Efficacy of perineural versus intravenous dexmedetomidine as a peripheral nerve block adjunct: a systematic review

Intravenous versus perineural dexamethasone to prolong analgesia after interscalene brachial plexus block: a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

The efficacy of perineural vs intravenous dexamethasone as a local anaesthetic adjunct to increase duration of analgesia could be particular to specific peripheral nerve blocks because of differences in systemic absorption depending on the injection site. Given this uncertainty, we performed a systematic review with meta-analysis and trial sequential analysis comparing dexamethasone administered perineurally or intravenously combined with local anaesthetic for interscalene brachial plexus block.

METHODS

Following a search of various electronic databases, we included 11 trials (1145 patients). The primary outcome was the duration of analgesia defined as the time between peripheral nerve block or onset of sensory blockade and the time to first analgesic request or initial report of pain.

RESULTS

The primary outcome, duration of analgesia, was greater in the perineural dexamethasone group, with a mean difference (95% confidence interval) of 122 (62-183) min, I2=73%, P<0.0001. Trial sequential analysis indicated that firm evidence had been reached. The quality of evidence was downgraded to low, mainly because of moderate inconsistency and serious publication bias. No significant differences were present for any of the secondary outcomes, except for onset time of sensory and motor blockade and resting pain score at 12 h, but the magnitude of differences was not clinically relevant.

CONCLUSIONS

There is low-quality evidence that perineural administration of dexamethasone as a local anaesthetic adjunct increases duration of analgesia by an average of 2 h compared with intravenous injection for interscalene brachial plexus block. Given the limited clinical relevance of this difference, the off-label use of perineural administration, and the risk of drug crystallisation, we recommend intravenous dexamethasone administration.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023466147).

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

In this chapter, we review how ligands, both agonists and antagonists, for the major classes of adrenoreceptors, are utilized in acute care clinical settings. Adrenergic ligands exert their effects by interacting with the three major classes of adrenoceptors. Adrenoceptor agonists and antagonists have important applications, ranging from treatment of hypotension to asthma, and have proven to be extremely useful in a variety of clinical settings of acute care from the operating room to the critical care environment. Continued research interpreting the mechanisms of adrenoreceptors may help the discovery of new drugs with more desirable clinical profiles.

Regional anaesthesia for ambulatory surgery

Regional anaesthesia (RA) has an important and ever-expanding role in ambulatory surgery. Specific practices vary depending on the preferences and resources of the anaesthesia team and hospital setting. It is used for various purposes, including as primary anaesthetic technique for surgery but also as postoperative analgesic modality. The limited duration of action of currently available local anaesthetics limits their application in postoperative pain control and enhanced recovery. The search for the holy grail of regional anaesthetics continues. Current evidence suggests that a peripheral nerve block performed with long-acting local anaesthetics in combination with intravenous or perineural dexamethasone gives the longest and most optimal sensory block. In this review, we outline some possible blocks for ambulatory surgery and additives to perform RA. Moreover, we give an update on local anaesthesia drugs and adjuvants, paediatric RA in ambulatory care and discuss the impact of RA by COVID-19.

Perineural dexmedetomidine in femoral nerve blocks increases the duration of postoperative analgesia for anterolateral thigh flap donor sites in patients with oral cancer

Although the duration of analgesia provided by a single-shot nerve block is limited, perineural dexmedetomidine significantly enhances nerve blocks during extremity surgery. This study aimed to investigate the role of dexmedetomidine added to ropivacaine in femoral nerve blocks for postoperative analgesia of the anterolateral thigh (ALT) flap donor site in patients with oral cancer. Fifty-two participants scheduled for maxillofacial tumor resection and reconstruction using an anterolateral thigh flap were randomly allocated to either the Ropi group (femoral nerve block with ropivacaine) or the Ropi + Dex group (femoral nerve block with ropivacaine plus dexmedetomidine). The primary outcome was the duration of the sensory block, while the secondary outcomes were 24 h postoperative sufentanil use, number of patients using rescue analgesics, vital signs, postoperative pain score, incidence of agitation, and presence of adverse effects. Dexmedetomidine plus ropivacaine significantly prolonged the duration of sensory block compared with ropivacaine alone (10.4 ± 0.9 h vs 14.0 ± 1.3 h; P < 0.001). Age was positively correlated with increased duration of sensory block (r = 0.300; P = 0.033). Postoperative pain scores at the donor sites were lower in the Ropi + Dex group than in the Ropi group, at 12 h after surgery (P < 0.001). Although there were no statistically significant differences in the incidence of bradycardia between the two groups, four patients treated with dexmedetomidine experienced episodes of bradycardia. Perineural dexmedetomidine prolonged the duration of femoral nerve block and reduced postoperative pain scores at the ALT flap donor sites in patients with oral cancer.

