Fentanyl improves analgesia but prolongs the onset of axillary brachial plexus block by peripheral mechanism

We evaluated the effects of fentanyl added to lidocaine for axillary brachial plexus block in 66 adult patients scheduled for elective hand and forearm surgery. In this double-blinded study, all patients received 40 mL of 1.5% lidocaine with 1:200,000 epinephrine, injected into the brachial plexus sheath using the axillary perivascular technique, and they were randomized into three groups. Group 1 was given lidocaine containing 2 mL of normal saline plus 2 mL of normal saline IV. Patients in Group 2 received lidocaine containing 100 microg fentanyl plus 2 mL of normal saline IV. Group 3 patients received lidocaine containing 2 mL of normal saline plus 100 microg fentanyl IV. Sensory and motor blockade were evaluated by using a pinprick technique and by measuring the gripping force, respectively. The success rate of sensory blockade for radial and musculocutaneous nerves and the duration of the sensory blockade significantly increased in Group 2 (323 +/- 96 min) as compared with Group 1 (250 +/- 79 min). However, onset time of analgesia was prolonged in every nerve distribution by adding fentanyl to brachial plexus block. IV fentanyl had no effect on the success rate, onset, or duration of blockade. We conclude that the addition of fentanyl to lidocaine causes an improved success rate of sensory blockade but a delayed onset of analgesia, although this may be accounted for by the decreased pH caused by the fentanyl. Implications: It is still unclear whether the addition of a peripheral opioid is useful for nerve blockade in humans. Peripheral application of fentanyl to lidocaine for axillary brachial plexus blockade in this study provided an improved success rate of sensory blockade and prolonged duration.     

Sufentanil does not prolong the duration of analgesia in a mepivacaine brachial plexus block: a dose response study

To date, results of studies evaluating the efficacy of opioids and local anesthetic combinations in the brachial plexus are inconclusive. We examined whether increasing sufentanil in doses of 5, 10, and 20 microg decreased onset time or increased duration of an axillary brachial plexus block. Ninety-two patients scheduled for carpal tunnel release under axillary brachial plexus block were enrolled in the study. Patients were randomized to receive axillary plexus block with 40 mL 1.5% mepivacaine and saline (Group 1), sufentanil 5 microg (Group 2), 10 microg (Group 3), or 20 microg (Group 4). Onset and duration of sensory and motor block were measured. Opioid-related side effects were recorded. The addition of sufentanil did not improve speed of onset or increase the duration of sensory or motor block. Paradoxically, duration of sensory and motor block was longest in the control group: sensory, 241 min (188-284) and motor, 234 min (128-305), and decreased with increasing doses of sufentanil in Group 4: sensory, 216 min (115-315) and motor, 172 min (115-260) (P < 0.05). Side effects occurred in 55% of patients belonging to Groups 2 and 4, and in 60% of the patients in Group 3. In contrast, only 10% of the patients reported side effects in the control group. We conclude that sufentanil added to mepivacaine does not increase the onset or prolong the duration of an axillary plexus block. Furthermore, the addition of sufentanil was associated with a frequent incidence of side effects. IMPLICATIONS: This study demonstrates that the addition of sufentanil in a dose-dependent manner to 1.5% mepivacaine in the axillary plexus does not improve onset or duration of blockade, and that this admixture is associated with an increased incidence of side effects.     

