Effects of magnesium sulphate on intraoperative anaesthetic requirements and postoperative analgesia in gynaecology patients receiving total intravenous anaesthesia

Magnesium sulphate improves pulmonary function after video-assisted thoracoscopic surgery: A randomised double-blind placebo-controlled study

BACKGROUND

Reduced lung volumes are unavoidable after lung resection surgery. Magnesium sulphate (MgSO4) administration has been reported to reduce the requirement for neuromuscular blocking drugs and postoperative analgesics in surgical patients.

OBJECTIVE

To investigate the effect of MgSO4 on pulmonary function after video-assisted thoracoscopic surgery (VATS).

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

A university tertiary care centre.

PATIENTS

Sixty-six patients scheduled for pulmonary lobectomy or segmentectomy via VATS.

INTERVENTION

Patients were allocated to one of two groups: the Mg (MgSO4 50 mg kg intravenously for 10 min, followed by a continuous infusion of 15 mg kg h during surgery) or the control (same volume of 0.9% saline).

MAIN OUTCOME MEASURES

Pulmonary function tests [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate] were measured before surgery and at three time points after surgery (2, 24 and 48 h postoperatively) using a portable spirometer. Twelve months after surgery, pulmonary function test values were repeated at a regular outpatient follow-up visit.

RESULTS

FEV1 at 24 (1.7 ± 0.6 vs. 1.3 ± 0.5 l, P = 0.033) and 48 h (1.7 ± 0.6 vs. 1.4 ± 0.5 l, P = 0.021) and FVC at 24 (2.0 ± 0.8 vs. 1.6 ± 0.6 l, P = 0.038) and 48 h (2.2 ± 0.8 vs. 1.7 ± 0.7 l, P = 0.008) after surgery were significantly greater in the Mg group. Patients in the Mg group required less rocuronium than those in the control group (64.2 ± 19.9 vs. 74.9 ± 20.3 mg, respectively; P = 0.041). Consumption of postoperative patient-controlled analgesia was also significantly less at 24 and 48 h after surgery in the Mg group (P = 0.022 and 0.015, respectively), although pain scores and rescue analgesics were comparable. Five patients in the control group were diagnosed with postoperative pneumonia using clinical and radiological criteria before discharge. FEV1 and FVC at 12 months after surgery were not different between the two groups.

CONCLUSION

Intraoperative administration of MgSO4 improved pulmonary function and reduced the need for rocuronium and postoperative analgesics in patients who underwent VATS.

TRIAL REGISTRATION

cris.nih.go.kr identifier: KCT0001410.

Pain Management in the Emergency Department: a Review Article on Options and Methods

CONTEXT

The aim of this review is to recognizing different methods of analgesia for emergency medicine physicians (EMPs) allows them to have various pain relief methods to reduce pain and to be able to use it according to the patient's condition and to improve the quality of their services.

EVIDENCE ACQUISITION

In this review article, the search engines and scientific databases of Google Scholar, Science Direct, PubMed, Medline, Scopus, and Cochrane for emergency pain management methods were reviewed. Among the findings, high quality articles were eventually selected from 2000 to 2018, and after reviewing them, we have conducted a comprehensive comparison of the usual methods of pain control in the emergency department (ED).

RESULTS

For better understanding, the results are reported in to separate subheadings including "Parenteral agents" and "Regional blocks". Non-opioids analgesics such as nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen are commonly used in the treatment of acute pain. However, the relief of acute moderate to severe pain usually requires opioid agents. Considering the side effects of systemic drugs and the restrictions on the use of analgesics, especially opioids, regional blocks of pain as part of a multimodal analgesic strategy can be helpful.

CONCLUSION

This study was designed to investigate and identify the disadvantages and advantages of using each drug to be able to make the right choices in different clinical situations for patients while paying attention to the limitations of the use of these analgesic drugs.

Postanaesthetic shivering - from pathophysiology to prevention

Postoperative shivering is a common complication of anaesthesia. Shivering is believed to increase oxygen consumption, increase the risk of hypoxemia, induce lactic acidosis, and catecholamine release. Therefore, it might increase the postoperative complications especially in high-risk patients. Moreover, shivering is one of the leading causes of discomfort for postsurgical patients. Shivering is usually triggered by hypothermia. However, it occurs even in normothermic patients during the perioperative period. The aetiology of shivering has been understood insufficiently. Another potential mechanism is pain and acute opioid withdrawal (especially with the use of short-acting narcotics). Besides that shivering is poorly understood, the gold standard for the treatment and prevention has not been defined yet. Perioperative hypothermia prevention is the first method to avoid shivering. Many therapeutic strategies for treating shivering exist and most are empiric. Unfortunately, the overall quality of the antishivering guidelines is low. Two main strategies are available: pharmacological and non-pharmacological antishivering methods. The combination of forced-air warming devices and intravenous meperidine is the most validated method. We also analysed different medications but final conclusion about the optimal antishivering medication is difficult to be drawn due to the lack of high-quality evidence. Nevertheless, control of PS is possible and clinically effective with simple pharmacological interventions combined with non pharmacological methods. However, to be consistent with the most up-to-date, evidence-based practice, future antishivering treatment protocols should optimize methodological rigor and transparency.

Attenuation of the pressor responses to laryngoscopy and endotracheal intubation with intravenous dexmedetomidine versus magnesium sulphate under bispectral index-controlled anaesthesia: A placebo-controlled prospective randomised trial

Background and Aims:

Laryngoscopy and intubation cause sympathetic stimulation and arousal reactions. We evaluated the role of dexmedetomidine and magnesium sulphate on pressor responses to laryngoscopy and intubation as compared to placebo, when depth of anaesthesia was maintained at a constant bispectral index (BIS) range 40-50 (±5).

Methods:

One hundred and twenty patients were randomised to receive either dexmedetomidine 1 μg/kg (Group DS), magnesium sulphate 30 mg/kg diluted in 100 ml saline (Group MS) or 100 ml normal saline (Group NS) 15 min before induction of anaesthesia in a double blind manner. After achieving BIS 40–50 (±5), laryngoscopy and intubation were performed. Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded pre-drug, after drug, at intubation, at intervals of 1 min till 5 min, then every 2 min till 10 min and every 10 min for 30 min. Statistical analysis was done using Chi-square test and one way analysis of variance.

