Evaluation of lidocaine for brachial plexus blockade in eastern box turtles (Terrapene carolina carolina).

OBJECTIVE: To evaluate latency and duration of a brachial plexus block technique in eastern box turtles performed with 2% lidocaine at three dose rates. STUDY DESIGN: Prospective, randomized, blinded crossover study. ANIMALS: Adult eastern box turtles, two for drug dose evaluation and a group of six (three male, three female) weighing 432 ± 40 g (mean ± standard deviation) for the main study. METHODS: Animals were randomly assigned to four brachial plexus blocks with lidocaine at 5, 10 and 20 mg kg-1 or 0.9% saline (treatments LID5, LID10, LID20 and CON, respectively), separated by 1 week. Treatment side was randomized and blocks were performed unilaterally. Baseline observations of mentation, heart rate (HR), respiratory rate (fR), skin temperature and limb response to manipulation or toe pinch were evaluated. Assessments were made every 10 minutes until 1 hour of normal sensory and motor function to the treated thoracic limb, or for a total of 2 hours if no block was evident. RESULTS: Motor and sensory blockade was achieved in treatments LID10 and LID20 in one turtle, with a latency of 10 minutes and duration of 50 minutes for both doses. Raising of the ipsilateral lower palpebra occurred with both blocks. Turtles administered lidocaine experienced higher HR compared with CON, and HR decreased over time for all individuals. Mentation and fR were not changed with any lidocaine dose. CONCLUSIONS: The technique was unreliable in producing brachial plexus motor and sensory blockade at the lidocaine doses evaluated in this study. HR was higher in lidocaine-administered turtles but remained within normal limits for the species. No change in mentation or fR was observed among treatments. CLINICAL RELEVANCE: General anesthesia with systemic analgesia is recommended for surgical procedures involving the chelonian thoracic limb. Further studies are needed to optimize a brachial plexus block in this species.

Comparison of 2 blind approaches to the paravertebral brachial plexus regional block in canine cadavers.

The paravertebral brachial plexus block (PVB) provides thoracic limb analgesia. The objective was to describe a blind craniocaudal (CC) approach to the PVB and compare its accuracy, time, and difficulty of performance with a blind dorsoventral (DV) approach. The operator was initially trained by experienced clinicians to perform both approaches on 5 cadavers. Next, a CC or DV approach to the PVB was performed on both thoracic limbs of 20 cadavers (20 for each approach). Methylene blue dye was equally divided into 4 aliquots to stain the ventral branches of the sixth to eighth cervical and first thoracic spinal nerves. Successfully stained (stain ≥ 1 cm) spinal nerves were counted. The time to perform each approach was recorded and ease of performance was scored using a numerical scale (1 "easy" to 4 "difficult"). The phrenic nerve was checked for stain. A Wilcoxon signed-rank test was used to compare approaches. The data are presented as median (interquartile range; minimum to maximum range). The number of stained nerves with the CC approach 3 (1; 2 to 4), was higher than the DV approach 2 (2; 0 to 4) (P = 0.002). The time (in seconds) to perform the CC approach 125 (79; 70 to 194), was not different from the DV approach 142 (54; 101 to 232) (P = 0.084). The CC approach 2 (2; 1 to 4) was easier to perform than the DV approach 3 (1; 2 to 4) (P = 0.024). No phrenic nerve staining was observed with either approach. The CC approach is an alternative to the DV approach for performing the PVB in dogs.

Le bloc du plexus brachial paravertébral (PVB) fournit une analgésie du membre thoracique. L'objectif était de décrire une approche craniocaudale (CC) aveugle du PVB et de comparer sa précision, son temps et sa difficulté de performance avec une approche dorso-ventrale (DV) aveugle. L'opérateur a été initialement formé par des cliniciens expérimentés pour effectuer les deux approches sur cinq cadavres. Ensuite, une approche CC ou DV du PVB a été réalisée sur les deux membres thoraciques de 20 cadavres (20 pour chaque approche). Le colorant bleu de méthylène a été divisé de manière égale en quatre aliquotes pour colorer les branches ventrales des sixième à huitième nerfs cervicaux et rachidiens thoraciques. Les nerfs spinaux colorés avec succès (coloration ≥ 1 cm) ont été comptés. Le temps d'exécution de chaque approche a été enregistré et la facilité d'exécution a été notée à l'aide d'une échelle numérique (1 « facile ¼ à 4 « difficile ¼). Le nerf phrénique a été vérifié pour la coloration. Un test des rangs signés de Wilcoxon a été utilisé pour comparer les approches. Les données sont présentées sous forme de médiane (intervalle interquartile; intervalle minimum à maximum). Le nombre de nerfs colorés avec l'approche CC 3 (1; 2 à 4) était plus élevé que l'approche DV 2 (2; 0 à 4) (P = 0,002). Le temps (en secondes) pour effectuer l'approche CC 125 (79; 70 à 194) n'était pas différent de l'approche DV 142 (54; 101 à 232) (P = 0,084). L'approche CC 2 (2; 1 à 4) était plus facile à réaliser que l'approche DV 3 (1; 2 à 4) (P = 0,024). Aucune coloration du nerf phrénique n'a été observée avec l'une ou l'autre approche. L'approche CC est une alternative à l'approche DV pour réaliser le PVB chez le chien.(Traduit par Docteur Serge Messier).

