Ultrasound-guided Axillary Block Research Articles

Axillary Brachial Plexus Block Compared with Other Regional Anesthesia Techniques in Distal Upper Limb Surgery: A Systematic Review and Meta-Analysis.

Background: Several regional anesthesia (RA) techniques have been described for distal upper limb surgery. However, the best approach in terms of RA block success rate and safety is not well recognized. Objective: To assess and compare the surgical anesthesia and efficacy of axillary brachial plexus block with other RA techniques for hand and wrist surgery. The attainment of adequate surgical anesthesia 30 min after block placement was considered a primary outcome measure. Additionally, successful block outcomes were required without the use of supplemental local anesthetic injection, systemic opioid analgesia, or the need to convert to general anesthesia. Methods: We performed a systematic search in the following databases: MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and CENTRAL. RCTs comparing axillary blocks with other brachial plexus block techniques, distal peripheral forearm nerve block, intravenous RA, and the wide-awake local anesthesia no tourniquet (WALANT) technique were included. Results: In total, 3070 records were reviewed, of which 28 met the inclusion criteria. The meta-analysis of adequate surgical anesthesia showed no significant difference between ultrasound-guided axillary block and supraclavicular block (RR: 0.94 [0.89, 1.00]; p = 0.06; I2 = 60.00%), but a statistically significant difference between ultrasound-guided axillary block and infraclavicular block (RR: 0.92 [0.88, 0.97]; p < 0.01; I2 = 53.00%). Ultrasound-guided infraclavicular blocks were performed faster than ultrasound-guided axillary blocks (SMD: 0.74 [0.30, 1.17]; p < 0.001; I2 = 85.00%). No differences in performance time between ultrasound-guided axillary and supraclavicular blocks were demonstrated. Additionally, adequate surgical anesthesia onset time was not significantly different between ultrasound-guided block approaches: ultrasound-guided axillary blocks versus ultrasound-guided supraclavicular blocks (SMD: 0.52 [-0.14, 1.17]; p = 0.12; I2 = 86.00%); ultrasound-guided axillary blocks versus ultrasound-guided infraclavicular blocks (SMD: 0.21 [-0.49, 0.91]; p = 0.55; I2 = 92.00%). Conclusions: The RA choice should be individualized depending on the patient, procedure, and operator-specific parameters. Compared to ultrasound-guided supraclavicular and infraclavicular block, ultrasound-guided axillary block may be preferred for patients with significant concerns of block-related side effects/complications. High heterogeneity between studies shows the need for more robust RCTs.

Diabetic Neuropathy and Minimum Effective Anesthetic Concentration of Mepivacaine for Axillary Brachial Plexus Block: A Prospective Observational Study.

Nerves in patients with diabetic neuropathy (DN) show increased susceptibility to local anesthetics, potentially requiring a decreased dose. We investigated whether the minimum effective anesthetic concentration (MEAC) of mepivacaine for successful axillary block is lower in patients with DN than in those without. This prospective observational study included patients with DN (n = 22) and without diabetes (n = 22) at a tertiary care center. Patients received an ultrasound-guided axillary block with 30 mL of mepivacaine for anesthesia. The mepivacaine concentration used in each patient was calculated using Dixon's up-and-down method. A block was considered successful if all four sensory nerves had a score of 1 or 2 within 30 min with no pain during surgery. The primary outcome was the MEAC of mepivacaine, and the secondary outcomes included the minimal nerve stimulation intensity for the musculocutaneous nerve and the occurrence of adverse events. The MEAC50 was 0.55% (95% CI 0.33-0.77%) in patients without diabetes and 0.58% (95% CI 0.39-0.77%) in patients with DN (p = 0.837). The MEAC90 was 0.98% (95% CI 0.54-1.42%) in patients without diabetes and 0.96% (95% CI 0.57-1.35%) in patients with DN (p = 0.949). The stimulation threshold for the musculocutaneous nerve was significantly different between groups (0.49 mA vs. 0.19 mA for patients with vs. without diabetes; p = 0.002). In conclusion, the MEAC of mepivacaine for a successful axillary block is not lower in patients with DN.

