Use Profile of Magnesium Sulfate in Anesthesia in Brazil

Magnesium sulfate for postoperative pain in orthopedic surgery: A narrative review

Magnesium Sulfate (MgSO4) is a widely used adjuvant in anesthesia. Often administered with local anesthetics, it is known to reduce analgesic and opioid consumption while extending the duration of analgesia. MgSO4 applications extend to orthopedic surgeries, cardiovascular and urogenital procedures, offering extended postoperative pain relief. While commonly administered through various routes, there is a research gap concerning the comparative efficacy of intrathecal (IT) and intravenous (IV) MgSO4 administration. This narrative review aims to provide a comparison between IT and IV administration of MgSO4 particularly following orthopedic procedures, where pain management is paramount. A comprehensive literature search was conducted across several electronic databases, trial registries, and gray literature from inception to 2023. Inclusion criteria encompassed studies investigating the effects of perioperative IT administration of magnesium compared to perioperative IV administration of MgSO4 in patients undergoing surgery, with no language restrictions. Our search identified 4326 articles, of which 9 randomized controlled trials met our inclusion criteria. We summarized these selected articles. Four studies discussed IT magnesium sulfate (MgSO4) administration, 2 focused on IT administration in orthopedic surgeries, and 3 explored both IV and IT administration of MgSO4 in orthopedic surgery. IT MgSO4 shows promise in postoperative pain management, delaying block onset and extending duration. Personalized administration choice, considering patient factors and surgery type, is crucial. Further research is needed to refine strategies for better patient outcomes, particularly following orthopedic surgeries.

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.

Effect of opioid-free anesthesia on the incidence of postoperative nausea and vomiting: A meta-analysis of randomized controlled studies

BACKGROUND

Research on opioid-free anesthesia has increased in recent years; however, it has never been determined whether it is more beneficial than opioid anesthesia. This meta-analysis was primarily used to assess the effect of opioid-free anesthesia compared with opioid anesthesia on the incidence of postoperative nausea and vomiting.

METHODS

We searched the electronic databases of PubMed, the Cochrane Library, Web of Science and Embase from 2014 to 2022 to identify relevant articles and extract relevant data. The incidence of postoperative nausea and vomiting, time to extubation, pain score at 24 hours postoperatively, and time to first postoperative rescue analgesia were compared between patients receiving opioid-free anesthesia and those receiving standard opioid anesthesia. Differences in the incidence of postoperative nausea and vomiting were evaluated using risk ratios (95% confidence interval [CI]). The significance of the differences was assessed using mean differences and 95% CI. The heterogeneity of the subject trials was evaluated using the I2 test. Statistical analysis was performed using the RevMan 5.4 software.

RESULTS

Fourteen randomized controlled trials, including 1354 participants, were evaluated in the meta-analysis. As seen in the forest plot, the OFA group had a lower risk of postoperative nausea and vomiting than the control group (risk ratios = 0.41, 95% CI: 0.33-0.51, P < .00001; n = 1354), and the meta-analysis also found that the OFA group had lower postoperative analgesia scores at 24 hours (P < .000001), but time to extubation (P = .14) and first postoperative resuscitation analgesia time (P < .54) were not significantly different.

CONCLUSIONS

Opioid-free anesthesia reduces the incidence of postoperative nausea and vomiting while providing adequate analgesia without interfering with postoperative awakening.

Nebulised fentanyl, dexmedetomidine and magnesium sulphate for attenuation of haemodynamic response to laryngoscopy and tracheal intubation: A double-blinded, randomised comparative study

Background and Aims

Direct laryngoscopy and tracheal intubation cause an increase in heart rate (HR) and blood pressure, called as pressor response. This study aimed to compare nebulised forms of fentanyl, dexmedetomidine and magnesium sulphate to attenuate the haemodynamic response to laryngoscopy and tracheal intubation.

