Adjuvants to local anesthetics: Current understanding and future trends

Comparative efficacy of hyperbaric bupivacaine vs hyperbaric ropivacaine in spinal anesthesia for cesarean section: A meta-analysis

BACKGROUND

Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections (CSs), but ropivacaine has emerged as a potential alternative. This meta-analysis compares the efficacy and safety of intrathecal hyperbaric bupivacaine vs hyperbaric ropivacaine for cesarean sections.

AIM

To systematically evaluate and compare the efficacy and safety of intrathecal hyperbaric bupivacaine and hyperbaric ropivacaine for spinal anesthesia in CSs.

METHODS

A thorough search of electronic databases was carried out to find pertinent randomized controlled trials (RCTs) comparing intrathecal hyperbaric ropivacaine and hyperbaric bupivacaine during CSs. PubMed, Cochrane database, Google Scholar, and Scopus were searched, and papers from January 2000 to January 2024 were deemed eligible and filtered using predetermined inclusion and exclusion criteria. Studies were assessed for methodological quality, and data were extracted for time to adequate anesthesia (sensory and motor blockade), duration of sensory and motor block, hemodynamic changes and side effect profile. The standardized mean difference with 95%CI was used for continuous data. Dichotomous variables were assessed using the Mantel-Haenszel test and the random effect model to compute the odds ratio.

RESULTS

Total 8 RCTs were selected from a pool of 119 search results for meta-analysis. The meta-analysis evaluated pooled effect sizes and assessed heterogeneity among the studies. The primary objective was to compare key outcomes to identify any significant variances in efficacy and safety profiles between two local anesthetics. The analysis revealed that the difference in the onset of sensory blockade between the two local anesthetics was statistically insignificant (P = 0.1586). However, the onset of motor blockade appeared to be faster with bupivacaine (P = 0.03589). Additionally, the regression of sensory and motor blockade occurred earlier in the ropivacaine group. Furthermore, the duration of the first analgesic effect was shorter with a significance level of P < 0.05. Regarding side effects profile, including hypotension, nausea, and shivering, the study did not observe any significant differences between the two groups.

CONCLUSION

This meta-analysis offers insights into the effectiveness and safety of hyperbaric bupivacaine vs ropivacaine for cesarean sections. Hyperbaric ropivacaine had a comparable safety profile and faster regression of sensory and motor blockade than hyperbaric bupivacaine, perhaps aiding early mobilization of parturient and facilitating mother-child bonding. Choosing ropivacaine may offer benefits beyond efficacy for cesarean section patients and short surgical procedures.

The efficacy of buprenorphine compared with dexmedetomidine in spinal anesthesia: a systematic review and meta-analysis

BACKGROUND

This study compares dexmedetomidine and buprenorphine as potential adjuvants for spinal anesthesia. Dexmedetomidine enhances sensory block and minimizes the need for pain medication, while buprenorphine, a long-acting opioid, exhibits a favorable safety profile compared to traditional opioids.

METHODS

PubMed, Cochrane and EMBASE were systematically searched in December 2023.

ELIGIBILITY CRITERIA

RCTs with patients scheduled for lower abdominal, pelvic, or lower limb surgeries; undergoing spinal anesthesia with a local anesthetic and buprenorphine or dexmedetomidine.

RESULTS

Eight RCTs involving 604 patients were included. Compared with dexmedetomidine, buprenorphine significantly reduced time for sensory regression to S1 (Risk Ratio [RR = -131.28]; 95% CI -187.47 to -75.08; I2 = 99%) and motor block duration (RR = -118.58; 95% CI -170.08 to -67.09; I2 = 99%). Moreover, buprenorphine increased the onset time of sensory block (RR = 0.42; 95% CI 0.03 to 0.81; I2 = 93%) and increased the incidence of postoperative nausea and vomiting (RR = 4.06; 95% CI 1.80 to 9.18; I² = 0%). No significant differences were observed in the duration of analgesia, onset time of motor block, time to achieve the highest sensory level, shivering, hypotension, or bradycardia.

CONCLUSIONS

The intrathecal administration of buprenorphine, when compared to dexmedetomidine, is linked to reduction in the duration of both sensory and motor blocks following spinal anesthesia. Conversely, buprenorphine was associated with an increased risk of postoperative nausea and vomiting and a longer onset time of sensory block. Further high-quality RCTs are essential for a comprehensive understanding of buprenorphine's effects compared with dexmedetomidine in spinal anesthesia.

Comparative Analysis of Intrathecal Bupivacaine With Fentanyl Versus Intrathecal Bupivacaine With Midazolam in Lower Abdominal and Lower Limb Surgeries

Many different adjuvants are added intrathecally along with local anaesthetics to prolong intraoperative and postoperative analgesia. Hence, this study aimed to compare intrathecal bupivacaine with fentanyl and bupivacaine with midazolam in lower abdominal and lower limb surgeries. Following permission from the Hospital Ethical Committee (Research Protocol No.: IESC/PGS/2022/143), the study was conducted on a sample of 60 patients, divided into two groups, Group F and Group M, with 30 patients each, representing the American Society of Anaesthesiologist's (ASA) grades I and II. The patients were between the ages of 18 and 60 and featured both males and females, scheduled to undergo elective surgical procedures on the lower abdomen and lower limbs via spinal anaesthesia. Group "F": 3 ml of 0.5% hyperbaric bupivacaine hydrochloride with 0.5 ml (25 mcg) of fentanyl (preservative-free) intrathecally. Group "M": 3 ml of 0.5% hyperbaric bupivacaine hydrochloride with 0.5 ml (2.5 mg) of midazolam (preservative-free) intrathecally. The primary aim was to study the onset of motor and sensory block and duration of analgesia with the addition of midazolam or fentanyl to 0.5% heavy bupivacaine in the sub-arachnoid block. A secondary aim was to evaluate the quality of anaesthesia and postoperative analgesia, determine the haemodynamic stability in the intraoperative and postoperative period in the two study groups, and observe any adverse effects of study drugs. Group F exhibited a substantially longer duration for both sensory (211.5 vs. 154.4 min) and motor blockade (269.8 vs. 214.6 min) compared to Group M, as well as a rapid onset time for both sensory (2.6 vs. 3.3 min) and motor blockade (3.1 vs. 3.9 min). Also, Group F had a significantly longer duration of effective analgesia compared to Group M (266 ± 15.9 vs. 197.6 ± 13.7 minutes). The addition of 0.5 ml (2.5 mg) Midazolam with 0.5% hyperbaric Bupivacaine intrathecally prolonged the duration of anaesthesia and postoperative analgesia; however, fentanyl 0.5 ml (25 mcg) has a more prolonged duration of intraoperative and postoperative analgesia.

Role of Adjuvants in Enhancing the Efficacy and Duration of Anesthesia Blocks: A Comprehensive Review

Anesthesia blocks are integral to modern pain management, offering targeted and effective relief for various surgical and procedural interventions. These techniques, including regional and peripheral nerve blocks (PNBs), involve the administration of local anesthetics to specific body areas, either through epidural, spinal, or direct nerve injections. While effective, incorporating adjuvants, substances added to local anesthetics, can significantly enhance their efficacy and prolong their duration. Adjuvants such as opioids, corticosteroids, alpha-2 agonists, and nonsteroidal anti-inflammatory drugs (NSAIDs) are used to amplify analgesic effects, reduce the need for general anesthesia, and improve postoperative outcomes. This review explores the role of adjuvants in optimizing anesthesia blocks, examining their mechanisms of action, clinical benefits, and safety considerations. Adding adjuvants can lead to enhanced pain control, reduced dosage of local anesthetics, and fewer systemic side effects. By integrating adjuvants into anesthesia practice, clinicians can achieve more precise and sustained pain management, tailoring approaches to individual patient needs and specific procedural demands. This comprehensive review highlights current evidence on using adjuvants, their impact on anesthesia block effectiveness, and future research directions. Understanding the role of adjuvants is crucial for improving patient outcomes and advancing pain management techniques in various surgical settings.

