Trial watch: dexmedetomidine in cancer therapy

Dexmedetomidine (DEX) is a highly selective α2-adrenoceptor agonist that is widely used in intensive and anesthetic care for its sedative and anxiolytic properties. DEX has the capacity to alleviate inflammatory pain while limiting immunosuppressive glucocorticoid stress during major surgery, thus harboring therapeutic benefits for oncological procedures. Recently, the molecular mechanisms of DEX-mediated anticancer effects have been partially deciphered. Together with additional preclinical data, these mechanistic insights support the hypothesis that DEX-induced therapeutic benefits are mediated via the stimulation of adaptive anti-tumor immune responses. Similarly, published clinical trials including ancillary studies described an immunostimulatory role of DEX during the perioperative period of cancer surgery. The impact of DEX on long-term patient survival remains elusive. Nevertheless, DEX-mediated immunostimulation offers an interesting therapeutic option for onco-anesthesia. Our present review comprehensively summarizes data from preclinical and clinical studies as well as from ongoing trials with a distinct focus on the role of DEX in overcoming (tumor microenvironment (TME)-imposed) cancer therapy resistance. The objective of this update is to guide clinicians in their choice toward immunostimulatory onco-anesthetic agents that have the capacity to improve disease outcome.

Periarticular infiltration used in total joint replacements: an update and review article

Periarticular infiltration following total knee and hip arthroplasty has been demonstrated to be equivalent to peripheral nerve blocks for postoperative pain management. The ideal cocktail has not been established yet. We have conducted a literature search on PubMed and Embase. Our search criteria included randomized controlled trials (RCTs) and systematic reviews (SRs). We tried to only include the most recent studies to keep the information current. The included research focused at Dexmedetomidine, Liposomal Bupivacaine, Ropivacaine, Epinephrine, Ketorolac, Morphine, Ketamine and Glucocorticosteroids. Each medication's mode of action, duration, ideal dosage, contraindications, side effects and effectiveness have been summarized in the review article. This article will help the clinician to make an informed evidence-based decision about which medications to include in their ideal cocktail.

Effect of Local Ketamine Subcutaneous Injection at the Incision Site in Reducing the Postoperative Pain Score after Transabdominal Hysterectomy

Background

Pain control after operations is essential in decreasing the patient recovery period and potential morbidity. Prescribing opiates is very effective, but significant side effects accompany them. This study aims to examine the effect of local ketamine infiltration in decreasing pain intensity in patients undergoing transabdominal hysterectomy.

Methods

In this double-blind, randomized, controlled clinical trial, a total of 92 patients undergoing transabdominal hysterectomy aged 30-60 years were selected and divided into two intervention and control groups randomly. For the intervention group, ketamine was injected subcutaneously into the incision site at a dose of 0.5 mg/kg after the operation. In the control group, 5 mg normal saline was used in the same method. Postoperative pain intensity was measured using the visual analog scale (VAS: 0-10). The pain score and dose of administered opioids were documented at 1, 2, 4, 6, 12, and 24 hours and compared between the two groups.

Results

Postoperative pain intensity was significantly lower in the intervention group than in the control group, except for hour 24. The mean amounts of administered opioids were significantly lower in the intervention group at hours 6 and 12, as well as the total amount of used opioids, and no significant side effects were documented.

Conclusion

Local ketamine subcutaneous injection in the incisional site is effective and is a safe procedure for reducing pain scores in patients who underwent a transabdominal hysterectomy.

Dexamethasone and dexmedetomidine as adjuvants to ropivacaine do not prolong analgesia in wound infiltration for lumbar spinal fusion: a prospective randomized controlled study

BACKGROUND AND OBJECTIVES

Local anesthetics (LAs) are widely used to infiltrate into surgical wounds for postoperative analgesia. Different adjuvants like dexamethasone and dexmedetomidine, when added to LA agents, could improve and prolong analgesia. The aim of this trial was to evaluate the analgesic efficacy and opioid-sparing properties of dexamethasone and dexmedetomidine when added to ropivacaine for wound infiltration in transforaminal lumbar interbody fusion (TLIF).

