The perioperative combination of methadone and ketamine reduces post-operative opioid usage compared with methadone alone

Perioperative Methadone for Spine Surgery: A Scoping Review

Complex spine surgery is associated with significant acute postoperative pain. Methadone possesses pharmacological properties that make it an attractive analgesic modality for major surgeries. This scoping review aimed to summarize the evidence for the perioperative use of methadone in adults undergoing complex spine surgery. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). A search was performed using MEDLINE, CINAHL, Cochrane Library, Scopus, Embase, and Joanna Briggs between January 1946 and April 2023. The initial search identified 317 citations, of which 12 met the criteria for inclusion in the review. There was significant heterogeneity in the doses, routes of administration, and timing of perioperative methadone administration in the included studies. On the basis of the available literature, methadone has been associated with reduced postoperative pain scores and reduced postoperative opioid consumption. Though safety concerns have been raised by observational studies, these have not been confirmed by prospective randomized studies. Further research is required to explore optimal methadone dosing regimens, the potential synergistic relationships between methadone and other pharmacological adjuncts, as well as the potential long-term antinociceptive benefits of perioperative methadone administration.

Intraoperative Methadone in Spine Surgery ERAS Protocols: A Systematic Review of the Literature

STUDY DESIGN

Systematic review.

OBJECTIVE

To systematically review the use of intraoperative methadone in spine surgery and examine its effects on postoperative opioid use, pain, length of stay, and operative time.

SUMMARY OF BACKGROUND DATA

Spine surgery patients commonly have a history of chronic pain and opioid use, and as a result, they are at an increased risk of severe postoperative pain. While pure mu opioids remain the standard for acute surgical pain management, they are associated with significant short-term and long-term adverse events. Methadone presents an alternative to pure mu opioids which may improve postoperative management of pain following intraoperative use.

METHODS

A systematic review of MEDLINE, Embase, and Web of Science databases was conducted to review existing literature detailing operating time, postoperative pain, opioid usage, and hospital length of stay (LOS) following intraoperative methadone administration in spine surgery.

RESULTS

Following screening of 994 articles and application of inclusion criteria, 8 articles were included, 4 of which were retrospective. Conventional spine surgery intraoperative analgesic strategies used as comparators for intraoperative methadone included hydromorphone, ketamine, and sufentanil. Considering patient outcomes, included studies observed that patients treated with intraoperative methadone had statistically similar or significantly reduced pain scores, opioid usage, and LOS compared with comparator analgesics. However, one study observed that intraoperative methadone used in a multimodal analgesia regimen strategy with ketamine resulted in a shortened LOS compared with the use of intraoperative methadone alone. Differences in operating time between cases that used intraoperative methadone and cases that used comparator analgesics were not statistically significant among included studies.

CONCLUSION

Methadone may present an alternative option for both intraoperative and postoperative analgesia in spine surgery recovery protocols and may reduce postoperative pain, opioid use, and LOS while maintaining consistent operating time and reduced side effects of pure mu opioids.

LEVEL OF EVIDENCE

Level II.

Opioid Use Prior to Adult Spine Deformity Correction Surgery is Associated With Worse Pre- and Postoperative Back Pain and Prolonged Opioid Demands

STUDY DESIGN

Prospective multicenter database post-hoc analysis.

OBJECTIVES

Opioids are frequently prescribed for painful spinal conditions to provide pain relief and to allow for functional improvement, both before and after spine surgery. Amidst a current opioid epidemic, it is important for providers to understand the impact of opioid use and its relationship with patient-reported outcomes. The purpose of this study was to evaluate pre-/postoperative opioid consumption surrounding ASD and assess patient-reported pain outcomes in older patients undergoing surgery for spinal deformity.

METHODS

Patients ≥60 years of age from 12 international centers undergoing spinal fusion of at least 5 levels and a minimum 2-year follow-up were included. Patient-reported outcome scores were collected using the Numeric Rating Scale for back and leg pain (NRS-B; NRS-L) at baseline and at 2 years following surgery. Opioid use, defined based on a specific question on case report forms and question 11 from the SRS-22r questionnaire, was assessed at baseline and at 2-year follow-up.

RESULT

Of the 219 patients who met inclusion criteria, 179 (81.7%) had 2-year data on opioid use. The percentages of patients reporting opioid use at baseline (n = 75, 34.2%) and 2 years after surgery (n = 55, 30.7%) were similar (P = .23). However, at last follow-up 39% of baseline opioid users (Opi) were no longer taking opioids, while 14% of initial non-users (No-Opi) reported opioid use. Regional pre- and postoperative opioid use was 5.8% and 7.7% in the Asian population, 58.3% and 53.1% in the European, and 50.5% and 40.2% in North American patients, respectively. Baseline opioid users reported more preoperative back pain than the No-Opi group (7.0 vs 5.7, P = .001), while NRS-Leg pain scores were comparable (4.8 vs 4, P = .159). Similarly, at last follow-up, patients in the Opi group had greater NRS-B scores than Non-Opi patients (3.2 vs 2.3, P = .012), but no differences in NRS-Leg pain scores (2.2 vs 2.4, P = .632) were observed.

CONCLUSIONS

In this study, almost one-third of surgical ASD patients were consuming opioids both pre- and postoperatively world-wide. There were marked international variations, with patients from Asia having a much lower usage rate, suggesting a cultural influence. Despite both opioid users and nonusers benefitting from surgery, preoperative opioid use was strongly associated with significantly more back pain at baseline that persisted at 2-year follow up, as well as persistent postoperative opioid needs.

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.

Association of inpatient opioid consumption on postoperative outcomes after open posterior spinal fusion for adult spine deformity

INTRODUCTION

Opioids are the most commonly used analgesic in the postoperative setting. However, few studies have analyzed the impact of high inpatient opioid use on outcomes following surgery, with no current studies assessing its effect on patients undergoing spinal fusion for an adult spinal deformity (ASD). Thus, the aim of this study was to investigate risk factors for high inpatient opioid use, as well as to determine the impact of high opioid use on outcomes such as adverse events (AEs), hospital length of stay (LOS), cost of hospital admission, discharge disposition, and readmission rates in patients undergoing spinal fusion for ASD.

