Peri-operative intravenous administration of magnesium sulphate and postoperative pain: a meta-analysis

Efficacy of nonopioid analgesics and adjuvants in multimodal analgesia for reducing postoperative opioid consumption and complications in obesity: a systematic review and network meta-analysis

BACKGROUND

Managing postoperative pain in patients with obesity is challenging. Although multimodal analgesia has proved effective for pain relief, the specific impacts of different nonopioid i.v. analgesics and adjuvants on these patients are not well-defined. This study aims to assess the effectiveness of nonsteroidal antiinflammatory drugs, paracetamol, ketamine, α-2 adrenergic receptor agonists, lidocaine, magnesium, and oral gabapentinoids in reducing perioperative opioid consumption and, secondarily, in mitigating the occurrence of general and postoperative pulmonary complications (POPCs), nausea, vomiting, PACU length of stay (LOS), and hospital LOS among surgical patients with obesity.

METHODS

A systematic review and network meta-analysis was performed. PubMed, Scopus, Web of Science, CINAHL, and EMBASE were searched. Only English-language RCTs investigating the use of nonopioid analgesics and adjuvants in adult surgical patients with obesity were included. The quality of evidence and certainty were assessed using the RoB 2 tool and GRADE framework, respectively.

RESULTS

In total, 37 RCTs involving 3602 patients were included in the quantitative analysis. Compared with placebo/no intervention or a comparator, dexmedetomidine, ketamine, lidocaine, magnesium, and gabapentin significantly reduced postoperative opioid consumption after surgery. Ketamine/esketamine also significantly reduced POPCs. Ibuprofen, dexmedetomidine, and lidocaine significantly reduced postoperative nausea, whereas dexmedetomidine, either alone or combined with pregabalin, and lidocaine reduced postoperative vomiting. Dexmedetomidine significantly reduced PACU LOS, whereas both paracetamol and lidocaine reduced hospital LOS.

CONCLUSIONS

Intravenous nonopioid analgesics and adjuvants are crucial in multimodal anaesthesia, reducing opioid consumption and enhancing postoperative care in adult surgical patients with obesity.

SYSTEMATIC REVIEW PROTOCOL

CRD42023399373 (PROSPERO).

Magnesium Sulfate Versus Lidocaine as an Adjunct for Renal Colic in the Emergency Department: A Randomized, Double-Blind Controlled Trial

STUDY OBJECTIVE

We wished to determine whether the addition of magnesium sulfate (MgSO4) or lidocaine to diclofenac could improve the analgesic efficacy in emergency department (ED) patients with acute renal colic.

METHODS

In this prospective, double-blinded, randomized controlled trial of patients aged 18 to 65 years with suspected acute renal colic, we randomized them to receive 75 mg intramuscular (IM) diclofenac and then intravenous (IV) MgSO4, lidocaine, or saline solution control. Subjects reported their pain using a numerical rating scale (NRS) before drug administration and then 5, 10, 20, 30, 60, and 90 minutes afterwards. Our primary outcome was the proportion of participants achieving at least a 50% reduction in the NRS score 30 minutes after drug administration.

RESULTS

We enrolled 280 patients in each group. A 50% or greater reduction in the NRS score at 30 minutes occurred in 227 (81.7%) patients in the MgSO4 group, 204 (72.9%) in the lidocaine group, and 201 (71.8%) in the control group, with significant differences between MgSO4 and lidocaine (8.8%, 95% confidence interval [CI] [1.89 to 15.7], P=.013) and between MgSO4 and control (9.9%, 95% CI [2.95 to 16.84], P=.004). Despite this, differences between all groups at every time point were below the accepted 1.3 threshold for clinical importance. There were no observed differences between groups in the frequency of rescue analgesics and return visits to the ED for renal colic. There were more adverse events, although minor, in the MgSO4 group.

CONCLUSION

Adding intravenous MgSO4, but not lidocaine, to IM diclofenac offered superior pain relief but at levels below accepted thresholds for clinical importance.

Prolonged magnesium sulfate infusion as adjuvant analgesia in postoperative transplant patients in the pediatric ICU: Preliminary results of a feasibility study

The opioid crisis has emphasized identification of opioid-sparing analgesics. This study was designed as a prospective trial with retrospective control group to determine feasibility for implementing a high-dose prolonged magnesium sulfate infusion for adjuvant analgesia in the pediatric intensive care unit. Approval was granted for study of children receiving total pancreatectomy with islet cell autotransplantation and liver transplantation ages 3-18 years. Study exclusions were pregnancy, neuromuscular disease, hypersensitivity, preoperative creatinine >1.5 times upper limit normal, arrhythmia or pacemaker presence, and clinician concern. Eleven patients were enrolled between January 2020 and December 2022. Magnesium sulfate bolus (50 mg/kg) followed by intravenous infusion (15 mg/kg/h) was initiated in the operating room and extended postoperatively (maximum 48 h). Serum magnesium levels were monitored serially. To prioritize safety, infusion dose was decreased by 5 mg/kg/h for levels greater than 3.5 mg/dL. Clinical team otherwise followed standard multimodal pain practice. Primary outcome was oral morphine equivalent per kg per day during intensive care course (maximum 7 days). Secondary outcomes focused primarily on magnesium safety, including hemodynamic variables, electrolyte variables, respiratory support, and opioid-related side effects. There were no serious adverse events. Treatment group trended toward slightly higher intravenous fluid requirement (~1 bolus), however no increase in blood product. Treatment and control groups were otherwise comparable in targeted outcomes and overall adverse event profile. Use of a high-dose magnesium sulfate infusion protocol for analgesic postoperative use in select transplant recipients appears feasible for continued optimization of study in the PICU.

Intraoperative magnesium sulfate is not associated with improved pain control after urologic procedures

OBJECTIVE

To evaluate effects of intraoperative magnesium sulfate infusion on pain control and analgesic use in the postanesthesia care unit (PACU).

METHODS

This is a retrospective review of patients undergoing robot-assisted radical prostatectomy (RARP) and endoscopic procedures of the bladder, prostate, and urethra from 2/2021 to 12/2021. Patients receiving Mg infusion (Mg group) received an intravenous 2-g bolus of Mg at anesthesia induction, followed by infusion of 1 g/h until procedure end. Outcomes were compared with patients who underwent similar procedures during this timeframe without Mg (Control). Endpoints were use of anticholinergic (AC) and belladonna and opium suppositories (BO), maximum pain score, and morphine milligram equivalents (MME) in PACU.

RESULTS

There were 182 patients, with 89 (48.9%) patients in the Mg group and 93 (51.1%) in the Control. Significantly, fewer patients in the Mg group were given AC/BO in PACU (9.0% vs. 21.7%, p = 0.02), with odds of using AC/BO which was 0.36 (95% CI 0.14, 0.83). No differences were found in pain score (p = 0.62) or MME administration (p = 0.94). In subgroup univariate analysis, only those who underwent bladder procedures had a significant difference in use of AC/BO (9.5% vs. 30.2%; p = 0.02). Across all surgeries, Mg infusion was associated with decreased use of AC/BO in the PACU (OR 0.34, p = 0.02); however, stratifying by procedure type did not find a difference in AC/BO use postoperatively.

CONCLUSION

Intravenous infusion of magnesium was found to decrease use of AC/BO in the PACU; however, this significance was lost after multivariable analysis stratifying by procedure type.

Adjuvant Analgesics in Acute Pain - Evaluation of Efficacy

PURPOSE OF THE REVIEW

Acute postoperative pain impacts a significant number of patients and is associated with various complications, such as a higher occurrence of chronic postsurgical pain as well as increased morbidity and mortality.

RECENT FINDINGS

Opioids are often used to manage severe pain, but they come with serious adverse effects, such as sedation, respiratory depression, postoperative nausea and vomiting, and impaired bowel function. Therefore, most enhanced recovery after surgery protocols promote multimodal analgesia, which includes adjuvant analgesics, to provide optimal pain control. In this article, we aim to offer a comprehensive review of the contemporary literature on adjuvant analgesics in the management of acute pain, especially in the perioperative setting. Adjuvant analgesics have proven efficacy in treating postoperative pain and reducing need for opioids. While ketamine is an established option for opioid-dependent patients, magnesium and α2-agonists have, in addition to their analgetic effect, the potential to attenuate hemodynamic responses, which make them especially useful in painful laparoscopic procedures. Furthermore, α2-agonists and dexamethasone can extend the analgesic effect of regional anesthesia techniques. However, findings for lidocaine remain inconclusive.

