Effect of continuous magnesium sulfate infusion on spinal block characteristics: A prospective study

Effects of intraoperative Magnesium sulfate infusion on emergency agitation during general anesthesia in patients undergoing radical mastectomy: a randomized controlled study

BACKGROUND

Emergency agitation is a common postoperative complication in patients under general anesthesia, which can lead to unpredictable damages such as shedding of drainage tube and bleeding from the wound. The purpose of the study is to investigate whether intraoperative infusion of Magnesium Sulfate reduces the incidence of emergency agitation (EA) in patients undergoing radical mastectomy, and to evaluate its safety and efficacy.

METHODS

A total of 70 patients were randomly assigned to two groups: the Magnesium group (M group) and the control group (C group). After a routine intravenous anesthetic induction, patients in the M group received a 30 mg/kg bolus of intravenous magnesium during the first hour and then a continuous infusion of 10 mg/kg ×h until the end of the surgery, patients in the C group received 0.9% saline at the same volume and rate. The sedation-agitation scale (SAS) and the visual analogue scale were used to assess agitation and pain, respectively.

RESULTS

Compared to the C group, the M group reduced the incidence of EA significantly (odds ratio 0.26, 95% confidence interval 0.09-0.71, P = 0.009). The postoperative pain score of the magnesium sulfate group(0(0,1)) was lower than that of the control group(2(0,3)) at T0 (P = 0.011). Additionally, the M group required a lower dosage of remifentanil during surgery compared to the C group(300.4 ± 84 versus 559.3 ± 184 µg, respectively, P<0.001).

CONCLUSIONS

the intraoperative infusion of magnesium sulfate is a safe and effective method for reducing the incidence of emergency agitation in patients undergoing radical mastectomy.

TRAIL REGISTRATION

The study was registered in Chictr.org with the identifier: ChiCTR2300070595 on 18/04/2023.

Intravenous magnesium sulphate in standing horses: effects on physiological parameters, plasma concentration of magnesium and nociceptive threshold tests

A bolus of 50 mg kg ^-1 MgSO₄ (treatment Mg) or the same volume of saline (treatment S) was infused over 15 minutes in 5 adult healthy horses. T0 was the end of the infusion. Physiological parameters were recorded throughout the study period. Measurements of electrical, thermal and mechanical nociceptive thresholds were performed at the pelvic limbs at baseline (before T0), and at specific timepoints. Blood samples were taken at fixed timepoints before, during and until 12 hours after the infusion. For statistical analysis, the 95% confidence intervals (CI's) for the differences in nociceptive thresholds between treatments were calculated. Physiological parameters were compared using a linear mixed model (global α = 0.05, with Bonferroni correction α = 0.0125). The concentrations of ions were also compared with baseline values at specific timepoints, using a linear mixed model. The Pearson's correlation coefficient was derived between the ion concentrations. The 95% CI's of thermal, mechanical and electrical thresholds were [-1; +2]°C, [0; +3] N and [-1; +1] mA (positive differences indicate higher thresholds for treatment Mg), respectively. Heart rate was significantly higher (p < 0.0001) and non-invasive systolic arterial pressure (p < 0.0001) and respiratory rate (p = 0.0002) significantly lower after treatment Mg compared to treatment S. Additionally, non-invasive systolic arterial pressure was significantly different at T45 (p < 0.001). Although mild changes in cardiovascular parameters and plasma concentrations were seen with intravenous administration of MgSO₄, no changes in nociceptive thresholds were detected in standing non-sedated horses.

Analgesic and hemodynamic effects of intravenous infusion of magnesium sulphate versus dexmedetomidine in patients undergoing bilateral inguinal hernial surgeries under spinal anesthesia: a randomized controlled study

BACKGROUND

Spinal anesthesia is commonly employed during inguinal hernial surgeries. Its short duration may, however, be considered a limitation, especially for bilateral hernial repair. The aim of this research is to investigate the analgesic and hemodynamic effects of intravenous infusion of both MgSO₄ and dexmedetomidine on patients undergoing bilateral inguinal hernia surgeries under spinal anesthesia.