Comparison of two different doses of dexmedetomidine for continuous epidural analgesia for lower limb surgeries: A randomized double-blind study

Background and Aims

Bolus epidural dexmedetomidine provides potent analgesia but the incidence of hemodynamic instability is high. There are only a few studies that have evaluated the efficacy of epidural dexmedetomidine infusion but none of them compared different doses to find the optimum safe dose. We compared the analgesic efficacy and safety of two different doses of dexmedetomidine in continuous epidural for postoperative analgesia.

Material and Methods

Patients undergoing lower limb surgeries were divided randomly into two groups: Group I (n = 36) received an epidural infusion of 0.1% ropivacaine + 0.5 μg/kg/24 h of dexmedetomidine and Group II (n = 36) received epidural infusion 0.1% ropivacaine + 1 μg/kg/24 h of dexmedetomidine. Both groups received epidural infusion at the rate of 5 ml/h over 48 h postoperatively. Pain scores, demand for rescue analgesics, hemodynamic parameters, and sedation scores were compared between the groups. Statistical analysis was done using an independent t-test and Chi-square test.

Results

1 μg/kg group (Group II) had a significantly reduced pain score at all time intervals and less demand for rescue analgesia (P = 0.03). The severity of pain was more in the 0.5 μg/kg group (Group I), at all times (P = 0.000). Incidence hypotension was higher in Group II. Bradycardia was seen in two patients in Group II and none in Group I.

Conclusion

Dexmedetomidine in a dose of 1 μg/kg/24 h with 5 ml of 0.1% ropivacaine through epidural infusion provides better analgesia with a safe hemodynamic profile.

Role of Dexmedetomidine and Clonidine With Hyperbaric Ropivacaine in Subarachnoid Block: A Comprehensive Review

Subarachnoid block (SAB), a fundamental technique in regional anesthesia, offers efficient anesthesia for various surgical procedures with advantages including rapid onset, reliable anesthesia, and reduced systemic effects compared to general anesthesia. Hyperbaric ropivacaine, a long-acting local anesthetic, has gained popularity due to its favorable pharmacokinetic profile and safety profile. However, to extend the duration and enhance the quality of anesthesia provided by hyperbaric ropivacaine, adjuvants such as dexmedetomidine and clonidine are frequently employed. This comprehensive review explores the roles of dexmedetomidine and clonidine as adjuvants to hyperbaric ropivacaine in SAB. It examines their pharmacological mechanisms, clinical efficacy, safety profiles, and comparative effectiveness in prolonging analgesia and enhancing anesthesia. The review synthesizes evidence from clinical studies to delineate the synergistic effects of these adjuvants, their impact on patient outcomes, and their potential advantages over traditional anesthesia techniques. Through a detailed analysis of current literature and clinical practices, this review aims to provide insights into optimizing the use of dexmedetomidine and clonidine in SAB protocols. It discusses clinical implications, offers recommendations for practice, and identifies future research directions to further enhance the efficacy and safety of SAB using these adjuvants.

A Comprehensive Review on the Role of Melatonin's Anesthetic Applications in Pediatric Care

Anesthesia is critical to pediatric care, ensuring the safety and comfort of children undergoing medical procedures. With a growing interest in alternative anesthetic agents, melatonin has emerged as a promising candidate due to its sedative, analgesic, anti-inflammatory, and neuroprotective properties. This comprehensive review explores the potential applications of melatonin in pediatric anesthesia. We delve into the pharmacological characteristics of melatonin, its anesthetic properties, and its clinical applications in pediatric care, including preoperative sedation, adjunct to general anesthesia, postoperative pain management, and prevention of emergence delirium. Additionally, we discuss the safety profile of melatonin, potential adverse effects, and comparative analysis with traditional anesthetics. Finally, we highlight future research directions to provide insights into melatonin's role in pediatric anesthesia and its implications for clinical practice.

Safety and efficacy of dexmedetomidine in combination with local anesthetics for orthopedic nerve blocks: a systematic review and meta-analysis

INTRODUCTION

Peripheral nerve block, a common technique for managing postoperative pain and providing intraoperative analgesia, often includes adjuncts like dexmedetomidine (DEX) to enhance the effectiveness of local anesthetics. DEX, known for its α2-adrenoceptor agonist properties, extends sensory blockade and improves postoperative analgesia while offering sedative benefits. The objective of this study is to rigorously assess the effectiveness and safety of perineural DEX injection in orthopedic nerve block procedures, focusing on orthopedic surgeries to minimize heterogeneity and provide clearer insights for clinical practice.

EVIDENCE ACQUISITION

This meta-analysis, registered on PROSPERO, involved a comprehensive literature search across multiple databases, focusing on RCTs comparing DEX with local anesthetics for peripheral nerve blocks in orthopedic surgery patients. The eligibility criteria included adult participants and various nerve block methods in orthopedic surgeries. Studies were rigorously appraised for methodological quality using Cochrane Handbook guidelines. GRADE profiler 3.6 was used for evidence grading.

EVIDENCE SYNTHESIS

Among 1391 documents, 21 studies were included, focusing on DEX with local anesthetics in orthopedic nerve blocks. Findings showed significant improvements in analgesia duration, sensory and motor block duration, and reduced postoperative opioid consumption, with an increased risk of bradycardia. Quality assessments indicated moderate bias risk.

CONCLUSIONS

DEX with local anesthetics significantly enhances nerve block effectiveness, extending analgesia and block durations while reducing opioid need. However, it requires careful monitoring due to increased bradycardia risk. These findings highlight the need for cautious use in clinical practice, considering both potential benefits and adverse effects.

Comparison of Postoperative Analgesia Between Intrathecal Nalbuphine and Intrathecal Fentanyl in Infraumbilical Surgeries: A Double-Blind Randomized Controlled Trial

INTRODUCTION

Spinal anesthesia is a widely used regional anesthesia technique for surgeries below the umbilicus, but postoperative analgesia is of major concern due to the relatively short duration of the local anesthetic. Various drugs were used as an additive to local anesthetic to prolong the duration of postoperative analgesia. This study aims to compare the efficacy of nalbuphine and fentanyl as an intrathecal additive along with local anesthetic.

METHODOLOGY

A total of 166 patients aged between 18 and 65 years belonging to the American Society of Anesthesiologists (ASA) I and II undergoing elective infraumbilical surgeries were included in the prospective double-blind randomized controlled trial. The patients were allocated into two groups of 83 each. Group N was given 2.5 mL of 0.5% bupivacaine + 1 mg of nalbuphine (0.5 mL), and group F received 2.5 mL of 0.5% bupivacaine + 25 mcg fentanyl (0.5 mL). Both groups were compared for postoperative analgesia, onset and duration of both sensory and motor blockade, intraoperative hemodynamics, and side effects.

RESULTS

All demographic data, hemodynamic parameters, and side effects were not statistically significant among the two groups. However, other parameters, such as the mean duration of analgesia, which was 267.27 ± 172.099 minutes in group N and 161.35 ± 14.957 minutes in group F; meantime for the onset of sensory blockade, which was 3.94 ± 1.769 minutes in group N and 5.94 ± 0.929 minutes in group F; onset of complete motor blockade, which was 7.10 ± 1.858 minutes in group N and 11.61 ± 1.218 minutes in group F; duration of motor blockade, which was 182.57 ± 13.011 minutes in group N and 112.53 ± 7.389 minutes in group F; and mean time taken for two-segment regression, which was 118.20 ± 12.61 minutes in group N and 113.72 ± 8.84 minutes in group F, were all comparable between the two groups.

CONCLUSION

Nalbuphine was found to be more efficacious for prolongation of postoperative analgesia with better hemodynamic stability.