Results:

SBP, DBP and HR fell in the DS and MS groups. No significant changes in BP were seen in the NS group at induction and after intubation. HR rose in the NS group (P < 0.001) at induction from 86.35 ± 9.05 to 95.35 ± 11.60 at 2 min. Patients in DS and MS groups had significantly lower HR, SBP and DBP at laryngoscopy and intubation.

Conclusion:

At BIS levels 40-50 (±5) there was no pressor response to intubation in the NS Group. Dexmedetomidine and magnesium sulphate significantly reduced the heart rate and blood pressure from baseline.

The Effect of Intravenous Magnesium Sulfate Versus Intravenous Sufentanil on the Duration of Analgesia and Postoperative Pain in Patients with Tibia Fracture

BACKGROUND

In the recent decades controlling postoperative pain has become a popular topic as it leads to the patients' wellbeing and improved life quality, while it reduces the costs for both patients and medical facilities.

OBJECTIVES

This study aimed at comparing intravenous magnesium sulfate versus intravenous sufentanil on the duration of analgesia and postoperative pain in patients undergoing tibia fracture surgery.

METHODS

This double blind clinical trial study was performed on 70 candidates of tibia fractures between the ages of 18 and 55 years with American society of anesthesiologists (ASA) class I and II. The patients were randomly divided to 2 groups, 1 receiving magnesium sulfate (M) and another receiving sufentanil (S). Both of the groups underwent spinal anesthesia with 10 mg bupivacaine 0.5%. One hour after ensuring the sensorimotor blockade, in the S group 0.1 µg/kg/hour and in the M group 8 mg/kg/hour was diluted in 1 liter of Ringer's solution and infused. In this study, full weakness of the lower limb was considered as the sign of sensorimotor blockade initiation. The postoperative pain intensity was measured using the Visual Analog Scale (VAS), 0, 1, 4, 8, 16, and 24 hours after the end of anesthesia duration. In case of VAS ≥ 3, the patients received 0.3 mg/kg pethidine, intravenously. At last, the time of requesting the first narcotic drug and the total usage of pethidine were recorded.

RESULTS AND CONCLUSIONS

Sufentanil was found to be more effective than magnesium sulfate in reducing postoperative pain and the time of first narcotics request was later in patients receiving sufentanil (P < 0.05).

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.

The Influence of Two Different Doses of Magnesium Sulfate on Intraocular Pressure Variations after Injection of Succinylcholine and Endotracheal Intubation: A Prospective, Randomized, Parallel Three-Arm, Double-blind, Placebo-controlled Clinical Trial

Background:

The use of succinylcholine for rapid sequence induction in patients with open globe injuries may be detrimental to the eye.

Aim:

The aim of this study is to determine if the premedication with magnesium sulfate (MgSO₄) could attenuate the increase in intraocular pressure (IOP) associated with succinylcholine injection and intubation.

Setting:

Operation theaters in a tertiary care University Hospital between December 2014 and July 215.

Design:

This was a prospective, randomized, parallel three-arm, double-blind, placebo-controlled clinical trial.

Participants:

One hundred and thirteen patients’ physical status ASA Classes I and II underwent elective cataract surgery under general anesthesia.

Patients and Methods:

These patients allocated into three groups: Group C (control group) received 100 ml normal saline, Group M1 received 30 mg/kg MgSO₄ in 100 ml normal saline, and Group M2 received 50 mg/kg MgSO₄ in 100 ml normal saline. IOP, mean arterial pressure (MAP), and heart rate (HR) reported at 5-time points related to study drug administration. In addition, any adverse effects related to MgSO₄ were recorded. Intragroup and between-groups differences were examined by analysis of variance test.

Results:

We noticed a significant decrease in IOP in M1 (n = 38) and M2 (n = 37) groups as compared with C group (n = 38) after study drugs infusion, 2 and 5 min after intubation, P < 0.001. While the difference between M1 and M2 groups was insignificant, P = 0.296 and P = 0.647, respectively. There was a significant decrease in MAP and HR in M1 and M2 groups as compared with C group 2 and 5 min after intubation, P = 0.01. While the difference between M1 and M2 groups was insignificant, P = 1.

Conclusion:

MgSO₄ 30 mg/kg as well as 50 mg/kg effectively prevented the rise in IOP, MAP, and HR associated with rapid sequence induction by succinylcholine and endotracheal intubation.

Magnesium sulfate accelerates the onset of low-dose rocuronium in patients undergoing laryngeal microsurgery

STUDY OBJECTIVE

We evaluated the effect of magnesium sulfate-an enhancer of neuromuscular blockade-on onset and duration of low dose of rocuronium, and on operating conditions during laryngeal microsurgery.

DESIGN

Randomized, prospective, double-blinded study.

PATIENTS

Eighty-four patients scheduled for elective laryngeal microsurgery.

INTERVENTIONS

Patients were randomly allocated to receive different doses of rocuronium: 0.6 mg/kg (group C, n=28), 0.45 mg/kg (group LR, n=28), or 0.45 mg/kg plus magnesium sulfate 30 mg/kg (group LM, n=28).

MEASUREMENTS

We measured the onset time and duration of action of rocuronium, and evaluated the surgeon's satisfaction with the operating conditions.

MAIN RESULTS

Group LR showed significantly delayed onset time (group C: 87±22 seconds, group LR: 127±47 seconds, and group LM: 89±32 seconds; P=.001) and maximal suppression than did other groups (group C: 102±30 seconds, group LR: 155±66 seconds, and group LM: 105±36 seconds; P=.002). Duration of action of rocuronium was significantly longer in group C than in other groups (group C: 39±7 minutes, group LR: 28±8 minutes, group LRM: 31±8 minutes; P<.001). Laryngoscope placement score (P=.002), surgeon's satisfaction (P=.005), and sore throat (P=.035) were significantly worse in group LR.

CONCLUSIONS

Magnesium sulfate 30 mg/kg accelerated the onset and improved operating conditions of low-dose rocuronium without prolongation of action.

