Magnesium Can Decrease Postoperative Physiological Ileus and Postoperative Pain in Major non Laparoscopic Gastrointestinal Surgeries: A Randomized Controlled Trial

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.

Magnesium Sulfate Treatment During Total Knee Arthroplasty Decreases Postoperative Urinary Retention: A Retrospective Propensity Score-Matched Analysis

Postoperative urinary retention (POUR) is a common complication after total knee arthroplasty. Currently, there are no clinical data regarding the effects of magnesium sulfate on POUR. Here, we investigated the effects of intraoperative magnesium sulfate infusion in patients with POUR following total knee arthroplasty. We reviewed the medical records of patients who underwent elective unilateral total knee arthroplasty under spinal anesthesia between June 2016 and May 2018. The patients were grouped based on whether they were treated with magnesium (magnesium group) or not (control group). We investigated the incidence of POUR and the postoperative analgesic requirement. Totally, 483 patients were included in the analysis. After propensity score matching with the control group, the magnesium group showed a lower incidence of POUR (odds ratio, 0.49; 95% CI, 0.29–0.83; p = 0.011) and lesser opioid consumption (p = 0.049) than the control group. Multivariate logistic regression analysis revealed that intraoperative continuous infusion of magnesium (p = 0.008) and age (p = 0.001) were significantly related to the incidence of POUR. This retrospective observational study demonstrated that administration of magnesium sulfate was associated with a lower incidence of POUR following total knee arthroplasty.

Pain Management in Enhanced Recovery after Surgery (ERAS) Protocols

Pain control is an integral part of Enhanced Recovery after Surgery (ERAS) protocols for colorectal surgery. While opioid therapy remains the mainstay of therapy for postsurgical pain, opioids have undesired side effects including delayed recovery of bowel function, respiratory depression, and postoperative nausea and vomiting. A variety of nonopioid systemic medical therapies as well as regional and neuraxial techniques have been described as improving pain control while reducing opioid use. Multimodal and preemptive analgesia as part of an ERAS protocol facilitates early mobility and early return of bowel function and decreases postoperative morbidity. In this review, we examine several multimodal therapies and their impact on postoperative analgesia, opioid use, and recovery for patients undergoing colorectal surgery.

The Comparison of Preventive Analgesic Effects of Ketamine, Paracetamol and Magnesium Sulfate on Postoperative Pain Control in Patients Undergoing Lower Limb Surgery: A Randomized Clinical Trial

Background

In considering the importance of postoperative pain management and its consequences on its related secondary outcomes including nausea, vomiting, and operation-related complications, we aimed to compare the effectiveness of the three analgesic agents including ketamine, paracetamol, and magnesium sulfate for postoperative pain relief and associated consequences in this trial.

Materials and Methods

In this double-blinded randomized control clinical trial, patients scheduled for elective lower extremity orthopedic surgery under general anesthesia were enrolled and randomized into four groups for receiving intravenous ketamine (0.25 mg/kg), paracetamol (15 mg/kg), magnesium sulfate (7.5 mg/kg), and placebo (normal saline), immediately after the induction of anesthesia. Postoperative pain scores, analgesic, and metoclopramide use, and frequency of vomiting and satisfaction score of studied patients in the four studied groups during the 6 h, 6-12 h, and 12-24 h after recovery were recorded and compared.

Results

In this trial, thirty patients randomized in each studied groups. Mean of postoperative pain score was significantly lower in ketamine group than others during 24 h after recovery (P < 0.001). Mean of additive analgesic use was significantly lower in ketamine group during 12 h after recovery (P < 0.001), but it was not significantly different during 12-24 h after recovery (P = 0.12). Mean of vomiting frequency and metoclopramide use was not different between groups (P > 0.05). Excellent and good satisfaction score were significantly higher in ketamine group than other groups (P = 0.04).

Conclusions

Ketamine has more superior effect for during recovery and postoperative pain controlling and analgesic use than paracetamol and magnesium sulfate.

The impact of magnesium sulfate as adjuvant to intrathecal bupivacaine on intra-operative surgeon satisfaction and postoperative analgesia during laparoscopic gynecological surgery: randomized clinical study

Background

Surgeon satisfaction and patient analgesia during the procedure of laparoscopic surgery are important issues. The aim of this work was to study if an intrathecal (IT) Bupivacaine combined with Magnesium sulfate may or may not provide good surgeon satisfaction in addition to improvement of intraoperative and postoperative analgesia.

Methods

Sixty female patients were enrolled in this prospective, randomized, double-blind controlled clinical trial study. All patients were operated for gynecological laparoscopic surgery under spinal anesthesia. Patients were divided into two groups (Bupivacaine and Magnesium). Group Bupivacaine (30 patients) received intrathecal Bupivacaine 0.5% only (15 mg), while 30 patients in group Magnesium received intrathecal Bupivacaine (15 mg) in addition to intrathecal Magnesium sulfate (50 mg). The sensory block level, the intensity of motor block, the surgeon satisfaction, the intraoperative visual analog scale (VAS) for pain assessment, the postoperative VAS, and side effects were recorded during the intraoperative period and within the first 24 hours after surgery in the post-anesthesia care unit.

