3-in-1 lumbar plexus block for muscle biopsy in malignant hyperthermia patients. Amide local anaesthetics may be used safely

A 3-in-1 lumbar plexus block with the aid of a nerve stimulator was performed in 32 patients and a psoas compartment block was performed in five patients for muscle biopsy of the upper leg for diagnosis of malignant hyperthermia (MH) susceptibility. Twenty-two patients were found to be MH susceptible by the in vitro contracture test. Twenty patients received 40 ml prilocaine 1.5% with epinephrine 1:200,000 and two received 40 ml bupivacaine 0.5% with epinephrine 1:200,000 without any untoward reaction. The 3-in-1 block provides a high success rate and excellent analgesia for muscle biopsy of the upper leg. Amide local anaesthetics are safe in MH-susceptible patients.     

Comparison of sciatic psoas compartment block and sciatic femoral 3-in-1 block for knee arthroscopy

STUDY OBJECTIVES: To compare the clinical effectiveness of two peripheral nerve block techniques combined with sciatic nerve block: sciatic psoas compartment (SPC) and sciatic femoral 3-in-1 (SF 3-in-1) block. DESIGN: Prospective, randomized study. SETTING: Military medical academy hospital. PATIENTS: Thirty-six ASA physical status I patients, aged 20 to 33 years, undergoing elective knee arthroscopy. INTERVENTIONS: Patients having SPC block (n = 19) or SF 3-in-1 block (n = 17) received 40 mL of a mixture of solution containing 15 mL of 0.5% bupivacaine, 15 mL of 2.0% prilocaine, and 10 mL of 0.9% sodium chloride. In both groups, the sciatic nerve was blocked with 20 mL of the same solution. An intravenous bolus injection of fentanyl 0.1 mg was used if patients complained of pain. MEASUREMENTS AND MAIN RESULTS: None of the patients in the SPC group experienced pain owing to the applied tourniquet during the operation, whereas 7 patients from the SF 3-in-1 group (41.2 %) reported tourniquet pain. All SF 3-in-1 group patients but only 5 patients (26.3 %) in the SPC group required fentanyl during the operation. In addition, 7 patients in the SF 3-in-1 group required second doses of fentanyl. Patient satisfaction was significantly higher in the SPC group than in the SF 3-in-1 block group (P < 0.0001). CONCLUSIONS: Both SPC and SF 3-in-1 provided sufficient anesthetic efficacy for knee arthroscopy. However, SPC may be preferable to SF 3-in-1 block owing to better patient satisfaction and less requirement for opioid analgesics.     

Are peripheral and neuraxial blocks with ultrasound guidance more effective and safe in children?

Background and aims:  The efficacy and safety of ultrasound guided (USG) pediatric peripheral nerve and neuraxial blocks in children have not been evaluated. In this review, we have looked at the success rate, efficacy and complications with USG peripheral nerve blocks and compared with nerve stimulation or anatomical landmark based techniques in children.
Methods:  All suitable studies in MEDLINE, EMBASE Drugs and Cochrane Evidence Based Medicine Reviews: Cochrane Database of Systemic Reviews databases were identified. In addition, citation review and hand search of recent pediatric anesthesia and surgical journals were done. All three authors read all selected articles independently and a consensus was achieved. All randomized controlled trials (RCTs) comparing USG peripheral and neuraxial blocks with other techniques in children were included.
Results:  Ultrasound guidance has been demonstrated to improve block characteristics in children including shorter block performance time, higher success rates, shorter onset time, longer block duration, less volume of local anesthetic agents and visibility of neuraxial structures.
Conclusion:  Clinical studies in children suggest that US guidance has some advantages over more traditional nerve stimulation–based techniques for regional block. However, the advantage of US guidance on safety over traditional has not been adequately demonstrated in children except ilio-inguinal blocks.     