Successful Glenohumeral Shoulder Reduction With Combined Suprascapular and Axillary Nerve Block

BackgroundAnterior glenohumeral dislocation is a common injury seen in the emergency department (ED) that sometimes requires procedural sedation for manual reduction. When compared with procedural sedation for dislocation reductions, peripheral nerve blocks provide similar patient satisfaction scores but have shorter ED length of stays. In this case report, we describe the first addition of an ultrasound-guided axillary nerve block to a suprascapular nerve block for reduction of an anterior shoulder dislocation in the ED. Case ReportA 34-year-old man presented to the ED with an acute left shoulder dislocation. The patient was a fit rock climber with developed muscular build and tone. An attempt to reduce the shoulder with peripheral analgesia was unsuccessful. A combined suprascapular and axillary nerve block was performed with 0.5% bupivacaine, allowing appropriate relaxation of the patient's musculature while providing excellent pain control. The shoulder was then successfully reduced without procedural sedation. Why Should an Emergency Physician Be Aware of This?Procedural sedation for reduction of anterior shoulder dislocations is time consuming, resource intensive, and can be risky in some populations. The addition of an axillary nerve block to a suprascapular nerve block allows for more complete muscle relaxation to successfully reduce a shoulder dislocation without procedural sedation.

Perfusion Index Value in Determining the Success of Axillary Block.

To evaluate whether the perfusion index (PI) can be used to predict and provide a cut-off value for ultrasound-guided axillary nerve block success. Quasi-experimental study. Department of Anaesthesiology and Reanimation, Adiyaman University Training and Research Hospital, Adiyaman, Turkey, from July to August 2020. Fifty patients between the ages of 18 and 65 years, who were in the ASA 1-2 group, undergoing hand, wrist and forearm surgery, were included in the study. PI value was measured from the extremity to the block and the healthy extremity before and after the procedure. Sensory block was evaluated with the pin-prick test, Motor block was evaluated with the Modified Bromage Scale. The minutes when sensory and motor blocks occurred were recorded, and the PI value at these moments were recorded. Pin-prick test was positive in patients at average 8.4±2.4 minutes. The average PI value for which the pin-prick test was positive was 7.41±2.54, and the cut-off value of the sensory block PI ratio was determined as 1.7 times. The modified Bromage scale reached a score of 2 in 7.6±2.3 minutes on average. The average PI value is 7.27±2.69 for which the modified Bromage Scale score is 2. At modified Bromage Scale-2, PI ratio cut-off value was determined as 1.7 times. The modified Bromage Scale reached a score of 3 in an average of 12.6±4.2 minutes. The mean PI value for the modified Bromage Scale score of 3 is 9.56±6.97. The motor block PI ratio cut-off value was determined as 1.9 times. Pulse oximetry perfusion index is a sensitive and simple method that can be used to evaluate the success of axillary block. The cut-off value, indicating successful block for the rate of sensory block and modified Bromage scale PI, was determined as 1.7 times and the motor block PI ratio as 1.9 times. Axillary block, Perfusion index, Oximetry, Ultrasonography, Modified bromage scale.

General anesthesia versus ultrasound-guided axillary block for ambulatory hand surgery: randomized prospective study

