Epidural dexmedetomidine infusion for perioperative analgesia in patients undergoing abdominal cancer surgery: randomized trial

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 Influence of Dexmedetomidine as an Adjuvant in Intrathecal Labor Analgesia: A Multicenter Study on Efficacy and Maternal Satisfaction

In this study, we examined the impact of dexmedetomidine (DEX) on the effectiveness of epidural analgesia and labor outcomes. We administered different doses of DEX combined with 0.1% ropivacaine for epidural analgesia to evaluate the clinical effects and safety. To assess the effects of different concentrations of DEX in parturient women receiving epidural analgesia, we conducted a randomized double-blind trial. We selected 400 parturient women and randomly assigned them to 4 groups, with 100 parturient women in each group: S0.1 (0.1 µg/mL DEX), S0.2 (0.2 µg/mL DEX), S0.3 (0.3 µg/mL DEX), and a control group (0.3 µg/mL sufentanil). Post-analgesia, we recorded the Bromage score, duration of labor, method of delivery, bleeding, neonatal Apgar score, adverse reactions, and maternal satisfaction. The number of patients with a Bromage score of ≥2 and the incidence of bradycardia were higher in the S0.3 group compared with the other 3 groups (P < .05), whereas the high satisfaction rate was lower in the S0.3 group (P < .05). Moreover, we found that the number of times that additional patient-controlled analgesia was administered was higher in the S0.1 group compared with the remaining 3 groups (P < .05). The control group exhibited a higher incidence of pruritus than the other 3 groups (P < .05). In conclusion, when administering spinal anesthesia for the relief of labor pain, epidural analgesia with 0.1% ropivacaine combined with 0.2 µg/mL DEX provides relatively ideal analgesic effects, higher maternal satisfaction, and reduces the incidence of pruritus, compared with the combination of 0.1% ropivacaine and 0.3 µg/mL sufentanil.

Application Effect of Dexmedetomidine and Dezocine in Patients Undergoing Lung Cancer Surgery under General Anesthesia and Analysis of Their Roles in Recovery Time and Cognitive Function

Objective. To explore the application influence of dexmedetomidine (DEX) and dezocine in patients undergoing lung cancer surgery under general anesthesia and analysis of their roles in recovery time and cognitive function. Methods. A total of 120 patients who accepted thoracoscopic pulmonary wedge resection in our hospital from November 2021 to April 2022 were selected and randomly divided into group A ( $n$  =60) and group B ( $n$  =60). DEX combined with dezocine-assisted anesthesia was performed to group A, and the equal dose of normal saline was administered to group B, so as to compare their inflammatory influence level, brain function, arterial blood gas index, and cognitive function. Results. Compared with group B, group A obtained significantly lower intraoperative and postoperative inflammatory factor levels ( $P<0.001$ ), better postoperative brain function and arterial blood gas index ( $P<0.001$ ), and lower Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) scores after surgery ( $P<0.001$ ). Combining DEX with dezocine-assisted general anesthesia can improve the inflammatory factors level of patients undergoing lung cancer surgery and maintain their brain function and oxygen saturation, so that they have better postoperative cognitive function. Therefore, such anesthesia modality should be promoted in practice.

Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has sedative, anxiolytic, analgesic, sympatholytic, and opioid-sparing properties and induces a unique sedative response which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Recent studies indicate several emerging clinical applications via different routes. We review recent data on dexmedetomidine studies, particularly exploring the varying routes of administration, experimental implications, clinical effects, and comparative advantages over other drugs. A search was conducted on the PubMed and Web of Science libraries for recent studies using different combinations of the words “dexmedetomidine”, “route of administration”, and pharmacological effect. The current routes, pharmacological effects, and application categories of dexmedetomidine are presented. It functions by stimulating pre- and post-synaptic α2-adrenoreceptors within the central nervous system, leading to hyperpolarization of noradrenergic neurons, induction of an inhibitory feedback loop, and reduction of norepinephrine secretion, causing a sympatholytic effect, in addition to its anti-inflammation, sleep induction, bowel recovery, and sore throat reduction effects. Compared with similar α2-adrenoceptor agonists, dexmedetomidine has both pharmacodynamics advantage of a significantly greater α2:α1-adrenoceptor affinity ratio and a pharmacokinetic advantage of having a significantly shorter elimination half-life. In its clinical application, dexmedetomidine has been reported to present a significant number of benefits including safe sedation for various surgical interventions, improvement of intraoperative and postoperative analgesia, sedation for compromised airways without respiratory depression, nephroprotection and stability of hypotensive hemodynamics, reduction of postoperative nausea and vomiting and postoperative shivering incidence, and decrease of intraoperative blood loss. Although the clinical application of dexmedetomidine is promising, it is still limited and further research is required to enhance understanding of its pharmacological properties, patient selection, dosage, and adverse effects.