Ultrasonographic guidance for sciatic and femoral nerve blocks in children

Background: Recent studies have shown that ultrasound guidance for paediatricregional anaesthesia can improve the quality of upper extremityand neuraxial blocks. We therefore investigated whether ultrasoundguidance for sciatic and femoral nerve blocks prolongs sensoryblockade in comparison with nerve stimulator guidance in children. Methods: Forty-six children scheduled for surgery of one lower extremitywere randomized to receive a sciatic and femoral nerve blockunder either ultrasound or nerve stimulator guidance. Afterinduction of general anaesthesia, the blocks were performedusing an ultrasound-guided multiple injection technique untilthe nerves were surrounded by levobupivacaine, or by nerve stimulatorguidance using a predefined dose of 0.3 ml kg^–1 of levobupivacaine.An increase in heart rate of more than 15% of baseline duringsurgery defined a failed block. The duration of the block wasdetermined from the injection of local anaesthetic to the timewhen the patient received the first postoperative analgesic. Results: Two blocks in the nerve stimulator group failed. There wereno failures in the ultrasound group. The duration of analgesiawas longer in the ultrasound group mean (SD) 508 (178) vs 335(169) min (P < 0.05). The volume of local anaesthetic insciatic and femoral nerve blocks was reduced with ultrasoundcompared with nerve stimulator guidance [0.2 (0.06) vs 0.3 mlkg^–1 (P < 0.001) and 0.15 (0.04) vs 0.3 ml kg^–1(P < 0.001), respectively]. Conclusions: Ultrasound guidance for sciatic and femoral nerve blocks inchildren increased the duration of sensory blockade in comparisonwith nerve stimulator guidance. Prolonged sensory blockade wasachieved with smaller volumes of local anaesthetic when usingultrasound guidance.     

Kombinierter Ischiadikus/ 3-in-1-Block Prilocain 500 mg vs. 650 mg

The objective of the study was to investigate the clinical effectiveness of increasing the dosage of prilocaine for a combined 3-in-1/sciatic nerve block from 500 to 650?mg (open study with 29 patients compared with 30 patients from a former study) and to validate these findings in a second stage (randomised study comparing two groups of 30 patients each). Not only was clinical effectiveness improved by increasing the dose to 650?mg, but methaemoglobinaemia and toxicity were not relevant problems. With the higher dosage, development of the block was slightly faster (onset and completion); there were fewer unsatisfactory blocks; and clinically relevant plasma levels of methaemoglobin did not occur.     

Effects of ultrasound guidance on the minimum effective anaesthetic volume required to block the femoral nerve

Background: We tested the hypothesis that ultrasound guidance may reducethe minimum effective anaesthetic volume (MEAV₅₀) of ropivacaine0.5% required to block the femoral nerve compared with nervestimulation guidance. Methods: After standard premedication and sciatic nerve block were given,60 patients undergoing knee arthroscopy were randomly allocatedto receive a femoral nerve block with ropivacaine 0.5% usingeither nerve stimulation (group NS, n = 30) or ultrasound (groupUS, n = 30) guidance. The volume of the injected solution wasvaried for consecutive patients based on an up-and-down staircasemethod according to the response of the previous patient. Theinitial volume was 12 ml. A double-blinded observer evaluatedthe occurrence of complete loss of pinprick sensation in thefemoral nerve distribution, with concomitant block of the quadricepsmuscle: positive or negative responses within 30 min after theinjection determined a 3 ml decrease or increase for the nextpatient, respectively. Results: The mean (SD) MEAV₅₀ for femoral nerve block was 15 (4) ml (95%CI, 7–23 ml) in group US and 26 (4) ml (95% CI, 19–33ml) in group NS (P = 0.002). The effective dose in 95% of cases(ED₉₅) calculated with probit transformation and logistic regressionanalysis was 22 ml (95% CI, 13–36 ml) in group US, and41 ml (95% CI, fs 24–66 ml) in group NS. Conclusions: Ultrasound guidance provided a 42% reduction in the MEAV ofropivacaine 0.5% required to block the femoral nerve as comparedwith the nerve stimulation guidance.     

