Dexmedetomidine as an Adjuvant in Peripheral Nerve Block

Bilateral ultrasound-guided erector spinae plane block for postoperative analgesia in paediatric idiopathic scoliosis patients undergoing posterior spine fusion surgery: a randomized controlled trial

PURPOSE

Major spinal surgery causes severe pain. We examined the ability of erector spinae plane block (ESPB) to alleviate pain after posterior spinal fusion (PSF) in paediatric scoliosis patients.

METHODS

Seventy-two patients who underwent PSF were randomized into a preoperative ultrasound-guided ESPB group or a no-block control group. The composite primary outcome was the area under the curve (AUC) of the numerical rating scale (NRS) score in the first 24 h after surgery and the number of parent-controlled intravenous analgesia (PCIA) boluses administered 24 h after surgery. The secondary outcomes included the NRS score, opioid consumption, rescue analgesia, adverse events, and quality of recovery.

RESULTS

The AUC-NRS at rest was 62 (13) in the ESPB group and 89 (13) in the control group (P < 0.001). There were 15 (5) 24-h PCIA boluses administered in the ESPB group and 30 (7) in the control group (P < 0.001). Compared with those in the control group, the NRS scores at rest were lower in the ESPB group at 0, 3, 6, and 9 h postoperatively, and the NRS scores during movement were lower in the ESPB group at 0, 3, 6, 9 and 12 h postoperatively. The ESPB group showed a lower need for PCIA than did the control group at 0-6, 6-12, 12-18 and 1-24 h postoperatively. In the ESPB group, fewer patients required rescue analgesics, and patients exhibited a higher quality of recovery.

CONCLUSION

Preoperative ESPB improves postoperative analgesia in paediatric scoliosis patients who underwent PSF.

TRIAL REGISTRATION NUMBER

ChiCTR2300074505.

DATE OF REGISTRATION

August 8, 2023.

Effects of Dexmedetomidine Added to Ropivacaine in Ultrasound-Guided Continuous Pericapsular Nerve Group Block Among Elderly Patients Undergoing Total Hip Arthroplasty

Total hip arthroplasty (THA) is a highly effective intervention for addressing hip joint issues, yet managing perioperative pain remains a significant challenge. In this study, we aimed to investigate the impact of supplementing ropivacaine with dexmedetomidine in ultrasound-guided continuous pericapsular nerve group block (PENGB) among elderly patients undergoing THA. We conducted a retrospective analysis involving 112 elderly patients who underwent THA. These patients were divided into two groups: the Control group, receiving ropivacaine alone, and the DEX group, receiving ropivacaine combined with dexmedetomidine. We evaluated various parameters including hemodynamic data, postoperative pain levels assessed using the Visual Analog Scale, cognitive status measured with the Montreal Cognitive Assessment, and serum markers (S100β and GFAP). Our findings revealed that the DEX group exhibited improved stability in blood pressure and oxygen saturation following surgery. Moreover, patients in the DEX group reported significantly lower levels of pain at 6 and 12 hours postsurgery, with a prolonged duration of pain relief. Furthermore, dexmedetomidine administration was associated with preserved cognitive function during the early postoperative period. Analysis of serum markers suggested potential cognitive protection conferred by the addition of dexmedetomidine. Overall, our study underscores the multifaceted benefits of incorporating dexmedetomidine into ropivacaine-based PENGB for elderly THA patients.

Mapping Theme Trends and Research Frontiers in Dexmedetomidine Over Past Decade: A Bibliometric Analysis

Background

Dexmedetomidine, an α2-adrenergic receptor (α2-AR) agonist, is extensively used in clinical and animal studies owing to its sedative, analgesic, and anxiolytic effects. The diverse range of research domains associated with dexmedetomidine poses challenges in defining pivotal research directions. Therefore, this study aimed to conduct a qualitative and quantitative bibliometric study in the field of dexmedetomidine over the past decade to establish current research trends and emerging frontiers.

