and FMRFamide-related peptides (FaRPs). Both families of neuropeptide are abundant and broadly distributed in platyhelminths, occurring in neuronal vesicles in representatives of all major flatworm taxa. Dual localization studies have revealed that peptidergic and cholinergic substances occupy neuronal sets separate from those of serotoninergic components. The physiological actions of neuronal messengers in flatworms are beginning to be established, and where examined, FaRPs and 5-HT are myoexcitatory, while cholinomimetic substances are generally inhibitory. There is immunocytochemical evidence that FaRPs and 5-HT have a regulatory role in the mechanism of egg assembly. Use of muscle strips and (or) muscle fibres from free-living and parasitic flatworms has provided baseline information to indicate that muscle responses to FaRPs are mediated by a G-protein-coupled receptor, and that the signal transduction pathway for contraction involves the second messengers cAMP and protein kinase C.
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The purpose of this study was to define pathological abnormalities in the peripheral nerve of a large animal model of long-duration type 1 diabetes and also to determine the effects of treatment with sulindac. Detailed morphometric studies were performed to define nerve fiber and endoneurial capillary pathology in 6 control dogs, 6 type 1 diabetic dogs treated with insulin, and 6 type 1 diabetic dogs treated with insulin and sulindac for 4 years. Myelinated fiber and regenerative cluster density showed a non-significant trend toward a reduction in diabetic compared to control animals, which was prevented by treatment with sulindac. Unmyelinated fiber density did not differ among groups. However, diabetic animals showed a non-significant trend toward an increase in axon diameter (p <0.07), with a shift of the size frequency distribution towards larger axons, which was not prevented by treatment with sulindac. Endoneurial capillary density and luminal area showed a non-significant trend toward an increase in diabetic animals, which was prevented with sulindac treatment. Endoneurial capillary basement membrane area was significantly increased (p <0.05) in diabetic animals, but was not prevented with sulindac treatment. We conclude that the type 1 diabetic dog demonstrates minor structural abnormalities in the nerve fibers and endoneurial capillaries of the sciatic nerve, and treatment with sulindac ameliorates some but not all of these abnormalities.
