Perioperative Opioids, the Opioid Crisis, and the Anesthesiologist

Effects of liposomal bupivacaine on opioid use and healthcare resource utilization after outpatient spine surgery: a real-world assessment

BACKGROUND CONTEXT

Perioperative pain management affects cost and outcomes in elective spine surgery.

PURPOSE

This study investigated the association between liposomal bupivacaine (LB) and outpatient spine surgery outcomes, including perioperative, postoperative, and postdischarge opioid use and healthcare resource utilization.

STUDY DESIGN

This was a retrospective comparative study.

PATIENT SAMPLE

Eligibility criteria included adults with ≥6 months of continuous data before and after outpatient spine procedures including discectomy, laminectomy, or lumbar fusion. Patients receiving LB were matched 1:3 to patients receiving non-LB analgesia by propensity scores.

OUTCOME MEASURES

Outcomes included (1) opioid use in morphine milligram equivalents (MMEs) during the perioperative and postdischarge periods and (2) postdischarge readmission and emergency department (ED) visits up to 3 months after surgery. Generalized linear mixed-effects modeling with appropriate distributions was used for analysis.

METHODS

Deidentified data from the IQVIA linkage claims databases (2016-2019) were used for the analysis. This study was funded by Pacira BioSciences, Inc.

RESULTS

In total, 381 patients received LB and 1143 patients received non-LB analgesia. Baseline characteristics were well balanced after propensity score matching. The LB cohort used fewer MMEs versus the non-LB cohort before discharge (80 vs 132 MMEs [mean difference, -52 MMEs; p=.0041]). Following discharge, there was a nonsignificant reduction in opioid use in the LB cohort versus the non-LB cohort within 90 days (429 vs 480 MMEs [mean difference, -50 MMEs; p=.289]) and from >90 days to 180 days (349 vs 381 MMEs [mean difference, -31 MMEs; p=.507]). The LB cohort had significantly lower rates of ED visits at 2 months after discharge versus the non-LB cohort (3.9% vs 7.6% [odds ratio, 0.50; p=.015]). Postdischarge readmission rates did not differ between cohorts.

CONCLUSIONS

Use of LB for outpatient spine surgery was associated with reduced opioid use at the hospital and nonsignificant reduction in opioid use at all postoperative timepoints examined through 90 days after surgery versus non-LB analgesia. ED visit rates were significantly lower at 60 days after discharge. These findings support reduced cost and improved quality metrics in patients treated with LB versus non-LB analgesia for outpatient spine surgery.

A pilot multicentre randomised clinical trial to determine the effect of a pharmacist-partnered opioid tapering intervention before total hip or knee arthroplasty

BACKGROUND

Opioid analgesic use before total hip or knee arthroplasty has been associated with worse postoperative outcomes. This pilot study aimed to examine the feasibility of a telehealth-based pharmacist-partnered opioid tapering intervention before elective primary hip or knee arthroplasty and its potential effectiveness compared with usual care.

METHODS

This study was conducted at seven hospitals in New South Wales, Australia. Eligible patients were those aged ≥ 18 years, scheduled to undergo primary hip or knee arthroplasty for osteoarthritis and taking opioid analgesics pre-operatively. The intervention group participated in an opioid tapering telehealth service, a partnership between a pharmacist and general practitioner, for 3 months pre-operatively up to the day of surgery, while the control group received usual care. The primary outcomes of the study were to investigate the feasibility of the intervention (i.e. adherence to treatment) and potential effectiveness in decreasing baseline daily opioid dose by > 50% before surgery.

RESULTS

Between December 2021 and June 2023, 70 patients were recruited and assigned randomly to the intervention group (n = 35) or control group (n = 35). Baseline characteristics were similar between groups. Thirty patients in each group completed their allocated treatment. All patients allocated to the intervention group completed at least one appointment with a pharmacist, with the median (IQR [range]) being 2 (1-4 [1-6]) appointments. The number of patients who successfully decreased their baseline daily opioid dose by ≥ 50% before surgery was 27/30 in the intervention group compared with 5/30 in the usual care group (p < 0.001).

CONCLUSIONS

The findings of this pilot study support the feasibility of a telehealth-delivered, pharmacist-partnered opioid tapering service for patients scheduled for primary hip or knee arthroplasty. A broader multicentre study to examine the effectiveness of this intervention on clinical outcomes is warranted.

