Protective effects of dexmedetomidine combined with flurbiprofen axetil on remifentanil-induced hyperalgesia: A randomized controlled trial

Effects of an intraoperative intravenous Bolus Dose of Dexmedetomidine on postoperative catheter-related bladder discomfort in male patients undergoing transurethral resection of bladder tumors: a randomized, double-blind, controlled trial

PURPOSE

To investigate whether the effect of intravenous bolus doses of dexmedetomidine on postoperative catheter-related bladder discomfort (CRBD) was dose-dependent in male patients undergoing transurethral resection of bladder tumors (TURBT).

METHODS

The study protocol was registered at the Chinese Clinical Trial Registry (ChiCTR 2,000,034,657, date of registration: July 14, 2020). Adult male patients were randomized to one of four groups: placebo (Group C); dexmedetomidine 0.2 µg/kg (Group D 0.2); dexmedetomidine 0.5 µg/kg (Group D 0.5); or dexmedetomidine 1 µg/kg (Group D 1). The primary outcome was the incidence of moderate-to-severe CRBD at 0, 1, 6, 24, and 48 h postoperatively.

RESULTS

The incidence of moderate-to-severe CRBD was significantly lower in Group D 0.5 and Group D 1 than in Group C at 0 h (13% vs. 40%, P = 0.006; 8% vs. 40%, P = 0.001), 1 h (15% vs. 53%, P < 0.001; 13% vs. 53%, P < 0.001), and 6 h (10% vs. 32%, P = 0.025; 8% vs. 32%, P = 0.009) postoperatively. Compared with baseline, both the MAP and HR were significantly lower in Group D 1 at 1 min ([94 ± 15] vs. [104 ± 13] mm Hg, P = 0.003; [64 ± 13] vs. [73 ± 13] bpm, P = 0.001) and 30 min ([93 ± 10] vs. [104 ± 13] mm Hg, P < 0.001; [58 ± 9] vs. [73 ± 13] bpm, P < 0.001) postextubation.

CONCLUSION

The effect of intravenous bolus doses of dexmedetomidine on postoperative CRBD was dose-independent, whereas intravenous administration of 0.5 µg/kg dexmedetomidine reduced the early postoperative incidence of CRBD with minimal side effects.

TRIAL REGISTRATION

Clinical trial number and registry URL: ChiCTR 2,000,034,657, http://www.chictr.org.cn , date of registration: July 14, 2020.

New Perspective for Drug-Drug Interaction in Perioperative Period

In this review, we aim to discuss current information on drug interactions in the perioperative period. During this period, patients receive several drugs that may interact with each other and affect the efficacy and safety of the treatment. There are three types of drug interactions: pharmacodynamic, pharmacokinetic, and pharmaceutical. It is important to recognize that drug interactions may increase the toxicity of the drug or reduce its efficacy, increasing the risk of complications in the perioperative period. This review describes the most commonly used perioperative drugs approved by the FDA and some of the described interactions between them. Thoroughly reviewing a patient's medication list and identifying potential interactions are essential steps in minimizing risks. Additionally, vigilant monitoring of patients during and after surgery plays a pivotal role in early detection of any signs of drug interactions. This article emphasizes the significance of addressing DDIs in the perioperative period to ensure patient well-being and advocates for the implementation of careful monitoring protocols to promptly identify and manage potential interactions.

Efficacy and safety of intravenous dexmedetomidine as an adjuvant to general anesthesia in gynecological surgeries: A systematic review and meta-analysis of randomized controlled trials

This study investigated the efficacy and safety of intravenous dexmedetomidine as an adjuvant to general anesthesia in patients undergoing gynecological surgery. We systemically searched for randomized controlled trials (RCTs), and performed a meta-analysis on studies that met the inclusion criteria. The primary outcomes were postoperative nausea and vomiting (PONV), bradycardia, hypotension, and 24 h opioid consumption. The secondary outcomes include postoperative shivering, postoperative pain score, intraoperative anesthetic consumption, extubation time, postoperative sedation, and the time to first flatus. Twenty-five RCTs were included in this study. Meta-analysis showed that intravenous dexmedetomidine significantly reduced the risk of PONV (RR, 0.57 [0.47, 0.68]) and postoperative shivering (RR: 0.31 [0.22, 0.42]), 24 h opioid consumption (Mean Difference: - 4.85 mg [-8.60, -1.11]) and postoperative pain score within 24 h. However, these benefits were at the cost of increased bradycardia (RR, 3.21 [2.41, 4.28]) and hypotension (RR, 2.17 [1.50, 3.14]). Notably, no serious adverse effects were reported in any of the included studies. Thus, our study showed that intravenous dexmedetomidine provided significant antiemetic and anti-shivering effects and moderate analgesic effects in patients that underwent gynecological surgery. However, its benefits should be weighed against the significantly increased risk of bradycardia and hypotension.