METHODS

A retrospective cohort study was performed using the Premier healthcare database from the years 2016 and 2017. All adult patients > 40 years old who underwent thoracic or thoracolumbar fusion for ASD were identified using the ICD-10-CM diagnostic and procedural coding system. Patients were then categorized into three cohorts based on inpatient opioid use: Low MME (morphine milligram equivalents), Medium MME, and High MME. Patient demographics, comorbidities, treating hospital characteristics, intraoperative variables, postoperative AEs, LOS, discharge disposition, and total cost of hospital admission were assessed in the analysis. Multivariate regression analysis was done to determine independent predictors of high inpatient MME, prolonged LOS, and increased hospital cost.

RESULTS

Of 1673 patients included, 417 (24.9%) were classified as Low MME, 840 (50.2%) as Medium MME, and 416 (24.9%) as High MME. Age significantly decreased with increasing MME (Low: 71.0% 65 + years vs Medium: 62.0% 65 + years vs High: 47.4% 65 + years, p < 0.001), while the proportions of patients presenting with three or more comorbidities were similar across the cohorts (Low: 20.1% with 3 + comorbidities vs Medium: 18.0% with 3 + comorbidities vs High: 24.3% with 3 + comorbidities, p = 0.070). With respect to postoperative outcomes, the proportion of patients who experienced any AE (Low: 60.2% vs Medium: 68.8% vs High: 70.9%, p = 0.002), extended LOS (Low: 6.7% vs Medium: 20.7% vs High: 45.4%, p < 0.001), or non-routine discharge (Low: 66.6% vs Medium: 73.5% vs High: 80.1%, p = 0.003) each increased along with total MME. In addition, rates of 30-day readmission were greatest among the High MME cohort (Low: 8.4% vs Medium: 7.9% vs High: 12.5%, p = 0.022). On multivariate analysis, medium and high MME were associated with prolonged LOS [Medium: OR 4.41, CI (2.90, 6.97); High: OR 13.99, CI (8.99, 22.51), p < 0.001] and increased hospital cost [Medium: OR 1.69, CI (1.21, 2.39), p = 0.002; High: OR 1.66, CI (1.12, 2.46), p = 0.011]. Preadmission long-term opioid use [OR 1.71, CI (1.07, 2.7), p = 0.022], a prior opioid-related disorder [OR 11.32, CI (5.92, 23.49), p < 0.001], and chronic pulmonary disease [OR 1.39, CI (1.06, 1.82), p = 0.018] were each associated with a high inpatient MME on multivariate analysis.

CONCLUSION

Our study demonstrated that increasing inpatient MME consumption was associated with extended LOS and increased hospital cost in patients undergoing spinal fusion for ASD. Further studies identifying risk factors for increased MME consumption may provide better risk stratification for postoperative opioid use and healthcare resource utilization.

Perioperative Low-Dose Ketamine for Postoperative Pain Management in Spine Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

Although low-dose ketamine has been shown to be generally beneficial in terms of pain control in a variety of major surgery, there is no consensus regarding the effectiveness of supplemental ketamine analgesic use exclusively in spine surgery. The objective of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to assess the efficacy and safety of perioperative low-dose ketamine for pain management and analgesic consumption in patients undergoing spine surgery.

Methods

A comprehensive literature search was performed for relevant studies using PubMed, EMBASE, Web of Science, and Cochrane Library. Patients who received perioperative low-dose ketamine were compared to the control group in terms of postoperative pain intensity, opioid consumption, and adverse events. Patients were further categorized by ages and administration times for subgroup analysis.

Results

A total of 30 RCTs comprising 1,865 patients undergoing elective spine surgery were included. Significantly lower pain intensity and less opioid consumption at 12 h, 24 h, and 48 h postoperatively and lower incidence of postoperative nausea and vomiting (PONV) were observed in the ketamine group (all P < 0.05). There was no significant difference of central nervous system (CNS) adverse events between groups. However, different efficacy of low-dose ketamine was detected when patients were categorized by ages and administration times.

Conclusion

Perioperative low-dose ketamine demonstrated analgesic and morphine-sparing effect with no increased adverse events after spine surgery. However, this effect was not significant in pediatric patients. Only postoperative or intraoperative and postoperative administration could prolong the analgesic time up to 48 h postoperatively. Further studies should focus on the optimal protocol of ketamine administration and its effect on old age participants.

Perioperative Multimodal Analgesia for Adults undergoing surgery of the Spine- Systematic Review and Meta-analysis of Three or More Modalities

BACKGROUND

Multimodal analgesia is a strategy which may be employed to improve pain management in the perioperative period in patients undergoing surgery of the spine. However, there is no review evidence available on quantitative models of multimodal analgesia within this clinical setting. We conducted a systematic review and meta-analysis to examine the impact of maximal (three or more analgesic agents) multimodal analgesic medication in patients undergoing surgery of the spine.

METHODS

We included randomized controlled trials (RCT's) evaluating the use of three or more multimodal analgesia components (maximal multi modal analgesia) in patients undergoing spinal surgery. We excluded patients receiving neuraxial or regional analgesia. The control group consisted of placebo, standard care (any therapeutic modality including two or less analgesic components). Primary outcomes were post-operative pain scores at rest, at twenty-four, and forty eight hours. We searched the MEDLINE via Ovid SP; EMBASE via Ovid SP; and Cochrane Library (Cochrane Database of Systematic Reviews and CENTRAL). We used Cochrane's standard methods.

RESULTS

We identified consistently improved analgesic endpoints across all pre-determined primary and secondary outcomes. A total of eleven eligible studies evaluated the primary outcome of pain at rest at twenty four hours. Patients receiving maximal multimodal analgesia were identified to have lower pain scores with an average of MD [-1.03], p<0.00001. Length of hospital stay was decreased in patients receiving multimodal analgesia MD [-0.55], p<0.00001.