Duration of experimental nerve block by combinations of local anesthetic agents

The effects of bupivacaine-prilocaine and meperidine-lidocaine combinations (as compared with those of the agents used alone) on the duration of peripheral sensory nerve block were studied with the infraorbital nerve block model (IONB) in the rat, and those on motor block with spinal anesthesia (SA) in the mouse. The duration of bupivacaine-induced IONB was invariably prolonged when prilocaine was included in the solution. When included in 0.125% bupivacaine, 1.0% prilocaine had a slightly less pronounced enhancing efTect than 0.5% prilocaine (24–57% vs. 74%-104%, respectively). The duration of IONB with 1.0% prilocaine was significantly reduced (14–37%) by inclusion of 0.125% bupivacaine. In SA, inclusion in 0.125% bupivacaine of prilocaine (0.5% or 1.0%) prolonged motor block by 128% and 192%, respectively. When included in 0.25% bupivacaine, both 0.5% and 1.0% prilocaine significantly reduced the duration of SA, by 42% and 37%, respectively. With one exception, the duration of IONB by meperidine was significantly shortened (<44%) when lidocaine was included in the solution. In SA, inclusion of 2% lidocaine with 2% meperidine did not affect the duration of meperidine-induced motor block. The duration of SA obtained with the combination of 4% lidocaine and 4% meperidine was 45% shorter than that induced by 4% meperidine alone. The reasons for these variable effects are not clear, but may be due to interaction or antagonism at any of multiple sites.     

患者不同浓度局麻药配伍坐骨神经阻滞的效果

目的比较患者不同浓度局麻药配伍坐骨神经阻滞（经典后路法）的效果。方法择期行单侧膝关节及膝以下手术患者60例，随机分为2组（n=30）：高浓度组（1．5％利多卡因＋0．5％罗哌卡因）和低浓度组（1％利多卡因＋0．375％罗哌卡因）。依次给予腰丛阻滞和坐骨神经阻滞（经典后路法），以周围神经刺激器引出足跖屈为坐骨神经阻滞的目标运动反应。自注入所有局麻药后的45min内，每隔5分钟评价坐骨神经分支支配区域的感觉、运动阻滞情况。记录2组感觉阻滞和运动阻滞的起效时间、作用持续时间以及术中和术后并发症。结果2组坐骨神经阻滞的成功率差异无统计学意义（P〉0．05）。与高浓度组比较，低浓度组感觉、运动阻滞起效时间延长（P〈0．05），但2组感觉、运动阻滞作用时间比较差异无统计学意义（P〉0．05）。2组术中和术后均未出现并发症。结论采用低浓度的局麻药（1％利多卡因＋0．375％罗哌卡因）配伍即可提供满意的坐骨神经阻滞效果。     

On the relative potency of amino–amide local anaesthetics in vivo

With the aim of comparing the analgesic effectiveness of lidocaine, prilocaine, bupivacaine and etidocaine in vivo , a study of the relationships between dose and duration of infraorbital nerve block (IONB) of various intensities (IONB degrees 3–10) was performed in the rat. With increasing doses longer durations of action were obtained. Further analyses were performed using multiple regression analysis. The log (dose) – duration lines for bupivacaine and etidocaine were found to be linear, whereas those for lidocaine in degree 3 and degree 10 IONB and for prilocaine in degree 10 IONB were so only after omission of some data. The only comparisons yielding no deviation from parallelism of log (dose) – duration lines were etidocaine vs. lidocaine at IONB degree 10 and lidocaine vs. prilocaine and bupivacaine vs. etidocaine at IONB degree 3. The difference between these agents with respect to their duration of action at all dose levels amounted to 113 minutes (M s.e.m.) for etidocaine vs. lidocaine (IONB degree 10), 27 4 min for prilocaine vs. lidocaine and 54 5 min for bupivacaine vs. etidocaine (IONB degree 3). For all other comparisons the log (dose) duration lines deviated from parallelism, i.e. differences between agents with respect to their duration of action were found to be dose–dependent. The slopes of the log (dose) – duration lines were found to correlate closely to the log (partition coefficient) and log (protein binding) of the investigated agents.     

