Analgesic effect of magnesium sulfate during total intravenous anesthesia: randomized clinical study

Influence of magnesium sulfate on the pharmacodynamic characteristics of rocuronium. A randomized clinical trial

BACKGROUND

As a multimodal anesthesia adjuvant, magnesium sulfate (MgSO4) plays an important role in the anesthetic arsenal, due to its properties and substantial synergistic effects with other drugs such as opioids, hypnotics and neuromuscular blocking drugs (NMBD). Rocuronium is a non-depolarizing NMBD used widely in general anesthesia, and its association with MgSO4 is still a concern. This study aimed to evaluate the influence of MgSO4 at a dose of 30 mg kg-1 on the pharmacodynamic characteristics of rocuronium.

METHODS

It was a double-blinded, randomized controlled trial in adult female patients scheduled for open hysterectomies with total intravenous anesthesia. Patients were allocated randomly to receive MgSO4 (30 mg kg-1) diluted in 100 mL of saline, 10 minutes before induction, or 100 mL of saline. Primary outcome: Influence of MgSO4 on latency (onset time), clinical duration (CD25%) and time to recover 90% of T4/T1 - train of four (TOF = 0.9). In total, 70 patients were enrolled, 35 per group.

RESULTS

The baseline characteristics were similar. A comparative analysis showed a significant difference between the groups regarding latency in seconds (lower with MgSO4) 40.00 (35-45 [30-68]) compared to saline 53.00 (50-60 [40-90]) (P < 0.001), CD25% in minutes (longer with MgSO4) 61.00 (53-70 [30-110]), saline 38.00 (35-48 [30-87 (P <0.001), and TOF = 0.9 in minutes, longer with MgSO4 98.00 (88-111 [53-176]), saline 60.00 (55-78 [44-130]) (P < 0.001). MgSO4 was found to reduce opioid consumption in the postanesthetic care unit.

CONCLUSIONS

The strong impact of MgSO4 on the pharmacodynamics of rocuronium confirms the indispensable role of quantitative neuromuscular blockade monitoring to guide reversal.

F. M, S. D, M. A. M. C. G, F. A, C. B, F. B. S, J. E. V. Optimal Dose of Magnesium Sulfate Infusion in Obese Patients: A Double-Blind Randomized Trial

Background: Magnesium sulfate reduces opioid use and its associated side effects. However, no consensus exists on whether the optimal dosing should be based on actual body weight or adjusted ideal body weight. The primary objective of this study was to compare postoperative analgesia after magnesium sulfate infusion, using doses calculated based on actual body weight versus adjusted ideal body weight. Methods: This prospective, randomized, double-blind, controlled clinical trial included 75 participants who underwent target-controlled intravenous general anesthesia. The participants were divided into three groups: a control group (CG), a group receiving magnesium sulfate calculated by actual body weight (AWG), and a group receiving magnesium sulfate calculated based on the adjusted ideal body weight (IWG). Results: The AWG had significantly lower pain scores than the CG (p < 0.001) and IWG (p=0.017). Opioid use was similar between the AWG and IWG, but significantly higher in the CG (AWG = IWG, p=0.08; CG > AWG, p < 0.001; CG = IWG, p 0.03). The increase in magnesium concentration did not reach clinically relevant levels. Neuromuscular blockade latency decreased in the groups receiving magnesium sulfate (p < 0.001 in both comparisons) compared to the CG. Conclusion: Calculating the dose of magnesium sulfate based on actual body weight enhances postoperative analgesia. The increase in magnesium concentration was not clinically significant and did not interfere with the action of cisatracurium in the groups receiving magnesium sulfate. Trial Registration: ClinicalTrials.gov identifier: NCT04645719.