Ultrasound-guided brachial plexus block and suspected Horner's syndrome in an alpaca (Vicugna pacos) undergoing traumatic scapulo-humeral luxation reduction and articular capsule reconstruction.

Background: Alpacas are becoming more and more diffused as pets in Europe and United Kingdom, and it is not uncommon to deal with these species in large animal referral hospitals. Unfortunately, pain assessment and treatment in llamoids remain challenging, due to their instinct of hiding signs of pain and the lack of relevant scientific literature. Case Description: This report describes the use of an ultrasound-guided brachial plexus block as part of a multimodal analgesic strategy in an alpaca undergoing surgical right shoulder luxation repair. Based on the intra-operative cardiovascular stability, the post-operative comfort level, and the minimal amount of systemic analgesics needed, it can be concluded that the block appeared effective and contributed to the peri-operative pain management. After recovery from general anesthesia, drooping of the right upper eyelid was observed and persisted for approximately 10 hours. This finding could be interpreted as a Horner's syndrome-like clinical sign and be a minor complication of the block, as previously described in other species. Conclusion: Despite the minor complication here reported, and the difficulty in assessing intra- and post-operative nociception and pain in camelids, it can be concluded that the use of a brachial plexus block could be a valuable option when desensitization of the forelimb is required.

Feasibility of a blind perineural injection technique for brachial plexus blockade in eastern box turtles (Terrapene carolina carolina): a cadaver study.

OBJECTIVE: To describe the anatomy of the brachial plexus in eastern box turtles (Terrapene carolina carolina), develop a blind perineural injection technique for brachial plexus blockade and evaluate the distribution of three volumes of new methylene blue dye for injection in cadavers. STUDY DESIGN: Prospective, randomized, blinded cadaveric study. ANIMALS: A total of 24 frozen-thawed box turtle cadavers; two turtles identified with shoulder injuries were subsequently excluded from the study. The remaining 22 turtles weighed 397 (190-581) g, median (range). METHODS: The brachial plexus and regional anatomy were identified by dissection of seven cadavers to determine anatomic landmarks for a perineural injection technique. This technique was tested by randomizing 15 cadavers into one of three groups to be injected bilaterally with one of three volumes (0.1, 0.2 or 0.3 mL) of methylene blue dye 1% aqueous solution. Investigators blinded to the assigned group dissected cadavers 15 minutes after injection and used staining of the four cervical spinal nerves (C5-C8; 25% for each nerve) to record a staining score of the brachial plexus (0-100%). RESULTS: Based on descriptions of the anatomy of the brachial plexus, an injection technique was designed. Injections of 0.1 mL methylene blue dye resulted in nine/10 injections with 100% nerve stained, and one/10 injection with 50% (two) nerves stained. All injections of 0.2 or 0.3 mL of methylene blue dye resulted in 100% nerves stained. CONCLUSIONS AND CLINICAL RELEVANCE: Perineural injection of the brachial plexus with 0.1, 0.2 or 0.3 mL methylene blue dye was successful in 29/30 injections in box turtle cadavers weighing 190-581 g. Further studies are needed to determine the minimum volume of injectate that can be successfully used for this technique, and to evaluate its application and efficacy in live turtles.

Ultrasound-guided dorsal approach for the brachial plexus block in common kestrels (Falco tinnunculus): a cadaver study.

