Perioperative Opioid Administration

Is General Anesthesia for Peripheral Vascular Surgery Correlated with Impaired Outcome in Patients with Cardiac Comorbidity? A Closer Look into the Nationwide Danish Cohort

OBJECTIVE

General anesthesia (GA) may impair outcome after vascular surgery. The use of anticoagulant medication is often used in patients with cardiac comorbidity. Regional anesthesia (RA) requires planning of discontinuation before neuraxial blockade(s) in this subgroup. This study aimed to describe the effect of anesthesia choice on outcome after vascular surgery in patients with known cardiac comorbidity.

DESIGN

Retrospective cohort study.

SETTING

Danish hospitals.

PARTICIPANTS

6302 patients with known cardiac comorbidity, defined as ischemic heart disease, valve disease, pulmonary vascular disease, heart failure, and cardiac arrhythmias, undergoing lower extremity vascular surgery between 2005 and 2017.

INTERVENTIONS

GA versus RA.

MEASUREMENTS AND MAIN RESULTS

Data were extracted from national registries. GA was defined as anesthesia with mechanical ventilation. Multivariable regression models were used to describe the incidence of postoperative complications as well as 30-day mortality, hypothesizing that better outcomes would be seen after RA. The rate of RA decreased from 48% in 2005 to 20% in 2017. The number of patients with 1 or more complications was 9.7% vs 6.2% (p < 0.001), and 30-day mortality was 6.0% vs 3.4% (p < 0.001) after GA. After adjusting for baseline differences, the odds ratio (OR) was significantly lower for medical complications (cardiac, pulmonary, renal, new dialysis, intensive care unit and other medical complications; OR, 0.97; 95% confidence interval [CI], 0.95-0.98) and 30-day mortality (OR 0.98; 95% CI, 0.97-0.99) after RA.

CONCLUSIONS

RA may be associated with a better outcome than GA after lower extremity vascular surgery in patients with a cardiac comorbidity. Prioritizing RA, despite the inconvenience of discontinuing anticoagulants, may be recommended.

Opioid-free general anesthesia: considerations, techniques, and limitations

PURPOSE OF REVIEW

To discuss the role of opioids during general anesthesia and examine their advantages and risks in the context of clinical practice. We define opioid-free anesthesia (OFA) as the absolute avoidance of intraoperative opioids.

RECENT FINDINGS

In most minimally invasive and short-duration procedures, nonopioid analgesics, analgesic adjuvants, and local/regional analgesia can significantly spare the amount of intraoperative opioid needed. OFA should be considered in the context of tailoring to a specific patient and procedure, not as a universal approach. Strategies considered for OFA involve several adjuncts with low therapeutic range, requiring continuous infusions and resources, with potential for delayed recovery or other side effects, including increased short-term and long-term pain. No evidence indicates that OFA leads to decreased long-term opioid-related harms.

SUMMARY

Complete avoidance of intraoperative opioids remains questionable, as it does not necessarily ensure avoidance of postoperative opioids. Multimodal analgesia including local/regional anesthesia may allow OFA for selected, minimally invasive surgeries, but further research is necessary in surgeries with high postoperative opioid requirements. Until there is definitive evidence regarding procedure and patient-specific combinations as well as the dose and duration of administration of adjunct agents, it is imperative to practice opioid-sparing approach in the intraoperative period.

The effect of preemptive retrolaminar block on lumbar spinal decompression surgery

PURPOSE

Spinal decompression surgery causes severe pain. Retrolaminar block (RLB) is block, which is done by infiltration of local anesthetic to block spinal nerves between the lamina and superior costotransversospinalis muscle. The primary aim of this study is to evaluate the effectiveness of RLB on postoperative analgesia in patients undergoing spinal surgery. Secondary aims are effects on additional anesthetic and analgesic consumption.

METHODS

The sixty (60) patients who underwent lumbar spinal surgery between May 2020 and May 2021 under general anesthesia with or without applied preemptive RLB for postoperative analgesia were included in this prospective observational study. Group I received ultrasound-guided preemptive RLB. In Group II, no intervention was performed. Postoperative VAS scores were compared in groups as primary outcome, perioperative additional anesthetic and analgesic needs were compared as secondary outcome.

RESULTS

There was a significant difference between the groups in favor of the RLB group in terms of postoperative VAS scores at rest [1.33 (0.33-3.509)] and movement [2.40 (1.20-4.00)] (p < 0.001). Perioperative sevoflurane consumption was significantly low in block group (p < 0.001). Postoperative tramadol consumption was lower in Group I compared with Group II [Group 1: 200 (100-300); Group 2: 37.5 (0-200); p < 0.001].

CONCLUSION

Preemptive RLB may be used to reduce patients' pain in lumbar decompression surgery as well as to be part of a multimodal analgesia and anesthesia regimen to reduce anesthetic and analgesic drug consumption. Trial registration numberClinicalTrials.gov (No. NCT04209907).

Intravenous ibuprofen versus ketorolac for perioperative pain control in open abdominal hysterectomy: a randomized controlled trial

BACKGROUND

We aimed to compare the analgesic effects of intravenous ibuprofen to ketorolac after open abdominal hysterectomy.

METHODS

This randomized double-blinded controlled trial included adult women scheduled for elective open abdominal hysterectomy. Participants were randomized to receive either 30 mg ketorolac (n = 50) or 800 mg ibuprofen (n = 50) preoperatively, then every 8 h postoperatively for 24 h. All participants received paracetamol 1 gm/6 h. Rescue analgesic was given if the visual analogue scale (VAS) for pain assessment was > 3. The primary outcome was the mean postoperative dynamic VAS during the first 24 h. Secondary outcomes were static VAS, intraoperative fentanyl consumption, postoperative morphine consumption, time to independent movement, and patient's satisfaction.

RESULTS

Forty-six patients in the ibuprofen group and fifty patients in the ketorolac group were analyzed. The 24-h dynamic and static VAS were similar in the two groups. The median (quartiles) dynamic VAS was 1.1 (0.9, 1.9) in the ibuprofen group versus 1.0 (0.7, 1.3) in the ketorolac group, P-value = 0.116; and the median (quartiles) static VAS was 0.9 (0.6, 1.3) in the ibuprofen group versus 0.7 (0.4, 1.1) in the ketorolac group, P-value = 0.113. The intra- and postoperative analgesic requirements were also similar in the two groups. However, patient satisfaction was slightly higher in the ketorolac group than that in the ibuprofen group (median [quartiles]: 6 [5, 7] versus 5 [4, 7], respectively), P-value: 0.009.

CONCLUSION

The two drugs, intravenous ibuprofen and ketorolac produced similar analgesic profile in patients undergoing open abdominal hysterectomy receiving multimodal analgesic regimen. NCT05610384, Date of registration: 09/11/2022 CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05610384. https://clinicaltrials.gov/ct2/show/NCT05610384.

Strong opioids-induced cardiac, neurologic, and respiratory disorders: a real-world study from 2004 to 2023 based on FAERS

Opioids are mainly used as adjuncts to the induction and maintenance of general anesthesia, postoperative analgesia, and treating moderate to severe cancer pain and chronic pain. However, the hazards of these drugs to various organ organs still need to be further explored. This study used the US FDA Adverse Event Reporting System (FAERS) database to determine whether commonly receiving opioids was higher than the baseline risk for all other medications. FAERS was asked about adverse events (AEs) for the opioids "morphine," "fentanyl," "oxycodone," "hydromorphone," "sufentanil," and "remifentanil" from the first quarter of 2004 (2004Q1) through the second quarter of 2023 (2023Q2). Disproportionality signaling analysis was performed by calculating reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and Empirical Bayesian Geometric Mean (EBGM). AEs with system organ classes (SOCs) of "cardiac disease," "neurologic disease," and "respiratory, thoracic, and mediastinal disease" were then screened. The statistical analysis included 12,819,518 reports in the FAERS database from 2004Q1 to 2023Q2, of which 236,619 AEs were reported as "primary suspect" for the six drugs mentioned above, which were selected as "cardiac disorders," "nervous system disorders," and "respiratory, thoracic and mediastinal disorders." Some AEs identified in this study are consistent with the drug labeling, such as bradycardia, respiratory depression, and somnolence. In addition, some unexpected and significant acute adverse drug reactions (ADRs), such as toxic leukoencephalopathy and coma, may occur. This study identified potential new and unexpected ADRs for opioids, providing valuable evidence for safety studies of opioids.

The Development and Implementation of the Fast-Pace Assessment Framework and Tiered Analgesic Orders for Opioid Optimization

BACKGROUND

Within the context of the opioid epidemic, changes needed to be made in the prescription and administration of analgesics. The purpose of this paper is to describe the development and implementation of a project that utilized a holistic pain assessment framework and introduced new order sets to guide the integration of nonopioid, opioid, and co-analgesics in a quaternary care medical center.

METHODS

An interdisciplinary team updated policies and procedures for pain assessment and opioid administration and created new analgesic order sets for both adult and pediatric patients. Following requisite approvals, these order sets were integrated into the electronic health record. Education of clinicians, patients, and caregivers was provided to facilitate implementation of these new clinical practices.

RESULTS

Prescribers' levels of adherence with the use of the pain order sets ranged from 80% to 90% and no adverse effects were reported. Education of nursing staff was incorporated into hospital orientation. Ongoing evaluations are providing insights into how the new policies and procedures can be optimized to ensure reliable, safe, and effective pain management.

CONCLUSIONS

Since the implementation of the opioid optimization project, adherence with the tiered, multimodal approach to analgesic prescribing is high. Next steps include both qualitative and quantitative evaluations of the benefits and challenges associated with this practice change. For example, systems will be developed to monitor nurses' adherence with the implementation of the pain order sets and the use of both pharmacologic and nonpharmacologic pain management interventions.