METHODS

We conducted a controlled study among 68 adult patients undergoing TLIF, which was prospective, randomized and double-blind in nature. The participants were divided into four equal groups at random. Group R was given 150 mg of 1% ropivacaine (15 mL) and 15 mL of normal saline. Group R + DXM received 150 mg of 1% ropivacaine (15 mL) and 10 mg of dexamethasone (15 mL). Group R + DEX received 150 mg of 1% ropivacaine (15 mL) and 1 µg/kg of dexmedetomidine (15 mL). Lastly, group R + DXM + DEX was given 150 mg of 1% ropivacaine (15 mL), 10 mg of dexamethasone and 1 µg/kg of dexmedetomidine (15 mL). The primary focus was on the length of pain relief provided. Additionally, secondary evaluations included the amount of hydromorphone taken after surgery, the numerical rating scale and safety assessments within 48 h after the operation.

RESULTS

Based on the p value (P > 0.05), there was no significant variance in the duration of pain relief or the total usage of hydromorphone after surgery across the four groups. Similarly, the numerical rating scale scores at rest and during activity at 6-, 12-, 24- and 48-h post-surgery for all four groups showed no difference (P > 0.05). However, the incidence of delayed anesthesia recovery was slightly higher in group R + DEX and group R + DXM + DEX when compared to group R or group R + DXM. Furthermore, there were no significant differences between the four groups in terms of vomiting, nausea, dizziness or delayed anesthesia recovery.

CONCLUSION

For wound infiltration in TLIF, the addition of dexamethasone and dexmedetomidine to ropivacaine did not result in any clinically significant reduction in pain or opioid consumption and could prompt some side effects.

Dexmedetomidine Prolongs the Analgesic Effects of Periarticular Infiltration Analgesia following Total Knee Arthroplasty: A Prospective, Double-blind, Randomized Controlled Trial

BACKGROUND

Periarticular infiltration analgesia (PIA) is widely administered to relieve postoperative pain following total knee arthroplasty (TKA). The present study aimed to evaluate the effect of prolonging the analgesic duration by adding dexmedetomidine to PIA for pain management after TKA.

METHODS

One hundred and sixteen patients were randomly allocated into 3 groups based on PIA regimens including Group R (ropivacaine), Group E (ropivacaine plus epinephrine), and Group D (ropivacaine plus dexmedetomidine). The primary outcomes were postoperative visual analog scale (VAS) scores, time until the administration of first rescue analgesia, and opioid consumption. The secondary outcomes included postoperative inflammatory biomarkers and functional recovery. The tertiary outcomes were postoperative complications and adverse events.

RESULTS

The patients in Group D had significantly lower resting VAS scores than those in Groups R and E at 6 hours after surgery. Group R showed the higher pain scores at rest and motion than Groups D and E 12 hours postoperatively. The use of dexmedetomidine or epinephrine postponed the time until the administration of first rescue analgesia and led to lower opioid consumption in the first 24 hours after TKA. The levels of IL-8 and TNF-α in Groups D and E were significantly lower than those in Group R on postoperative Day 3. Furthermore, no significant differences were observed in functional recovery, postoperative complications, or adverse events among the three groups.

CONCLUSIONS

Adding dexmedetomidine as an adjuvant to PIA could potentiate and prolong the analgesic effect in the early stage following TKA without increasing the risk of adverse events.

Does Treatment with Dexmedetomidine Intra-articularly Improve Postoperative Pain and Rehabilitation after Anterior Cruciate Ligament Reconstruction?