OBJECTIVE: To develop an ultrasound-guided dorsal approach to the brachial plexus and to investigate the nerve distribution and staining of a dyed injectate in common kestrel (Falco tinnunculus) cadavers. STUDY DESIGN: Prospective, cadaver study. ANIMALS: A group of three common kestrel cadavers (six wings). METHODS: All cadavers were fresh-frozen at -20 °C and thawed for 10 hours at room temperature before the study. The cadavers were placed in sternal recumbency and their wings were abducted. A 8-13 MHz linear-array transducer was placed over the scapulohumeral joint, at the centre of a triangle formed by the scapula and the humerus. The brachial plexus was identified between the scapulohumeralis muscle and the pectoralis major muscle, as hypoechoic structures lying just cranially to the axillary vessels. After ultrasound-guided brachial plexus identification, a 22 gauge, 50 mm insulated needle was advanced in-plane using ultrasound visualization. A volume of 0.5 mL kg-1 of a 3:1 (2% lidocaine:methylene blue) solution was injected. Following cadaver dissection, the pattern of the spread was assessed, and the extent of nerve staining was measured with a calliper and deemed adequate if more than 0.6 cm of the nerve staining was achieved. RESULTS: The brachial plexus was clearly identified in all wings with the dorsal approach. After dye injection, all the branches of the brachial plexus defined as nerves 1-5 (N1, N2, N3, N4 and N5) were completely stained in five (83%) and partially stained in one (17%) of the six wings. CONCLUSIONS AND CLINICAL RELEVANCE: The ultrasound-guided dorsal approach allows a clear visualization of the brachial plexus structure. The injection of 0.5 mL kg-1of a lidocaine/dye solution produced complete nerve staining in most cases. Further in vivo studies are mandatory to confirm the clinical efficacy of this locoregional anaesthesia technique in common kestrels (Falco tinnunculus).

Ultrasonographic study of a modified axillary approach to block the major branches of the brachial plexus in dogs.

OBJECTIVE: To provide ultrasonographic mapping of the axillary region of dogs to facilitate identification of the major branches of the brachial plexus in relation to the axillary artery. STUDY DESIGN: Prospective study. ANIMALS: A total of two dog cadavers and 50 client-owned, healthy dogs weighing >15 kg. METHODS: In Phase 1, anatomical dissections were performed to identify the relation of the major brachial plexus nerves to the axillary artery. In Phase 2, with the dogs in dorsal recumbency with thoracic limbs flexed naturally, the axillary space was scanned using a linear array probe oriented on the parasagittal plane until the axis transverse to nerves was found. Then, the transducer was rotated to a slight lateral angle approximately 30° to midline. The examination aimed to identify the axillary artery and the musculocutaneous, radial, median and ulnar nerves in addition to determining their position and distribution in four predefined sectors. RESULTS: The musculocutaneous nerve was observed in all animals cranial to the axillary artery. The radial, ulnar and median nerves were distributed around the axillary artery, with >90% on the caudal aspect of the axillary artery (sectors 1 and 2). CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography identified the location of the brachial plexus nerves near the studied sectors, providing useful guidance for performing a brachial plexus nerve block.

Bloqueio do plexo braquial em jumento - relato de caso / Brachial plexus block in donkey - case report

A anestesia locorregional reduz o requerimento de agentes inalatórios e diminui as respostas autonômicas a estímulos cirúrgicos nocivos. Objetiva-se descrever um bloqueio anestésico do plexo braquial guiado por neuroestimulador em jumento, submetido à amputação do membro anterior direito. Foi realizada medicação pré-anestésica com detomidina 0,01mg.kg-1, indução com diazepam 0,05mg.kg-1 e cetamina 2mg.kg-1, todos pela via intravenosa (IV), e a manutenção da anestesia com isoflurano. O plexo braquial foi bloqueado por acesso subescapular, sendo usado neuroestimulador. Utilizou-se 1mg.kg-1 de bupivacaína 0,5% sem vasoconstritor, associada a 1mg.kg-1 de lidocaína 2% sem vasoconstrictor. Os valores de FC e ƒ durante o procedimento cirúrgico variaram de 62 a 78bpm e de 24 a 32rpm, respectivamente. Foram coletadas quatro amostras de sangue para dosagem de cortisol. Este, antes da aplicação da medicação pré-anestésica, foi de 6,4µg/dL e, 30 minutos após a MPA, foi de 2,8µg/dL. A recuperação anestésica foi rápida e sem complicações. O bloqueio do plexo braquial guiado por neuroestimulador mostrou-se eficaz em jumentos, fornecendo analgesia e anestesia satisfatória.(AU)