Balanced opioid-free anesthesia with lidocaine and esketamine versus balanced anesthesia with sufentanil for gynecological endoscopic surgery: a randomized controlled trial

In this randomized controlled trial, 74 patients scheduled for gynecological laparoscopic surgery (American Society of Anesthesiologists grade I/II) were enrolled and randomly divided into two study groups: (i) Group C (control), received sufentanil (0.3 μg/kg) and saline, followed by sufentanil (0.1 μg/kg∙h) and saline; and (ii) Group F (OFA), received esketamine (0.15 mg/kg) and lidocaine (2 mg/kg), followed by esketamine (0.1 mg/kg∙h) and lidocaine (1.5 mg/kg∙h). The primary outcome was the 48-h time-weighted average (TWA) of postoperative pain scores. Secondary outcomes included time to extubation, adverse effects, and postoperative sedation score, pain scores at different time points, analgesic consumption at 48 h, and gastrointestinal functional recovery. The 48-h TWAs of pain scores were 1.32 (0.78) (95% CI 1.06-1.58) and 1.09 (0.70) (95% CI 0.87-1.33) for Groups F and C, respectively. The estimated difference between Groups F and C was - 0.23 (95% CI - 0.58 - 0.12; P = 0.195). No differences were found in any of the secondary outcomes and no severe adverse effects were observed in either group. Balanced OFA with lidocaine and esketamine achieved similar effects to balanced anesthesia with sufentanil in patients undergoing elective gynecological laparoscopic surgery, without severe adverse effects.Clinical Trial Registration: ChiCTR2300067951, www.chictr.org.cn 01 February, 2023.

Impact of fluid balance and opioid-sparing anesthesia within enchanced recovery pathway on postoperative morbidity after transthoracic esophagectomy for cancer

Background

Enhanced Recovery After Surgery (ERAS) protocol for esophagectomy may reduce the high incidence of postoperative morbidity and mortality. The aim of this study was to assess the impact of properly conducted ERAS protocol with specific emphasis on fluid balance and opioid-sparing anesthesia (OSA) on postoperative major morbidity and mortality after esophagectomy.

Methods

Patients undergoing elective esophagectomy for esophageal cancer at the Hospital for Digestive Surgery, University Clinical Center of Serbia, from December 2017 to March 2021, were included in this retrospective observational study. Patients were divided into two groups: the ERAS group (OSA, intraoperative goal-directed therapy, and postoperative “near-zero” fluid balance) and the control group (opioid-based anesthesia, maintenance mean blood pressure ≥ 65 mmHg, and liberal postoperative fluid management). The primary outcome was major morbidity within 30 days from surgery and 30-day and 90-day mortality. Multivariable analysis was used to examine the effect of the ERAS protocol.

Results

A total of 121 patients were divided into the ERAS group (69 patients) and the control group (52 patients). Patients in the ERAS group was received less fentanyl, median 300 (interquartile range (IQR), 200–1,550) mcg than in control group, median 1,100 (IQR, 650–1750) mcg, p &lt; 0.001. Median intraoperative total infusion was lower in the ERAS group, 2000 (IQR, 1000–3,750) mL compared to control group, 3,500 (IQR, 2000–5,500) mL, p &lt; 0.001. However, intraoperative norepinephrine infusion was more administered in the ERAS group (52.2% vs. 7.7%, p &lt; 0.001). On postoperative day 1, median cumulative fluid balance was 2,215 (IQR, −150-5880) mL in the ERAS group vs. 4692.5 (IQR, 1770–10,060) mL in the control group, p = 0.002. After the implementation of the ERAS protocol, major morbidity was less frequent in the ERAS group than in the control group (18.8% vs. 75%, p &lt; 0.001). There was no statistical significant difference in 30-day and 90-day mortality (p = 0.07 and p = 0.119, respectively). The probability of postoperative major morbidity and interstitial pulmonary edema were higher in control group (OR 5.637; CI95%:1.178–10.98; p = 0.030 and OR 5.955; CI95% 1.702–9.084; p &lt; 0.001, respectively).

Conclusion

A major morbidity and interstitial pulmonary edema after esophagectomy were decreased after the implementation of the ERAS protocol, without impact on overall mortality.

Noninferiority trials in acute pain research: a valid approach or a slippery slope?

The conduct and reporting of studies with a noninferiority hypothesis is challenging because of the complexity involved in their design and interpretation. However, studies with a noninferiority design have increased in popularity. A recently published trial reported on the noninferiority of lidocaine infusion to epidural analgesia in major abdominal surgeries. Apart from needing a critical appraisal, this draws attention to improve our understanding of noninferiority study framework and its unique features. Given the increasing focus on using various analgesic adjuncts and multiple approaches to fascial plane blocks to avoid more definitive and standard approaches, it is imperative that particular attention is paid to appropriate execution and reporting of noninferiority studies.

Regional anaesthesia for postoperative pain management following laparoscopic, visceral, non-oncological surgery a systematic review and meta-analysis

BACKGROUND

Postoperative pain management following laparoscopic, non-oncological visceral surgery in adults is challenging. Regional anaesthesia could be a promising component in multimodal pain management.

METHODS

We performed a systematic review and meta-analysis with GRADE assessment. Primary outcomes were postoperative acute pain intensity at rest/during movement after 24 h, the number of patients with block-related adverse events and the number of patients with postoperative paralytic ileus.

RESULTS

82 trials were included. Peripheral regional anaesthesia combined with general anaesthesia versus general anaesthesia may result in a slight reduction of pain intensity at rest at 24 h (mean difference (MD) - 0.72 points; 95% confidence interval (CI) - 0.91 to - 0.54; I2 = 97%; low-certainty evidence), which was not clinically relevant. The evidence is very uncertain regarding the effect on pain intensity during activity at 24 h (MD -0.8 points; 95%CI - 1.17 to - 0.42; I2 = 99%; very low-certainty evidence) and on the incidence of block-related adverse events. In contrast, neuraxial regional analgesia combined with general anaesthesia (versus general anaesthesia) may reduce postoperative pain intensity at rest in a clinical relevant matter (MD - 1.19 points; 95%CI - 1.99 to - 0.39; I2 = 97%; low-certainty evidence), but the effect is uncertain during activity (MD - 1.13 points; 95%CI - 2.31 to 0.06; I2 = 95%; very low-certainty evidence). There is uncertain evidence, that neuraxial regional analgesia combined with general anaesthesia (versus general anaesthesia) increases the risk for block-related adverse events (relative risk (RR) 5.11; 95%CI 1.13 to 23.03; I2 = 0%; very low-certainty evidence).

CONCLUSION

This meta-analysis confirms that regional anaesthesia might be an important part of multimodal postoperative analgesia in laparoscopic visceral surgery, e.g. in patients at risk for severe postoperative pain, and with large differences between surgical procedures and settings. Further research is required to evaluate the use of adjuvants and the additional benefit of regional anaesthesia in ERAS programmes.

PROTOCOL REGISTRATION

PROSPERO CRD42021258281.

Management of acute postoperative pain: Conditions to guarantee the safety and effectiveness of analgesic treatments

The evidence on postoperative pain management is of low or insufficient quality. The SEDAR Acute Pain Working Group has prepared this guideline-document to apply the best available scientific evidence to clinical practice, individualizing it based on factors specific to the patient and the procedure, and encompassing different organizational options, attempting to individualize it based on specific factors of the patient and the procedure, and encompassing the different organizational options for pain control. The document updates concepts and minimum requirements necessary for optimal postoperative analgesia, a multidisciplinary approach and the management of Acute Postoperative Pain. Strategic lines and different management models are defined. A general perioperative action plan is established based on collaboration with the surgical departments involved, on the joint review of the evidence and on preparation of protocols by the procedure. Finally, a follow-up plan and a series of minimum indicators necessary for quality control of postoperative pain are presented.

Opioid-free Anesthesia Protocol on the Early Quality of Recovery after Major Surgery (SOFA Trial): A Randomized Clinical Trial

BACKGROUND

Opioid-free anesthesia is increasingly being adopted to reduce opioid consumption, but its impact on early postoperative recovery after major surgery has not been evaluated in comparative trials. The hypothesis was that an opioid-free anesthesia protocol would enhance the early quality of recovery for patients undergoing scheduled major surgery under general anesthesia.

METHODS

The SOFA study was a monocentric, randomized, controlled, assessor- and patient-blinded clinical trial conducted from July 10, 2021, to February 12, 2022. The eligible population included male and female patients undergoing scheduled major surgery, excluding bone procedures, that typically require opioids for postoperative pain management. Patients in the intervention group received a combination of at least two drugs among ketamine, lidocaine, clonidine, and magnesium sulfate, without opioids for anesthesia. The standard group received opioids. The primary outcome was early postoperative quality of recovery, assessed by Quality of Recovery-15 score at 24 h after surgery. Secondary outcomes were Quality of Recovery-15 at 48 and 72 h after surgery, incidence of chronic pain, and quality of life at 3 months.

RESULTS

Of the 136 randomized patients, 135 were included in the primary analysis (mean age, 45.9 ± 15.7 yr; 116 females [87.2%]; 85 underwent major plastic surgery [63.9%]), with 67 patients in the opioid-free anesthesia group and 68 in the standard group. The mean Quality of Recovery-15 at 24 h was 114.9 ± 15.2 in the opioid-free anesthesia group versus 108.7 ± 18.1 in the standard group (difference, 6.2; 95% CI, 0.4 to 12.0; P = 0.026). Quality of Recovery-15 scores also differed significantly at 48 h (difference, 8.7; 95% CI, 2.9 to 14.5; P = 0.004) and at 72 h (difference, 7.3; 95% CI, 1.6 to 13.0; P = 0.013). There were no differences in other secondary outcomes. No major adverse events were noticed.