Magnesium in obstetric anesthesia and intensive care

Magnesium, one of the essential elements in the human body, has numerous favorable effects that offer a variety of possibilities for its use in obstetric anesthesia and intensive care. Administered as a single intravenous bolus dose or a bolus followed by continuous infusion during surgery, magnesium attenuates stress response to endotracheal intubation, and reduces intraoperative anesthetic and postoperative analgesic requirements, while at the same time preserving favorable hemodynamics. Applied as part of an intrathecal or epidural anesthetic mixture, magnesium prolongs the duration of anesthesia and diminishes total postoperative analgesic consumption with no adverse maternal or neonatal effects. In obstetric intensive care, magnesium represents a first-choice medication in the treatment and prevention of eclamptic seizures. If used in recommended doses with close monitoring, magnesium is a safe and effective medication.

Comparison of the effects of magnesium and ketamine on postoperative pain and morphine consumption. A double-blind randomized controlled clinical study

PURPOSE

To compare the effects of magnesium sulfate and ketamine on postoperative pain and total morphine consumption in a placebo-controlled design.

METHODS

One hundred and twenty women scheduled for total abdominal hysterectomy were included in this prospective, randomized, double-blind study. Postoperatively, when the Numeric Pain Rating Scale (NPRS) was four or more, IV-PCA morphine was applied to all patients. The patients were randomized into three groups: Group K ketamine, Group M magnesium, and Group C saline received as infusion. Total morphine consumption for 48h, pain scores, adverse effects, and patients' satisfaction were evaluated.

RESULTS

Total morphine consumption was significantly lower in Group K (32.6±9.2 mg) than in Group M (58.9±6.5 mg) and in Group C (65.7±8.2 mg). The satisfaction level of patients in Group K was higher than the other two groups (p<0.05). Pruritus and nausea were observed more frequently in Group C. CONCLUSİON: The addition of ketamine to IV-PCA morphine reduces the total consumption of morphine without psychotic effects; however, magnesium did not influence morphine consumption.

The effect of intravenous magnesium sulfate infusion on reduction of pain after abdominal hysterectomy under general anesthesia: a double-blind, randomized clinical trial

Background

Post-surgical pain is a physiological response to tissue trauma that produces unpleasant physiological effects with manifestations on various organic systems.

Objective

According to the effect of magnesium sulfate on the N-methyl-d-aspartate (NMDA) receptor, this study examined the effect of magnesium sulfate on the reduction of pain and the mean amount of narcotics consumed by patients after abdominal hysterectomies.

Methods

This double-blind clinical trial study was performed on 60 patients who had undergone abdominal hysterectomies in Shahid Sadoughi Hospital in Yazd, Iran, from 2013 to 2015. The patients were divided randomly into two groups of 30 members each. All of the patients received 2 mg of Midazolam and 2 mcg/kg of Fentanyl as the induction of anesthesia with propofol (2–2.5 mg/kg) and Atracurium 0.5 mg/kg was conducted. All of the patients received 5 mg of intravenous morphine 30 min after induction of anesthesia. Afterwards, the study group received 50 mg/kg of magnesium sulfate in 500 cm³ of Ringer’s serum during the 20 minutes, and 500 cm³ of Ringer’s serum was administered to the members of the placebo group. Visual analogue scale VAS scores were evaluated to reach the minimum difference of 0.8 in mean pain score

Results

The results of this study indicated that the mean pain scores immediately after surgery and at 1, 2, 6, and 12 hr after surgery were lower in the study group than in the placebo group. The mean value of narcotic consumption at all measured time points was higher in the placebo group. No significant differences were found between two groups concerning drug complications.

Conclusion

The results of this study indicated that the intravenous injection of magnesium sulfate can reduce pain, reduce morphine consumption, and reduce the side effects of morphine in patients after surgery.

Funding

This study was funded by Shahid Sadoughi University of Medical Sciences, Yazd, Iran

Clinical trial registration

The trial was registered at the Thai Clinical Trials Registry (http://www.clinicaltrials.in.th) with the registration ID: TCTR20160308001.

Magnesium sulfate improves postoperative analgesia in laparoscopic gynecologic surgeries: a double-blind randomized controlled trial

STUDY OBJECTIVE

The aim of this study is to compare the analgesic effect of intravenous infusion of magnesium sulfate to ketorolac during laparoscopic surgeries.

DESIGN

Double-blind randomized controlled trial.

SETTING

University-affiliated teaching hospital.

PATIENTS

Sixty women submitted to laparoscopic gynecologic oncology surgeries.

INTERVENTIONS

Intravenous ketorolac 30 mg in bolus followed by saline infusion (group K), intravenous magnesium sulfate 20 mg/kg in bolus followed by magnesium 2 mg kg(-1) h(-1) (group M) or intravenous saline solution 20 mL in bolus followed by saline infusion during the entire procedure (group S).

MEASUREMENTS

Postoperative pain, nausea, vomiting, sedation, opioid consumption, time to first dose of analgesic.

MAIN RESULTS

Magnesium sulfate reduced opioid consumption compared with placebo in the postoperative, but not in the intraoperative, period. Nausea, not vomiting, was reduced in ketorolac but not in the magnesium group. Pain intensity was higher in placebo than in the other 2 groups during all periods of observation. In the first 60 minutes, pain intensity was lower in the magnesium than in the ketorolac or the placebo group.

CONCLUSION

Intraoperative magnesium sulfate improves postoperative pain control, acting as an opioid-sparing adjuvant, and is similar to ketorolac 30 mg administered in the beginning of surgery.

The Effect of Intravenous Magnesium Sulfate on Post-Operative Analgesia During Laminectomy

Background and Objectives:

Post-operative pain control is an important concern for both patients and physicians. Magnesium is being used as an adjuvant for anesthesia and analgesia during and after various surgeries. We aimed to investigate the effects of intravenous magnesium sulfate on post-operative analgesia after laminectomy.

Methods Materials:

In this randomized double-blind controlled clinical trial, we enrolled 40 adult patients aged 18-60 with American Society of Anesthesiologists (ASA)  Class I-II who were candidates for elective laminectomy. The patients were randomly assigned in two control groups and were similarly anesthetized. In the case group, after the induction of anesthesia, a loading dose of magnesium sulfate (30 mg/kg) was administered within five to 10 minutes followed by a maintenance dose of 10 mg/kg/hr up to the end of the surgery; while, the patients in the control group received the same volume of saline. After the surgery, all patients received a patient-controlled intravenous analgesia (PCA) pump containing morphine. The first time of using PCA, the amount of consumed morphine during the first 24 hours, and pain score were recorded at 6,12,18 and 24 hours in the post-operative period.