Continuous infusion of intraoperative dexmedetomidine improves chronic pain after thoracotomy via the Toll-like receptor 4/nuclear factor kappa B signaling pathway

OBJECTIVES

To explore the role of continuous infusion of intraoperative dexmedetomidine in chronic pain after thoracotomy via the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway.

METHODS

Seventy-five patients undergoing thoracotomy were randomized into the control group (CG, n=37) and the observation group (OG, n=38). After induction of anesthesia for 30 min and until the end of surgery, the OG was infused with 0.4 μg/(kg·h) dexmedetomidine, and the CG was infused with the same amount of normal saline.

RESULTS

After operation, the OG had lower mean arterial pressure, heart rate, visual analogue scale (VAS) scores, incidence of chronic pain and neuropathic pain, TLR4 and NF-κB expressions, and tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels as well as epinephrine and norepinephrine levels than the CG (P < 0.05). The number of times the patient pressed the button for pain medication and the dose administered in the OG were less than those in the CG (P < 0.05).

CONCLUSION

Continuous infusion of intraoperative dexmedetomidine can maintain perioperative hemodynamic stability in patients undergoing thoracotomy and reduce the stress response, postoperative pain, consumption of analgesic drugs, and the incidence of post-chronic and neuropathic pain, which is closely related to the reduction of inflammation via the TLR4/NF-κB signaling pathway.

Efficacy of Dexmedetomidine Versus Morphine as an Adjunct to Bupivacaine in Caudal Anesthesia for Pediatric Thoracic Surgeries: A Randomized Controlled Trial

Background

Caudal anesthesia is an effective method of pain management, which can be successfully employed to minimize post-thoracotomy pain in pediatric patients. However, its main disadvantage is the short postoperative analgesic period, which can be prolonged by the concurrent administration of one of many adjuvants.

Objectives

This prospective randomized, blinded study aimed to compare the efficacy of dexmedetomidine versus morphine as adjuvants to bupivacaine in caudal anesthesia for thoracic surgeries in pediatric patients.

Methods

Fifty patients were randomly allocated into two equal groups. To achieve caudal epidural block anesthesia, the patients in group M (n = 25) were administered morphine and bupivacaine, while group D (n = 25) received a mixture of dexmedetomidine and bupivacaine. The primary outcome of this study was the postoperative analgesic duration achieved. The secondary outcomes included morphine administration in the first 24 hours following caudal block anesthesia, the face, legs, activity, cry, consolability (FLACC) scale scores, and adverse effects, including vomiting, itching, bradycardia, hypotension, and respiratory depression.

Results

The results showed that patients who had received dexmedetomidine achieved a longer postoperative analgesia as compared to those who had received morphine (P < 0.001). Postoperatively, the heart rate, blood pressure, pain score, and mean consumption of morphine were lower in group D as compared to the group M. There was no significant difference in the adverse effects between the two groups.

Conclusions

The use of dexmedetomidine as an adjuvant to bupivacaine for caudal anesthesia during pediatric thoracic surgeries induced better and prolonged postoperative analgesia as compared to morphine.

Influence of Epidural Ropivacaine with or without Dexmedetomidine on Postoperative Analgesia and Patient Satisfaction after Thoraco-Lumbar Spine Instrumentation: A Randomized, Comparative, and Double-Blind Study

Study Design

This was a prospective, randomized, and double-blind study.

Purpose

Thoraco-lumbar spine surgery is associated with severe postoperative pain and can cause chronic pain. We aimed to compare the impact of epidural ropivacaine with and without dexmedetomidine on postoperative analgesia after thoracolumbar spine instrumentation wherein an epidural catheter was placed by the surgeon intraoperatively.

Overview of Literature

Very few studies have reported the use of epidural dexmedetomidine in spine surgeries. When used via the epidural route, dexmedetomidine is safe and efficacious and is associated with reduced rescue analgesia consumption, increased duration of analgesia, reduced pain scores, but not with major hemodynamic adverse effects.

Methods

Total 60 American Society of Anesthesiologists I–III adult patients aged 18–65 years who were scheduled to undergo thoraco-lumbar spine instrumentation were randomly allocated into group RD (epidural ropivacaine+dexmedetomidine) or group R (epidural ropivacaine plus saline). We aimed to compare the total rescue analgesic consumption on postoperative day 0, 1, and 2. Moreover, we studied the time to first rescue analgesia with visual analogue scale score <4 and the overall patient satisfaction scores.

