Low- versus high-dose intraoperative opioids: A systematic review with meta-analyses and trial sequential analyses

Opioid-Free Anesthesia in Bariatric Surgery: Is It the One and Only? A Comprehensive Review of the Current Literature

Opioid-free anesthesia (OFA) is a heterogeneous group of general anesthesia techniques in which the intraoperative use of opioids is eliminated. This strategy aims to decrease the risk of complications and improve the patient's safety and comfort. Such potential advantages are particularly beneficial for selected groups of patients, among them obese patients undergoing laparoscopic bariatric surgery. Opioids have been traditionally used as an element of balanced anesthesia, and replacing them requires using a combination of coanalgesics and various types of local and regional anesthesia, which also have their side effects, limitations, and potential disadvantages. Moreover, despite the growing amount of evidence, the empirical data on the superiority of OFA compared to standard anesthesia with multimodal analgesia are contradictory, and potential benefits in many studies are being questioned. Additionally, little is known about the long-term sequelae of such a strategy. Considering the above-mentioned issues, this study aims to present the potential benefits, risks, and difficulties of implementing OFA in bariatric surgery, considering the current state of knowledge and literature.

Opioid-Sparing Anesthesia Versus Opioid-Free Anesthesia for the Prevention of Postoperative Nausea and Vomiting after Laparoscopic Bariatric Surgery: A Systematic Review and Network Meta-Analysis

BACKGROUND

Patients who undergo laparoscopic bariatric surgery (LBS) are susceptible to postoperative nausea and vomiting (PONV). Opioid-free anesthesia (OFA) or opioid-sparing anesthesia (OSA) protocols have been proposed as solutions; however, differences between the 2 alternative opioid protocols for anesthesia maintenance in obese patients remain uncertain. A network meta-analysis was conducted to compare the impacts of OFA and OSA on PONV.

METHODS

Systematic searches were conducted using Embase, PubMed, MEDLINE, and Cochrane Library databases to identify randomized controlled trials (RCTs) comparing OFA and OSA strategies. After screening according to the inclusion and exclusion criteria, we used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the credibility of the evidence. The main concern of this review was the difference between OFA and OSA in reducing PONV. The primary outcome was any PONV occurrence within 24 hours. Secondary outcomes included postoperative pain intensity, opioid consumption, opioid-related adverse events, and length of hospital stay.

RESULTS

Fifteen RCTs involving 1310 patients were identified for a network meta-analysis from 1776 articles that compared OFA, OSA, and traditional opioid-based anesthesia (OBA) strategies in LBS. Twelve RCTs (80%) with 922 participants (70%) were eligible for the occurrence of PONV. These included 199 (22%) patients who received OFA and 476 (52%) and 247 (27%) patients who received OSA and OBA, respectively. OFA was more effective at reducing PONV (relative risks [RR], 0.6, 95% confidence interval [CI], 0.5-0.9, moderate-quality evidence) compared to OSA. No differences were observed in postoperative pain control or opioid consumption between the OFA and OSA strategies (very low-to high-quality evidence). Notably, OFA is associated with a higher risk of bradycardia than OSA (RR, 2.6, 95% CI, 1.2-5.9, moderate-quality evidence).

CONCLUSIONS

OFA is more effective than OSA in reducing the occurrence of PONV during the early postoperative period of LBS, although it may associate with an increased risk of bradycardia. Patients who received either opioid-alternative strategy demonstrated similar effects in reducing postoperative opioid consumption and alleviating pain intensity.

Opioid-free versus opioid-sparing anaesthesia in ambulatory total hip arthroplasty: a randomised controlled trial

BACKGROUND

Enhanced recovery after surgery pathways are essential for ambulatory surgery. They usually recommend lower intraoperative opioid use to avoid opioid-related adverse effects. This has led to opioid-sparing anaesthesia (OSA) techniques, with the extreme approach of opioid-free anaesthesia (OFA) mostly with dexmedetomidine. As evidence is lacking in day-case primary total hip arthroplasty, this study was performed to assess the potential benefits in postoperative analgesia of OFA over OSA.