BackgroundIn upper limb surgery, both axillary brachial plexus block (ABPB) and general anesthesia (GA) have been widely used. ABPB is one of the most popular and widely used procedures for brachial plexus blocks, as well as for achieving upper limb regional anesthesia.The aim of the study was to compare between both anesthetic techniques for ambulatory hand surgery regarding their effects on postoperative pain as primary outcome and postoperative nausea and vomiting and patient satisfaction and postoperative sleep disturbances as secondary outcomes.ResultsWe reviewed data from 40 patients for the primary outcome and found that group A (had general anesthesia) had a statistically significant higher postoperative VAS score than group B (got ultrasound guided axillary block), (P-value 0.05). In terms of secondary outcomes, postoperative nausea and vomiting were significantly higher in group A patients (P-value 0.001), and patient satisfaction was significantly higher in group B patients compared to group A patients (P-value 0.001). Furthermore, the Pittsburgh quality index (PSQI) for postoperative sleep disruptions was considerably higher in group A than in group B at 24 h postoperatively and at the first and second weeks postoperatively (P-value 0.001). Statistically, there is no difference between the two groups in the third week and one month after surgery.ConclusionsWhen compared to general anesthesia, ultrasound-guided axillary brachial plexus block offered good anesthesia, great analgesia, and a better postoperative sleep result after hand surgery.

A randomised, non-inferiority study of chloroprocaine 2% and ropivacaine 0.75% in ultrasound-guided axillary block

Chloroprocaine is a short-acting local anaesthetic with a rapid onset of action and an anaesthesia duration up to 60 min. In this pivotal study success rates, onset and remission of motor and sensory block and safety of chloroprocaine 2% was compared to ropivacaine 0.75% for short-duration distal upper limb surgery with successful block rates as primary outcome. The study was designed as a prospective, randomised, multi-centre, active-controlled, double-blind, parallel-group, non-inferiority study, performed in 4 European hospitals with 211 patients scheduled for short duration distal upper limb surgery under axillary plexus block anaesthesia. Patients received either ultrasound guided axillary block with 20 ml chloroprocaine 2%, or with 20 ml ropivacaine 0.75%. Successful block was defined as block without any supplementation in the first 45 min calculated from the time of readiness for surgery. 90.8% patients achieved a successful block with chloroprocaine 2% and 92.9% patients with Ropivacaine 0.75%, thus non-inferiority was demonstrated (10% non inferiority margin; 95% CI − 0.097, 0.039; p = 0.02). Time to onset of block was not significantly different between the groups. Median time to motor and sensory block regression was significantly shorter as was time to home discharge (164 [155–170] min for chloroprocaine versus 380 [209–450] for the ropivacaine group, p < 0.001). For short-duration surgical procedures, the short-acting Chloroprocaine 2% may be used, with success rates non-inferior to ropivacaine and a favourable safety profile.Trial registration: The trial was registered at Clinicaltrials.gov with registration number NCT02385097 (March 11th, 2015) and European Clinical Trial Database with the EudraCT number 2014-002519-40 (July 7th, 2015, Austria—BASG).

Lateral ultrasound-guided axillary RUMM block in cats: a pilot cadaveric study.

This study aimed to describe the prominent landmarks for an in-plane ultrasound-guided lateral approach to an axillary RUMM block in cats and document the anatomical distribution of injected solution in cadavers. Eleven mixed breed, frozen-thawed cat cadavers were used. The ultrasound probe was placed on the lateral aspect of the forelimb. A spinal needle was used to inject either methylene blue 5 mg/ml or permanent tissue dye 1:10 within the focal clustering point of the radial (R), ulna (U), median (M) and musculocutaneous (Mc) nerves. The block was approached from either a cranial or caudal direction. Specimens were immediately dissected. A successful block was defined as ⩾20 mm of continuous stain on all nerves (R, U, M and Mc), a partial block as one or more nerves stained ⩾20 mm continuously and a negative block failed to stain any nerve ⩾20 mm. The cranial approach stained the R 8/9, U 6/9, M 6/9 and Mc 8/9 nerves successfully, while the caudal approach stained the R 7/9, U 8/9, M 7/9 and Mc 5/9 nerves successfully. There were no statistical differences on staining rates between approaches or limbs used. The lateral approach to an axillary RUMM block is feasible in cats and may be a useful alternative to current approaches used for brachial and antebrachial desensitisation. Both cranial and caudal approaches produced similar results; however, further research in live animals will determine the clinical applicability.

