Brachial plexus block with or without ultrasound guidance
ABSTRACT Should ultrasound or nerve stimulation be used for brachial plexus blocks? We investigated last year's literature to help answer this question.
Many of the reports concluded that ultrasound guidance may provide a higher success rate for brachial plexus blocks than guidance by nerve stimulator. However, the studies were not large enough to conclude that ultrasound will reduce the risk of nerve injury, local anesthetic toxicity or pneumothorax. Ultrasound may reveal anatomical variations of importance for performing brachial plexus blocks. For postoperative analgesia, 5 ml of ropivacaine 0.5% has been sufficient for an ultrasound-guided interscalene block. For peroperative anesthesia, as much as 42 ml of a local anesthetic mixture was calculated to be appropriate for an ultrasound-guided supraclavicular method. For the future, we notice that three-dimensional and four-dimensional ultrasound technology may facilitate visualizing the needle, the nerves and the local anesthetic distribution. Impedance measurements may be helpful for nerve blocks not guided by ultrasound.
We think that the literature gives a sufficient basis to recommend the use of ultrasound for guidance of brachial plexus blocks. The potential for ultrasound to improve efficacy and reduce complications of brachial plexus blocks requires larger scaled studies.
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- "Ultrasound demonstrates in real time the relative locations of the needle, the nerves of interest, the structures to be avoided by the needle (i.e. blood vessels) and the distribution of local anaesthetic injected (Klaastad et al. 2009). For these reasons, ultrasound-guided nerve blocks may be advantageous compared to 'blind' techniques (including neurostimulation). "
ABSTRACT: OBJECTIVE: To determine if the use of needle enhancing software facilitate injection technique in ultrasound-guided peripheral nerve blocks. STUDY DESIGN: Prospective, blinded, randomized controlled trial. ANIMALS: Eight hind limbs from canine cadavers. METHODS: The limbs were randomly allocated to two groups; software on (group I) and software off (group II). Eight anaesthetists with no previous experience of ultrasound-guided regional anaesthesia were recruited. Thirty-six procedures were carried out (18 per group). After sciatic nerve visualisation via ultrasonography, the anaesthetist introduced a needle guided by ultrasonography. When the tip of the needle was considered by the anaesthetist to be as close as possible to the nerve without touching it, 0.05 mL of methylene blue dye was injected. Parameters evaluated included: number of attempts to visualise the needle with ultrasonography, time spent to perform the technique, subjective evaluation of ease of needle visualisation, proximity of the tip of the needle to the nerve, and, at dissection of the leg, inoculation site of the dye in relation to the nerve. RESULTS: Significant differences between groups were identified in relation to the number of attempts (group I: median 1, IQR: 1 - 1 attempts versus group II: median 1, IQR: 1 - 4 attempts, p = 0.019), and the relationship between the dye and the nerve during hind limb dissection (72.2% of the nerves were stained in group I versus 16.6% in group II, p = 0.003). No significant difference between groups was observed with respect to the time taken to perform the procedure (group I: median 25.5, IQR: 18.4 - 44.3 seconds versus group II: median 35.7, IQR: 18.6-78.72 seconds, p = 0.31), subjective evaluation of the needle visualization (p = 0.45) or distance between the tip of the needle and the nerve as measured from the ultrasound screen (p = 0.23). CONCLUSIONS AND CLINICAL RELEVANCE: This study identified greater success rate in nerve staining when the needle enhancing software was used. The results suggest that the use of this technique could improve injection technique amongst inexperienced anaesthetists performing ultrasound-guided peripheral nerve blocks in dogs.Veterinary Anaesthesia and Analgesia 04/2013; 40(6). DOI:10.1111/vaa.12043 · 1.78 Impact Factor
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- "All NS-guided procedures are guided by (varying) anatomical landmarks and in-depth nerve stimulation, by which the target nerves are only indirectly located by their muscular responses. As such NS-guided blocks have been the standard method for about 30 years, but the application of ultrasound has increased substantially during the last 15 years (Klaastad et al., 2009; Marhofer et al., 2010). Recently, however, the value of stimulation thresholds between 0.3 and 0.5 mA as reliable parameter for extraneural needle tip placement has been challenged in animal studies (Chan et al., 2007; Tsai et al., 2008) and very recently in humans (Bigeleisen et al., 2009). "
ABSTRACT: Background The application of ultrasound (US) in peripheral nerve blocks has increased substantially during the last 15years. However, this technique may have some drawbacks, one of which is the need of a high level of experience of the anaesthesiologist in performing US-guided blocks, a.o. in interpreting the cross-sections displayed in the ultrasound images. Sonoanatomical cross-sections produced by digitized anatomy are easier to understand.European Journal of Pain Supplements 11/2010; 2010(4):303–311. DOI:10.1016/j.eujps.2010.09.005
Conference Paper: Automatic grasp planning in the presence of uncertainty[Show abstract] [Hide abstract]
ABSTRACT: This paper presents a method for automatic planning of robot grasping motions that are insensitive to bounded uncertainties in the object's location. The method exploits the physics of friction to generate all grasp plans that utilize either a squeez-grasp, offset-grasp, or push-grasp motion. All plans that are found will succeed even if the worst-case error occurs. From this space of plans, a plan can be chosen and executed without sensing or feedback. Moreover, executing the motion removes two degrees of uncertainty from the object's position. For simplicity, planar motion of the object during grasping is assumed. The planner has been implemented, and the resulting program has been tested on an industrial manipulator.Robotics and Automation. Proceedings. 1986 IEEE International Conference on; 05/1986