Levobupivacaina,bupivacaina racemica e ropivacaina nel blocco del plesso brachiale

BACKGROUND: To compare clinical profiles of levobupivacaine, racemic bupivacaine and ropivacaine at equipotent doses in axillary brachial plexus block in the orthopaedic surgery of wrist and hand. METHODS: For this prospective, open randomised study we took on 45 patients of both sexes, ASA I-III, subdivided into three groups in which, respectively, axillary brachial plexus block was performed, with ENS, using levobupivacaine 0.50% (1 mg/kg), racemic bupivacaine 0.50% (1 mg/kg) and ropivacaine 0.75% (1.4 mg/kg). The onset of sensory and motor block, their duration, onset of surgical block, anaesthetic plane and possible adverse events were recorded. RESULTS: The duration of sensory block was longer in group of patients treated with levobupivacaine than in two other groups. Surgical onset was similar for levobupivacaine and ropivacaine, but it was delayed for racemic bupivacaine. In group of patients who received racemic bupivacaine, two episodes of reduction in heart rate without significant hypotension have been observed. The anaesthetic plan was satisfactory in the all three groups of patients. CONCLUSIONS: In our experience levobupivacaine has been demonstrated to be a good substitute for racemic bupivacaine. Compared to ropivacaine, levobupivacaine induces a longer duration of postsurgery analgesia and, in our opinion, this datum seems to be the most significant.     

Interscalene brachial plexus anesthesia and analgesia for open shoulder surgery: a randomized,double-blinded comparison between levobupivacaine and ropivacaine

We compared the onset time and quality of interscalene brachial plexus block produced with levobupivacaine and ropivacaine in 50 patients undergoing open shoulder surgery randomly allocated to receive 30 mL of 0.5% levobupivacaine (n = 25) or 0.5% ropivacaine (n = 25) injected through a 20-gauge catheter placed into the interscalene sheath using a 18-gauge insulated and stimulating Tuohy introducer. The block was also prolonged after surgery using a patient-controlled interscalene analgesia with 0.125% levobupivacaine or 0.2% ropivacaine, respectively (basal infusion rate, 6 mL/h; bolus, 2 mL; lockout period, 15 min; maximum boluses per hour, three). Three patients (two with levobupivacaine [8%] and one with ropivacaine [4%]) failed to achieve surgical block within 45 min after the injection and were excluded. The onset time of surgical block was 20 min (10-40 min) with levobupivacaine and 20 min (5-45 min) with ropivacaine (P = 0.53). Rescue intraoperative analgesia (0.1 mg of fentanyl IV) was required in eight patients in each group (34%) (P = 0.99). Forty-two patients completed the 24-h postoperative infusion (22 with levobupivacaine and 20 with ropivacaine). Postoperative analgesia was similarly effective in both groups. Total consumption of local anesthetic infused during the first 24 h was 147 mL (144-196 mL) with levobupivacaine and 162 mL (144-248 mL) with ropivacaine (P = 0.019), with a ratio between boluses received and requested of 0.8 (0.4-1.0) and 0.7 (0.4-1.0), respectively (P = 0.004). The degree of motor block of the operated limb was deeper with levobupivacaine than ropivacaine when starting postoperative analgesia; however, no further differences in degree of motor function were observed between the two groups. We conclude that 30 mL of levobupivacaine 0.5% induces an interscalene brachial plexus anesthesia of similar onset and intensity as the one produced by the same volume and concentration of ropivacaine. Postoperative interscalene analgesia with 0.125% levobupivacaine results in similar pain relief and recovery of motor function with less volume of local anesthetic than with 0.2% ropivacaine. IMPLICATIONS: This prospective, randomized, double-blinded study demonstrates that 30 mL of 0.5% levobupivacaine produces an interscalene brachial plexus block of similar onset and quality as the one produced by the same volume of 0.5% ropivacaine. When prolonging the block after surgery, 0.125% levobupivacaine provides adequate pain relief and recovery of motor function after open shoulder surgery, with less volume infused during the first 24 h after surgery than 0.2% ropivacaine.     