Role of tramadol as an adjuvant in ultrasound-guided serratus anterior muscle block for modified radical mastectomy - A randomized control trial

Background and Aims

Modified radical mastectomy (MRM) is associated with significant acute post-operative pain that may progress to chronic pain syndromes in 25-60% of patients. Serratus anterior muscle (SAM) block has proved to be an excellent analgesic option in patients undergoing MRM. Although many adjuvants have been utilized for the prolongation of analgesia, the role of tramadol in SAM has not been studied as yet. We hypothesize that the addition of tramadol to ropivacaine for SAM block may reduce morphine consumption in the post-operative period in patients undergoing elective MRM surgeries. The primary aim of the study was to compare cumulative post-operative morphine consumption over 24 h in patients receiving SAM block with or without tramadol. The secondary aims were to observe adverse events related to the procedure or medications. The other parameters recorded were non-invasive blood pressure (NIBP), pulse rate, respiratory rate, and nausea or vomiting.

Material and Methods

Patients scheduled to undergo MRM were randomly allocated by block randomization into two groups. The study group (Group T) received a SAM block with 0.25% ropivacaine (18 ml) with tramadol 100 mg while the control group (Group P) received a SAM block with 18 ml of 0.25% ropivacaine and 2 ml of saline. Patients were assessed for pain scores, analgesic requirement, time to first analgesic request, hemodynamic variables, and any side-effects at 30 min, 1 h, 4 h, 8 h, 12 h, and 24 h post-operatively.

Results

Cumulative morphine consumption over 24 h in the post-operative period was less in the group T (3.06 ± 1.53 mg vs 4.34 ± 1.53 mg; P 0.001). Time to the first analgesic requirement was more in group T (10.44 ± 5.04 h vs 6.11 ± 2.73 h; P < 0.001). Pain scores were significantly lower in the group T at all time points.

Conclusion

Tramadol, when used as an adjuvant to ropivacaine for SAM block reduces post-operative pain scores in the first 24 h and prolongs the time of first morphine requirement.

Highly Efficient Loading of Procaine on Water-Soluble Carbon Dots toward Long-Acting Anesthesia

Safe and efficient local anesthetic delivery carriers are crucial for long-term anesthesia and analgesics in clinical treatment. But currently, most of the local anesthetic carriers still have some disadvantages such as low drug-loading capacity, drug leakage, and potential side effects. Here, we report red-emissive carbon dots (Cys-CDs) synthesized by choosing cysteine and citric acid as precursors, which contain a large and intact sp2-domain with rich hydrophilic groups around the edge. The special structure of Cys-CDs is conducive to the efficient loading of procaine (PrC) via strong π-π stacking interactions. Based on the strong noncovalent interactions between them, the PrC loaded on Cys-CDs achieved slow release in vitro and had a long-lasting nerve blocking effect in vivo, which is 4-fold more than that of free PrC. More importantly, PrC/Cys-CDs do not cause any toxicity and inflammation during treatment owing to slow release of PrC and good water solubility of Cys-CDs, thus demonstrating the potential clinical application of CDs in long-lasting analgesia.

Effects of Ketamine and Tramadol As Adjuvants to Bupivacaine in Spinal Anesthesia for Unilateral Open Ovarian Cystectomy: A Randomized Controlled Trial

BACKGROUND

Spinal anesthesia offers numerous advantages and desirable features. However, it is associated with various side effects related to local anesthetic agents used. Reducing the dose of local anesthetic in spinal anesthesia can help minimize side effects but may lead to a diminished analgesic effect or failure of anesthesia. Therefore, adding an adjuvant may enhance the benefits while mitigating side effects.

OBJECTIVE

This study aimed to evaluate the effects of ketamine and tramadol as adjuvants to bupivacaine on the duration of spinal analgesia. The objectives were to compare the three groups and prove their analgesic effects, safety, and superiority. The primary outcomes were the duration of spinal analgesia, as well as the onset and duration of both sensory and motor blocks. Secondary outcomes included the heart rate, mean arterial pressure, and the incidence of undesired effects such as nausea, vomiting, sedation, shivering, and postoperative headache.

METHODS

In this double-blind randomized controlled trial, 120 female patients undergoing elective open unilateral ovarian cystectomy under spinal anesthesia were studied. The inclusion criteria included patients aged 16-45 years with a physical status classified as American Society of Anesthesiologists (ASA) class I and II. Patients were randomly allocated into three groups: group B (n=40) received only bupivacaine, group BK (n=40) received bupivacaine mixed with preservative-free ketamine, and group BT (n=40) received bupivacaine mixed with preservative-free tramadol.

RESULTS

The mean duration of spinal analgesia, measured in minutes, showed significant differences (P < 0.001) between group BK (165 ± 4) and group B (170 ± 5). There was also a significant difference between group BT (313 ± 8) and group B (170 ± 5) (P < 0.001). Additionally, significant differences were observed between group BK (165 ± 4) and group BT (313 ± 8) (P < 0.001).

CONCLUSION

The administration of 25 mg of ketamine and 25 mg of tramadol as adjuvants to bupivacaine in spinal anesthesia significantly affected the postoperative duration of analgesia. Tramadol prolonged the duration of spinal anesthesia, while ketamine shortened it. The use of both adjuvants did not result in undesired effects.

Perineural low dexamethasone dose as adjuvant in supraclavicular brachial plexus block for arteriovenous fistula creation in end stage renal disease: a randomized controlled trial

BACKGROUND AND AIMS

Dexamethasone as adjunct to local anesthetic solution improves the quality of brachial plexus block (BPB). However, evidence for its efficacy at low doses (< 4 mg) is lacking. This study was designed to evaluate the duration of analgesia attained with low dose dexamethasone as adjuvant to local anesthetic for creation of arteriovenous fistula (AVF) under BPB.

METHODS

Sixty-six patients scheduled for AVF creation were randomly allocated to receive either saline (control) or 2 mg dexamethasone, together with 0.5% ropivacaine and 0.2% lignocaine. The primary outcome was duration of analgesia, defined as time from performing the block to the first analgesic request. The secondary outcomes were time from injection to complete sensory block, time from injection to complete motor block, duration of motor block, postoperative analgesic consumption, and fistula patency at three months.

RESULTS

All the blocks were effective. In the group that received dexamethasone, the time to first analgesic request was significantly delayed (432 ± 43.8 minutes vs. 386.4 ± 40.2 minutes; p < 0.01). The onset of sensory and motor blockade occurred faster in dexamethasone group and overall analgesic consumption was also reduced. However, dexamethasone addition did not prolong the duration of motor block. There was no statistically significant difference in the patency of fistulas between the two groups at three months. (p = 0.34).

CONCLUSION

Addition of low-dose perineural dexamethasone to local anesthetic solution significantly prolonged the duration of analgesia. Further trials are warranted to compare the adverse effects between dexamethasone doses of 4 mg and lower.

Extrapleural infusion of levobupivacaine versus levobupivacaine-sufentanil-adrenaline after video-assisted thoracoscopic surgery (VATS): A randomised controlled trial

BACKGROUND

Peripheral blocks are increasingly used for analgesia after video-assisted thoracic surgery (VATS). We hypothesised that addition of sufentanil and adrenaline to levobupivacaine would improve the analgesic effect of a continuous extrapleural block.

METHODS

We randomised 60 patients undergoing VATS to a 5-mL h-1 extrapleural infusion of levobupivacaine at 2.7 mg mL-1 (LB group) or levobupivacaine at 1.25 mg mL-1 , sufentanil at 0.5 μg mL-1 , and adrenaline at 2 μg mL-1 (LBSA group). The primary outcome was the cumulative morphine dose administered as patient-controlled analgesia (PCA-morphine) at 48 and 72 h. The secondary outcomes were pain according to numerical rating scale (NRS) at rest and after two deep breaths twice daily, peak expiratory flow (PEF) daily, quality of recovery (QoR)-15 score at 1 day and 3 weeks postoperatively, serum levobupivacaine concentrations at 1 h after the start and at the end of the intervention, and adverse events.