Changes of Entropy Index and Cerebral Oxygen Metabolism in the Maintenance of Remifentanil Anesthesia and Their Predictive Value for Postoperative Hyperalgesia

Objective

To explore the changes of entropy index and cerebral oxygen metabolism in the maintenance of remifentanil anesthesia and the predictive value of postoperative hyperalgesia.

Methods

A total of 266 patients undergoing general anesthesia in our hospital from January 2020 to October 2021 were selected, and remifentanil was used to maintain anesthesia. The state entropy, reaction entropy, and cerebral oxygen metabolism indexes (cerebral oxygen uptake rate (CERO₂), arterial-venous blood oxygen difference (Da-jvO₂)) of patients before induction of anesthesia, 15 minutes during the operation, and at the end of the operation were compared. The influencing factors of postoperative hyperalgesia were analyzed. The logistic regression model of postoperative hyperalgesia was established, and the value of entropy index and cerebral oxygen metabolism in predicting postoperative hyperalgesia was evaluated by drawing the receiver operating characteristic curve (ROC).

Results

The state entropy, response entropy, and CERO₂ at 30 min during the operation and at the end of the operation were lower than those before the induction of anesthesia, and Da-jvO₂ was higher than that before the induction of anesthesia (P < 0.001). At the end of the operation, the state entropy, reaction entropy, and CERO₂ were higher than 30 minutes during the operation, and Da-jvO₂ was lower than 30 minutes during the operation (P < 0.001). The dosage of remifentanil, reaction entropy, and CERO₂ at the end of the operation entered the logistic model. The AUC value of the reaction entropy and CERO₂ combined to predict postoperative hyperalgesia at the end of the operation was 0.851 greater than the reaction entropy at the end of the operation (χ² = 3.847, P = 0.036), CERO₂ (χ² = 2.589, P = 0.010) single index predictive value.

Conclusion

The entropy index and cerebral oxygen metabolism in general anesthesia patients change with the progress and discontinuation of remifentanil maintenance anesthesia, and the combination of the two has a high predictive power in postoperative hyperalgesia risk assessment. When the reaction entropy > 54.23, CERO₂ > 34.14%, or the total dosage of remifentanil ≥ 30 μg/kg at the end of the operation, we should be highly vigilant of the occurrence of postoperative hyperalgesia and postoperative analgesia management should be strengthened.

Opioid-induced Hyperalgesia in Patients With Chronic Pain: A Systematic Review of Published Cases

INTRODUCTION

Opioid-induced hyperalgesia (OIH) remains an issue in patients with chronic pain. Multiple cases of OIH in patients with chronic pain exposed to opioids have been reported worldwide. The objective of this systematic review was to summarize the evidence of OIH from clinical reports.

METHODS

We searched the PubMed, Cochrane, EMBASE, and LILACS databases for case reports and case series of OIH published up to December 2020, with the aim to summarize the evidence for OIH in patients with chronic pain from clinical reports and to discuss issues relevant to the clinical diagnosis and management of OIH.

RESULTS

We retrieved and reviewed 41 articles describing 72 cases. Clinical features of OIH were observed in patients of both sexes, all ages, and with various types of pain treated with different classes of opioids. OIH was reported at all doses, but most published studies reported a pattern of OIH following treatment with very high daily doses of opioids (median oral morphine equivalent dose of 850 mg). OIH was diagnosed clinically in all cases. Three different strategies for OIH management were described: opioid rotation, opioid cessation, and the use of adjuvant pharmacotherapies. All had statistically similar success rates for OIH treatment: 72%, 57%, and 79%, respectively. The decrease in pain was achieved rapidly (mean: 8 d; range: 1 to 28 d). Adjuvant therapies resulted in the largest decrease in dose. Ketamine and dexmedetomidine were the most widely used adjuvant drugs.

CONCLUSION

The key finding is that clinical symptoms of OIH can be resolved when this condition is diagnosed and managed.

Postoperative Drip-Infusion of Remifentanil Reduces Postoperative Pain-A Retrospective Observative Study

Development of remifentanil-induced hyperalgesia (RIH) postoperatively is an unpleasant experience that requires further treatment. This study assessed the effects of gradual withdrawal combined with drip infusion of remifentanil on postoperative pain and the requirement for rescue analgesics. A total of 559 patients receiving total intravenous anesthesia with propofol and remifentanil were enrolled. All patients either underwent gradual withdrawal of remifentanil (GWR) or gradual withdrawal combined with drip infusion (GWDR) with a dose of 1 mcg·kg⁻¹ for 30 min after extubation. The numeric rating scale (NRS) and the requirement of rescue analgesics were assessed. The requirement for rescue analgesics was significantly lower in the GWDR group than in the GWR group (13.2% vs. 35.7%; p < 0.001). At the post-anesthetic care unit (PACU), patients in the GWDR group had a lower NRS pain score (p < 0.001). In addition, in the postoperative 2nd hour, patients in the GWDR group had a significantly lower NRS than the GWR group (beta, −0.31; p = 0.003). No remifentanil-related adverse effects were observed. We found that gradual withdrawal combined with drip infusion of remifentanil required less rescue analgesics and reduced pain scores. The new way of remifentanil administration may be effective to prevent RIH.