Dexamethasone added to lidocaine prolongs axillary brachial plexus blockade

Different additives have been used to prolong regional blockade. We designed a prospective, randomized, double-blind study to evaluate the effect of dexamethasone added to lidocaine on the onset and duration of axillary brachial plexus block. Sixty patients scheduled for elective hand and forearm surgery under axillary brachial plexus block were randomly allocated to receive either 34 mL lidocaine 1.5% with 2 mL of isotonic saline chloride (control group, n = 30) or 34 mL lidocaine 1.5% with 2 mL of dexamethasone (8 mg) (dexamethasone group, n = 30). Neither epinephrine nor bicarbonate was added to the treatment mixture. We used a nerve stimulator and multiple stimulations technique in all of the patients. After performance of the block, sensory and motor blockade of radial, median, musculocutaneous, and ulnar nerves were recorded at 5, 15, and 30 min. The onset time of the sensory and motor blockade was defined as the time between last injection and the total abolition of the pinprick response and complete paralysis. The duration of sensory and motor blocks were considered as the time interval between the administration of the local anesthetic and the first postoperative pain and complete recovery of motor functions. Sixteen patients were excluded because of unsuccessful blockade. The duration of surgery and the onset times of sensory and motor block were similar in the two groups. The duration of sensory (242 +/- 76 versus 98 +/- 33 min) and motor (310 +/- 81 versus 130 +/- 31 min) blockade were significantly longer in the dexamethasone than in the control group (P < 0.01). We conclude that the addition of dexamethasone to lidocaine 1.5% solution in axillary brachial plexus block prolongs the duration of sensory and motor blockade.     

High-dose bupivacaine, levobupivacaine and ropivacaine in axillary brachial plexus block

BACKGROUND: Racemic bupivacaine is clinically similar to levobupivacaine, or ropivacaine. The drugs were compared in brachial plexus block for the first time in the same randomized and double-blind study. METHODS: In 90 patients scheduled for hand and forearm surgery, a perivascular axillary brachial plexus block was performed with 45 ml of 5 mg ml(-1) of either racemic bupivacaine-HCl, levobupivacaine-HCl, or ropivacaine-HCl. Sensory (cold) and motor (hand clasp, and movement of elbow) block were scored, and the patient was interviewed in the postoperative evening and the following morning. Time to normal function of the arm was registered. RESULTS: After similar onsets of sensory block, the sum of completely anaesthetized innervation areas of the four main nerves at 45 min was greater in the ropivacaine group than in the levobupivacaine group (P < 0.01). Simultaneously, complete motor block at the elbow was more frequent in the ropivacaine group (67%) than in the bupivacaine (47%) and levobupivacaine groups (30%) (P < 0.01). In the hand, the corresponding results were 83%, 77%, and 57%, respectively (NS). Two patients in the levobupivacaine and one in the ropivacaine group needed general anaesthesia. Mean duration of the blocks was similar in the bupivacaine, levobupivacaine and ropivacaine groups at 19.3 h, 19.5 h, and 17.3 h, respectively (NS). Two patients were dissatisfied with the long block duration. CONCLUSION: Ropivacaine-HCl 5 mg ml(-1) produced slightly better sensory and motor block intensity than the same dose of levobupivacaine-HCl. General success in relation to surgery and in the duration of the blocks was similar in the three groups.     

Addition of fentanyl to bupivacaine prolongs anesthesia and analgesia in axillary brachial plexus block

BACKGROUND AND OBJECTIVES: To evaluate the analgesic and anesthetic effects of 40 mL bupivacaine 0.25%, 40 mL bupivacaine 0.25% plus fentanyl 2.5 microg/mL, and 40 mL bupivacaine 0.125% plus fentanyl 2.5 microg/mL for axillary brachial plexus block. METHODS: Sixty patients were randomly allocated to 3 groups and received axillary brachial plexus block with 40 mL bupivacaine 0.25% (group B), 40 mL bupivacaine 0.25% with fentanyl 2.5 microg/mL (group BF), or 40 mL bupivacaine 0.125% with fentanyl 2.5 microg/mL (group DBF). The onset times and the duration of sensory and motor blocks, duration of analgesia, hemodynamic parameters, and adverse events were noted. RESULTS: The mean duration of sensory block and analgesia were longer in group BF (10.1 hours and 20.9 hours) than group B (6.9 hours and 11.6 hours) and DBF (5.9 hours and 12.0 hours) (P < .01, P < .001, respectively). The mean duration of motor block was also longer in group BF (10.7 hours) than group B (4.9 hours) (P < .01). Only 2 patients experienced motor block in group DBF. The frequency of successful block was 35% in group DBF (P < .01). Hemodynamic parameters were similar in all groups. In group B, only 1 patient experienced dizziness. Nausea was observed in 1 patient in each fentanyl group. CONCLUSION: The addition of 100 microg/mL fentanyl to 0.25% bupivacaine almost doubles the duration of analgesia following axillary brachial plexus block when compared with 0.25% bupivacaine alone.     