RESULTS

At 48 h, the median cumulative PCA-morphine dose for the LB group was 6 mg (IQR, 2-10 mg) and for the LBSA group 7 mg (IQR, 3-13.5 mg; p = .378). At 72 h, morphine doses were 10 mg (IQR, 3-22 mg) and 12.5 mg (IQR, 4-21 mg; p = .738), respectively. Median NRS score at rest and after two deep breaths was 3 or lower at all time points for both treatment groups. PEF did not differ between groups. Three weeks postoperatively, only the LB group returned to baseline QoR-15 score. The LB group had higher, but well below toxic, levobupivacaine concentrations at 48 and 72 h. The incidence of nausea, dizziness, pruritus and headache was equally low overall.

CONCLUSION

For a continuous extrapleural block, and compared to plain levobupivacaine at 13.5 mg h-1 , levobupivacaine at 6.25 mg h-1 with addition of sufentanil and adrenaline did not decrease postoperative morphine consumption. The levobupivacaine serum concentrations after 48 and 72 h of infusion were well below toxic levels, therefore our findings support the use of the maximally recommended dose of levobupivacaine for a 2- to 3-day continuous extrapleural block.

How Does the Addition of Dexamethasone to a Brachial Plexus Block Change Pain Patterns After Surgery for Distal Radius Fractures? A Randomized, Double-blind Study

BACKGROUND

Although brachial plexus block in volar plating surgery for distal radius fractures is reportedly associated with lower postoperative pain scores, rebound pain has been reported to occur after the initial block wears off. Dexamethasone can be used in multimodal strategies for antiemesis and to control pain postoperatively. Although prior studies have suggested that anesthesia can be prolonged by adding dexamethasone to regional blocks, no randomized trials we are aware of have ascertained whether doing so will make a clinically important difference in pain after surgery for distal radius fractures.

QUESTIONS/PURPOSES

Do patients who receive supplemental dexamethasone in a brachial plexus block for volar plating of unstable distal radius fractures have (1) better pain scores at 4, 8, 24, and 48 hours postoperatively than patients who have not received dexamethasone, and (2) lower fentanyl consumption and administration of antiemetic drugs without change in serum blood glucose, as well as a longer analgesic duration from the block after surgery than patients who have not received dexamethasone?

METHODS

This randomized, double-blind trial included 69 patients undergoing surgery for distal radius fractures under ultrasound-guided supraclavicular brachial plexus blocks who were randomly allocated into two groups: a nondexamethasone group receiving a brachial plexus block with 0.5% ropivacaine and a dexamethasone group receiving 0.5% ropivacaine and 5 mg of dexamethasone. Thirty-four patients were allocated to the dexamethasone group and 35 were allocated to the nondexamethasone group. Nine patients (four in the dexamethasone group and five in the nondexamethasone group) were excluded after randomization because local anesthetics were used during their surgical procedures owing to an incomplete block or they requested patient-controlled analgesia after surgery. The treatment groups did not differ in any important ways, including age, gender, BMI, hand dominance, and AO/Orthopaedic Trauma Association classification. All patients received the same surgical procedure and perioperative care protocol, except for the injected agents during their brachial plexus block. The primary outcome was postoperative pain, evaluated using a 10-mm VAS at 4, 8, 12, 24, and 48 hours after surgery. The minimum clinically important difference for the VAS score was 2 of 10 points. Secondary outcome variables included fentanyl administration as a rescue analgesic, the number of patients receiving antiemetic medications because of fentanyl administration, and the duration of brachial plexus block. Serum blood glucose was measured 1 day before, immediately after, and 24 hours after surgery. Patients, surgeons, and outcome assessors were blinded to treatment allocation.

RESULTS

The only clinically important between-group difference in VAS pain scores was at 8 hours, favoring the group that received dexamethasone over the group that did not (1.9 ± 1.6 versus 4.7 ± 2.7; mean difference -2.8 [95% CI -3.9 to -1.6]; p < 0.001). After brachial plexus block, the most severe pain score in both groups was reported at 12 hours postoperatively and gradually diminished over time. There was no between-group difference in fentanyl use between those who received dexamethasone and those who did not (21 ± 38 mcg versus 31 ± 29 mcg; mean difference -10 [95% CI -27.4 to 7.4]; p = 0.26). Furthermore, the use of antiemetics did not differ between the groups (27% [eight of 30] versus 37% [11 of 30]; odds ratio 1.6 [95% CI 0.5 to 4.8]; p = 0.41). Baseline and 24-hour postoperative serum blood glucose level did not differ between the groups. However, the immediately postoperative serum blood glucose level was higher in the dexamethasone group than in the nondexamethasone group (121 ± 29 versus 104 ± 20; mean difference 16 [95% CI 3.3 to 28.8]; p = 0.02). The brachial plexus block duration was 3 hours longer (95% CI 0.8 to 5.2 hours) in the dexamethasone group than that in the nondexamethasone group (11 ± 5 hours versus 8 ± 3 hours; p = 0.01).

CONCLUSION

The postoperative pain level in patients who received supplemental dexamethasone in a regional block was not clinically different from that of patients who received conventional brachial plexus block anesthesia when undergoing volar plating for distal radius fractures. However, patients who received a brachial plexus block with dexamethasone experienced slight prolongation of their block and decrease in pain 8 hours after surgery.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Implications of different analgesic models on inflammatory markers after laparoscopic cholecystectomy

BACKGROUND

Despite its advantages, laparoscopic surgery causes significant shoulder and abdominal pain in 35%-80% of patients. The cause of post-laparoscopy pain is not fully understood, but it is assumed to be a multifactorial referred pain.

AIM OF THE STUDY

To evaluate the effect of different analgesia techniques on post-laparoscopic pain and inflammatory markers.

METHODS

Patients scheduled for elective laparoscopic cholecystectomy were randomly assigned to receive local hepatic and right subdiaphragmatic infiltration of one of the 4 study drug combinations: Group 1 (G1) received 20 ml bupivacaine 0.25%; Group 2 (G2) received 20 ml bupivacaine 0.25% +3 mg morphine sulphate; Group 3 (G3) received 20 ml bupivacaine 0.25% + 3 mg morphine sulphate +200 µg/kg ketamine; and Group 4 (G4) received 20 ml isotonic saline as the control group.

RESULTS

In G3, both shoulder pain on the verbal numerical rating scale and inflammatory marker levels were lower compared with the other groups. The highest levels of inflammatory markers were observed in the control group; this difference was statistically significant. No side effects or complications were observed in the study groups.

CONCLUSION

The addition of ketamine and morphine to bupivacaine for hepatic and subdiaphragmatic infiltration produced good analgesia and reduced inflammatory marker levels after laparoscopic cholecystectomy.

Effect of intravenous dexamethasone on the duration of hyperbaric bupivacaine spinal anesthesia in lower abdominal surgery, Randomized controlled trial

BACKGROUND

The purpose of this study was to investigate the effect of intravenous (IV) dexamethasone on the duration of hyperbaric bupivacaine spinal anesthesia.

METHODS

Two hundred patients between the ages of 18 and 60, of both sexes with ASA I- II classification scheduled for lower abdominal surgery under spinal anesthesia using hyperbaric bupivacaine 0.5% were randomly divided into two groups: the dexamethasone group (Dexa group) and the control group, with 100 patients in each group. Before the administration of spinal anesthesia, the Dexa group received an intravenous infusion of 8 mg dexamethasone in 500 mL normal saline, while the control group received 500 mL normal saline only. The primary outcome of this study was to assess the effect of IV dexamethasone on the regression of hyperbaric bupivacaine spinal anesthesia. Secondary outcome measures included the total duration of sensory and motor blocks, VAS score, time of first analgesic request, total analgesic consumption within the first 24 h, and the occurrence of any side effects.

RESULTS

The Dexa group had significantly delayed onset of 2 dermatomes regression (P < 0.001) compared to the control group. Additionally, the Dexa group had significantly longer duration of both sensory block (P = 0.01) and motor block (P < 0.001). The Dexa group had significantly longer duration until the first postoperative analgesic request (P < 0.001) and a lower incidence of side effects compared to the control group.