Results

There was no difference between the demographic characteristics of the two groups. The mean value of total rescue analgesia consumption was 162.5±68.4 mg in the RD group and 247.5±48.8 mg in the R group. The mean time to first rescue analgesia was 594.6±83.0 minutes in the RD group and 103.6±53.2 minutes in the R group. The mean patient satisfaction score was 4.2±0.7 in the RD group and 3.2±0.6 in the R group. No patient had any respiratory depression or prolonged motor blockade during the postoperative period.

Conclusions

This study demonstrated the superior efficacy, in terms of postoperative analgesia and patient satisfaction scores, of epidural ropivacaine plus dexmedetomidine over that of ropivacaine alone in patients undergoing surgery for thoraco-lumbar spine.

Ultrasound-guided transversus abdominis plane block using ropivacaine and dexmedetomidine in patients undergoing caesarian sections to relieve post-operative analgesia: A randomized controlled clinical trial

Dexmedetomidine, which is a highly selective α2 adrenoreceptor agonist, enhances the analgesic efficacy and prolongs the analgesic duration when administered in combination with local anesthetics. The current study aimed to evaluate the effects of dexmedetomidine combined with ropivacaine in ultrasound-guided transversus abdominis plane (TAP) block on post-operative analgesia following cesarean section (CS). A total of 70 patients scheduled for CS were divided randomly into 2 groups: The ropivacaine (R) group, in which patients were administered bilateral 20 ml 0.3% ropivacaine and 2 ml 0.9% normal saline, and the dexmedetomidine (RD) group, in which patients were administered bilateral 20 ml 0.3% ropivacaine and 2 ml dexmedetomidine (0.5 µg/kg). The primary outcome was pain-free duration, and secondary outcomes included heart rate (HR) and mean blood pressure (MBP) measurements, visual analogue scale (VAS) pain scores, number of patients who required rescue analgesic, time to first request for analgesia and patient satisfaction. There was no significant difference in HR and MBP between the two groups at 1 h post-surgery (P>0.05). However, VAS pain scores decreased at 6 and 8 h post-surgery [2 (1-2) vs. 0 (0-0.25) and 2 (2-3) vs. 0 (0-1), respectively; P<0.05], pain-free duration was prolonged (5.91±1.08 vs. 9.62±1.46 h; P<0.05), the number of patients who required rescue analgesic was reduced (19 vs. 9; P<0.05), the time to first request for analgesia was prolonged (7.10±1.21 vs. 11.60±2.11 h; P<0.05) and patient satisfaction was improved [3.5 (3-4) vs. 4 (4-5); P<0.05] in the RD group compared with the R group. Furthermore, no bradycardia or hypotension was observed. In conclusion, the results of the present study demonstrated that adding 0.5 µg/kg dexmedetomidine to 0.3% ropivacaine used in TAP block in patients undergoing CS prolonged pain-free duration, decreased VAS pain scores, reduced the number of patients who required rescue analgesic, prolonged the time to first request for analgesia and improved the patient satisfaction without serious side effects.

Epidural dexmedetomidine infusion in a patient with chronic opioid use and intractable pain following abdominoperineal resection

Dexmedetomidine is a selective alpha 2 adrenergic agonist with known analgesic properties. Its perioperative use is associated with reduced pain scores and an opioid sparing effect. Management of postoperative pain in patients with a history of chronic opioid use can be challenging. Multimodal analgesia is recommended although the perioperative use of dexmedetomidine has not been extensively studied in this patient population. We present a case of intractable abdominal pain following open abdominoperineal resection in a patient with rectal cancer and a history of chronic opioid use. Following the introduction of dexmedetomidine into the patient’s postoperative epidural solution, a noticeable decline in reported pain scores and use of breakthrough analgesia was appreciated. The analgesic efficacy of epidural dexmedetomidine in patients with a history of chronic opioid use warrants further study.