Brachial plexus block with midazolam and bupivacaine improves analgesia

PURPOSE: Adjuncts to local anesthetics for brachial plexus block may enhance the quality and duration of analgesia. Midazolam, a water-soluble benzodiazepine, is known to produce antinociception and enhance the effect of local anesthetics when given epidurally or intrathecally. The purpose of this study was to assess the effect of midazolam added to brachial plexus anesthesia. METHODS: A prospective, randomized, double blind study was conducted on 40 ASA I or II adult patients undergoing upper limb surgeries under supraclavicular brachial plexus block. Patients were randomly divided into two groups. Patients in Group B (n = 20) were administered 30 mL of 0.5% bupivacaine and Group BM (n = 20) were given 30 mL of 0.5% bupivacaine with midazolam 50 microg x kg(-1). Hemodynamic variables (i.e., heart rate, noninvasive blood pressure), pain scores and rescue analgesic requirements were recorded for 24 hr postoperatively. RESULTS: The onset of sensory and motor block was significantly faster in Group BM compared to Group B (P < 0.05). Pain scores were significantly higher in Group B compared to Group BM from two hours to 24 hr postoperatively (P < 0.05). Rescue analgesic requirements were significantly less in Group BM compared to Group B (P < 0.05). Hemodynamics and sedation scores did not differ between groups in the post-operative period. CONCLUSION: Midazolam (50 microg x kg(-1)) in combination with 30 mL of bupivacaine (0.5%) hastened onset of sensory and motor block, and improved postoperative analgesia when used in brachial plexus block, without producing any adverse events.     

A comparison of 1% prilocaine with 0.5% ropivacaine for outpatient-based surgery under axillary brachial plexus block.

We compared the use of 1% prilocaine with 0.5% ropivacaine for axillary brachial plexus anesthesia in a double-blinded manner in day-stay patients to determine the better of the two local anesthetics in terms of onset time and duration of motor block. Sixty patients scheduled for outpatient upper-limb surgery were allocated randomly to receive either prilocaine (28 patients) or ropivacaine (32 patients) at a volume of 0.7 mL/kg. The brachial plexus was located with a plexus needle and nerve stimulator. By 20 min after injection of prilocaine or ropivacaine, there was no difference in analgesic effect. By this time, it was apparent whether or not a block was going to be adequate for surgery. Pain returned after a mean of 278 min (SD 111 min; range, 160-630 min) with prilocaine as compared with 636 min (SD 284 min; range, 210-1440 min) with ropivacaine. Analgesia use was similar in both groups. Duration of motor block with prilocaine was a mean of 254 min (SD 62 min; range, 130-385 min), as compared with 642 min (SD 199 min; range, 350-1080 min) with ropivacaine. We conclude that there is no clinically important difference between 1% prilocaine and 0.5% ropivacaine in time to onset of axillary brachial plexus block when they are injected in equal volumes. There is a significantly longer duration of action with ropivacaine, which may make it less suitable for day-stay upper-limb surgery because of the handicap from reduced muscle power. Implications: This study compares two local anesthetics to determine which is most suitable for day-stay upper-limb surgery under axillary brachial plexus block.Prilocaine 1% is more suitable than ropivacaine 0.5% because of a more prolonged duration of action of ropivacaine, although this could be useful in other circumstances.     