Influence of Intravenous Magnesium Sulfate Infusion on the Subjective Postoperative Quality of Recovery: A Meta-Analysis of Randomized Controlled Trials

This meta-analysis investigated the effects of intravenous magnesium sulfate on the postoperative recovery quality, as assessed using the Quality of Recovery (QoR) questionnaire, in adult surgical patients. Seven randomized controlled trials involving 622 patients were included. Compared with the placebo, magnesium sulfate significantly improved the global QoR score on postoperative day 1 (standardized mean difference [SMD]: 1.24; 95% confidence interval: 0.70-1.78; p < 0.00001). It also enhanced specific QoR dimensions, with substantial effects on pain (SMD: 1, p < 0.00001) and physical comfort (SMD: 0.85, p < 0.0001), a moderate effect on emotional state (SMD: 0.65, p = 0.002), and small improvements in physical independence (SMD: 0.43, p < 0.00001) and psychological support (SMD: 0.37, p < 0.0001). In addition, magnesium sulfate reduced the intraoperative opioid consumption (SMD: -0.66, p < 0.0001), postoperative pain severity, and the incidence of postoperative nausea and vomiting (risk ratio: 0.48, p = 0.008). The extubation times were unaffected, whereas the post-anesthesia care unit stay was slightly prolonged. These findings highlight the potential of magnesium sulfate as a valuable adjunct for multimodal analgesia and enhanced recovery. Future studies should aim to elucidate the optimal dosing strategies, timing of administration, and specific surgical populations that may derive maximum benefits.

Unravelling the analgesic effects of perioperative magnesium in general abdominal surgery: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Prior research has established the effectiveness of magnesium in relieving postoperative pain. This article aims to evaluate magnesium sulfate for perioperative analgesia in adults undergoing general abdominal surgery under general anesthesia.

OBJECTIVE

The primary aim was to assess pain scores at 6 and 24 hours postoperatively in patients receiving magnesium sulfate vs. the control group. Secondary outcomes were postoperative opioid consumption, perioperative complications, and time to rescue analgesia.

METHODS

A comprehensive database search identified studies comparing magnesium sulfate with control in adults undergoing general anesthesia for general abdominal surgery. Using random-effects models, data were presented as mean ± Standard Deviation (SD) or Odds Ratios (OR) with corresponding 95% Confidence Intervals (95% CI). A two-sided p-value < 0.05 was considered statistically significant.

RESULTS

In total, 31 studies involving 1762 participants met the inclusion criteria. The magnesium group showed significantly lower postoperative pain scores at both early (within six hours) and late (up to 24 hours) time points compared to the control group. The early mean score was 3.1 ± 1.4 vs. 4.2 ± 2.3, and the late mean score was 2.3 ± 1.1 vs. 2.7 ± 1.5, resulting in an overall Mean Difference (MD) of -0.72; 95% CI -0.99, -0.44; p < 0.00001. The magnesium group was associated with lower rates of postoperative opioid consumption and shivering and had a longer time to first analgesia administration compared to the saline control group.

CONCLUSION

Magnesium sulfate administration was linked to reduced postoperative pain and opioid consumption following general abdominal surgery.

The 2023 WSES guidelines on the management of trauma in elderly and frail patients

BACKGROUND

The trauma mortality rate is higher in the elderly compared with younger patients. Ageing is associated with physiological changes in multiple systems and correlated with frailty. Frailty is a risk factor for mortality in elderly trauma patients. We aim to provide evidence-based guidelines for the management of geriatric trauma patients to improve it and reduce futile procedures.

METHODS

Six working groups of expert acute care and trauma surgeons reviewed extensively the literature according to the topic and the PICO question assigned. Statements and recommendations were assessed according to the GRADE methodology and approved by a consensus of experts in the field at the 10th international congress of the WSES in 2023.

RESULTS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage, including drug history, frailty assessment, nutritional status, and early activation of trauma protocol to improve outcomes. Acute trauma pain in the elderly has to be managed in a multimodal analgesic approach, to avoid side effects of opioid use. Antibiotic prophylaxis is recommended in penetrating (abdominal, thoracic) trauma, in severely burned and in open fractures elderly patients to decrease septic complications. Antibiotics are not recommended in blunt trauma in the absence of signs of sepsis and septic shock. Venous thromboembolism prophylaxis with LMWH or UFH should be administrated as soon as possible in high and moderate-risk elderly trauma patients according to the renal function, weight of the patient and bleeding risk. A palliative care team should be involved as soon as possible to discuss the end of life in a multidisciplinary approach considering the patient's directives, family feelings and representatives' desires, and all decisions should be shared.

CONCLUSIONS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage based on assessing frailty and early activation of trauma protocol to improve outcomes. Geriatric Intensive Care Units are needed to care for elderly and frail trauma patients in a multidisciplinary approach to decrease mortality and improve outcomes.

Single-bolus injection of local anesthetic, with or without continuous infusion, for interscalene brachial plexus block in the setting of multimodal analgesia: a randomized controlled unblinded trial

INTRODUCTION

Previous trials favored a continuous interscalene brachial plexus block over a single injection for major shoulder surgery. However, these trials did not administer a multimodal analgesic regimen. This randomized, controlled unblinded trial tested the hypothesis that a continuous infusion of local anesthetic for an interscalene brachial plexus block still provides superior analgesia after major shoulder surgery when compared with a single injection in the setting of multimodal analgesia, inclusive of intravenous dexamethasone, magnesium, acetaminophen and ketorolac.

METHODS

Sixty patients undergoing shoulder arthroplasty or arthroscopic rotator cuff repair were randomized to receive a bolus of ropivacaine 0.5%, 20 mL, with or without a continuous infusion of ropivacaine 0.2% 4-8 mL/hour, for an interscalene brachial plexus block. Patients were provided with intravenous morphine patient-controlled analgesia. The primary outcome was cumulative intravenous morphine consumption at 24 hours postoperatively. Secondary outcomes included pain scores at rest and on movement, and functional outcomes, measured over 48 hours after surgery.

RESULTS

Median (IQR) cumulative intravenous morphine consumption at 24 hours postoperatively was 10 mg (4-24) in the continuous infusion group and 14 mg (8-26) in the single injection group (p=0.74). No significant between-group differences were found for any of the secondary outcomes.

CONCLUSIONS

A continuous infusion of local anesthetic for an interscalene brachial plexus block does not provide superior analgesia after major shoulder surgery when compared with a single injection in the setting of multimodal analgesia, inclusive of intravenous dexamethasone, magnesium, acetaminophen and ketorolac. The findings of this study are limited by performance and detection biases.

TRIAL REGISTRATION NUMBER

NCT04394130.

Femoral vs sciatic nerve block to provide analgesia after medial open wedge high tibial osteotomy in the setting of multimodal analgesia: A randomized, controlled, single-blinded trial

STUDY OBJECTIVE

Medial open wedge high tibial osteotomy (MOW HTO) is associated with moderate to severe postoperative pain. The proximal part of the tibia is innervated by branches from the femoral nerve anteriorly and the sciatic nerve posteriorly. There is a paucity of information regarding the optimal peripheral nerve block for postoperative analgesia with minimal impact on motor function. This study tested the hypothesis that a femoral nerve block provides superior analgesia to a sciatic nerve block after MOW HTO in the setting of multimodal analgesia.

DESIGN

Randomized controlled single-blind trial.

SETTING

Operating room, postoperative recovery area and ward, up to 6 postoperative months.

PATIENTS

Fifty patients undergoing MOW HTO.

INTERVENTIONS

Interventions were femoral or sciatic nerve block under ultrasound guidance. For each intervention, a total of 100 mg of ropivacaine was injected. Postoperative pain treatment followed a pre-defined protocol with intravenous patient-controlled analgesia of morphine, paracetamol, and ibuprofen.

MEASUREMENTS

The primary outcome was intravenous morphine consumption at 24 h postoperatively. Secondary outcomes included rest and dynamic pain scores (on a numeric rating scale out of 10) at 2, 24 and 48 h postoperatively. Functional outcomes included the Short Form-12, Knee injury and Osteoarthritis Outcome Score, and International Knee Documentation Committee (IKDC) scores measured at 6 months postoperatively.

MAIN RESULTS

Mean [95% confidence interval] i.v. morphine consumption at 24 postoperative hours were 24 mg [15 mg,33 mg] in the femoral nerve block group and 24 mg [16 mg,32 mg] in the sciatic nerve block group (p = 0.98). There were no significant differences in the secondary outcomes between groups.

CONCLUSIONS

This trial failed to demonstrate that a femoral nerve block provides superior analgesia to a sciatic nerve block after MOW HTO under general anesthesia in the setting of multimodal analgesia. There was no significant difference in quality of life and functional outcomes at 6 months postoperatively between groups. Trial registry number:Clinicaltrials.com - NCT05728294; Kofam.ch - SNCTP000003048 | BASEC2018-01774.