This study aims to evaluate the analgesic efficacy of dexmedetomidine added to levobupivacaine following anterior cruciate ligament (ACL) surgery. Fifty patients undergoing ACL reconstruction were included. Group DL (dexmedetomidin-levobupivacaine) received 20 mL 0.5% levobupivacaine plus 1 mL (100 μg) dexmedetomidine. Group L (levobupivacaine) patients received 20 mL 0.5% levobupivacaine plus 1 mL saline 10 minutes before tourniquet release. A patient-controlled analgesia (PCA) pump was then connected, delivering 0.5 mg at every 10 minutes and 1-mg morphine and 75-mg diclofenac sodium was used as a rescue analgesic. Postoperative pain was evaluated 0, 2, 4, 6, 12, and 24 hours after extubation at rest and during movement. A rehabilitation program was started after surgery. Postoperative continuous passive motion (CPM) starting time, postoperative leg flexion angle, and straight leg lifting time were evaluated for each group. There were no significant differences between the groups in terms of demographic data and operation time. Morphine consumption, analgesic requirements, and visual analogue scale (VAS) assessments were significantly lower in group DL during the 24-hour period after surgery. The time to start CPM in the postoperative period was significantly shorter in group DL. Passive joint flexion angle was significantly higher in group DL. Postoperative straight leg lifting time was significantly shorter in group DL. Adding dexmedetomidine to the intra-articular levobupivacaine provided better postoperative pain control and improved rehabilitation period after ACL surgery.

The Effects of Intravenous Vitamin C on Stress Response Severity in Abdominal Hysterectomy Following Prolonged Fasting Time

Background

Inevitable prolonged fasting time before surgery leads to inflammatory reactions, surgery-related stress response, and consequently unfavorable outcomes; thus, developing strategies to mitigate these consequences is crucial.

Objectives

In this study, we evaluated the effect of ascorbic acid on stress response reduction in abdominal hysterectomy following prolonged fasting time.

Methods

Eligible women candidates for abdominal hysterectomy following prolonged fasting time were enrolled in the study and divided into 2 groups of vitamin C [group C; 1 g intravenously (IV) before surgery] and placebo (group P). Before induction of anesthesia, C-reactive protein (CRP), mean arterial pressure (MAP), heart rate (HR), and blood sugar (BS) were measured and compared between the 2 groups at 4-point times, 24 and 48 hours immediately after extubation.

Results

Finally, the data of 80 patients were included for the final analysis. A statistically significant difference was observed between the 2 groups in terms of CRP and BS values in T1 CRP serum levels; at the end of the study, CRP values were 0.5 ± 0.55 and 0.92 ± 0.69 in groups C and P, respectively (P = 0.012), and BS levels were 124.12 ± 18.11 and 152.0 ± 17.36 in groups C and P, respectively (P = 0.0001). However, this significant difference was not observed at T2 regarding CRP (P = 0.145) and BS (P = 0.135), as well as at T3 regarding CRP (P = 0.282) and BS (P = 0.213). However, according to both CRP and BS values, the trend of changes from T0 to T3 was significant in the 2 groups (P < 0.0001). Hemodynamic parameters were not significantly different between the 2 groups. No adverse event was reported in the 2 groups.

Conclusions

We found that ascorbic acid could induce short-term positive effects in abdominal hysterectomy following prolonged fasting time. Obviously, the optimal dosage, timing, and specific cases that benefit the most from this intervention should be investigated.

Updates on Wound Infiltration Use for Postoperative Pain Management: A Narrative Review

Local anesthetic wound infiltration (WI) provides anesthesia for minor surgical procedures and improves postoperative analgesia as part of multimodal analgesia after general or regional anesthesia. Although pre-incisional block is preferable, in practice WI is usually done at the end of surgery. WI performed as a continuous modality reduces analgesics, prolongs the duration of analgesia, and enhances the patient’s mobilization in some cases. WI benefits are documented in open abdominal surgeries (Caesarean section, colorectal surgery, abdominal hysterectomy, herniorrhaphy), laparoscopic cholecystectomy, oncological breast surgeries, laminectomy, hallux valgus surgery, and radical prostatectomy. Surgical site infiltration requires knowledge of anatomy and the pain origin for a procedure, systematic extensive infiltration of local anesthetic in various tissue planes under direct visualization before wound closure or subcutaneously along the incision. Because the incidence of local anesthetic systemic toxicity is 11% after subcutaneous WI, appropriate local anesthetic dosing is crucial. The risk of wound infection is related to the infection incidence after each particular surgery. For WI to fully meet patient and physician expectations, mastery of the technique, patient education, appropriate local anesthetic dosing and management of the surgical wound with “aseptic, non-touch” technique are needed.