Results

Surgeon satisfaction, intraoperative shoulder pain, postoperative pain after 2 h, and perioperative analgesic consumption (ketorolac) were significant better in group Magnesium than in group Bupivacaine. (P < 0.05). The onset of motor and sensory blocks was significant longer in group Magnesium than the other one. The incidence of PONV, pruritus and urinary retention was insignificant statistically between both groups.

Conclusions

Magnesium sulfate if used intrathecally as an adjuvant to Bupivacaine would provide a better surgeon satisfaction and would improve the analgesic effect of spinal anesthesia used for gynecological laparoscopic surgery.

Analgesic effect and safety of single-dose intra-articular magnesium after arthroscopic surgery: a systematic review and meta-analysis

To examine the analgesic effect and safety of single-dose intra-articular (IA) magnesium (Mg) after arthroscopic surgery. Pubmed, Embase and Cochrane library were searched through in January 2016. Eight RCTs and eight experimental studies were included. The IA Mg exhibited a significantly lower pain score when compared with placebo (MD, -0.41, 95% CI, -0.78 to -0.05, p = 0.03). There was no significant difference between Mg and bupivacaine in terms of pain relief and the time to first analgesic request. Furthermore, statistically significant differences both in pain score (MD, -0.62, 95% CI, -0.81 to -0.42, p < 0.00001) and time to first analgesic request (MD, 6.25, 95% CI, 5.22 to 7.29, p < 0.00001) were observed between Mg plus bupivacaine and bupivacaine alone. There was no statistically significant difference among the various groups with respect to adverse reactions. Most of the included in vitro studies reported the chondrocyte protective effect of Mg supplementation. There were also two in vivo studies showing the cartilage protective effect of IA Mg. The single-dose IA Mg following arthroscopic surgery was effective in pain relief without increasing adverse reactions, and it could also enhance the analgesic effect of bupivacaine. In addition, Mg seemed to possess the cartilage or chondrocyte protective effect based on experimental studies.

Postoperative ileus: in search of an international consensus on definition, diagnosis, and treatment

PURPOSE

Postoperative ileus (POI) is a frequent complication after abdominal surgery; nonetheless, it remains poorly defined. Our aim was to achieve an international consensus among leading colorectal surgeons on definition, prevention, and treatment of POI.

METHODS

Thirty-five experts from five continents participated in a three-round Delphi process. Round 1 contained open-ended questions on POI and postoperative nausea and vomiting (PONV). Round 2 included closed-ended questions. Round 3 measured agreement on a 5-point Likert scale. Consensus was defined when items were rated as agree or strongly agree by at least 70 % of the experts.

RESULTS

Experts reached following consensus: POI is a temporary inhibition (86 %) of gastrointestinal motility after surgical intervention due to non-mechanical causes (89 %) and prevents sufficient oral intake (96 %). Abdominal distension/tenderness are the most relevant clinical signs (71 %). Nasogastric tube placement is not mandatory (78 %) but can be removed without previous clamping (81 %)/gastrointestinal contrast study (100 %). Preventive measures are recommended to decrease the risk of POI (96 %): narcotic sparing analgesia (89 %) and fluid optimization (74 %). Treatment of POI should include stimulation of ambulation (96 %) and stop of opioids (74 %). Total parenteral nutrition is recommended from the 7th day without sufficient oral intake (81 %). There was no consensus on the ranking of POI's symptoms, on the imaging modality of choice for the diagnosis of POI, neither on the difference between POI and PONV.

CONCLUSIONS

This Delphi study achieved consensus on the definition, relevant clinical signs, prevention, treatment, and supportive care of POI. Areas of non-consensus were identified (necessity and modality of radiologic imaging to establish the diagnosis, difference between POI and PONV), giving opportunity for further research.

Comparison of the Effects of Magnesium Sulfate and Remifentanil on Hemodynamic Responses During Tracheal Extubation After Laparotomy: A Randomized Double-blinded Trial

BACKGROUND

Because blood pressure and heart rate (HR) elevations during tracheal extubation are common, different medications have been studied to prevent such complications.

OBJECTIVES

To compare magnesium sulfate, remifentanil, and placebo regarding mean arterial pressure (MAP) and HR changes during/after tracheal extubation, in patients who underwent laparotomy.

MATERIALS AND METHODS

In this randomized double-blinded trial, 120 patients undergoing laparotomy were evenly divided into three groups, including remifentanil (1 mcg/kg), magnesium sulfate (50 mg/kg), or normal saline, as placebo. Hemodynamic responses (MAP and HR) were documented at different times (before operation, during medication administration, immediately before extubation, immediately after extubation, and also 3, 5, and 10 minutes after extubation). The double burst time (DBT) was determined using neuromuscular monitoring, as time interval, between administration of reverse medication and DBT of 100%.