CONCLUSION

Although the intravenous administration of dexamethasone had a limited effect on the duration of hyperbaric bupivacaine spinal anesthesia, it improved postoperative VAS scores compared to the control group and decreased overall postoperative analgesic consumption. Therefore, it can be considered a valuable addition to postoperative multimodal analgesia strategies, aiming to minimize total analgesic consumption.

CLINICAL TRIAL REGISTRATION

ID: NCT04778189 (2/3/2021).

Magnesium Sulfate in Pediatric Abdominal Cancer Surgery: Safety and Efficacy in Ultrasound-Guided Transversus Abdominis Plane (US-TAP) Block in Conjugation with Levobupivacaine

Purpose

Magnesium sulfate (MgSO4) may enhance the effects of local anesthetics when used as an adjuvant in peripheral nerve blocks. Our objective was to evaluate efficiency and safety of utilizing MgSO4 alongside levobupivacaine in bilateral ultrasound-guided transversus abdominis plane (US-TAP) block for postoperative pain in pediatric cancer patients who underwent abdominal surgery.

Methodology

A randomized double-blinded controlled trial at South Egypt Cancer Institute, Assiut University, Assiut, Egypt, included that 40 pediatric patients with Wilms' tumor or neuroblastoma were randomly allocated to get bilateral (US-TAP) block and divided into two groups; M group: received US-TAP with 0.6 mL/kg levobupivacaine 0.25% + 2 mg/kg MgSO4 and C group: received with 0.6 mL/kg levobupivacaine 0.25% only. FLACC scores (Face, Leg, Activity, Cry, Consolability) were used to evaluate post-operative pain, first analgesic request, total analgesic consumption, adverse effects, as well as hemodynamics were monitored for 24 h and recorded at time points (2, 4, 6, 8, 12, 18, and 24h). Parent's satisfaction at discharge, also, was evaluated.

Results

FLACC score in M group was significantly lower than in C group from 4 h to 24 h with the first analgesic request being longer (15.95 ± 1.99 vs 7.70 ± 0.80 (h); p < 0.001) and lower total analgesic consumption (231.75 ± 36.57 vs 576.00 ± 170.71 (mg); p < 0.001) when comparing M group to C group, respectively. Both groups had insignificant differences regarding hemodynamics, parent satisfaction, postoperative agitation, and side effects except vomiting occurred in two patients in the C group and one patient in the M group.

Conclusion

We conclude that adding magnesium sulphate as an adjuvant to local anaesthetic in US-TAP block for pain management in pediatric abdominal cancer surgeries resulted in better and longer analgesia, with less consumption of rescue analgesics with no serious side effects.

Comparison of conventional and robotic knee arthroplasty results: A retrospective observational study

OBJECTIVE

This study aimed to determine whether a standard anesthetic protocol consisting of combined spinal epidural anesthesia (CSEA) in conjunction with controlled hypotensive anesthesia (CHA), which was used for conventional total knee arthroplasty (cTKA), could provide equally effective anesthetic conditions for robotic total knee arthroplasty (rTKA).

METHODS

Data were collected from the medical records of 113 patients (median age=67 years; age range=55-84) who underwent elective unilateral cTKA (n=52) or rTKA (n=61) without a tourniquet from 2021 to 2023. The primary outcome measure was the rate of patients whose anesthetic method did not provide adequate motor and sensory block during the surgery and had to be converted to general anesthesia. The secondary outcome measure was to compare perioperative variables, including pain scores, analgesic consumption, blood loss, transfusions, and complications.

RESULTS

In 6 patients (11.5%) in group rTKA, it was required to convert CSEA to general anesthesia at 160-180 minutes due to the pain at the operative knee and/or to the movement of the operative leg during surgery compared to none / zero in group cTKA (P=.008). Motor and sensory blocks terminated earlier than the total surgery time in those patients. Mean total surgery time was significantly higher in group rTKA than in group cTKA (151.25 ± 24.51 (120-240) minutes vs. 116.72 ± 4.99 (105-125) minutes, P < .001). Total surgery times tended to decrease gradually in group rTKA after the 11th case, indicating a learning curve for surgical performance. Conversion to general anesthesia was required only in 1 patient after the 11th case compared to the previous 5 patients. Mean pain scores and rescue analgesic consumption were higher in group rTKA at postoperative 0 hour and between 0 and 4 hours (P < .05) but similar at the following time points (P > .05). Blood loss, transfusion, and complication rates were similar (P > .05). Hospital discharge times were higher in group rTKA (P < .05).

CONCLUSION

Although our standard CSEA protocol failed due to the regression of motor and sensory block during surgery in 11.5% of patients in rTKA, the CSEA technique combined with controlled hypotensive anesthesia provided similar anesthetic conditions in the remaining patients in group rTKA as in group cTKA. The CSEA may be considered an effective and safe anesthetic method for rTKA if interventions are applied to extend the duration of the CSEA for this novel surgical technique.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

New advances in clinical application of neostigmine: no longer focusing solely on increasing skeletal muscle strength

Neostigmine is a clinical cholinesterase inhibitor, that is, commonly used to enhance the function of the cholinergic neuromuscular junction. Recent studies have shown that neostigmine regulates the immune-inflammatory response through the cholinergic anti-inflammatory pathway, affecting perioperative neurocognitive function. This article reviews the relevant research evidence over the past 20 years, intending to provide new perspectives and strategies for the clinical application of neostigmine.

"Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part B (Nerve Injury Types, Mechanisms, and Pathogenesis)

Selander emphatically said, "Handle these nerves with care," and those words still echo, conveying a loud and clear message that, however rare, peripheral nerve injury (PNI) remains a perturbing possibility that cannot be ignored. The unprecedented nerve injuries associated with peripheral nerve blocks (PNBs) can be most tormenting for the unfortunate patient and a nightmare for the anesthetist. Possible justifications for the seemingly infrequent occurrences of PNB-related PNIs include a lack of documentation/reporting, improper aftercare, or associated legal implications. Although they make up only a small portion of medicolegal claims, they are sometimes difficult to defend. The most common allegations are attributed to insufficient informed consent; preventable damage to a nerve(s); delay in diagnosis, referral, or treatment; misdiagnosis, and inappropriate treatment and follow-up care. Also, sufficient prospective studies or randomized trials have not been conducted, as exploring such nerve injuries (PNB-related) in living patients or volunteers may be impractical or unethical. Understanding the pathophysiology of various types of nerve injury is vital to dealing with them further. Processes like degeneration, regeneration, remyelination, and reinnervation can influence the findings of electrophysiological studies. Events occurring in such a process and their impact during the assessment determine the prognosis and the need for further interventions. This educational review describes various types of PNB-related nerve injuries and their associated pathophysiology.

Comparison between the effects of epidural lidocaine, tramadol, and lidocaine-tramadol on postoperative pain in cats undergoing elective orchiectomy

BACKGROUND

In veterinary clinical practice, orchiectomy is one of the most common surgical procedures for cats and is performed mainly in young animals. The purpose of this study was to compare three different epidural (EP) analgesic protocols used in cats undergoing orchiectomy in order to determine which protocol resulted in superior outcomes in terms of perioperative analgesia. Twenty-one client-owned male cats were premedicated with a combination of dexmedetomidine (10 µg/kg) and midazolam (0.2 mg/kg) injected intramuscularly. Anesthesia was induced intravenously with propofol. Cats were randomly divided in three treatment groups of seven animals each: Group L received EP lidocaine (2 mg/kg), Group T received EP tramadol (1 mg/kg), and Group LT received EP lidocaine (2 mg/kg) plus tramadol (1 mg/kg). The post-operative pain level was assessed using two different scales: the Glasgow Composite Measure Pain Scale-Feline (CMPS-F) and the Feline Grimace Scale (FGS). Rescue analgesia was administered when the CMPS-F total score was ≥5 or the FGS total score was ≥4.

RESULTS

No adverse effects related to tramadol or lidocaine were observed. Based on post-operative pain assessments, significant differences between groups were observed according to both pain scoring systems. In particular, in Group LT, the CMPS-F and FGS scores decreased significantly in the first six hours following castration.