Low-dose spinal and opioid-free anesthesia in patient with Severe Aortic Stenosis and SARS-CoV-2 infection: Case report

The best anesthesiologic approach to severe AS patient has not been adequately studied in literature. Although the current guidelines have a cautious attitude in this regard, Combined Spinal-Epidural Anesthesia (CSEA) has proved to be a safe technique. Therefore, we would like to provide our experience with a severe AS and COVID-19 patient.

Effects of Full Inhalation of Sevoflurane and Total Intravenous Anesthesia on Hemodynamics, Serum Myocardial Enzymes, and Myocardial Markers in Elderly Patients Undergoing Hysterectomy

Objective

To compare the effects of sevoflurane inhalation and intravenous anesthesia on hemodynamics, serum myocardial enzymes, and myocardial markers in elderly patients undergoing hysterectomy.

Methods

Group A and group B were established randomly regarding a total of 126 elderly patients who underwent an elective hysterectomy. Patients in group A were given full anesthesia with sevoflurane, and patients in group B were given anesthesia with intravenous anesthesia. The operation time, anesthesia time, and recovery time in Postanesthesia Care Unit (PACU) were compared; plasma cortisol concentration, hemodynamics, serum myocardial enzymes, and myocardial markers were detected and compared between the two groups of patients before anesthesia (T₀), after anesthesia (T₁), and after surgery (T₂).

Results

Group A observed a longer extubation time and recovery time in PACU than group B (P < 0.05). Results show a lower systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and plasma cortisol concentration of T₁ by comparison with those of T₀ (P < 0.05), but no significant difference remains in terms of intergroup SBP, DBP, and HR (P > 0.05), and there was no interaction effect of groups and time (P > 0.05). The two groups showed no great disparity in the levels of lactate dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase (CK), and CK-MB as a subtype of CK before surgery between the two groups of patients (P > 0.05). After surgery, LDH, AST, CK, and CK-MB levels in both groups were witnessed a surge, in which group A obtained higher levels of LDH, AST, CK, and CK-MB (all P < 0.05).

Conclusion

Total intravenous anesthesia will not increase the hemodynamic fluctuation of elderly patients undergoing hysterectomy and can reduce the damage to the myocardium of patients with surgical trauma, which can protect the myocardium of elderly patients to a certain extent, so it can be adopted as the optimal anesthesia protocol for surgery.

Early postoperative pain after laparoscopic donor nephrectomy predicts 30-day postoperative infectious complications: a pooled analysis of randomized controlled trials

Our research group recently published a positive association between early postoperative pain and 30-day postoperative complications in a broad surgical population. To investigate whether heterogeneity of the population and surgical procedures influenced these results, we explored this association in a homogenous surgical population. A secondary analysis of the LEOPARD-2 (clinicaltrials.gov NCT02146417) and RELAX-1 study (NCT02838134) in laparoscopic donor nephrectomy patients (n = 160) was performed. Pain scores on the postanesthesia care unit and postoperative day (POD) 1 and 2 were compared between patients with infectious, noninfectious, and no complications 30 days after surgery. Patients who developed infectious complications had significantly higher pain scores on POD1 and 2 (6.7 ± 2.1 and 6.4 ± 2.8) than patients without complications (4.9 ± 2.2 and 4.1 ± 1.9), respectively (P = 0.006 and P = 0.000). Unacceptable pain (numeric rating scale [NRS] ≥ 6) on POD1 was reported by 72% of patients who developed infectious complications, compared to 38% with noninfectious complications and 30% without complications (P = 0.018). This difference was still present on POD2 at 67% with infectious complications, 21% with noninfectious, and 40% without complications (P = 0.000). Multiple regression analysis identified unacceptable pain (numeric rating scale ≥6) on POD2 as a significant predictor for 30-day infectious complications (odds ratio 6.09, P = 0.001). Results confirm the association between early postoperative pain and 30-day infectious complications in a separate, homogenous surgical population. Further clinical trials should focus on finetuning of postoperative analgesia to elucidate the effects on the endocrine and immune response, preserve immune homeostasis, and prevent postoperative infectious complications.