Innovations in Pain Management for Abdominoplasty Patients: A Systematic Review

Background/Objectives: Abdominoplasties are prevalent surgical procedures for improving lower abdominal contours, necessitating effective pain management. Insufficient management can increase opioid usage, dependency risks, and adverse effects. This review investigates various strategies in abdominoplasty pain management, aiming to reduce opioid dependence and improve patient care. Methods: A comprehensive systematic literature search (MEDLINE, Cochrane, PubMed, Web of Science, EMBASE) was conducted, spanning from their inception to January 2024, using keywords such as 'abdominoplasty' and 'postoperative pain management'. Included studies focused on nonopioid interventions in adults, encompassing various study designs. Non-English publications and those not meeting outcome criteria were excluded. Bias in studies was assessed using specific tools for randomized and non-randomized trials. Results: Thirty-five studies, published between 2005 and 2024, were included, involving 3636 patients with an average age of 41.8. Key findings highlighted the effectiveness of transversus abdominis plane blocks in reducing opioid use and pain. Pain pump catheters also showed promise in improving pain management and reducing opioid dependency. Local anesthetics demonstrated varying degrees of efficacy, while other alternatives like ketamine and NSAIDs successfully reduced postoperative pain and opioid requirements. The bias assessment of the RCTs revealed "low" and "some concerns" ratings, indicating a need for more detailed methodology reporting and management of missing data. The cohort studies generally attained "moderate" risks of bias, primarily due to confounding variables and outcome data reporting. Conclusions: Nonopioid analgesics show potential in postoperative pain management for abdominoplasties, but further research is needed to confirm their effectiveness and optimize patient care.

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.

A study of hemodynamic effects, postoperative recovery, and safety of esketamine (right handed) during flexible bronchoscopy under general anesthesia

OBJECTIVE

Flexible bronchoscopy during general anesthesia has become an indispensable tool. Anesthetics are widely utilized in flexible bronchoscopy (FB). This study delved into the application value of a subanesthetic dose of esketamine (ES) (right handed) in flexible bronchoscopy during general anesthesia.

METHODS

A sample of 160 patients who underwent flexible bronchoscopy during general anesthesia were selected as study subjects and were equally divided into the control and ES groups, with clinical baseline data (age, sex, body mass index, American Society of Anesthesiologists grading) collected. Hemodynamic parameters (mean artery pressure, heart rate, pulse blood oxygen saturation) at different time points, the onset time of anesthesia, surgery time, analgesia maintenance time, anesthesia awakening time, and perioperative adverse reactions were recorded. Visual analogue scale (VAS), Mini-Mental State Examination (MMSE), and quality of recovery-40 (QoR-40) scales were utilized for assessing post-surgery satisfaction, cognitive function, and post-surgery early recovery quality.

RESULTS

The hemodynamics were stable at each time point, but patients in the ES group were more stable than those in the control group. Patients in the ES group exhibited faster onset and awakening time of anesthesia, longer duration of analgesia, and lower total incidence of adverse reactions versus the control group. The patients' QoR-40 total scores in the ES group were improved versus the control group at 1 day after surgery.

CONCLUSION

Compared with fentanyl, the use of ES (right handed) in flexible bronchoscopy during general anesthesia produces more stable hemodynamics, faster onset and recovery time of anesthesia, longer duration of analgesia, lower incidence of adverse reactions, and improved early postoperative recovery quality in patients.

Effect of Intraoperative infusion Magnesium Sulfate Infusion on Postoperative Quality of Recovery in Patients Undergoing Total Knee Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Trial

Background

Magnesium sulfate, an intravenous adjuvant, has recently attracted immense attention in multimodal analgesia. Previous studies confirmed the crucial role of magnesium sulfate in postoperative pain and nociceptive hypersensitivity. However, the effect of magnesium sulfate in multimodal analgesia on the quality of recovery (QoR) for elderly patients has not been thoroughly studied. Therefore, the present experiment aimed to investigate the effect of continuous intravenous magnesium sulfate on the quality of postoperative recovery in elderly patients undergoing total knee arthroplasty (TKA).

Patients and Methods

In this study, a total of 148 patients scheduled to undergo unilateral total knee arthroplasty were randomized into a magnesium sulfate group (Group M, n=68) and a control group (Group C, n=66) using a double-blind, randomized controlled trial. Before induction of anesthesia, Group M received intravenous magnesium sulfate (40 mg/kg) for 15 min, followed by a continuous infusion (15 mg/kg) until the end of the procedure. In the same manner, Group C received an infusion of the same amount of isotonic saline using the same method as the Group M.

Results

Compared with Group C, Group M had significantly better QoR-15 scores on postoperative day 1(POD1) than Group C (P <0.05). Analysis of the dimensions of QoR-15 scores indicated that Group M exhibited notably reduced levels of pain, and higher levels of emotional state and physical comfort than Group C (P <0.05). Furthermore, Group C had significantly higher numerical rating scale (NRS) scores at POD1 than Group M (P <0.05).

Conclusion

For elderly patients undergoing knee arthroplasty, magnesium sulfate can be used as an adjuvant in a multimodal analgesic regimen to reduce early postoperative pain and improve the quality of early postoperative recovery.

