Peripheral Nerve Blockade Research Articles

The role of peripheral nerve stimulation in the era of ultrasound-guided regional anaesthesia.

With the widespread use of ultrasound for localising nerves during peripheral nerve blockade, the value of electrical nerve stimulation of evoked motor responses has been questioned. Studies continue to show that, compared with nerve stimulation, ultrasound guidance alone leads to: significantly improved block success; decreased need for rescue analgesia; decreased procedural pain; and lower rates of vascular puncture. Nerve stimulation combined with ultrasound does also not appear to improve block success rates, apart from those blocks where the nerves are challenging to view, such as the obturator nerve. The role of nerve stimulation has changed in the last 15years from a technique to locate nerves to that of an adjunct to ultrasound. Nerve stimulation can serve as a monitor against needle-nerve contact and may be useful in avoiding nerves that are in the needle trajectory during specific ultrasound guided techniques. Nerve stimulation is also a useful adjunct in teaching novices ultrasound-guided regional anaesthesia, especially when the position and or appearance of nerves may be variable. In this review, the changing role of nerve stimulation in contemporary regional anaesthetic practice is presented and discussed.

A Randomised Controlled Study of Two Different Doses of Bupivacaine in Ultrasound Guided Axillary Brachial Plexus Block

Introduction: The use of Ultrasound (USG) for needle precision aids in reduction of local anaesthetic volume needed for peripheral nerve blockade. Conventional dosages of 30 to 40 mL of local anaesthetic mixture have been used in peripheral nerve blockades but using a lesser volume will reduce the incidence of local anaesthesia associated systemic toxicity. Aim: To assess the efficacy of two different doses 20 mL and 25 mL of Bupivacaine in USG guided axillary plexus block. Materials and Methods: Sixty patients requiring forearm and hand surgeries were randomised into two groups. Group A received low volume (20 mL of 0.375% bupivacaine) and group B received intermediate volume (25 mL of 0.375% bupivacaine). The quality of anaesthesia in regards to sensory and motor blockade, duration of analgesia, haemodynamic variability and complications were evaluated. Successful block was defined by Vester Anderson’s criteria. Duration of analgesia was measured using Visual Analogue Scale (VAS). Statistical comparison of all continuous variables were assessed utilising Student’s t-test and Mann-Whitney U-test as applicable. Results: No significant difference in onset times were observed as far as sensory and motor blockade was concerned between the two groups A and B with p-values of 0.69 and 0.40, respectively. Group B had significantly longer duration of block in comparison with Group A (p<0.001). Two patients in group A and one patient in Group B required supplemental analgesia with fentanyl boluses. Haemodynamics were stable and no complications were seen in both the groups. Conclusion: Lower volume of Bupivacaine is convincingly prudent for regional blockade under USG guidance than suggested in literature.

Retrospective chart review of perioperative pain management of patients having surgery for closed ankle fractures using peripheral nerve blocks at a level one trauma center.

The objective of this investigation was to evaluate the effect of preoperative peripheral nerve blockade on pain outcomes after ankle fracture surgery. After approval from our institutional review board, a Current Procedural Terminology code search was performed of all patients within our institution over a 3-year data collection period (August 2016-June 2019). This resulted in 177 subjects who underwent isolated closed ankle fracture open reduction internal fixation (ORIF), of which 71 subjects met inclusion criteria. Results of the primary outcome measures found no difference in the mean postoperative care unit (PACU) pain scores between the groups (2.39 ± 2.91 vs 3.52 ± 3.09; P = 0.1724) nor the frequency of those who reported only mild pain (63.0% vs 47.10%; P = 0.2704). Subjects who received a peripheral nerve block spent more time in the PACU before discharge (2.06 ± 1.05 vs 0.94 ± 1.21 hours; P = 0.0004). Subjects receiving a peripheral nerve block were more likely to be given no analgesics in the PACU (38.9% vs 11.8%; P = 0.042) and less likely to receive a narcotic analgesic in the PACU (53.7% vs 82.4%; P = 0.047). Although the results of this investigation demonstrate no significant difference in the mean PACU pain scores, they do demonstrate a significant difference in the amount of pain medication given in the PACU setting. This information will be used for future investigations of this discrepancy between pain perception and need for immediate postoperative pain medications as it relates to multimodal pain control in the setting of ankle fracture surgery.