Ultrasound guidance characteristics and efficiency of suprazygomatic maxillary nerve blocks in infants: a descriptive prospective study

Background: Bilateral suprazygomatic maxillary nerve blocks approach improves pain relief after palate surgery. We report the feasibility and efficiency of ultrasound‐guided suprazygomatic maxillary nerve blocks in cleft palate repair in children. Methods: Twenty‐five children scheduled to undergo surgical cleft palate repair were included. Ultrasound‐guided suprazygomatic maxillary blocks were performed according to landmarks previously defined. The ultrasound probe was located optimally over the maxilla and under the zygomatic bone to visualize the pterygopalatine fossa. 0.15·ml·kg^?1 of 0.2% ropivacaine was injected bilaterally. Feasibility of block, spread of local anesthetic, pain scores and side effects were noted. Results: Fifty ultrasound‐guided suprazygomatic maxillary nerve blocks were performed in 25 children. The needle movement was seen in all cases using an out‐of‐plane approach. The spread of LA was clearly observed in 94% (47/50) of cases. A poor ultrasound imaging was found in 4% (2/50), and the spread of LA was not identified in 2% of case (1/50). The median time to perform the block was 56 s (35–120 s). The median pain scores and consumption of nalbuphine were low during the study period. 80% of patients did not require continuous opioid infusion. No complication related to maxillary blocks was reported. Conclusion: With a very low technical failure rate and a good clinical success rate, ultrasound appears to be a useful and simple tool to aid suprazygomatic maxillary nerve block in children.     

Three‐dimensional ultrasound‐assisted popliteal catheter placement revealing aberrant anatomy: implications for block failure

Background: The current means of introducing continuous sciatic catheters include nerve stimulation, with or without catheter stimulation techniques. More recently, ultrasound has been utilized to facilitate catheter placement. Methods: This case represents a stimulating catheter‐guided continuous block facilitated by three‐dimensional ultrasound, which revealed aberrant anatomy with proximal and wide bifurcation of the sciatic nerve with implications for block failure. Results: Before ultrasound imaging secondary failures were attributed to catheter misplacement or dislodgement. Conclusion: Because of this case observation, our current practice is to use ultrasound confirmation of the bifurcation of the nerve of all popliteal catheter placements, particularly catheters placed in patients having ambulatory procedures to prevent secondary failure of catheters at home.     

A study of regional nerve blocks and local anesthetic creams (Prilox) for donor sites in burn patients

BACKGROUND: Burn patient requires multiple visits to the operation theatres and undergoing anesthesia with its attendant risks and post anesthesia recovery. It is possible now with the availability of local anesthetic creams like Prilox to conduct these procedures in the minor OT without any discomfort to the patient. MATERIALS AND METHODS: Hundred patients of post burn raw areas were selected. These patients had at least one area of healthy skin on anterior, medial or lateral thigh. No patient had a known drug allergy. The age group varied from 5 to 75 years with no bias towards any sex. These patients were then given anesthesia according to the group, and were assessed for the ease of grafting, amount of graft being harvested, subjective pain score, post operative pain relief and any post operative complication. The nerve block technique being used was either femoral and/or LCT block or 3-in-1 block and popliteal fossa block. RESULTS: Both the group of patients had a virtual painless process of skin grafting. It is safe in selected patients to combine the two techniques in order to harvest larger areas. DISCUSSION: Both techniques of local anesthestic creams and nerve block are safe and convenient to use. Nerve blocks are more useful where larger grafts are required, the creams being more useful in children and where less graft is required.     

