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

Efficacy of Dexmedetomidine as an Adjuvant to Local Anesthetics in Peribulbar Block: A Meta-analysis With Trial-Sequential Analysis

PURPOSE

To assess the role of dexmedetomidine as an adjuvant to local anesthetics (LA) in enhancing the duration and quality of peribulbar blocks for ophthalmic surgeries.

DESIGN

Systematic review with meta-analysis and trial sequential analysis.

METHODS

We systematically searched MEDLINE, Embase, and Cochrane for randomized controlled trials involving adult patients undergoing ophthalmic surgery under peribulbar block, comparing LA alone vs LA + dexmedetomidine. Risk ratios (RR) and mean differences (MD) with 95% confidence intervals were computed using a random-effects model. Sensitivity and trial-sequential analyses were performed to assess inconsistencies and weight type I and II errors, and estimate the required information size of the samples for all end points.

RESULTS

Sixteen randomized controlled trials (1220 patients) were included. Compared with LA alone, dexmedetomidine was associated with prolonged (1) motor block duration (MD: 65.01 minutes, P < .001), (2) sensory block duration (MD: 81.94 minutes, P < .001), (3) reduced intraocular pressure (MD: -2.6 mm Hg, P < .001), and (4) decreased need for supplemental injections (RR: 0.44, P = .007). In addition, dexmedetomidine showed (5) longer time to analgesic request (MD: 97.15 minutes, P < .001) and (6) increased surgeon satisfaction (RR: 1.52, P = .01). Sensitivity analyses and trial-sequential analyses were consistent across all end points, and the required information size was achieved for most end points, indicating that pooled analyses were reliable and sample sizes were sufficient.

CONCLUSIONS

Compared with LA alone, dexmedetomidine significantly prolonged sensory and motor block duration and the time to the first analgesic request; moreover, it decreased intraocular pressure and the need for supplemental injections, while increasing surgeon satisfaction.

Gynecological Laparoscopic Surgeries under Spinal Anesthesia: Benefits and Challenges

OBJECTIVE

This prospective study investigated the feasibility of performing laparoscopic pelvic surgery under spinal anesthesia and analyzed the intraoperative side effects, like pain, nausea, and vomitus, of 915 patients.

METHODS

The implementation and performance of laparoscopic surgery under local anesthesia on 915 patients (out of a total of 3212 who underwent laparoscopic pelvic surgery under spinal anesthesia) were analyzed in relation to BMI (body mass index), obesity, pain during surgery, amount of intraperitoneal mmHg CO2 gas pressure, and surgical complications.

RESULTS

BMI > 30, intra-abdominal adhesions, increased duration of the operation, bleeding, and increased intraperitoneal CO2 pressure were statistically significant as the main causes of pain during laparoscopic surgery under spinal anesthesia. Underweight patients, on the other hand, had less pain when intra-abdominal pressure increased compared to those of normal weight. The appearance of pain, nausea, and vomitus occurred in 10.3% of patients, and these events were easy to manage and treat. They did not affect the surgeon's work or the course of the operation.

CONCLUSIONS

In light of these observations, we are proposing spinal anesthesia for laparoscopic surgery as the first choice in patients who have no contraindications. To the best of our knowledge, this clinical study constitutes the largest clinical observation and dataset concerning spinal anesthesia in laparoscopic pelvic surgery.

TRIAL REGISTRATION

ISRCTN38987, 10 December 2019.

Dexmedetomidine as an Adjuvant to Nerve Block for Cancer Surgery: A Systematic Review and Meta-Analysis

Background/Objectives: Our understanding of dexmedetomidine, as an adjuvant to nerve blocks in cancer surgery, is characterized by a current lack of compelling evidence, and it remains unknown whether the potential benefits of use outweigh the risks. The aim of the study was to evaluate the benefit and safety profiles of dexmedetomidine as an adjuvant to nerve blocks in cancer surgery. Methods: Systematic searches were conducted in MEDLINE, ScienceDirect, Cochrane Library, Springer, medRxiv, and Scopus up to 17 May 2024. Risk ratios (RR) for binary outcomes and standardized mean differences (SMDs) for continuous outcomes were quantified. Results: Twenty studies were identified. In breast cancer surgery, the use of dexmedetomidine reduced 24 h total morphine consumption (SMD = -1.99 [95% CI -3.01 to -0.98], p = 0.0001, I2 = 91%, random effects) and prolonged the requirement for morphine rescue analgesia (SMD = 2.98 [95% CI 0.01 to 5.95], p = 0.05, I2 = 98%, random effects). In abdominal cancer surgery, the dexmedetomidine group had lower total sufentanil consumption (SMD = -1.34 [95% CI -2.29 to -0.40], p = 0.005, I2 = 84%, random effects). Dexmedetomidine reduced the VAS score and decreased postoperative nausea and vomiting (PONV). No studies using dexmedetomidine reported serious adverse events. Conclusions: Using dexmedetomidine as an adjuvant to nerve blocks in cancer surgery could lower the VAS pain score and prolong the regional anesthesia duration, which would lead to a decrease in total opioid consumption and possibly contribute to fewer PONV events. Furthermore, the reports of no serious adverse events indicate its good safety profile.