Local anaesthetic adjuncts for peripheral regional anaesthesia: a narrative review.

Moderate-to-severe postoperative pain persists for longer than the duration of single-shot peripheral nerve blocks and hence continues to be a problem even with the routine use of regional anaesthesia techniques. The administration of local anaesthetic adjuncts, defined as the concomitant intravenous or perineural injection of one or more pharmacological agents, is an attractive and technically simple strategy to potentially extend the benefits of peripheral nerve blockade beyond the conventional maximum of 8-14hours. Historical local anaesthetic adjuncts include perineural adrenaline that has been demonstrated to increase the mean duration of analgesia by as little as just over 1 hour. Of the novel local anaesthetic adjuncts, dexmedetomidine and dexamethasone have best demonstrated the capacity to considerably improve the duration of blocks. Perineural dexmedetomidine and dexamethasone increase the mean duration of analgesia by up to 6hour and 8hour, respectively, when combined with long-acting local anaesthetics. The evidence for the safety of these local anaesthetic adjuncts continues to accumulate, although the findings of a neurotoxic effect with perineural dexmedetomidine during in-vitro studies are conflicting. Neither perineural dexmedetomidine nor dexamethasone fulfils all the criteria of the ideal local anaesthetic adjunct. Dexmedetomidine is limited by side-effects such as bradycardia, hypotension and sedation, and dexamethasone slightly increases glycaemia. In view of the concerns related to localised nerve and muscle injury and the lack of consistent evidence for the superiority of the perineural vs. systemic route of administration, we recommend the off-label use of systemic dexamethasone as a local anaesthetic adjunct in a dose of 0.1-0.2mg.kg-1 for all patients undergoing surgery associated with significant postoperative pain.

Postoperative pain management in obstetrics and gynecology

The efficiency and quality of postoperative pain management may be considered unsatisfactory in Europe, as well as in the United States. Notwithstanding our better understanding of the physiology of pain and the development of new analgesia procedures, the improvement in satisfaction of patients has not be enhanced to the same degree. Obstetrics and gynecology are no exception to this statement. In fact, obstetrics and gynecology are surgical departments in which patients experience the greatest severity of postoperative pain. Current concepts of postoperative pain management are largely based on the administration of systemic non-opioid and opioid analgesics, supplemented with regional analgesia procedures and/or peripheral nerve blockades and, in some cases, the administration of other pain-relieving pharmaceutical agents. Based on the existing body of evidence, it would be appropriate to develop procedure-related concepts of analgesia. The concepts are based on the special circumstances of the respective department, and the scheme of analgesia is aligned to the respective interventions. Generally, however, a surgeon’s individual experience in dealing with the procedures and substances could be more significant than the theoretical advantages demonstrated in preceding investigations.

A comparison of liposomal bupivacaine to standard ropivacaine used in interscalene blocks for patients undergoing total shoulder arthroplasty