CONCLUSIONS

The opioid-free anesthesia protocol improved quality of recovery after major elective surgery in a statistically but not clinically significant manner when compared to standard anesthesia.

EDITOR’S PERSPECTIVE

Ultrasound-Guided Suprazygomatic Maxillary Nerve Block Is Effective in Reducing Postoperative Opioid Use Following Bimaxillary Osteotomy

BACKGROUND

Ultrasound-guided maxillary nerve block has recently been described, though its impact upon bimaxillary osteotomy has not been formally investigated.

PURPOSE

The present study was carried out to determine whether the addition of ultrasound-guided maxillary nerve block in subjects undergoing bimaxillary osteotomy reduces opioid use.

STUDY DESIGN, SETTING, SAMPLE

A randomized clinical trial was carried out in adults undergoing bimaxillary osteotomy between April 2019 and January 2020 at Teknon Medical Center (Barcelona, Spain).

PREDICTOR VARIABLE

The predictor variable was the treatment technique used (maxillary nerve block or no block). The subjects were randomized to either receive (test group) or not receive (control group) bilateral ultrasound-guided suprazygomatic maxillary nerve block (5 ml of 0.37% ropivacaine) before surgery.

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was the intravenous methadone requirements in the first two postoperative hours. The secondary outcome variables were postoperative pain, rescue subcutaneous methadone, intravenous remifentanil used intraoperatively, the incidence of postoperative nausea-vomiting, and complications derived from maxillary nerve block.

COVARIATES

Subject age, sex, weight, height, and anesthetic risk, and the duration of surgery were recorded.

ANALYSES

Descriptive and inferential analyses were performed using the χ2 test and Mann-Whitney U test. Statistical significance was considered for P < .05.

RESULTS

The baseline sample consisted of 68 subjects scheduled for bimaxillary osteotomy. The follow-up sample comprised 60 subjects: 30 in the control group (10 females and 20 males, aged 34.0 ± 10.2 years) and 30 in the test group (13 females and 17 males, aged 29.8 ± 10.8 years). The subjects who received maxillary nerve block showed less intravenous methadone use in the first 2 hours postsurgery (median 2.0 mg control group vs 0 mg test group; P < .001), lower pain levels at any time during the first 18 hours postsurgery (median visual analog score 4 control group vs 2 test group; P < .001), and a lesser percentage required methadone (33.3% control group vs 0% test group; P < .01) at 4-18 hours postsurgery.

CONCLUSION AND RELEVANCE

The results obtained suggest that ultrasound-guided maxillary nerve block is a promising anesthetic technique capable of reducing intraoperative and postoperative opioid use, with greater patient comfort in bimaxillary osteotomy.

[Opioid-free anesthesia : Wrong track or meaningful exit from the era of opioid-based analgesia?]

The limitations and disadvantages of opioids in anesthesia are very well known but the advantages combined with a lack of effective alternatives even now still prevents refraining from using opioids as part of an adequate pain therapy. For decades, pain research has had the declared goal of replacing opioids with new substances which have no serious side effects; however, currently this goal seems to be a long way off. Due to the media coverage of the "opioid crisis" in North America, the use of opioids for pain management is also increasingly being questioned by the patients. Measures to contain this crisis are only slowly taking effect in view of the increasing number of deaths, which is why the triggers are still being sought. The perioperative administration of opioids is not only a possible gateway to addiction and abuse but it can also cause outcome-relevant complications, such as respiratory depression, postoperative nausea and vomiting and an increase in postoperative pain. Therefore, these considerations gave rise to the idea of an opioid-free anesthesia (OFA), i.e., opioids are not administered as part of anesthesia to carry out surgical procedures. Although this idea may make sense at first glance, a rapid introduction of this concept appears to be risky as it entails significant changes for the entire anesthesiological management. Based on relatively robust data from clinical studies, this concept can now be evaluated and discussed not only emotionally but also objectively. This review article presents arguments for or against the complete avoidance of intraoperative or even perioperative opioids. The current conditions in Germany are primarily taken into account, so that the perioperative pain therapy is transferable to the established standards. The results from current clinical studies on the implementation of an opioid-free anesthesia are summarized and discussed.

Ultrasound-guided erector spinae plane blocks for pain management after open lumbar laminectomy

PURPOSE

Lumbar spine surgery is associated with significant postoperative pain. The benefits of erector spinae plane blocks (ESPBs) combined with multimodal analgesia has not been adequately studied. We evaluated the analgesic effects of bilateral ESPBs as a component of multimodal analgesia after open lumbar laminectomy.

METHODS

Analgesic effects of preoperative, bilateral, ultrasound-guided ESPBs combined with standardized multimodal analgesia (n = 25) was compared with multimodal analgesia alone (n = 25) in patients undergoing one or two level open lumbar laminectomy. Other aspects of perioperative care were similar. The primary outcome measure was cumulative opioid consumption at 24 h. Secondary outcomes included opioid consumption, pain scores, and nausea and vomiting requiring antiemetics on arrival to the post-anesthesia care unit (PACU), at 24 h, 48 h, and 72 h after surgery, as well as duration of the PACU and hospital stay.

RESULTS

Opioid requirements at 24 h were significantly lower with ESPBs (31.9 ± 12.3 mg vs. 61.2 ± 29.9 mg, oral morphine equivalents). Pain scores were significantly lower with ESPBs in the PACU and through postoperative day two. Patients who received ESPBs required fewer postoperative antiemetic therapy (n = 3, 12%) compared to those without ESPBs (n = 12, 48%). Furthermore, PACU duration was significantly shorter with ESPBs (49.7 ± 9.5 vs. 79.9 ± 24.6 min).

CONCLUSIONS

Ultrasound-guided, bilateral ESPBs, when added to an optimal multimodal analgesia technique, reduce opioid consumption and pain scores, the need for antiemetic therapy, and the duration of stay in the PACU after one or two level open lumbar laminectomy.

Influence of Intravenous S-Ketamine on the Pharmacokinetics of Oral Morphine in Healthy Volunteers

BACKGROUND

Subanesthetic ketamine may reduce perioperative consumption of opioids. We studied whether intravenous S-ketamine alters the pharmacokinetics of oral morphine in healthy volunteers.

METHODS

In this paired, randomized, double-blind, crossover trial, 12 participants under a 2-hour intravenous S-ketamine (0.57 mg/kg/h) or placebo infusion received oral morphine (0.2 mg/kg) at 30 minutes. Plasma concentrations of ketamine, morphine, and their major metabolites were quantified for 24 hours. The primary end point was area under the curve (AUC) 0-24 of morphine. Other pharmacokinetic variables for morphine and its metabolites were studied as secondary end points. The data were analyzed as between-phase comparisons for each participant using Wilcoxon matched-pairs signed-rank tests ( tmax ) or paired t -tests on log-transformed variables (other variables).

RESULTS

While the AUC 0-24 was similar between the 2 phases, S-ketamine reduced the AUC 0-1.5 of oral morphine by 69% (ratio to control, 0.31; 90% confidence interval [CI], 0.15-0.65; P = .0171) and increased its tmax from 0.5 (range, 0.50-1.5) to 1.0 hour (range, 0.50-4.0; P = .010). The AUC 0-1.5 of morphine-6-glucuronide (M6G) was reduced by 84% (0.16; 90% CI, 0.07-0.37; P = .0025) and maximum plasma concentration ( Cmax ) by 43% (0.57; 90% CI, 0.40-0.81; P = .0155), while its tmax was increased from 1.5 (range, 1.0-2.0) to 4.0 (range, 1.0-8.0; P = .0094) hours by S-ketamine. Similarly, the AUC 0-1.5 of morphine-3-glucuronide (M3G) was reduced by 85% (0.15; 90% CI, 0.05-0.43; P = .0083), and tmax increased from 1.0 (range, 0.5-1.5) to 4.0 hours (range, 1.0-8.0; P = .0063). In addition, the M6G-to-morphine and M3G-to-morphine metabolic AUC ratios were decreased by 47% (0.53; 90% CI, 0.39-0.71; P = .0033) and 52% (0.48; 90% CI, 0.27-0.85; P = .0043) during 0 to 1.5 hours and by 15% (0.85; 90% CI, 0.78-0.92; P = .0057) and 10% (0.90; 90% CI, 0.83-0.98; P = .0468) during 0 to 24 hours, respectively. One participant was excluded from the analyses due to vomiting in the S-ketamine phase.

CONCLUSIONS

Intravenous S-ketamine inhibited the metabolism of oral morphine and delayed its absorption, resulting in a net reduction in the exposure to morphine during the first 1.5 hours. Intravenous S-ketamine may delay the absorption and impair the efficacy of orally administered analgesics and other drugs.

Opioid reduction and enhanced recovery in orthopaedic surgery (OREOS): a protocol for a feasibility randomised controlled trial in patients undergoing total knee arthroplasty

BACKGROUND

Knee arthritis is a leading cause of limited function and long-term disability in older adults. Despite a technically successful total knee arthroplasty (TKA), around 20% of patients continue to have persisting pain with reduced function, and low quality of life. Many of them continue using opioids for pain control, which puts them at risk for potential long-term adverse effects such as dependence, overdose and risk of falls. Although persisting pain and opioid use after TKA have been recognised to be important issues, individual strategies to decrease their burden have limitations and multi-component interventions, despite their potential, have not been well studied. In this study, we propose a multi-component pathway including personalized pain management, facilitated by a pain management coordinator. The objectives of this pilot trial are to evaluate feasibility (recruitment, retention, and adherence), along with opioid-free pain control at 8 weeks after TKA.