Opioid-free anaesthesia with dexmedetomidine and lidocaine versus remifentanil-based anaesthesia in cardiac surgery: study protocol of a French randomised, multicentre and single-blinded OFACS trial

INTRODUCTION

Intraoperative opioids have been used for decades to reduce negative responses to nociception. However, opioids may have several, and sometimes serious, adverse effects. Cardiac surgery exposes patients to a high risk of postoperative complications, some of which are common to those caused by opioids: acute respiratory failure, postoperative cognitive dysfunction, postoperative ileus (POI) or death. An opioid-free anaesthesia (OFA) strategy, based on the use of dexmedetomidine and lidocaine, may limit these adverse effects, but no randomised trials on this issue have been published in cardiac surgery.We hypothesised that OFA versus opioid-based anaesthesia (OBA) may reduce the incidence of major opioid-related complications after cardiac surgery.

METHODS AND ANALYSIS

Multicentre, randomised, parallel and single-blinded clinical trial in four cardiac surgical centres in France, including 268 patients scheduled for coronary artery bypass grafting under cardiac bypass, with or without aortic valve replacement. Patients will be randomised to either a control OBA protocol using remifentanil or an OFA protocol using dexmedetomidine/lidocaine. The primary composite endpoint is the occurrence of at least one of the following: (1) postoperative cognitive disorder evaluated by the Confusion Assessment Method for the Intensive Care Unit test, (2) POI, (3) acute respiratory distress or (4) death within the first 48 postoperative hours. Secondary endpoints are postoperative pain, morphine consumption, nausea-vomiting, shock, acute kidney injury, atrioventricular block, pneumonia and length of hospital stay.

ETHICS AND DISSEMINATION

This trial has been approved by an independent ethics committee (Comité de Protection des Personnes Ouest III-Angers on 23 February 2021). Results will be submitted in international journals for peer reviewing.

TRIAL REGISTRATION NUMBER

NCT04940689, EudraCT 2020-002126-90.

[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.

Public Health Informatics and the Perioperative Physician: Looking to the Future

The role of informatics in public health has increased over the past few decades, and the coronavirus disease 2019 (COVID-19) pandemic has underscored the critical importance of aggregated, multicenter, high-quality, near-real-time data to inform decision-making by physicians, hospital systems, and governments. Given the impact of the pandemic on perioperative and critical care services (eg, elective procedure delays; information sharing related to interventions in critically ill patients; regional bed-management under crisis conditions), anesthesiologists must recognize and advocate for improved informatic frameworks in their local environments. Most anesthesiologists receive little formal training in public health informatics (PHI) during clinical residency or through continuing medical education. The COVID-19 pandemic demonstrated that this knowledge gap represents a missed opportunity for our specialty to participate in informatics-related, public health-oriented clinical care and policy decision-making. This article briefly outlines the background of PHI, its relevance to perioperative care, and conceives intersections with PHI that could evolve over the next quarter century.

Opioids in advanced cancer: use, storage and disposal in the home

OBJECTIVES

To determine the patterns of storing, using and disposing of opioids among patients with advanced cancer followed at home.

METHODS

Patients who were prescribed opioids were selected. Prescribed opioids and their doses used for background pain and breakthrough pain were collected, as well as CAGE (cut down, annoyed, guilty and eye opener) for alcohol and drugs, smoking and history of illicit substance use. Questions regarding the opioid use, storage and disposal were posed.

RESULTS

100 patients were surveyed. Fifty-one patients had unused opioids at home, 25 patients did not throw away the drugs, 40 patients saved opioids for future use and 35 patients were unaware of proper opioid disposal methods. A total of 28 patients reported unsafe use by sharing or losing their opioids; 12 patients were unaware that their opioid could be fatal when taken by others. Most patients acknowledged that pain medications could be dangerous when taken by others. Patients with a partner and who were married were more likely to keep their opioids locked (p=0.028 and p=0.025, respectively).

CONCLUSION

A large number of patients with advanced cancer followed at home do not store, use and dispose of opioids safely. Patient education programmes should be incorporated to decrease the availability of opioids at home for abuse, diversion, and accidental poisoning.

Postoperative Opioid Prescribing in Adolescents and Young Adults After Urologic Procedures Is Associated With New Persistent Opioid Use Disorder: A Large Claims Database Analysis

OBJECTIVE

To assess the risk of persistent opioid use following various urologic procedures in adolescents and young adults.