A randomized controlled trial evaluating the impact of selective axillary nerve block after arthroscopic subacromial decompression

BackgroundThe sensory innervation of the shoulder is complex and there are variations in the branching patterns of the sensory fibres. Articular branches from the axillary nerve to the subacromial bursa are described in more than 50% of investigated shoulders but the isolated contribution of sensory input from the axillary nerve has never been investigated clinically.We hypothesized that a selective block of the axillary nerve would reduce morphine consumption and pain after arthroscopic subacromial decompression.MethodsWe included 60 patients in a randomized, blinded, placebo-controlled study. Patients were randomized to a preoperative selective ultrasound-guided axillary nerve block with 20 mL ropivacaine (7.5 mg/mL) or 20 mL saline. Primary outcome was intravenous morphine consumption 0–4 h postoperatively. Secondary outcome was postoperative pain evaluated by a visual analogue scale (VAS) score (0–100).ResultsWe analysed data from 50 patients and found no significant difference in 0–4 h postoperative morphine consumption between the two groups (ropivacaine 14 mg, placebo 18 mg (P = 0.12)). There was a reduction in postoperative pain: VAS 0–4 h (area under the curve) (ropivacaine 135, placebo 182 (P = 0.03)), VAS after 8 h (ropivacaine 9, placebo 20 (P = 0.01)) and VAS after 24 h (ropivacaine 7, placebo 18 (P = 0.04)). Eight out of 19 patients with a successful selective axillary nerve block needed an interscalene brachial plexus escape block.ConclusionsSelective block of the axillary nerve has some pain relieving effect, but in this setting the effect was unpredictable, variable and far from sufficient in a large proportion of the patients.Trial registrationClinicalTrials.gov (NCT01463865). Registered: November 1, 2011.

Locoregional Anesthesia in a Resource-Limited Country: Can Lidocaine 1.5% with Adrenaline Be an Alternative to Ropivacaine 0.5% for Ultrasound-Guided Axillary Blocks?

Background: The ultrasound-guided axillary block is a block commonly used in upper limb surgery. Several local anaesthetics can be used to obtain an effective block. These include ropivacaine 0.5% and lidocaine 1.5% with adrenaline. Objective: To evaluate lidocaine 1.5% with adrenaline as an alternative to ropivacaine 0.5% for ultrasound-guided axillary blocks. Methodology: This was a 6-month prospective and randomized study (July 15, 2019 to January 15, 2020) conducted in the Department of Anesthesia at Ignace Deen National Hospital in Conakry, Guinea. Results: A total of 38 patients were enrolled: 19 in each group. The mean age was 45.8 ± 16.9 years in the lidocaine with adrenaline group compared to 43.9 ± 20 years in the ropivacaine group. The mean onset time in the lidocaine group was 6.8 ± 2.1 minutes compared to 8.3 ± 2.4 minutes in the ropivacaine group (p = 0.04). The mean duration of axillary block was 233.3 ± 57.5 minutes in the lidocaine group versus 260.4 ± 74 minutes in the ropivacaine group (p = 0.21). The performance was identical in both groups with 89.5% of the effective blocks in the lidocaine group and in the ropivacaine group (p = 1). The cost of consumables for the ropivacaine group was 60 euros compared to 15 euros for the lidocaine group. Conclusion: Lidocaine 1.5% with adrenaline is a good alternative to ropivacaine 0.5% for ultrasound-guided axillary blocks in resource-limited countries.

Evaluation of magnesium as an adjuvant to ropivacaine-induced axillary brachial plexus block: A prospective, randomised, double-blind study.