RESULTS

The HR was significantly lower, immediately after extubation and 3, 5, and 10 minutes after extubation, in both magnesium and remifentanil groups, compared to normal saline (P < 0.001). The MAP was also lower in magnesium and remifentanil groups, immediately after extubation and 3 minutes after extubation, in comparison to the normal saline group (P < 0.001). Mean (± SD) DBT 100% was significantly higher in magnesium group (30.2 ± 15.3) vs. remifenatnil (13.6 ± 6.8) and normal saline (13.5 ± 8.2) groups (P < 0.001).

CONCLUSIONS

Both remifentanil and magnesium had favorable outcomes in preventing HR and MAP elevation after tracheal extubation. However, remifentanil was associated with more rapid regaining of consciousness and reversal of muscular relaxation.

Addition of Intrathecal Magnesium Sulfate to Bupivacaine for Spinal Anesthesia in Cesarean Section

Background:

Spinal anesthesia is widely used for caesarean section. Addition of intrathecal magnesium sulfate to local anesthetics seems to improve the quality of block and prolong the duration of analgesia.

Objectives:

The present study was designed to examine whether addition of intrathecal magnesium sulfate enhances the analgesic efficacy of intrathecal bupivacaine in patients undergoing cesarean section.

Patients and Methods:

We conducted a randomized, prospective, double-blind, case-control, clinical trial. Eighty patients were scheduled for cesarean section under spinal anesthesia. The patients were randomly allocated to receive either 10 mg of hyperbaric bupivacaine 0.5% (control group) or 10 mg of hyperbaric bupivacaine 0.5% plus 50 mg magnesium sulfate (case group) intrathecally. Hemodynamic variability, onset and duration of block and duration of analgesia were evaluated.

Results:

The onset of sensory blockade was delayed in case group compared with control group, and this was statistically significant. The onset of motor blockade had no difference in both groups. The duration of motor blockade was similar. Post-operative analgesia was longer in magnesium sulfate group but the difference was not meaningful. The intraoperative hemodynamic variability showed no significant differences between groups.

Conclusions:

This study showed that the addition of intrathecal magnesium sulfate to bupivacaine is not desirable in patients undergoing cesarean section due to the delay in the onset of sensory blockade and the lack of significant effects of magnesium on post-operative pain.

Evaluation of the anti-inflammatory effects of peri-operative infusion of magnesium sulfate on the microsurgical procedures for intracranial tumors

Background:

The anti-inflammatory properties of magnesium sulfate have never been discussed in brain tumor surgeries.

Objectives:

This study is aimed to find anti-inflammatory aspects of high dose magnesium sulfate infusion during perioperative period of neurosurgical patients through checking the serial C-reactive protein (CRP) blood levels as a biomarker of inflammation.

Patients and Methods:

Sixty patients who were candidate for elective craniotomy were enrolled randomly into two equal groups to receive either magnesium sulfate or normal saline during their perioperative period. Infusion of magnesium was performed three times during the study and a summation of 15 grams was administered: 1- two days before surgery, 2- one day before surgery, 3- from the beginning of surgery (five grams was infused within six hours in each session). Serum level of CRP was checked just before commencement of magnesium infusion and on the first and second day after surgery as primary outcome. Hemodynamic parameters, total propofol requirement and total blood loss were recorded as well.

Results:

No significant difference was found between groups in terms of serum CRP levels. The mean arterial blood pressure, heart rate, blood loss and total anesthetic requirement were significantly lower in magnesium group in comparison to the control group.

Conclusions:

We did not find conclusive evidence for anti-inflammatory effects of magnesium in craniotomy for microsurgery of intracranial tumors using CRP level changes. However, high dose magnesium might be suggested as a safe anesthetic adjuvant in neurosurgery.

The effect of intravenous magnesium sulfate and lidocaine in hemodynamic responses to endotracheal intubation in elective coronary artery bypass grafting: a randomized controlled clinical trial

BACKGROUND

There have been many concerns about alteration in hemodynamic parameters within and shortly after endotracheal intubation (ETI) in patients scheduled for elective coronary artery bypass grafting (CABG).

OBJECTIVES

We compared the attenuation effect of magnesium sulfate and lidocaine on hemodynamic responses after ETI, in patients undergoing CABG.

PATIENTS AND METHODS

In this randomized controlled trial 150 patients undergoing elective CABG were enrolled. Included patients were randomly allocated to three groups and received lidocaine (1.5 mg/kg), magnesium sulfate (50 mg/kg within five minute), or normal saline, 90 seconds before ETI. Baseline hemodynamic parameters including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded immediately before anesthesia induction, before intubation, immediately after intubation, and at second and fifth minutes after intubation.

RESULTS

The baseline hemodynamic variables had no deference among the three groups. HR between intubation and five minute after intubation was significantly lower in two groups received lidocaine or magnesium sulfate in comparison with placebo group. Lidocaine induced more than 20% decrease in HR and MAP immediately after intubation; hence, lidocaine group showed significant MAP reduction in comparison with the two other groups.

CONCLUSIONS

Lidocaine induced hemodynamic instability but premedication of magnesium sulfate maintained hemodynamic stability after intubation. Therefore, in patients undergoing CABG who received high-dose intravenous analgesic for general anesthesia, the administration of magnesium sulfate might result in maintaining hemodynamic stability after ETI in comparison with lidocaine.