METHODS

This is a protocol for a multicentre pilot randomised controlled trial using a 2-arm parallel group design. Adult participants undergoing unilateral total knee arthroplasty will be considered for inclusion and randomised to control and intervention groups. Participants in the intervention group will receive support from a pain management coordinator who will facilitate a multicomponent pain management pathway including (1) preoperative education on pain and opioid use, (2) preoperative risk identification and mitigation, (3) personalized post-discharge analgesic prescriptions and (4) continued support for pain control and recovery up to 8 weeks post-op. Participants in the control group will undergo usual care. The primary outcomes of this pilot trial are to assess the feasibility of participant recruitment, retention, and adherence to the interventions, and key secondary outcomes are persisting pain and opioid use.

DISCUSSION

The results of this trial will determine the feasibility of conducting a definitive trial for the implementation of a multicomponent pain pathway to improve pain control and reduce harms using a coordinated approach, while keeping an emphasis on patient centred care and shared decision making.

TRIAL REGISTRATION

Prospectively registered in Clinicaltrials.gov (NCT04968132).

Esketamine combined with sufentanil versus sufentanil in patient-controlled intravenous analgesia: a meta-analysis

Objective: Patient-controlled intravenous analgesia (PCIA) can alleviate pain to some extent, and several randomized controlled trials (RCTs) have examined the efficacy of esketamine-assisted sufentanil in postoperative PCIA. In this research, we conducted a meta-analysis of relevant RCTs to compare the effect and safety of esketamine-sufentanil versus sufentanil alone for postoperative PCIA. Methods: We systematically searched the Cochrane Library, PubMed, Embase, Web of Science, CNKI, and other libraries up to December 2023 to screen out RCTs examining the use of esketamine combined with sufentanil for PCIA. We analysed analgesia scores, sedation scores, adverse drug reactions and postpartum depression scores as outcome indicators. Results: This meta-analysis included 32 RCTs. The results of the meta-analysis were as follows. 1) Visual Analog Scale: The VAS scores at 6, 12, 24, and 48 h were lower in the esketamine-sufentanil group than in the sufentanil alone group, and significant differences were found at all time points (p < 0.05). 2) Ramsay Sedation Scale: The sedation score of the esketamine-sufentanil group at 48 h after surgery was higher than that of the sufentanil group alone [mean difference (MD) = -0.09 points, confidence interval (CI): (-0.26, -0.07), p = 0.27], but this difference was not significant (p > 0.05). 3) Safety: Compared with sufentanil alone, the incidence rates of postoperative nausea-vomiting, dizziness-headache, skin pruritus and respiratory depression were significantly lower in the esketamine-sufentanil group. 4) Postartum depression: The reduction in postpartum depression scores were significantly greater in the esketamine-sufentanil group than in the sufentanil alone group at 3 days [MD = -1.35 points, CI: (-1.89, -0.81), p < 0.00001] and 7 days [MD = -1.29 points, CI: (-2.42, -0.16), p = 0.03]. Conclusion: The meta-analysis showed that the use of esketamine combined with sufentanil for postoperative PCIA could improve postoperative analgesia, alleviate postpartum depression and reduce the rate of postoperative adverse reactions, but there was no significant difference in sedation.

Cold nociception as a measure of hyperalgesia during spontaneous heroin withdrawal in mice

Opioids are powerful analgesic drugs that are used clinically to treat pain. However, chronic opioid use causes compensatory neuroadaptations that result in greater pain sensitivity during withdrawal, known as opioid withdrawal-induced hyperalgesia (OWIH). Cold nociception tests are commonly used in humans, but preclinical studies often use mechanical and heat stimuli to measure OWIH. Thus, further characterization of cold nociception stimuli is needed in preclinical models. We assessed three cold nociception tests-thermal gradient ring (5-30 °C, 5-50 °C, 15-40 °C, and 25-50 °C), dynamic cold plate (4 °C to -1 °C at -1 °C/min, -1 °C to 4 °C at +1 °C/min), and stable cold plate (10 °C, 6 °C, and 2 °C)-to measure hyperalgesia in a mouse protocol of heroin dependence. On the thermal gradient ring, mice in the heroin withdrawal group preferred warmer temperatures, and the results depended on the ring's temperature range. On the dynamic cold plate, heroin withdrawal increased the number of nociceptive responses, with a temperature ramp from 4 °C to -1 °C yielding the largest response. On the stable cold plate, heroin withdrawal increased the number of nociceptive responses, and a plate temperature of 2 °C yielded the most significant increase in responses. Among the three tests, the stable cold plate elicited the most robust change in behavior between heroin-dependent and nondependent mice and had the highest throughput. To pharmacologically characterize the stable cold plate test, we used μ-opioid and non-opioid receptor-targeting drugs that have been previously shown to reverse OWIH in mechanical and heat nociception assays. The full μ-opioid receptor agonist methadone and μ-opioid receptor partial agonist buprenorphine decreased OWIH, whereas the preferential μ-opioid receptor antagonist naltrexone increased OWIH. Two N-methyl-d-aspartate receptor antagonists (ketamine, MK-801), a corticotropin-releasing factor 1 receptor antagonist (R121919), a β2-adrenergic receptor antagonist (butoxamine), an α2-adrenergic receptor agonist (lofexidine), and a 5-hydroxytryptamine-3 receptor antagonist (ondansetron) had no effect on OWIH. These data demonstrate that the stable cold plate at 2 °C yields a robust, reliable, and concise measure of OWIH that is sensitive to opioid agonists.

The Impact of Nociception Monitor-Guided Multimodal General Anesthesia on Postoperative Outcomes in Patients Undergoing Laparoscopic Bowel Surgery: A Randomized Controlled Trial

BACKGROUND

Excess surgical stress responses, caused by heightened nociception, can lead to elevated levels of postoperative inflammation, resulting in an increased incidence of complications after surgery. We hypothesized that utilizing nociception monitor-guided multimodal general anesthesia would exert effects on postoperative outcomes (e.g., serum concentrations of C-reactive protein (CRP) after surgery, postoperative complications).

METHODS

This single-center, double-blinded, randomized trial enrolled ASA class I/II adult patients with normal preoperative CRP levels, scheduled for laparoscopic bowel surgery. Patients were randomized to receive either standard care (control group) or nociception monitor-guided multimodal general anesthesia using the nociceptive response (NR) index (NR group), where NR index was kept below 0.85 as possible. The co-primary endpoint was serum concentrations of CRP after surgery or rates of 30-day postoperative complications (defined as Clavien-Dindo grades ≥ II).

MAIN RESULTS

One hundred and four patients (control group, n = 52; NR group, n = 52) were enrolled for analysis. The serum CRP level on postoperative day (POD) 1 was significantly lower in the NR group (2.70 mg·dL-1 [95% confidence interval (CI), 2.19-3.20]) than in the control group (3.66 mg·dL-1 [95% CI, 2.98-4.34], p = 0.024). The postoperative complication rate was also significantly lower in the NR group (11.5% [95% CI, 5.4-23.0]) than in the control group (38.5% [95% CI, 26.5-52.0], p = 0.002).

CONCLUSIONS

Nociception monitor-guided multimodal general anesthesia, which suppressed intraoperative nociception, mitigated serum concentrations of CRP level, and decreased postoperative complications after laparoscopic bowel surgery.

Variation in Intraoperative Opioid Administration by Patient, Clinician, and Hospital Contribution

Importance

The opioid crisis has led to scrutiny of opioid exposures before and after surgical procedures. However, the extent of intraoperative opioid variation and the sources and contributing factors associated with it are unclear.

Objective

To analyze attributable variance of intraoperative opioid administration for patient-, clinician-, and hospital-level factors across surgical and analgesic categories.

Design, Setting, and Participants

This cohort study was conducted using electronic health record data collected from a national quality collaborative database. The cohort consisted of 1 011 268 surgical procedures at 46 hospitals across the US involving 2911 anesthesiologists, 2291 surgeons, and 8 surgical and 4 analgesic categories. Patients without ambulatory opioid prescriptions or use history undergoing an elective surgical procedure between January 1, 2014, and September 11, 2020, were included. Data were analyzed from January 2022 to July 2023.

Main Outcomes and Measures

The rate of intraoperative opioid administration as a continuous measure of oral morphine equivalents (OMEs) normalized to patient weight and case duration was assessed. Attributable variance was estimated in a hierarchical structure using patient, clinician, and hospital levels and adjusted intraclass correlations (ICCs).

Results

Among 1 011 268 surgical procedures (mean [SD] age of patients, 55.9 [16.2] years; 604 057 surgical procedures among females [59.7%]), the mean (SD) rate of intraoperative opioid administration was 0.3 [0.2] OME/kg/h. Together, clinician and hospital levels contributed to 20% or more of variability in intraoperative opioid administration across all analgesic and surgical categories (adjusting for surgical or analgesic category, ICCs ranged from 0.57-0.79 for the patient, 0.04-0.22 for the anesthesiologist, and 0.09-0.26 for the hospital, with the lowest ICC combination 0.21 for anesthesiologist and hosptial [0.12 for the anesthesiologist and 0.09 for the hospital for opioid only]). Comparing the 95th and fifth percentiles of opioid administration, variation was 3.3-fold among anesthesiologists (surgical category range, 2.7-fold to 7.7-fold), 4.3-fold among surgeons (surgical category range, 3.4-fold to 8.0-fold), and 2.2-fold among hospitals (surgical category range, 2.2-fold to 4.3-fold). When adjusted for patient and surgical characteristics, mean (square error mean) administration was highest for cardiac surgical procedures (0.54 [0.56-0.52 OME/kg/h]) and lowest for orthopedic knee surgical procedures (0.19 [0.17-0.21 OME/kg/h]). Peripheral and neuraxial analgesic techniques were associated with reduced administration in orthopedic hip (51.6% [95% CI, 51.4%-51.8%] and 60.7% [95% CI, 60.5%-60.9%] reductions, respectively) and knee (48.3% [95% CI, 48.0%-48.5%] and 60.9% [95% CI, 60.7%-61.1%] reductions, respectively) surgical procedures, but reduction was less substantial in other surgical categories (mean [SD] reduction, 13.3% [8.8%] for peripheral and 17.6% [9.9%] for neuraxial techniques).