The Effect of Dexmedetomidine as a Local Anesthetic Adjuvant for Iliac Fascia Compartment Block on Postoperative Delirium in Elderly Patients Undergoing Elective Hip Surgery

INTRODUCTION

We analyzed the effect of dexmedetomidine (DEX) as a local anesthetic adjuvant on postoperative delirium (POD) in elderly patients undergoing elective hip surgery.

METHODS

In this study, 120 patients undergoing hip surgery were enrolled and randomly assigned to two groups: fascia iliaca compartment block with DEX + ropivacaine (the Y group, n = 60) and fascia iliaca compartment block with ropivacaine (the R group, n = 60). The primary outcomes: presence of delirium during the postanesthesia care unit (PACU) period and on the first day (D1), the second day (D2), and the third day (D3) after surgery. The secondary outcomes: preoperative and postoperative C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), occurrence of insomnia on the preoperative day, day of operation, D1 and D2; HR values of patients in both groups before iliac fascia block (T1), 30 min after iliac fascia block (T2), at surgical incision (T3), 20 min after incision (T4), when they were transferred out of the operating room (T5) and after leaving the recovery room (T6) at each time point; VAS for T1, PACU, D1, D2; the number of patients requiring remedial analgesics within 24 h after blockade and related complications between the two groups.

RESULTS

A total of 97 patients were included in the final analysis, with 11 and 12 patients withdrawing from the R and Y groups, respectively. The overall incidence of POD and its incidence in the PACU and ward were all lesser in the Y group than in the R group (p < 0.05). Additionally, fewer cases required remedial analgesia during the PACU period, and more vasoactive drugs were used for maintaining circulatory system stability in the Y group as compared to the R group (p < 0.05). At the same time, the incidence of intraoperative and postoperative bradycardia in the Y group was higher than that in the R group, accompanied by lower postoperative CRP and ESR (all p < 0.05).

CONCLUSION

Ultrasound-guided high fascia iliaca compartment block with a combination of ropivacaine and DEX can reduce the incidence of POD, the use of intraoperative opioids and postoperative remedial analgesics, and postoperative inflammation in elderly patients who have undergone hip surgery, indicating that this method could be beneficial in the prevention and treatment of POD.

Regional versus systemic dexmedetomidine as an adjuvant to lidocaine for intravenous regional anaesthesia in healthy volunteers: a randomized crossover study

BACKGROUND

Dexmedetomidine enhances the quality and duration of lidocaine intravenous regional anaesthesia (IVRA). However, the two administration routes have not been directly compared regarding effects on tourniquet tolerance time with lidocaine IVRA. Additionally, it remains unclear whether the prolonged tourniquet tolerance stems from the direct peripheral action of dexmedetomidine or indirect systemic analgesic effects.

METHODS

We conducted forearm IVRA in 12 healthy volunteers using a crossover design on two separate study days. One day, the systemic dexmedetomidine group received an intravenous infusion of 0.5 μg/kg dexmedetomidine (20 mL) in one arm, followed by 0.5% lidocaine (25 mL) forearm IVRA in the contralateral arm. On the other day, the regional dexmedetomidine group received an intravenous 0.9% saline infusion (20 mL) in one arm, followed by combined 0.5% lidocaine (25 mL) and 0.5 μg/kg dexmedetomidine forearm IVRA in the opposite arm. After a two-week washout period, participants crossed over to receive the alternate treatment. The primary outcome was tourniquet tolerance time, from initiating IVRA until the patient-reported tourniquet pain numerical rating scale exceeded three.

RESULTS

The tourniquet tolerance time was longer with regional versus systemic dexmedetomidine (36.9 ± 7.6 min vs 23.3 ± 6.2 min, respectively), with a 13.6 min mean difference (95% CI: 10.8 to 16.4 min, p < 0.001). Regional dexmedetomidine also hastened sensory onset and extended sensory recovery compared to systemic administration. Delayed sedation after tourniquet release occurred in 5 of 12 subjects receiving regional dexmedetomidine.