Locoregional anesthesia reduces the requirement for inhaled agents and reduces the autonomic responses to noxious surgical stimuli. The aim of this study was to describe an anesthetic block of the brachial plexus guided by a neurostimulator in a donkey submitted to right limb amputation. Preanesthetic medication was performed with detomidine 0.01mg.kg-1 induction with diazepam 0.05mg.kg-1 and ketamine 2mg.kg-1 all intravenously, and maintenance of anesthesia with isoflurane. The brachial plexus was blocked by subscapular access, using a neurostimulator. For this purpose, 1mg.kg -1 of bupivacaine 0.5%, without vasoconstrictor, and 1mg.kg- 1 of lidocaine 2%, without vasoconstrictor were used. The values of HR and ƒ during the surgical procedure ranged from 62 to 78bpm, and 24 to 32bpm, respectively. Four blood samples were collected for cortisol dosing. This, prior to the application of the pre-anesthetic medication was 6.4µg/dL and 30 minutes was 2.8µg/dL. Anesthesia recovery was rapid and uncomplicated. Neurostimulator-guided brachial plexus blockade proved to be effective in donkeys, providing satisfactory analgesia and anesthesia.(AU)

Comparison of 3 blind brachial plexus block techniques during maintenance of anesthesia and postoperative pain scores in dogs undergoing surgical procedures of the thoracic limb.

The degree of analgesia provided by blind techniques for brachial plexus blocks (BPBs) has not been compared in clinical cases undergoing surgery of the thoracic limb. The objective of this study was to evaluate the anesthetic conditions and postoperative analgesia resulting from 3 different BPB local anesthetic techniques in canine patients undergoing such surgery. Twenty-four client-owned dogs received a standardized premedication/induction protocol (hydromorphone and acepromazine/propofol), maintained with isoflurane in oxygen using mechanical ventilation, in a prospective, randomized, blinded clinical trial. Before surgery, dogs received 1 of 3 anatomical BPB techniques: traditional, perpendicular, or axillary, with 0.2 mL/kg body weight (BW) of bupivacaine 0.5%. Cardiorespiratory variables and isoflurane end-tidal concentrations were recorded throughout anesthesia. Scores for anesthetic maintenance (0-best to 4-responsive), recovery quality (0-not responsive to 3-responsive), and Glasgow pain scale were recorded for up to 24 h postoperatively. All dogs recovered uneventfully from anesthesia and no differences in the measured variables or scores were noted among groups, during and after anesthesia. When thoracic limb amputations in each of the 3 groups (n = 9; 4 in traditional, 3 in perpendicular, 2 in axillary) were compared to the other surgical procedures (n = 15); however, scores for anesthetic maintenance were higher [0 (0 to 1) versus 0 (0 to 0); median (interquartile range)], recovery [1 (0 to 2) versus 0 (0 to 0)], and pain [2.4 (2.4 to 3.0) versus 1.6 (1.4 to 2.2)] in the first 3 h post-extubation. Surgery times were also longer with amputations [115 min (100 to 138 min) versus 50 min (41 to 90 min)]. The 3 BPB techniques provided similar anesthesia and postoperative pain scores. Despite higher pain scores in thoracic limb amputations than in less invasive surgeries, the BPB appeared to provide significant comfort.

Le degré d'analgésie fournie par les blocs à l'aveugle du plexus brachial (BPBs) n'a pas été comparé lors de cas cliniques soumis à une chirurgie du membre thoracique. La présente étude visait à évaluer les conditions anesthésiques et l'analgésie post-opératoire résultant de trois techniques différentes d'anesthésie locale par BPB chez des patients canins soumis à une chirurgie. Vingt-quatre chiens appartenant à des propriétaires ont reçu une prémédication/induction standardisée (hydromorphone et acépromazine/propofol), avec maintien à l'isoflurane dans de l'oxygène en utilisant une ventilation mécanique, dans une étude clinique prospective, randomisée, et à l'aveugle. Avant la chirurgie, les chiens ont reçu un BPB par une des trois techniques anatomiques : traditionnelle, perpendiculaire, ou axillaire, avec 0,2 mL/kg de poids corporel de bupivacaïne 0,5 %. Les variables cardiorespiratoires et les concentrations d'isoflurane en fin d'expiration furent enregistrées tout au long de l'anesthésie. Les pointages pour le maintien de l'anesthésie (0-meilleur à 4-réactif), la qualité du rétablissement (0-non réactif à 3-réactif), et l'échelle de la douleur de Glasgow ont été notés jusqu'à 24 h post-opération. Tous les chiens ont récupéré sans problème de l'anesthésie et aucune différence mesurable dans les variables mesurées ou les pointages ne fut notée parmi les groupes, durant ou après l'anesthésie. Toutefois, lorsque les amputations du membre thoracique dans chacun des trois groupes (n = 9; 4 dans la traditionnelle, 3 dans la perpendiculaire, 2 dans l'axillaire) furent comparées aux autres procédures chirurgicales (n = 15), les pointages pour le maintien de l'anesthésie étaient plus élevés [0 (0 à 1) versus 0 (0 à 0); médiane (écart interquartile)], rétablissement [1 (0 à 2) versus 0 (0 à 0)], et douleur [2,4 (2,4 à 3,0) versus 1,6 (1,4 à 2,2)] dans les 3 h suivant l'extubation. La durée des chirurgies étaient également plus longues lors des amputations [115 min (100 à 138 min) versus 50 min (41 à 90 min)]. Les trois techniques de BPB produisaient des pointages similaires d'anesthésie et de douleur postopératoire. Malgré des pointages de douleur plus élevés lors d'amputations du membre thoracique que lors de chirurgies moins invasives, les BPB semblent fournir un confort significatif.(Traduit par Docteur Serge Messier).