Wound infiltration of dexmedetomidine as an adjunct to local anesthesia in postoperative analgesia for lumbar surgery: a systematic review and meta-analysis

INTRODUCTION

The vast majority of patients undergoing lumbar surgery experience varying degrees of incision pain, leading to prolonged postoperative recovery and poor satisfaction with treatment. The objective of this meta-analysis was to evaluate the efficacy and safety of dexmedetomidine as an adjunct to local anesthesia for postoperative pain control after lumbar surgery.

EVIDENCE ACQUISITION

Two authors independently searched eligible random controlled trials in electronic databases, including PubMed, Embase, Cochrane Library, Web of Science, CNKI (China National Knowledge Infrastructure), CBM (The Chinese BioMedical database) using the search terms 'dexmedetomidine', 'infiltration', and 'lumbar'. The random-effect model was used to perform the meta-analysis based on deviance information criteria.

EVIDENCE SYNTHESIS

Six trials evaluating a total of 330 patients were included in this review. Wound infiltration with dexmedetomidine significantly reduced the postoperative VAS scores (4th hour static VAS scores (MD=-1.03; 95% CI: -1.58 to -0.47; p=0.0003); 24th hour static VAS scores (MD=-0.66; 95% CI: -0.91 to -0.40; p<0.00001); 6th hour dynamic VAS scores (MD=-1.84; 95% CI: -2.23 to -1.45; p<0.00001)) and total supplemental analgesic consumption (SMD=-2.01; 95% CI: -3.04 to -0.98; p<0.00001), prolonged the median time to first rescue analgesia (SMD=3.53; 95% CI:2.31 to 4.76; p<0.00001), and reduced the incidence of nausea or vomiting (RR=0.40; 95% CI: 0.17 to 0.93; P<0.05).

CONCLUSIONS

Dexmedetomidine infiltration appears to be a promising and safe adjunct for postoperative pain control after lumbar surgery. However, more studies are needed to assess the prevalence of other side effects.

Nalbuphine Versus Ketorolac as an Adjuvant to Local Wound Infiltration Anesthesia in Open Colorectal Surgery: A Prospective Randomized Controlled Study

INTRODUCTION

Adding adjuvants to local wound infiltration (LWI) provides long analgesic duration with fewer adverse effects. We aimed to compare the clinical effects of nalbuphine and ketorolac as an adjuvant to LWI in patients undergoing open colorectal cancer surgery.

METHOD

A total of 126 ASA I-III patients aged ≥ 18 years who were scheduled for open colorectal cancer surgery were included. Patients were randomly assigned to receive LWI using 10 mL 0.75% ropivacaine, with 20 mL normal saline (group R), 10 mg nalbuphine in 1 mL (group RN), or 25 mg ketorolac in 0.8 mL (group RK). Analgesia duration was the primary outcome. The total 48-h postoperative morphine-equivalent consumption and additional rescue analgesia rates were recorded as key secondary outcomes.

RESULTS

Among 126 patients randomized, 124 completed the trial. The duration until the first press of the analgesia pump was significantly shorter in group R (median: 320.0 min) compared with group RN (median: 829.5 min) and group RK (median: 820.0 min) (P < 0.001). The median difference in morphine consumption was 113.0 mg for group R vs. group RN (P < 0.001), and 115.5 mg for group R vs. group RK (P < 0.001). The proportion of patients using additional morphine within the first day after surgery in group R showed a higher relative risk (RR) compared with group RN (RR, 3.89; P = 0.001) and group RK (RR, 3.17; P = 0.001). There were no apparent differences between the RN and RK groups in any outcomes, whether in adjusted or unadjusted analysis.