Non-Opioid Analgesics and Adjuvants after Surgery in Adults with Obesity: Systematic Review with Network Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Managing postoperative pain in patients with obesity is challenging. Although using a combination of pain relief methods is recommended for these patients, the true effectiveness of various intravenous non-opioid analgesics and adjuvants in multimodal anesthesia needs to be better defined. Methods: A systematic review and network meta-analysis was performed to evaluate the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, ketamine, α-2 agonists, lidocaine, magnesium, and oral gabapentinoids in adult surgical patients with obesity. The analysis aimed to compare these treatments to a placebo/no treatment or alternative analgesics, with a primary focus on postoperative pain and secondary endpoints including rescue analgesia, postoperative nausea and vomiting (PONV), and recovery quality. English-language randomized controlled trials across PubMed, Scopus, Web of Science, CINAHL, and EMBASE were considered. Quality and evidence certainty were assessed with the RoB 2 tool and GRADE, and data was analyzed with R software. Results: NSAIDs, along with acetaminophen, lidocaine, α-2 agonists, ketamine, and oral gabapentinoids, effectively reduce early postoperative pain. NSAIDs, particularly ibuprofen, as well as acetaminophen, ketamine, and lidocaine, also show benefits in later postoperative stages. Intravenous non-opioid analgesics and adjuvants show some degree of benefit in reducing PONV and the need for rescue analgesic therapy when using α-2 agonists alone or combined with oral gabapentinoids, notably decreasing the likelihood of PONV. Ketamine, lidocaine, and α-2 agonists are shown to enhance postoperative recovery and care quality. Conclusions: Intravenous non-opioid analgesics and adjuvants are valuable in multimodal anesthesia for pain management in adult surgical patients suffering from obesity.

Engineered MgO nanoparticles for cartilage-bone synergistic therapy

The emerging therapeutic strategies for osteoarthritis (OA) are shifting toward comprehensive approaches that target periarticular tissues, involving both cartilage and subchondral bone. This shift drives the development of single-component therapeutics capable of acting on multiple tissues and cells. Magnesium, an element essential for maintaining skeletal health, shows promise in treating OA. However, the precise effects of magnesium on cartilage and subchondral bone are not yet clear. Here, we investigated the therapeutic effect of Mg2+ on OA, unveiling its protective effects on both cartilage and bone at the cellular and animal levels. The beneficial effect on the cartilage-bone interaction is primarily mediated by the PI3K/AKT pathway. In addition, we developed poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with nano-magnesium oxide modified with stearic acid (SA), MgO&SA@PLGA, for intra-articular injection. These microspheres demonstrated remarkable efficacy in alleviating OA in rat models, highlighting their translational potential in clinical applications.

The analgesic effects of magnesium in veterinary patients: a qualitative evidence synthesis

OBJECTIVE

To perform a qualitative evaluation of the analgesic effects of magnesium in domestic animals, including its anaesthetic sparing effects.

STUDY DESIGN

All database searches were made using PubMed and Google Scholar. Studies published after 1990, evaluating the use of magnesium and reporting information on analgesia, in dogs, cats, horses, cows, goats and sheep were selected (last search in August 2023). A reference check in the selected papers was performed to identify any study which was omitted. The CERQual (Confidence in Evidence from Reviews of Qualitative research) approach was used to assess confidence and analyse the evidence.

RESULTS

A total of 20 studies relevant to the analgesic effects of magnesium in veterinary patients and two reviews were included. All were published after 2006. Of the 20, five studies provided information about analgesia in the postoperative period in dogs with heterogenous results. Magnesium added epidurally increased the duration of the sensory block in several species. Motor block was also observed when added to spinal analgesia. Results regarding volatile agents sparing effect were conflicting. Occasional moderate adverse effects were reported in dogs, such as nausea and vomiting, when administered as a bolus in conscious animals, and hypotension when administered intraperitoneally. Collapse was reported in horses after epidural administration.

CONCLUSIONS AND CLINICAL RELEVANCE

The evidence of an analgesic effect of magnesium in veterinary patients remains scarce considering the paucity and low quality of published data. Further research may be helpful to establish the efficacy and indications of magnesium in multimodal analgesia in animals.

Effect of intravenous magnesium on post-operative pain following Latarjet shoulder reconstruction

Background

Single injection ropivacaine interscalene anesthesia (ISA) is frequently used in Latarjet reconstruction to enhance post-operative analgesia. A potential limitation is the occurrence of severe rebound pain on block resolution. We investigated the effect of intravenous magnesium on post-operative pain, particularly at the transition of block resolution to multimodal analgesia.

Methods

Elective patients (n = 40) having Latarjet open shoulder reconstruction were randomised to receive either intravenous magnesium sulphate 50 mg/kg (M) or normal saline (S) before induction. Post-operatively, a standardised analgesic regimen was used, and post-operative pain was recorded using a verbal numerical rating assessment (VNRA) score. Requirement for injected opioid analgesia was recorded.

Results

ISA provided longstanding analgesia in all patients with block duration slightly prolonged in the magnesium group (16.7(1.0) (S), 17.8(1.3) h (M), p = 0.049). Magnesium resulted in less rebound pain following ISA resolution (VNRA 4.0 (0.6) M, 6.2 (0.8) S, p = 0.03) and lower pain intensity at 24 h. Four patients had nausea and two required rescue opioid injection.

Conclusion

Magnesium before Latarjet surgery results in less rebound pain following ropivacaine block and improves post-operative analgesia. Magnesium may be indicated in major upper limb surgery, where significant pain intensity is anticipated.

Level of evidence

Treatment study; Randomised blinded; Level 2.

Duration of analgesia after forefoot surgery compared between an ankle and a sciatic nerve block at the popliteal crease: A randomised controlled single-blinded trial

BACKGROUND

Forefoot surgery is associated with severe postoperative pain. Ankle and sciatic nerve blocks provide satisfactory postoperative analgesia after forefoot surgery, but little is known on their respective duration of analgesia.

OBJECTIVE

This randomised controlled, single-blinded trial tested the hypothesis that after forefoot surgery in the setting of multimodal analgesia, an ankle block provides analgesia superior to that of a sciatic nerve block at the popliteal crease.

DESIGN

A randomised controlled study.

SETTING

A single centre study in a university hospital in Switzerland, from September 2018 to November 2022.

PATIENTS

From 91 patients scheduled for forefoot surgery, 60 met the inclusion criteria of which 56 completed the protocol and their data were available for analysis. Exclusion criteria were existing sciatic nerve deficit, pre-existing peripheral neuropathy, chronic pain diagnosis, pregnancy, or identified contraindications to peripheral nerve block.

INTERVENTION

Patients undergoing forefoot surgery were randomly allocated to either a multi-injection ankle block (partly under ultrasound guidance) or a sciatic nerve block at the popliteal crease (under ultrasound guidance) combined with a saphenous nerve block at the ankle. Patients in each group received a total of 30 ml of ropivacaine 0.5% and a multimodal analgesic regimen inclusive of dexamethasone, paracetamol, ketorolac then ibuprofen.

MAIN OUTCOME MEASURE

The primary outcome was duration of analgesia, defined as time to first morphine request.

RESULTS

Mean ± SD duration of analgesia was 15.4 ± 8.0 h in the ankle block group and 20.0 ± 10.3 h in the sciatic nerve block group ( P  = 0.32). Of note, 15 of 26 (58%) and 24 of 30 (80%) patients of the ankle and sciatic nerve block groups did not request any morphine ( P  = 0.09). Other secondary outcomes were similar between groups.

CONCLUSION

Compared with the ankle block, the sciatic nerve block at the popliteal crease does not provide a longer duration of analgesia in patients undergoing forefoot surgery in the setting of multimodal analgesia.

TRIAL REGISTRATION

Clinicaltrials.com identifier: NCT03683342.

Peri-operative management and analgesic strategy for a patient undergoing quadruple limb amputation

Inadequately managed amputation pain can contribute to postoperative morbidity and mortality. However, amputation pain can be challenging to manage due to its complex nature, with both central and peripheral nociceptive and neuropathic elements. Here, we present the case of a 47-year old man who developed irreversible ischaemic injuries to all four limbs following admission to intensive care with sepsis. He required quadruple amputation and we describe our approach to his peri-operative management including anaesthesia, invasive monitoring and the multi-modal approach to his peri-operative management using a combination of intravenous analgesics, bilateral brachial plexus nerve catheters and a combined spinal and epidural. The patient made a good recovery and was able to return home from a rehabilitation facility 12 months after the operation, able to undertake many tasks himself with the aid of prosthetics.