Conclusions and Relevance

In this cohort study, clinician-, hospital-, and patient-level factors had important contributions to substantial variation of opioid administrations during surgical procedures. These findings suggest the need for a broadened focus across multiple factors when developing and implementing opioid-reducing strategies in collaborative quality-improvement programs.

Pain management and opioid stewardship in adult cardiac surgery: Joint consensus report of the PeriOperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society

BACKGROUND

Opioid-based anesthesia and analgesia is a traditional component of perioperative care for the cardiac surgery patient. Growing enthusiasm for Enhanced Recovery Programs (ERPs) coupled with evidence of potential harm associated with high-dose opioids suggests that we reconsider the role of opioids in cardiac surgery.

METHODS

An interdisciplinary North American panel of experts, using a structured appraisal of the literature and a modified Delphi method, derived consensus recommendations for optimal pain management and opioid stewardship for cardiac surgery patients. Individual recommendations are graded based on the strength and level of evidence.

RESULTS

The panel addressed 4 main topics: the harms associated with historical opioid use, the benefits of more targeted opioid administration, the use of nonopioid medications and techniques, and patient and provider education. A key principle that emerged is that opioid stewardship should apply to all cardiac surgery patients, entailing judicious and targeted use of opioids to achieve optimal analgesia with the fewest potential side effects. The process resulted in the promulgation of 6 recommendations regarding pain management and opioid stewardship in cardiac surgery, focused on avoiding the use of high-dose opioids, as well as encouraging more widespread application of foundational aspects of ERPs, such as the use of multimodal nonopioid medications and regional anesthesia techniques, formal patient and provider education, and structured system-level opioid prescription practices.

CONCLUSIONS

Based on the available literature and expert consensus, there is an opportunity to optimize anesthesia and analgesia for cardiac surgery patients. Although additional research is needed to establish specific strategies, core principles of pain management and opioid stewardship apply to the cardiac surgery population.

The nuts and bolts of multimodal anaesthesia in the 21st century: a primer for clinicians

PURPOSE OF REVIEW

This review article explores the application of multimodal anaesthesia in general anaesthesia, particularly in conjunction with locoregional anaesthesia, specifically focusing on the importance of EEG monitoring. We provide an evidence-based guide for implementing multimodal anaesthesia, encompassing drug combinations, dosages, and EEG monitoring techniques, to ensure reliable intraoperative anaesthesia while minimizing adverse effects and improving patient outcomes.

RECENT FINDINGS

Opioid-free and multimodal general anaesthesia have significantly reduced opioid addiction and chronic postoperative pain. However, the evidence supporting the effectiveness of these approaches is limited. This review attempts to integrate research from broader neuroscientific fields to generate new clinical hypotheses. It discusses the correlation between high-dose intraoperative opioids and increased postoperative opioid consumption and their impact on pain indices and readmission rates. Additionally, it explores the relationship between multimodal anaesthesia and pain processing models and investigates the potential effects of nonpharmacological interventions on preoperative anxiety and postoperative pain.

SUMMARY

The integration of EEG monitoring is crucial for guiding adequate multimodal anaesthesia and preventing excessive anaesthesia dosing. Furthermore, the review investigates the impact of combining regional and opioid-sparing general anaesthesia on perioperative EEG readings and anaesthetic depth. The findings have significant implications for clinical practice in optimizing multimodal anaesthesia techniques (Supplementary Digital Content 1: Video Abstract, http://links.lww.com/COAN/A96 ).

Additional pre-extubation local anaesthetic application to improve the postoperative course in orthognathic surgery: a randomised controlled trial

A clinical trial was performed to assess the analgesic efficacy of adding ropivacaine pre-extubation for pain management after bimaxillary osteotomy. Forty-eight patients were assigned to receive general anaesthesia followed by either a single pre-incisional infiltration with lidocaine (control group, n = 24) or the same pre-incisional infiltration with lidocaine and an additional second infiltration with ropivacaine before awakening (test group, n = 24). Postoperative pain was assessed subjectively using a visual analogue scale and objectively based on the frequency of postoperative rescue opioid consumption. The dose of opioids (methadone) consumed and frequency of postoperative-nausea-vomiting were also recorded. Patients who received the two infiltrations of local anaesthetic had better results in terms of lesser pain during the first 8 hours postoperative (P<0.001 at 2 and 4 hours; P = 0.028 at 8 h), a lesser need for rescue opioids (P = 0.020) and lower doses of rescue opioids (P = 0.011), and consequently a lesser incidence of postoperative-nausea-vomiting (0-4 hours postoperative, P<0.03). The results obtained suggest that the infiltration of an additional dose of local anaesthetic is a simple strategy for reducing pain perception and opioid use, and for ensuring greater patient comfort after bimaxillary osteotomy.

Intraoperative Methadone in Next-day Discharge Outpatient Surgery: A Randomized, Double-blinded, Dose-finding Pilot Study

BACKGROUND

Contemporary perioperative practice seeks to use less intraoperative opioid, diminish postoperative pain and opioid use, and enable less postdischarge opioid prescribing. For inpatient surgery, anesthesia with intraoperative methadone, compared with short-duration opioids, results in less pain, less postoperative opioid use, and greater patient satisfaction. This pilot investigation aimed to determine single-dose intraoperative methadone feasibility for next-day discharge outpatient surgery, determine an optimally analgesic and well-tolerated dose, and explore whether methadone would result in less postoperative opioid use compared with conventional short-duration opioids.

METHODS

This double-blind, randomized, dose-escalation feasibility and pilot study in next-day discharge surgery compared intraoperative single-dose IV methadone (0.1 then 0.2, 0.25 and 0.3 mg/kg ideal body weight) versus as-needed short-duration opioid (fentanyl, hydromorphone) controls. Perioperative opioid use, pain, and side effects were assessed before discharge. Patients recorded pain, opioid use, and side effects for 30 days postoperatively using take-home diaries. Primary clinical outcome was in-hospital (intraoperative and postoperative) opioid use. Secondary outcomes were 30-day opioid consumption, pain, opioid side effects, and leftover opioid counts.

RESULTS

Median (interquartile range) intraoperative methadone doses were 6 (5 to 7), 11 (10 to 12), 14 (13 to 16), and 18 (15 to 19) mg in 0.1, 0.2, 0.25, and 0.3 mg/kg ideal body weight groups, respectively. Anesthesia with single-dose methadone and propofol or volatile anesthetic was effective. Total in-hospital opioid use (IV milligram morphine equivalents [MME]) was 25 (20 to 37), 20 (13 to 30), 27 (18 to 32), and 25 (20 to 36) mg, respectively, in patients receiving 0.1, 0.2, 0.25 and 0.3 mg/kg methadone, compared to 46 (33 to 59) mg in short-duration opioid controls. Opioid-related side effects were not numerically different. Home pain and opioid use were numerically lower in patients receiving methadone.

CONCLUSIONS

The most effective and well-tolerated single intraoperative induction dose of methadone for next-day discharge surgery was 0.25 mg/kg ideal body weight (median, 14 mg). Single-dose intraoperative methadone was analgesic and opioid-sparing in next-day discharge outpatient surgery.

EDITOR’S PERSPECTIVE

The Effect of Upper Extremity Tourniquet Time on Postoperative Pain and Opiate Consumption

BACKGROUND

There is widespread use of pneumatic tourniquet for both upper and lower extremity orthopedic surgeries. Tourniquet use improves visualization, decreases blood loss, and as a result, decreases operative time. Exceeding a certain amount of tourniquet time can cause lasting neuromuscular damage. Orthopedic procedures cause significant pain, and the perioperative narcotic prescriptions after orthopedic surgery have been identified as one of the major contributors to the opioid epidemic. Our aim was to determine whether increasing tourniquet time had a negative impact on immediate postoperative opiate usage in the upper extremity, and to determine other factors associated with increased immediate postoperative opiate usage.

METHODS

A retrospective medical record review was performed on patients who underwent volar pleading for fracture fixation between January 2014 and December 2019 at a single institution. Postoperative pain, morphine equivalent dose (MED) usage, and demographic variables were collected. Multivariable analysis was performed, with P < .05 considered significant.

RESULTS

Immediate postoperative MED consumed was not correlated with operative time, tourniquet time, preoperative substance usage, or sex. However, postoperative MED consumed was correlated with preoperative narcotic use, high body mass index (BMI), and fracture surgery complexity.

CONCLUSIONS

Tourniquet usage under current guidelines does not appear to have an effect on postoperative pain and narcotic usage. Preoperative narcotic usage, BMI, and surgery complexity are significant factors for postoperative opiate consumption.

Pain management after cardiac surgery via median sternotomy: A systematic review with procedure-specific postoperative pain management (PROSPECT) recommendations

BACKGROUND

Pain after cardiac surgery via median sternotomy can be difficult to treat, and if inadequately managed can lead to respiratory complications, prolonged hospital stays and chronic pain.