Die kombinierte „3-in-1“/Ischiadicus-Blockade Blockadeerfolg,Serumspiegel und Nebenwirkungen bei Einsatz von je 700 mg Mepivacain 1% ohne und mit Adrenalin sowie Prilocain 1%

A high dose of local anaesthetic is necessary for the combined “3-in-1”/sciatic nerve block. Prilocaine is recommended for its low toxicity. However, in some patients prilocaine results in pronounced methaemoglobin formation due to toludine. Little has been known hitherto about the use of high-dose mepivacaine for the combined 3-1/sciatic nerve block. This study was undertaken to compare the use of 700?mg mepivacaine 1% and of 700?mg prilocaine 1%. Methods. The study was approved by the ethics committee of our hospital. Once their informed consent had been obtained in writing 3×20 patients (ASA 1–2) undergoing planned surgery on the foot or ankle joint were enrolled in the study. The patients were randomized to the following three groups on a double-blind basis: group 1,700?mg mepivacaine without epinephrine; group 2,700?mg mepivacaine with 0.2?mg epinephrine (1:350000); group 3,700?mg prilocaine 1%. Arterial blood samples for determination of local anaesthetic serum levels were collected over a 120-min period. We determined methaemoglobin and oxygen saturation before and 120?min after the blockade and continued these measurements for 6?h in group 3. At 15-min intervals, all patients were questioned about early signs of toxicity. The perioperative monitoring including blood pressure, ECG and pulse oximetry. Data were analysed using ANOVA and Student's t-test, P<0.05 considered statistically significant. Results. The blocking efficacy did not differ among the groups (groups 1, 2, 3: 90%, 95%, 90%). The maximum mepivacaine serum level in group 1 was 3.91?μg/ml ±0.95 and 2.94?μg/,ml ±0.58 in group 2 (Fig. 2). Over the entire observation period the addition of epinephrine resulted in a significant reduction of the serum level (between 60.3% at t=15 min and 19.7% at t=120?min). In the prilocaine group the maximum serum level was 2.07?μg/ml ±0.56, significantly less than in either mepivacaine group. No patient showed signs or symptoms of local anaesthetic toxicity. In the prilocaine group there was wide variation in methaemoglobin formation among the patient, with a median of 10.1% (Fig. 3, Table 3). Three patients showed a maximum methaemoglobinemia between 16% and 17%. Five patients were still cyanotic after 6?h when they were transferred to the ward. The fractional SaO₂ values amounted to 88% (median) with a minimum of 80.3%. Conclusion. Both mepivacaine 1% and prilocaine 1% are appropriate local anaesthetics for the combined 3-in-1/sciatic nerve block at a dose of 700?mg. There was no difference in the blocking efficacy. No patient showed clinical signs or symptoms of a local anaesthetic toxicity. Following prilocaine we are sometimes faced with high methaemoglobinemia, which may necessitate prolonged monitoring.     

Effects of using the posterior or anterior approaches to the lumbar plexus on the minimum effective anesthetic concentration (MEAC) of mepivacaine required to block the femoral nerve: a prospective, randomized, up-and-down study

BACKGROUND AND OBJECTIVES: To evaluate if psoas compartment block requires a larger concentration of mepivacaine to block the femoral nerve than does an anterior 3-in-1 femoral nerve block. METHODS: Forty eight patients undergoing anterior cruciate ligament repair were randomly allocated to receive an anterior 3-in-1 femoral block (femoral group, n = 24) or a posterior psoas compartment block (psoas group, n = 24) with 30 mL of mepivacaine. The concentration of the injected solution was varied for consecutive patients using an up-and-down staircase method (initial concentration: 1%; up-and-down steps: 0.1%). RESULTS: The minimum effective anesthetic concentration of mepivacaine blocking the femoral nerve in 50% of cases (ED(50)) was 1.06% +/- 0.31% (95% confidence interval [CI], 0.45%-1.68%) in the femoral group and 1.03% +/- 0.21% (95% CI, 0.6%-1.45%) in the psoas group (P = .83). The lateral femoral cutaneous and obturator nerves were blocked in 4 (16%) and 5 (20%) femoral group patients as compared with 20 (83%) and 19 (80%) psoas group patients (P = .005 and P = .0005, respectively). Intraoperative analgesic supplementation was required by 15 (60%) and 5 (20%) patients in the femoral and psoas groups, respectively (P = .01). CONCLUSIONS: Using a posterior psoas compartment approach to the lumbar plexus does not increase the minimum effective anesthetic concentration of mepivacaine required to block the femoral nerve as compared with the anterior 3-in-1 approach, and provides better quality of intraoperative anesthesia due to the more reliable block of the lateral femoral cutaneous and obturator nerves.     