Pain Control for Sickle Cell Crisis, a Novel Approach? A Retrospective Study

Background and Objectives: Pain management poses a significant challenge for patients experiencing vaso-occlusive crisis (VOC) in sickle cell disease (SCD). While opioid therapy is highly effective, its efficacy can be impeded by undesirable side effects. Local regional anesthesia (LRA), involving the deposition of a perineural anesthetic, provides a nociceptive blockade, local vasodilation and reduces the inflammatory response. However, the effectiveness of this therapeutic approach for VOC in SCD patients has been rarely reported up to now. The objective of this study was to assess the effectiveness of a single-shot local regional anesthesia (LRA) in reducing pain and consequently enhancing the management of severe vaso-occlusive crisis (VOC) in adults with sickle cell disease (SCD) unresponsive to conventional analgesic therapy. Materials and Methods: We first collected consecutive episodes of VOC in critical care (ICU and emergency room) for six months in 2022 in a French University hospital with a large population of sickle cell patients in the West Indies population. We also performed a systematic review of the use of LRA in SCD. The primary outcome was defined using a numeric pain score (NPS) and/or percentage of change in opioid use. Results: We enrolled nine SCD adults (28 years old, 4 females) for ten episodes of VOC in whom LRA was used for pain management. Opioid reduction within the first 24 h post block was -75% (50 to 96%). Similarly, the NPS decreased from 9/10 pre-block to 0-1/10 post-block. Five studies, including one case series with three patients and four case reports, employed peripheral nerve blocks for regional anesthesia. In general, local regional anesthesia (LRA) exhibited a reduction in pain and symptoms, along with a decrease in opioid consumption post-procedure. Conclusions: LRA improves pain scores, reduces opioid consumption in SCD patients with refractory pain, and may mitigate opioid-related side effects while facilitating the transition to oral analgesics. Furthermore, LRA is a safe and effective procedure.

Pain in Colorectal Surgery: How Does It Occur and What Tools Do We Have for Treatment?

Pain is a complex entity with deleterious effects on the entire organism. Poorly controlled postoperative pain impacts the patient outcome, being associated with increased morbidity, inadequate quality of life and functional recovery. In the current surgical environment with less invasive surgical procedures increasingly being used and a trend towards rapid discharge home after surgery, we need to continuously re-evaluate analgesic strategies. We have performed a narrative review consisting of a description of the acute surgical pain anatomic pathways and the connection between pain and the surgical stress response followed by reviewing methods of multimodal analgesia in colorectal surgery found in recent literature data. We have described various regional analgesia techniques and drugs effective in pain treatment, emphasizing their advantages and concerns. We have also tried to identify present knowledge gaps requiring future research. Our review concludes that surgical pain has peculiarities that make its management complex, implying a consistent, multimodal approach aiming to block both peripheral and central pain pathways.

Adjuvants for balanced anesthesia in ambulatory surgery

Balanced anesthesia relies on the simultaneous administration of different drugs to attain an anesthetic state. The classic triad of anesthesia is a combination of a hypnotic, an analgesic, and a neuromuscular blocker. It is predominantly the analgesic pillar of this triad that became more and more supported by adjuvant therapy. The aim of this approach is to evolve into an opioid-sparing technique to cope with undesirable side effects of the opioids and is fueled by the opioid epidemic. The optimal strategy for balanced general anesthesia in ambulatory surgery must aim for a transition to a multimodal analgesic regimen dealing with acute postoperative pain and ideally reduce the most common adverse effects patients are faced with at home; sore throat, delayed awakening, memory disturbances, headache, nausea and vomiting, and negative behavioral changes. Over the years, this continuum of "multimodal general anesthesia" adopted many drugs with different modes of action. This review focuses on the most recent evidence on the different adjuvants that entered clinical practice and gives an overview of the different mechanisms of action, the potential as opioid-sparing or hypnotic-sparing drugs, and the applicability specifically in ambulatory surgery.

Pain Management at the End of Life in the Emergency Department: A Narrative Review of the Literature and a Practical Clinical Approach

Access to pain management is a fundamental human right for all people, including those who are at the end of life (EOL). In end-stage patients, severe and uncontrolled pain is a common cause of admission to the emergency department (ED), and its treatment is challenging due to its complex, often multifactorial genesis. The aim of this narrative review was to identify the available literature on the management of severe EOL pain in the ED. The MEDLINE, SCOPUS, EMBASE, and CENTRAL databases were searched from inception to 1 April 2023 including randomised controlled trials, observational studies, systemic or narrative reviews, case reports, and guidelines on the management of EOL pain in the ED. A total of 532 articles were identified, and 9 articles were included (5 narrative reviews, 2 retrospective studies, and 2 prospective studies). Included studies were heterogeneous on the scales used and recommended for pain assessment and the recommended treatments. No study provided evidence for a better approach for EOL patients with pain in the ED. We provide a narrative summary of the findings and a review of the management of EOL pain in clinical practice, including (i) the identification of the EOL patients and unmet palliative care needs, (ii) a multidimensional, patient-centred assessment of the type and severity of pain, (iii) a multidisciplinary approach to the management of end-of-life pain, including an overview of non-pharmacological and pharmacological techniques; and (iv) the management of special situations, including rapid acute deterioration of chronic pain, breakthrough pain, and sedative palliation.

Is intravenous magnesium sulphate a suitable adjuvant in postoperative pain management? - A critical and systematic review of methodology in randomized controlled trials

A growing worldwide focus on opioid-free anaesthesia entails multimodal analgesic strategies involving non-opioids such as magnesium sulphate (MgSO4). Several systematic reviews have concluded there is beneficial analgesic effect of MgSO4 administration but do not take considerable heterogeneity among the studies into consideration. Medical literature published until June 2021 was searched in PubMed/Medline, Embase, Central and Web of Science: The final search yielded a total of 5,672 articles. We included only randomised controlled trials assessing the effect of intravenous MgSO4 on opioid consumption and acute postoperative pain when compared to either placebo or standardized analgesic treatment. The primary aim was to compare the homogeneity of essential variables and confounders. A post-hoc meta-analysis demonstrated a reduction in both postoperative morphine consumption (-6.12 mg) and pain score (-12.32 VAS points) in favour of the MgSO4-groups. Data for meta-analysis was missing from 19 studies (45%) on morphine consumption and 29 studies (69%) for pain score, the majority of which reports no effect for either morphine consumption or pain score. The calculated heterogeneity among the included studies was considerable for both outcomes; I 2=91% for morphine consumption and I 2=96% for pain score. Although we found a per se reduction in opioid consumption and pain score, methodological heterogeneity and clinical shortcomings of pre-, intra-, and post anaesthetic data precludes conclusions on clinical importance of intraoperative intravenous MgSO4. In addition, the reduction is likely less than what can be gained from using standardized analgesic treatment.

Effects of magnesium sulfate on periarticular infiltration analgesia in total knee arthroplasty: a prospective, double-blind, randomized controlled trial

BACKGROUND

To investigate whether adding magnesium sulfate to a periarticular infiltration analgesia (PIA) cocktail could improve pain control and functional outcomes in patients undergoing total knee arthroplasty (TKA).

METHODS

Ninety patients were randomly assigned to the magnesium sulfate and control groups, with 45 patients in each group. In the magnesium sulfate group, patients were given a periarticular infusion of a cocktail of analgesics consisting of epinephrine, ropivacaine, magnesium sulfate, and dexamethasone. The control group received no magnesium sulfate. The primary outcomes consisted of visual analogue scale (VAS) pain scores, postoperative morphine hydrochloride consumption for rescue analgesia, and time to first rescue analgesia. Secondary outcomes were postoperative inflammatory biomarkers (IL-6 and CRP), postoperative length of stay, and knee functional recovery (assessed by knee range of motion, quadriceps strength, daily mobilization distance, and time to first straight-leg raising). Tertiary outcomes included the postoperative swelling ratio and complication rates.

RESULTS

Within 24 h of surgery, patients in the magnesium sulfate group had markedly lower VAS pain scores during motion and at rest. After the addition of magnesium sulfate, the analgesic effect was dramatically prolonged, leading to a reduction in morphine dosage within 24 h and the total morphine dosage postoperatively. Postoperative inflammatory biomarker levels were significantly reduced in the magnesium sulfate group compared with the control. There were no considerable differences between the groups in terms of the postoperative length of stay and knee functional recovery. Both groups had similar postoperative swelling ratios and incidences of complications.

CONCLUSIONS

The addition of magnesium sulfate to the analgesic cocktail for PIA can prolong postoperative analgesia, decrease the consumption of opioids, and effectively alleviate early postoperative pain after TKA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200056549. Registered on 7 February 2022, https://www.chictr.org.cn/showproj.aspx?proj=151489 .

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.