Methods

Relevant publications in the field of dexmedetomidine between 2014 and 2023 were extracted from the Web of Science Core Collection database. The bibliometric analysis, incorporating statistical and visual analyses, was conducted using CiteSpace (6.1.R6) and R (4.3.1).

Results

The present study encompassed a total of 5,482 publications, exhibiting a consistent upward trend over the past decade. The United States and its institutions had the highest centrality. Ji, Fuhai, and Ebert, Thomas J. were identified as the most productive author and the most cited author, respectively. As anticipated, the most cited journal was Anesthesiology. Moreover, cluster analysis of cited references and co-occurrence of keywords revealed that recent studies were primarily focused on sedation, delirium, and opioid-free anesthesia. Finally, a timeline view of keywords clusters and keywords burst demonstrated that primary research frontiers were stress response, neuroinflammation, delirium, opioid-free anesthesia, peripheral nerve block, and complications.

Conclusion

Current research trends and directions are focused on sedation, delirium, and opioid-free anesthesia, as evidenced by our results. The frontier of future research is anticipated to encompass basic investigations into dexmedetomidine, including stress response and neuroinflammation, as well as clinical studies focusing on delirium, opioid-free anesthesia, peripheral nerve block, and associated complications.

Effects of Ultrasound-Guided Thoracic Paravertebral Nerve Block Combined with Perineural or IV Dexmedetomidine on Acute and Chronic Pain After Thoracoscopic Resection of Lung Lesions: A Double-Blind Randomized Trial

Background

Thoracic paravertebral block (TPVB) analgesia can be prolonged by local anesthetic adjuvants such as dexmedetomidine. This study aimed to evaluate the two administration routes of dexmedetomidine on acute pain and chronic neuropathic pain (NeuP) prevention compared with no dexmedetomidine.

Methods

A total of 216 patients were randomized to receive TPVB using 0.4% ropivacaine alone (R Group), with perineural dexmedetomidine 0.5 μg·kg-1 (RD0.5 Group) or 1.0 μg·kg-1 (RD1.0 Group), or intravenous (IV) dexmedetomidine 0.5 μg·kg-1·h-1 (RDiv Group). The primary outcome was the incidence of chronic NeuP, defined as a Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain score > 12 points at 3-month after surgery.

Results

(1) For the primary outcome, RD0.5 Group and RD1.0 Group demonstrated a decreased incidence of chronic NeuP at 3-month after surgery; (2) Compared with R Group, RDiv Group, RD0.5 Group, and RD1.0 Group can reduce VAS scores at rest and movement and Prince-Henry Pain scores at 12 and 24-h after surgery, the consumption of oral morphine equivalent (OME) and improve QOD-15 at POD1; (3) Compared with RDiv Group, RD0.5 Group and RD1.0 Group can reduce VAS scores at rest and movement and Prince-Henry Pain scores at 12 and 24-h after surgery, the consumption of postoperative OME and improve QOD-15 at POD1; (4) Compared with RD0.5 Group, RD1.0 Group effectively reduced VAS scores at rest at 12 and 24-h after surgery, VAS scores in movement and Prince-Henry Pain scores at 12-h after surgery. However, RD1.0 Group showed an increased incidence of drowsiness.

Conclusion

Perineural or IV dexmedetomidine are similarly effective in reducing acute pain, but only perineural dexmedetomidine reduced chronic NeuP. Moreover, considering postoperative complications such as drowsiness, perineural dexmedetomidine (0.5 μg·kg-1) may be a more appropriate choice.

Clinical Trial Registration

Chinese Clinical Trial Registry (ChiCTR2200058982).

Serum Levels of Bupivacaine After Bilateral Ultrasound-Guided Deep Parasternal Intercostal Plane Block in Cardiac Surgery with Median Sternotomy

OBJECTIVE

To evaluate systemic levels of bupivacaine after bilateral ultrasound-guided deep parasternal intercostal plan (PIP) block in cardiac surgical patients undergoing median sternotomy.