Background and Aims:Axillary brachial plexus block is commonly performed for surgeries on the hand and forearm. However, there are very few studies on the use of magnesium sulphate in axillary brachial plexus block and, hence, the study was designed to evaluate magnesium as an adjuvant to ropivacaine-induced axillary block with respect to onset and duration of sensorimotor block and postoperative analgesia.Methods:Sixty patients of the American Society of Anesthesiologists (ASA) physical status I and II, undergoing surgeries on the hand and forearm were randomly recruited to receive ultrasound-guided axillary block with either 150 mg magnesium sulphate or 1 mL normal saline added to 0.5% ropivacaine. The primary outcome measure was to compare block characteristics including postoperative analgesia and the secondary outcome was to compare the use of rescue analgesia and the side-effect profile. Data were statistically analysed using Statistical Package for Social Sciences (SPSS version 21.0). Categorical variables were compared using the Chi-square test or Fisher's exact probability test; continuous variables compared using unpaired t-test or Mann-Whitney U test.Results:Onset of sensory (9.93 ± 1.31 vs 8.83 ± 1.12 min) as well as motor block (13.37 ± 1.63 vs 11.57 ± 1.30 min) was significantly hastened with addition of magnesium to ropivacaine (p < 0.001) and so was the duration (sensory 386.60 ± 18.26 vs 526.37 ± 27.43, motor 323.73 ± 15.17 vs 436.97 ± 18.99 min) (p < 0.001) and postoperative analgesia (425 ± 21.39 vs 572.83 ± 32.04 min) (p < 0.001) which reflected in decreased requirement of rescue analgesic and total postoperative analgesic dosage.Conclusions:Magnesium is an effective and safe adjuvant to local anaesthetics and improves all characteristics of axillary brachial plexus block along with postoperative analgesia.

Clinical effectiveness of single dose of intravenous dexamethasone on the duration of ropivacaine axillary brachial plexus block: the randomized placebo-controlled ADEXA trial.

The effect of intravenous dexamethasone on the duration of axillary plexus block performed using ropivacaine is not described. The aim of this study is to assess the effect of intravenous dexamethasone on the duration of axillary plexus block analgesia after distal upper arm surgery. In this prospective, randomized, placebo-controlled, double-blinded trial, consenting patients scheduled for hand or forearm surgery under ultrasound-guided axillary plexus block performed using 0.5 mL/kg of 0.475% ropivacaine, were randomized to receive an intravenous injection of either 8 mg/2 mL of dexamethasone (Dexa group) or 2 mL of saline (Control). The primary outcome was the time of first analgesic intake after axillary block. Secondary outcomes included motor or sensory block duration, total use of postoperative analgesics, and block-related complications. Among the 98 patients included, 6 and 2 patients did not require postoperative analgesic intake in Dexa and Control groups, respectively (p=0.06). The time of first analgesic intake was significantly longer in the Dexa (20.9±9.3 hours) than in the Control group (14.7±6.6 hours, p<0.0004). Motor and sensory recovery occurred significantly later, and total analgesic consumption was lower in the Dexa than in the Control group. No nerve complication related to intravenous dexamethasone injection was recorded. This study showed that intravenous dexamethasone delayed for 6 hours the time to first analgesic intake after upper arm surgery under axillary plexus block performed with the long-lasting local anesthetic ropivacaine. This suggests that intravenous dexamethasone could be an interesting adjuvant to axillary plexus block. NCT02862327.

Superficial Venous Dilatation Induced by Ultrasound-Guided Axillary Nerve Block in Vascular Access Surgery.

Objectives: We aim to assess the effect and significance of ultrasound-guided axillary nerve block on the diameter of basilic vein in vascular access surgery.Methods: 78 consecutive patients who underwent vascular access surgery with ultrasound-guided axillary nerve block were studied retrospectively. Diameter of basilic vein at the elbow level before and after the nerve block were measured and the dilatation rate was also calculated to assess the effect of nerve block on venous diameter.Results: Basilic vein diameter increased from 3.0±1.1 mm before the block to 4.1±1.2 mm after the block (p<0.001). Mean dilatation rate was 143±34%. The dilatation rate was inversely correlated with venous diameter before the block (p<0.001).Conclusion: Ultrasound-guided axillary nerve block induces significant basilic venous dilatation and that make the anastomotic procedure involving basilic vein possible, or much easier. This anesthetic technique was considered to be an effective option in vascular access surgery. (This is a translation of Jpn J Vasc Surg 2017; 26: 235–239.)