CONCLUSION

Perioperative maximal multimodal analgesia consistently improves visual analogue scale outcomes in adult population in the immediate post-operative period, with a moderate quality of evidence. There is significant decrease in hospital length of stay in patients receiving maximal multimodal analgesia with a high level of evidence and no statistical heterogeneity.

Effects of Esketamine on Acute and Chronic Pain After Thoracoscopy Pulmonary Surgery Under General Anesthesia: A Multicenter-Prospective, Randomized, Double-Blind, and Controlled Trial

Background: Post-operative pain management for patients undergoing thoracoscopy surgery is challenging for clinicians which increase both health and economic burden. The non-selective NMDA receptor antagonist esketamine possesses an analgesic effect twice that of ketamine. The application of esketamine might be beneficial in alleviating acute and chronic pain after thoracic surgery. The current study describes the protocol aiming to evaluate the analgesic effect of esketamine after pulmonary surgery via visual analog scale (VAS) score for acute and chronic pain.

Methods: A multi-center, prospective, randomized, controlled, double-blind study is designed to explore the analgesic effect of esketamine in randomized patients undergoing video-assisted thoracoscopic surgery (VATS) with general anesthesia. Patients will be randomly assigned to Esketamine Group (Group K) and Control Group (Group C) in a ratio of 1:1. Group K patients will receive esketamine with a bolus of 0.1 mg/kg after anesthesia induction, 0.1 mg/kg/h throughout the operation and 0.015 mg/kg/h in PCIA after surgery while Group C patients will receive the same volume of normal saline. The primary outcome is to measure the pain intensity through the VAS score at 3 months after the operation. The secondary outcome includes VAS score at 1, 4, 8, 24, and 48 h and on the 7th day and 1 month after the operation, complications, ketamine-related neurological side effects, recovery time of bowel function, and total amount of supplemental analgesics.

Discussion: The results of the current study might illustrate the analgesic effect of esketamine for patients undergoing thoracoscopy pulmonary surgery and provide evidence and insight for perioperative pain management.

Study Registration: The trial was registered with Chinese Clinical Trial Registry (CHICTR) on Nov 18th, 2020 (ChiCTR2000040012).

Perioperative Care of Patients Undergoing Major Complex Spinal Instrumentation Surgery: Clinical Practice Guidelines From the Society for Neuroscience in Anesthesiology and Critical Care

Evidence-based standardization of the perioperative management of patients undergoing complex spine surgery can improve outcomes such as enhanced patient satisfaction, reduced intensive care and hospital length of stay, and reduced costs. The Society for Neuroscience in Anesthesiology and Critical Care (SNACC) tasked an expert group to review existing evidence and generate recommendations for the perioperative management of patients undergoing complex spine surgery, defined as surgery on 2 or more thoracic and/or lumbar spine levels. Institutional clinical management protocols can be constructed based on the elements included in these clinical practice guidelines, and the evidence presented.

Pain management after complex spine surgery: A systematic review and procedure-specific postoperative pain management recommendations

BACKGROUND

Complex spinal procedures are associated with intense pain in the postoperative period. Adequate peri-operative pain management has been shown to correlate with improved outcomes including early ambulation and early discharge.

OBJECTIVES

We aimed to evaluate the available literature and develop recommendations for optimal pain management after complex spine surgery.

DESIGN AND DATA SOURCES

A systematic review using the PROcedure SPECific postoperative pain managemenT methodology was undertaken. Randomised controlled trials and systematic reviews published in the English language from January 2008 to April 2020 assessing postoperative pain after complex spine surgery using analgesic, anaesthetic or surgical interventions were identified from MEDLINE, EMBASE and Cochrane Databases.

RESULTS

Out of 111 eligible studies identified, 31 randomised controlled trials and four systematic reviews met the inclusion criteria. Pre-operative and intra-operative interventions that improved postoperative pain were paracetamol, cyclo-oxygenase (COX)-2 specific-inhibitors or non-steroidal anti-inflammatory drugs (NSAIDs), intravenous ketamine infusion and regional analgesia techniques including epidural analgesia using local anaesthetics with or without opioids. Limited evidence was found for local wound infiltration, intrathecal and epidural opioids, erector spinae plane block, thoracolumbar interfascial plane block, intravenous lidocaine, dexmedetomidine and gabapentin.

CONCLUSIONS

The analgesic regimen for complex spine surgery should include pre-operative or intra-operative paracetamol and COX-2 specific inhibitors or NSAIDs, continued postoperatively with opioids used as rescue analgesics. Other recommendations are intra-operative ketamine and epidural analgesia using local anaesthetics with or without opioids. Although there is procedure-specific evidence in favour of intra-operative methadone, it is not recommended as it was compared with shorter-acting opioids and due to its limited safety profile. Furthermore, the methadone studies did not use non-opioid analgesics, which should be the primary analgesics to ultimately reduce overall opioid requirements, including methadone. Further qualitative randomised controlled trials are required to confirm the efficacy and safety of these recommended analgesics on postoperative pain relief.

S-ketamine in patient-controlled analgesia reduces opioid consumption in a dose-dependent manner after major lumbar fusion surgery: A randomized, double-blind, placebo-controlled clinical trial

Background

Spinal fusion surgery causes severe pain. Strong opioids, commonly used as postoperative analgesics, may have unwanted side effects. S-ketamine may be an effective analgesic adjuvant in opioid patient-controlled analgesia (PCA). However, the optimal adjunct S-ketamine dose to reduce postoperative opioid consumption is still unknown.

Methods

We randomized 107 patients at two tertiary hospitals in a double-blinded, placebo-controlled clinical trial of adults undergoing major lumbar spinal fusion surgery. Patients were randomly allocated to four groups in order to compare the effects of three different doses of adjunct S-ketamine (0.25, 0.5, and 0.75 mg ml-1) or placebo on postoperative analgesia in oxycodone PCA. Study drugs were administered for 24 hours postoperative after which oxycodone-PCA was continued for further 48 hours. Our primary outcome was cumulative oxycodone consumption at 24 hours after surgery.