DESIGN

Prospective, observational study SETTING: Single institution; academic university hospital PARTICIPANTS: Twenty-eight adult patients undergoing cardiac surgery with median sternotomy received a PIP block with 2.5 mg/kg bupivacaine with or without dexamethasone and dexmedetomidine.

MEASUREMENTS

Arterial blood samples were analyzed for total serum bupivacaine concentration at 5, 15, 30, 45, 60, 90, 120, and 150 minutes after placement of PIP. Local anesthetic volume, local anesthetic adjuncts, time to extubation, postoperative pain scores, and opioid consumption were recorded.

MAIN RESULTS

The mean peak bupivacaine concentration was 0.60 ± 0.62 µg/mL, and the mean time to maximum concentration (Tmax) was 16.92 ± 12.97 minutes. Two patients (7.1%) had a concentration >2.0 µg/mL within 15 minutes of block placement. The mean Tmax of bupivacaine was significantly greater in patients who did not receive additives compared to those patients who did (22.86 ± 14.77 minutes v 10.0 ± 5.22 minutes; p = .004). The times to extubation and postoperative pain were not improved with additives.

CONCLUSIONS

Bilateral PIP placed at the end of cardiac surgery resulted in low systemic bupivacaine levels. The inclusion of additives shortened Tmax without improving outcome.

Injectable Hydrogel Delivery System with High Drug Loading for Prolonging Local Anesthesia

Peripheral nerve block is performed for precise pain control and lesser side effects after surgery by reducing opioid consumption. Injectable hydrogel delivery systems with high biosafety and moisture content have good clinical application prospects for local anesthetic delivery. However, how to achieve high drug loading and long-term controlled release of water-soluble narcotic drugs remains a big challenge. In this study, heterogeneous microspheres and an injectable gel-matrix composite drug delivery system are designed in two steps. First, heterogeneous hydrogel microspheres loaded with ropivacaine (HMS-ROP) are prepared using a microfluidic chip and in situ alkalization. An injectable self-healing hydrogel matrix (Gel) is then prepared from modified carboxymethylcellulose (CMC-ADH) and oxidized hyaluronic acid (OHA). A local anesthetic delivery system, Gel/HMS-ROP/dexmedetomidine (DEX), with long-term retention and drug release in vivo is prepared by combining HMS-ROP and Gel/DEX. The drug loading of HMS-ROP reached 41.1%, with a drug release time of over 160 h in vitro, and sensory and motor blockade times in vivo of 48 and 36 h, respectively. In summary, the sequential release and synergistic analgesic effects of the two anesthetics are realized using core-shell microspheres, DEX, and an injectable gel, providing a promising strategy for long-acting postoperative pain management.

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.

0.25% bupivacaine-1% lidocaine vs 0.5% bupivacaine for ultrasound-guided infraclavicular brachial plexus block: a randomized controlled trial

INTRODUCTION

In an effort to shorten onset time, a common practice is to add lidocaine to bupivacaine. In the setting of infraclavicular block, it is unclear what the block characteristics of this practice are compared with bupivacaine alone. We hypothesized that bupivacaine alone increases the duration of motor block, sensory block, and postoperative analgesia while resulting in a slower onset time compared with a bupivacaine and lidocaine mixture.

METHODS

40 patients receiving ultrasound-guided infraclavicular brachial plexus block were randomly assigned to receive either 35 mL of 0.25% bupivacaine and 1% lidocaine or 0.5% bupivacaine, both associated with perineural adjuvants (epinephrine 5 µg/mL and dexamethasone 4 mg). After the block was performed, a blinded observer evaluated the success of the block, the onset time, and the incidence of surgical anesthesia. Postoperatively, a blinded observer contacted patients who had successful blocks to inquire about the duration of motor block, sensory block, postoperative analgesia, and the presence of rebound pain.