CONCLUSIONS

Among patients undergoing open colorectal cancer surgery, both nalbuphine and ketorolac infiltration achieved equally prolonged duration of analgesia and reduced morphine consumption compared with ropivacaine alone after surgery, suggesting that the equivalent analgesic dose of nalbuphine and ketorolac as local anesthetic adjuvants in LWI could have a similar analgesic effect.

TRIAL REGISTRATION

ChiCTR1800019209.

Efficacy and safety of dexmedetomidine as an adjuvant to local wound infiltration anaesthesia: A meta-analysis with trial sequential analysis of 23 randomised controlled trials

To further identify the real efficacy and safety of dexmedetomidine as an adjuvant to local wound infiltration anaesthesia, we conducted this meta‐analysis. The systematic search strategy was performed using PubMed, Embase, Cochrane Library, and Chinese databases. As a result, a total of 23 RCTs (1445 patients) were included. Patients receiving dexmedetomidine combined with local anaesthetics had a lower rescue analgesia rate [risk ratio (RR): 0.48; 95% confidence interval (CI): 0.36‐0.65] and lower rescue analgesic consumption [weighted mean difference (WMD): −10.80 mg; 95%CI: −13.28 to −8.31 mg] than patients receiving local anaesthetics alone. The dexmedetomidine‐related adverse reactions included bradycardia (RR: 1.33; 95%CI: 0.32‐5.56) and hypotension (RR: 3.00; 95%CI: 0.49‐18.42). In addition, the time to first analgesic request (WMD: 296.16 minutes; 95%CI: 165.69 minutes ~ 426.63 minutes), incidence of postoperative nausea and vomiting (PONV) and pain scores at 4 hours postoperatively were also significantly lower in patients receiving dexmedetomidine combined with local anaesthetics. This meta‐analysis demonstrated that the use of dexmedetomidine as an adjuvant to wound infiltration is effective for reducing the rescue analgesia rate, rescue analgesic consumption and PONV. In addition, limited evidence shows that dexmedetomidine can prolong postoperative analgesia for approximately 5 hours. Further investigations on dexmedetomidine‐related adverse reactions and the dose–response effect of dexmedetomidine in wound infiltration are warranted.

Adjuncts to local anesthetic wound infiltration for postoperative analgesia: a systematic review

Local anesthetics (LAs) are commonly infiltrated into surgical wounds for postsurgical analgesia. While many adjuncts to LA agents have been studied, it is unclear which adjuncts are most effective for co-infiltration to improve and prolong analgesia. We performed a systematic review on adjuncts (excluding epinephrine) to local infiltrative anesthesia to determine their analgesic efficacy and opioid-sparing properties. Multiple databases were searched up to December 2019 for randomized controlled trials (RCTs) and two reviewers independently performed title/abstract screening and full-text review. Inclusion criteria were (1) adult surgical patients and (2) adjunct and LA agents infiltration into the surgical wound or subcutaneous tissue for postoperative analgesia. To focus on wound infiltration, studies on intra-articular, peri-tonsillar, or fascial plane infiltration were excluded. The primary outcome was reduction in postoperative opioid requirement. Secondary outcomes were time-to-first analgesic use, postoperative pain score, and any reported adverse effects. We screened 6670 citations, reviewed 126 full-text articles, and included 89 RCTs. Adjuncts included opioids, non-steroidal anti-inflammatory drugs, steroids, alpha-2 agonists, ketamine, magnesium, neosaxitoxin, and methylene blue. Alpha-2 agonists have the most evidence to support their use as adjuncts to LA infiltration. Fentanyl, ketorolac, dexamethasone, magnesium and several other agents show potential as adjuncts but require more evidence. Most studies support the safety of these agents. Our findings suggest benefits of several adjuncts to local infiltrative anesthesia for postoperative analgesia. Further well-powered RCTs are needed to compare various infiltration regimens and agents.