CONCLUSIONS

Based on our results, EP lidocaine plus tramadol provided the best post-operative analgesic effects in cats submitted to orchiectomy lasting 6 h and could also be a choice to consider for longer surgical procedures.

A comparative study on the effect of dopamine vs phenylephrine in improving the cutaneous analgesic effect of mexiletine in rats

BACKGROUND

The present study aimed to compare the effects of the combined administration of two adjuvants, dopamine and phenylephrine, on the cutaneous analgesic effect and duration of mexiletine in rats.

METHODS

Nociceptive blockage was evaluated by the inhibition of response to skin pinpricks in rats via the cutaneous trunci muscle reflex (CTMR). After subcutaneous injection, the analgesic activities of mexiletine in the absence and presence of either dopamine or phenylephrine were assessed. Each injection was standardized into 0.6 ml with a mixture of drugs and saline.

RESULTS

Subcutaneous injections of mexiletine successfully induced dose-dependent cutaneous analgesia in rats. The results revealed that rats injected with 1.8 μmol mexiletine exhibited 43.75% blockage (%MPE), while rats injected with 6.0 μmol mexiletine showed 100% blockage. Co-application of mexiletine (1.8 or 6.0 μmol) with dopamine (0.06, 0.60, or 6.00 μmol) elicited full sensory block (%MPE). Sensory blockage ranged from 81.25% to 95.83% in rats injected with mexiletine (1.8 μmol) and phenylephrine (0.0059 or 0.0295 μmol), and complete subcutaneous analgesia was observed in rats injected with mexiletine (1.8 μmol) and a higher concentration of phenylephrine (0.1473 μmol). Furthermore, mexiletine at 6.0 μmol completely blocked nociception when combined with any concentration of phenylephrine, while 0.1473 μmol phenylephrine alone exhibited 35.417% subcutaneous analgesia. The combined application of dopamine (0.06/0.6/6 μmol) and mexiletine (1.8/6 μmol) resulted in increased %MPE, complete block time, full recovery time, and AUCs compared to the combined application of phenylephrine (0.0059 and 0.1473 μmol) and mexiletine (1.8/6 μmol) (p < 0.001).

CONCLUSION

Dopamine is superior to phenylephrine in improving sensory blockage and enhancing the duration of nociceptive blockage by mexiletine.

Ketamine versus midazolam as an adjuvant to peribulbar block using a single inferonasal injection in patients undergoing vitreoretinal surgery: A randomized controlled trial

INTRODUCTION AND OBJECTIVES

This study aimed to assess the safety and efficacy of midazolam and ketamine as adjuvants to the peribulbar block in vitreoretinal surgeries.

PATIENTS AND METHODS

This randomized controlled trial included 93 adult patients undergoing vitreoretinal surgeries performed with peribulbar anaesthesia. Patients were randomly allocated to 3 groups (31 participants each): control (standard anaesthetic mixture), midazolam (standard mixture + midazolam), and ketamine (standard mixture + ketamine). The primary outcomes were onset of globe akinesia and duration of analgesia. Secondary outcomes were duration of motor blockade, onset of corneal anaesthesia and lid akinesia, and changes in vital data (blood pressure, oxygen saturation, and pulse rate).

RESULTS

The ketamine group vs. the control and midazolam groups showed the most rapid onset of lid and globe akinesia (p < 0.001) and corneal anaesthesia (0.7 ± 0.2 vs. 1.5 ± 0.5 and 1.2 ± 0.4, respectively; p < 0.001) and the longest duration of both analgesia (3.7 ± 0.6 vs. 2.3 ± 0.4 and 3.1 ± 0.6, respectively; p < 0.001) and akinesia (3.8 ± 0.5 vs. 3.0 ± 0.4, and 3.7 ± 0.5, respectively; p < 0.001). The midazolam group showed better outcomes than controls, but the drug was less effective than ketamine. There were no significant differences in vital data among groups (p > 0.05).

CONCLUSIONS

Ketamine is an effective adjuvant for peribulbar blockade. It enhances both motor and sensory blockade by hastening onset and prolonging duration. These effects are desirable in lengthier ophthalmic procedures such as vitreoretinal surgeries. The effects of ketamine were superior to those of midazolam.

Naphazoline and oxymetazoline are superior to epinephrine in enhancing the cutaneous analgesia of lidocaine in rats

This study observed the cutaneous analgesic effect of adrenergic agonists when combined with lidocaine. We aimed at the usefulness of four adrenergic agonists and epinephrine as analgesics or as tools to prolong the effect of local anesthetics using a model of cutaneous trunci muscle reflex (pinprick pain) in rats. We showed that subcutaneous four adrenergic agonists and epinephrine, as well as the local anesthetic bupivacaine and lidocaine, developed a concentration-dependent cutaneous analgesia. The rank order of the efficacy of different compounds (ED₅₀ ; median effective dose) was epinephrine [0.013 (0.012-0.014) μmol] > oxymetazoline [0.25 (0.22-0.28) μmol] > naphazoline [0.42 (0.34-0.53) μmol] = bupivacaine [0.43 (0.37-0.50) μmol] > xylometazoline [1.34 (1.25-1.45) μmol] > lidocaine [5.86 (5.11-6.72) μmol] > tetrahydrozoline [6.76 (6.21-7.36) μmol]. The duration of full recovery caused by tetrahydrozoline, oxymetazoline, or xylometazoline was greater (P < 0.01) than that induced via epinephrine, bupivacaine, lidocaine, or naphazoline at equianesthetic doses (ED₂₅ , ED₅₀ , and ED₇₅ ). Co-administration of lidocaine (ED₅₀ ) with four adrenergic agonists or epinephrine enhanced the cutaneous analgesic effect. We observed that four adrenergic agonists and epinephrine induce analgesia by themselves, and such an effect has a longer duration than local anesthetics. Co-administration of lidocaine with the adrenergic agonist enhances the analgesic effect, and the cutaneous analgesic effect of lidocaine plus naphazoline (or oxymetazoline) is greater than that of lidocaine plus epinephrine.

Beta-blocker carteolol and oxprenolol produce cutaneous analgesia in response to needle pinpricks in the rat

BACKGROUND

This present study was undertaken to determine whether beta-blockers produce the cutaneous analgesic effect, comparing them with the long-acting local anesthetic bupivacaine.

METHODS

Using a rat model of infiltrative cutaneous analgesia, the effect of 5 beta-blockers (oxprenolol, carteolol, butaxamine, metoprolol, and acebutolol) and bupivacaine was compared and eventually combined with epinephrine.

RESULTS

Among 5 beta-blockers, oxprenolol exhibited the most potent and the longest duration of cutaneous analgesia. In dose-response studies, the rank order of efficacy (ED₅₀ [50% effective dose]) was bupivacaine (0.40 [0.35-0.47] μmol) > oxprenolol (2.33 [2.06-2.64] μmol) > carteolol (4.86 [4.27-5.53] μmol) (p< 0.01). Carteolol provoked a longer duration of analgesia (p< 0.01) than oxprenolol or bupivacaine on an equipotent basis (ED₂₅, ED₅₀, and ED₇₅). Adding epinephrine 1:200,000 to drug preparations (carteolol, oxprenolol, and bupivacaine) at ED₉₅ had a peripheral action in prolonging the duration of action.

CONCLUSIONS

Oxprenolol and carteolol had greater potencies and longer durations of cutaneous analgesia than butaxamine, metoprolol, and acebutolol. Oxprenolol produced a similar duration of action when compared to bupivacaine, while carteolol had a greater duration of action than bupivacaine. Cutaneous analgesia of oxprenolol (or carteolol) plus adrenaline was greater than that of bupivacaine plus adrenaline.

Evaluation of magnesium sulfate as an adjuvant in sub-Tenon anesthesia for cataract surgery: A prospective, randomized controlled trial

Purpose

To evaluate the efficacy, safety, and satisfaction for the use of adjuvant; magnesium sulfate (MgSO4) in sub-Tenon anesthesia for cataract surgery.