Methods

This double-blinded, randomised study was conducted on 90 patients undergoing elective surgery requiring endotracheal intubation. Nebulisation was done with fentanyl 1 μg/kg (Group A), dexmedetomidine 1 μg/kg (Group B) and magnesium sulphate (MgSO4) (40 mg/kg) (Group C). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and HR were recorded before nebulisation (T0), post-nebulisation (T1) and at 2, 5 and 10 min after intubation (T2, T3, T4). The statistical analysis for comparing continuous variables between the groups was performed using analysis of variance (ANOVA), and a P value <0.05 was considered statistically significant.

Results

Compared to T0, an increase in HR at T2 and T3 was seen in Group A only, which reached baseline values at T4 (P values <0.0001 and 0.037, respectively). No HR value was higher than the baseline readings in groups B and C. The decreasing trend of SBP, DBP and MAP was seen in all three groups. Groups B and C had a statistically significant decrease in all the values from baseline (P values <0.0001).

Conclusion

Nebulised form of dexmedetomidine (1 μg/kg) and magnesium (40 mg/kg) seems to be superior to fentanyl (1 μg/kg) in blunting the stress response to laryngoscopy and tracheal intubation.

Recurarization with magnesium sulfate administered after two minutes sugammadex reversal: A randomized, double-blind, controlled trial

STUDY OBJECTIVE

The current study tested the hypothesis that magnesium sulfate after reversal with sugammadex causes recurarization.

DESIGN

A single-center, prospective, randomized, double-blind, controlled trial.

SETTING

Terciary care hospital in Rio de Janeiro, Brazil.

PATIENTS

Included 60 patients undergoing for elective otolaryngological surgery.

INTERVENTIONS

All patients received total intravenous anesthesia and a single dose of rocuronium (0.6 mg/kg). In 30 patients, the neuromuscular blockade was reversed with sugammadex (4 mg/kg) at the reappearance of one or two posttetanic counts (deep-blockade series). In 30 other patients, sugammadex (2 mg/kg) was administered at the reappearance of the second twitch of the train-of-four (moderate-blockade series). After the normalized train-of-four ratio recovered to ≥0.9, the patients in each series were randomized to receive intravenous magnesium sulfate (60 mg/kg) or placebo for 10 min. Neuromuscular function was measured by acceleromyography.

MEASUREMENTS

The primary outcome was the number of patients who exhibited recurarization (normalized train-of-four ratio < 0.9). The secondary outcome was rescue with an additional dose of sugammadex after 60 min.

MAIN RESULTS

In the deep-blockade series, a normalized train-of-four ratio < 0.9 occurred in 9/14 (64%) patients receiving magnesium sulfate and 1/14 (7%) receiving placebo, RR 9.0 (95% CI: 62-1.30), and (p = 0.002), with four rescues with sugammadex. In the moderate-blockade series, neuromuscular blockade recurred in 11/15 (73%) patients receiving magnesium sulfate and in 0/14 (0%) receiving placebo (p < 0.001), with two rescues. The absolute differences in recurarization were 57% and 73% in the deep-blockade and moderate-blockade, respectively.

CONCLUSIONS

Single-dose magnesium sulfate led to a normalized train-of-four ratio < 0.9, 2 min after recovery from rocuronium-induced deep and moderate neuromuscular blockade using sugammadex. Additional sugammadex reversed prolonged recurarization.

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.

Feasibility and postoperative opioid sparing effect of an opioid-free anaesthesia in adult cardiac surgery: a retrospective study

Background

No previous study investigated the dexmedetomidine-based opioid-free anesthesia (OFA) protocol in cardiac surgery. The main objective of this study was to evaluate the feasibility and the postoperative opioid-sparing effect of dexmedetomidine-based OFA in adult cardiac surgery patients.

Methods

We conducted a single-centre and retrospective study including 80 patients above 18 years old who underwent on-pump cardiac surgery between November 2018 and February 2020. Patients were divided into two groups: OFA (lidocaine, ketamine, dexmedetomidine, MgSO4) or opioid-based anaesthesia (remifentanil and anti-hyperalgesic medications such as ketamine and/or MgSO4 and/or lidocaine at the discretion of the anesthesiologist). The primary endpoint was the total amount of opioid consumed in its equivalent of intravenous morphine during the first 48 postoperative hours. Secondary outcomes included perioperative hemodynamics, post-operative maximal pain at rest and during coughing and adverse outcomes. Data are expressed as median [interquartile range].