Evaluation of magnesium sulfate as an adjuvant in sub-Tenon anesthesia for cataract surgery: A prospective, randomized controlled trial

Purpose

To evaluate the efficacy, safety, and satisfaction for the use of adjuvant; magnesium sulfate (MgSO4) in sub-Tenon anesthesia for cataract surgery.

Methods

This single centered randomized, double blind trial was held in 2021 after approval of ethical committee at the Eye Hospital, Riyadh, Saudi Arabia. Cataract patients to be operated using local anesthesia were randomly assigned to two groups; Group magnesium sulfate (MS) received 50 mg/0.5 ml of magnesium sulfate and Group normal saline (NS) received 0.5 ml of normal saline added to the standard mixture, respectively. Absence of eyelid dropping and akinesia of the globe at different time after anesthesia were considered as ineffective anesthesia. The age and sex-adjusted generalized estimating equation (GEE) analysis was carried out. Complications, patient's and surgeon's satisfaction were also compared.

Results

Each group had 100 cataract patients. Effectiveness of block was not significantly different in two groups (adjusted odds ratio, 0.90; 95% confidence interval [CI], 0.62, 1.31; P = 0.594). The likelihood of "no eye-opening" significantly increased with time (adjusted odds ratio, 1.26; 95% CI, 1.18-1.34; P < 0.001). Subconjunctival bleeding was significantly higher in the MS versus NS Group (36 of 98 [36.7%] vs. 11 of 102 [10.8%], P < 0.001). Chemosis was not significantly different between the groups (P = 0.95). Patient's satisfaction score was very good (9/10) but slightly higher in NS group than MS (P = 0.001) while surgeon's satisfaction score was similar in both groups (P = 0.149).

Conclusions

Although safe, adding 50 mg of magnesium sulfate did not improve the effect of sub-Tenon anesthesia for cataract surgery. Risk of subconjunctival bleeding was higher in cataract patients operated using MgSO4 compared to those managed with the conventional sub-Tenon anesthetic.

Sensory block duration after spinal anaesthesia supplemented with intravenous dexamethasone: a randomised controlled double-blinded trial

BACKGROUND

Intravenous dexamethasone prolongs duration of analgesia or sensory block after injection of local anaesthetics close to peripheral nerves by an average of 8 h. Uncertainty remains on the potential increase in the duration of sensory block after spinal anaesthesia. The objective of this randomised controlled double-blinded trial was to investigate whether dexamethasone i.v. prolongs the sensory block of spinal anaesthesia with bupivacaine when compared with a control group.

METHODS

Of 50 patients undergoing lower limb osteoarticular surgery under spinal anaesthesia with isobaric bupivacaine 15 mg i.t. with morphine 100 μg i.t. were randomised to receive either dexamethasone 0.15 mg kg^-1 i.v. or normal saline 3 ml i.v. The primary outcome was duration of sensory block defined as the time elapsed between injection of the local anaesthetic in the intrathecal space and the regression of sensory block by two dermatomes compared with the highest dermatome blocked. Secondary outcomes included intravenous morphine consumption, pain scores at rest and on movement, postoperative nausea and vomiting, and blood glucose at 2, 24, and 48 h.

RESULTS

Median duration of sensory block was 135 (105-225) min in the dexamethasone group and 158 (135-240 min) in the control group (P=0.19). Patients in the dexamethasone group received less morphine at 24 h, had significantly less postoperative nausea and vomiting at 2 h and 24 h, and had increased blood glucose at 24 h. Other secondary outcomes were similar between groups.

CONCLUSION

Intravenous dexamethasone did not prolong the sensory block of spinal anaesthesia with isobaric bupivacaine. However, it reduced morphine consumption and rate of postoperative nausea and vomiting at 24 h, at the expense of an increased blood glucose.

CLINICAL TRIAL REGISTRATION

NCT03527576 (Clinicaltrials.gov).

Comparison of the Sedative Effect of Ketamine, Magnesium Sulfate, and Propofol in Patients Undergoing Upper Gastrointestinal Endoscopy: Double-Blinded Randomized Clinical Trial

BACKGROUND

Endoscopy provides valuable diagnostic information and intervention therapies for gastroenterologists. Therefore, various drugs have been used to induce sedation in patients undergoing endoscopy, whereas none have been considered preferred by endoscopists. In the current study, we decided to use the combination of magnesium sulfate, ketamine, and their synergistic effects for creating partial analgesia to increase the satisfaction of endoscopists and patients.

METHODS

This study is a Double-Blind Randomized Clinical Trial that investigates the sedative effect of ketamine, magnesium sulfate, and propofol in endoscopy. Patients were selected from individuals over 12 years old and with American Society of Anesthesia (ASA) physical status I or II. The study was performed on 210 patients classified as ASA (I have no underlying disease) or II (with underlying controlled disease). The whole group was relieved of pain through sedation according to Ramsay criteria, satisfaction with the operation, duration, recovery, nausea and vomiting, hypotension, and decreased oxygen saturation were compared.

RESULTS

A total of 155 patients were enrolled in our study, including 51 patients (midazolam and propofol), 55 patients (midazolam and ketamine), and 49 patients (midazolam and ketamine and magnesium). The results showed that preoperative heart rate, intraoperative systolic blood pressure, intraoperative diastolic blood pressure, postoperative heart rate, postoperative systolic blood pressure, and postoperative heart rate were significantly different between the groups.

CONCLUSION

The satisfaction of the endoscopic was achieved to a great extent, mainly in the group receiving midazolam and propofol and in the group receiving midazolam and ketamine. In most cases, the satisfaction of the endoscopic was acceptable, and the low satisfaction of the endoscopic was more in the group receiving midazolam. Ketamine and magnesium were observed. The two compounds midazolam-ketamine, and midazolam-propofol, have a more favorable effect than the combination of midazolam, ketamine, and magnesium.

Alternatives to remifentanil for the analgesic component of total intravenous anaesthesia: a narrative review

Propfol-remifentanil-based total intravenous anaesthesia has dominated recent clinical practice due to its favourable pharmacokinetic profile. Interruption in remifentanil supply has presented an opportunity to diversify or even avoid the use of opioids and consider adjuncts to propofol-based total intravenous anaesthesia. Propofol, while a potent hypnotic, is not an effective analgesic. The administration of opioids, along with other adjuncts such as α-2 adrenoceptor agonists, magnesium, lidocaine, ketamine and nitrous oxide provide surgical anaesthesia and avoids large doses of propofol being required. We provide an overview of both target-control and manual infusion regimes for the alternative opioids: alfentanil, sufentanil and fentanyl. The optimal combination of hypnotic-opioid dose, titration sequence and anticipated additional postoperative analgesia required depend on the chosen combination. In addition, we include a brief discussion on the role of non-opioid adjuncts in total intravenous anaesthesia, suggested doses and expected reduction in propofol dose.

Intravenous Versus Wetting Solution Magnesium Sulphate to Counteract Epinephrine Cardiac Adverse Events in Abdominal Liposuction: A Randomized Controlled Trial

Background

The increased frequency of liposuction has resulted in more complications being reported. Adding epinephrine to the wetting solution could induce some cardiac adverse effects, some of which may be fatal. For instance, magnesium sulfate (MgSO₄) is known for its cardioprotective effects.

Objectives

This study aimed to evaluate the efficacy of intravenous (IV) versus wetting solution containing MgSO₄ in decreasing such cardiac adverse events during abdominal liposuction.

Methods

This randomized controlled study included 129 adult cases undergoing abdominal liposuction under general anesthesia. The participants were divided into 3 groups: Group I (control group) was only subjected to the injection of the wetting fluid (1 mL 1/1000 epinephrine added to every 1000 mL of normal saline), group II was subjected to IV MgSO₄ (40 mg/kg over 1 minute) at the same time of installing the wetting solution, and group III was subjected to MgSO₄ (40 mg/kg) added to the wetting solution.

Results

Intraoperative isoflurane consumption, intraoperative heart rate (HR), mean arterial pressure (MAP), and postoperative pain scores were significantly lower in the MgSO₄ groups (groups II and III) than group I. Cardiac adverse events (sinus tachycardia and premature ventricular contractions (PVCs)) were also significantly less frequent in groups II and III compared to group I.

Conclusions

Adding MgSO₄, either through IV or subcutaneous routes, is associated with lower intraoperative HR, MAP, and postoperative pain scores and a remarkable decrease in epinephrine-induced cardiac adverse events during liposuction.

Effect of Perioperative Intravenous Magnesium Sulfate on Postoperative Pain After Iliac Venous Stenting

BACKGROUND

The aim of the present study was to evaluate the effect of perioperative intravenous (IV) magnesium sulfate (MS) on low back pain (LBP) severity after iliac venous stent implantation.