IntroductionWith the increasing incidence of total shoulder arthroplasty (TSA) being performed worldwide, there is a growing effort to reduce postoperative pain, the consumption of opioids (oral morphine equivalents [OMEs]), and subsequent in hospital length of stay. Although perioperative pain control regimens have been widely studied in patients undergoing TSA, patients continue to consume a significant quantity of opioids after surgery. In the era of an opioid epidemic, novel methods for the improvement of perioperative pain control is of utmost importance. The aim of this quality improvement initiative was to evaluate the effect of liposomal bupivacaine (LB) versus ropivacaine (RP) in interscalene peripheral nerve blockade (IPNB) in patients undergoing TSA. MethodsThis quality improvement initiative prospectively evaluated a consecutive group of patients undergoing TSA from June 2017 to September 2019. Patients were included if they underwent either an anatomic or reverse shoulder arthroplasty at a single institution by 1 of 2 fellowship trained surgeons. Patients were divided in to 2 temporal cohorts based on the US Food and Drug administration's approval of LB. Patients who received a RPIPNB were in the control group, while those who received a LBIPNB were in the treatment group. Outcome measures studied included average visual analog pain scores (VAS) at 24 and 48 hours in the hospital, OME's, and length of stay. ResultsA total of 114 patients underwent TSA and met the inclusion criteria to be included in the analysis: 58 received RPIPNB and 56 received LBIPNB. The cohorts did not demonstrate any statistically different attributes (eg, age, sex, dominance, smoking status, psychiatric disorders, diabetes, HTN, or ASA class). Difference in 24 hour and 48 hour VAS pain scores was significantly improved in the LBIPNB group as compared to the RPIPNB group (2.46 vs. 0.72, and 2.02 and −0.41, respectively P < .01). Difference in OME's and length of stay were not statistically significant. ConclusionDespite significantly improved pain scores at 24 hours and 48 hours, patients who received LBIPNB did not demonstrate a statistically significant improvement in LOS or quantity of OME's consumed. The discrepancy between subjective numeric pain scores and objective healthcare metrics is likely multifactorial, and brings to light the difficulty in determining the value of new pain regimens. In lieu of these findings, it is difficult to endorse or reject the use of LBIPNB in TSA. Without further studies demonstrating improved efficacy in reduction of opioid consumption and LOS, given the additional expense of the drug, its continued use remains uncertain. Level of EvidenceLevel III.

Patient-reported outcomes after femoral nerve block versus periarticular injections in patients undergoing total knee arthroplasty: A randomized controlled study

Total Knee Arthroplasty (TKA) is one of the most advanced surgical solutions for pain relief and mobility improvement in patients with end stage osteoarthritis. TKA patients experience severe postoperative pain. Recently, peripheral nerve blockade and Peri or intra-articular injections have been used successfully with fewer side effects when compared to the conventional analgesic techniques. Measuring quality of recovery (QoR) using QoR-15 scale is considered as an accepted and efficient scale for clarification the success of surgery and anaesthesia. One hundred and thirty adult patients scheduled for TKA were randomized into 2 groups: Femoral nerve block (FNB) group and periarticular injections (PAI) group. All patients completed the QoR before or on the day of surgery and at the end of the first post-operative day. Postoperative pain scores, opiod consumption and adverse effects of the drugs and techniques were also measured. Periarticular injectionsresulted in better analgesia at rest and on movement and less postoperative morphine consumption during the first 24 h postoperatively when compared to femoral nerve block. Global QoR-15 score was significantly higher in PAI when compared to FNB group. Periarticular injection of local anesthetics provides better quality of recovery and sufficient level of analgesia than does single shot femoral nerve block for patients undergoing total knee arthroplasty in early postoperative period.

Peripheral nerve blockade and novel analgesic modalities for ambulatory anesthesia.

Despite peripheral nerve blockade offering analgesic benefits and improving patient satisfaction, it has not been well adopted in ambulatory anesthesia. In this review, we aim to summarize the evidence underlying peripheral nerve blockade, local anesthetic adjuncts, continuous peripheral nerve blockade and novel analgesic modalities, with the objective to provide recommendations on postoperative analgesia optimization after peripheral nerve blockade in an ambulatory setting. Barriers to the widespread use of peripheral nerve blockade in ambulatory anesthesia could include lack of education and training, and increased anesthetic induction time. Strategies that have demonstrated promise to increase duration of action and attenuate rebound pain phenomenon after peripheral nerve blockade include multimodal analgesia, local anesthetic adjuncts and continuous infusion of local anesthetic. Dexamethasone has been demonstrated to be the most effective local anesthetic adjunct. Continuous peripheral nerve blockade is a reasonable alternative but at the expense of additional costs and logistical reorganization. There is currently insufficient data to promote the ambulatory use of liposomal bupivacaine, cryoanalgesia and percutaneous peripheral nerve stimulation. Educational programs and parallel processing may promote peripheral nerve blockade in an ambulatory setting, improving the patient experience in the postoperative period. Intravenous dexamethasone should be considered wherever appropriate as part of a multimodal analgesic strategy to optimize postoperative pain control.