METHODS

In this single-centre, prospective, triple blind study, we randomly allocated 80 patients undergoing day-case primary THA under general anaesthesia. Patients received a total intravenous anaesthesia with a laryngeal mask and multimodal analgesic regimen with non-opioid analgesics. The OSA group received low dose of sufentanil, and the OFA group received dexmedetomidine The primary outcome was the opioid consumption in the first 24 h in oral morphine equivalents (OME).

RESULTS

There was no difference in median cumulative OME consumption at 24 h between the OSA and OFA groups (12 [0-25] mg vs 16 [0-30] mg, respectively; P=0.7). Pain scores were similar and low in both groups with comparable walking recovery time. Adverse events were sparse and equivalent in both groups except for dizziness, which was more frequent in the OSA group (P<0.05).

CONCLUSIONS

In day-case total hip arthoplasty under general anaesthesia, opioid-free anaesthesia and opioid-sparing anaesthesia both provide early recovery and effective postoperative pain relief. When compared with opioid-sparing anaesthesia, opioid-free anaesthesia does not decrease opioid consumption in the first 24 h. These findings do not suggest any significant benefit from complete intraoperative avoidance of opioids.

CLINICAL TRIAL REGISTRATION

NCT0507270.

Postoperative pain after different doses of remifentanil infusion during anaesthesia: a meta-analysis

BACKGROUND

This meta-analysis aimed to explore the correlation between the different doses of remifentanil-based anaesthesia and postoperative pain in randomised trials.

METHODS

The electronic databases including PubMed, Cochrane, clinical trial registries, and Google Scholar were searched up to November 2022 for randomised controlled trials (RCTs) that assessed the dose dependent efficacy of remifentanil for postoperative pain intensity and hyperalgesia.

RESULTS

31 studies involving 2019 patients were included for analysis. Compared with the high remifentanil dose administration, patients in low doses showed less postoperative pain intensity at 1-2 h (weighted mean differences (WMD): 0.60, 95% CI, 0.05 to 1.15), 3-8 h (WMD: 0.38, 95% CI, 0.00 to 0.75), 24 h (WMD: 0.26, 95% CI, 0.04 to 0.48) and 48 h (WMD: 0.32, 95% CI, 0.09 to 0.55). Remifentanil-free regimen failed to decrease the pain score at 24 h (WMD: 0.10, 95% CI, -0.10 to 0.30) and 48 h (WMD: 0.15, 95% CI, -0.22 to 0.52) in comparison with remifentanil-based anaesthesia. After excluding trials with high heterogeneity, the dose of the remifentanil regimen was closely correlated with the postoperative pain score (P=0.03). In addition, the dose of the remifentanil regimen was not associated with the incidence of postoperative nausea and vomiting (PONV) (P=0.37).

CONCLUSIONS

Our meta-analysis reveals that the low dose of remifentanil infusion is recommendable for general anaesthesia maintenance. No evidence suggests that remifentanil-free regimen has superiority in reducing postoperative pain. Moreover, remifentanil doesn't have a dose dependent effect in initiating PONV.

TRIAL REGISTRATION

The protocol of present study was registered with PROSPERO (CRD42022378360).

Opioid infusions at different times of the day produce varying degrees of opioid-induced hyperalgesia

BACKGROUND

Opioids are metabolised by enzymes the activities of which vary with the circadian rhythm. We examined whether opioid infusions administered at different times of the day produce varying degrees of opioid-induced hyperalgesia (OIH) in animal experiments and clinical studies.

METHODS

Male Sprague-Dawley rats received remifentanil infusions (1 μg kg-1·min-1 for 1 h) at Zeitgeber times (ZT) 0, 4, 8, 12, 16, or 20 h. Rhythmicity of mechanical hypersensitivity was assayed after the infusion. Mechanical hypersensitivity, drug concentration, and metabolic enzyme activity of Wistar rats that received sufentanil (10 μg kg-1; four consecutive i.p. injections at 15-min intervals) or remifentanil infusion at ZT0 or ZT8 were assayed. Sixty patients who underwent abdominal laparoscopic surgery under general anaesthesia received remifentanil infusion (0.15 μg kg-1 min-1) and sufentanil injection (0.2 μg kg-1) at induction and skin incision, respectively. Postoperative pressure pain sensitivity, pain Numeric Rating Scale (NRS), drug concentrations, and nonspecific esterase activity were assessed.