METHODS

The present study was a single-center retrospective study. A total of 97 patients who had undergone iliac venous stenting for post-thrombotic syndrome between January 1, 2019 and January 11, 2021 were considered for inclusion in the present study. The patients were divided into two groups: those who had received perioperative MS infusions (group M) and those who had not (control group; group C). Group M was given an IV bolus of 20 mg/kg before anesthesia induction and an IV MS infusion of 20 mg/kg/h during the procedure. Postoperative LBP severity was evaluated using the numerical rating scale at 1, 6, 12, and 24 hours after the procedure. The total tramadol consumption within 24 hours was measured with the help of a patient-controlled analgesia device. Moreover, additional analgesic needs and complaints of nausea and vomiting were evaluated.

RESULTS

A total of 97 patients were considered for inclusion in the present study. Of the 97 patients, 29 were excluded because of a lack of follow-up data, leaving 68 patients for the final analysis (group M, n = 36; group C, n = 32). The demographic data, body mass index, sedation time, procedure time, and stented side data were similar between the two groups (P > .05). The rates of atropine and ephedrine use during the procedure were similar between the two groups (P > .05). The numerical rating scale scores were significantly lower for group M at all follow-up periods (P < .001). The total tramadol consumption at 24 hours postoperatively was 191.94 ± 68.194 mg for group M and 378.75 ± 31.367 mg for group C (P < .001). Additional analgesics were used by 8 patients (22.2%) in group M and 17 patients (53.1%) in group C. Additional analgesic needs were significantly lower for group M (P = .008). Nausea and vomiting were observed in six (19.4%) and four (11.1%) patients in group M and eight (32%) and five (15.6%) patients in group C, respectively (P > .05).

CONCLUSIONS

For patients undergoing iliac venous stenting, perioperative MS infusion was an effective and safe treatment option that reduced LBP severity, opioid consumption, and the need for additional analgesics in the acute postoperative period.

Clinical efficacy of magnesium sulfate injection in the treatment of masseter muscle trigger points: a randomized clinical study

Objective

Myofascial pain syndrome with trigger points is the most common cause of nonodontogenic pain. Although injection of the trigger points is the most effective pain reduction treatment, many patients exhibit recurrence after a short period. Therefore, the aim of the current study was to evaluate the clinical efficacy of magnesium sulfate injections in the treatment of the masseter muscle trigger points when compared to saline injections.

Material and method

This study randomly (1:1) assigned 180 patients to one of two treatment groups based on whether their trigger points were injected with 2 ml of saline or magnesium sulfate. Pain scores, maximum mouth opening (MMO), and quality of life were measured at the pre-injection and 1, 3, and 6 months post-injection.

Results

The pain scores were significantly higher in the saline group during all follow-up assessments, whereas the MMO was significantly higher in the magnesium sulfate group up to 3 months of follow-up (p < 0.001). However, the difference in MMO ceased to be statistically significant after 6 months of follow-up (p = 0.121). Additionally, the patient’s quality of life score was significantly higher in the magnesium sulfate group compared to the saline group (p < 0.001).

Conclusion

Injection of magnesium sulfate is an effective treatment measure for myofascial trigger points. However, further studies with a proper design addressing the limitations of the current study are necessary.

ClinicalTrials: org (ID: NCT04742140) 5/2/2021.

Multimodal Analgesia

Perioperative pain management is one of the domains in which Anesthesiologists are intricately involved, and which is immensely important. Adequate postoperative analgesia is central to avoid both the acute as well as chronic complications of uncontrolled postoperative pain. Preventive analgesia has been identified as an approach to mitigate the phenomenon of central sensitization, which plays an important role in the development of chronic pain after surgery. As an over-reliance on opioids for peri- and postoperative pain control is associated with opioid dependence and hyperalgesia, multimodal analgesia has taken center stage. Multimodal analgesia, in theory, will optimize perioperative pain control, reduce the chance of central sensitization, and avoid the detrimental effects of opioid overuse. Multiple classes of systemic analgesic medications have been used to accomplish these tasks, and the aim of this article is to outline these medications, their mechanisms of action, as well as the evidence behind their individual roles in multimodal analgesia. Regional anesthesia has also been embraced as a key component of multimodal analgesia in orthopedic surgery; however, over the past several years, local infiltration analgesia (LIA) emerged as a viable alternative, particularly in total knee arthroplasty.

Compatibility and stability of an admixture of multiple anaesthetic drugs for opioid-free anaesthesia

The ability to combine and use drugs in a single infusion device may be useful in resource-limited settings. This study examined the chemical stability of an opioid-sparing mixture of ketamine, lidocaine and magnesium sulphate when combined in a single syringe. High-performance liquid chromatography and atomic absorption spectrophotometry were performed on six syringes containing the three-drug mixture. Since most opioid-sparing techniques typically rely on a 24-hour infusion regime, we tested stability at the initial admixing and 24 hours later. Stability was defined as a measured drug concentration within 10% of expected, with the absence of precipitation or pH alterations. Pharmacokinetic simulations were conducted to further show that the achieved plasma drug concentrations were well within an effective analgesic range. All mixed drug concentration measurements were within the required 10% reference limit. No obvious precipitation or interaction occurred, and pH remained stable. Drug stability was maintained for 24 hours. Pharmacokinetic simulations showed that ketamine and lidocaine were within their minimum analgesic effect concentrations. Our results show that this three-drug mixture is chemically stable for up to 24 hours after mixing, with a pharmacokinetic simulation illustrating safe, clinically useful predicted plasma concentrations when using the described admixture.

Implementation of a standardized multimodal pain regimen significantly reduces postoperative inpatient opioid utilization in patients undergoing bariatric surgery

BACKGROUND

Routine opioid use in surgical patients has received attention given the opioid epidemic and a renewed focus on the dangers and drawbacks of opioids in the postoperative setting. Little is known about opioid use in bariatric surgery, especially in the inpatient setting. We hypothesize that a standardized opioid-sparing protocol reduces postoperative inpatient opioid use in bariatric surgery patients.

METHODS

A retrospective cohort study was conducted of bariatric surgery patients at a single institution. From March to September 2019, a standardized intraoperative and postoperative opioid-sparing protocol was designed and implemented along with an educational program for patients regarding safe pain management. Inpatient opioid utilization in patients undergoing surgery in the preintervention phase between April and March 2019 was compared to patients from a postintervention phase of October 2019 to December 2020. Opioid utilization was measured in morphine milliequivalents (MME).

RESULTS

A total of 359 patients were included; 192 preintervention and 167 postintervention. Patients were similar demographically. For all patients, mean age was 44.1 years, mean BMI 49.2 kg/m2, and 80% were female. Laparoscopic sleeve gastrectomy was performed in 48%, laparoscopic gastric bypass in 34%, robotic sleeve gastrectomy in 17%, and robotic gastric bypass in 1%. In the postintervention phase inpatient opioid utilization was significantly lower [median 134.8 [79.0-240.8] MME preintervention vs. 61.5 [35.5-150.0] MME postintervention (p < 0.001)]. MME prescribed at discharge decreased from a median of 300 MME preintervention to 75 MME postintervention (p < 0.001). In the postintervention phase, 16% of patients did not receive an opioid prescription at discharge compared to 0% preintervention (p < 0.001). When examining by procedure, statistically significant reductions in opioid utilization were seen for each operation.

CONCLUSION

Implementation of a standardized intraoperative and postoperative multimodal pain regimen and educational program significantly reduces inpatient opioid utilization in patients undergoing bariatric surgery.

Effect of intravenous magnesium on postoperative pain control for major abdominal surgery: a randomized double-blinded study

Background

This study aimed to evaluate the postoperative analgesic effect of magnesium sulfate during abdominal surgery.

Methods

This randomized double-blinded study involved 84 patients candidates for abdominal surgery into two same groups. In the magnesium group, at first 25 mg/kg/1 h magnesium sulfate; and then, 100 mg/kg/24 h was infused in the intensive care unit. The pain intensity (the primary outcome), was assessed using the numeric rating scale (NRS) every 3 h. If the NRS was > 3, morphine (as a secondary outcome) was used and evaluated. The results were analyzed using SPSS ver. 19 software, and statistical significance was set at P < 0.05

Results

Demographic parameters were similar between the groups. The pain intensity were similar at first and then at the third hour in both groups (P = 0.393 and P = 0.172, respectively), but thereafter between 6 and 24 h, the pain severity was significantly lower in the magnesium group (4.4 ± 1.3 in the control and 3.34 ± 1 in the magnesium group at 6th hour and P = 0.001). In addition, morphine intake in the first 24 h in the two groups had a significant difference, with 13.2 ± 5.7 mg in control group and 8 ± 3.5 mg in magnesium group (P = 0.001).