A reliable septum exists between the lateral cord and medial and posterior cords in the costoclavicular region: Clinical and microanatomical considerations in brachial plexus anesthetic blockade.

The ultrasound-guided proximal infraclavicular costoclavicular block (PICB) appears popular but its results are inconsistent. We sought an accurate demonstration of septae formed between the brachial plexus cords. We performed in-plane, lateral-to-medial PICBs on 120 patients and recorded images. Once the most superficial lateral cord component was entered, a 0.4-0.6 mA current was applied to confirm needle placement; 5 ml of local anesthetic (LA) solution was then injected and its spread was observed and recorded. As the needle was advanced, the presence or absence of a hyperechoic linear structure was noted before the deeper compartment was reached, specifically looking for the possible displacement of such a septum. Upon initial scanning, a septum was observed in 67 of the 120 patients (46.2%). However, there was clear displacement of a linear septum between the lateral cord compartment and the medial and posterior cord compartments that prevented spread between the compartments in 94.16% of patients. Piercing the septum evoked motor responses from the medial or posterior cord. The same anatomical regions were studied microanatomically by analyzing cross-sections obtained with the same approach angle as the ultrasound probe. Intraplexus fascial septae that bundled the medial and posterior cords into one compartment and separated them from the lateral cord were demonstrated and confirmed microanatomically. This suggests the need for two separate injections (or two separate catheter placements for continuous peripheral nerve blockade) into the superficial and deep compartments to ensure LA spread around all three cords of the brachial plexus at this level.

Placenta accreta spectrum disorders - Peri-operative management: The role of the anaesthetist.

The incidence of placenta accreta spectrum (PAS) is increasing and will become more commonly encountered by obstetric anaesthetists in the elective and emergency settings. Significant maternal and neonatal morbidity is associated with these disorders, and hence it is important for anaesthetists to have early involvement in perioperative planning. Major haemorrhage should be anticipated and requires robust perioperative preparation including Patient Blood Management (PBM) and use of intraoperative strategies for haemorrhage management wherever possible. Several institutions have demonstrated good outcomes with regional anaesthesia alone, but the choice of anaesthetic technique requires individualised planning considering patient, anaesthetic and surgical factors. Optimisation of postoperative analgesia needs additional consideration; it is key to good recovery, minimising the impact on quality of life and reducing the risk of persistent post-surgical pain. Further research is required to ascertain the optimal multi-modal analgesic regime including the role of peripheral nerve blockade.

Comparison of levobupivacaine alone and levobupivacaine with dexmedetomidine in supraclavicular brachial plexus block: A prospective randomized clinical trial

Supraclavicular brachial plexus block is the most suitable mode of anaesthesia for various upper limb surgeries. Dexmedetomidine added to local anaesthetics shortens the onset time and prolongs the duration of block and post-operative analgesia in the brachial plexus block. However, there remains limited knowledge of its analgesic efficacy and duration in peripheral nerve and nerve plexus blockade. d: This prospective randomized double-blinded study was conducted with 60 patients of ASA physical status class I/II, scheduled for elective unilateral upper limb surgery. Patients were randomized into 2 groups of 30 each. All patients in Group L received a brachial plexus block with 29 ml of 0.5% levobupivacaine + 1ml of normal saline. Group LD received 29 ml of 0.5% levobupivacaine + 1ml of dexmedetomidine 1ml(100mcg). The primary objectives were the onset and duration of sensory and motor block. The onset of sensory and motor block was earlier in Group L (12.4 ± 3.1 min and 20.5 ± 3.8 min) than Group LD (15.9 ± 2.7 min and 22.1 ± 3.2 min), (P = 0.0000 and 0.0801). The duration of sensory and motor block was longer in Group LD (1198.0 ± 48.5 min and 1178.3 ± 41.4 min) than Group L (710.3 ± 87.3 min and 688.7 ± 86.6 min), (P =0.0000). The duration of analgesia was longer in Group LD (1222.0 ± 49.2 min) than Group L (726.3 ± 91.1 min), (P &amp;#60; 0.0001). Dexmedetomidine added with levobupivacaine prolongs the duration of sensory as well as motor block in brachial plexus block using the supraclavicular technique with haemodynamic stability.