High doses of mepivacaine for brachial plexus block in patients with end-stage chronic renal failure. A pilot study

BACKGROUND AND OBJECTIVE: Patients with end-stage chronic renal failure are at risk of developing several serious postanaesthetic complications. Many anaesthesiologists perform brachial plexus anaesthesia with high doses of local anaesthetic in order to achieve an extensive blockade of the upper limb. Brachial plexus block is a suitable technique for anaesthesia for creation, repair or removal of vascular access for haemodialysis. The aim of this study was to measure mepivacaine plasma concentrations after axillary block with 650 mg plain mepivacaine in patients with end-stage chronic renal failure. METHODS: Mepivacaine plasma concentrations were assessed throughout a 150-min period, in 10 patients after axillary block with 650 mg plain mepivacaine (600 mg for axillary block and 50 mg for supplementation). RESULTS: Mepivacaine plasma concentrations expressed in microg mL(-1) as medians and their ranges were: 1.69 (1.23--7.78) at 5 min, 5.61 (4.36--8.19) at 30 min, 8.28 (3.83--11.21) at 60 min, 7.93 (5.63--11.1) at 90 min and 6.49 (5.56--8.35) at 150 min without any symptoms of toxicity. CONCLUSIONS: Brachial plexus anaesthesia with 650 mg plain mepivacaine did not result in serious systemic toxicity in these patients despite the high mepivacaine plasma concentrations found.     

Brachial plexus block with levobupivacaine at the humeral canal: comparison of a small volume at high concentration with a large volume at low concentration

OBJECTIVE: To assess differences in the brachial plexus block in 2 groups who received the same dose of levobupivacaine: 1 group received a small volume of solution at high concentration and the other group received a large volume in solution at low concentration. MATERIAL AND METHODS: A prospective, randomized clinical trial enrolling 69 patients scheduled for wrist and/or hand surgery with a brachial plexus block with levobupivacaine in the humeral canal. Nerve stimulation was used to locate a response from the 4 terminal nerves in the brachial plexus. In the group receiving a larger volume, 10 mL of a solution of levobupivacaine at a concentration of 0.375% was used for each nerve. In the high concentration group receiving a smaller volume, levobupivacaine was used at a concentration of 0.75% in 5 mL for each nerve. Sensory latency was assessed by the pin prick technique. Motor block, the success rate (percentage), and duration of sensory and motor blockades were also evaluated. RESULTS: The full sensory block was significantly more efficacious in the large volume group than in the high concentration group (85.3% vs 51.6%, P = 0.003). A full motor block was reached in a small percentage of patients in both groups. There were no significant differences in latency or duration of block. CONCLUSIONS: The success rate was lower in the group receiving the smaller volume at a higher concentration. It is advisable to administer local anesthetics in larger volumes at lower concentrations to improve block quality. Latency and duration were similar in both groups.     

Clonidine prolongs the effect of ropivacaine for axillary brachial plexus blockade

PURPOSE: To evaluate the effect of adding clonidine to ropivacaine, for axillary brachial plexus blockade, on the onset and duration of sensory and motor block and duration of analgesia. METHODS: In a prospective randomised double blind placebo controlled study axillary brachial plexus blockade was performed in 50 patients using 40 ml ropivacaine 0.75%. Group (A) had 150 microg clonidine and Group (B) 1 ml normal saline added to the local anesthetic. Sensory function was tested using pinprick (sharp sensation, blunt sensation or no sensation) and temperature with an ice cube compared with the opposite arm, (cold/not cold). Motor function was assessed using a modified Bromage scale. Postoperative analgesia was standardised. Onset and duration of sensory and motor blockade, duration of analgesia, postoperative pain score, and analgesic requirement were compared. RESULTS: The clonidine patients showed an increase in duration of sensory loss from 489 min to 628 min with a mean difference of 138 min (95% confidence interval of 90 to 187 min), motor blockade from 552 min to 721 min with a mean difference of 170 min (95% confidence interval of 117 to 222 min), and analgesia from 587 min to 828 min with mean difference of 241 min (95% confidence interval of 188 to 294 min). There was no difference in onset time. No side effects were noted. CONCLUSION: The addition of 150 microg of clonidine to ropivacaine, for brachial plexus blockade, prolongs motor and sensory block and analgesia, without an increased incidence of side effects.     