OBJECTIVES

To evaluate available literature and develop recommendations for optimal pain management after cardiac surgery via median sternotomy.

DESIGN

A systematic review using PROcedure-SPECific Pain Management (PROSPECT) methodology.

ELIGIBILITY CRITERIA

Randomised controlled trials and systematic reviews published in the English language until November 2020 assessing postoperative pain after cardiac surgery via median sternotomy using analgesic, anaesthetic or surgical interventions.

DATA SOURCES

PubMed, Embase and Cochrane Databases.

RESULTS

Of 319 eligible studies, 209 randomised controlled trials and three systematic reviews were included in the final analysis. Pre-operative, intra-operative and postoperative interventions that reduced postoperative pain included paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), intravenous magnesium, intravenous dexmedetomidine and parasternal block/infiltration.

CONCLUSIONS

The analgesic regimen for cardiac surgery via sternotomy should include paracetamol and NSAIDs, unless contraindicated, administered intra-operatively and continued postoperatively. Intra-operative magnesium and dexmedetomidine infusions may be considered as adjuncts particularly when basic analgesics are not administered. It is not clear if combining dexmedetomidine and magnesium would provide superior pain relief compared with either drug alone. Parasternal block/surgical site infiltration is also recommended. However, no basic analgesics were used in the studies assessing these interventions. Opioids should be reserved for rescue analgesia. Other interventions, including cyclo-oxygenase-2 specific inhibitors, are not recommended because there was insufficient, inconsistent or no evidence to support their use and/or due to safety concerns.

The Perioperative Pain Management Bundle is Feasible: Findings From the PAIN OUT Registry

OBJECTIVES

The quality of postoperative pain management is often poor. A "bundle," a small set of evidence-based interventions, is associated with improved outcomes in different settings. We assessed whether staff caring for surgical patients could implement a "Perioperative Pain Management Bundle" and whether this would be associated with improved multidimensional pain-related patient-reported outcomes (PROs).

METHODS

"PAIN OUT," a perioperative pain registry, offers tools for auditing pain-related PROs and obtaining information about perioperative pain management during the first 24 hours after surgery. Staff from 10 hospitals in Serbia used this methodology to collect data at baseline. They then implemented the "Perioperative Pain Management Bundle" into the clinical routine and collected another round of data. The bundle consists of 4 treatment elements: (1) a full daily dose of 1 to 2 nonopioid analgesics (eg, paracetamol and/or nonsteroidal anti-inflammatory drugs), (2) at least 1 type of local/regional anesthesia, (3) pain assessment by staff, and (4) offering patients information about pain management. The primary endpoint was a multidimensional pain composite score (PCS), evaluating pain intensity, interference, and side effects that was compared between patients who received the full bundle versus not.

RESULTS

Implementation of the complete bundle was associated with a significant reduction in the PCS ( P < 0.001, small-medium effect size [ES]). When each treatment element was evaluated independently, nonopioid analgesics were associated with a higher PCS (ie, poorer outcome, and negligible ES), and the other elements were associated with a lower PCS (all negligible small ES). Individual PROs were consistently better in patients receiving the full bundle compared with 0 to 3 elements. The PCS was not associated with the surgical discipline.

DISCUSSION

We report findings from using a bundle approach for perioperative pain management in patients undergoing mixed surgical procedures. Future work will seek strategies to improve the effect.

Outcomes for 41 260 pediatric surgical patients with opioid-free anesthesia: One center's experience

BACKGROUND

Opioid use is common and associated with side effects and risks. Consequently, analgesic strategies to reduce opioid utilization have been developed. Regional anesthesia and multimodal strategies are central tenets of enhanced recovery pathways and facilitate reduced perioperative opioid use. Opioid-free anesthesia (OFA) protocols eliminate all intraoperative opioids, reserving opioids for postoperative rescue treatment. Systematic reviews show variable results for OFA.

METHODS

In a series of Quality Improvement (QI) projects, multidisciplinary teams developed interventions to test and spread OFA first in our ambulatory surgery center (ASC) and then in our hospital. Outcome measures were tracked using statistical process control charts to increase the adoption of OFA.

RESULTS

Between January 1, 2016, and September 30, 2022, 19 872 of 28 574 ASC patients received OFA, increasing from 30% to 98%. Post Anesthesia Care Unit (PACU) maximum pain score, opioid-rescue rate, and postoperative nausea and vomiting (PONV) treatment all decreased concomitantly. The use of OFA now represents our ambulatory standard practice. Over the same timeframe, the spread of this practice to our hospital led to 21 388 of 64 859 patients undergoing select procedures with OFA, increasing from 15% to 60%. Opioid rescue rate and PONV treatment in PACU decreased while hospital maximum pain scores and length of stay were stable. Two procedural examples with OFA benefits were identified. The use of OFA allowed relaxation of adenotonsillectomy admission criteria, resulting in 52 hospital patient days saved. Transition to OFA for laparoscopic appendectomy occurred concomitantly with a decrease in the mean hospital length of stay from 2.9 to 1.4 days, representing a savings of >500 hospital patient days/year.

CONCLUSIONS

These QI projects demonstrated that most pediatric ambulatory and select inpatient surgeries are amenable to OFA techniques which may reduce PONV without worsening pain.

Opioid analgesic effects on subjective well-being in the operating theatre

Exposure to opioid analgesics due to surgery increases the risk of new persistent opioid use. A mechanistic hypothesis for opioids' abuse liability rests on the belief that, in addition to pain relief, acute opioid treatment improves well-being (e.g. via euphoria) and relieves anxiety. However, opioids do not consistently improve mood in laboratory studies of healthy non-opioid users. This observational study determined how two commonly used opioid analgesics affected patients' subjective well-being in standard clinical practice. Day surgery patients rated how good and how anxious they felt before and after an open-label infusion of remifentanil (n = 159) or oxycodone (n = 110) in the operating theatre before general anaesthesia. One minute after drug injection, patients reported feeling intoxicated (> 6/10 points). Anxiety was reduced after opioids, but this anxiolytic effect was modest (remifentanil Cohen's d = 0.21; oxycodone d = 0.31). There was moderate to strong evidence against a concurrent improvement in well-being (Bayes factors > 6). After remifentanil, ratings of 'feeling good' were significantly reduced from pre-drug ratings (d = 0.28). After oxycodone, one in three participants felt better than pre-drug. Exploratory ordered logistic regressions revealed a link between previous opioid exposure and opioid effects on well-being, as only 14 of the 80 opioid-naïve patients reported feeling better after opioid injection. The odds of improved well-being ratings after opioids were higher in patients with previous opioid exposure and highest in patients with > 2 weeks previous opioid use (adjusted OR = 4.4). These data suggest that opioid-induced improvement of well-being is infrequent in opioid-naïve patients. We speculate that peri-operative exposure could increase risk of persistent use by rendering subsequent positive opioid effects on well-being more likely.

Day-surgery adult patients with obesity and obstructive sleep apnea: Current controversies and concerns

Obesity and obstructive sleep apnea are considered independent risk factors that can adversely affect perioperative outcomes. A combination of these two conditions in the ambulatory surgery patient can pose significant challenges for the anesthesiologist. Nevertheless, these patients should not routinely be denied access to ambulatory surgery. Instead, patients should be appropriately optimized. Anesthesiologists and surgeons must work together to implement fast-track anesthetic and surgical techniques that will ensure successful ambulatory outcomes.

Association of Intraoperative Opioid Administration With Postoperative Pain and Opioid Use

IMPORTANCE

Opioids administered to treat postsurgical pain are a major contributor to the opioid crisis, leading to chronic use in a considerable proportion of patients. Initiatives promoting opioid-free or opioid-sparing modalities of perioperative pain management have led to reduced opioid administration in the operating room, but this reduction could have unforeseen detrimental effects in terms of postoperative pain outcomes, as the relationship between intraoperative opioid usage and later opioid requirements is not well understood.

OBJECTIVE

To characterize the association between intraoperative opioid usage and postoperative pain and opioid requirements.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study evaluated electronic health record data from a quaternary care academic medical center (Massachusetts General Hospital) for adult patients who underwent noncardiac surgery with general anesthesia from April 2016 to March 2020. Patients who underwent cesarean surgery, received regional anesthesia, received opioids other than fentanyl or hydromorphone, were admitted to the intensive care unit, or who died intraoperatively were excluded. Statistical models were fitted on the propensity weighted data set to characterize the effect of intraoperative opioid exposures on primary and secondary outcomes. Data were analyzed from December 2021 to October 2022.

EXPOSURES

Intraoperative fentanyl and intraoperative hydromorphone average effect site concentration estimated using pharmacokinetic/pharmacodynamic models.

MAIN OUTCOMES AND MEASURES

The primary study outcomes were the maximal pain score during the postanesthesia care unit (PACU) stay and the cumulative opioid dose, quantified in morphine milligram equivalents (MME), administered during the PACU stay. Medium- and long-term outcomes associated with pain and opioid dependence were also evaluated.

RESULTS

The study cohort included a total of 61 249 individuals undergoing surgery (mean [SD] age, 55.44 [17.08] years; 32 778 [53.5%] female). Increased intraoperative fentanyl and intraoperative hydromorphone were both associated with reduced maximum pain scores in the PACU. Both exposures were also associated with a reduced probability and reduced total dosage of opioid administration in the PACU. In particular, increased fentanyl administration was associated with lower frequency of uncontrolled pain; a decrease in new chronic pain diagnoses reported at 3 months; fewer opioid prescriptions at 30, 90, and 180 days; and decreased new persistent opioid use, without significant increases in adverse effects.