Results

Of the 100 patients analyzed, patients receiving 0.75 mg ml^-1 S-ketamine in oxycodone PCA needed 25% less oxycodone at 24 h postoperatively (61.2 mg) compared with patients receiving 0.5 mg ml^-1 (74.7 mg) or 0.25 mg ml^-1 (74.1 mg) S-ketamine in oxycodone or oxycodone alone (81.9 mg) (mean difference: -20.6 mg; 95% confidence interval [CI]: -41 to -0.20; P = 0.048). A beneficial effect in mean change of pain intensity at rest was seen in the group receiving 0.75 mg ml^-1 S-ketamine in oxycodone PCA compared with patients receiving lower ketamine doses or oxycodone alone (standardized effect size: 0.17, 95% CI: 0.013–0.32, P = 0.033). The occurrence of adverse events was similar among the groups.

Conclusions

Oxycodone PCA containing S-ketamine as an adjunct at a ratio of 1: 0.75 decreased cumulative oxycodone consumption at 24 h after major lumbar spinal fusion surgery without additional adverse effects.

Perioperative Methadone and Ketamine for Postoperative Pain Control in Spinal Surgical Patients: A Randomized, Double-blind, Placebo-controlled Trial

BACKGROUND

Despite application of multimodal pain management strategies, patients undergoing spinal fusion surgery frequently report severe postoperative pain. Methadone and ketamine, which are N-methyl-d-aspartate receptor antagonists, have been documented to facilitate postoperative pain control. This study therefore tested the primary hypothesis that patients recovering from spinal fusion surgery who are given ketamine and methadone use less hydromorphone on the first postoperative day than those give methadone alone.

METHODS

In this randomized, double-blind, placebo-controlled trial, 130 spinal surgery patients were randomized to receive either methadone at 0.2 mg/kg (ideal body weight) intraoperatively and a 5% dextrose in water infusion for 48 h postoperatively (methadone group) or 0.2 mg/kg methadone intraoperatively and a ketamine infusion (0.3 mg · kg-1 · h-1 infusion [no bolus] intraoperatively and then 0.1 mg · kg-1 · h-1 for next 48 h [both medications dosed at ideal body weight]; methadone/ketamine group). Anesthetic care was standardized in all patients. Intravenous hydromorphone use on postoperative day 1 was the primary outcome. Pain scores, intravenous and oral opioid requirements, and patient satisfaction with pain management were assessed for the first 3 postoperative days.

RESULTS

Median (interquartile range) intravenous hydromorphone requirements were lower in the methadone/ketamine group on postoperative day 1 (2.0 [1.0 to 3.0] vs. 4.6 [3.2 to 6.6] mg in the methadone group, median difference [95% CI] 2.5 [1.8 to 3.3] mg; P < 0.0001) and postoperative day 2. In addition, fewer oral opioid tablets were needed in the methadone/ketamine group on postoperative day 1 (2 [0 to 3] vs. 4 [0 to 8] in the methadone group; P = 0.001) and postoperative day 3. Pain scores at rest, with coughing, and with movement were lower in the methadone/ketamine group at 23 of the 24 assessment times. Patient-reported satisfaction scores were high in both study groups.

CONCLUSIONS

Postoperative analgesia was enhanced by the combination of methadone and ketamine, which act on both N-methyl-d-aspartate and μ-opioid receptors. The combination could be considered in patients having spine surgery.

EDITOR’S PERSPECTIVE

Consensus statement for perioperative care in lumbar spinal fusion: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Enhanced Recovery After Surgery (ERAS) evidence-based protocols for perioperative care have led to improvements in outcomes in numerous surgical areas, through multimodal optimization of patient pathway, reduction of complications, improved patient experience and reduction in the length of stay. ERAS represent a relatively new paradigm in spine surgery.

PURPOSE

This multidisciplinary consensus review summarizes the literature and proposes recommendations for the perioperative care of patients undergoing lumbar fusion surgery with an ERAS program.

STUDY DESIGN

This is a review article.

METHODS

Under the impetus of the ERAS® society, a multidisciplinary guideline development group was constituted by bringing together international experts involved in the practice of ERAS and spine surgery. This group identified 22 ERAS items for lumbar fusion. A systematic search in the English language was performed in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Systematic reviews, randomized controlled trials, and cohort studies were included, and the evidence was graded according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Consensus recommendation was reached by the group after a critical appraisal of the literature.

RESULTS

Two hundred fifty-six articles were included to develop the consensus statements for 22 ERAS items; one ERAS item (prehabilitation) was excluded from the final summary due to very poor quality and conflicting evidence in lumbar spinal fusion. From these remaining 21 ERAS items, 28 recommendations were included. All recommendations on ERAS protocol items are based on the best available evidence. These included nine preoperative, eleven intraoperative, and six postoperative recommendations. They span topics from preoperative patient education and nutritional evaluation, intraoperative anesthetic and surgical techniques, and postoperative multimodal analgesic strategies. The level of evidence for the use of each recommendation is presented.

CONCLUSION

Based on the best evidence available for each ERAS item within the multidisciplinary perioperative care pathways, the ERAS® Society presents this comprehensive consensus review for perioperative care in lumbar fusion.

The role of perioperative ketamine in postoperative pain control following spinal surgery

Opioid abuse has rapidly developed into an epidemic across the United States. Patients are often introduced to opioids following surgical procedures-this is particularly relevant following spinal surgery. Surgeons can help reduce this opioid burden by finding alternatives to narcotic analgesia in the postoperative period. One such medication that has shown potential in this role is ketamine, which has been studied in various surgical specialties. A review was performed of current literature regarding ketamine use in the perioperative period specific to spinal surgery. This review focused on prospective randomized control trials; the primary endpoint was opioid consumption in the postoperative period, monitored through patient-controlled analgesia (PCA) use. Both pediatric and adult spinal surgery patients were included; cervical, thoracic, and lumbar procedures were also all included. 10 studies were selected for this reviewed based on inclusion criteria, published between 2004 and 2017. 7 of these studies demonstrated a significant decrease in postoperative opioid use with the integration of ketamine in the perioperative period, while 3 trials showed no significant difference in opioid consumption. There is inherent difficulty in standardizing studies of this nature-dosing protocols, medication timing, and supplemental analgesia were variable throughout the included studies. However, this review of the most up-to-date prospective studies indicate ketamine has potential to play a significant role in reducing opioid requirements following spinal surgery, and further study is warranted in this field.