Ostéosynthèse des fractures du radius distal en mini-open et en WALANT par plaque verrouillée antérieure

The aim of this comparative and prospective study was to evaluate the feasibility and benefits of a mini invasive pronator-sparing technique for radius distal fracture treated with volar locking plate performed with a WALANT anesthesia. Sixty patients (from June 2016–June 2017) with an extra articular fracture of the distal radius and a mean age of sixty two years were managed with a distal volar plate and an in situ catheter for continuous diffusion of Ropivacaine during 48 hours after surgery. There were two groups (30 patients per group). Patients of the first group receive a WALANT anesthesia (Lidocaine 1%, epinephrine 0.05/10 ml). In the second group patients have had an ultrasound guided axillary block and a tourniquet. The following points were monitored: duration of the procedure, need for additional anesthesia or sedation during the surgery, patient discomfort. Pain was evaluated with a visual analog scale at Day 0, Day 1, Day 2, Day 3, Day 7, and Day 45. A clinical and radiological evaluation was made at 6 weeks and 3 months after surgery (range of motion, anatomical alignment and screw placement). The study was approved by our local ethics committee. All the patients were available at the last follow up. In the group I (WALANT) VAS (D0/D1/D2) was significantly lower than in the group II (2.2/3.5/4.9 vs 4.1/4.8/6.2). The were no difference of the results of VAS after Day 2. In the group I no patients received a sedation, while in group II 4 patients required additional analgesia. During the procedure, and only in group II, 2 patients complained about pain at the wrist, 12 of discomfort at the tourniquet and 8 patients were anxious about not knowing where their arms were located. At the last follow up there was no significant difference between the two groups for the duration of the procedure, range of motion and for the anatomical alignment. A reflex sympathetic dystrophy syndrome occurred for 3 patients of the second group. The use of WALANT for open reduction and internal fixation of distal radius fractures allows clinical and anatomical results identical to those obtained with conventional techniques. Moreover, WALANT seems to be a powerful tool for risk management of reflex sympathetic dystrophy syndrome.

Highlighting nerves and blood vessels for ultrasound-guided axillary nerve block procedures using neural networks.

Ultrasound images acquired during axillary nerve block procedures can be difficult to interpret. Highlighting the important structures, such as nerves and blood vessels, may be useful for the training of inexperienced users. A deep convolutional neural network is used to identify the musculocutaneous, median, ulnar, and radial nerves, as well as the blood vessels in ultrasound images. A dataset of 49 subjects is collected and used for training and evaluation of the neural network. Several image augmentations, such as rotation, elastic deformation, shadows, and horizontal flipping, are tested. The neural network is evaluated using cross validation. The results showed that the blood vessels were the easiest to detect with a precision and recall above 0.8. Among the nerves, the median and ulnar nerves were the easiest to detect with an -score of 0.73 and 0.62, respectively. The radial nerve was the hardest to detect with an -score of 0.39. Image augmentations proved effective, increasing -score by as much as 0.13. A Wilcoxon signed-rank test showed that the improvement from rotation, shadow, and elastic deformation augmentations were significant and the combination of all augmentations gave the best result. The results are promising; however, there is more work to be done, as the precision and recall are still too low. A larger dataset is most likely needed to improve accuracy, in combination with anatomical and temporal models.

Patterns of Distribution of the Nerves Around the Axillary Artery Evaluated by Ultrasound and Assessed by Nerve Stimulation During Axillary Block.