Enhanced recovery after elective spinal surgery: an Australian pilot study

Background

The principles of enhanced recovery after surgery (ERAS) aim to reduce the physiological stress of surgery which in turn improve clinical and health economic outcomes. There is ample evidence in literature supporting ERAS methodologies in other surgical specialties, but its adoption in spinal surgery, especially in Australia remains in infancy. The aim of this project is to describe the early experience with an evidence-based ERAS pathway for simple spine surgery, a first of its kind in Australia.

Methods

An ERAS protocol was designed using an evidenced-based review of the literature. The authors then conducted a prospective cohort analysis looking at outcome of patients undergoing elective spinal (lumbar and cervical) decompression surgery under ERAS principles by a single surgeon on the Westmead Hospital Campus between March 2021 to May 2023. Primary outcomes were patient length of stay (LOS), patient reported pain and disability scores and complications (including readmissions within 30 days and re-operation within 6 months). Secondary outcomes included predictors of failure for same-day discharge.

Results

A total of 52 patients underwent spinal decompression surgeries under the ERAS protocol. Overall 43 out of 52 patients (83.7%) were successfully discharged on the same day as their surgery. Patient reported outcomes were improved at 6 weeks and 6 months confirming durability of intervention. The rates of complications were similar to literature reported rates for simple lumbar or cervical decompression procedures and there were no readmissions within 30 days or re-operations within 6 months of surgery. Being of non-English speaking background [odds ratio (OR) =6.08, P=0.04] and from home alone (OR =10.25, P=0.03) were predictors of failure of same day discharge in this small cohort.

Conclusions

Implementation of ERAS protocols for simple spinal decompression surgeries is feasible and produces durable improved patient outcomes while reducing LOS in hospitals. Patient social factors can be predictive of lack of compliance.

Magnesium Sulfate and Its Versatility in Anesthesia: A Comprehensive Review

In the field of general anesthesia, magnesium sulfate (MgSO4) has become a valuable adjunct because it provides a range of benefits that enhance and optimize conventional aesthetic procedures. This review highlights the various intra-anesthetic benefits of MgSO4 while examining its complex function in the treatment using anesthesia. Magnesium inhibits the release of acetylcholine at the motor endplate and blocks calcium channels at presynaptic nerve terminals. This reduces the amplitude of endplate potential and the excitability of muscle fibers, which increases the potency of a neuromuscular blockade by nondepolarizing neuromuscular blockers. This activity may lessen the need for primary muscle relaxants. Moreover, its capacity to potentially reduce the total amount of main aesthetic agents needed emphasizes its function in maximizing anesthesia dosage, ensuring sufficient depth while perhaps potentially reducing adverse effects linked with increased dosages. MgSO4's adaptable qualities present a viable path for improving anesthetic outcomes, possibly improving patient safety and improving surgical results.

Perioperative analgesia in the elderly

The administration of analgesic drugs in elderly patients should take into account age-related physiological changes, loss of efficiency of homeostatic mechanisms, and pharmacological interactions with chronic therapies. Underestimation of pain in patients with impaired cognition is often linked to difficulties in pain assessment. In the preoperative phase, it is essential to assess the physical status, cognitive reserve, and previous chronic pain conditions to plan effective analgesia. Furthermore, an accurate pharmacological history of the patient must be collected to establish any possible interaction with the whole perioperative analgesic plan. The use of analgesic drugs with different mechanisms of action for pain relief in the intraoperative phase is a crucial step to achieve adequate postoperative pain control in older adults. The combined multimodal and opioid-sparing strategy is strongly recommended to reduce side effects. The use of various adjuvants is also preferable. Moreover, the implementation of non-pharmacological approaches may lead to faster recovery. High-quality postoperative analgesia in older patients can be achieved only with a collaborative interdisciplinary team. The aim of this review is to highlight the perioperative pain management strategies in the elderly with a special focus on intraoperative pharmacological interventions.

The Effect of Remifentanil, MgSO4, or Remifentanil-MgSO4 as Neuroprotectors on BDNF, MAC, and Caspase-3 Levels in Wistar Rats with Traumatic Brain Injury