Conclusions

In this study, intravenous magnesium sulfate after abdominal surgeries for 24 h resolved the pain intensity after six hours and reduced morphine dosage.

Magnesium sulfate administration in difficult laryngoscopy: An effective and safe method

PURPOSE

Difficult laryngeal exposure during laryngeal microsurgery and laser surgery is a major concern for otolaryngologists. This study evaluated the efficacy and safety of magnesium sulfate administration in difficult laryngeal exposure patients.

STUDY DESIGN

Quasi-experimental design.

MATERIALS AND METHODS

Forty adult patients scheduled for laryngeal microsurgery with difficult laryngeal exposure according to Cormack-Lehane (CL) classification were included. Magnesium sulfate 50% (20-30 mg/kg) was administered as a bolus injection. Laryngeal exposure and hemodynamic stability were evaluated before and after the intervention.

RESULTS

CL grading was shown a statistically significant improvement after magnesium sulfate administration. There are no clinically significant changes in the mean arterial pressure, heart rate, and oxygen saturation levels in the patients who received magnesium sulfate for better laryngeal exposure.

CONCLUSION

Magnesium sulfate is an effective and safe drug for better viewing in difficult laryngeal exposure patients.

Magnesium Sulfate and Cerebral Oxygen Saturation in Mild Traumatic Brain Injury: A Randomized, Double-Blind, Controlled Trial

Perioperative cerebral hypoperfusion/ischemia is considered to play a pivotal role in the development of secondary traumatic brain injury (TBI). This prospective randomized, double-blind, controlled study investigated whether magnesium sulfate (MgSO4) infusion was associated with neuroprotection in maintaining regional cerebral oxygen saturation (rSO2) values in patients with mild TBI undergoing general anesthesia. Immediately after intubation, we randomly assigned patients with TBI to receive either intravenous MgSO4 (30 mg/kg for 10 min, followed by a continuous infusion of 15 mg/kg/h) or a placebo (saline) during surgery. We also implemented an intervention protocol for a sudden desaturation exceeding 20% of the initial baseline rSO2. The intraoperative rSO2 values were similar with respect to the median (left. 67% vs. 66%, respectively; p = 0.654), lowest, and highest rSO2 in both groups. The incidence (left 31.2% vs. 24.3%; p = 0.521) and duration (left 2.6% vs. 3.5%; p = 0.638) of cerebral desaturations (the relative decline in rSO2 < 80% of the baseline value) were also similar for both groups. Although the patients suffered serious traumatic injuries, all critical desaturation events were restored (100%) following stringent adherence to the intervention protocol. Intraoperative remifentanil consumption, postoperative pain intensity, and fentanyl consumption at 6 h were lower in the MgSO4 group (p = 0.024, 0.017, and 0.041, respectively) compared to the control group, whereas the satisfaction score was higher in the MgSO4 group (p = 0.007). The rSO2 did not respond to intraoperative MgSO4 in mild TBI. Nevertheless, MgSO4 helped the postoperative pain intensity, reduce the amount of intraoperative and postoperative analgesics administered, and heighten the satisfaction score.

Regional anesthesia and acute perioperative pain management in thoracic surgery: a narrative review

Background and Objective

Thoracic surgery causes significant pain which can negatively affect pulmonary function and increase risk of postoperative complications. Effective analgesia is important to reduce splinting and atelectasis. Systemic opioids and thoracic epidural analgesia (TEA) have been used for decades and are effective at treating acute post-thoracotomy pain, although both have risks and adverse effects. The advancement of thoracoscopic surgery, a focus on multimodal and opioid-sparing analgesics, and the development of ultrasound-guided regional anesthesia techniques have greatly expanded the options for acute pain management after thoracic surgery. Despite the expansion of surgical techniques and analgesic approaches, there is no clear optimal approach to pain management. This review aims to summarize the body of literature regarding systemic and regional anesthetic techniques for thoracic surgery in both thoracotomy and minimally invasive approaches, with a goal of providing a foundation for providers to make individualized decisions for patients depending on surgical approach and patient factors, and to discuss avenues for future research.

Methods

We searched PubMed and Google Scholar databases from inception to May 2021 using the terms “thoracic surgery”, “thoracic surgery AND pain management”, “thoracic surgery AND analgesia”, “thoracic surgery AND regional anesthesia”, “thoracic surgery AND epidural”. We considered articles written in English and available to the reader.

Key Content and Findings

There is a wide variety of strategies for treating acute pain after thoracic surgery, including multimodal opioid and non-opioid systemic analgesics, regional anesthesia including TEA and paravertebral blocks (PVB), and a recent expansion in the use of novel fascial plane blocks especially for thoracoscopy. The body of literature on the effectiveness of different approaches for thoracotomy and thoracoscopy is a rapidly expanding field and area of active debate.

Conclusions

The optimal analgesic approach for thoracic surgery may depend on patient factors, surgical factors, and institutional factors. Although TEA may provide optimal analgesia after thoracotomy, PVB and emerging fascial plane blocks may offer effective alternatives. A tailored approach using multimodal systemic therapies and regional anesthesia is important, and future studies comparing techniques are necessary to further investigate the optimal approach to improve patient outcomes.

Evaluation of the Effects of Oral Magnesium Sachet on the Prevention of Spinal Anesthesia-Induced Headache After Cesarean Section: A Randomized Clinical Trial

Background: Post-dural puncture headache (PDPH) is a common complication of spinal anesthesia. It often goes away after a few days but may be more severe in some patients and persists for weeks. Objectives: This study aimed to evaluate the effect of oral magnesium on the prevention of PDPH after cesarean section for the first time. Methods: In this double-blind, randomized clinical trial, 100 candidates for elective cesarean section under spinal anesthesia were randomly divided into 2 groups: (i) the intervention group that received 300 mg of oral magnesium powder and (ii) the control group that received starch powder. The frequency and severity of headache and amount of analgesic consumption in both groups were measured 1, 2, and 3 days after cesarean section. Data were analyzed using SPSS version 22 at 95% CI. Results: The frequency of PDPH 1, 2, and 3 days after surgery was 8% vs 24% (P = 0.029), 10% vs 26% (P = 0.039), and 12% vs 18% (P = 0.401) in the intervention and control groups, respectively. The mean and SD of pain severity was 0.52 ± 1.83 vs 1.5 ± 2.84 (P = 0.03) on the first day, 0.70 ± 2.19 vs 1.58 ± 2.86 (P = 0.05) on the second day, and 0.82 ± 2.32 vs 1.18 ± 2.62 on the third day (P = 0.43) in the intervention and control groups, respectively. Although more patients in the control group received rescue analgesia, no significant difference was seen between the 2 study groups. Conclusions: In women candidates for cesarean section, oral administration of 300 mg magnesium 2 hours before surgery significantly reduces the frequency and severity of PDPH, but its impact on reducing analgesic consumption is not significant.

Nonopioid Analgesics for the Perioperative Geriatric Patient: A Narrative Review

Management of acute perioperative pain in the geriatric patient can be challenging as the physiologic and pharmacokinetic changes associated with aging may predispose older patients to opioid-related side effects. Furthermore, elderly adults are more susceptible to postoperative delirium and postoperative cognitive dysfunction, which may be exacerbated by both poorly controlled postoperative pain and commonly used pain medications. This narrative review summarizes the literature published in the past 10 years for several nonopioid analgesics commonly prescribed to the geriatric patient in the perioperative period. Nonopioid analgesics are broken down as follows: medications prescribed throughout the perioperative period (acetaminophen and nonsteroidal anti-inflammatory drugs), medications limited to the acute perioperative setting (N-methyl-D-aspartate receptor antagonists, dexmedetomidine, dexamethasone, and local anesthetics), and medications to be used with caution in the geriatric patient population (gabapentinoids and muscle relaxants). Our search identified 1757 citations, but only 33 specifically focused on geriatric analgesia. Of these, only 21 were randomized clinical trials' and 1 was a systematic review. While guidance in tailoring pain regimens that focus on the use of nonopioid medications in the geriatric patient is lacking, we summarize the current literature and highlight that some nonopioid medications may extend benefits to the geriatric patient beyond analgesia.

The effect of magnesium sulfate on emergence agitation in children undergoing general anesthesia: A systematic review and meta-analysis

STUDY OBJECTIVE

Emergence agitation (EA) is a common complication in pediatric patients after general anesthesia. The effectiveness of magnesium sulfate in decreasing the incidence of EA in children remains controversial. Therefore, a systematic review and meta-analysis was performed to assess the efficacy of magnesium sulfate in preventing EA in pediatric patients following general anesthesia.

DESIGN

Systematic review and meta-analysis.