Methods

This single centered randomized, double blind trial was held in 2021 after approval of ethical committee at the Eye Hospital, Riyadh, Saudi Arabia. Cataract patients to be operated using local anesthesia were randomly assigned to two groups; Group magnesium sulfate (MS) received 50 mg/0.5 ml of magnesium sulfate and Group normal saline (NS) received 0.5 ml of normal saline added to the standard mixture, respectively. Absence of eyelid dropping and akinesia of the globe at different time after anesthesia were considered as ineffective anesthesia. The age and sex-adjusted generalized estimating equation (GEE) analysis was carried out. Complications, patient's and surgeon's satisfaction were also compared.

Results

Each group had 100 cataract patients. Effectiveness of block was not significantly different in two groups (adjusted odds ratio, 0.90; 95% confidence interval [CI], 0.62, 1.31; P = 0.594). The likelihood of "no eye-opening" significantly increased with time (adjusted odds ratio, 1.26; 95% CI, 1.18-1.34; P < 0.001). Subconjunctival bleeding was significantly higher in the MS versus NS Group (36 of 98 [36.7%] vs. 11 of 102 [10.8%], P < 0.001). Chemosis was not significantly different between the groups (P = 0.95). Patient's satisfaction score was very good (9/10) but slightly higher in NS group than MS (P = 0.001) while surgeon's satisfaction score was similar in both groups (P = 0.149).

Conclusions

Although safe, adding 50 mg of magnesium sulfate did not improve the effect of sub-Tenon anesthesia for cataract surgery. Risk of subconjunctival bleeding was higher in cataract patients operated using MgSO4 compared to those managed with the conventional sub-Tenon anesthetic.

N(Omega)-nitro-l-arginine methyl ester potentiates lidocaine analgesic and anaesthetic effect in rats

OBJECTIVES

The purpose of the experiment was to study the effect of L-NAME (N(Omega)-nitro-L-arginine methyl ester) and its cotreatment with lidocaine on the spinal block and infiltrative cutaneous analgesia.

METHODS

The quality of cutaneous analgesia was examined by the block of the cutaneous trunci muscle reflexes following needle stimuli in the rat. Spinal anaesthetic potency was assessed by measuring three neurobehavioral examinations of nociceptive, proprioceptive and motor function following intrathecal injection in the rat.

KEY FINDINGS

L-NAME (0.6, 6 and 60 nmol) when cotreatment with lidocaine (ED50) produced dose-related cutaneous analgesia. Coadministration of L-NAME (0.6 μmol) with lidocaine intensified (P < 0.01) and prolonged (P < 0.001) cutaneous analgesia, whereas subcutaneous L-NAME (0.6 μmol) and saline did not provoke cutaneous analgesic effects. Adding L-NAME (2.5 μmol) to lidocaine intrathecally prolonged spinal sensory and motor block (P < 0.01), while intrathecal L-NAME (2.5 μmol) or 5% dextrose (vehicle) produced no spinal block.

CONCLUSIONS

L-NAME at 60 nmol (the minimum effective dose) increases and prolongs the effect of cutaneous analgesia of lidocaine. L-NANE at an ineffective dose potentiates lidocaine analgesic and anaesthetic effects.

Preparation of Ropivacaine Encapsulated by Zeolite Imidazole Framework Microspheres as Sustained-Release System and Efficacy Evaluation

The management of persistent postoperative pain still remains a clinical challenge currently. Although ropivacaine (RVC) is widely used for postoperative analgesia as a local anesthetic, the short half-life makes it difficult to achieve the desired duration of analgesia. Herein, a RVC sustained-release microspheres encapsulated by zeolite imidazole framework-8 (RVC@ZIF-8) was synthesized for the first time, which prolonged the sustained-release of RVC and decreased the resulting drug toxicity. RVC can continuously release in vitro for at least 96 h with high drug loading of 30.6 % and RVC@ZIF-8 had excellent biocompatibility and low cytotoxicity. In sciatic nerve block model, the sensory block time of RVC@ZIF-8 was significantly prolonged compared with RVC, achieving more than 72 h post injection and no inflammation or lesion were found. Based on high drug loading, ideal sustained-release and superior biological safety, RVC@ZIF-8 will be a novel delivery material for local anesthetic with potential application.

The potential value of exosomes as adjuvants for novel biologic local anesthetics

The side effects of anesthetic drugs are a key preoperative concern for anesthesiologists. Anesthetic drugs used for general anesthesia and regional blocks are associated with a potential risk of systemic toxicity. This prompted the use of anesthetic adjuvants to ameliorate these side effects and improve clinical outcomes. However, the adverse effects of anesthetic adjuvants, such as neurotoxicity and gastrointestinal reactions, have raised concerns about their clinical use. Therefore, the development of relatively safe anesthetic adjuvants with fewer side effects is an important area for future anesthetic drug research. Exosomes, which contain multiple vesicles with genetic information, can be released by living cells with regenerative and specific effects. Exosomes released by specific cell types have been found to have similar effects as many local anesthetic adjuvants. Due to their biological activity, carrier efficacy, and ability to repair damaged tissues, exosomes may have a better efficacy and safety profile than the currently used anesthetic adjuvants. In this article, we summarize the contemporary literature about local anesthetic adjuvants and highlight their potential side effects, while discussing the potential of exosomes as novel local anesthetic adjuvant drugs.

Butorphanol as an Adjuvant to Ropivacaine for Adductor Canal Blocks in Total Knee Arthroplasty Patients: A Randomized, Double, Blind Study

Background

The objective of this study was to observe the effects of butorphanol as an adjuvant to ropivacaine for the adductor canal block (ACB) on postoperative analgesia in patients undergoing total knee arthroplasty (TKA).

Methods

Seventy-four patients undergoing TKA were included and randomly divided into two groups: Group BR received 20 ml of 0.33% ropivacaine plus 1 mg butorphanol and Group R received 20 ml of 0.33% ropivacaine plus 1 ml normal saline for ultrasound-guided adductor canal blocks. The primary outcomes were the duration of the sensory block and the pain visual analogue scale (VAS), and secondary outcomes included the number of PCIA attempts (patient-controlled intravenous analgesia) and the time to first pressing and rescue analgesia. Other outcomes included knee active range of motion (ROM), quadriceps strength, the time to first mobilization, the duration of postoperative hospital stay, Knee Society Score (KSS), and postoperative complications.

Results

Since two patients in each group rejected postoperative assessments, 35 patients were included in each group. Compared with Group R, Group BR had longer duration of sensory blocks (18.42 ± 3.46 vs. 15.36 ± 2.29 h, p < 0.01) and lower postoperative pain scores within 24 hours at rest and within 12 hours with activity (p < 0.01). The number of PCIA attempts decreased within 48 hours after surgery (4.5 ± 1.2 vs. 7.8 ± 1.5 times, p < 0.01), and the time to first pressing was later (20.31 ± 2.59 vs. 16.25 ± 2.31 h, p < 0.01). In addition, Group BR had bigger knee ROM at within 24 hours after the operation than Group R (68.37 ± 4.70°vs. 59.21 ± 6.41,85.67 ± 5.17 vs. 74.37 ± 4.68°, 97.62 ± 5.43 vs. 84.18 ± 4.49°, p < 0.01). There was no significant difference between the two groups (p > 0.05) in terms of rescue analgesia, quadriceps strength, the time to first mobilization, the duration of postoperative hospital stay, the KSS function scores, and postoperative complications.

Conclusions

Butorphanol plus ropivacaine ultrasound-guided adductor canal block can prolong the duration of sensory block, relieve early postoperative pain, and improve the range of motion of the knee joint, without affecting the occurrence of postoperative complications. Name of the Registry. Chinese Clinical Trial Registry. Trial Registration Number. ChiCTR2100041859. URL of Trial Registry Record. http://www.chictr.org.cn/edit.aspx?pid=119731&htm=4. Date of Registration. 08/01/2021 0:00:00.