Results:

There was no significant difference between the two groups with respect to the amount of morphine consumed in 24 hours after the surgery (P value =0.23), the first time of using of PCA pump (P value =0.79) and pain intensity (P value=0.52).

Conclusion:

The infusion of Magnesium Sulfate during laminectomy had no effect on patients’ pain and opioid requirement during the first 24 hours after the surgery.

Effects of magnesium sulfate and propofol on the minimum alveolar concentration preventing motor movement in sevoflurane-anesthetized dogs

OBJECTIVE To evaluate the effect of MgSO4, alone and in combination with propofol, on the minimum alveolar concentration preventing motor movement (MACNM) in sevoflurane-anesthetized dogs. ANIMALS 6 healthy purpose-bred adult male Beagles (least squares mean ± SEM body weight, 12.0 ± 1.1 kg). PROCEDURES Dogs were anesthetized 3 times at weekly intervals. The MACNM was measured 45 minutes after induction of anesthesia (baseline; MACNM-B) and was determined each time by use of a noxious electrical stimulus. Treatments were administered as a loading dose and constant rate infusion (CRI) as follows: treatment 1, MgSO4 loading dose of 45 mg/kg and CRI of 15 mg/kg/h; treatment 2, propofol loading dose of 4 mg/kg and CRI of 9 mg/kg/h; and treatment 3, MgSO4 and propofol combination (same doses used previously for each drug). A mixed-model ANOVA and Tukey-Kramer tests were used to determine effects of each treatment on the percentage decrease from MACNM-B. Data were reported as least squares mean ± SEM values. RESULTS Decrease from MACNM-B was 3.4 ± 3.1%, 48.3 ± 3.1%, and 50.3 ± 3.1%, for treatments 1, 2, and 3, respectively. The decrease for treatments 2 and 3 was significantly different from that for treatment 1; however, no significant difference existed between results for treatments 2 and 3. CONCLUSIONS AND CLINICAL RELEVANCE MgSO4 did not affect MACNM, nor did it potentiate the effects of propofol on MACNM. Administration of MgSO4 in this study appeared to provide no clinical advantage as an anesthetic adjuvant.

Comparative Evaluation of Dexmedetomidine and Magnesium Sulphate on Propofol Consumption, Haemodynamics and Postoperative Recovery in Spine Surgery: A Prospective, Randomized, Placebo Controlled, Double-blind Study

PURPOSE

Dexmedetomidine and magnesium sulfate have been used in anesthesia as adjuvant to provide hemodynamic stability and anesthetic agents sparing effect. We compared these effects of dexmedetomidine and magnesium sulfate in spine surgeries.

METHODS

Ninety patients were randomly assigned to three groups. Group D received dexmedetomidine loading dose 1 µg/kg over a period of 15 minutes and maintenance 0.5 µg/kg/h throughout the surgery. Group M received magnesium sulfate loading dose 50 mg/kg over a period of 15 minutes and maintenance 15 mg/kg/h throughout the surgery. Group C received same volume of normal saline. Heart rate (HR) and blood pressure values were recorded at various intervals. The induction and maintenance doses of anesthetics and recovery parameters were also recorded.

RESULTS

Heart rate in group D and group M were significantly decreased (p<0.05) during the whole intraoperative period compared to preoperative values. There was a significant difference in HR values between group C, D and M, during the whole intraoperaive period (p<0.05). Blood pressure values were statistically significantly lower in the group D and group M compared to group C after intubation and all time observations of surgery (p<0.05). Both drugs reduced the anesthetic agent's requirement during surgery. However, the recovery parameters were statistically significant increase with magnesium sulphate compared to dexmedetomidine and control groups.

CONCLUSION

Dexmedetomidine is more effective than magnesium sulfate for maintaining the hemodynamic stability in spine surgeries. Both these drugs also reduce the requirements of anesthetic agents. Recovery from dexmedetomidine is as rapid as control group compared to magnesium sulfate.

Prospective, randomized and controlled trial on magnesium sulfate administration during laparoscopic gastrectomy: effects on surgical space conditions and recovery profiles

BACKGROUND

The degree of neuromuscular blockade is one of the important factors that determine the condition of surgical space during laparoscopic surgery. Magnesium sulfate potentiates the actions of neuromuscular blocking agent, and we hypothesized that intraoperative magnesium sulfate infusion may improve surgical space condition during laparoscopic surgery.

METHODS

Eighty-four patients undergoing elective laparoscopic gastrectomy were randomized to receive isotonic saline (group C) or magnesium sulfate (group M, loading dose with 50 mg/kg over 10 min and then 15 mg/kg/h by continuous infusion) to maintain the moderate neuromuscular blockade using rocuronium. Two experienced surgeons scored the quality of surgical space condition using a 5-point surgical rating scale (SRS). The secondary outcomes included recovery profiles, postoperative pain and adverse events.

RESULTS

The SRS in group M was higher than that of group C. The proportion of patients with a SRS of 5 (optimal) was 2.7 % in the group C and 40.5 % in the group M (P < 0.0001) although a lower amount of rocuronium was required in group M than group C [24.2 (6.5) mg/h for group M vs. 27.5 (6) mg/h for group C; P = 0.017]. Pain after operation site was less severe in group M than in group C at postoperative 24 h (P = 0.009). Recovery profiles and adverse events were similar between the two groups.

CONCLUSION

Intraoperative administration of magnesium sulfate improved the quality of surgical space conditions and decreased neuromuscular blocking agent requirement and postoperative pain in patients undergoing laparoscopic gastrectomy.

MAGnesium-oral supplementation to reduce PAin in patients with severe PERipheral arterial occlusive disease: the MAG-PAPER randomised clinical trial protocol

INTRODUCTION

Magnesium exerts analgaesic effects in several animal pain models, as well as in patients affected by acute postoperative pain and neuropathic chronic pain. There is no evidence that magnesium can modulate pain in patients with peripheral arterial occlusive disease (PAOD). We describe the protocol of a single-centre randomised double-blind clinical trial aimed at assessing the efficacy of oral magnesium supplementation in controlling severe pain in patients with advanced PAOD.