Short-Term Effects of Deliberate Subparaneural or Subepineural Injections With Saline Solution or Bupivacaine 0.75% in the Sciatic Nerve of Rabbits.

Background: Ultrasound (US)-guided techniques for peripheral nerve blockade have revealed that intraneural injections are relatively frequent and not necessarily associated with neurological deficits.Objectives: To evaluate the short-term effects of deliberate injections performed under direct vision in two different sites of the sciatic nerve (ScN).Material and Methods: Seventy-two New Zealand white rabbits randomly assigned to one of four experimental groups (n = 18) were employed. All procedures were conducted at a proximal femoral level where the ScN incorporates the common peroneal nerve and the tibial nerve (TN). Fixed volumes of 0.5 ml of saline solution (ES group) or bupivacaine 0.75% (EB group) were administered extrafascicularly inside the paraneurium of the ScN or intrafascicularly (IS and IB groups) under the epineurium of the TN. Cross-sectional area (CSA) and relative echogenicity (RE) of the entire ScN were determined by US before injections, after injections, and at 3 and 7 days. ScN samples were obtained for structural and ultrastructural histopathological studies. Proprioceptive, sensorial, and motor function were clinically evaluated on a daily basis.Results: The CSA of the ScN increased significantly immediately after injections when compared with pre-injection values in all groups (p < 0.05). The RE of the ScN decreased in relation to pre-injection values in all groups (p < 0.05). The CSA and RE of the ScN returned to normal values 7 days after injections in almost all groups. Injected nerves showed histological signs of mild perineural inflammation. Histopathological scores were not significantly different between groups (p > 0.05). The architecture of the ScN was preserved in all rabbits at 3 days and in 31/32 rabbits at 7 days. A focal area of damaged nerve fibers with degeneration of the axons and myelin sheath affecting the TN was observed in one rabbit of the IB group. Nerve function was not clinically impaired in any case.Conclusion: Despite the lack of severe nerve disruption observed in most rabbits, the evidence of a focal area of damaged nerve fibers in one rabbit injected intrafascicularly with bupivacaine confirms that intrafascicular injections should be avoided as they may increase the risk of nerve damage.

Local anesthesia enhanced with increasing high-frequency ultrasound intensity.

The effect of local anesthetics, particularly those which are hydrophilic, such as tetrodotoxin, is impeded by tissue barriers that restrict access to individual nerve cells. Methods of enhancing penetration of tetrodotoxin into nerve include co-administration with chemical permeation enhancers, nanoencapsulation, and insonation with very low acoustic intensity ultrasound and microbubbles. In this study, we examined the effect of acoustic intensity on nerve block by tetrodotoxin and compared it to the effect on nerve block by bupivacaine, a more hydrophobic local anesthetic. Anesthetics were applied in peripheral nerve blockade in adult Sprague-Dawley rats. Insonation with 1-MHz ultrasound at acoustic intensity greater than 0.5W/cm2 improved nerve block effectiveness, increased nerve block reliability, and prolonged both sensory and motor nerve blockade mediated by the hydrophilic ultra-potent local anesthetic, tetrodotoxin. These effects were not enhanced by microbubbles. There was minimal or no tissue injury from ultrasound treatment. Insonation did not enhance nerve block from bupivacaine. Using an in vivo model system of local anesthetic delivery, we studied the effect of acoustic intensity on insonation-mediated drug delivery of local anesthetics to the peripheral nerve. We found that insonation alone (at intensities greater than 0.5W/cm2) enhanced nerve blockade mediated by the hydrophilic ultra-potent local anesthetic, tetrodotoxin. Graphical abstract.