Our objective was to define the positions of the nerves around the brachial artery and, secondarily, to assess the risk of intraneural injection during dual guided axillary block. Sixty ultrasound-guided axillary blocks were performed. The locations of the musculocutaneous, median, ulnar, and radial nerves relative to the brachial artery were determined. The position of the ulnar nerve was defined in relation to that of the brachial vein, and the position of the musculocutaneous nerve in relation to the coracobrachialis muscle. The locations were confirmed by neurostimulation and injection of local anesthetic was avoided when the current intensities were below 0.3 mA. The incidences of intraneural injection and postblock neurological injury were recorded. The median nerve was located in the upper external quadrant in 89% of cases and the ulnar nerve in the upper internal quadrant (95%), superficial (19%), or deep (81%) to the brachial vein. The radial nerve was located in the lower internal quadrant in 97% of cases, and the musculocutaneous nerve in the lower external quadrant in 85%. Its disposition differed depending on its proximity to the artery (106 ± 26°) or whether it was inside the coracobrachialis muscle (119 ± 15°; P = 0.023). Three intraneural injections were observed (0.5%, one in the median and two in the radial nerves) and no patient had postblock neuropathy. Our study evidences slight anatomical variability among the neural structures in the axillary region and confirms the safety of the axillary technique with double monitoring, using ultrasound to monitor the approach of the needle to the nerve and nerve stimulation at currents > 0.3 mA to reduce the incidence of intraneural injection. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc. 2018.

Dexmedetomidine as an adjuvant to 0.5% ropivacaine in ultrasound-guided axillary brachial plexus block.

The aim of this study was to elucidate the effect of dexmedetomidine added to ropivacaine on the onset and duration of sensory and motor block and duration of analgesia of ultrasound-guided axillary brachial plexus block. Thirty-seven ASA physical status I-II patients with elective forearm and hand surgery under ultrasound-guided axillary brachial plexus block were randomly divided into 2 groups. Patients in ropivacaine-dexmedetomidine group (group RD, n=19) received 15mL of 0.5% ropivacaine with 100μg (1mL) dexmedetomidine, and patients in ropivacaine group (group R, n=18) received 15mL of 0.5% ropivacaine with 1mL of normal saline. Onset time and duration of sensory and motor block and duration of analgesia were assessed. Duration of sensory block (U-value=35, P<.001), duration of motor block (P=.001) and duration of analgesia (P<.001) were extended in group RD compared to group R. Onset time of sensory block in group RD was significantly faster than in group R (U-value=65.5, P=.001). Onset time of motor block showed no significant difference between the 2 groups (U-value=116.5, P=.096). Adverse reactions were reported only in group RD (bradycardia in 2 and hypotension in 3 patients). Our study indicated that dexmedetomidine 100μg as adjuvant on ultrasound-guided axillary plexus block significantly prolonged the duration of sensory block and analgesia, as well as accelerated the time to onset of sensory block. These results should be weighed against the increased risks of motor block prolongation, transient bradycardia and hypotension and allow for attentive optimism, only if prolonged clinical trials provide a definitive answer.

A Randomized Comparison Between Intravenous and Perineural Dexamethasone for Ultrasound-Guided Axillary Block

(Abstracted from Can J Anaesth, 64(1):29–36, 2017) The purpose of this randomized trial was to compare intravenous (IV) and perineural (PN) dexamethasone in the axillary approach to the brachial plexus. The primary outcome recorded was the duration of the ultrasound (US)–guided axillary motor block (AXB) rather than sensory blockade, which can be influenced by drugs and nerve trauma.

The effect of meperidine on lidocaine-induced axillary block in patients undergoing upper extremities surgery