METHODS AND ANALYSIS

Adult patients affected by PAOD at stages III and IV of Lèriche-Fontaine classification, who are opioid-naïve, and who have been admitted to our Acute Pain Service for intractable pain, will be eligible. Patients will be randomised to the control group, treated with standard therapy (oxycodone and pregabalin) plus placebo for 2 weeks, or to the experimental group (standard therapy plus magnesium oxide). Patients will be evaluated on days 0, 2, 4, 6, 8, 12 and 14; the following information will being collected: daily oxycodone dose; average and maximum pain (Numerical Rating Scale); pain relief (Pain Relief Scale); characteristics of the pain (Neuropathic Pain Scale); impact of pain on the patient's daily activities (Brief Pain Inventory). The primary outcome will be oxycodone dosage needed to achieve satisfactory analgaesia on day 14. Secondary outcomes will be pain relief on day 2, time needed to achieve satisfactory analgaesia and time needed to achieve a pain reduction of 50%. A sample size calculation was performed for the primary outcome, which estimated a required sample size of 150 patients (75 per group).

ETHICS AND DISSEMINATION

Ethical approval of the study protocol has been obtained from Comitato Etico Provinciale di Brescia, Brescia, Italy. Trial results will be disseminated through scientific journal manuscripts and scientific conference presentations.

TRIAL REGISTRATION NUMBER

NCT02455726.

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 magnesium sulphate on postoperative analgesia requirements in gynecological surgeries

Objective:

Recent studies have shown the positive effect of magnesium sulphate (MgSO4) on pain reduction and postoperative analgesic requirements in patients undergoing surgery. We assessed the effect of MgSO4 on intra-operative and postoperative analgesic requirements in patients undergoing lower abdominal gynecological laparotomy.

Materials and Methods:

This randomized clinical trial was conducted on 30 female patients at Rasool-e-Akram (referral and academic) hospital in Tehran from August 2012 to March 2013. The patients who were candidates for gynecologic surgeries (hysterectomy and/or myomectomy) were randomized into study (n=15) and control (n=15) groups. Same anesthetic technique was used in all patients. Besides induction of the anesthesia in the study group, we administered MgSO4 50 mg/kg/hr intravenously (IV) for analgesic purposes as a bolus dose and then 8 mg/kg IV as maintenance dose. Control group received the same anesthetic agents and the same amount of isotonic saline instead of MgSO4. Analgesic consumption was measured in both groups postoperatively within 24 hours. The visual analog scale (VAS) was used for the evaluation of postoperative pain in both groups.

Results:

There was a decrease in analgesic consumption and pain in the group receiving MgSO4, in comparison to control group. Pain severity assessment, 24 hours post operatively showed similar results in both groups. There was a statistically significant difference in prescribed dose of pethidine between study and control groups (p=<0.0001).

Conclusion:

Intra-operative MgSO4 is effective in postoperative pain control following lower abdominal laparotomy. Further studies with larger sample sizes and longer follow-up should be performed to obtain more information about safety and to determine whether doses of MgSO4 can provide postoperative analgesic benefits.

Comparison of anesthetic efficacy between lidocaine with and without magnesium sulfate USP 50% for inferior alveolar nerve blocks in patients with symptomatic irreversible pulpitis

INTRODUCTION

The purpose of this prospective, randomized, double-blind, placebo-controlled study was to compare the anesthetic efficacy between lidocaine with and without magnesium sulfate USP 50% for inferior alveolar nerve (IAN) blocks in patients with symptomatic irreversible pulpitis.

METHODS

One hundred patients with symptomatic irreversible pulpitis of mandibular posterior teeth were selected for the study. The patients received 1 mL magnesium sulfate USP 50% or distilled water (placebo) 1 hour before administration of conventional IAN block. Endodontic access cavity preparation was initiated 15 minutes after the IAN block injection. Lip numbness was recorded for all the patients. Success of IAN block was defined as no or mild pain on the visual analogue scale during access cavity preparation and initial instrumentation.

RESULTS

The success rate for the IAN block was 58% for magnesium sulfate group and 32% for the placebo group, with statistically significant difference between the 2 groups (P = .016).

CONCLUSIONS

In mandibular posterior teeth diagnosed with symptomatic irreversible pulpitis, preoperative administration of 1 mL magnesium sulfate USP 50% resulted in statistically significant increase in success of IAN block compared with placebo.

Effect of low-dose (single-dose) magnesium sulfate on postoperative analgesia in hysterectomy patients receiving balanced general anesthesia

Background and Aim. Aparallel, randomized, double blinded, placebo-controlled trial study was designed to assess the efficacy of single low dose of intravenous magnesium sulfate on post-total abdominal hysterectomy (TAH) pain relief under balanced general anesthesia. Subject and Methods. Forty women undergoing TAH surgery were assigned to two magnesium sulfate (N = 20) and normal saline (N = 20) groups randomly. The magnesium group received magnesium sulfate 50 mg·kg⁻¹ in 100 mL of normal saline solution i.v as single-dose, just 15 minutes before induction of anesthesia whereas patients in control group received 100 mL of 0.9% sodium chloride solution at the same time. The same balanced general anesthesia was induced for two groups. Pethidine consumption was recorded over 24 hours precisely as postoperative analgesic. Pain score was evaluated with Numeric Rating Scale (NRS) at 0, 6, 12, and 24 hours after the surgeries. Results. Postoperative pain score was lower in magnesium group at 6, 12, and 24 hours after the operations significantly (P < 0.05). Pethidine requirement was significantly lower in magnesium group throughout 24 hours after the surgeries (P = 0.0001). Conclusion. Single dose of magnesium sulfate during balanced general anesthesia could be considered as effective and safe method to reduce postoperative pain and opioid consumption after TAH.

Magnesium physiology and clinical therapy in veterinary critical care

OBJECTIVE

To review magnesium physiology including absorption, excretion, and function within the body, causes of magnesium abnormalities, and the current applications of magnesium monitoring and therapy in people and animals.