Comparison of the effects of interscalene, supraclavicular and infraclavicular peripheral nerve blockades on perfusion index

Background: The perfusion index (PI) is a non-invasive method that measures the monitoring and success of peripheral nerve blocks in regional anesthesia. The perfusion index (PI) is an objective non-invasive method of measuring and monitoring the success of peripheral nerve blocks. We compare the effects of interscalene, supraclavicular and infraclavicular blocks on the perfusion index, with the aim being to contribute to the decision-making process regarding the type of block to be selected for surgeries in which increased perfusion is important. Methods: Included in the study were 60 patients aged between 18 and 60 years with an ASA (American Society of Anesthesiologists) I-II risk rating who were scheduled for upper extremity surgery. An equal number of patients were applied supraclavicular, interscalene and infraclavicular blockades, and the PI was measured non-invasively using a pulse-oximetry probe on the fingers on the same and opposite side of blockade at the beginning, at the 10 th , 20 th and 30 th minutes, postoperatively and in the post-anesthetic care unit (PACU). Results: After a successful blockade of brachial plexus in all patients, a statistically significant increase in PI values was detected. Aside from the initial values, the mean rate of change in PI was significantly higher in the interscalene group than the supraclavicular and infraclavicular groups (p < 0.001). Conclusion: PI can be used as a non-invasive monitoring method for the determination of the success of a brachial plexus blockade. Based on the results of the present study, an interscalene blockade may be preferred especially for surgeries in which an increase in tissue perfusion is desired due to its perfusion-enhancing properties when compared to supraclavicular and infraclavicular blocks.

A systematic review of the effect of regional anesthesia on diagnosis and management of acute compartment syndrome in long bone fractures.

Peripheral nerve blockade (PNB) is a useful tool for pain control in the perioperative period. However, there are significant concerns about the use of PNBs following acute orthopaedic trauma due to the theoretical risk of masking acute compartment syndrome (ACS). This study aims to systematically review the effects of PNBs on diagnosis of ACS following long bone fractures. A systematic review of the literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six studies, all of which were single-patient case reports, met criteria for inclusion in this review. Two studies reported a delay in diagnosis of ACS in the setting of PNB use, while four studies did not. Due to the low incidence of ACS, there is a paucity of literature available on ACS following PNB use in the setting of orthopedic trauma. There is no consensus in the literature about the safety of PNB use in the setting of acute long bone fractures, and this review could draw no conclusions from the literature, as the level of evidence is limited to case reports. PNBs should be administered to orthopedic trauma patients only in strictly controlled research environments, and surgeons should be highly cautious about using PNBs for orthopedic long bone fractures, particularly in cases at increased risk for developing ACS.

Avoidance of deep anesthesia and artificial airways in 1000 neonates and infants using regional anesthesia: A retrospective observational analysis.

Background and Aims:Current concerns related to the anesthetic neurotoxicity have brought a renewed interest in regional anesthesia. Regional anesthesia reduces the need for opioids and inhalational anesthetics. The immaturity of the neonatal and infant nervous system may render them more prone to neurotoxicity. We describe our technique of anesthesia, which minimizes the exposure to general anesthetics and reduces airway instrumentation because the operability is rendered by the regional block.Material and Methods:This was a retrospective case series of neonates and infants undergoing common surface surgeries. We describe our technique of anesthesia where regional blocks are the mainstay. We also put up the data pertaining to block effectiveness, technique, end-tidal sevoflurane concentration and complications.Results:One thousand patients, including neonates and infants, received central and peripheral nerve blockade. The failure rate in upper extremity blocks 0% without complications. 86.12% were given under ultrasonography (USG) guidance and 13.89% were given with peripheral nerve stimulation. The failure rate of sciatic block single shot and continuous was 0%. 92.53% were given with USG guidance while 7.46% received sciatic with nerve stimulation technique. Failure rate of caudal epidural block was 0. 78% requiring a rescue analgesic, 1.4% had blood in the needle. Out of the caudals, 33.33% were done with USG guidance and 66.67% blocks were given with traditional techniques. Out of the 322 penile + ring blocks given by traditional method, 1 block failed requiring rescue analgesics. The mean sevoflurane concentration was 1.2 +/- 0.32.Conclusion:It is feasible to conduct surface surgeries in the most vulnerable population such as neonates and infants under regional anesthesia without intubation and airway instrumentation.

Advances in regional anaesthesia and acute pain management: a narrative review.