Clinical comparison of two techniques of brachial plexus block for forelimb surgery in dogs.

The objective of this study was to compare two different local anaesthesia techniques for intraoperative analgesia in dogs undergoing surgical procedures distal to the mid humeral diaphysis. Thirty-two dogs were divided into two groups: the US group received an ultrasound-guided brachial plexus block at the level of the first rib and the N group received a neurostimulation-guided paravertebral brachial plexus block. Ropivacaine 0.75% at 1.5mg/kg was injected in each case. Dogs were monitored during the surgical procedure, and rescue analgesia was administered whenever the heart rate, respiratory rate or blood pressure increased more than 20% from the basal values. Success rate was defined as no need for rescue analgesia during surgery and complete blockade of the operated leg evaluated just after anaesthesia recovery. Complications were also recorded. Data was analysed using Fisher exact and Mann/Whitney tests. Success rate was observed in 14/16 (87%) dogs and in 12/16 (75%) dogs in the US and N groups, respectively (P=0.65). Complications recorded were hypotension in three cases (US group, n=1; N group, n=2) and Horner's syndrome in three cases (US group, n=1; N group, n=2; P=0.65). Both techniques were found to provide good level of analgesia that allowed performing the orthopaedic procedures from the mid humeral diaphysis and distal in the limb, without the need for further analgesia.

A sonographic investigation for the development of ultrasound-guided paravertebral brachial plexus block in dogs: cadaveric study.

OBJECTIVE: To describe a novel in-plane ultrasound (US)-guided approach to the sixth (C6), seventh (C7), eighth (C8) cervical and to the first thoracic (T1) spinal nerves. STUDY DESIGN: Prospective, descriptive, experimental anatomic study. ANIMALS: A total of seven canine Beagle cadavers. METHODS: Phase 1: One cadaver was used to define bony landmarks for the C6-T1 spinal nerves using computed tomography (CT) and magnetic resonance imaging. An US transducer was positioned lateral to the C6 vertebra. Methylene blue (0.05 mL kg-1) was injected cranial and caudal to the transverse process of C6. The probe was moved caudally to identify the cranial costal fovea of T1 and 0.1 mL kg-1 of methylene blue was injected. Full cadaver dissection was performed to assess the staining of the spinal nerves. Phase 2: The technique was repeated using a 50:50 mixture of iohexol and methylene blue in six dogs. CT verified the proximity of contrast to C6, C7, C8 and T1 nerves. Mediastinal, epidural, intravascular and pleural contamination was recorded. Methylene blue staining of the phrenic nerve was assessed by dissection. RESULTS: Phase1: The identified bony landmarks were the lamina ventralis of C6, the transverse process of C6 and C7, T1 vertebra and the first rib. Phase 2: At all the 12 sites, the C6, C7 and C8 nerves were in contact with contrast material. Contrast was demonstrated in close proximity to the anatomical location of the T1 nerve in 11/12 sites. Mediastinal, epidural and intravascular contamination was observed in six, four and two cadavers, respectively. Pleural contamination was not observed. The phrenic nerve was stained on 2/12 of sides. CONCLUSIONS AND CLINICAL RELEVANCE: In-plane US-guided blockade of the spinal roots is a feasible technique. However, because of the undesirable spreads of contrast, further research is needed to diminish the occurrence of contaminations of noble structures.

Anatomical characterization of the brachial plexus in dog cadavers and comparison of three blind techniques for blockade.