MATERIALS AND METHODS

The TriNetX LLC Diamond Network was queried for patients aged 13-21years who underwent pyeloplasty, hypospadias repair, inguinal hernia repair, inguinal orchiopexy, hydrocelectomy, or circumcision. Cohorts of patients prescribed and not prescribed postoperative opioids were created and propensity-matched for age, race/ethnicity, psychiatric diagnoses, and preoperative pain diagnoses. The primary outcome was new persistent opioid use, defined as new opioid use 3-9months after index procedure without another surgery requiring anesthesia during the postoperative timeframe.

RESULTS

Of 32,789 patients identified, 66.0% received a postoperative opioid prescription. After propensity score matching for each procedure, 18,416 patients were included: 197 for pyeloplasty, 469 for hypospadias repair, 1818 for inguinal hernia repair, 2664 for inguinal orchiopexy, 534 for hydrocelectomy, and 3526 for circumcision. Overall, 0.41% of patients who did not receive postoperative opioids developed new persistent opioid use, whereas 1.69% of patients who received postoperative opioids developed new persistent opioid use (P < .05). Patients prescribed postoperative opioids had statistically higher odds of developing new persistent opioid use for hypospadias repair (RR: 17.0; 95% CI: 2.27-127.2), inguinal orchiopexy (RR: 3.46; 95% CI: 1.87-6.4), inguinal hernia repair (RR: 2.18; 95% CI: 1.07-4.44), and circumcision (RR: 4.83; 95% CI: 2.60-8.98).

CONCLUSION

The use of postoperative opioids after urological procedures in adolescents and young adults is associated with a significant risk of developing new persistent opioid use.

Continuous Serratus - Intercostal Plane Block for Perioperative Analgesia in Upper Abdominal Surgeries: A Prospective Randomized Controlled Study

Objective

Acute pain management after open abdominal surgeries is an essential goal in perioperative management.. Recently, serratus-intercostal plane block (SIPB) was suggested as an analgesic technique for upper abdominal surgeries.

Methods

This prospective, randomized, controlled study included sixty adult patients scheduled for open upper abdominal surgeries. Patients were allocated into two equal groups: SIPB group (S group, n = 30) and control group (the C group, n = 30). In the S group, SIPB was performed in the midaxillary line at the eighth rib level followed by continuous infusion of local anaesthetic for the first postoperative day. In the C group, no block was done. The primary objective of the study was to control postoperative pain on the first postoperative day as assessed by the numerical rating scale (NRS). Secondary outcomes included perioperative hemodynamics, total postoperative analgesic consumption, number of analgesic requests, and incidence of postoperative nausea and vomiting.

Results

The mean postoperative NRS reported in group S was statistically lower than that in group C (2.4±0.7, 3.9±0.31, P < 0.001). The postoperative morphine consumption was lower in the S group than in the C group [(0 (0-4), 3 (1-4), respectively, P < 0.001]. The incidence of PONV was significantly lower in the S group than in the C group (16.7% and 40%, P < 0.045).

Conclusion

SIPB was associated with a better analgesic profile compared with the control group after upper abdominal surgeries. Further studies are recommended to determine block safety in special patient groups, including bariatric and laparoscopic surgeries.

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

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.

Caring for Our Patients With Opioid Use Disorder in the Perioperative Period: A Guide for the Anesthesiologist

Opioid use disorder (OUD) is a rising public health crisis, impacting millions of individuals and families worldwide. Anesthesiologists can play a key role in improving morbidity and mortality around the time of surgery by informing perioperative teams and guiding evidence-based care and access to life-saving treatment for patients with active OUD or in recovery. This article serves as an educational resource for the anesthesiologist caring for patients with OUD and is the second in a series of articles published in Anesthesia & Analgesia on the anesthetic and analgesic management of patients with substance use disorders. The article is divided into 4 sections: (1) background to OUD, treatment principles, and the anesthesiologist; (2) perioperative considerations for patients prescribed medications for OUD (MOUD); (3) perioperative considerations for patients with active, untreated OUD; and (4) nonopioid and nonpharmacologic principles of multimodal perioperative pain management for patients with untreated, active OUD, or in recovery. The article concludes with a stepwise approach for the anesthesiologist to support OUD treatment and recovery. The anesthesiologist is an important leader of the perioperative team to promote these suggested best practices and help save lives.