Opioid Alternatives in Spine Surgery: A Narrative Review

Adequate analgesia is known to improve outcomes after spine surgery. Despite recent attention highlighting the negative effects of narcotics and their addiction potential, opioids have been the mainstay of management for providing analgesia following spine surgeries. However, side effects including hyperalgesia, tolerance, and subsequent dependence restrict the generous usage of opioids. Multimodal analgesia regimens acting through different mechanisms offer significant opioid sparing and minimize the side effects of individual drugs. Hence, they are being increasingly incorporated into enhanced recovery protocols. Multimodal analgesia includes drugs such as N-methyl-D-aspartate antagonists, nonsteroidal anti-inflammatory drugs and membrane-stabilizing agents, neuraxial opioids, local anesthetic infiltration, and fascial compartment blocks. Analgesia started before the painful stimulus, termed preemptive analgesia, facilitates subsequent pain management. Both nonsteroidal anti-inflammatory drugs and neuraxial analgesia have been conclusively shown to reduce opioid requirements after spine surgery, and there is a resurgence of interest in the use of low-dose ketamine or methadone. Neuraxial narcotics offer enhanced analgesia for a longer duration with lower dosage and side effect profiles compared with systemic opioid administration. Fascial compartment blocks are increasingly used as they provide effective analgesia with fewer adverse effects. In this narrative review, we will discuss multimodality analgesic regimens incorporating opioid-sparing adjuvants to manage pain after spine surgery.

Methadone for postoperative analgesia: contribution of N-methyl-D-aspartate receptor antagonism: A randomised controlled trial

BACKGROUND

Over the past number of years, N-methyl-D-aspartate (NMDA) inhibitory drugs, like ketamine, have been introduced as adjuvant treatments for postoperative acute pain, within a multimodal approach. A further extension of this strategy could be the use of opioids with NMDA receptor (NMDAr) antagonism activity for control of postoperative pain. Methadone has a unique pharmacodynamic profile: it is both a μ-agonist and an NMDAr-blocker.

OBJECTIVE

We designed this study to investigate the precise contribution of NMDAr antagonism in methadone-induced analgesia.

DESIGN

Single-centre, prospective, randomised, double-blind study.

SETTING

National Cancer Center - Fondazione IRCCS Istituto Nazionale Tumori Milano; patients were recruited between March 2010 and June 2012.

PATIENTS

Ninety-six patients scheduled for an open laparotomy for anterior resection of the rectum.

INTERVENTIONS

We randomly assigned patients to four groups: 0-Mo (placebo and morphine), K-Mo [S(+)-ketamine and morphine], 0-Me (placebo and methadone), K-Me [S(+)-ketamine and methadone].

MAIN OUTCOME MEASURES

The primary end-point was the extent of mechanical static (punctuate) hyperalgesia to von Frey hair stimulation lateral to the surgical incision.

RESULTS

Peri-incisional hyperalgesia was 8.4 cm (95% confidence interval, 1.5 to 15.41) lower in the treatment group (K-Me) compared with the control group (0-Mo) at 24 h after surgery (P = 0.02). No significant differences were observed between the groups at 48 h after surgery (P = 0.88). Both groups treated with methadone had significantly lower pain during rest and movement, as measured with a Numerical Rating Scale at 24 h. At 48 h, only the movement Numerical Rating Scale was significantly lower. No difference occurred in opioid consumption.

CONCLUSION

Methadone provides effective control of acute postoperative pain, independently, by modulation of the hyperalgesia mechanism.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, no.: NCT01594047.

An Update on the Basic and Clinical Science of Ketamine Analgesia

OBJECTIVE

In the context of the current opioid epidemic, there has been a renewed interest in the use of ketamine as an analgesic agent.

METHODS

We reviewed ketamine analgesia.

RESULTS

Ketamine is well-known as an antagonist for N-methyl-D-aspartate receptors. In addition, it can regulate the function of opioid receptors and sodium channels. Ketamine also increases signaling through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. These myriad of molecular and cellular mechanisms are responsible for a number of pharmacological functions including pain relief and mood regulation. Clinically, a number of studies have investigated the role of ketamine in the setting of acute and chronic pain, and there is evidence that ketamine can provide analgesia in a variety of pain syndromes.

DISCUSSION

In this review, we examined basic mechanisms of ketamine and its current clinical use and potential novel use in pain management.

The effect of induction with propofol or ketamine and diazepam on quality of anaesthetic recovery in dogs

OBJECTIVE

To evaluate the quality of recovery in dogs undergoing elective orthopaedic surgery induced with either propofol or a combination of ketamine and diazepam.

MATERIALS AND METHODS

Sixty client-owned dogs undergoing single-limb elective orthopaedic procedures were enrolled. Dogs were randomly assigned to receive induction with propofol (4 mg/kg) (group P) or ketamine (5 mg/kg) with diazepam (0.25 mg/kg) (group KD) to which all scorers were blinded. The recovery monitoring period lasted for 1 hour following extubation. The recovery period was video-recorded for blinded scoring at a later time. Scoring for quality of recovery was carried out using three different systems (lower numbers=better quality): a simple descriptive scale (1 to 5), a visual analogue scale (0 to 10 cm) and a numeric rating scale (0 to 10). Videos were reviewed by three ACVAA board-certified anaesthesiologist raters.

RESULTS

Five dogs were deemed to be ineligible. The mean (±SD) duration of anaesthesia was 260.4 ±57.84 minutes in group KD and 261.1 ±51.83 minutes in group P. There was no difference between groups for time to extubation, head lift or sternal recumbency. The number of dogs having a recovery that was scored overall as bad (mean simple descriptive scale > 4, mean visual analogue scale or numeric rating scale > 5) was not different between groups. Dogs in group KD had significantly lower scores than group P dogs (simple descriptive scale P=0.01, numeric rating scale P=0.03, visual analogue scale P=0.03).