OBJECTIVES: To describe the ventral spinal nerve rami contribution to the formation of the brachial plexus (BP), and to compare ease of performing and nerve staining between three blind techniques for BP blockade in dogs. STUDY DESIGN: Prospective, randomized, blind study. ANIMALS: A total of 18 dog cadavers weighing 28.2 ± 9.7 kg (mean ± standard deviation). METHODS: Dogs were randomly assigned to two of three BP treatments: traditional approach (TA), perpendicular approach (PA), and axillary approach (AA). Dye (0.2 mL kg-1) was injected in the left BP using a spinal needle; another BP treatment was used in the right BP. Landmarks (L) included: L1, midpoint between point of the shoulder and sixth cervical (C6) transverse process; L2, scapulohumeral joint; and L3, first rib. For TA, the needle was introduced craniocaudally through L1, medial to the limb and cranial to L3. For PA, the needle was directed perpendicular and caudal to L2, aligned with L1, until cranial to L3. For AA, the needle was directed ventrodorsally, parallel and cranial to L3 until at L1. All BPs were scored for dyeing quality [0 (poor) to 5 (excellent)]. The left BP was dissected for nerve origins. Durbin test was used to compare scores (p < 0.05). RESULTS: In all dogs, the musculocutaneous nerve originated from C7 and C8; the radial nerve from C8, the first thoracic vertebra (T1) (16/18 dogs) and C7 (2/18); and the median and ulnar nerves from C8, T1 (17/18) and C7 (1/18). Respective raw scores and adjusted scores for the incomplete block design were not significantly different (p = 0.72; ranks TA 16.5, PA 19.0, AA 18.5). CONCLUSIONS AND CLINICAL RELEVANCE: The musculocutaneous, median, ulnar and radial nerves originate from C7, C8 and T1. Regardless of the technique, knowledge of anatomy and precise landmarks are relevant for correct dye dispersion.

Paravertebral brachial plexus blockade in cats: a cadaver study.

Objectives The aims of this study were to describe the paravertebral brachial plexus (PBP) blockade in cats, and compare the spread of bupivacaine-methylene blue solution (BMS) using two volumes of injection into the PBP. Methods Six cadavers (4.4 ± 1.8 kg) randomly received 0.15 ml/kg (LOW) or 0.2 ml/kg (HIGH) per injection of BMS into the PBP. The first injection was made ventral to the transverse process of the sixth cervical vertebra (nerves C6 and C7) at the emergence of nerve roots. A second injection was performed at the edge of the cranial border of the scapula and directed ventrally towards the first rib (C8 and T1). Cadavers were dissected and the presence of BMS in contact with the nerves (success rate) and length of staining were evaluated for each nerve (C6/C7/C8/T1). Length of target nerves in contact with BMS was measured and <15 mm was considered fair, ⩾15 mm sufficient and >40 mm excessive. Complications (aspiration of blood, staining of pleural space and/or spinal cord) were recorded. Paired t-test, Mann-Whitney U-test and χ2 test were used for statistical analysis when appropriate ( P <0.05). Results Eleven hemilateral brachial plexuses were injected. Aspiration of blood occurred during one injection. Inadvertent pleural or spinal staining was not observed. Success rates (positive nerve staining) in the LOW and HIGH groups, respectively, were as follows: C6: 83% and 80%; C7: 66% and 100%; C8: 66% and 100%; T1: 50% and 60% ( P >0.05). Median (range) length of nerve staining was 22 mm (15-39 mm) for LOW and 21 mm (13-35 mm) for HIGH ( P >0.05). Excessive nerve staining was not recorded. Conclusions and relevance This study describes the PBP blockade in cats with acceptable nerve staining and minimal complications. Success rate and length of nerve staining were not significantly different between the LOW and HIGH groups.

Bloqueio de plexo braquial em um bugio-ruivo (Alouatta guariba): relato de caso / Brachial plexus block in a red howler monkey (Alouatta guariba): case report

Os bloqueios regionais vêm sendo explorados e difundidos no dia a dia da medicina veterinária. O presente trabalho relata a execução do bloqueio de plexo braquial em um bugio-ruivo (Alouatta guariba) submetido à amputação de três dígitos. Foi utilizada ropivacaína para o bloqueio, com o paciente sob anestesia geral, com auxílio de neuroestimulador periférico. Quatro horas após a cirurgia e cinco horas após o bloqueio, o paciente não apresentava desconforto ou evitava a manipulação do membro operado e não foram observadas complicações. O bloqueio do plexo braquial é mais comumente utilizado quando se pretende promover analgesia e relaxamento muscular do membro torácico em procedimentos cirúrgicos distais à articulação escápulo-umeral. Há carência em estudos anatômicos sobre diversos primatas, incluindo o bugio-ruivo (Alouatta guariba). Apesar da crescente expansão da clínica de animais silvestres, ainda há lacunas no que diz respeito à execução de técnicas anestésicas em diversas espécies.(AU)