CONCLUSION

The addition of regional dexmedetomidine to lidocaine prolonged tourniquet tolerance time in forearm IVRA to a greater extent compared to systemic dexmedetomidine in healthy volunteers.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2300067978.

Efficacy of Pre-emptive Infiltration of Dexmedetomidine with a Local Anaesthetic on Postoperative Pain in Maxillofacial Trauma Management under General Anaesthesia: A Prospective Study

Introduction

Pre-emptive analgesia aims to reduce post-operative pain and the need for analgesics. Dexmedetomidine (DEX) is an alpha-2 adrenergic agonist with sedative and analgesic properties. The aim of this study was to compare the effectiveness of pre-emptive infiltration of DEX combined with local anaesthetic (2% lignocaine with adrenaline) in managing post-operative pain in maxillofacial trauma patients undergoing open reduction and internal fixation procedures, as compared to pre-emptive infiltration of placebo (saline) with the same local anaesthetic.

Materials and Methods

Forty-two participants of maxillofacial trauma with a Visual Analogue Scale (VAS) score of more than 4 were included in this double-blinded randomised controlled trial. Group DL (Dexmedetomidine with local anaesthetic) received dexmedetomidine (DEX) with local anaesthesia while group PL (placebo with local anaesthetic) received placebo with local anaesthesia. Participants were evaluated for the time taken for the first rescue analgesic, total doses of fentanyl taken by the patient in the first 24 h, post-operative pain (VAS) at 6, 12, 16 and 24 h, post-operative side effects and analysed.

Results

The DL group had a significantly longer time to first rescue analgesic compared to the PL group. Surgeons in the DL group reported higher satisfaction and better surgical field visibility. Post-operative VAS scores were lower in the DL group at 6 and 12 h, with a median score of 1 at 16 and 24 h.

Discussion

Pre-emptive DEX infiltration is effective in reducing post-operative pain and opioid consumption in maxillofacial trauma cases undergoing open reduction and internal fixation. This approach can enhance patient comfort and improve surgical outcomes without significant risks.

Advances in Anesthesia for Shoulder Surgery: A Comprehensive Review of Dexmedetomidine-Enhanced Interscalene Brachial Plexus Block

Surgical procedures on the shoulder pose distinctive challenges in managing pain during the perioperative period, underscoring the importance of exploring innovative anesthesia techniques. This comprehensive review article delves into integrating dexmedetomidine, an alpha-2 adrenergic agonist, within interscalene brachial plexus blocks for shoulder surgery. The review initiates by underscoring the pivotal role of effective anesthesia in shoulder surgery and elucidates the rationale behind investigating dexmedetomidine as an adjunct. It meticulously examines the anatomy and physiology of the brachial plexus, emphasizing its critical significance in shoulder surgery. Furthermore, the article expounds on dexmedetomidine's mechanisms of action and pharmacokinetics, encompassing its safety profile and potential side effects. The conventional interscalene brachial plexus block techniques, along with their limitations and challenges, are discussed, laying the foundation for the integration of dexmedetomidine. The review subsequently delves into exploring the role of dexmedetomidine in regional anesthesia, covering previous studies, mechanisms of action, and the potential advantages of incorporating it into nerve blocks. The review's core concentrates on the practical application of dexmedetomidine-enhanced interscalene brachial plexus blocks. This includes discussions on administration techniques, dosage guidelines, and compelling evidence supporting its utilization. Clinical scenarios where this approach proves most advantageous are thoroughly explored, comparing its effectiveness with traditional techniques in terms of pain control and patient outcomes. A comprehensive examination of relevant clinical trials and case studies highlights the evidence supporting its efficacy. The review also underscores safety considerations associated with dexmedetomidine. It proposes strategies for mitigating risks to ensure patient safety. Insights into future directions and research are provided, encompassing ongoing studies, areas necessitating further investigation, and potential refinements in technique. Finally, the article summarizes key findings, emphasizing the practicality of dexmedetomidine-enhanced interscalene brachial plexus blocks in shoulder surgery and its far-reaching implications for clinical practice and patient care.

Effect of Different Administration Routes of Dexmedetomidine on Postoperative Delirium in Elderly Patients Undergoing Elective Spinal Surgery: A Prospective Randomized Double-Blinded Controlled Trial

BACKGROUND

Intravenous dexmedetomidine has been reported to decrease the occurrence of postoperative delirium (POD) in elderly patients. Nevertheless, some previous studies have indicated that intratracheal dexmedetomidine and intranasal dexmedetomidine are also effective and convenient. The current study aimed to compare the effect of different administration routes of dexmedetomidine on POD in elderly patients.