Evidence-Based Opioid Prescribing Guidelines and New Persistent Opioid Use After Surgery

OBJECTIVE

Evaluate the association of evidence-based opioid prescribing guidelines with new persistent opioid use after surgery.

SUMMARY BACKGROUND DATA

Patients exposed to opioids after surgery are at risk of new persistent opioid use, which is associated with opioid use disorder and overdose. It is unknown whether evidence-based opioid prescribing guidelines mitigate this risk.

METHODS

Using Medicare claims, we performed a difference-in-differences study of opioid-naive patients who underwent 1 of 6 common surgical procedures for which evidence-based postoperative opioid prescribing guidelines were released and disseminated through a statewide quality collaborative in Michigan in October 2017. The primary outcome was the incidence of new persistent opioid use, and the secondary outcome was total postoperative opioid prescription quantity in oral morphine equivalents (OME).

RESULTS

We identified 24,908 patients who underwent surgery in Michigan and 118,665 patients who underwent surgery outside of Michigan. Following the release of prescribing guidelines in Michigan, the adjusted incidence of new persistent opioid use decreased from 3.29% (95% CI 3.15-3.43%) to 2.51% (95% CI 2.35-2.67%) in Michigan, which was an additional 0.53 (95% CI 0.36-0.69) percentage point decrease compared with patients outside of Michigan. Simultaneously, adjusted opioid prescription quantity decreased from 199.5 (95% CI 198.3-200.6) mg OME to 88.6 (95% CI 78.7-98.5) mg OME in Michigan, which was an additional 55.7 (95% CI 46.5-65.4) mg OME decrease compared with patients outside of Michigan.

CONCLUSIONS

Evidence-based opioid prescribing guidelines were associated with a significant reduction in the incidence of new persistent opioid use and the quantity of opioids prescribed after surgery.

Best Practice Alerts Informed by Inpatient Opioid Intake to Reduce Opioid Prescribing after Surgery (PRIOR): A Cluster Randomized Multiple Crossover Trial

BACKGROUND

Overprescription of opioids after surgery remains common. Residual and unnecessarily prescribed opioids can provide a reservoir for nonmedical use. This study therefore tested the hypothesis that a decision-support tool embedded in electronic health records guides clinicians to prescribe fewer opioids at discharge after inpatient surgery.

METHODS

This study included 21,689 surgical inpatient discharges in a cluster randomized multiple crossover trial from July 2020 to June 2021 in four Colorado hospitals. Hospital-level clusters were randomized to alternating 8-week periods during which an electronic decision-support tool recommended tailored discharge opioid prescriptions based on previous inpatient opioid intake. During active alert periods, the alert was displayed to clinicians when the proposed opioid prescription exceeded recommended amounts. No alerts were displayed during inactive periods. Carryover effects were mitigated by including 4-week washout periods. The primary outcome was oral morphine milligram equivalents prescribed at discharge. Secondary outcomes included combination opioid and nonopioid prescriptions and additional opioid prescriptions until day 28 after discharge. A vigorous state-wide opioid education and awareness campaign was in place during the trial.

RESULTS

The total postdischarge opioid prescription was a median [quartile 1, quartile 3] of 75 [0, 225] oral morphine milligram equivalents among 11,003 patients discharged when the alerts were active and 100 [0, 225] morphine milligram equivalents in 10,686 patients when the alerts were inactive, with an estimated ratio of geometric means of 0.95 (95% CI, 0.80 to 1.13; P = 0.586). The alert was displayed in 28% (3,074 of 11,003) of the discharges during the active alert period. There was no relationship between the alert and prescribed opioid and nonopioid combination medications or additional opioid prescriptions written after discharge.

CONCLUSIONS

A decision-support tool incorporated into electronic medical records did not reduce discharge opioid prescribing for postoperative patients in the context of vigorous opioid education and awareness efforts. Opioid prescribing alerts might yet be valuable in other contexts.(Anesthesiology 2023; 139:186-96).

