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.
"Ultrasound allows a direct visualization of various peripheral nerves and localization of the local anesthetics. This may increase the success rate, decrease performance time and reduce the volume of local anesthetics [50,51]. However, further studies are needed to clarify the issue if ultrasound guidance could actually reduce the risk of nerve injury. "
[Show abstract][Hide abstract] ABSTRACT: Brachial plexus injury is a potential complication of a brachial plexus block or vessel puncture. It results from direct needle trauma, neurotoxicity of injection agents and hematoma formation. The neurological presentation may range from minor transient pain to severe sensory disturbance or motor loss with poor recovery. The management includes conservative treatment and surgical exploration. Especially if a hematoma forms, it should be removed promptly. Comprehensive knowledge of anatomy and adept skills are crucial to avoid nerve injuries. Whenever possible, the patient should not be heavily sedated and should be encouraged to immediately inform the doctor of any experience of numbness/paresthesia during the nerve block or vessel puncture.
The Korean journal of pain 07/2014; 27(3):210-8. DOI:10.3344/kjp.2014.27.3.210
"Ultrasound guided regional anesthesia with conventional block needles may be difficult due to conventional needle tips are non-echogenic. Owing to technological improvements of needle visualization new echogenic needles are started to be used in clinical practice 3, 5, 6. Despite some studies comparing echogenic and non-echogenic needles, according to our review of literature it could not be found any study which compares echogenic, non-echogenic needles and nerve stimulator assistance together in a clinical study on the basis of operation outcomes such as block quality, performing time, pain and satisfaction scores. "
[Show abstract][Hide abstract] ABSTRACT: Objective: In this study we aimed to compare the echogenic needles and the nerve stimulation addition to non-echogenic needles in ultrasound guided axillary brachial plexus block for upper extremity surgery.
Methods: 90 patients were enrolled to the study. The patients were allocated into three groups randomly: Group E (n=30): ultrasound guided axillary block using echogenic needle, Group N (n=30): ultrasound guided axillary block using non-echogenic needle, Group NS (n=30): ultrasound guided axillary block using non-echogenic needle with nerve stimulator assistance. Duration of block procedure, mean arterial pressure, heart rate, pulse-oximetry, onset time of sensory and motor block, duration of sensory and motor block, time to first analgesic use, total need for analgesics, postoperative pain scores, patient and surgeon satisfaction scores were recorded.
Results: Duration of block procedure values were lower in group E and NS, sensory and motor block durations, were significantly lower in group N. Sensorial and motor block onset time values were found lower in group NS but higher in group N. Patient and surgeon satisfaction scores were found lower in group N.
Conclusion: We conclude that ultrasound guided axillary block may be performed successfully using both echogenic needles and nerve stimulation assisted non-echogenic needles.
International journal of medical sciences 07/2013; 10(9):1108-12. DOI:10.7150/ijms.6598 · 2.00 Impact Factor
"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). "
[Show abstract][Hide abstract] ABSTRACT: To determine if the use of needle enhancing software facilitate injection technique in ultrasound-guided peripheral nerve blocks.
Prospective, blinded, randomized controlled trial.
Eight hind limbs from canine cadavers.
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.
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).
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.
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