METHODS

We randomly allocated 150 patients (aged 60 years or more) scheduled for spinal surgery to receive intravenous dexmedetomidine (0.6 μg/kg), intranasal dexmedetomidine (1 μg/kg) before anesthesia induction, or intratracheal dexmedetomidine (0.6 µg/kg) after anesthesia induction. The primary outcome was the frequency of delirium during the first 3 postoperative days. The secondary outcomes were the incidence of postoperative sore throat (POST) and sleep quality. Adverse events were recorded, and routine treatment was performed.

RESULTS

Compared with the intranasal group, the intravenous group had a significantly lower occurrence of POD within 3 days (3 of 49 [6.1%] vs 14 of 50 [28.0%]; odds ratio [OR], 0.17; 95% confidence intervals [CIs], 0.05-0.63; P < .017). Meanwhile, patients in the intratracheal group had a lower incidence of POD than those in the intranasal group (5 of 49 [10.2%] vs 14 of 50 [28.0%]; OR, 0.29; 95% CI, 0.10-0.89; P < .017). Whereas, there was no difference between the intratracheal and intravenous groups (5 of 49 [10.2%] vs 3 of 49 [6.1%]; OR, 1.74; 95% CI, 0.40-7.73; P > .017). The rate of POST was lower in the intratracheal group than that in the other 2 groups at 2 hours after surgery (7 of 49 [14.3%] vs 12 of 49 [24.5%] vs 18 of 50 [36.0%], P < .017, respectively). Intravenous dexmedetomidine had the lowest Pittsburgh Sleep Quality Index score on the second morning after surgery (median [interquartile range {IQR}]: 4 [3-5] vs 6 [4-7] vs 6 [4-7], P < .017, respectively). Compared with the intranasal group, the intravenous group had a higher rate of bradycardia and a lower incidence of postoperative nausea and vomiting ( P < .017). The intranasal group was associated with the highest incidence of hypertension ( P < .017).

CONCLUSIONS

For patients aged ≥60 years undergoing spinal surgery, compared with the intranasal route of dexmedetomidine, intravenous and intratracheal dexmedetomidine reduced the incidence of early POD. Meanwhile, intravenous dexmedetomidine was associated with better sleep quality after surgery, and intratracheal dexmedetomidine resulted in a lower incidence of POST. Adverse events were mild in all 3 administration routes of dexmedetomidine.

Effect of Dexmedetomidine Added to Lidocaine Cartridge on the Level of Patient Sedation, Cooperation, and Patient and Surgeon Satisfaction during Mandibular Third-Molar Extraction Surgery: A Randomized Double-Blind Controlled Trial

Background. Various methods have been introduced for anxiety control during third-molar extraction surgery. Dexmedetomidine (DEX) is known to have analgesic, anxiolytic, and sympatholytic properties with minimal adverse effects. This study aimed to evaluate the impact of the local injection of the combination of DEX and Lidocaine on patients’ anxiety and the surgeon’s satisfaction during third-molar extraction surgery. Methods. A total number of 26 healthy volunteers with symmetrical bilateral impacted mandibular third-molar teeth indicated for surgical removal were included in this double-blind randomized controlled trial. A single experienced surgeon performed two surgical extraction procedures within at least four-week time intervals using anesthetic cartridges containing “DEX + LIDO” or “LIDO alone” used randomly on each side for each patient. The Visual Analog Scale and the SDFQ index were used to evaluate patients’ anxiety and surgeon satisfaction during the procedure. Results. SDFQ reports showed that patients in the “DEX” group were 1.5 times more relaxed than those in the “LIDO alone” group. As a result, the level of sedation was considered statistically significant between the two groups (Wilcoxon test, $P$ value <0.019). Wilcoxon test results also showed significant differences between the two groups regarding patients’ overall cooperation in terms of interfering movement and verbal presentation of discomfort ( $P$ value <0.05); however, this difference was not considered significant regarding nonverbal signs of discomfort ( $P$ value >0.05). Moreover, both the surgeon and the patients reported a significantly higher satisfaction rate in the DEX group (paired T-test, df = 25, $P$ value <0.05). Conclusions. It was inferred from the outcomes of the present study that the application of DEX added to the LIDO local anesthesia cartridge could significantly benefit anxious patients with previous unpleasant dental treatment experiences. Trial Registration. This trial is registered with the clinical trial registration number: IRCT20200406046966N.