RESULTS

Sprague-Dawley rats that received remifentanil infusion exhibited a robust rhythmic paw withdrawal threshold (JTK_CYCLE: P=0.001, Q=0.001, Phase=26). Wistar rats infused with remifentanil or sufentanil at ZT8 exhibited greater OIH (P<0.001) than those infused at ZT0, with higher blood concentrations (P<0.001) and lower metabolic enzyme activities (P=0.026 and P=0.028, respectively). Patients in the afternoon group exhibited higher pressure pain sensitivity at forearm (P=0.002), higher NRS (P<0.05), higher drug concentrations (sufentanil: P=0.037, remifentanil: P=0.005), and lower nonspecific esterase activity (P=0.024) than the morning group.

CONCLUSIONS

Opioid infusions administered at different times of day produced varying degrees of OIH, possibly related to circadian rhythms of metabolic enzyme activities.

CLINICAL TRIAL REGISTRATION

NCT05234697.

More Than a Perioperative Surgical Home: An Opportunity for Anesthesiologists to Advance Public Health

Public health and the medical specialty of anesthesiology have been closely intertwined throughout history, dating back to the 1800s when Dr. John Snow used contact tracing methods to identify the Broad Street Pump as the source of a cholera outbreak in London. During the COVID-19 pandemic, leaders in anesthesiology and anesthesia patient safety came forward to develop swift recommendations in the face of rapidly changing evidence to help protect patients and healthcare workers. While these high-profile examples may seem like uncommon events, there are many common modern-day public health issues that regularly intersect with anesthesiology and surgery. These include, but are not limited to, smoking; chronic opioid use and opioid use disorder; and obstructive sleep apnea. As an evolving medical specialty that encompasses pre- and postoperative care and acute and chronic pain management, anesthesiologists are uniquely positioned to improve patient care and outcomes and promote long-lasting behavioral changes to improve overall health. In this article, we make the case for advancing the role of the anesthesiologist beyond the original perioperative surgical home model into promoting public health initiatives within the perioperative period.

Opioid prescribing for acute postoperative pain: an overview of systematic reviews related to two consensus statements relevant at patient, prescriber, system and public health levels

BACKGROUND

National guidelines for rational opioid prescribing for acute postoperative pain are needed to optimise postoperative pain control and function whilst minimising opioid-related harm.

OBJECTIVES

This overview of systematic reviews aims to summarise and critically assess the quality of systematic reviews related to the 20 recommendations from two previously published consensus guideline papers (ten relevant at patient and prescriber levels and ten at a system / Public Health level). It also aims to identify gaps in research that require further efforts to fill these in order to augment the evidence behind creating national guidelines for rational opioid prescribing for acute postoperative pain.

METHODS

A systematic database search using PubMed/MEDLINE and Cochrane was conducted in November 2022. Furthermore, reference lists were reviewed. All identified systematic reviews were assessed for eligibility. Data from each study was extracted using a pre-standardised data extraction form. The methodological quality of the included reviews was assessed by two independent reviewers using the AMSTAR 2 checklist. Descriptive synthesis of the results was performed.

RESULTS

A total of 12 papers were eligible for analysis. Only eight out of the total 20 prioritised recommendations had systematic reviews that provided evidence related to them. These systematic reviews were most commonly of critically low quality.

CONCLUSION

The consensus papers provide guidance and recommendations based on the consensus of expert opinion that is based on the best available evidence. However, there is a lack of evidence supporting many of these consensus statements. Efforts to further analyse interventions that aim to reduce the rates of opioid prescribing and their adverse effects should therefore continue.

Perioperative opioids: a narrative review contextualising new avenues to improve prescribing

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.

Preoperative transversus abdominis plane block decreases intraoperative opiate consumption during minimally invasive cholecystectomy

BACKGROUND

The ongoing epidemic of prescription opiate abuse is one of the most pressing health issues in the United States today. Consequently, analgesic adjuncts, such as multimodal drug regimens and regional anesthetic blocks (like transversus abdominis plane (TAP) block), have been introduced to the perioperative period in hopes of decreasing postoperative opiate use. However, the effect of these interventions on intraoperative opiate use has not been examined. We hypothesized that preoperative TAP block would be associated with decreased intraoperative opiate use during minimally invasive cholecystectomy.