Addition of dexmedetomidine to epidural morphine to improve anesthesia and analgesia for cesarean section

The aim of the present study was to evaluate the effectiveness and safety of the combination of epidural dexmedetomidine and morphine in providing anesthesia during cesarean surgery and analgesia for post-cesarean pain relief when added to epidural ropivacaine. A total of 80 females at term scheduled for elective cesarean delivery were randomly assigned to two groups (n=40/group): In the morphine group (group M), patients received an epidural injection of 0.75% ropivacaine (12 ml) and morphine (2 mg) for surgical anesthesia, and epidural infusion of morphine (2 mg) in 100 ml 0.2% ropivacaine at 2 ml/h for 48-h post-operative analgesia; and in the morphine combined with dexmedetomidine group (group DM), patients received an epidural injection of 0.75% ropivacaine (12 ml) and morphine (2 mg) combined with dexmedetomidine (0.5 µg/kg) for surgical anesthesia, and epidural infusion of morphine (2 mg) and dexmedetomidine (200 µg) in 100 ml 0.2% ropivacaine at 2 ml/h for 48-h post-operative analgesia. The primary outcomes included blockade and analgesic effects, sedation and adverse reactions associated with the drugs. Neonatal outcome was also assessed by determining the Apgar score and umbilical cord blood analysis. There was no significant difference between the groups in the cephalad levels of sensory blockade at 20 min post-injection, or in muscle relaxation scores or pain intensity scores at rest or upon movement at 4, 12, 24 or 48 h post-injection (P>0.05). The maternal patients in the DM group experienced more complete motor blockade at 20 min post-injection, better sedation during surgery and following delivery, and less visceral pain caused by peritoneal traction during surgery and by uterine contraction after delivery, compared with those in group M (P<0.05). The patients in group M had a lower incidence and severity score of post-operative nausea than those in the DM group (P<0.05). There was no significant difference between the groups in terms of Apgar score or umbilical cord blood gas values (P>0.05). In conclusion, epidural dexmedetomidine reduces intra-operative and post-operative visceral pain and produces better sedation during surgery and following delivery, without any significant influence on morphine-associated side effects and post-operative analgesia, in females undergoing elective cesarean section under epidural anesthesia with morphine and ropivacaine (registration number ChiCTR1900027942; retrospectively registered with the Chinese Clinical Registry Center on December 6, 2019).

Comparison of Dexmedetomidine and Morphine as Adjuvants to Bupivacaine for Epidural Anesthesia in Leg Fracture Surgery: A Randomized Clinical Trial

Background

Epidural block approach and drugs are common options for improving the sensory and motor block duration and postoperative pain management.

Objectives

The study aimed to compare the analgesic effects of dexmedetomidine and morphine as adjuvants to bupivacaine for epidural anesthesia in leg fracture surgery.

Methods

This prospective clinical trial was conducted on patients (n = 80, age range: 18 - 60 years) categorized as ASA class I or II. After a clinical examination, the patients were allocated to receive either lumbar epidural bupivacaine + morphine (BM) (12 mL bupivacaine 0.5% + morphine 2 mg) or bupivacaine + dexmedetomidine (BD) (12 mL bupivacaine 0.5% + dexmedetomidine 1 µg/kg). After drug administration, the sensory block level was assessed at 2-min intervals using the Cold Swab method until it reached the T12 level. At the T12 level of sensory block, the surgery began when motor block reached grade 3 of the modified Bromage scale.

Results

The BD group had a significantly shorter time to reach the sensory and motor block than the BM group (P < 0.001). The duration of sensory and motor block was significantly longer in the group BD than in the BM group (P < 0.001). Moreover, the BD group showed lower VAS scores (P < 0.0001) and longer time to first analgesia demand than the BM group.

Conclusions

Combined bupivacaine + dexmedetomidine prolongs the sensory and motor block duration and controls postoperative pain more effectively, indicating that it is an appropriate combination for epidural anesthesia.

Multimodal Analgesia for Perioperative Management of Patients presenting for Spinal Surgery

Multimodal, non-opioid based analgesia has become the cornerstone of ERAS protocols for effective analgesia after spinal surgery. Opioid side effects, dependence and legislation restricting long term opioid use has led to a resurgence in interest in opioid sparing techniques. The increasing array of multimodal opioid sparing analgesics available for spinal surgery targeting novel receptors, transmitters, and altering epigenetics can help provide an optimal perioperative experience with less opioid side effects and long-term dependence. Epigenetic mechanisms of pain may enhance or suppress gene expression, without altering the genome itself. Such mechanisms are complex, dynamic and responsive to environment. Alterations that occur can affect the pathophysiology of pain management at a DNA level, modifying perceived pain relief. In this review, we provide a brief overview of epigenetics of pain, systemic local anesthetics and neuraxial techniques that continue to remain useful for spinal surgery, neuropathic agents, as well as other common and less common target receptors for a truly multimodal approach to perioperative pain management.