The regional blocks are being exploited and disseminated on a daily basis of veterinary medicine. This study describes the implementation of the brachial plexus block in a red howler-monkey (Alouatta guariba) that underwent amputation of three digits. Ropivacaine was employed for blocking, with the patient under general anesthesia, with the aid of a peripheral nerve stimulator. Four hours after surgery, and five hours after the blockade, the patient had no discomfort nor avoided manipulation of the operated limb and no complications were observed. The brachial plexus block is most commonly used when you want to promote analgesia and muscle relaxation of the forelimb in distal surgical procedures to the scapular-humeral joint. There is a lack of anatomical studies on various primates, including the red howler-monkey (Alouatta guariba). Despite the growing expansion of clinic of wild animals, there are still shortcomings with regards to the implementation of anesthetic techniques in many species.(AU)

Comparison of ultrasound- and electrostimulation-guided nerve blocks of brachial plexus in dogs.

OBJECTIVE: To compare the effectiveness of ultrasound- and electrostimulation-guided nerve blocks of the brachial plexus and to determine whether ultrasound guidance is feasible in conscious dogs. STUDY DESIGN: Blinded, crossover, experimental study. ANIMALS: Six clinically healthy adult Beagle dogs. METHODS: The nerves of the brachial plexus of the right thoracic limb were blocked under ultrasound guidance (UNB) in conscious dogs and under electrostimulation guidance (ENB) in anesthetized dogs with bupivacaine (0.4 mL kg-1, 0.25%). Saline (0.4 mL kg-1) was injected in control animals. Sensory nerve blockade was evaluated by scoring cutaneous sensation in targeted nerves. Motor nerve blockade was evaluated based on weight bearing, conscious proprioception and withdrawal reflex scores. Times to execute the technique in UNB and ENB were compared using t tests (p < 0.05). Scores for sensory and motor nerve blockades in each treatment were compared with scores before treatment and with control treatment scores using nonparametric repeated-measures two-way analysis of variance. Time to onset and duration of sensory nerve block were assessed using scores for four sensory nerve functions. A successful sensory nerve block was defined by decreases in scores for these functions. Success rates of nerve blocks were compared among treatments using McNemar's test. RESULTS: In UNB and ENB, onset times of sensory nerve blocks were 1 hour and 1.5 hours, respectively. Onset times of motor nerve blocks were 0.5 hour in both treatments. In UNB and ENB, durations of sensory nerve block were 3 hours and 0.5 hour, respectively, and durations of motor nerve block were 7.5 hours and 6.5 hours, respectively. Success rates did not differ between the techniques. CONCLUSIONS AND CLINICAL RELEVANCE: The UNB brachial plexus block had a shorter onset time and longer duration than ENB. UNB can be performed in conscious dogs or those under mild sedation.

Comparison of lidocaine and lidocaine-epinephrine for the paravertebral brachial plexus block in dogs.

OBJECTIVE: To compare the motor and sensory block efficacy and duration of a modified paravertebral brachial plexus block (PBPB) after administration of lidocaine alone (LI) or combined with epinephrine (LE). STUDY DESIGN: Prospective, randomized, blinded, crossover study. ANIMALS: A total of eight healthy female Beagle dogs. METHODS: Under general anesthesia, modified PBPB was performed on the left thoracic limb using neurostimulation and/or ultrasound guidance to administer lidocaine (2 mg kg-1; 0.2 mL kg-1) either alone (treatment LI, n = 10) or with epinephrine (1:100,000; treatment LE, n = 9). Sensory block was evaluated through reaction to a painful mechanical stimulus applied at five sites on the limb. Motor block effect was evaluated according to visual gait assessments and thoracic limb vertical force measurements under dynamic and static conditions. Data were analyzed using repeated-measures generalized estimating equations. All statistical tests were performed two-sided at the α = 0.05 significance threshold. RESULTS: The duration of sensory block did not differ significantly between treatments. Visible gait impairment was more persistent in LE than in LI (118 ± 63 minutes for LI and 163 ± 23 minutes for LE; mean ± standard deviation) (p = 0.027). At nadir value, dynamic peak vertical force was lower in LE than in LI (p = 0.007). For both dynamic and static evaluations, the nadir and the return to baseline force were delayed in LE (return to normal at 180-200 minutes) when compared with LI (130-140 minutes) (p < 0.005). CONCLUSIONS AND CLINICAL RELEVANCE: The addition of epinephrine to lidocaine prolonged the duration and increased the intensity of the regional block, as verified by visual gait assessment and kinetic analysis. No significant difference was noted between treatments regarding sensory blockade. Kinetic analysis could be useful to evaluate regional anesthetic effect in dogs.