CLINICAL SIGNIFICANCE

Induction with ketamine and diazepam resulted in a smoother recovery from anaesthesia than induction with propofol.

Intraoperative Ketamine in Total Knee Arthroplasty Does Not Decrease Pain and Narcotic Consumption: A Prospective Randomized Controlled Trial

BACKGROUND

Multiple studies have demonstrated that ketamine, a glutamate receptor blocker, may decrease postoperative pain in abdominal and orthopedic surgeries. However, its role with spinal anesthesia and total knee arthroplasty (TKA) remains unknown. The purpose of this study is to determine the efficacy of subanesthetic dosing of ketamine during TKA on postoperative pain and narcotic consumption.

METHODS

In this prospective, randomized, double-blinded clinical trial, we enrolled 91 patients undergoing primary TKA with spinal anesthesia in a single institution from 2017 to 2018. Patients were randomized to receive intraoperative ketamine infusion at a rate of 6 mcg/kg/min for 75 minutes or a saline placebo. All patients received spinal anesthesia and otherwise identical surgical approaches, pain management, and rehabilitation protocols. Patient-reported visual analog pain scores were calculated preoperatively, postoperative days (POD) 0-7, and 2 weeks. Narcotic consumption was evaluated on POD 0 and 1.

RESULTS

There was no difference in average pain between ketamine and placebo at all time points except for at PODs 1 (45 vs 56, P = .041) and 4 (39 vs 49, P = .040). For least pain experienced, patients administered with ketamine experienced a reduction in pain only at POD 4 (22 vs 35, P = .011). There was no difference in maximum pain cohorts at all time points of the study or in-hospital morphine equivalents between the 2 cohorts.

CONCLUSION

As part of multimodal pain management protocol, intraoperative ketamine does not result in a clinically significant improvement in pain and narcotic consumption following TKA.

Perioperative ketamine for acute analgesia and beyond

There has been substantial interest in the use of ketamine for perioperative analgesia. Recently published articles on 'low dose' ketamine mark the resurgence in interest in the use of the drug for acute pain. Continued interest in ketamine as an anti-depressant also has opened the door to applications beyond the operating room. In this article, we will review: the history of ketamine's clinical use; basic ketamine pharmacology; evidence for the use of perioperative ketamine for analgesia; comments on patient selection for ketamine research; a discussion of the safety and side effect profile of ketamine infusions beyond the operating room; and, lastly, ketamine as a treatment option for psychiatric diseases.

Perioperative intravenous ketamine for acute postoperative pain in adults

BACKGROUND

Inadequate pain management after surgery increases the risk of postoperative complications and may predispose for chronic postsurgical pain. Perioperative ketamine may enhance conventional analgesics in the acute postoperative setting.

OBJECTIVES

To evaluate the efficacy and safety of perioperative intravenous ketamine in adult patients when used for the treatment or prevention of acute pain following general anaesthesia.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to July 2018 and three trials registers (metaRegister of controlled trials, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP)) together with reference checking, citation searching and contact with study authors to identify additional studies.

SELECTION CRITERIA

We sought randomised, double-blind, controlled trials of adults undergoing surgery under general anaesthesia and being treated with perioperative intravenous ketamine. Studies compared ketamine with placebo, or compared ketamine plus a basic analgesic, such as morphine or non-steroidal anti-inflammatory drug (NSAID), with a basic analgesic alone.

DATA COLLECTION AND ANALYSIS

Two review authors searched for studies, extracted efficacy and adverse event data, examined issues of study quality and potential bias, and performed analyses. Primary outcomes were opioid consumption and pain intensity at rest and during movement at 24 and 48 hours postoperatively. Secondary outcomes were time to first analgesic request, assessment of postoperative hyperalgesia, central nervous system (CNS) adverse effects, and postoperative nausea and vomiting. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

We included 130 studies with 8341 participants. Ketamine was given to 4588 participants and 3753 participants served as controls. Types of surgery included ear, nose or throat surgery, wisdom tooth extraction, thoracotomy, lumbar fusion surgery, microdiscectomy, hip joint replacement surgery, knee joint replacement surgery, anterior cruciate ligament repair, knee arthroscopy, mastectomy, haemorrhoidectomy, abdominal surgery, radical prostatectomy, thyroid surgery, elective caesarean section, and laparoscopic surgery. Racemic ketamine bolus doses were predominantly 0.25 mg to 1 mg, and infusions 2 to 5 µg/kg/minute; 10 studies used only S-ketamine and one only R-ketamine. Risk of bias was generally low or uncertain, except for study size; most had fewer than 50 participants per treatment arm, resulting in high heterogeneity, as expected, for most analyses. We did not stratify the main analysis by type of surgery or any other factor, such as dose or timing of ketamine administration, and used a non-stratified analysis.Perioperative intravenous ketamine reduced postoperative opioid consumption over 24 hours by 8 mg morphine equivalents (95% CI 6 to 9; 19% from 42 mg consumed by participants given placebo, moderate-quality evidence; 65 studies, 4004 participants). Over 48 hours, opioid consumption was 13 mg lower (95% CI 10 to 15; 19% from 67 mg with placebo, moderate-quality evidence; 37 studies, 2449 participants).Perioperative intravenous ketamine reduced pain at rest at 24 hours by 5/100 mm on a visual analogue scale (95% CI 4 to 7; 19% lower from 26/100 mm with placebo, high-quality evidence; 82 studies, 5004 participants), and at 48 hours by 5/100 mm (95% CI 3 to 7; 22% lower from 23/100 mm, high-quality evidence; 49 studies, 2962 participants). Pain during movement was reduced at 24 hours (6/100 mm, 14% lower from 42/100 mm, moderate-quality evidence; 29 studies, 1806 participants), and 48 hours (6/100 mm, 16% lower from 37 mm, low-quality evidence; 23 studies, 1353 participants).Results for primary outcomes were consistent when analysed by pain at rest or on movement, operation type, and timing of administration, or sensitivity to study size and pain intensity. No analysis by dose was possible. There was no difference when nitrous oxide was used. We downgraded the quality of the evidence once if numbers of participants were large but small-study effects were present, or twice if numbers were small and small-study effects likely but testing not possible.Ketamine increased the time for the first postoperative analgesic request by 54 minutes (95% CI 37 to 71 minutes), from a mean of 39 minutes with placebo (moderate-quality evidence; 31 studies, 1678 participants). Ketamine reduced the area of postoperative hyperalgesia by 7 cm² (95% CI -11.9 to -2.2), compared with placebo (very low-quality evidence; 7 studies 333 participants). We downgraded the quality of evidence because of small-study effects or because the number of participants was below 400.CNS adverse events occurred in 52 studies, while 53 studies reported of absence of CNS adverse events. Overall, 187/3614 (5%) participants receiving ketamine and 122/2924 (4%) receiving control treatment experienced an adverse event (RR 1.2, 95% CI 0.95 to 1.4; high-quality evidence; 105 studies, 6538 participants). Ketamine reduced postoperative nausea and vomiting from 27% with placebo to 23% with ketamine (RR 0.88, 95% CI 0.81 to 0.96; the number needed to treat to prevent one episode of postoperative nausea and vomiting with perioperative intravenous ketamine administration was 24 (95% CI 16 to 54; high-quality evidence; 95 studies, 5965 participants).