右美托咪定对左旋布比卡因腋路臂丛神经阻滞的影响

目的观察右美托咪定对左旋布比卡因腋路臂丛神经阻滞的影响。方法 50例ASAⅠ或Ⅱ级需于腋路臂丛神经阻滞下行前臂或手部手术的患者随机均分为两组,分别以40ml0.5%左旋布比卡因联合1ml(100μg)右美托咪定(LD组)和1ml等渗氯化钠(LS组)行腋路臂丛神经阻滞,比较两组感觉和运动阻滞起效时间、持续时间、镇痛时间以及HR、MAP、SpO2等。结果感觉和运动阻滞起效时间LD组明显短于LS组(P<0.05),感觉和运动阻滞持续时间LD组明显长于LS组(P<0.05),镇痛时间LD组长于LS组(P<0.05)。MAP在给药后的15、30、45、60、90和120minLD组较LS组显著下降(P<0.05),HR在给药后所有时点LD组均显著慢于LS组(P<0.05)。结论右美托咪定100μg联合左旋布比卡因在腋路臂丛神经阻滞中可以缩短其感觉和运动阻滞起效时间,延长阻滞持续时间及镇痛时间,但可能导致心动过缓。     

Addition of sodium bicarbonate and/or clonidine to mepivacaine: influence on axillary brachial plexus block characteristics

BACKGROUND AND OBJECTIVE: The axillary brachial plexus block is a frequently performed anesthetic technique. Adding a variety of coadjuvant drugs has been shown to improve results. This study evaluated the addition of sodium bicarbonate (NaHCO3) and/or clonidine to mepivacaine for performing the block. MATERIAL AND METHODS: Sixty patients between 18 and 70 years old, ASA 1-3 in stable condition received axillary brachial plexus blocks in a randomized controlled study. Four groups of 15 patients each were formed: group I (control group) received 40 mL of 1% mepivacaine with adrenaline plus 5 mL of saline; group II, 40 mL of 1% mepivacaine with adrenaline plus 4 mL of NaHCO3 and 1 mL of saline; group III, 40 mL of 1% mepivacaine with 150 microg of clonidine plus 4mL of saline; and group IV, 40 mL of 1% mepivacaine with adrenaline plus 4 mL of NaHCO3 and 150 microg of clonidine. RESULTS: The onset time was significantly shorter in groups 2 and 4. The duration of the block was longer in group 3 and the analgesic effect was significantly better. CONCLUSIONS: Adding NaHCO3 to mepivacaine shortens the time of onset of an axillary brachial plexus block. Including clonidine prolongs the duration of anesthesia and analgesia. The addition of both NaHCO3 and clonidine shortens time to onset but does not prolong duration of anesthesia or analgesia.     

Clonidine combined with a long acting local anesthetic does not prolong postoperative analgesia after brachial plexus block but does induce hemodynamic changes