ETIOLOGY

Magnesium plays a pivotal role in energy production and specific functions in every cell in the body. Disorders of magnesium can be correlated with severity of disease, length of hospital stay, and recovery of the septic patient. Hypermagnesemia is seen infrequently in people and animals with significant consequences reported. Hypomagnesemia is more common in critically ill people and animals, and can be associated with platelet, immune system, neurological, and cardiovascular dysfunction as well as alterations in insulin responsiveness and electrolyte imbalance.

DIAGNOSIS

Measurement of serum ionized magnesium in critically or chronically ill veterinary patients is practical and provides information necessary for stabilization and treatment. Tissue magnesium concentrations may be assessed using nuclear magnetic resonance spectroscopy as well as through the application of fluorescent dye techniques.

THERAPY

Magnesium infusions may play a therapeutic role in reperfusion injury, myocardial ischemia, cerebral infarcts, systemic inflammatory response syndromes, tetanus, digitalis toxicity, bronchospasms, hypercoagulable states, and as an adjunct to specific anesthetic or analgesic protocols. Further veterinary studies are needed to establish the frequency and importance of magnesium disorders in animals and the potential benefit of magnesium infusions as a therapeutic adjunct to specific diseases.

PROGNOSIS

The prognosis for most patients with magnesium disorders is variable and largely dependent on the underlying cause of the disorder.

The Effect of Intravenous Magnesium Sulphate Treatment on the Spinal Anaesthesia Produced by Bupivacaine in Pre-eclamptic Patients

OBJECTIVE

In our study, the effect of intravenous magnesium sulphate in normal and pre-eclamptic patients on spinal anaesthesia produced by bupivacaine was investigated.

METHODS

Sixty-four pregnant (32 normal and 32 pre-eclamptic) were accepted in this study. Pregnants were divided into four groups as patients given intravenous magnesium sulphate and as control. Spinal anaesthesia was induced with 12.5 mg 0.5% hyperbaric bupivacaine. Intraoperative and postoperative haemodynamic variables, sensorial block periods, onset times of sensorial and motor block, maximum sensorial block levels, the time to reach maximum block level, Bromage scores, consumptions of intraoperative analgesic and ephedrine, the quality of anaesthesia, the duration of spinal anaesthesia and magnesium levels in blood and cerebrospinal fluid were measured and recorded.

RESULTS

The level of magnesium in blood and cerebrospinal fluid was significantly higher in the group given magnesium in pre-eclamptic patients (p<0.01). Onset of sensory block times were significantly longer in intravenous magnesium group than in groups 1, 2 and 3 (p<0.05). Onset of motor block times were significantly longer and the duration of anaesthesia was shorter in groups given magnesium (p<0.05). Although the quality of anaesthesia was similar, supplemental analgesic consumption was significantly higher in pre-eclamptic pregnants given magnesium sulphate than in pre-eclamptic pregnants who were not given magnesium sulphate (p<0.05).

CONCLUSION

Intravenous magnesium sulphate treatment during the spinal anaesthesia produced by bupivacaine extended the onset of sensory and motor block times, shortened the duration of spinal anaesthesia and therefore led to early analgesic requirement.

Effect of pre-emptive magnesium sulfate infusion on the post-operative pain relief after elective cesarean section

Background:

The aim of this study was to evaluate the analgesic efficacy of pre-operative single dose of intravenous (I.V.) magnesium sulfate infusion in patients undergoing elective Cesarean section.

Materials and Methods:

Seventy pregnant women who underwent elective Cesarean section were randomly divided into two groups. Before induction of anesthesia, the magnesium group (Group A) received magnesium sulfate 50 mg/kg I.V. in bolus dose. The control group (Group B) received the same volume of isotonic saline. The pain scores at rest and also upon movement were evaluated up to 24 h post-operatively and analgesic requirement was recorded during the first 24 h after operation.

Results:

Cumulative analgesic consumption (24 h after operation was 11.2 ± 6.3 mg in group A vs. 13.9 ± 3.9 mg in group B). Post-operative pain scores (24 h after operation was 1.8 ± 2.1 in group A vs. 2.9 ± 1.2 in group B) and shivering incidents (8.57 in group A vs. 14.28 in group B) were significantly lower in Group A (P < 0.05). Mean arterial pressure just after intubation and during the immediate post-operative period was significantly lower in Group A (P < 0.05).

Conclusion:

Pre-operative intravenous magnesium sulfate infusion decrease post-operation pain and requirement of analgesia in Cesarean section.

Ketamine and magnesium association reduces morphine consumption after scoliosis surgery: prospective randomised double-blind study

BACKGROUND

Scoliosis repair is a major orthopaedic surgery associated with severe post-operative pain. Ketamine and magnesium have an established efficacy as morphine-sparing agents. Our purpose was to evaluate the morphine-sparing effect of both magnesium and ketamine given simultaneously compared with ketamine alone during scoliosis surgery.

METHODS

Fifty patients scheduled for posterior instrumentation were randomised in a prospective double-blind study. The Gr (K + Mg) received, after induction, an intravenous (IV) bolus of ketamine 0.2 mg/kg and magnesium 50 mg/kg, followed by continuous infusion of ketamine (0.15 mg/kg/h) and magnesium (8 mg/kg/h) until extubation. The Gr (K) received the same dose of ketamine associated with bolus and continuous infusion of normal saline. All patients received multimodal analgesia associated with IV morphine administered via patient-controlled analgesia pump. Morphine consumption, visual analogue scale (VAS) pain scores and occurrence of side effects were followed until 48 h post-operatively. Sleep quality and patient satisfaction were also followed. P < 0.05 was considered statistically significant.

RESULTS

The average cumulative morphine consumption was significantly lower in the Gr (K + Mg) compared with the Gr (K) at post-operative hours 4, 8, 12, 18, 30, 36 and 48. The relative difference in the post-operative morphine consumption was 29.5%: Gr (K + Mg) 51.53 mg vs. Gr (K) 73.16 mg. VAS scores were not statistically different between the two groups. However, qualities of sleep and satisfaction scores on the first night were significantly better in the Gr (K + Mg) (P = 0.027 and P = 0.016, respectively).

CONCLUSION

Ketamine and magnesium association reduces the post-operative morphine consumption after scoliosis surgery. It seems to provide a better sleep quality and improves patient satisfaction.