EDITOR’S PERSPECTIVE

Substance Use Disorders in Adolescents and Young Adults: History and Perioperative Considerations From the Society for Pediatric Pain Medicine

Substance use disorders (SUDs) are on the rise in children and young adults in the United States. According to reports, over 40 million people aged 12 and older had a diagnosed SUD in 2020.1 A recent report from the Centers for Disease Control and Prevention (CDC) found that overdose death in children aged 10 to 19 years old increased 109% from 2019 to 2021.2 Given the rapidly increasing prevalence of SUD, anesthesiologists will almost certainly encounter children, adolescents, and young adults with a history of recreational drug use or nonmedical use of prescription opioids in the perioperative period. Since the perioperative period can be a particularly challenging time for patients with SUD, anesthesiologists can tailor their perioperative care to reduce rates of relapse and can serve as both advocates and educators for this vulnerable patient population. This article examines the history of SUD and physiology of substance use in children, adolescents, and young adults, including reasons why young people are more susceptible to the addictive effects of many substances. The coronavirus disease 2019 (COVID-19) pandemic impacted many aspects of life, including increased social isolation and shifted dynamics at home, both thought to impact substance use.3 Substance use patterns in the wake of the COVID-19 pandemic are explored. Although current literature is mostly on adults, the evidence-based medical treatments for patients with SUD are reviewed, and recommendations for perioperative considerations are suggested. The emphasis of this review is on opioid use disorder, cannabis, and vaping particularly because these have disproportionately affected the younger population. The article provides recommendations and resources for recognizing and treating adolescents and young adults at risk for SUD in the perioperative period. It also provides suggestions to reduce new persistent postoperative opioid use.

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.

Mechanisms of Neurorespiratory Toxicity Induced by Fentanyl Analogs—Lessons from Animal Studies

In 2020, fentanyl and its analogs contributed to ~65% of drug-attributed fatalities in the USA, with a threatening increasing trend during the last ten years. These synthetic opioids used as potent analgesics in human and veterinary medicine have been diverted to recreational aims, illegally produced and sold. Like all opioids, central nervous system depression resulting from overdose or misuse of fentanyl analogs is characterized clinically by the onset of consciousness impairment, pinpoint miosis and bradypnea. However, contrasting with what observed with most opioids, thoracic rigidity may occur rapidly with fentanyl analogs, contributing to increasing the risk of death in the absence of immediate life support. Various mechanisms have been proposed to explain this particularity associated with fentanyl analogs, including the activation of noradrenergic and glutamatergic coerulospinal neurons and dopaminergic basal ganglia neurons. Due to the high affinities to the mu-opioid receptor, the need for more elevated naloxone doses than usually required in morphine overdose to reverse the neurorespiratory depression induced by fentanyl analogs has been questioned. This review on the neurorespiratory toxicity of fentanyl and analogs highlights the need for specific research focused on these agents to better understand the involved mechanisms of toxicity and develop dedicated strategies to limit the resulting fatalities.

A Neural Network Model Using Pain Score Patterns to Predict the Need for Outpatient Opioid Refills Following Ambulatory Surgery: Algorithm Development and Validation

BACKGROUND

Expansion of clinical guidance tools is crucial to identify patients at risk of requiring an opioid refill after outpatient surgery.

OBJECTIVE

The objective of this study was to develop machine learning algorithms incorporating pain and opioid features to predict the need for outpatient opioid refills following ambulatory surgery.

METHODS

Neural networks, regression, random forest, and a support vector machine were used to evaluate the data set. For each model, oversampling and undersampling techniques were implemented to balance the data set. Hyperparameter tuning based on k-fold cross-validation was performed, and feature importance was ranked based on a Shapley Additive Explanations (SHAP) explainer model. To assess performance, we calculated the average area under the receiver operating characteristics curve (AUC), F1-score, sensitivity, and specificity for each model.

RESULTS

There were 1333 patients, of whom 144 (10.8%) refilled their opioid prescription within 2 weeks after outpatient surgery. The average AUC calculated from k-fold cross-validation was 0.71 for the neural network model. When the model was validated on the test set, the AUC was 0.75. The features with the highest impact on model output were performance of a regional nerve block, postanesthesia care unit maximum pain score, postanesthesia care unit median pain score, active smoking history, and total perioperative opioid consumption.

CONCLUSIONS

Applying machine learning algorithms allows providers to better predict outcomes that require specialized health care resources such as transitional pain clinics. This model can aid as a clinical decision support for early identification of at-risk patients who may benefit from transitional pain clinic care perioperatively in ambulatory surgery.