Evaluation of the effects of bupivacaine combined with sugammadex on the duration of the nociceptive blockade in sciatic nerve blocks: a controlled, double-blind animal study

BACKGROUND

Animal and other experimental studies have demonstrated increased block time and quality when α- and β-cyclodextrin drugs are combined with local anesthetics. However, to our knowledge, no study has utilized γ-cyclodextrins in such a combination. In the present study, we used an animal model to evaluate the effects of different doses of the combined administration of γ-cyclodextrin (sugammadex) and bupivacaine on the duration of sciatic nerve blocks in rats.

METHODS

Sciatic nerve blocks were performed with a 0.20 ml mixture in all groups. For the non-experimental groups, this mixture consisted of 0.2 ml saline (Sham group), 0.2 ml sugammadex (Group S), or 0.16 ml bupivacaine 0.5% and 0.04 ml saline (Group B). For the experimental groups, 0.16 ml bupivacaine 0.5% was administered along with 0.01 ml sugammadex and 0.03 ml saline (Group BS1), 0.02 ml sugammadex and 0.02 ml saline (Group BS2), or 0.04 ml sugammadex (Group BS4). Proprioception, nociception, and motor function were evaluated until the sciatic block was completely reversed.

RESULTS

Motor, proprioceptive, and nociceptive blockades occurred within 5 min in all experimental groups. In Group BS4, the duration of the motor, proprioceptive, and nociceptive blockades was significantly increased compared with the other experimental groups. However, in Groups BS1 and BS2, only the duration of the nociceptive blockade was significantly increased.

CONCLUSIONS

The combined administration of sugammadex and bupivacaine for sciatic nerve blocks in rats led to a significant increase in the duration of motor, proprioceptive, and nociceptive blockades.

Evaluation of a constant rate intravenous infusion of dexmedetomidine on the duration of a femoral and sciatic nerve block using lidocaine in dogs

Objectives

This study investigated the effects of 1 μg/kg/h intravenous constant rate infusion (CRI) of dexmedetomidine on the sensory and motor blockade for femoral and sciatic nerve blocks in dogs undergoing stifle surgery.

Materials and methods

Client-owned dogs referred for stifle surgery were enrolled in this prospective, randomized, blinded study. Dogs were pre-medicated with acepromazine (0.005-0.01 mg/kg intramuscularly, IM); anesthesia was induced with propofol intravenously and maintained with isoflurane in a mixture of air and oxygen. Electrolocation-guided sciatic and femoral nerve blocks with lidocaine 2% (0.15 mL/kg) were performed using the parasacral and lateral pre-iliac approaches, respectively. After performing local block, a systemic infusion of saline solution (group C) or dexmedetomidine (group D) was started at a CRI at 1 ml/kg/h and continued until the end of surgery. Dexmedetomidine was infused at a dose of 1 μg/kg/h. Respiratory and hemodynamic variables were recorded during surgery. Sensory and motor blockade was evaluated by response to pinching the skin innervated by the sciatic/femoral nerves, with forceps and by observing the dogs' ability to walk and testing proprioception at 30, 60, 120, 180, and 240 min after extubation. Analgesia was monitored with SF-GCPS. Methadone IM was administered as rescue analgesia. Intraoperative data were analyzed by analysis of variance, while postoperative data were analyzed by the independent two-tailed t-test and a Kaplan-Meier test (p < 0.05).

Results

Twenty dogs were included in this study (10/group). A significant difference in the recovery of sensory nerve function was observed between the groups. The mean durations of the sensory blockade for femoral and sciatic nerves, respectively, was longer (p < 0.001) for group D [168 (146-191, 95% CI), 161 (143-179, 95% CI) min] than in group C [120 (96.1-144, 95% CI), 116 (90.9-142, 95% CI]. No differences in the recovery of patellar and tibial reflexes, proprioceptive function, and ability to walk were found among groups. The overall postoperative rescue analgesia requirement was significantly different (p = 0.019) between groups, with an incidence of 5/10 (50%) dogs in group D and 10/10 (100%) dogs in group C.

Conclusion

Dexmedetomidine administered as a CRI (1 μg/kg/h) combined with local lidocaine increases the duration of the sensory component of the sciatic and femoral nerve blocks and reduces the requirement for additional analgesia during the immediate postoperative hours.

Techniques and complications of popliteal nerve blocks

BACKGROUND

Use of popliteal nerve blocks (PNBs) as an alternative or adjunctive therapy to traditional methods of pain control (e.g., systemic or spinal anesthesia and opioids) is increasingly popular in foot and ankle surgery.

METHODS

We reviewed online databases for literature on PNBs in foot and ankle surgery to analyze the various techniques and positioning used, the influence of drugs on their efficacy, and possible complications associated with their use. Thirty articles were identified with a predefined search criteria, followed by a review process for relevance.