AUTHORS' CONCLUSIONS

Perioperative intravenous ketamine probably reduces postoperative analgesic consumption and pain intensity. Results were consistent in different operation types or timing of ketamine administration, with larger and smaller studies, and by higher and lower pain intensity. CNS adverse events were little different with ketamine or control. Perioperative intravenous ketamine probably reduces postoperative nausea and vomiting by a small extent, of arguable clinical relevance.

Perioperative Ketamine for Analgesia in Spine Surgery: A Meta-analysis of Randomized Controlled Trials

STUDY DESIGN

A meta-analysis of randomized controlled trials (RCTs).

OBJECTIVE

The aim of this study was to evaluate the effectiveness of perioperative supplemental ketamine to reduce postoperative opioid analgesic consumption following spine surgery.

SUMMARY OF BACKGROUND DATA

Although low-dose supplemental ketamine has been known to reduce pain after surgery, there is conflicting evidence regarding whether ketamine can be effective to reduce opioid consumption following spine surgery.

METHODS

Comprehensive search of PubMed, the Cochrane Central Register of Controlled Trials for prospective RCTs, Web of Science, and Scopus. Patients who received supplemental ketamine were compared with the control group in terms of postoperative morphine equivalent consumption, pain scores, and adverse events. Mean differences (MDs) and 95% confidence intervals (CIs) were used to describe continuous outcomes. Odds ratios (ORs) and 95% CIs were applied to dichotomous outcomes.

RESULTS

A total of 14 RCTs comprising 649 patients were selected for inclusion into the meta-analysis. Patients who were administered adjunctive ketamine exhibited less cumulative morphine equivalent consumption at 4, 8, 12, and 24 hours following spine surgery (all Ps < 0.05). The ketamine group also reported lower postoperative pain scores at 6, 12, and 24 hours (all Ps < 0.05). None of the adverse events studied attained statistical significance (all Ps > 0.05).

CONCLUSION

Supplemental perioperative ketamine reduces postoperative opioid consumption up to 24 hours following spine surgery.

LEVEL OF EVIDENCE

1.

Benefit and harm of adding ketamine to an opioid in a patient-controlled analgesia device for the control of postoperative pain: systematic review and meta-analyses of randomized controlled trials with trial sequential analyses

Ketamine is often added to opioids in patient-controlled analgesia devices. We tested whether in surgical patients, ketamine added to an opioid patient-controlled analgesia decreased pain intensity by ≥25%, cumulative opioid consumption by ≥30%, the risk of postoperative nausea and vomiting by ≥30%, the risk of respiratory adverse effects by ≥50%, and increased the risk of hallucination not more than 2-fold. In addition, we searched for evidence of dose-responsiveness. Nineteen randomized trials (1349 adults, 104 children) testing different ketamine regimens added to various opioids were identified through searches in databases and bibliographies (to 04.2016). In 9 trials (595 patients), pain intensity at rest at 24 hours was decreased by 32% with ketamine (weighted mean difference -1.1 cm on the 0-10 cm visual analog scale [98% CI, -1.8 to -0.39], P < 0.001). In 7 trials (495 patients), cumulative 24 hours morphine consumption was decreased by 28% with ketamine (weighted mean difference -12.9 mg [-22.4 to -3.35], P = 0.002). In 7 trials (435 patients), the incidence of postoperative nausea and vomiting was decreased by 44% with ketamine (risk ratio 0.56 [0.40 to 0.78], P < 0.001). There was no evidence of a difference in the incidence of respiratory adverse events (9 trials, 871 patients; risk ratio 0.31 [0.06 to 1.51], P = 0.08) or hallucination (7 trials, 690 patients; odds ratio 1.16 [0.47 to 2.79], P = 0.70). Trial sequential analyses confirmed the significant benefit of ketamine on pain intensity, cumulative morphine consumption, and postoperative nausea and vomiting and its inability to double the risk of hallucination. The available data did not allow us to make a conclusion on respiratory adverse events or to establish dose-responsiveness.

Chronic Pain in Neurosurgery

This review includes a summary of contemporary theories of pain processing and advocates a multimodal analgesia approach for providing perioperative care. A summary of various medication classes and anesthetic techniques is provided that highlights evidence emerging from neurosurgical literature. This summary covers opioid management, acetaminophen, nonsteroidal antiinflammatories, ketamine, lidocaine, dexmedetomidine, corticosteroids, gabapentin, and regional anesthesia for neurosurgery. At present, there is not enough investigation into these areas to describe best practices for treating or preventing chronic pain in neurosurgery; but providers can identify a wider range of options available to personalize perioperative care strategies.