Protocol registration

PROSPERO (CRD42018103851) (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=103851)

Comparison of Adrenaline and Dexmedetomidine in Improving the Cutaneous Analgesia of Mexiletine in Response to Skin Pinpricks in Rats

BACKGROUND

Adrenaline (Adr) and dexmedetomidine (Dex) are commonly used adjuvants of local anesthetics; however, the difference in the improvement of analgesia of local anesthetics between the 2 adjuvants remains unclear.

OBJECTIVE

The objective of this experimental research was to evaluate the cutaneous analgesic effect of mexiletine (Mex) by coadministration with Dex or Adr.

METHODS

The effect of a nociceptive block was assessed based on the inhibition of the cutaneous trunci muscle reflex in response to skin pinpricks in rats. The analgesic activity of Mex alone and Mex coadministered with Dex or Adr was evaluated after subcutaneous injections. Subcutaneous injections of drugs or combinations include Mex 0.6, 1.8, and 6.0 μmol; Adr 13.66 nmol; Dex 1.05600 nmol; saline; and Mex 1.8 and 6.0 μmol, respectively, combined with Dex 0.01056, 0.10560, and 1.05600 nmol or Adr 0.55, 2.73, and 13.66 nmol, with each injection dose of 0.6 mL.

RESULTS

Subcutaneous injections of Mex elicited dose-related cutaneous analgesia. Compared with Mex (1.8 μmol), adding Dex or Adr to Mex (1.8 μmol) solutions for skin nociceptive block potentiated and prolonged the action. Mex (6.0 μmol) combined with Dex or Adr extended the duration of cutaneous analgesia when compared with Mex (6.0 μmol) alone. A high dose of Adr is more effective with Mex 1.8 μmol than that of Dex, whereas medium and low doses were less effective. Mex 6.0 μmol combined with any dose of Adr is superior to that of Dex.

CONCLUSIONS

Both Dex and Adr improve the sensory block and enhance the nociceptive block duration of Mex. But in most cases, Adr is superior to Dex. It may be that different mechanisms of action of the 2 adjuvants lead to the differences.

Inhibition of Fast Nerve Conduction Produced by Analgesics and Analgesic Adjuvants-Possible Involvement in Pain Alleviation

Nociceptive information is transmitted from the periphery to the cerebral cortex mainly by action potential (AP) conduction in nerve fibers and chemical transmission at synapses. Although this nociceptive transmission is largely inhibited at synapses by analgesics and their adjuvants, it is possible that the antinociceptive drugs inhibit nerve AP conduction, contributing to their antinociceptive effects. Many of the drugs are reported to inhibit the nerve conduction of AP and voltage-gated Na⁺ and K⁺ channels involved in its production. Compound action potential (CAP) is a useful measure to know whether drugs act on nerve AP conduction. Clinically-used analgesics and analgesic adjuvants (opioids, non-steroidal anti-inflammatory drugs, ₂-adrenoceptor agonists, antiepileptics, antidepressants and local anesthetics) were found to inhibit fast-conducting CAPs recorded from the frog sciatic nerve by using the air-gap method. Similar actions were produced by antinociceptive plant-derived chemicals. Their inhibitory actions depended on the concentrations and chemical structures of the drugs. This review article will mention the inhibitory actions of the antinociceptive compounds on CAPs in frog and mammalian peripheral (particularly, sciatic) nerves and on voltage-gated Na⁺ and K⁺ channels involved in AP production. Nerve AP conduction inhibition produced by analgesics and analgesic adjuvants is suggested to contribute to at least a part of their antinociceptive effects.

The Effect of Dexmedetomidine Added to Preemptive Ropivacaine Infiltration on Postoperative Pain After Lumbar Fusion Surgery: A Randomized Controlled Trial

STUDY DESIGN

A prospective and controlled study of dexmedetomidine added to preemptive ropivacaine infiltration in lumbar fusion surgery.