METHODS

This was a retrospective review of patients undergoing minimally invasive cholecystectomy between June 2018 and January 2021. Perioperative data, operative times, and medication administration data were collected. Intraoperative opiate use was calculated in total morphine equivalent doses (MED) for each patient and adjusted for operative time. Univariate analysis and multivariate linear regression were performed to determine factors affecting intraoperative opiate requirements.

RESULTS

261 patients were included in this study, of which 62 (23.8%) received preoperative TAP block and 199 (76.2%) did not. Preoperative TAP block was associated with decreased intraoperative opiate use (0.199 vs 0.312, p < 0.001), while there were no statistically significant differences associated with other analgesic adjuncts including preoperative acetaminophen (p = 0.485), celecoxib (p = 0.112), gabapentin (p = 0.165), or intraoperative ketorolac (p = 0.200). On multivariate analysis, preoperative TAP block was independently associated with decreased intraoperative opiate use (< 0.001), while chronic cholecystitis on final pathology was associated with increased intraoperative opiate use (p = 0.002).

CONCLUSION

The use of preoperative TAP block was associated with decreased intraoperative opiate use during minimally invasive cholecystectomy and should be considered for routine use. Future research should investigate whether preoperative TAP blocks and a subsequent decrease of intraoperative opiates, also result in a decrease in postoperative opiate use and improvements in postoperative outcomes.

Usefulness of Analgesia Nociception Index for guiding intraoperative opioid administration: a systematic review and meta-analysis

INTRODUCTION

This study primarily aimed at investigating the efficacy of Analgesia Nociception Index (ANI) for guiding intraoperative opioid administration in patients receiving surgery under general anesthesia.

EVIDENCE ACQUISITION

The Medline, Embase, Google scholar, and the Cochrane Library databases were searched from inception to April 2022 for randomized controlled trials. The primary outcome was intraoperative opioid administration, while the secondary outcomes included postoperative opioid consumption, pain score, emergency time, risk of nausea/vomiting (PONV), and Postanesthesia Care Unit (PACU) stay.

EVIDENCE SYNTHESIS

Six studies including 399 participants (published from 2015 to 2022) focused on non-cardiac surgery, including spine surgery (two trials), breast surgery (two trials), gynecologic surgery (one trial), and laparoscopic cholecystectomy (one trial) were included. Meta-analysis revealed no difference in intraoperative opioid administration with the use of ANI-guided analgesia compared to the control group that used conventional clinical measurements (e.g., heart rate) to guide opioid use [standardized mean difference (SMD)=-0.17, 95% CI: -0.56 to 0.22, P=0.39, I²=72%, six trials, 399 participants]. Gender-based subgroup analysis showed effectiveness of ANI for reducing opioid administration in female patients (SMD=-0.53, P=0.02). There were no differences in postoperative recovery characteristics including pain score [Mean difference (MD): -0.03, P=0.79], opioid consumption (SMD: -0.34, P=0.08), emergence time (MD=1.12, P=0.47), length of stay in the PACU (MD: -0.56, P=0.83), and risk of PONV [risk ratio(RR): 0.75, P=0.46] between the two groups.

CONCLUSIONS

Analgesia nociception index-guided analgesia was unable to reduce intraoperative opioid administration compared to monitoring using conventional clinical parameters. Further studies are required to support our findings.

Preoperative transversus abdominis plane block decreases intraoperative opiate use during pancreatoduodenectomy

BACKGROUND

Multimodal analgesia and regional anesthetic blocks, such as transversus abdominis plane (TAP) block, decrease postoperative opiate consumption but their effect on intraoperative opiates is unknown.

METHODS

This was a retrospective review of patients undergoing pancreatoduodenectomy between June 2018 and February 2021, in which perioperative data, operative times, and medication administration data were collected. Intraoperative opiate use was calculated in total morphine equivalent doses (MED) for each patient and adjusted for operative time. Univariate analysis and multivariate linear regression were performed to determine factors affecting intraoperative opiate requirements.