CONCLUSIONS AND RELEVANCE

Contrary to prevailing trends, reduced opioid administration during surgery may have the unintended outcome of increasing postoperative pain and opioid consumption. Conversely, improvements in long-term outcomes might be achieved by optimizing opioid administration during surgery.

The effect of opioid-free anaesthesia on the quality of recovery after endoscopic sinus surgery: A multicentre randomised controlled trial

BACKGROUND

It remains to be determined whether opioid-free anaesthesia (OFA) is consistently effective for different types of surgery.

OBJECTIVES

The current study hypothesised that OFA could effectively inhibit intraoperative nociceptive responses, reduce side effects associated with opioid use, and improve the quality of recovery (QoR) in endoscopic sinus surgery (ESS).

DESIGN

A multicentre randomised controlled study.

SETTING

Seven hospitals participated in this multicentre trial from May 2021 to December 2021.

PATIENTS

Of the 978 screened patients who were scheduled for elective ESS, 800 patients underwent randomisation, and 773 patients were included in the analysis; 388 patients in the OFA group and 385 patients in the opioid anaesthesia group.

INTERVENTIONS

The OFA group received balanced anaesthesia with dexmedetomidine, lidocaine, propofol and sevoflurane; the opioid anaesthesia group received opioid-based balanced anaesthesia using sufentanil, remifentanil, propofol and sevoflurane.

OUTCOME MEASURES

The primary outcome was 24-h postoperative QoR as evaluated by the Quality of Recovery-40 questionnaire. The key secondary outcomes were episodes of postoperative pain and postoperative nausea and vomiting (PONV).

RESULTS

A significant difference (P = 0.0014) in the total score of 24-h postoperative Quality of Recovery-40 was found between the OFA group, median [interquartile range], 191 [185 to 196] and the opioid anaesthesia group (194 [187 to 197]). There were significant differences between the opioid anaesthesia group and the OFA group in the numerical rating scale score for pain after surgery at 30 min (P  = 0.0017), 1 h (P  = 0.0052), 2 h (P  = 0.0079) and 24 h (P = 0.0303). The difference in the area under the curve of pain scale scores between the OFA group (24.2 [3.0 to 47.5]) and the opioid anaesthesia group (11.5 [1.0 to 39.0]) was significant (P = 0.0042). PONV occurred in 58 of 385 patients (15.1%) in the opioid anaesthesia group compared with 27 of 388 patients (7.0%) in the OFA group, suggesting the incidence of PONV in the OFA group was significantly lower than in the opioid anaesthesia group (P  = 0.0021).

CONCLUSION

OFA can provide good intraoperative analgesia and postoperative recovery quality as effectively as conventional opioid anaesthesia in patients undergoing ESS. OFA can be an alternative option in the pain management of ESS.

TRIAL REGISTRATION

The study was registered at the Chinese Clinical Trial Registry (ChiCTR2100046158; registry URL: http://www.chictr.org.cn/enIndex.aspx.).

Intravenous Methadone for Perioperative and Chronic Cancer Pain: A Review of the Literature

Intravenous methadone may be useful in acute and chronic pain management compared with other opioids because of its pharmacokinetic and pharmacodynamic characteristics, including the long duration of effect and ability to modulate both pain stimuli propagation and analgesic descending pathways. However, methadone is underused in pain medicine because of several misperceptions. A review of studies was performed to assess data regarding the use of methadone in perioperative pain and chronic cancer pain. The majority of studies have shown that intravenous methadone produces an effective postoperative analgesia and lowers opioid consumption in the postoperative period, without more adverse effects in comparison with other opioid analgesics, and has an interesting potential to prevent persistent postoperative pain. A minority of studies investigated the use of intravenous methadone for cancer pain management. These studies were mostly case series that showed promising activities of intravenous methadone for difficult pain conditions. There is sufficient evidence suggesting that intravenous methadone is effective in perioperative pain, while more studies are needed in patients with cancer pain.

The role of preoperative opioid use in shoulder surgery-A systematic review

Background

Emerging evidence suggests preoperative opioid use may increase the risk of negative outcomes following orthopedic procedures. This systematic review evaluated the impact of preoperative opioid use in patients undergoing shoulder surgery with respect to preoperative clinical outcomes, postoperative complications, and postoperative dependence on opioids.

Methods

EMBASE, MEDLINE, CENTRAL, and CINAHL were searched from inception to April, 2021 for studies reporting preoperative opioid use and its effect on postoperative outcomes or opioid use. The search, data extraction and methodologic assessment were performed in duplicate for all included studies.

Results

Twenty-one studies with a total of 257,301 patients were included in the final synthesis. Of which, 17 were level III evidence. Of those, 51.5% of the patients reported pre-operative opioid use. Fourteen studies (66.7%) reported a higher likelihood of opioid use at follow-up among those used opioids preoperatively compared to preoperative opioid-naïve patients. Eight studies (38.1%) showed lower functional measurements and range of motion in opioid group compared to the non-opioid group post-operatively.

Conclusion

Preoperative opioid use in patients undergoing shoulder surgeries is associated with lower functional scores and post-operative range of motion. Most concerning is preoperative opioid use may predict increased post-operative opioid requirements and potential for misuse in patients.

Level of evidence

Level IV, Systematic review.

Opioids and opioid receptors; understanding pharmacological mechanisms as a key to therapeutic advances and mitigation of the misuse crisis

Opioids are a mainstay in acute pain management and produce their effects and side effects (e.g., tolerance, opioid-use disorder and immune suppression) by interaction with opioid receptors. I will discuss opioid pharmacology in some controversial areas of enquiry of anaesthetic relevance. The main opioid target is the µ (mu,MOP) receptor but other members of the opioid receptor family, δ (delta; DOP) and κ (kappa; KOP) opioid receptors also produce analgesic actions. These are naloxone-sensitive. There is important clinical development relating to the Nociceptin/Orphanin FQ (NOP) receptor, an opioid receptor that is not naloxone-sensitive. Better understanding of the drivers for opioid effects and side effects may facilitate separation of side effects and production of safer drugs. Opioids bind to the receptor orthosteric site to produce their effects and can engage monomer or homo-, heterodimer receptors. Some ligands can drive one intracellular pathway over another. This is the basis of biased agonism (or functional selectivity). Opioid actions at the orthosteric site can be modulated allosterically and positive allosteric modulators that enhance opioid action are in development. As well as targeting ligand-receptor interaction and transduction, modulating receptor expression and hence function is also tractable. There is evidence for epigenetic associations with different types of pain and also substance misuse. As long as the opioid narrative is defined by the 'opioid crisis' the drive to remove them could gather pace. This will deny use where they are effective, and access to morphine for pain relief in low income countries.

Esketamine opioid-free intravenous anesthesia versus opioid intravenous anesthesia in spontaneous ventilation video-assisted thoracic surgery: a randomized controlled trial

Background

Opioid-free anesthesia (OFA) provides adequate analgesia and can reduce postoperative opioid consumption, but its efficacy in spontaneous ventilation video-assisted thoracic surgery (SV-VATS) has not been demonstrated. We aimed to investigate the hypothesis that OFA could provide the same perioperative pain control as opioid anesthesia (OA), maintain safe and stable respiration and hemodynamics during surgery, and improve postoperative recovery.

Methods

Sixty eligible patients (OFA group: n=30; OA group: n=30) treated between September 15, 2022, and December 15, 2022, at The First Hospital of Guangzhou Medical University were included. They were randomized to receive standard balanced OFA with esketamine or OA with remifentanil combined with sufentanil. The primary outcome was the pain numeric rating score (NRS) at postoperative 24 h, and the secondary outcomes were intraoperative respiratory and hemodynamic data, opioid consumption, vasoactive drug dosage, and recovery in the post-anesthesia care unit and ward.

Results

There was no significant difference in the postoperative pain scores and recovery quality between the two groups. The OFA group had a significantly lower dose of phenylephrine (P=0.001) and a lower incidence of hypotension (P=0.004) during surgery. The OFA group resumed spontaneous respiration faster (P<0.001) and had a higher quality of lung collapse (P=0.02). However, the total doses of propofol and dexmetomidine were higher (P=0.03 and P=0.02), and the time to consciousness was longer (P=0.039) in the OFA group.

Conclusions

OFA provides the same level of postoperative pain control as OA, but it is more advantageous in maintaining circulatory and respiratory stability and improving the quality of pulmonary collapse in SV-VATS.

Distinct Profiles of Desensitization of µ-Opioid Receptors Caused by Remifentanil or Fentanyl: In Vitro Assay with Cells and Three-Dimensional Structural Analyses

Remifentanil (REM) and fentanyl (FEN) are commonly used analgesics that act by activating a µ-opioid receptor (MOR). Although optimal concentrations of REM can be easily maintained during surgery, it is sometimes switched to FEN for optimal pain regulation. However, standards for this switching protocol remain unclear. Opioid anesthetic efficacy is decided in part by MOR desensitization; thus, in this study, we investigated the desensitization profiles of REM and FEN to MOR. The efficacy and potency during the 1st administration of REM or FEN in activating the MOR were almost equal. Similarly, in β arrestin recruitment, which determines desensitization processes, they showed no significant differences. In contrast, the 2nd administration of FEN resulted in a stronger MOR desensitization potency than that of REM, whereas REM showed a higher internalization potency than FEN. These results suggest that different β arrestin-mediated signaling caused by FEN or REM led to their distinct desensitization and internalization processes. Our three-dimensional analysis, with in silico binding of REM and FEN to MOR models, highlighted that REM and FEN bound to similar but distinct sites of MOR and led to distinct β arrestin-mediated profiles, suggesting that distinct binding profiles to MOR may alter β arrestin activity, which accounts for MOR desensitization and internalization.