Regional anaesthesia has undergone several exciting advances in the past few decades. Ultrasound-guided techniques of peripheral nerve blockade have become the gold standard thanks to the associated improvements in efficacy, ease of performance and safety. This has increased the accessibility and utilisation of regional anaesthesia in the anaesthesia community at large and is timely given the mounting evidence for its potential benefits on various patient-centred outcomes, including major morbidity, cancer recurrence and persistent postoperative pain. Ultrasound guidance has also paved the way for refinement of the technical performance of existing blocks concerning simplicity and safety, as well as the development of new regional anaesthesia techniques. In particular, the emergence of fascial plane blocks has further broadened the application of regional anaesthesia in the management of painful conditions of the thorax and abdomen. The preliminary results of investigations into these fascial plane blocks are promising but require further research to establish their true value and role in clinical care. One of the challenges that remains is how best to prolong regional anaesthesia to maximise its benefits while avoiding undue harm. There is ongoing research into optimising continuous catheter techniques and their management, intravenous and perineural pharmacological adjuncts, and sustained-release local anaesthetic molecules. Finally, there is a growing appreciation for the critical role that regional anaesthesia can play in an overall multimodal anaesthetic strategy. This is especially pertinent given the current focus on eliminating unnecessary peri-operative opioid administration.

Distal Bypass Grafting Using the Basilic–Cephalic Loop Vein for Chronic Limb-Threatening Ischemia under Peripheral Nerve Blockades in a Patient with Severely-Reduced Heart Function and End-Stage Renal Disease

A 51-year-old man with severe comorbidities required redo revascularization due to left chronic limb-threatening ischemia caused by a previous vein graft occlusion. The saphenous veins were not available due to previous surgeries. Femoro-posterior tibial artery bypass surgery was successfully performed using the basilic–cephalic loop vein under peripheral nerve blockades. This anesthesia allowed a series of surgical revascularizations without general anesthesia, and the postoperative courses were uneventful. The patient survived for 4 years with ambulatory status. In conclusion, loop graft can be an alternative single vein material for distal bypass when no saphenous veins are available.

The Duration of Nerve Block from Local Anesthetic Formulations in Male and Female Rats.

It is unknown whether there are sex differences in response to free or encapsulated local anesthetics. We examined nerve block duration and toxicity following peripheral nerve blockade in male and female rats. We studied the local anesthetic bupivacaine (free or encapsulated) as well as tetrodotoxin, which acts on a different site of the same voltage-gated channel. Sensory nerve blockade was 158.5 [139-190] minutes (median [interquartile range]) (males) compared to 173 [134-171] minutes (females) (p= 0.702) following bupivacaine injection, N= 8 male, 8 female. Motor nerve blockade was 157 [141-171] minutes (males) compared to 172 [146-320] minutes (females) (p= 0.2786). Micellar bupivacaine (N = 8 male, 8 female) resulted in sensory nerve blockade of 266 [227-320] minutes (males) compared to 285 [239-344] minutes (females) (p= 0.6427). Motor nerve blockade was 264 [251-264] minutes (males) compared to 287 [262-287] minutes (females) (p= 0.3823). Liposomal bupivacaine (N= 8 male, 8 female) resulted in sensory nerve blockade of 240 [207-277] minutes (males) compared to 289 [204-348] minutes (females) (p= 0.1654). Motor nerve blockade was 266 [237-372] minutes (males) compared to 317 [251-356] minutes (females) (p= 0.6671). Following tetrodotoxin injection (N= 12 male,12 female) sensory nerve blockade was 54.8 [5-117] minutes (males) compared to 54 [14-71] minutes (females) (p= 0.6422). Motor nerve blockade was 72 [40-112] minutes (males) compared to 64 [32-143] minutes (females) (p= 0.971). We found no statistically significant sex differences associated with the formulations tested. In both sexes, durations of nerve block were similar between micellar and liposomal bupivacaine formulations, despite the micellar formulation containing less drug.

Say what? Patients have poor immediate memory of major risks of interscalene block disclosed during the informed consent discussion

BackgroundPoor memory of disclosed risks can undermine informed consent and create medicolegal challenges. The extent to which patients remember the risks of peripheral nerve blockade following the informed consent discussion...