Clonidine in brachial plexus block prolongs analgesia of local anesthetics of short and intermediate duration. We performed a prospective randomized double-blinded study to determine the efficacy and adverse effects of clonidine mixed with a long-acting local anesthetic on postoperative analgesia. Sixty adult patients underwent elective rotator cuff repair using interscalene brachial plexus block combined with general anesthesia and were randomly divided into one of the following three groups. Placebo (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine (1/200000) and 1 mL of 0.9% saline, completed by 1 mL of 0.9% saline IM in the controlateral shoulder; Control (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine and 1 mL of 0. 9% saline, completed by 150 microg (=1 mL) of clonidine IM; Clonidine (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine and 150 microg (=1 mL) of clonidine, completed by 1 mL of 0.9% saline IM. During anesthesia hemodynamic variables and fractional expired isoflurane concentration (FeISO) were recorded. The following postoperative variables were assessed: duration of interscalene block, quality of pain relief on a visual analog scale, side effects, and consumption of morphine with a patient-controlled analgesia device over 48 h. Patient characteristics were comparable. During anesthesia mean arterial pressure, heart rate, and FeISO were significantly decreased in Clonidine and Control groups compared with Placebo group. Duration of analgesia, defined as the time elapsed from interscalene injection to the first morphine request, was 983 +/- 489 min in the Placebo, 909 +/- 160 min in the Control, and 829 +/- 159 min in the Clonidine groups. Pain scores and consumption of morphine at 24 h and 48 h showed no differences among the three groups. We conclude that adding 150 microg of clonidine in interscalene block does not prolong analgesia induced by 40 mL of bupivacaine 0.5% with epinephrine, but decreases mean arterial blood pressure and heart rate. Implications: Clonidine in brachial plexus block does not improve postoperative analgesia when mixed with a long-lasting anesthetic. Nevertheless, with or without clonidine, bupivacaine in interscalene block provides a long-lasting analgesia of approximately 15 h.     

Four-injection brachial plexus block using peripheral nerve stimulator: a comparison between axillary and humeral approaches

We conducted this prospective, randomized study to compare the success rate, performance time, and onset time of surgical anesthesia of a four-injection brachial plexus block performed at the axillary (Group Axillary; n = 50) or at the humeral (Group Humeral; n = 50) level using a peripheral nerve stimulator. All patients received 40 mL of a mixture of equal parts of 0.5% bupivacaine and 2% lidocaine. Four patients in Group Axillary and two in Group Humeral were excluded from the study because all of the four nerves were not localized in the allotted time. The incidence of complete block (91% versus 89%), defined as block of all the sensory areas below the elbow, and the onset time of sensory block (15 +/- 6 min versus 16 +/- 7 min) were not different between the groups. The performance time was shorter in Group Humeral (7 +/- 2 min versus 8 +/- 2 min; P < 0.005). Block performance pain was lower in Group Axillary patients (16 +/- 9 min versus 23 +/- 12 min; P < 0.005). For four-injection brachial plexus block, we conclude that both the axillary and the humeral approaches provide a high success rate and a rapid onset of sensory anesthesia; the differences found between the groups could be considered clinically unimportant. IMPLICATIONS: Two methods of brachial plexus block using a nerve-stimulator were compared in a prospective study. A four-injection technique was performed at the axillary or at the humeral level. Both approaches provided a fast onset and a high success rate. The differences found between the groups could be considered clinically unimportant.     

Clonidine as an adjuvant to local anaesthetic axillary brachial plexus block: a randomized, controlled study

Background. We compared the effects of clonidine added to levobupivacaineand bupivacaine on axillary brachial plexus block as well asthe effectiveness of levobupivacaine alone compared with bupivacainealone. Methods. In this prospective, randomized, controlled, double-blindtrial, four groups of 20 patients each were investigated, using(i) 40 ml of levobupivacaine 0.5% plus 0.150 mg of clonidine,(ii) 40 ml of levobupivacaine 0.5% plus 1 ml of NaCl 0.9%, (iii)40 ml of bupivacaine 0.5% plus 0.150 mg of clonidine, and (iv)40 ml of bupivacaine 0.5% plus 1 ml of NaCl 0.9%, respectively.The onset of motor and sensory block and duration of sensoryblock were recorded. Results. There was no significant difference in duration betweengroups, but a significantly higher variance (P<0.001) wasfound in the two groups with clonidine than in the two groupswithout. Conclusions. These findings suggest responder and non-responderbehaviour is a result of the addition of clonidine.     