METHODS

This study was a prospective, randomized, double-blinded controlled trail. It included 60 male patients who had been scheduled for bilateral elective inguinal hernia surgery under spinal anesthesia at Kasr Al-Aini hospital. Patients were randomly allocated to one of three groups (n = 20 each) to receive 50 mL of 0.9% saline intravenous infusion of either dexmedetomidine 0.5 μg.kg^-1. h^-1 (Group D) or magnesium sulphate 15 mg.kg^-1. h^-1 (Group M) or normal saline (Group S). The primary outcome of this study was set as the total duration of analgesia. Secondary outcomes were set as the onset and duration of sensory and motor blockade, perioperative hemodynamics, and the total 24-hour postoperative morphine consumption.

RESULTS

Durations of sensory and motor blockades as well as durations of analgesia were all significantly longer among patients in Group D (mean 2.2, 3.5, 5.8 hours respectively) and Group M (mean 2.2, 3.3, 5.2 hours respectively), in comparison to Group S (mean 1.5, 2.7, 3.9 hours respectively). No significant differences were found in systolic or diastolic arterial blood pressure, heart rate oxygen saturation, cardiac output, or stroke volume among the study groups. Seven patients in Group D and four patients in Groups M and S developed hypotension.

CONCLUSION

Intravenous infusion of either dexmedetomidine or MgSO₄ with spinal anesthesia effectively improves the quality of spinal anesthesia and prolongs the duration of postoperative analgesia and decreases the 24-hour postoperative morphine consumption. Results also demonstrated that the use of dexmedetomidine resulted in a slightly longer duration of analgesia, whilst the use of MgSO₄ resulted in slightly better hemodynamic stability.

Intravenous magnesium sulfate for postoperative analgesia after abdominal hysterectomy under spinal anesthesia: a randomized, double-blind trial

Background and objectives

Abdominal Hysterectomy (AH) is associated with significant inflammatory response and can result in moderate to severe postoperative pain. This study aimed to evaluate the efficacy of magnesium infusion in reducing postoperative pain and analgesic consumption after AH under spinal anesthesia with Intrathecal Morphine (ITM).

Method

Eighty-six patients were included in this clinical, controlled, randomized, double-blind study. Patients received in Group Mg, MgSO₄ 50 mg kg⁻¹ for 15 minutes followed by 15 mg kg⁻¹ h⁻¹ until the end of the surgery; and in Group C, (control) the same volume of isotonic saline. Both groups received 100 μg of ITM. All patients received dipyrone + ketoprofen intraoperatively and postoperatively, and dexamethasone intraoperatively only. We evaluated the intensity of pain, tramadol consumption, and adverse events 24 hours postoperatively.

Results

Serum magnesium concentrations were higher in Group Mg at the end, and one hour after the operation (p = 0.000). Postoperative pain scores were reduced in Group Mg at 6 hours at rest and on movement (p < 0.05). Tramadol consumption did not show a statistically significant difference between Group Mg and Group C (15.5 ± 36.6 mg and 29.2 ± 67.8 mg respectively, p = 0.53). Hemodynamic variables, the incidence of pruritus, nausea, and vomiting were similar in the two groups.

Conclusion

Infusion of MgSO₄ during AH undergoing spinal anesthesia with ITM reduced at 6 hours at rest and on movement. More studies should be performed to evaluate the potential antinociceptive effect of MgSO₄ in scenarios where a multimodal analgesia approach was employed.

Comparison of Magnesium Sulfate and Ketamine with Ropivacaine in Supraclavicular Brachial Plexus Block: A Randomized Controlled Trial

Background:

Supraclavicular brachial plexus block offers good operating conditions with limited postoperative analgesia. Magnesium sulfate (MgSO₄) and ketamine block peripheral nociception mediated via N-methyl-D-aspartate receptors.

Aims:

The aim of this study was to evaluate the effect of MgSO₄ and ketamine on the duration of analgesia in brachial block.

Settings and Design:

This was a prospective, randomized, controlled double-blind study.