RESULTS

Of the 169 patients in the study, 51 (30.2%) received pre-surgical TAP blocks and 118 (69.8%) did not. There were no statistically significant differences in intraoperative opiate use with preoperative acetaminophen (p = 0.527), celecoxib (p = 0.553), gabapentin (p = 0.308), intraoperative ketorolac (p = 0.698) or epidural placement (p = 0.086). Minimally invasive surgery had lower intraoperative opiate use compared to open (p = 0.011), as well as pre-surgical TAP block compared to no pre-surgical block (5.24 vs 7.27 MED/hour, p < 0.001). On multivariate linear regression, pre-surgical TAP block (p = 0.001) was independently associated with decreased intraoperative opiate use.

CONCLUSION

Preoperative TAP blocks were associated with decreased intraoperative opiate use during pancreatoduodenectomy and should be considered for routine use.

Analgesic effects of sufentanil in combination with flurbiprofen axetil and dexmedetomidine after open gastrointestinal tumor surgery: a retrospective study

Background

To investigated the effects of sufentanil in combination with flurbiprofen axetil and dexmedetomidine for patient-controlled intravenous analgesia (PCIA) on patients after open gastrointestinal tumor surgery, and compared this combination with traditional PCIA with pure opioids or epidural analgesia (PCEA).

Methods

Patients (n = 640) who underwent open gastrointestinal tumor surgery and received patient-controlled analgesia (PCA) were included. According to the type of PCA, patients were assigned to three groups: MPCIA (PCIA with sufentanil, flurbiprofen axetil, dexmedetomidine and metoclopramide), OPCIA (PCIA with sufentanil, tramadol and metoclopramide) and PCEA group (PCEA with sufentanil and ropivacaine). The characteristics of patients, intraoperative use of analgesics, postoperative visual analogue scale (VAS), postoperative adverse reactions and postoperative recovery were collected. The primary outcome was postoperative VAS score. One-way ANOVA, Kruskal-Wallis H test, Fisher exact probability method, and binary logistic regression analysis were used for analysis.

Results

There were no significant differences in the characteristics of patients, operation time, tumor site and the use of postoperative rescue analgesics among the groups. In the first two days after open gastrointestinal tumor surgery, the VAS (expressed by median and interquartile range) of MPCIA (24^th h, resting: 1,1; movement: 3,2. 48^th h, resting: 0,1; movement: 2,1.) and PCEA (24^th h, resting: 0,1; movement: 2,1. 48^th h, resting: 0,1; movement: 2,2.) groups were significantly lower than those of OPCIA group (24^th h, resting: 2.5,2; movement: 4,2. 48^th h, resting: 1.5,1.75; movement: 3,1.) (all p <  0.01). The incidence of postoperative nausea and vomiting in MPCIA group was 13.6% on the first day after surgery, which was significantly higher than that in PCEA group. There was no significant difference in the incidence of other postoperative adverse events. Higher intraoperative sufentanil dosage (OR (95%CI) = 1.017 (1.002–1.031), p = 0.021), lower body mass index (OR (95%CI) = 2.081 (1.059–4.089), p = 0.033), and tumor location above duodenum (OR (95%CI) = 2.280 (1.445–3.596), p <  0.001) were associated with poor postoperative analgesia.

Conclusions

The analgesic effects of PCIA with sufentanil in combination with flurbiprofen axetil and dexmedetomidine on postoperative analgesia was better than that of traditional pure opioids PCIA, and similar with that of PCEA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01670-0.

System-level policies on appropriate opioid use, a multi-stakeholder consensus

BACKGROUND

This consensus statement was developed because there are concerns about the appropriate use of opioids for acute pain management, with opposing views in the literature. Consensus statement on policies for system-level interventions may help inform organisations such as management structures, government agencies and funding bodies.

METHODS

We conducted a multi-stakeholder survey using a modified Delphi methodology focusing on policies, at the system level, rather than at the prescriber or patient level. We aimed to provide consensus statements for current developments and priorities for future developments.

RESULTS

Twenty-five experts from a variety of fields with experience in acute pain management were invited to join a review panel, of whom 23 completed a modified Delphi survey of policies designed to improve the safety and quality of opioids prescribing for acute pain in the secondary care setting. Strong agreement, defined as consistent among> 75% of panellists, was observed for ten statements.

CONCLUSIONS

Using a modified Delphi study, we found agreement among a multidisciplinary panel, including patient representation, on prioritisation of policies for system-level interventions, to improve governance, pain management, patient/consumers care, safety and engagement.