Feasibility of Nerve Stimulator as a Supplemental Aid for Lumbar Transforaminal Epidural Block

Background

The purpose of this study was to evaluate the clinical feasibility of an electric nerve stimulator in a lumbar transforaminal epidural block.

Methods

Using an electric nerve stimulator, transforaminal epidural blocks were performed in 105 segments of 49 patients who presented with lower back pain with radiating pain to lower extremities. The contrast medium was injected to delineate the nerve root after positioning an insulated needle at the intervertebral foramen under fluoroscopic guidance. Then, the nerve root was electrically stimulated with the insulated needle to confirm whether or not the same radiating pain was evoked.

Results

Of the 105 foraminal segments, the same radiating pain was evoked at 0.5 mAh in 47 segments (44.8%), at 1.0 mAh in 22 (21.0%), at 1.5 mAh in 3 (2.9%), at 2.0 mAh in 15 (14.3%), at 2.5 mAh in 4 (3.8%), and at 3.0 mAh in 5 (4.8%). No response was observed in 9 segments (8.6%). The fluoroscopy revealed successful positioning of the needle in the patients with an evoked radiating pain over 2.0 mAh. The visual analogue scale (VAS) obtained for pain improved from a mean of 7.5 to 2.7 after the block (p = 0.001). In the 9 cases without response to electrical stimulation, the patients showed an improvement on VAS from 7.8 to 3.4 (p= 0.008) also.

Conclusions

A nerve stimulator can help to predict the accuracy of needle positioning as a supplemental aid for a successful lumbar transforaminal epidural block. It is sufficient to initiate a proper stimulation amplitude of the nerve at 2 mAh.     

Prilocaine in lumbosacral plexus block – general efficacy and comparison of nerve stimulation amplitude

The significance of the threshold amperage of peripheral nerve stimulation (PNS) for the efficacy and latency of sciatic block is shown in a controlled randomized study of stimulation amplitude. In all cases the block was complete within a short time when the threshold amperage was 0.3 mA or less. Incomplete motor and sensory blocks occurred with higher stimulation amplitudes of 0.5 and 1.0 mA. In view of these results a prospective study of the clinical efficacy of 852 combined sciatic/3-in-1 blocks using prilocaine, and performed by means of peripheral nerve stimulation was carried out. No CNS or cardiovascular complications, no problems resulting from methaemoglobinaemia and, above all, no nervous lesions were observed. The limiting factor for surgery of the lower limb with this method of anaesthesia is the tolerance of the femoral tourniquet which depends mainly on the efficacy of the 3-in-1 block. Ninety-one per cent of the combined blockades were primarily successful when there was no tourniquet at all, and 87% when the tourniquet was placed on the lower leg. In the course of surgery with a femoral pneumatic tourniquet, only 55% of the blocks did not require supplement when 20 ml of 1% prilocaine was used for the 3-in-1 block, while 72% and 74% were efficacious with 30 ml and 35 ml, respectively. The efficacy of the sciatic block proved to be extremely high (> 95%), its success depending on the dosage of the local anaesthetic and correct execution of the peripheral nerve stimulation.