Evaluation of an ultrasound-guided technique for axillary brachial plexus blockade in cats.

Objectives The aim of this study was to evaluate and refine an ultrasound (US)-guided technique to block the brachial plexus (BP) at the level of the axillary space in live cats. Methods Eight adult experimental cats were enrolled into the study. The animals were sedated and positioned in dorsal recumbency with the limb to be blocked abducted 90º. The US transducer was placed in the axillary region and a non-traumatic peripheral nerve block needle was inserted in-plane with respect to the transducer, medial to the BP up to the level of the axillary artery. Lidocaine 1% (0.4 ml/kg) was injected as the needle was being progressively withdrawn in a caudal-to-cranial direction. The efficacy of the block was confirmed by evaluation of the motor and sensory functions of the blocked forelimb. Motor blockade was assessed observing the position of the blocked leg on standing and walking patterns. Sensory blockade was evaluated by the stimulation of mechanical nociceptors in the dermatomes supplied by the four major sensory nerves of the distal thoracic limb. Results The BP was successfully located by US in all cases. The achieved BP block was complete in six cats (75%) and partial in the remaining two cats (25%). All animals recovered uneventfully from the sedation and the BP blocks. Conclusions and relevance The US-guided block at the axillary space evaluated in this study is a feasible, reproducible and safe technique to block the BP plexus in experimental live cats.

Ultrasound and gross anatomy of the brachial plexus and major nerves of the forelimb. An anesthetic approach using the domestic rabbit (Oyctolagus cuniculus) as an experimental model1.

PURPOSE: To update the gross and sonographic anatomy and propose landmarks to perform ultrasound-guided (US-guided) axillary brachial plexus block (BPB) in rabbits. METHODS: Forty New Zeeland's rabbit (NZR) cadavers were dissected and the nerves were trimmed, identified, measured, and photographed. Additionally, in twenty NZRs, sonographic images of brachial plexus (BP) were performed through a simple-resolution ultrasound device. The US-guided block was achieved through a minimum volume of lidocaine necessary to surround the BP roots. The effectiveness of the brachial plexus block was assessed on sensitivity and motor functions. RESULTS: The BP resulted from connections between the ventral branches of the last four cervical spinal nerves and the first thoracic spinal nerve. In the axillary sonoanatomy, the BP appeared as an agglomerate of small, round hypoechoic structures surrounded by a thin hyperechoic ring. The amount of time and the minimum volume required to perform was 4.3 ± 2.3 min and 0.8 ± 0.3ml, respectively. CONCLUSIONS: The gross and sonographic anatomy of the BP showed uncommon morphological variations. Moreover, from sonographic landmarks, we showed complete reproducibility of the axillary US-guided brachial plexus block with simple resolution equipment and small volume of anesthetics required.

Ultrasound and gross anatomy of the brachial plexus and major nerves of the forelimb. An anesthetic approach using the domestic rabbit (Oyctolagus cuniculus) as an experimental model1

PURPOSE: To update the gross and sonographic anatomy and propose landmarks to perform ultrasound-guided (US-guided) axillary brachial plexus block (BPB) in rabbits. METHODS: Forty New Zeeland's rabbit (NZR) cadavers were dissected and the nerves were trimmed, identified, measured, and photographed. Additionally, in twenty NZRs, sonographic images of brachial plexus (BP) were performed through a simple-resolution ultrasound device. The US-guided block was achieved through a minimum volume of lidocaine necessary to surround the BP roots. The effectiveness of the brachial plexus block was assessed on sensitivity and motor functions. RESULTS: The BP resulted from connections between the ventral branches of the last four cervical spinal nerves and the first thoracic spinal nerve. In the axillary sonoanatomy, the BP appeared as an agglomerate of small, round hypoechoic structures surrounded by a thin hyperechoic ring. The amount of time and the minimum volume required to perform was 4.3 ± 2.3 min and 0.8 ± 0.3ml, respectively. CONCLUSIONS: The gross and sonographic anatomy of the BP showed uncommon morphological variations. Moreover, from sonographic landmarks, we showed complete reproducibility of the axillary US-guided brachial plexus block with simple resolution equipment and small volume of anesthetics required.