Materials and Methods:

One hundred and five adult patients were randomly divided into three groups: Group I = 27 mL of 0.5% ropivacaine; Group II = 27 mL of 0.5% ropivacaine + 250 mg MgSO₄; and Group II = 27 mL of 0.5% ropivacaine + 2 mg.kg⁻¹ ketamine. Normal saline was added to make a total volume of 30 mL. The onset and duration of the sensorimotor blockade, quality and duration of postoperative analgesia, and adverse effects were assessed.

Statistical Analysis:

Statistical analysis was performed using SPSS, version 17.0 software (SPSS, Inc., Chicago, IL, USA). Chi-square test was used for nonparametric and ANOVA for parametric data. Post hoc Student's paired t-test was applied wherever indicated. The results were expressed as mean and standard deviation or numbers (%). P < 0.05 was considered as statistically significant.

Results:

The duration of analgesia was significantly longer in Group II (8.78 ± 0.97 h) compared to Group I (6.76 ± 0.92 h; P < 0.001) and Group III (7.1 ± 0.89 h; P < 0.001). Intervention groups had lower postoperative visual analog scores at 8, 12, and 24 h compared to the control group. Sedation, nystagmus, and hallucinations were observed in Group III.

Conclusion:

The addition of MgSO₄ to ropivacaine in supraclavicular brachial plexus block significantly prolongs the duration of analgesia. MgSO₄ improves the quality of postoperative analgesia with lesser incidence of side effects when compared to ketamine.

Effect of Intervenous Magnesium Sulfate on Decreasing Opioid Requirement after Surgery of the Lower Limb Fracture by Spinal Anesthesia

Background:

Magnesium is the calcium natural physiological antagonist; it also antagonizes N-Methyl-D-aspartate receptors, therefore, providing antinociceptive properties. The reason for effective role of treatment with magnesium on decreasing opioid usage, less dissatisfaction, and good sleep quality is proposed theoretically yet. This study aimed to evaluate the effect of magnesium sulfate on decreasing opioids requirement after surgery of the lower limbs fracture by spinal anesthesia.

Methods:

A total of 60 patients aged from 45 to 75 years with the lower limb fractures (femur and hip) candidate for surgery by spinal anesthesia. In a randomized double-blind method, patients were divided into two groups as Magnesium Group (M) and Control Group (C). Group M received a bolus of 5 mg/kg magnesium sulfate plus (250 CC) normal saline and Group C received (250 CC) normal saline in the same condition.

Results:

Pain score and the physical dissatisfaction were reduced at 12, 24, and 48 h after surgery in Group M as compared with Group C (P = 0.000). Total opioid requirement at the end of 48 h and at the first 24 h after surgery were reduced in Group M as compared with Group C (P = 0.001). The endurance of spinal block was increased in Group M as compared with Group C (P = 0.000).

Conclusions:

A low dose of magnesium sulfate reduced the pain score, opioid requirement, and physical dissatisfaction while increased endurance of spinal block.

Use Profile of Magnesium Sulfate in Anesthesia in Brazil

Objectives: The use of magnesium sulfate in the perioperative period has several benefits, including analgesia, inhibition of the release of catecholamines and prevention of vasospasm. The aim of this survey was to provide an overview of the use of magnesium sulfate in anesthesia. Method: This was a prospective descriptive cross-sectional study. An online questionnaire was sent to 9,869 Brazilian anesthesiologists and trainees. The questionnaire comprised closed questions mainly regarding the frequency, clinical effects, adverse events, and doses of magnesium sulfate used in anesthesia. Results: Of the 954 doctors who responded to the survey, 337 (35.32%) reported using magnesium sulfate in anesthesia. The most commonly cited clinical effects for the use of magnesium sulfate in anesthesia were (n/%): postoperative analgesia (245/72.70%), reduction of anesthetic consumption (240/71.21%) and prevention and treatment of preeclampsia and seizures in eclampsia (220/65.28%). The most frequently reported adverse events were hypotension (187/55.48%), residual neuromuscular blockade (133/39.46%), hypermagnesemia (30/8.90%), and intravenous injection pain (26/7.71%). The intravenous doses of magnesium sulfate used in most general anesthesia inductions were between 30 and 40 mg.kg-1. Conclusions: Magnesium sulfate is an important adjuvant drug in the practice of anesthesia, with several clinical effects and a low incidence of adverse events when used at recommended doses.