RESULTS

Patient demographics, procedure specifics, and block techniques, such as anesthetic used, can impact the duration and success of a PNB. Administration with ultrasound guidance proved superior to nerve stimulation, and preoperative administration was superior to postoperative administration.

CONCLUSIONS

PNBs are an effective method to control postoperative pain with minimal complications, leading to decreased analgesic use, earlier discharge, and higher patient satisfaction.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Low-dose dexmedetomidine as a perineural adjuvant for postoperative analgesia: a randomized controlled trial

Purpose

Dexmedetomidine has been proposed as an additive to local anesthetics to prolong peripheral nerve block duration; however, perineural dexmedetomidine has been associated with an increased risk of bradycardia and hypotension This randomized controlled study investigated the effects of low-dose dexmedetomidine as a perineural adjuvant for postoperative analgesia.

Methods

Fifty-five patients who had undergone elective upper extremity surgery were randomized to receive an ultrasound-guided supraclavicular brachial plexus block with 20 mL 0.5% ropivacaine with or without 30 μg dexmedetomidine. The primary outcome was the duration of analgesia. Secondary outcomes included the onset time and duration of the motor and sensory blocks, incidence of hypotension and bradycardia, total postoperative analgesics, and safety assessment during the 24 h after surgery.

Results

Dexmedetomidine significantly prolonged the duration of analgesia (887 ± 92 min vs 661 ± 83 min, P < 0.0001). The onset time and the duration of motor and sensory block were significantly different between the groups (all P < 0.001). No episodes of hypotension or bradycardia were detected in the dexmedetomidine group. The total postoperative analgesic use and side effect profiles in the first 24 h postoperative period were similar for both groups.

Conclusions

Low-dose dexmedetomidine (30 μg) as a perineural adjuvant significantly prolonged the analgesic duration of a brachial plexus block without inducing hemodynamic instability.

Trial registration

This trial was registered at ClinicalTrial.gov (NCT02630290).

Comparing Effect of Adding Ketamine versus Dexmedetomidine to Bupivacaine in Pecs-ⅠⅠ Block on Postoperative Pain Control in Patients Undergoing Breast Surgery

BACKGROUND

Pecs-II block has previously and successfully demonstrated a good quality of perioperative analgesia for breast surgery.

OBJECTIVE

This study aimed to compare the quality of postoperative pain control when adding either ketamine or dexmedetomidine to bupivacaine 0.25% for Pecs-II block.

METHODS

This prospective randomized double-blind study was conducted on 159 female patients with American society of anesthesiologist (ASA) physical status class I-III scheduled to have modified radical mastectomy. Patients were randomly assigned into three groups. Each group included 53patients to receive ultrasound guided Pecs-II blocks with either 32 mL of 0.25% bupivacaine added to ketamine hydrochloride 1 mg/kg (BK group), 32 mL of 0.25%bupivacaine added to dexmedetomidine 1 ug/kg (BD group) or 32 mL of 0.25% bupivacaine only (B group).The primary outcome of this study was the total postoperative morphine consumption for the first 24 hours postoperatively. The time of the first request of analgesia, the pain scores at rest of ipsilateral arm, and the intra-operative fentanyl requirements, were the secondary outcome measures. Any side effects occurred were recorded.

RESULTS

The total postoperative morphine consumption was significantly lower in patients received bupivacaine with addition of either ketamine (BK group), (10.3±2.6 mg), or dexmedetomidine (BD group), (3.8±0.2 mg) respectively, versus patients received only bupivacaine (B group), (16.9±5.3 mg). Both ketamine (BK group) and dexmedetomidine (BD group) added to bupivacaine significantly prolonged the time to first analgesic request (16.7±4.5 h), (21.6±1.6 h) in both groups respectively compared to patients received bupivacaine alone (B group), (11.5±1.2 h).The pain score was variable between the three groups over different times during the first 24 hours postoperatively. There was no significant difference in perioperative hemodynamics, O2 saturation, sedation scores or side effects observed between the three groups. Patient satisfaction was reported to be the best in patients received dexmedetomidine added to bupivacaine than the other patients who received ketamine as an additive or those who received bupivacaine alone.

CONCLUSION

Adding dexmedetomidine to bupivacaine provides more effective postoperative pain control than adding ketamine during Pecs-II blocks for breast cancer surgery.

Dexmedetomidine prolongs the duration of local anesthetics when used as an adjuvant through both perineural and systemic mechanisms: a prospective randomized double-blinded trial

Background

To study the respective peripheral and systemic mechanisms of action of dexmedetomidine, as adjuvant to regional anesthesia, we compared dexmedetomidine added to ropivacaine for mid-forearm nerve blocks, to either systemic-only dexmedetomidine, and to a control with no dexmedetomidine.