Background: The increasing use of regional anesthesia and peripheral nervous blocks and also local anesthetic effects of meperidine, made us adding this drug to lidocaine-induced axillary block for patients undergoing upper extremities surgery to measure its effects and especially block length time. Objective: The aim of this study is effect survey of meperidine on lidocaine-induced axillary block in patients undergoing upper extremities surgery. Materials and Methods: This randomized double-blinded clinical trial was conducted on consecutive forty patients aged between 15 and 56 years, rated as the American Society of Anesthesiology I-II who were scheduled for upper extremities surgery. The study protocol was approved by the ethics committee at Kermanshah University of Medical Sciences. These 40 patients divided into two groups which were similar in terms of age, gender, and weight. The patients were randomly assigned to receive one of the two following protocols for axillary block: (1) 40 ml lidocaine 1% plus 0.01 ml/kg normal saline and (2) 40 ml lidocaine 1% plus 0.01 ml/kg equaling 1 mg/kg meperidine. The blocking method was similar in both groups (Ultrasound-Guided Axillary block). The analysis was done with Chi-square and Fisher's exact test for complications and t-test for quantitative variables in both groups. Results: Both two groups were similar in terms of block onset time, the intensity of analgesia block and side effects such as nausea, vomiting, hypotension, dizziness, arrhythmia, and convulsion. The obtained results from this study suggest that meperidine added to lidocaine-induced axillary block prolongs the duration of blocked (238 ± 67.04 vs. 166.7 ± 39.6) which is statistically significant (P

Effect of warming bupivacaine 0.5% on ultrasound-guided axillary plexus block. Randomized prospective double-blind study

ObjectiveTo evaluate the effect of warming bupivacaine 0.5% on ultrasound-guided axillary brachial plexus block. Study designProspective, randomized, double-blind. Patients and methodsEighty patients undergoing elective or emergency surgery beyond the distal third of the upper limb were divided into two groups of 40 patients: the warm group received 15mL bupivacaine 0.5% heated to 37°C; the cold group received 15mL 0.5% bupivacaine stored for at least 24hours in the lower compartment of a refrigerator at 13–15°C. Onset and duration of sensory and motor blocks were evaluated every 5minutes for 40minutes. Postoperative pain was evaluated at 1, 3, 6, 12 and 24hours. Effective analgesia time was recorded as the interval between anesthetic injection and the first analgesia requirement (VAS>30mm). ResultsTime to onset of sensory and motor block was significantly shorter in the warm group, and mean duration of sensory and motor block and of postoperative analgesia significantly longer. ConclusionWarming bupivacaine 0.5% to 37°C accelerated onset of sensory and motor block and extended action duration.

A randomized comparison between intravenous and perineural dexamethasone for ultrasound-guided axillary block

This randomized double-blinded trial compared the effect of intravenous and perineural dexamethasone (8mg) on the duration of motor block for ultrasound (US)-guided axillary brachial plexus block (AXB). Patients undergoing upper limb surgery with US-guided AXB were randomly allocated to receive preservative-free dexamethasone (8mg) via intravenous (n=75) or perineural (n=75) administration. The local anesthetic agent, 1% lidocaine -0.25% bupivacaine (30mL) with epinephrine 5µg·mL-1, was identical in all subjects. Operators and patients were blinded to the nature of the intravenous and perineural injectate. A blinded observer assessed the block success rate (i.e., a minimal sensorimotor composite score of 14 out of 16 points at 30min), block onset time, as well as the presence of surgical anesthesia. Postoperatively, the blinded observer contacted all patients with successful blocks to record the duration of motor block (primary outcome), sensory block, and postoperative analgesia. No intergroup differences were observed in terms of success rate, surgical anesthesia, and block onset time. Compared to intravenous administration, perineural dexamethasone provided longer mean (SD) durations for motor block [17.5 (4.6) hr vs 12.8 (4.5) hr; mean difference, 4.6 hr; 95% confidence interval [CI], -6.21 to -3.08; P<0.001], sensory block [17.7 (5.1) hr vs 13.7 (5.0) hr; mean difference, 4.0 hr; 95% CI, -5.77 to -2.27; P<0.001], and postoperative analgesia [21.1 (4.6) hr vs 17.1 (4.6) hr; mean difference, 4.0 hr; 95% CI, -5.70 to -2.30; P<0.001]. Compared to intravenous dosing, perineural dexamethasone (8mg) results in longer durations of sensorimotor block and postoperative analgesia for ultrasound-guided axillary block. This trial was registered at www.clinicaltrials.gov number, NCT02629835.