The Pain Management of Trauma Patients in the Emergency Department

The vast majority of injured patients suffer from pain. Systematic assessment of pain on admission to the emergency department (ED) is a cornerstone of translating the best treatment strategies for patient care into practice. Pain must be measured with severity scales that are validated in clinical practice, including for specific populations (such as children and older adults). Although primary care ED of trauma patients focuses on resuscitation, diagnosis and treatment, pain assessment and management remains a critical element as professionals are not prepared to provide effective and early therapy. To date, most EDs have pain assessment and management protocols that take into account the patient's hemodynamic status and clinical condition and give preference to non-pharmacological approaches where possible. When selecting medications, the focus is on those that are least disruptive to hemodynamic status. Pain relief may still be necessary in hemodynamically unstable patients, but caution should be exercised, especially when using opioids, as absorption may be impaired or shock may be exacerbated. The analgesic dose of ketamine is certainly an attractive option. Fentanyl is clearly superior to other opioids in initial resuscitation and treatment as it has minimal effects on hemodynamic status and does not cause central nervous system depression. Inhaled analgesia techniques and ultrasound-guided nerve blocks are also increasingly effective solutions. A multimodal pain approach, which involves the use of two or more drugs with different mechanisms of action, plays an important role in the relief of trauma pain. All EDs must have policies and promote the adoption of procedures that use multimodal strategies for effective pain management in all injured patients.

Opioid versus Nonopioid Analgesia for Craniotomy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Despite the use of intraoperative opioid analgesia, postoperative pain is often reported by patients undergoing craniotomies. Opioids also cause undesirable side effects in neurosurgical patients. Hence, the role of nonopioid analgesia has been explored for craniotomies in recent years.

METHODS

This systematic review evaluated evidence from randomized controlled trials (RCTs) comparing opioid and nonopioid analgesia during craniotomies regarding postoperative pain, recovery, and adverse events.

RESULTS

Of the 10,459 records obtained by searching MEDLINE, Embase, and Web of Science databases, 6 RCTs were included. No difference was observed in pain scores between opioid and nonopioid analgesia at 1 and 24 hours after surgery: mean difference (MD), 1.11 units; 95% confidence interval [CI], -0.16 to 2.38, P = 0.09 and MD, -0.06 units; 95% CI, -1.14 to 1.01, P = 0.91, respectively. The time for first postoperative analgesic requirement was shorter with opioids but was not statistically significant (MD, -84.77 minutes; 95% CI, -254.65 to 85.11; P = 0.33). Postoperative nausea and vomiting (relative risk = 1.60; 95% CI, 0.96-2.66; P = 0.07) was similar but shivering (relative risk = 2.01; 95% CI, 1.09-3.71; P = 0.03) was greater in the opioid group than nonopioid group.

CONCLUSIONS

There were no important differences in clinical outcomes between the groups in our review. The GRADE certainty of evidence was rated low for most outcomes. Available evidence does not suggest superiority of intraoperative nonopioid over opioid analgesia for postoperative pain in patients undergoing craniotomy. More studies are needed to firmly establish the role of nonopioid intraoperative analgesics as an alternative to opioids in this population.

No association of postoperative opioid usage with long-term surgery outcomes in patients with liver cancer: a population-based retrospective cohort study

ABSTRACT

Hepatocellular carcinoma (HCC) is a fatal cancer worldwide, and surgical resection remains the standard treatment. Postoperative opioid prescription has been believed to affect cancer recurrence through complex biological pathways. We conducted a retrospective cohort study using the Longitudinal Health Insurance Database of Taiwan to evaluate the relationship between postoperative opioid use and long-term surgical outcomes of patients with HCC. This study had a retrospective cohort design. In total, 812 patients older than 20 years who underwent hepatectomy because of HCC were included. The exposure group comprised patients who used opioids during hospitalization postoperatively. The comparison group included those who never used opioids during hospitalization postoperatively. A Cox proportional hazards model was used to evaluate the overall survival or recurrence-free survival rate between the opioid group and the nonopioid group. A total of 530 patients received opioids postoperatively and 282 patients did not. The hazard ratios of overall survival and recurrence-free survival were 1.10 (95% confidence interval [CI], 0.85-1.41) and 1.15 (95% CI, 0.91-1.46), respectively. Total postoperative opioids were converted into oral morphine milligram equivalents and then divided into 3 equal subgroups: low dose, <40 mg; medium dose, 40 to 144 mg; and high dose, ≥145 mg. The hazard ratios of overall survival were 0.88 (95% CI, 0.63-1.24) for the low-dose group, 1.27 (95% CI, 0.92-1.74) for the medium-dose group, and 1.14 (95% CI, 0.83-1.58) for the high-dose group. Postoperative opioids do not affect overall and recurrence-free survival in patients undergoing hepatectomy or liver transplantation because of HCC. Cancer recurrence should not be a clinical concern regarding postoperative opioid prescription.

The Impact of Peripheral Nerve Block on the Quality of Care After Ankle Fracture Surgery: A Quality Improvement Study

OBJECTIVES

To increase peripheral nerve block (PNB) administration for ankle fracture surgeries (AFSs) at our institution to above 50% by January 1st, 2021.

DESIGN

Longitudinal, single-center quality improvement study conducted at a high-volume tertiary care center.

PATIENTS

All patients undergoing isolated AFS for unimalleolar, bimalleolar, or trimalleolar ankle fracture from July 2017 to April 2021 were included in this study.

INTERVENTION

Interventions implemented to minimize barriers for PNB administration included recruitment and training of expert anesthesiologists in regional anesthesia, procurement of ultrasound machines, implementation of a dedicated block room, and creation of a pamphlet for patients describing multimodal analgesia.

MAIN OUTCOME MEASUREMENT

The primary outcome was the percentage of patients receiving PNB for AFS. Secondary outcomes included hospital length-of-stay, postanesthesia care unit (PACU) and 24-hour postoperative opioid consumption (mean oral morphine equivalent [OME]), proportion of patients not requiring opioid analgesic in PACU, and PACU and 24-hour postoperative nausea/vomiting requiring antiemetic.

RESULTS

The PNB and non-PNB groups included 78 and 157 patients, respectively. PNB administration increased from <5% to 53% after implementation of the improvement bundle. Mean PACU and 24-hour opioid analgesic consumption was lower in the PNB group (PACU OME 38.96 mg vs. 55.42 mg, P = 0.001; 24-hour OME 50.83 mg vs. 65.69 mg, P = 0.008). A greater proportion of patients in the PNB group did not require PACU opioids (62.8% vs. 27.4%, P < 0.001).

CONCLUSIONS

By performing a root cause analysis and implementing a multidisciplinary, patient-centered improvement bundle, we increased PNB administration for AFSs, resulting in reduced postoperative opioid analgesia consumption.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Analgesia nociception index and high frequency variability index: promising indicators of relative parasympathetic tone

At present, there is no objective and absolute measure of nociception, although various monitoring techniques have been developed. One such technique is the Analgesia Nociception Index (ANI), which is calculated from heart rate variability that reflects the relative parasympathetic tone. ANI is expressed on a non-unit scale of 0-100 (100 indicates maximal relative parasympathetic tone). Several studies indicated that ANI-guided anesthesia may help reduce intraoperative opioid use. The usefulness of ANI in the intensive care unit (ICU) and during surgery has also been reported. However, some limitations of ANI have also been reported; for example, ANI is affected by emotions and some drugs. In 2022, a high frequency variability index (HFVI), which was renamed from ANI and uses the same algorithm as ANI, was commercialized; therefore, ANI/HFVI are currently in the spotlight. Unlike ANI, HFVI can be displayed along with other biometric information on the Root® monitor. ANI/HFVI monitoring may affect the prognosis of not only patients in the perioperative period but those in ICU, those who receive home medical care, or outpatients. In this article, we present an updated review on ANI that has been published in the last decade, introduce HFVI, and discuss the outlooks of ANI/HFVI.

Efficacy of Dexmedetomidine vs. Remifentanil for Postoperative Analgesia and Opioid-Related Side Effects after Gynecological Laparoscopy: A Prospective Randomized Controlled Trial

Remifentanil is widely used for intraoperative analgesia, but often causes remifentanil-induced hyperalgesia (RIH) and related side effects. Dexmedetomidine, a non-opioid analgesic, has been used as an alternative to remifentanil to prevent RIH. We aimed to investigate the effect of dexmedetomidine on postoperative recovery after gynecological laparoscopy. Ninety-six adult patients undergoing elective gynecological laparoscopy were randomly assigned to the dexmedetomidine or remifentanil groups. The primary outcome was the pain score at 30 min after surgery. The secondary outcomes were intraoperative adverse events (hypotension and bradycardia) and postoperative opioid-related side effects (nausea, vomiting, requirement for rescue analgesics, and shivering). We also performed an ancillary cytokine study to evaluate oxidative stress, one of the causes of RIH. Compared with the remifentanil group, the dexmedetomidine group had lower pain scores at 30 min after surgery (4.0 ± 1.9 vs. 6.1 ± 2.0, mean ± SD, p < 0.001) and lower incidence of intraoperative hypotension and postoperative nausea, vomiting, and shivering. Furthermore, the proportion of patients requiring rescue analgesics was significantly lower in the dexmedetomidine than in the remifentanil group (25% vs. 66.7%, p < 0.001). Cytokine levels did not differ between the groups. Dexmedetomidine showed a better analgesic effect with minimal opioid-related side effects and is considered superior to remifentanil for intraoperative analgesia.