Results

Patients in the OFA-group had a higher EuroSCORE II, with more diabetes, more dyslipidemia and more non-elective surgery but fewer smoking history. In the OFA group, the median loading dose of dexmedetomidine was 0.6 [0.4–0.6] μg.kg^− 1 while the median maintenance dose was 0.11 μg.kg^− 1.h^− 1 [0.05–0.20]. In 10 (25%) patients, dexmedetomidine was discontinued for a drop of mean arterial pressure below 55 mmHg. The median total amount of opioid consumed in its equivalent of intravenous morphine during the first 48 postoperative hours was lower in the OFA group (15.0 mg [8.5–23.5] versus 30.0 mg [17.3–44.3], p < 0.001). While no differences were seen with rest pain (2.0 [0.0–3.0] versus 0.5 [0.0–5.0], p = 0.60), the maximal pain score during coughing was lower in OFA group (3.5 [2.0–5.0] versus 5.5 [3.0–7.0], p = 0.04). In OFA group the incidence of atrial fibrillation (18% versus 40%, p = 0.03) and non-invasive ventilation use (25% versus 48%, p = 0.04) were lower. The incidence of bradycardia and the intraoperative use of norepinephrine were similar between both groups.

Conclusion

Dexmedetomidine-based OFA in cardiac surgery patients is feasible and could be associated with a lower postoperative morphine consumption and better postoperative outcomes. Further randomized studies are required to confirm these promising results and determine the optimal associations, dosages, and infusion protocols during cardiac surgery.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01362-1.

Magnesium Citrate Increases Pain Threshold and Reduces TLR4 Concentration in the Brain

Magnesium is being investigated in various clinical conditions and has shown to be effective in some chronic pain models. However, it is not clear if oral magnesium use affects pain perception in acute pain. TLR4's (toll-like receptor) role in pain perception has emerged through its role in immune pathways and ion channels. The aim of this study is to investigate the effect of a single oral dose of magnesium citrate on pain conduction and whether with magnesium, the expression of TLR4 changes in the acute phase. Following a single dose of 66-mg/kg magnesium citrate administration to male Balb-c mice, pain perception (via hot-plate test), motor conduction (via electrophysiological recording, forelimb grip strength, rotarod and open-field tests), and emotional state (via elevated plus maze and forced swim test) were evaluated. In behavioral experiments, the control group was compared with applied magnesium for three different time groups (4, 8, 24 h). TLR4 expression was measured in four groups: control, magnesium (Mg), hot plate (HP), and Mg + HP. Hot plate latency was prolonged in the magnesium group (p < 0.0001) and electrophysiological recordings (p < 0.001) and forelimb grip strength measurement (p < 0.001) determined motor latency. Compared with the untreated hot plate group, TLR4 levels was lower in the brain (p = 0.023) and higher in the sciatic nerve (p = 0.001) in the magnesium-treated hot plate group. Consequently, the study indicated a single dose of magnesium citrate appeared to cause weakening in the transmission and perception of nociceptive pain. TLR4 may act as a regulator in magnesium's effects on pain perception.

Ionized or Total Magnesium levels, what should we measure in critical ill patients?

Monitoring and measuring magnesium (Mg) values are essential to prevent the development of numerous complications in perioperative medicine and critically ill patients. Although previous studies suggest that measuring free ionized magnesium (iMg) is more useful for estimating Mg status, clinicians currently rely on measurement of total serum magnesium to determine if supplemental magnesium is needed. In this review, we analyzed the recent literature to decide whether it is better to measure ionized serum Mg or total serum Mg when assessing magnesium status, whether iMg predicts clinical outcome, and what are the difficulties in measuring serum iMg levels in intensive care patients and perioperative medicine.