RESULTS

When comparing patients having bupivacaine alone versus bupivacaine and lidocaine, the mean (SD) motor block duration was 28.4 (5.2) vs 18.9 (3.1) hours, respectively; the mean difference 9.5 hours (95% CI 6.5 to 12.4; p<0.001); the mean (SD) sensory block duration was 29.3 (5.8) vs 18.7 (4.0) hours, respectively; the mean difference 10.6 hours (95% CI 7.1 to 14.0; p<0.001); the mean (SD) postoperative analgesia duration was 38.3 (7.4) vs 24.3 (6.6) hours, respectively; the mean difference 14 hours (95% CI 9.2 to 18.8; p<0.001); and the median (IQR) onset time was 35 (15) vs 20 (10) min, respectively; p<0.001. No other significant differences were detected.

CONCLUSIONS

Compared with mixed bupivacaine-lidocaine, 0.5% bupivacaine significantly prolongs sensorimotor block and postoperative analgesia at the expense of a delayed onset time.

TRIAL REGISTRATION NUMBER

NCT05834023.

Peripheral nerve block and cognitive impairment after thoracic surgery: a systematic review and meta-analysis

INTRODUCTION

Postoperative cognitive impairment is common in surgical patients, including postoperative delirium and postoperative cognitive dysfunction. Several studies investigating the association between peripheral nerve block and the risk of cognitive impairment after thoracic surgery showed conflicting results. Therefore, we conducted the current systematic review and meta-analysis to determine the effects of peripheral nerve block on postoperative cognitive impairment in thoracic surgical patients.

EVIDENCE ACQUISITION

Eligible randomized controlled trials were retrieved from PubMed, Cochrane Library, Web of Science and Embase databases. The primary outcomes were the incidence of postoperative delirium or cognitive dysfunction and the MMSE scores. Furthermore, VAS scores, levels of TNF-α and IL-6, as well as the duration of hospitalization were analyzed as secondary outcomes.

EVIDENCE SYNTHESIS

Ten articles including 1279 participants were selected for this meta-analysis. The results showed that peripheral nerve block could lessen the incidence of postoperative delirium or cognitive dysfunction (OR=0.39, 95% CI [0.27 to 0.56]), the scores of VAS (MD=-1.35 [95% CI: -2.30 to -0.40]), the values of TNF-α (SMD=-1.13 [95% CI: -1.49 to -0.76]) and IL-6 (SMD=-1.65 [95% CI: -1.87 to -1.42]), as well as the length of hospitalization (MD=-0.70 [95% CI: -0.96 to -0.43]). In addition, peripheral nerve block was linked to a significant increase in MMSE scores (MD=2.16 [95% CI: 1.40 to 2.91]).

CONCLUSIONS

This meta-analysis revealed positive effects of peripheral nerve block on improving postoperative cognitive impairment in patients following thoracic surgery.

Comparative Study Between Dexmedetomidine with Bupivacaine and Bupivacaine Alone in Erector Spinae Plane Block for Postoperative Pain Control of Posterior Lumbosacral Spine Fixation Surgeries: A Randomized Controlled Trial

Background

As posterior lumbosacral spine fixation surgeries are common spine procedures done nowadays due to different causes and mostly accompanied with moderate-to-severe postoperative pain, so should find effective postoperative analgesia for these patients. This study aimed to observe analgesic effect of dexmedetomidine combined with bupivacaine versus bupivacaine alone for erector spinae plane block ESPB for postoperative pain control of posterior lumbosacral spine fixation surgeries.

Methods

Double-blind randomized controlled study including 90 patients who were randomly allocated into 3 groups (30 patients for each): Dexmedetomidine combined with bupivacaine (DB group), bupivacaine (B group), and saline (control) (S group). US-guided ESPB was performed preoperatively bilaterally in all patients of the 3 groups. All patients received intravenous patient-controlled postoperative analgesia with morphine and 1 gm intravenous paracetamol every 8 hours. Primary clinical outcomes were active (while mobilization) and passive (at rest) visual analog scale (VAS) pain score at first 24 hours measured every 2 hours, opioid consumption (number of PCA presses), and need for rescue analgesia. Other clinical outcomes included active and passive VAS pain score at second 24 hours, measured every 4 hours, opioid consumption, need for rescue analgesia, postoperative opioid side effects, and intraoperative dexmedetomidine side effects as bradycardia and hypotension.