Association Between Local Anesthetic Dosing, Postoperative Opioid Requirement, and Pain Scores After Lumpectomy and Sentinel Lymph Node Biopsy with Multimodal Analgesia

BACKGROUND

Multimodal analgesia (MMA) during breast surgery reduces postoperative pain and opioid requirements, but the relative contribution of local anesthetic dosing as a component of MMA is not well defined among patients undergoing lumpectomy and sentinel lymph node biopsy (SLNB).

PATIENTS AND METHODS

We identified consecutive patients who underwent lumpectomy and SLNB with MMA from 1/2019 to 4/2020. Univariable and multivariable linear and logistic regression were used to examine associations between local anesthetics, opioid requirements in the post-anesthesia care unit (PACU), and pain scores in the PACU and on postoperative day (POD) 1.

RESULTS

In total, 1603 patients [median tumor size, 14 mm (interquartile range 8-20 mm)] were included. The median PACU opioid requirement was 0 morphine milligram equivalents (interquartile range 0-5). PACU maximum pain was none or mild in 58% of patients and moderate to severe in 42%; among 420 survey respondents, 56% reported no or mild pain and 44% reported moderate to severe pain on POD 1. On multivariable analysis that adjusted for routine components of MMA, increasing doses of 0.5% bupivacaine were associated with reduced PACU opioid requirements (β -0.04, 95% confidence interval -0.07 to -0.01, p = 0.011) and lower odds of moderate to severe pain (odds ratio 0.98, 95% confidence interval 0.97-0.99, p < 0.001). Local anesthetics were not associated with pain scores on POD 1.

CONCLUSIONS

Higher amounts of local anesthetics reduce acute postoperative pain and opioid requirement after lumpectomy and SLNB. Maximizing dosing within weight-based limits is a low-risk, cost-effective pain control strategy that can be used in diverse practice settings.

Effect of dexamethasone as an analgesic adjuvant to multimodal pain treatment after total knee arthroplasty: randomised clinical trial

OBJECTIVE

To investigate the effects of one and two doses of intravenous dexamethasone in patients after total knee arthroplasty.

DESIGN

Randomised, blinded, placebo controlled trial with follow-up at 90 days.

SETTING

Five Danish hospitals, September 2018 to March 2020.

PARTICIPANTS

485 adult participants undergoing total knee arthroplasty.

INTERVENTION

A computer generated randomised sequence stratified for site was used to allocate participants to one of three groups: DX1 (dexamethasone (24 mg)+placebo); DX2 (dexamethasone (24 mg)+dexamethasone (24 mg)); or placebo (placebo+placebo). The intervention was given preoperatively and after 24 hours. Participants, investigators, and outcome assessors were blinded. All participants received paracetamol, ibuprofen, and local infiltration analgesia.

MAIN OUTCOME MEASURES

The primary outcome was total intravenous morphine consumption 0 to 48 hours postoperatively. Multiplicity adjusted threshold for statistical significance was P<0.017 and minimal important difference was 10 mg morphine. Secondary outcomes included postoperative pain.

RESULTS

485 participants were randomised: 161 to DX1, 162 to DX2, and 162 to placebo. Data from 472 participants (97.3%) were included in the primary outcome analysis. The median (interquartile range) morphine consumptions at 0-48 hours were: DX1 37.9 mg (20.7 to 56.7); DX2 35.0 mg (20.6 to 52.0); and placebo 43.0 mg (28.7 to 64.0). Hodges-Lehmann median differences between groups were: -2.7 mg (98.3% confidence interval -9.3 to 3.7), P=0.30 between DX1 and DX2; 7.8 mg (0.7 to 14.7), P=0.008 between DX1 and placebo; and 10.7 mg (4.0 to 17.3), P<0.001 between DX2 and placebo. Postoperative pain was reduced at 24 hours with one dose, and at 48 hours with two doses, of dexamethasone.

CONCLUSION

Two doses of dexamethasone reduced morphine consumption during 48 hours after total knee arthroplasty and reduced postoperative pain.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03506789.

Is Opioid-free Anesthesia Possible by Using Erector Spinae Plane Block in Spinal Surgery?

Objective: Erector spinae plane (ESP) block can be a method to be used for postoperative pain control in lumbar herniated disc operations. The aim of this study is to investigate the effect of erector spinae block in lumbar herniated disc operation on intraoperative and postoperative opioid consumption.