The effect of intravenous magnesium sulfate infusion on sensory spinal block and postoperative pain score in abdominal hysterectomy

AIM

The aim of this study was to investigate the effect of i.v. infusion of magnesium sulphate during spinal anesthesia on duration of spinal block and postoperative pain.

METHODS

Forty ASA physical status I and status II, aged between 18 and 65, female patients undergoing abdominal hysterectomy under spinal anesthesia were enrolled in this study. Patients in the magnesium group (Group M, n = 20) received magnesium sulphate 65 mg kg(-1) infusion in 250 mL 5% dextrose at 3.5 mL/min rate, and control group (Group C, n = 20) received at the same volume of saline during operation in a double-blind randomized manner. Duration of sensory and motor block, systolic, diastolic, and mean arterial blood pressures, heart rates, pain scores (VAS values), and side effects were recorded for each patient. Blood and CSF samples were taken for analysis of magnesium concentrations.

RESULTS

Regression of sensorial block was longer in Group M when compared with that in Group C (175 ± 39 versus 136 ± 32 min) (P < 0.01). The VAS scores were lower in Group M than those in Group C at the 2 time points postoperatively (P < 0.01).

CONCLUSION

65 mg kg(-1) of magnesium sulphate i.v. infusion under spinal anesthesia prolongs spinal sensorial block duration and decreases pain VAS scores without complication in patients undergoing abdominal hysterectomy.

Pretreatment of magnesium sulphate improves intubating conditions of rapid sequence tracheal intubation using alfentanil, propofol, and rocuronium - a randomized trial

Background

We investigated the effects of a magnesium sulfate pretreatment on intubating conditions and cardiovascular responses during rapid sequence tracheal intubation (RSI) in this double-blind randomized study.

Methods

Adult patients (n = 154) were randomly allocated to a rocuronium-0.6, rocuronium-0.9, or magnesium group. The magnesium group was pretreated with 50 mg/kg MgSO₄, and the other two groups received the same volume of isotonic saline. Anesthesia was induced with alfentanil, propofol, and either 0.6 mg/kg (rocuronium-0.6 and magnesium groups) or 0.9 mg/kg (rocuronium-0.9 group) rocuronium. An anesthesiologist, blinded to the group assignments, performed RSI and assessed the intubating conditions. Systolic arterial pressure (SAP) and heart rate (HR) were recorded before the magnesium sulfate or normal saline was administered, before anesthesia induction, before intubation, and every minute after intubation for 5 min.

Results

Airway features were similar among the three groups. The intubating conditions were improved significantly in the magnesium group (P < 0.001) compared with the other two groups. Significant increases in SAP at 1 min after intubation were observed in the rocuronium-0.6 and -0.9 groups when compared with the magnesium group (P < 0.05). HR was comparable among the three groups (P > 0.05). No hypertensive episode occurred during the immediate post-intubation period in the magnesium group (P = 0.001), and tachycardia occurred most frequently in the rocuronium-0.6 group (P < 0.05).

Conclusions

MgSO₄ administered prior to RSI using alfentanil, propofol, and rocuronium may improve intubating conditions and prevent post-intubation hypertension.

Magnesium: a versatile drug for anesthesiologists

Magnesium sulfate has been used in preeclampsia patients in order to prevent seizure. It is also used for the treatment of arrhythmia and asthma and as an anesthetic adjunct in patients undergoing surgery for pheochromocytoma. However, its potentiating effects on perioperative analgesia and muscle relaxation have drawn attention recently. These characteristics of magnesium (anesthetic- and analgesic-sparing effect) enable anesthesiologists to reduce the use of anesthetics during surgery and the use of analgesics after surgery. Magnesium sulfate has a high therapeutic index and cost-effectiveness. Considering these diverse characteristics useful for anesthesia, appropriate use of magnesium sulfate would improve surgical outcome and patients' satisfaction.

Perioperative Systemic Magnesium to Minimize Postoperative Pain

Background:

Systemic magnesium has been used to minimize postoperative pain with conflicting results by clinical studies. It remains unknown whether the administration of perioperative systemic magnesium can minimize postoperative pain. The objective of the current investigation was to evaluate the effect of systemic magnesium on postoperative pain outcomes.

Methods:

A wide search was performed to identify randomized controlled trials that evaluated the effects of systemic magnesium on postoperative pain outcomes in surgical procedures performed under general anesthesia. Meta-analysis was performed using a random-effect model. Publication bias was evaluated by examining the presence of asymmetric funnel plots using Egger regression.

Results:

Twenty randomized clinical trials with 1,257 subjects were included. The weighted mean difference (99% CI) of the combined effects favored magnesium over control for pain at rest (≤4 h, −0.74 [−1.08 to −0.48]; 24 h, −0.36 [−0.63 to −0.09]) and with movement at 24 h, −0.73 (−1.37 to −0.1). Opioid consumption was largely decreased in the systemic magnesium group compared with control, weighted mean difference (99% CI) of −10.52 (−13.50 to −7.54) mg morphine IV equivalents. Publication bias was not present in any of the analysis. Significant heterogeneity was present in some analysis, but it could be partially explained by the sole intraoperative administration of magnesium compared with the intraoperative and postoperative administration. None of the studies reported clinical toxicity related to toxic serum levels of magnesium.

Conclusion:

Systemic administration of perioperative magnesium reduces postoperative pain and opioid consumption. Magnesium administration should be considered as a strategy to mitigate postoperative pain in surgical patients.

Effect of palonosetron on postanesthetic shivering after propofol-remifentanil total intravenous anesthesia

PURPOSE

The authors conducted a prospective, randomized, double-blind study to evaluate the anti-shivering efficacy of palonosetron for patients after gynecological laparoscopy under total intravenous propofol-remifentanil anesthesia.

METHODS

Sixty female patients were randomly assigned to one of two groups and administered palonosetron 0.075 mg (palonosetron group, n = 30) or the same volume of normal saline (control group, n = 30) immediately after anesthesia induction. Anesthesia was induced and maintained with propofol and remifentanil, using a target-controlled infusion device. Esophageal and index finger temperatures were measured immediately after anesthesia induction (baseline) and at 15-min intervals until the end of the surgery. Postanesthetic shivering and side effects were assessed in a postanesthetic care unit.