Corrected and Republished: Impacts of intrathecal fentanyl on the incidence of postoperative nausea/vomiting: Systematic review and meta-analysis of randomized studies

Post-operative nausea and vomiting (PONV) is an event of multifactorial origin with an incidence of 30% in the general population. Opioids such as fentanyl are being used as adjuvant to local anesthetic for its antiemetic effect. In this context, with this study we aimed to evaluate the impact of spinal fentanyl as an adjuvant on the incidence of PONV compared with a placebo, and shivering. A systematic search of randomized controlled trials that evaluated the use of spinal fentanyl in the prevention of PONV and shivering was conducted in different databases, of which 32 studies met the inclusion criteria. A total of 2116 patients scheduled for various surgeries, including cesarean section, orthopedic surgery in the lower limb, hysterectomy, and transurethral resection of the prostate, were included in the final analysis. The meta-analysis estimated the relative risk of incidence of PONV in the first 24 hours after surgery and secondary outcomes included the shivering symptom. The use of intrathecal fentanyl was associated with lower incidence of PONV, but not statistically significant when compared to the placebo (RR: 0.74 CI95%: 0.55-1.01 P = 0.06). Subgroup analysis showed a statistically significant reduction in PONV incidences with lower doses between 10 and 15 μg (RR: 0.44 CI95%: 0.35-0.55 P < 0.00001, I2 = 0%) but not with higher doses 20-25 μg. Secondary outcomes showed a decrease in incidence with the use of fentanyl vs the placebo (RR: 0.49, CI95% 0.33-0.72 P = 0.0003). Current evidence shows that the use of spinal fentanyl decreases the incidence of PONV, an effect favored using low doses.

Efficacy of Ketamine versus Magnesium Sulphate as Adjuvants to Levobupivacaine in Ultrasound Bilevel Erector Spinae Block in Breast Cancer Surgery (a Double-Blinded Randomized Controlled Study)

Purpose

Breast surgeons seek simple, safe, effective, and novel regional anesthesia techniques for postoperative analgesia. Erector spinae plane (ESP) block is a new ultrasound-guided technique. We aimed to explore the analgesic effect of adding ketamine and magnesium sulfate as adjuvants to levobupivacaine in ESP.

Patients and Methods

Sixty female patients (aged 18-60 years) with breast cancer, weighing 50-90 kg who were scheduled for modified radical mastectomy (MRM) were randomly allocated into three groups (20 patients each) to receive an ESP block with 20 mL 0.25% levobupivacaine with adjuvants according to the following groups: group C: levobupivacaine; group K: levobupivacaine + 2 mg/kg ketamine; and group M: levobupivacaine + 2 mg/kg magnesium sulfate. The block was administered preoperatively before anesthesia induction. Postoperatively, hemodynamics, visual analog scale scores, the first request for analgesia, total analgesic consumption, and side effects were observed for 48 hours.

Results

The total amount of Morphine rescue analgesia was significantly lower in groups M (7.00 ± 0.61 mg) and K (7.50 ± 0.58 mg) than in group C (14.40 ± 3.47 mg) during the first 48 h postoperatively. Nine (45%) patients in group M and 13 (65%) patients in K, compared with 20 (100%) patients in group C, requested analgesia. The time to first request of analgesia was significantly longer in groups M (30 h) and K (24 h) than in group C (7 h). No hemodynamic changes or serious side effects were observed.

Conclusion

Magnesium sulphate and ketamine seem to be both effective adjuvants to levobupivacaine in ESP blocks for postoperative analgesia in patients undergoing MRM, with slightly better analgesia provided by magnesium sulphate.

The effects of magnesium sulfate added to epidurally administered local anesthetic on postoperative pain: a systematic review

BACKGROUND

This study evaluated the efficacy of epidurally administered magnesium associated with local anesthetics on postoperative pain control.

METHODS

The study protocol was registered in PROSPERO as CRD42021231910. Literature searches were conducted on Medline, Cochrane, EMBASE, CENTRAL, and Web of Science for randomized controlled trials comparing epidural administration of magnesium added to local anesthetics for postoperative pain in elective surgical adult patients. Primary outcomes were the time to the first Postoperative (PO) Analgesic Request (TFAR), 24-hour postoperative opioid consumption, and Visual Analog Scale (VAS) scores at the first six and 24 postoperative hours. Secondary outcomes included Postoperative Nausea and Vomiting (PONV), pruritus, and shivering. Quality of evidence was assessed using GRADE criteria.

RESULTS

Seventeen studies comparing epidural were included. Effect estimates are described as weighted Mean Differences (MD) and 95% Confidence Intervals (95% CI) for the main outcomes: TFAR (MD = 72.4 min; 95% CI = 10.22-134.58 min; p < 0.001; I² = 99.8%; GRADE: very low); opioid consumption (MD = -7.2 mg (95% CI = -9.30 - -5.09; p < 0.001; I² = 98%; GRADE: very low). VAS pain scores within the first six PO hours (VAS) (MD = -1.01 cm; 95% CI = -1.40-0.64 cm; p < 0.001; I² = 88%; GRADE: very low), at 24 hours (MD = -0.56 cm; 95% CI = -1.14-0.01 cm; p = 0.05; I² = 97%; GRADE: very low).

CONCLUSIONS

Magnesium sulfate delayed TFAR and decreased 24-hour opioid consumption and early postoperative pain intensity. However, imprecision and inconsistency pervaded meta-analyses, causing very low certainty of effect estimates.

PRO AND CONTRA ON ADJUVANTS TO NEUROAXIAL ANESTHESIA AND PERIPHERAL NERVE BLOCKS

Modern approach in surgical treatment and in managing acute and chronic pain is nowadays more and more based on the implementation of all possible techniques of regional anesthesia (RA). Local anesthetics (LA) are needed to achieve standard regional anesthesia. Local anesthetics are primarily characterized by time constraints and duration of action, and depending on the amount applied, adverse effects on the cardiac and central nervous system may occur. Adjuvants are drugs used together with LA due to their synergistic effect, i.e. they improve start latency and duration of sensory and motor blockade and enable reduction of cumulative dose of LA and reduction of adverse effects on cardiac and nervous system. Nowadays, there is a huge variety of drugs that can be administered in combination with LA, and they, in general, can be divided into opioid and non-opioid adjuvants. The administration of opioids in RA over an extended time period was accompanied by some negative characteristics as respiratory depression, nausea, vomiting. So, their usage is still under a special control. Due to the positive effects shown by drugs from non-opioid adjuvants group (e.g. adrenaline, alpha adrenergic agonists, steroids, magnesium, midazolam, ketamine etc.), indications for their administration broadened. However, there are still some restrains in clinical practice based on the fact that neurotoxicity and demonstration of neurological complications in regional anesthesia haven't been properly researched yet.

NEW CONCEPT OF FUSION TECHNICS IN REGIONAL ANESTHESIA

The aim of this review article is to introduce a newer approach to multimodal anesthesia. In addition to the usual combination of epidural catheter and general anesthesia as standard techniques in surgical procedures accompanied by intense postoperative pain, we want to encourage reflection on the application of various regional techniques in equally complex surgical conditions. By simply modifying the standard neuraxial technique with a higher thoracic approach, excellent abdominal surgery can be performed to awake the patient. However, placement of an epidural catheter is not always possible due to technical difficulties or patient-related conditions that contraindicate its insertion. Trunk-level fascia blocks (PVB, ESPB, RLB) are simple, safe alternative to an epidural catheter because the transverse process, which is the target of ultrasound, is easily visualized and the injection site is away from neuroaxis, pleura, and large vascular structures. In addition, extensive craniocaudal diffusion of anesthetics allows wide coverage with a single injection. It has been confirmed that PVB, ESPB, RLB blocks act on visceral and somatic pain. Therefore, their ultrasound-guided use in laparoscopic and other abdominal surgeries may be useful. With a well-designed fusion of regional techniques in operations of the upper and lower abdomen, it is possible to achieve hemodynamically and respiratory stable anesthesia in an awake patient with reduced pos