BACKGROUND: Traumatic brain injury (TBI) can lead to cell death and neurologic dysfunction. Meanwhile, Remifentanyl is an opioid with potent analgesia, while magnesium sulfate (MgSO4) has antinociceptive properties that can prevent hemodynamic instability during laryngoscopy. AIM: This study aims to examine the effect of remifentanil, MgSO4 and their combination on BDNF, MAC, and Caspase-3 levels in Wistar rat models with TBI. METHODOLOGY: An experimental study was conducted on 30 male Wistar rats which were randomly divided into five groups. The control group (G1) received normal saline, the induced group (G2) received normal saline after TBI induction using the modified Feeney method, and the treated group (G3, G4, and G5) received remifentanil, MgSO4, and their combination after TBI induction. The rats’ brain tissues were analyzed for BDNF, MAC, and Caspase-3 levels using ELISA. The data were analyzed statistically with ANOVA followed by post hoc Multiple Comparison Test (p < 0.05). RESULTS: Treatment with remifentanil, MgSO4 or the combination of both in TBI subjects reduced MAC and Caspase-3 but increased the BDNF level. The post hoc multiple comparisons showed significant differences in all groups except groups 3 and 5 in terms of MAC (p = 0.190) and Caspase-3 (p = 0.999). The combination of remifentanil-MgSO4 increased BDNF levels significantly. CONCLUSION: The administration of remifentanil, MgSO4 , or their combination can serve as a neuroprotector in Wistar rat models with TBI by lowering MAC and Caspase-3 as well as increasing BDNF levels.

Intraoperative Analgesia with Magnesium Sulfate versus Remifentanil Guided by Plethysmographic Stress Index in Post-Bariatric Dermolipectomy: A Randomized Study

BACKGROUND

Magnesium sulfate reduces pain scores and analgesic consumption. Its use as an analgesic resource in opioid-free or opioid-sparing techniques have also been tested. The evaluation of the antinociceptive potency of drugs and doses indirectly, through hemodynamic oscillations has been questioned. A relatively new algorithm called the plethysmographic stress index has been considered sensitive and relatively specific as a parameter for assessing the need for intraoperative analgesia.

OBJECTIVES

The aim of this trial was to assess the intraoperative analgesic capacity of magnesium sulfate compared to remifentanil. The secondary objectives were propofol consumption and its latency, the consumption of opioids, ephedrine, and cisatracurium. Patients and Methods. Forty patients scheduled for post-bariatric dermolipectomy were randomly assigned to two groups to receive total intravenous anesthesia with target-controlled hypnosis induced with propofol. Analgesia was obtained in the remifentanil group with remifentanil at an initial dose of 0.2 μg·kg-1·min-1 and in the magnesium sulfate group with magnesium sulfate 40 mg·kg-1 + 10 mg·kg-1·h-1.

RESULTS

There was no statistical hemodynamic difference between the groups before and after orotracheal intubation (p = 0.062) and before and after the surgical incision (p = 0.656). There was also no statistical difference in the variation of mean arterial pressure before and after intubation (p = 0.656) and before and after the surgical incision (p = 0.911). There was similar consumption of cisatracurium, ephedrine, and postoperative opioids between the groups. Some patients in the magnesium sulfate group needed more intraoperative fentanyl and propofol, although the latency of propofol was similar in both the groups.

CONCLUSION

We conclude that using magnesium sulfate in intravenous general anesthesia for post-bariatric dermolipectomy is related to a significant reduction in opioid consumption without compromising hemodynamic stability. Overall, PSI monitoring was helpful in driving the analgesic strategy. The use of magnesium sulfate proved to be an important adjunct in the scenario presented, allowing the use of opioids to be avoided in certain cases. We found no statistical differences in the consumption of neuromuscular blocker and vasoconstrictor. Substituting opioids for magnesium sulfate leads to an increase in propofol consumption in the scenario presented. Studies with a larger sample are needed to corroborate the results presented and evaluate other potential advantages in reducing opioid consumption.

Different modalities of analgesia in open heart surgeries in Mansoura University

Background: Opioid usage in cardiac surgery is considered to be the corner stone in management. Inadequate pain control after cardiac surgery complicates patient recovery and increases the load on healthcare services. Multimodal analgesia can be used to achieve better analgesic effect and improves patient outcome.  Material and methods: A total of 90 patients undergoing cardiac surgery with median sternotomy were randomly allocated equally into three groups intraoperatively where first group received continuous infusion of high dose opioids, second group received boluses of low dose opioids and third group received multimodal non opioid analgesics including dexmedetomidine, ketamine and magnesium sulphate. All patients received the same post-operative analgesic regimen consists of morphine patient controlled analgesia (PCA). Results: Patients in multimodal non opioid group had more stable hemodynamics intra and postoperatively. Also, patients in multimodal group had lower pain scores extubation, earlier extubation, shorter ICU stay, earlier mobilization and earlier return of bowel movements compared to patients of both groups received intraoperative higher opioid doses.