Increasing the injection volume by dilution improves the onset of motor blockade,but not sensory blockade of ropivacaine for brachial plexus block

BACKGROUND AND OBJECTIVE: Ropivacaine used for axillary plexus block provides effective motor and sensory blockade. Varying clinical dosage recommendations exist. Increasing the dosage by increasing the concentration showed no improvement in onset. We compared the behaviour of a constant dose of ropivacaine 150 mg diluted in a 30, 40 or 60 mL injection volume for axillary (brachial) plexus block. METHODS: A prospective, randomized, observer-blinded study on patients undergoing elective hand surgery was conducted in a community hospital. Three groups of patients with a constant dose of ropivacaine 150 mg, diluted in 30,40 or 60 mL NaCl 0.9%, for axillary plexus blockade were compared for onset times of motor and sensory block onset by assessing muscle strength, two-point discrimination and constant-touch sensation. RESULTS: Increasing the injection volume of ropivacaine 150 mg to 60 mL led to a faster onset of motor block, but not of sensory block, in axillary plexus block, compared with 30 or 40 mL volumes of injection. CONCLUSIONS: The data show that the onset of motor, but not of sensory block, is accelerated by increasing the injection volume to 60 mL using ropivacaine 150 mg for axillary plexus block. This may be useful for a more rapid determination of whether the brachial plexus block is effective. However, when performing surgery in the area of the block, sensory block onset seems more important.     

Levobupivacaine and ropivacaine in the infraclavicular brachial plexus block

AIM: Infraclavicular brachial plexus block were first described by Raj, yet this block remained underutilized despite theoretical advantages. The aim of this prospective, randomized study was to compare equipotent doses of levobupivacaine and ropivacaine. METHODS: For this prospective, randomized study we have enrolled, after informed consent, 30 patients of both sexes, ASA status I-II, who were going to receive surgery to the forearm or hand with tourniquet position on the arm. The infraclavicular plexus block was performed by using vertical technique. The block was performed with 30 mL of levobupivacaine 0.5% or ropivacaine 0.75%. RESULTS: No differences were reported between 2 groups in terms of demographic data. The onset-time for motor block was greater for ropivacaine group (p<0.05); the sensitive block was longer in levobupivacaine group (p<0.05). CONCLUSIONS: The long duration of sensory block associated with the with good analgesia, less toxicity and the pharmacodynamic properties of levobupivacaine include this new local anaesthetic as a valid choice respect other local anaesthetic for infraclavicular plexus block.     

左旋布比卡因臂丛神经阻滞的药代动力学

目的研究左旋布比卡因用于臂丛神经阻滞的临床药代动力学特性。方法10例择期上肢手术患者,0.375%左旋布比卡因0.4ml/kg行肌间沟入路臂丛神经阻滞。于注药前及注药后10、20、30、45、60、90、120、180、240、360、480和720min采血2ml,分离血浆,高效液相色谱法测定左旋布比卡因血药浓度。所得数据经3P97药代动力学软件处理,选择最佳房室模型,绘出血药浓度-时间曲线,求得药代动力学参数。结果左旋布比卡因血药浓度-时间数据符合二房室开放模型,主要药代动力学参数:分布半衰期(t1/2α)(0.46±0.21)h、消除半衰期(t1/2β)(4.58±0.66)h、达峰时间(Tmax)(0.31±0.19)h、峰值浓度(Cmax)(0.95±0.31)mg/L、曲线下面积(AUC)(3.76±0.52)mg.h-1.L-1、清除率(CL)(0.42±0.07)L/h和表观分布容积(Vd)(1.34±0.44)L/kg。结论0.375%左旋布比卡因可安全用于臂丛神经阻滞,其临床药代动力学符合二房室开放模型。