Effects of an Intraoperative Intravenous Bolus Dose of Dexmedetomidine on Remifentanil-Induced Postinfusion Hyperalgesia in Patients Undergoing Thyroidectomy: A Double-Blind Randomized Controlled Trial

BACKGROUND

Consecutive exposure to high-dose remifentanil during anesthesia may induce remifentanil-induced postinfusion hyperalgesia (RPH). Dexmedetomidine, a highly selective α2-adrenergic receptor agonist, may have synergistic effects with opioids and aid in perioperative pain management. In this study, we hypothesized that an intraoperative bolus dose of intravenous dexmedetomidine could alleviate RPH in patients undergoing thyroidectomy under general anesthesia.

METHODS

Ninety patients undergoing thyroidectomy were randomly assigned to 1 of 3 groups: placebo, normal saline (group P); low-dose dexmedetomidine 0.2 μg·kg-1 (group LD); or high-dose dexmedetomidine 0.5 μg·kg-1 (group HD). Remifentanil was infused at a rate of 0.30 μg·kg-1·minute-1. Mechanical pain thresholds were measured using an Electronic von Frey device preoperatively and at 30 minutes, 6 hours, 24 hours, and 48 hours after surgery and were analyzed with 2-way repeated-measures analysis of variance (ANOVA) followed by Bonferroni post hoc comparison. We also recorded postoperative pain scores, the incidence of receiving rescue analgesics, and side effects up to 48 hours after surgery.

RESULTS

The mechanical pain thresholds around the skin incision were significantly higher in group LD compared to group P 30 minutes and 6 hours after surgery (mean ± standard deviation: [65.0 ± 25.2] vs [49.6 ± 24.4] g, mean difference [95% confidence interval]: 15.4 [0.3-30.5] g, P = .045 at 30 minutes; [65.9 ± 24.5] vs [49.3 ± 26.1] g, 16.6 [1.1-32.1] g, P = .032 at 6 hours). The pain thresholds around the skin incision were significantly higher in group HD compared to group P 30 minutes and 6 hours after surgery ([67.8 ± 21.7] vs [49.6 ± 24.4] g, 18.2 [3.1-33.3] g, P = .013 at 30 minutes; [68.3 ± 22.5] vs [49.3 ± 26.1] g, 19.0 [3.5-34.5] g, P = .011 at 6 hours). The incidence of hyperalgesia around the skin incision was lower in group HD than in group P 30 minutes and 6 hours after surgery (4 [13%] vs 14 [48%], P = .012 at 30 minutes, 4 [13%] vs 12 [41%], P = .045 at 6 hours), although no significant difference was observed between group LD and group P. Postoperative pain scores, the incidence of rescue analgesic demand, and postoperative side effects were not significantly different between the groups.

CONCLUSIONS

An intraoperative intravenous bolus dose of dexmedetomidine 0.5 μg·kg-1 alleviates remifentanil-induced hyperalgesia in patients undergoing thyroidectomy without a significant difference in side effects.

Efficacy of Flurbiprofen for Postoperative Pain in Chinese Surgical Patients: A Meta-Analysis

BACKGROUND

The objective of this meta-analysis is to assess the analgesic effect of flurbiprofen on postoperative pain in Chinese surgical patients.

METHODS

The primary outcome was acute postoperative pain scores; the secondary outcomes included total opiate consumption during surgery and adverse effects, such as nausea, vomiting, and dizziness. Results were expressed as weighted mean difference (WMD) or odds ratio with 95% confidence intervals (95% CIs). We evaluated heterogeneity by visually examining the forest plots and quantified it by using the I² statistic. We used random-effects models to pool the data.

RESULTS

Of 573 abstracts reviewed, 19 studies involving 1628 participants met the inclusion criteria. Pooled results showed that the intravenous administration of flurbiprofen had a beneficial effect in reducing pain scores at 2 (WMD, -0.78; 95% CI, -1.22 to -0.34; P = 0.001), 6 (WMD, -0.93; 95% CI, -1.40 to -0.46; P = 0.000), 12 (WMD, -1.09; 95% CI, -1.93 to -0.24; P = 0.011), 24 (WMD, -1.08; 95% CI, -1.48 to -0.68; P = 0.000), and 48 (WMD, -0.62; 95% CI, -1.19 to -0.05; P = 0.032) h after surgery. In addition, flurbiprofen administration significantly decreased the incidence of postoperative nausea and vomiting (odds ratio, 0.39; 95% CI, 0.26-0.58; P = 0.000) but had no effects on opiate consumption and dizziness.