Magnesium interscalene nerve block for the management of painful shoulder disorders

Shoulder pain is a common and distressing disorder. Systemic multimodal analgesia may be ineffective, but interscalene nerve block provides effective therapy. Magnesium may increase the efficacy and duration of systemic or regional analgesia. This case series examines the utility of magnesium interscalene nerve block for the management of painful shoulder disorders. Six elderly patients with shoulder pain and dysfunction received interscalene nerve block with injection of bupivacaine and magnesium. The patients subsequently reported significant improvement in sleep, shoulder pain, and physical function for 16 weeks. This report highlights that magnesium interscalene nerve block provides safe, effective, and prolonged shoulder analgesia.

Whether preventive low dose magnesium sulphate infusion has an influence on postoperative pain perception and the level of serum beta-endorphin throughout the total abdominal hysterectomy

OBJECTIVE

Due to the known role of preventive low dose magnesium sulphate on postoperative pain management, in this randomized, double-blinded, placebo-controlled study, we tried to investigate the possible relationship between low dose intra-operative magnesium sulphate infusion, postoperative analgesia and the level of serum beta-endorphin during total abdominal hysterectomy under general anesthesia.

METHODS

Forty women undergoing total abdominal hysterectomy were randomly allocated into 2 groups (20 in each arm). Fifteen minutes before induction of anaesthesia, the case group received a continuous intravenous infusion of magnesium sulphate (15mg/kg/h) and placebo control group received the same volume of isotonic saline. Pain scores were assessed at 0, 6, 12, and 24h after operations using Verbal Numeric Rating Scale. Pethidine consumption was recorded precisely. Serum level of beta-endorphin just 15min before the induction and at the end of the operations was determined by ELISA technique.

RESULTS

At 6 and 12h after the operations, Verbal Numeric Rating Scale in the case group was significantly lower than that of placebo control group (P=.0001). Over 24h after the operations, pethidine consumption was significantly lower in the case group compared with control group (P=.0001). In the case group, serum level of beta-endorphin was significantly decreased at the end of the operations compared with before the induction (P=.04).

CONCLUSION

We illustrated that preventive low dose intra-operative magnesium sulphate infusion reduces postoperative pain, has opioid sparing effect and declines serum beta-endorphin concentration during total abdominal hysterectomy.

Evaluation of Magnesium as an adjuvant in Ropivacaine-induced supraclavicular brachial plexus block: A prospective, double-blinded randomized controlled study

Objective:

Different additives have been used to prolong brachial plexus block. We evaluated the effect of adding magnesium sulfate to ropivacaine for supraclavicular brachial plexus blockade. The primary endpoints were the onset and duration of sensory and motor block and duration of analgesia.

Methods:

One hundred patients (25–55 years) posted for elective forearm and hand surgeries under supraclavicular brachial plexus block were divided into two equal groups (Groups RM and RN) in a randomized, double-blind fashion. In group RM (n = 50), 30 ml 0.5% ropivacaine plus 150 mg (in 1 ml 0.9% saline) magnesium sulfate and in group RN (n = 50), 30 ml 0.5% ropivacaine plus 1 ml normal saline were administered in supraclavicular block. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative visual analog scale (VAS), hemodynamic variables, and side effects were recorded for each patient.

Findings:

Though with similar demographic profile and block (sensory and motor) onset time, the sensory and motor block duration and time to first analgesic use were significantly longer and the total need for rescue analgesics was lower in group RM (P = 0.026) than group RN. Postoperative VAS values at 24 h were significantly lower in group RM (P = 0.045). Intraoperative hemodynamics was comparable among two groups and no appreciable side effect was noted throughout the study period.

Conclusion:

It can be concluded from this study that adding magnesium sulfate to supraclavicular brachial plexus block may increase the sensory and motor block duration and time to first analgesic use, and decrease total analgesic needs, with no side effects.