SETTING

PubMed, Embase, Web of Science, and Cochrane Library were searched to identify eligible randomized controlled trials from their respective database inception dates to June 30, 2021.

PATIENTS

Pediatric patients (< 18 years old) undergoing general anesthesia.

INTERVENTIONS

Intravenous administration of magnesium sulfate.

MEASUREMENTS

The primary outcome of the meta-analysis was EA incidence. The risk of bias of the included studies was evaluated using the revised Cochrane risk of bias tool for randomized trials (RoB 2.0). Grading of Recommendations, Assessment, Development, and Evaluation was applied to assess the level of certainty.

MAIN RESULTS

Eight studies with 635 participants were identified. The forest plot revealed no significant difference in the incidence of EA between patients treated with magnesium sulfate and the control group (risk ratio = 0.69, 95% confidence interval [0.44, 1.07]; P = 0.10, I² = 74%, moderate level of certainty). Additionally, magnesium sulfate did not reduce postoperative pediatric anesthesia emergence delirium scores but prolonged the emergence time. No significant differences were observed in postoperative complications (nausea, vomiting, laryngospasm, breath-holding, coughing, oxygen desaturation, and cardiac arrhythmias).

CONCLUSIONS

Administration of magnesium sulfate during general anesthesia did not affect the occurrence of EA in pediatric patients. However, magnesium sulfate can prolong the emergence time without adverse effects. PROSPERO registration number: CRD42021252924.

Interactions between Ketamine and Magnesium for the Treatment of Pain: Current State of the Art

BACKGROUND

Over the past three decades, NMDA-receptor antagonists have been shown to be efficient drugs for treating pain, particularly pain resistant to conventional analgesics. Emphasis will be on the old-new drugs, ketamine and magnesium, and their combination as a novel approach for treating chronic pain.

METHODS

The MEDLINE database was searched via PubMed for articles that were published up to March 1, 2020, with the keywords 'ketamine', 'magnesium', and 'pain' (in the title/abstract).

RESULTS

Studies in animals, as well as humans, have shown that interactions of ketamine and magnesium can be additive, antagonistic, and synergistic. These discrepancies might be due to differences in magnesium and ketamine dosage, administration times, and the chronological order of drug administration. Different kinds of pain can also be the source of divergent results.

CONCLUSION

This review explains why studies performed with a combination of ketamine and magnesium have given inconsistent results. Because of the lack of efficacy of drugs available for pain, ketamine and magnesium in combination provide a novel therapeutic approach that needs to be standardized with a suitable dosing regimen, including the chronological order of drug administration.

Impact of intraoperative intravenous magnesium on spine surgery: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The effectiveness and safety of intraoperative intravenous magnesium (IIM) on spine surgery remain uncertain, as recent randomized controlled trials (RCTs) yielded conflicting results. The purpose of this study was to determine the impact of IIM on spine surgery.

METHODS

A literature search was performed on multiple electronic databases, ClinicalTrial.gov and Google Scholar on July 12th 2021, and reference lists were examined. We selected RCTs comparing the effects of IIM with placebo treatment on spine surgery. We calculated pooled standard mean difference (SMD) or risk ratio (RR) with 95% confident interval (CI) under a random-effect model. We assessed risk of bias using Cochrane risk-of-bias tool and Jadad score was applied to assess the quality of each included trial. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to determine the confidence in effect estimates. Sensitivity analysis was conducted by omitting each included study one by one from the pooled analysis. PROSPERO Registration: CRD42021266170.

FINDINGS

Fourteen trials of 781 participants were included. Low- to moderate-quality evidence suggested that IIM reduces postoperative morphine consumption at 24 h (SMD: -1·61 mg, 95% CI: -2·63 to -0·58) and intraoperative remifentanil requirement (SMD: -2·09 ug/h, 95% CI: -3·38 to -0·81). High-quality evidence suggested that IIM reduces the risk of postoperative nausea and vomiting compared with placebo (RR: 0·43, 95% CI: 0·26 to 0·71). Besides, moderate-quality evidence suggested that recovery orientation time in the IIM group is longer than control group (SMD: 1·13 min, 95% CI: 0·83 to 1·43).

INTERPRETATION

IIM as adjuvant analgesics showed overall benefits on spine surgery in terms of reducing analgesic requirement and postoperative nausea and vomiting; however, potential risks of IIM, such as delayed anesthetic awakening, should not be ignored. Future evidence will inform the optimal strategy of IIM administration for patients undergoing spine surgery.

FUNDING

This study was funded by Beijing Municipal Natural Science Foundation (Grant No :7212117).

Opioid sparing strategies for perioperative pain management other than regional anaesthesia: A narrative review

Opioids play a crucial role in pain management in spite of causing increased hospital morbidity and related costs. It may also cause significant risks such as postoperative nausea and vomiting (PONV), sedation, sleep disturbances, urinary retention and respiratory depression (commonly referred to as opioid related adverse effects) in postoperative patients. In order to evade these opioid related side effects and also improve pain management, multimodal analgesia i.e., combination of different analgesics, was introduced more than a decade ago. Both pharmacological and non-pharmacological techniques are available as opioid sparing analgesia. Research from around the world have proved pharmacological techniques ranging from acetaminophen, NSAIDs (non-steroidal anti-inflammatory drugs), N-methyl-D-aspartate receptor antagonists (NDMA), alpha-2 agonists, anticonvulsants such as gamma aminobutyric acid analogues, beta-blockers, capsaicin, lignocaine infusion to glucocorticoids to be effective. On the other hand, non-pharmacological methods include techniques such as cognitive behavioral therapy, transcutaneous electrical nerve stimulation (TENS), electroanalgesia, acupuncture and hypnosis. However, research regarding the effect of these non-pharmacological techniques on pain management is still needed.

Perioperative Magnesium for Postoperative Analgesia: An Umbrella Review of Systematic Reviews and Updated Meta-Analysis of Randomized Controlled Trials

The purpose of this study was to summarize and evaluate evidence on the effectiveness of perioperative magnesium as an adjuvant for postoperative analgesia. We conducted an umbrella review of the evidence across systematic reviews and meta-analyses of randomized controlled trials (RCTs) on the effect of perioperative magnesium on pain after surgical procedures. Two independent investigators retrieved pain-related outcomes and assessed the methodological quality of the evidence of included studies using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR) tool, and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. In addition, an updated meta-analysis of postoperative pain-related outcomes with a trial sequential analysis (TSA) was conducted. Of the 773 articles initially identified, 17 systematic reviews and meta-analyses of 258 RCTs were included in the current umbrella review. Based on the AMSTAR tool, the overall confidence of the included systematic reviews was deemed critically low to low. Pain score, analgesic consumption, time to first analgesic request, and incidence of analgesic request were examined as pain-related outcomes. According to the GRADE system, the overall quality of evidence ranged from very low to moderate. While the updated meta-analysis showed the beneficial effect of perioperative magnesium on postoperative analgesia, and TSA appeared to suggest sufficient existing evidence, the heterogeneity was substantial for every outcome. Although the majority of included systematic reviews and updated meta-analysis showed a significant improvement in outcomes related to pain after surgery when magnesium was administered during the perioperative period, the evidence reveals a limited confidence in the beneficial effect of perioperative magnesium on postoperative pain.

Magnesium Sulfate Enables Patient Immobilization during Moderate Block and Ameliorates the Pain and Analgesic Requirements in Spine Surgery, Which Can Not Be Achieved with Opioid-Only Protocol: A Randomized Double-Blind Placebo-Controlled Study

Spine surgery is painful despite the balanced techniques including intraoperative and postoperative opioids use. We investigated the effect of intraoperative magnesium sulfate (MgSO₄) on acute pain intensity, analgesic consumption and intraoperative neurophysiological monitoring (IOM) during spine surgery. Seventy-two patients were randomly allocated to two groups: the Mg group or the control group. The pain intensity was significantly alleviated in the Mg group at 24 h (3.2 ± 1.7 vs. 4.4 ± 1.8, p = 0.009) and 48 h (3.0 ± 1.2 vs. 3.8 ± 1.6, p = 0.018) after surgery compared to the control group. Total opioid consumption was reduced by 30% in the Mg group during the same period (p = 0.024 and 0.038, respectively). Patients in the Mg group required less additional doses of rocuronium (0 vs. 6 doses, p = 0.025). Adequate IOM recordings were successfully obtained for all patients, and abnormal IOM results denoting warning criteria (amplitude decrement >50%) were similar. Total intravenous anesthesia with MgSO₄ combined with opioid-based conventional pain control enables intraoperative patient immobilization without the need for additional neuromuscular blocking drugs and reduces pain intensity and analgesic requirements for 48 h after spine surgery, which is not achieved with only opioid-based protocol.