CONCLUSIONS

The perioperative administration of flurbiprofen is effective in reducing postoperative pain, nausea, and vomiting in Chinese surgical patients. Future studies with adequate power should evaluate the ideal flurbiprofen regimen for postoperative pain.

Effect of ultrasound-guided peripheral nerve blocks of the abdominal wall on pain relief after laparoscopic cholecystectomy

Purpose: The aim of this study was to compare the effect of an ultrasound-guided transversus abdominis plane block (TAPB) and rectus sheath block (RSB) combination, an ultrasound-guided posterior TAP block combined with the local anesthetic infiltration (LAI) and LAI alone on pain relief after laparoscopic cholecystectomy (LC). Patients and methods: One hundred eighty patients who were American Society of Anesthesiologists class Ι or Π were included in this randomized, double-blind, non-inferiority study. All patients underwent three-port LC and were divided into 3 groups. The LAI group had ropivacaine mixed with dexmedetomidine injected around the trocar entrance site preoperatively. The TL group underwent ultrasound-guided posterior TAPB combined with LAI, and the TR group underwent ultrasound-guided TAPB combined with RSB. Postoperative pain was evaluated at the first, 4th, 8th, 24th, and 48th hours. If the visual analogue scale (VAS) score (including incisional pain, visceral pain or shoulder pain) was >3, intravenous dezocine (0.05 mg/kg) was injected slowly. Sleep quality, total consumption of dezocine and time to unassisted walking were recorded. The Global Satisfaction Score (GSS) for analgesia was also assessed within 48 hrs. Results: No difference was found in sleep quality, time to unassisted walking, or requirement for dezocine. We also found no difference in VAS scores at each time point within 48 hrs after LC among the 3 groups, but the GSS for analgesia in the LAI group was significantly increased within 48 hrs compared with the other two groups. Conclusion: Ultrasound-guided peripheral nerve blocks of the abdominal wall can significantly relieve postoperative pain in patients undergoing LC; however, patients receiving LAI expressed more satisfaction than patients in whom other methods were used. LAI is an easy and effective method that can be recommended for routine clinical practice in LC patients who are not converted to an open procedure.

The influence of dexmedetomidine on remifentanil-induced hyperalgesia and the sex differences

In the clinical settings, patients often develop opioid-induced hyperalgesia (OIH) after utilization of high dose intra-operative remifentanil. Systemic α2 agonists, including dexmedetomidine, are believed to reduce pain and opioid requirements after surgery, thus decreasing the incidence of hyperalgesia. The present study aimed to investigate the effect of dexmedetomidine on remifentanil-induced hyperalgesia and explored the sex differences. A total of 48 patients (24 male, 24 female) with an American Society of Anesthesiologists physical status of I-II that were undergoing thyroidectomy were randomly assigned to one of the following six groups: Male controlled group (MC) and female controlled group (FC) (group MC, n=8 and group FC, n=8), which received a preoperative placebo of 0.2 µg.kg^-1 normal saline and intraoperative remifentanil 0.2 µg.kg^-1.min^-1; male and female group with low-dose dexmedetomidine (group MD1, n=8 and group FD1, n=8), which received preoperative dexmedetomidine 0.2 µg.kg^-1 and intraoperative remifentanil 0.2 µg.kg^-1.min^-1; and male and female groups with high-dose dexmedetomidine (group MD2, n=8 and group FD2, n=8), which received dexmedetomidine 0.6 µg.kg^-1 and intraoperative remifentanil 0.2 µg.kg^-1.min^-1. Result indicated that the visual analog scale (VAS) scores and morphine dosing frequency were significantly higher in MC and FC groups compared with the other same sex groups. Furthermore, the mechanical hyperalgesia threshold and patients' analgesia satisfaction score after surgery were significantly lower in MC and FC groups. Notably, the frequency of post-operative chills, nausea and vomiting were significantly lower in groups MD1, MD2, FD1 and FD2. The present findings indicated that low- and high-dose dexmedetomidine injection significantly decreased the patient's risk of enhanced pain intensity and increased postoperative morphine dosing caused by remifentanil-induced hyperalgesia. These findings suggest that the influence of dexmedetomidine displayed minimal significant differences between sex. Trial registration no., IRB2018-YX-001 (Name of registry: Institutional Medical Ethics Committee of Tianjin Medical University General Hospital; date of registration: February 1, 2016).