Results

Active and passive VAS pain scores, postoperative opioid consumption, need for rescue analgesia, and postoperative opioid side effects were significantly lower in DB group when compared to other groups (B and S groups). There were no additional intraoperative dexmedetomidine side effects as bradycardia and hypotension. The estimated effect-size r was -0.58 and Cohen's d was -1.46.

Conclusion

Addition of dexmedetomidine to bupivacaine 0.25% in ESPB for postoperative pain control in patients of posterior lumbosacral spine fixation surgeries resulted in lower active and passive VAS pain scores, decreased postoperative opioid consumption, need for rescue analgesia and postoperative opioid side effects without additional intraoperative dexmedetomidine side effects.

Clinicaltrialsgov Identifier

NCT05590234.

Regional Anesthesia for Arthroscopic Knee Repair in a Patient With Hypertrophic Obstructive Cardiomyopathy (HOCM) Under Monitored Anesthesia Care With Dexmedetomidine Infusion

Patients with hypertrophic obstructive cardiomyopathy (HOCM) who are scheduled for elective, noncardiac surgery present a distinctive challenge for perioperative healthcare providers. The use of general anesthesia and neuraxial anesthesia carries the risk of unpredictable hemodynamic changes and potential complications. Regional anesthesia (RA) emerges as a prudent and effective option for HOCM patients. RA provides advantages such as minimizing hemodynamic fluctuations, avoiding intubation, reducing pharmacologic side effects, facilitating enhanced recovery after surgery, and contributing to greater patient satisfaction. We share the case of a 15-year-old individual diagnosed with HOCM and exercise intolerance, undergoing arthroscopic repair for right patellar instability. In this instance, the patient received preoperative peripheral nerve blocks for surgical anesthesia and underwent repair utilizing monitored anesthesia care (MAC) with a dexmedetomidine (DEX) infusion.

Modulating Hyperpolarization-Activated Cation Currents through Small Molecule Perturbations: Magnitude and Gating Control

The hyperpolarization-activated cation current (Ih) exhibits a slowly activating time course of the current (Ih) when the cell membrane is hyperpolarized for an extended duration. It is involved in generating electrical activity in various excitable cells. Numerous structurally distinct compounds or herbal drugs have the potential to impact both the magnitude and gating kinetics of this current. Brivaracetam, a chemical analog of levetiracetam known to be a ligand for synaptic vesicle protein 2A, could directly suppress the Ih magnitude. Carisbamate, an anticonvulsant agent, not only inhibited the Ih amplitude but also reduced the strength of voltage-dependent hysteresis (Hys(V)) associated with Ih. Cilobradine, similar to ivabradine, inhibited the amplitude of Ih; however, it also suppressed the amplitude of delayed-rectifier K+ currents. Dexmedetomidine, an agonist of α2-adrenergic receptor, exerted a depressant action on Ih in a concentration-dependent fashion. Suppression of Ih amplitude was observed when GAL-021, a breathing control modulator, was present at a concentration exceeding 30 μM. Lutein, one of the few xanthophyll carotenoids, was able to suppress the Ih amplitude as well as to depress Hys(V)'s strength of Ih. Pirfenidone, a pyridine derivative known to be an anti-fibrotic agent, depressed the Ih magnitude in a concentration- and voltage-dependent fashion. Tramadol, a synthetic centrally active analgesic, was shown to reduce the Ih magnitude, independent of its interaction with opioid receptors. Various herbal drugs, including ent-kaurane-type diterpenoids from Croton tonkinensis, Ganoderma triterpenoids, honokiol, and pterostilbene, demonstrated efficacy in reducing the magnitude of Ih. Conversely, oxaliplatin, a platinum-based chemotherapeutic compound, was observed to effectively increase the Ih amplitude. Collectively, the regulatory effects of these compounds or herbal drugs on cellular function can be partly attributed to their perturbations on Ih.