Methods: Sixty patients scheduled for lumbar herniated disc surgery were included in the study. Patients were randomized into two groups: ESP block and control. Ultrasound-guided ESP block with 20 ml 0.25% bupivacaine at the bilateral L3 vertebral level was applied preoperatively to all patients in the ESP group. Patients in both groups were provided with intravenous patient-controlled analgesia (PCA) device containing fentanyl for postoperative analgesia. Fentanyl consumption and visual analogue scale (VAS) score were recorded at 15 min, 1, 6, 12, and 24 hours postoperatively.

Results: Fentanyl consumption (group C: 59.3 ± 20.66, group E: 41.3 ± 21.61, p: 0,02) and VAS score (group C: VASm 4 (2-4), group E: 2 (2-4), p: 0.009) decreased with ESP block application at postoperative one hour. No difference was detected between the two groups in terms of fentanyl consumption and VAS score at 6, 12, and 24 hours postoperatively (p>0.05). The intraoperative heart rate of patients in the ESP group was lower than the control group (p<0.05).

Conclusion: ESP block decreases opioid consumption and VAS score at postoperative one hour in patients, and also patients who receive ESP block do not require intraoperative opioid administration.

Combination of femoral triangle block and infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) versus local infiltration analgesia for analgesia after anterior cruciate ligament reconstruction: a randomized controlled triple-blinded trial

BACKGROUND AND OBJECTIVES

Femoral triangle block and local infiltration analgesia are two effective analgesic techniques after anterior cruciate ligament reconstruction. Recently, the iPACK block (infiltration between the popliteal artery and the capsule of the posterior knee) has been described to relieve posterior knee pain. This randomized controlled triple-blinded trial tested the hypothesis that the combination of femoral triangle block and iPACK provides superior analgesia to local infiltration analgesia after anterior cruciate ligament reconstruction.

METHODS

Sixty patients undergoing anterior cruciate ligament reconstruction received general anesthesia and were randomly allocated to two groups: femoral triangle block and iPACK under ultrasound guidance or local infiltration analgesia. For each group, a total of 160 mg of ropivacaine was injected. Postoperative pain treatment followed a predefined protocol with intravenous morphine patient-controlled analgesia, acetaminophen, and ibuprofen. The primary outcome was cumulative intravenous morphine consumption at 24 hours postoperatively. Secondary pain-related outcomes included pain scores (Numeric Rating Scale out of 10) measured at 2 and 24 hours postoperatively. Functional outcomes, such as range of motion and quadriceps strength, were also recorded at 24 postoperative hours, and at 4 and 8 postoperative months.

RESULTS

Cumulative intravenous morphine consumption at 24 hours postoperatively was significantly reduced in the femoral triangle block and iPACK group (femoral triangle block and iPACK: 9.7 mg (95% CI: 6.7 to 12.7); local infiltration analgesia: 17.0 mg (95% CI: 11.1 to 23.0), p=0.03). Other pain-related and functional-related outcomes were similar between groups.

CONCLUSIONS

The combination of femoral triangle block and iPACK reduces intravenous morphine consumption during the first 24 hours after anterior cruciate ligament reconstruction, when compared with local infiltration analgesia, without effect on other pain-related, early, or late functional-related outcomes.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03680716).

Opioid-Free Anesthesia Benefit-Risk Balance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Opioid-free anesthesia (OFA) is used in surgery to avoid opioid-related side effects. However, uncertainty exists in the balance between OFA benefits and risks. We searched for randomized controlled trials (RCTs) comparing OFA to opioid-based anesthesia (OBA) in five international databases. The co-primary outcomes were postoperative acute pain and morphine consumption at 2, 24, and 48 h. The secondary outcomes were the incidence of postoperative chronic pain, hemodynamic tolerance, severe adverse effects, opioid-related adverse effects, and specific adverse effects related to substitution drugs. Overall, 33 RCTs including 2209 participants were assessed. At 2 h, the OFA groups had lower pain scores at rest MD (0.75 (−1.18; −0.32)), which did not definitively reach MCID. Less morphine was required in the OFA groups at 2 and 24 h, but with very small reductions: 1.61 mg (−2.69; −0.53) and −1.73 mg (p < 0.05), respectively, both not reaching MCID. The reduction in PONV in the OFA group in the PACU presented an RR of 0.46 (0.38, 0.56) and an RR of 0.34 (0.21; 0.56), respectively. Less sedation and shivering were observed in the OFA groups with an SMD of −0.81 (−1.05; −0.58) and an RR of 0.48 (0.33; 0.70), respectively. Quantitative analysis did not reveal differences between the hemodynamic outcomes, although severe side effects have been identified in the literature. No clinically significant benefits were observed with OFA in terms of pain and opioid use after surgery. A clear benefit of OFA use was observed with respect to a reduction in PONV. However, more data on the safe use of OFAs should be collected and caution should be taken in the development of OFA.