RESULTS

Incidence of shivering was comparable in the control and palonosetron groups (10/30 vs. 8/30, respectively, P = 0.779). No significant intergroup differences were observed between esophageal and index finger temperatures. Compared with baseline values, esophageal temperatures decreased immediately after pneumoperitoneum in the control group and from 30 min after pneumoperitoneum in the palonosetron group.

CONCLUSION

Use of palonosetron (0.075 mg) did not reduce the incidence of postanesthetic shivering after gynecological laparoscopy under propofol-remifentanil anesthesia. Further study including other 5-HT3 antagonists or male patients would elucidate the effect of palonosetron on shivering after propofol-remifentanil anesthesia.

Effect of magnesium sulfate with propofol induction of anesthesia on succinylcholine-induced fasciculations and myalgia

Background:

Magnesium sulfate and propofol have been found to be effective against succinylcholine-induced fasciculations and myalgia, respectively, in separate studies. A prospective randomized double blind controlled study was designed to assess the effect of a combination of magnesium sulfate with propofol for induction of anesthesia on succinylcholine-induced fasciculations and myalgia.

Materials and Methods:

Randomly selected 60 adult patients scheduled for elective surgery under general anesthesia were allocated to one of the two equal groups by draw of lots. The patients of MG Group were pretreated with magnesium sulfate 40 mg/kg body weight in 10 ml volume, while patients of NS group were given isotonic saline 0.9% in the same volume (10 ml) intravenously slowly over a period of 10 min. Anesthesia was induced with fentanyl 1.5 mcg/kg and propofol 2 mg/kg, followed by administration of succinylcholine 2 mg/kg intravenously. Muscle fasciculations were observed and graded as nil, mild, moderate, or severe. Postoperative myalgia was assessed after 24 h of surgery and graded as nil, mild, moderate, or severe. Observations were made in double blind manner.

Results:

Demographic data of both groups were comparable (P > 0.05). Muscle fasciculations occurred in 50% patients of MG group versus in 100% patients of NS group with a significant difference (P < 0.001). After 24 h of surgery, no patient of MG group and 30% patients of NS group had myalgia with a significant difference (P < 0.002).

Conclusion:

Magnesium sulfate 40 mg/kg intravenously may be used with propofol for induction of anesthesia to control succinylcholine-induced fasciculations and myalgia.

Perioperative effects of various anesthetic adjuvants with TIVA guided by bispectral index

Background

This prospective, randomized, double blinded, controlled study was designed to compare effects of intravenous co-administration of clonidine, magnesium, or ketamine on anesthetic consumption, intraoperative hemodynamics, postoperative analgesia and recovery indices during Bispectral Index (BIS) guided total intravenous anesthesia (TIVA).

Methods

After ethical committee approval and written informed consent, 120 adult patients ASA I and II scheduled for open cholecystectomy were randomly assigned to one of 4 equal groups. Group CL received clonidine 3 µg/kg and maintained by 2 µg/kg/h. Group MG received magnesium sulphate 50 mg/kg and maintained by 8 mg/kg/h. Group KET received racemic ketamine 0.4 mg/kg and maintained by 0.2 mg/kg/h. Control group (CT) received the same volume of isotonic saline. Anesthesia was induced and maintained by fentanyl, propofol and rocuronium. Propofol infusion was adjusted to keep the BIS value between 45-55. Intraoperative hemodynamics, induction time, anesthetic consumption, recovery indices, and PACU discharge were recorded.

Results

Induction time, propofol requirements for induction and maintenance of anesthesia, intraoperative fentanyl and hemodynamic values were significantly lower with Groups CL and MG compared to Groups KET and CT (P < 0.05). Patients in Group MG showed significantly lower muscle relaxant consumption, delayed recovery and PACU discharge than other groups (P < 0.05). First, analgesic requirement was significantly longer and total postoperative analgesic consumption was significantly lower in the adjuvant groups versus Group CT (P < 0.05).

Conclusions

Clonidine, magnesium, and ketamine can be useful adjuvant agents to BIS-guided TIVA. Pharmacokinetic studies of such drug combinations were recommended to investigate their interaction.

Effects of valproic acid and magnesium sulphate on rocuronium requirement in patients undergoing craniotomy for cerebrovascular surgery

BACKGROUND

Many anti-epileptics cause resistance to non-depolarizing neuromuscular blocking agents, but this has not been reported for valproic acid (VPA). We hypothesized that VPA would increase the rocuronium requirement and that magnesium sulphate (MgSO(4)) may reduce this increase.

METHODS

Fifty-five patients undergoing cerebrovascular surgeries were studied. Subjects were allocated into three groups at a 1:1:1 ratio: Groups VM, VC, and C. Groups VM and VC were given VPA premedication; Group C was not. A rocuronium injection (0.6 mg kg(-1) i.v.) was administered to Group VM, followed by MgSO(4) as a 50 mg kg(-1) i.v. bolus and 15 mg kg(-1) h(-1) infusion. The same volume of 0.9% saline was administered to the other groups. Supplementary rocuronium (0.15 mg kg(-1)) was given whenever the train-of-four count reached 2. Rocuronium requirements (primary outcome), mean arterial pressure (MAP), heart rate (HR), nausea, vomiting, shivering, and use of anti-emetics and nicardipine were compared.

RESULTS

Group VC showed the highest rocuronium requirement [mg kg(-1) h(-1): 0.47 (0.08) vs 0.33 (0.12) (Group C), 0.31 (0.07) (Group VM); P<0.001]. MAP, intraoperative HR, nausea, vomiting, shivering, and use of anti-emetics and nicardipine were not significantly different among the groups. Postoperative HR was lower in Group VM than in Group VC.

CONCLUSIONS

VPA increased the rocuronium requirement, and MgSO(4) infusion attenuated this increase.

A randomised controlled trial comparing rocuronium priming, magnesium pre-treatment and a combination of the two methods

We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety-two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg(-1) rocuronium; patients in the prime group were given 0.06 mg.kg(-1) rocuronium three minutes before a further dose of 0.54 mg.kg(-1) rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg(-1) magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16)s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid-sequence intubating conditions, compared with either magnesium sulphate or priming used alone.