Novel polymeric bioerodable microparticles for prolonged-release intrathecal delivery of analgesic agents for relief of intractable cancer-related pain

Intractable cancer-related pain complicated by a neuropathic component due to nerve impingement is poorly alleviated even by escalating doses of a strong opioid analgesic. To address this unmet medical need, we developed sustained-release, bioerodable, hydromorphone (potent strong opioid)- and ketamine (analgesic adjuvant)-loaded microparticles for intrathecal (i.t.) coadministration. Drug-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were prepared using a water-in-oil-in-water method with evaporation. Encapsulation efficiency of hydromorphone and ketamine in PLGA (50:50) microparticles was 26% and 56%, respectively. Microparticles had the desired size range (20-60 μm) and in vitro release was prolonged at ≥28 days. Microparticles were stable for ≥6 months when stored refrigerated protected from light in a desiccator. Desirably, i.t. injected fluorescent dye-labeled PLGA microparticles in rats remained in the lumbar region for ≥7 days. In a rat model of neuropathic pain, i.t. coinjection of hydromorphone- and ketamine-loaded microparticles (each 1 mg) produced analgesia for 8 h only. Possible explanations include inadequate release of ketamine and/or hydromorphone into the spinal fluid, and/or insufficient ketamine loading to prevent development of analgesic tolerance to the released hydromorphone. As sub-analgesic doses of i.t. ketamine at 24-48 h intervals restored analgesia on each occasion, insufficient ketamine loading appears problematic. We will investigate these issues in future work.

Avaliação da analgesia pós-operatória da metadona, da cetamina ou da sua associação em gatas submetidas a ovariossalpingo-histerectomia

A prevenção e o controle da dor são componentes básicos para um procedimento anestésico adequado. Objetivou-se com este estudo avaliar a analgesia pós-operatória da cetamina, em dose subanestésica, da metadona e da associação de ambas pela via intramuscular em felinos. Foram utilizadas 24 gatas, hígidas, submetidas à ovariossalpingo-histerectomia eletiva. No dia anterior ao início do estudo, os animais foram anestesiados para colocação de cateter na veia jugular, para posterior coleta de sangue para mensuração da concentração sérica do cortisol. No dia do experimento, os animais foram alocados aleatoriamente em três grupos (n=oito), os quais receberam cetamina (GC), na dose de 0,5mg/kg; ou metadona (GM), na dose de 0,3mg/kg; ou cetamina e metadona (GCM), nas doses de 0,5mg/kg e 0,3mg/kg, respectivamente, todos pela via intramuscular. Todos os grupos receberam os fármacos 20 minutos antes da indução anestésica, a qual foi realizada com propofol, e a manutenção com isoflurano. Os parâmetros avaliados foram a mensuração do cortisol nos momentos M0 (basal - antes da cirurgia), M1(transoperatório), M2, M3, M4, M8, M12 e M24 (duas, três, quatro, oito, 12 e 24 horas após o término da cirurgia),e a do escore de dor por meio da escala multidimensional de dor aguda em felinos nos momentos M0, M2, M3, M4, M8, M12 e M24. Os valores de cortisol foram maiores no GC em comparação ao GM e ao GCM em M2 e M3. Os escores de dor foram maiores no GC nos momentos M2 e M3 em comparação ao GM e ao GCM, respectivamente. No somatório de pontos, no M2, o GC apresentou valores maiores que o GM e o GCM, e, no M4, o GC obteve valores maiores que o GCM. Em relação ao número de resgates no pós-operatório no GC, 8/8 dos animais necessitaram de resgate, no GM 5/8 e no GCM 3/8. Conclui-se que a associação de metadona e cetamina em gatas submetidas à OSH eletiva promove analgesia pós-operatória adequada e, assim, reduz o requerimento de analgésicos no período pós-operatório.

Does the Method and Timing of Intravenous Ketamine Administration Affect Postoperative Morphine Requirement After Major Abdominal Surgery?

OBJECTIVE

Single intravenous bolus administration and postoperative or perioperative infusions are the most preferred methods of ketamine. Nevertheless, there is no clear explanation on the ideal ketamine administration method. In this study, we aimed to compare the effects of the most common ketamine administration methods and administration time on postoperative opioid consumption.

METHODS

Fifty-two patients undergoing colectomy for colon cancer were randomly assigned into four groups. Group 1 was the control group. Group 2 received only a single intravenous bolus dose of 0.5 mg kg(-1) ketamine at induction. Group 3 received 0.5 mg kg(-1) intravenous ketamine bolus at induction and perioperative ketamine infusion at a rate of 0.25 mg kg(-1) h(-1). Group 4 received a bolus of 0.5 mg kg(-1) intravenous ketamine at induction and perioperative and postoperative ketamine infusion at a rate of 0.25 mg kg(-1) h(-1). Postoperatively, visual analogue scale pain scores, side effects, and morphine consumption were recorded.

RESULTS

There was no statistically significant difference in postoperative pain scores. Total morphine consumption was found to be significantly lower in Group 4 compared to the other groups (p=0.03, p=0.004, p=0.03, respectively). During the 1(st), 2(nd), and 4(th) hours in the postoperative period, patient-controlled analgesia morphine consumption was significantly lower in Group 4 compared to the control group (p<0.01).

CONCLUSION

Preoperative single-bolus dose or intraoperative low-dose ketamine infusion does not decrease postoperative morphine consumption; however, per- and postoperative 48-hour ketamine infusion has a significant effect in decreasing morphine consumption without decreasing the incidence of side effects in patients undergoing major abdominal surgery.

Multimodal therapy in perioperative analgesia

This article reviews the current evidence for multimodal analgesic options for common surgical procedures. As perioperative physicians, we have come a long way from using only opioids for postoperative pain to combinations of acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), selective Cyclo-oxygenase (COX-2) inhibitors, local anesthetics, N-methyl-d-aspartate (NMDA) receptor antagonists, and regional anesthetics. As discussed in this article, many of these agents have decreased narcotic requirements, improved patient satisfaction, and decreased postanesthesia care unit (PACU) times, as well as morbidity in the perioperative period.