Methods

Sixty patients undergoing hand surgery were randomly divided into three groups (n = 20 per group). Each group underwent a triple-nerve (median, radial and ulnar) mid-forearm blocks with 0.75% ropivacaine. In the DexP group, 60 µg of dexmedetomidine were added to the anesthetic mixture, while in the DexIV group, they were intravenously infused. Normal saline as a placebo was used, either as adjuvant, or intravenously. All patients underwent also a supraclavicular block with 1.5% lidocaine for tourniquet pain. The main outcomes were the duration of analgesia and the duration of sensory blockade separately for each nerve termination of the upper limb, and the duration of motor blockade of the upper limb. Tolerance was assessed by blood pressure and heart rate, and the report of adverse events.

Results

Duration of analgesia was longer in the DexP group, in comparison to the two other groups (P < 0.001), while it was similar in the DexIV and the control group. For cutaneous territories targeted by the three mid-forearm blocks, the between-group differences behaved similarly. For the other cutaneous territories (musculocutaneous and posterior brachial cutaneous nerves), duration of sensory blockade was shorter in the control group than in the two dexmedetomidine groups. For duration of motor blockade, the between-group differences behaved similarly. Both blood pressure and heart rate were reduced in the DexP and the DexIV groups, compared to the control.

Conclusions

Dexmedetomidine used as an adjuvant to regional anesthesia may act mostly though a perineural mechanism, especially for the sensory aspects of anesthesia. A systemic action might however explain other clinical effects.

Trial registration

ChiCTR-IOR-17011149, date of registration: 16/04/2017

The Use of Multimodal Perineural Adjuvants in Pediatric Peripheral Nerve Blocks: Technique and Experiences

Background

Postoperative pain management in pediatric population can be very challenging. How to prolong the duration of single-injection peripheral nerve blocks has been widely discussed. Multiple medications are under investigation to accomplish this, yet data specifically focused on their use in pediatric peripheral nerve blocks are limited.

Methods

Anesthetic electronic medical records were queried for any instances where adjuvant drug(s) were used in peripheral nerve blocks during a two-year period at a pediatric surgical specialty hospital. These included buprenorphine, clonidine, dexamethasone, and dexmedetomidine. 

Results

Out of 1,845 blocks placed during the study period, 1,148 (62.2%) utilized perineural adjuvants. Buprenorphine as a sole agent was the most common choice (49.5%), followed by buprenorphine and dexmedetomidine combined (39.9%), dexmedetomidine alone (10.1%), and the rare combination of all three drugs, buprenorphine, dexmedetomidine, and dexamethasone (0.5%). The mean dose of buprenorphine given was 3.6 mcg/kg total, 2.8 mcg/kg/block. The mean dose of dexmedetomidine given was 0.9 mcg/kg total, 0.6 mcg/kg/block. The mean dose of dexamethasone utilized was 2 mg total, 1 mg/block. 

Conclusions

This report examined one institution’s use of multimodal perineural adjuvants in over 1,000 pediatric peripheral nerve blocks. Buprenorphine was the agent most commonly used to prolong the single-injection peripheral nerve block. This highlights the need for future prospective trials evaluating efficacy and safety.

Efficacy of dexmedetomidine as an adjuvant in femoral nerve block for post-op pain relief in hip surgery: A prospective randomized double-blind controlled study

Background and Aims:

To determine whether the addition of dexmedetomidine either in peripheral block or via systemic route leads to prolongation of the duration of analgesia is inconclusive. The present study aimed to assess the duration of postoperative analgesia with dexmedetomidine used as an additive with bupivacaine for ultrasound-guided femoral nerve block (FNB) and to compare it with intramuscular dexmedetomidine along with FNB.

Material and Methods:

A prospective, double-blind randomized clinical trial involving adult patients undergoing elective hip surgery, performed under subarachnoid block. When sensory block receded to T12 after the surgery, FNB was given for postoperative analgesia. Patients were randomized into three groups; Group A received FNB with 40 mL 0.25% bupivacaine and 0.5 mL saline as IM injection, Group B received FNB with 39.5 mL of 0.25% bupivacaine + 0.5 mL (50 mcg) of dexmedetomidine in the affected limb and 0.5 mL saline IM injection, and Group C received FNB with 40 mL of 0.25% bupivacaine and 0.5 mL (50 mcg) of dexmedetomidine as IM injection. Postoperative pain was assessed and for pain with VAS score >3, intravenous tramadol was given as rescue analgesia. Chi-square test for categorical variables and one-way ANOVA for continuous variables.

Results:

The mean duration of analgesia in groups A, B, and C was 671, 676, and 490 min, respectively which was not significant. A 24 h analgesic requirement was also not different between the groups.

Conclusion:

The use of dexmedetomidine perineurally or systemically did not prolong the duration of analgesia as compared to bupivacaine alone for femoral nerve block.