A narrative review on the non-surgical treatment of chronic postoperative inguinal pain: a challenge for both surgeon and anaesthesiologist

INTRODUCTION

Chronic pain is one of the most frequent clinical problems after inguinal hernia surgery. Despite more than two decades of research and numerous publications, no evidence exists to allow for chronic postoperative inguinal pain (CPIP) specific treatment algorithms.

METHODS

This narrative review presents the current knowledge of the non-surgical management of CPIP and makes suggestions for daily practice.

RESULTS

There is a paucity for high-level evidence of non-surgical options for CPIP. Different treatment options and algorithms have been published for chronic pain patients in the last decades.

DISCUSSION AND CONCLUSION

It is suggested that non-surgical treatment is introduced in the management of all CPIP patients. The overall approach to interventions should be pragmatic, tiered and multi-interventional, starting with least invasive and only moving to more invasive procedures upon lack of effect. Evaluation should be multidisciplinary and should take place in specialized centres. We strongly suggest to follow general guidelines for treatment of persistent pain and to build a database allowing for establishing CPIP specific evidence for optimal analgesic treatments.

Efficacy of pericapsular nerve group (PENG) block on perioperative pain management in elderly patients undergoing hip surgical procedures: a protocol for a systematic review with meta-analysis and trial sequential analysis

INTRODUCTION

An increasing number of elderly patients suffer from hip diseases associated with moderate to severe perioperative pain during the accelerating global ageing process. Optimal analgesia can decrease perioperative complications and facilitate elderly patients' perioperative recovery. Pericapsular nerve group (PENG) block is a relatively new, analgesia adequate and motor-sparing block technique for perioperative pain management of hip diseases. However, the efficacy of PENG block remains unclear as the limited clinical evidence. Then, we will perform a protocol for a systematic review and meta-analysis to identify the efficacy of PENG block for perioperative pain management.

METHODS AND ANALYSIS

PubMed, Ovid Medline, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, Chinese BioMedical Literature, Wanfang and VIP databases will be searched from inception to August 2022 to identify randomised controlled trials of elderly patients accepting PENG block for hip diseases. The primary outcome will be the pain intensity after pain management. Secondary outcomes will be quadriceps strength, perioperative rescue analgesia information and perioperative complications. Assessment of heterogeneity will be primarily inspected by forest plots. If there is no indication of funnel plot asymmetry, a random-effects meta-analysis will be performed. The Cochrane risk-of-bias tool, Grading of Recommendations Assessment, Development and Evaluation and trial sequential analysis will be conducted to evaluate the evidence quality and control the random errors. Funnel plots and Egger's regression test will be performed to evaluate publication bias.

ETHICS AND DISSEMINATION

Ethical approval was not required for this systematic review protocol. The results will be disseminated through peer-reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42022313895.

Association Between Initial Prescription Size and Likelihood of Opioid Refill After Total Knee and Hip Arthroplasty

BACKGROUND

The present study was designed to test the hypothesis that there was no association between initial opioid prescription size and the likelihood of refill after elective primary total knee (TKA) and hip arthroplasty (THA).

METHODS

We retrospectively analyzed large national datasets of commercial and Medicare insurance claims to identify a weighted cohort of 120,889 primary total joint arthroplasties (76,900 TKA and 43,989 THA) comprised of opioid-naive patients aged 18 to 75 years who had surgery between January 2015 and November 2019. The primary outcome was refill of any prescription opioid medication within 30 days after discharge, and the primary predictor variable was the total amount of opioid filled in the initial discharge prescription measured in oral morphine equivalents (OMEs). Logistic regressions were used to estimate the likelihood of refill, given a particular prescription size while adjusting for multiple patient factors, including age, sex, comorbidities, and year of surgery.

RESULTS

The 30-day refill rate was 59.6% following TKA and 26.1% for THA. Adjusted odds of refill decreased by 2% for every 75 OME (10 tablets of 5 mg oxycodone) increase to the initial prescription size among the THA cohort (adjusted odds ratio [OR] = 0.98; 95% CI 0.97-0.99), and decreased by 3% for the TKA cohort (aOR = 0.97; 95% CI 0.97-0.98).

CONCLUSION

These nationally representative data demonstrated that larger initial opioid prescription size was associated with small but clinically insignificant decreases in 30-day refill after total joint arthroplasty. This finding should allay concerns about efforts to decrease postsurgical opioid prescribing.