Persistent postoperative opioid use in Europe: A systematic review

BACKGROUND

In the United States, postoperative opioid prescriptions have been implicated in the so-called 'opioid epidemic'. In Europe, the extent of overprescribing or misuse of opioids is not known.

OBJECTIVES

To describe the proportion of persistent postoperative opioid use in adults (>18 years) in European countries.

DESIGN

Systematic review of the published data.

DATA SOURCES

We searched the electronic literature databases MEDLINE (Ovid), Embase (Ovid), PubMed/MEDLINE and Scopus.

ELIGIBILITY CRITERIA

Studies describing opioid use in adult patients (>18 years) at least 3 months after surgery.

RESULTS

One thousand three hundred and seven studies were found, and 12 studies were included in this review. The rate of opioid use after 3 to 6 months was extracted from the studies and categorised by the type of surgery. Nine studies investigated opioid use after total hip or total knee arthroplasties (THA and TKA) and reported opioid user rates between 7.9 and 41% after 3 months. In all the included studies, a proportion between 2 and 41% of patients were opioid users 3 months after surgery. The level of evidence varied from high to very low.

CONCLUSION

To describe persistent opioid use in relation to specific countries or types of surgery is not possible. Because of the wide ranges observed, we can neither confirm nor rule out a possible public health problem linked to the persistent use of opioids in Europe.

STUDY REGISTRATION

PROSPERO: CRD42019154292.

Mechanisms, diagnosis, prevention and management of perioperative opioid-induced hyperalgesia

Opioid-induced hyperalgesia (OIH) occurs when opioids paradoxically enhance the pain they are prescribed to ameliorate. To address a lack of perioperative awareness, we present an educational review of clinically relevant aspects of the disorder. Although the mechanisms of OIH are thought to primarily involve medullary descending pathways, it is likely multifactorial with several relevant therapeutic targets. We provide a suggested clinical definition and directions for clinical differentiation of OIH from other diagnoses, as this may be confusing but is germane to appropriate management. Finally, we discuss prevention including patient education and analgesic management choices. As prevention may serve as the best treatment, patient risk factors, opioid mitigation, and both pharmacologic and non-pharmacologic strategies are discussed.

Procedure-specific and patient-specific pain management for ambulatory surgery with emphasis on the opioid crisis

PURPOSE OF REVIEW

Postoperative pain is frequent while, on the other hand, there is a grooving general concern on using effective opioid pain killers in view of the opioid crisis and significant incidence of opioid abuse. The present review aims at describing nonopioid measures in order to optimize and tailor perioperative pain management in ambulatory surgery.

RECENT FINDINGS

Postoperative pain should be addressed both preoperatively, intraoperatively and postoperatively. The management should basically be multimodal, nonopioid and procedure-specific. Opioids should only be used when needed on top of multimodal nonopioid prophylaxis, and then limited to a few days at maximum, unless strict control is applied. The individual patient should be screened preoperatively for any risk factors for severe postoperative pain and/or any abuse potential.

SUMMARY

Basic multimodal analgesia should start preoperatively or peroperatively and include paracetamol, cyclo-oxygenase (COX)-2 specific inhibitor or conventional nonsteroidal anti-inflammatory drug (NSAID) and in most cases dexamethasone and local anaesthetic wound infiltration. If any of these basic analgesics are contraindicated or there is an extra risk of severe postoperative pain, further measures may be considered: nerve-blocks or interfascial plane blocks, gabapentinnoids, clonidine, intravenous lidocaine infusion or ketamine infusion. In the abuse-prone patient, a preferably nonopioid perioperative approach should be aimed at.