OBJECTIVE

Assessment of dexmedetomidine added to preemptive ropivacaine infiltration for the relief of postoperative pain after lumbar fusion surgery.

SUMMARY OF BACKGROUND DATA

Single local anesthetic preemptive wound infiltration for the relief of postoperative pain does not translate into major or consistent clinical benefits after lumbar fusion surgery. Dexmedetomidine added to local anesthetics prolonged the duration of blockade and enhanced the analgesic in peripheral nerve block. The effect of dexmedetomidine added to preemptive ropivacaine infiltration in lumbar fusion surgery for the relief of postoperative pain has yet not been studied.

METHODS

Fifty-seven patients with elective posterior lumbar fusion were randomly divided into two groups. Five minutes before incision, the skin and subcutaneous tissues were injected with 20 mL 0.5% ropivacaine in group R (n = 28) and 20 mL 0.5% ropivacaine and 1 ug/kg of dexmedetomidine in group RD (n = 29) in two divided doses (i.e., 10 mL per side of the incision line). After the operation, all patients received intravenous morphine for analgesia. The total morphine consumption, the time of first analgesic demand, numbers of PCA analgesia, Visual Analog Scale, and postoperative adverse effects were collected.

RESULTS

In group RD, cumulative morphine dose and numbers of PCA analgesia in group RD were significantly reduced, the time of first analgesic demand was significantly delayed compared to the group R. Visual Analog Scale in group RD showed a marked reduction at 8 hours, 12 hours, 16 hours after operation and less patients in group RD experienced postoperative nausea or vomiting compared to the group R.

CONCLUSION

The addition of dexmedetomidine to preemptive ropivacaine wound infiltration provided a superior analgesic effect, reduced postoperative morphine consumption, and prolonged the time of the first analgesic demand with no serious side effects.

LEVEL OF EVIDENCE

2.

Efficacy of dexmedetomidine as an adjuvant to local wound infiltration anaesthesia in abdominal surgery: A meta-analysis of randomised controlled trials

To assess the efficacy and safety of dexmedetomidine (DEX) as an adjuvant to local wound infiltration anaesthesia in abdominal surgery, we conducted this meta-analysis. First, the systematic search strategy was performed on PubMed, Embase, and Cochrane Library and five randomised controlled trials (RCTs) involving 294 patients were included. Then, the outcome data were extracted from the studies and their effect sizes were calculated using Review Manager 5. As a result, the addition of DEX significantly reduced visual analogy scores at 6 hours after surgery (mean difference = -0.53[-0.82, -0.25], P < .001), 12 hours after surgery (mean difference = -0.39 [-0.73, -0.05]; P = .03), and 24 hours after surgery (mean difference = -0.20 [-0.29, -0.11], P < .001) and reduced total analgesic consumption within 24 hours after surgery (mean difference = -4.92 [-9.00, -0.84]; P = .02) compared with placebo groups. However, there was no difference in the incidence of postoperative nausea and vomiting (risk ratio = 0.68 [0.41, 1.14]; P = .14). In summary, DEX as a local anaesthetic adjuvant added for local wound infiltration anaesthesia in abdominal surgery could reduce visual analogy scores and postoperative analgesic consumption without changing incidence of postoperative nausea and vomiting.

Opioid Use in the Postoperative Arena: Global Reduction in Opioids After Surgery Through Enhanced Recovery and Gynecologic Surgery

Enhanced recovery programs aim to reduce surgical stress to improve the patient perioperative experience. Through a combination of multimodal analgesia and maintaining a physiological state, postoperative recovery is improved. Many analgesic adjuncts are available that improve postoperative pain control and limit opioid analgesia requirements. Adjuncts are often used in combination, but different interventions may be incorporated for patient-specific and procedure-specific needs. Postoperative pain control can be optimized by continuing nonopioid adjuncts, and prescribing opioid analgesia to address breakthrough pain. Prescribing practices should balance optimizing pain relief, minimizing the risk of chronic pain, while limiting the potential for opioid misuse.