Magnesium sulphate: an adjuvant to tracheal intubation without muscle relaxation--a randomised study

The impact of magnesium on shivering incidence in cardiac surgery patients: A systematic review

Background and objective

This scientific review involves a sequential analysis of randomized trial research focused on the incidence of shivering in patients undergoing cardiac surgery. The study conducted a comprehensive search of different databases, up to the end of 2020. Only randomized trials comparing magnesium administration with either placebo or no treatment in patients expected to experience shivering were included. The primary objective was to evaluate shivering occurrence, distinguishing between patients receiving general anesthesia and those not. Secondary outcomes included serum magnesium concentrations, intubation time, post-anesthesia care unit stay, hospitalization duration, and side effects. Data collection included patient demographics and various factors related to magnesium administration.

Material and methods

This scientific review analyzed 64 clinical trials meeting inclusion criteria, encompassing a total of 4303 patients. Magnesium was administered via different routes, primarily intravenous, epidural, and intraperitoneal, and compared against placebo or control. Data included demographics, magnesium dosage, administration method, and outcomes. Heterogeneity was assessed using the I2 statistic. Some studies were excluded due to unavailability of data or non-responsiveness from authors.

Result

and discussion: Out of 2546 initially identified articles, 64 trials were selected for analysis. IV magnesium effectively reduced shivering, with epidural and intraperitoneal routes showing even greater efficacy. IV magnesium demonstrated cost-effectiveness and a favorable safety profile, not increasing adverse effects. The exact dose-response relationship of magnesium remains unclear. The results also indicated no significant impact on sedation, extubation time, or gastrointestinal distress. However, further research is needed to determine the optimal magnesium dose and to explore its potential effects on blood pressure and heart rate, particularly regarding pruritus prevention.

Conclusion

This study highlights the efficacy of intravenous (IV) magnesium in preventing shivering after cardiac surgery. Both epidural and intraperitoneal routes have shown promising results. The safety profile of magnesium administration appears favorable, as it reduces the incidence of shivering without significantly increasing costs. However, further investigation is required to establish the ideal magnesium dosage and explore its potential effects on blood pressure, heart rate, and pruritus prevention, especially in various patient groups.

Comparison of Magnesium Pre-treatment With Two Different Doses of Rocuronium in Rapid Sequence Intubation: A Randomized Controlled Trial

Introduction Magnesium is recognized for its ability to reduce the onset time of rocuronium while simultaneously extending its duration of action. This study aims to assess the efficacy of magnesium pre-treatment in decreasing the onset time with two different doses of rocuronium in patients undergoing rapid sequence intubation. Materials and methods This randomized prospective double-blind clinical study involved 50 patients classified as American Society Of Anesthesiologists (ASA) I/II, with no preoperative indications of difficult intubation, undergoing elective surgery under general anesthesia. The patients were divided into two groups: group A received 60 mg/kg of magnesium 15 minutes before intubation with 1.2 mg/kg of rocuronium, and group B received 60 mg/kg of magnesium before 0.6 mg/kg of rocuronium. Intubating conditions were assessed and graded at loss of last twitch after administration in both groups, considering ease of intubation, vocal cord position, and response to the insertion of the tracheal tube. Simultaneously, hemodynamic variations were recorded just before intubation, at one minute and five minutes post-intubation. Results Intubating conditions with 0.6 mg/kg of rocuronium were comparable or equally good compared to 1.2 mg/kg of rocuronium with magnesium pre-treatment. Conclusions Magnesium pre-treatment enhances the neuromuscular blocking effect of rocuronium, reducing its onset time without clinically significant prolongation of the duration of the block.

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.

Magnesium sulfate administration in difficult laryngoscopy: An effective and safe method

PURPOSE

Difficult laryngeal exposure during laryngeal microsurgery and laser surgery is a major concern for otolaryngologists. This study evaluated the efficacy and safety of magnesium sulfate administration in difficult laryngeal exposure patients.

STUDY DESIGN

Quasi-experimental design.

MATERIALS AND METHODS

Forty adult patients scheduled for laryngeal microsurgery with difficult laryngeal exposure according to Cormack-Lehane (CL) classification were included. Magnesium sulfate 50% (20-30 mg/kg) was administered as a bolus injection. Laryngeal exposure and hemodynamic stability were evaluated before and after the intervention.

RESULTS

CL grading was shown a statistically significant improvement after magnesium sulfate administration. There are no clinically significant changes in the mean arterial pressure, heart rate, and oxygen saturation levels in the patients who received magnesium sulfate for better laryngeal exposure.

CONCLUSION

Magnesium sulfate is an effective and safe drug for better viewing in difficult laryngeal exposure patients.

Effects of magnesium sulphate on the onset time of rocuronium at different doses: a randomized clinical trial

Background and aims

Rocuronium may provide excellent onset time, but high doses are required for effective action. Several strategies have managed to shorten rocuronium onset time, including the use of Magnesium Sulphate (MgSO₄).

Methods

One hundred and eighty patients were randomized into six groups according to rocuronium dose received (0.3, 0.6 or 1.2 mg.kg^-1) and the administration of saline or MgSO⁴ (60 mg.kg^-1). Correlations between tissue perfusion and rocuronium onset time was determined by variations in perfusion index.

Results

Median (quartiles) rocuronium onset times were 85.5 (74.0–92.0); 76.0 (52.0–87.0) and 50.0 (41.0–59.5) seconds for 0.3, 0.6 mg.kg^-1 and 1.2 mg.kg^-1 doses, respectively. MgSO₄ decreased rocuronium onset at doses of 0.3 mg.kg^-1 (60.0 [48.0–74.3] seconds) and 0.6 mg.kg^-1 (44.0 [39.0–49.0] seconds) but not at 1.2 mg.kg^-1 (38.0 [33.5–56.3] seconds) (p < 0.001). Perfusion index variations in groups that received MgSO₄ were greater than in controls. A negative correlation between shorten onset and increased perfusion index was observed in rocuronium doses of 0.3 mg.kg^-1 (r = -0.50; p < 0.001) and 0.6 mg.kg^-1 (r = -0.424; p < 0.001), but not for 1.2 mg.kg^-1 dose (r = -0.25; p = 0.07).

Conclusion

MgSO₄ reduces rocuronium onset time at doses of 0.3 mg.kg^-1 and 0.6 mg.kg^-1 being that the latter has a similar effect when compared to the dose of 1.2 mg.kg^-1, with or without the use of MgSO₄.

Trial registry at

http://www.ensaiosclinicos.gov.br/

Registry Number

RBR-96CY3K

Antitussive effect of a magnesium infusion during anesthetic emergence in patients with double-lumen endotracheal tube: a randomized controlled trial

Background

A double-lumen endotracheal tube (DLT) inserted into the bronchus can stimulate the respiratory tracts, causing coughing. Opioids have been introduced to prevent emergence cough. However, the administration of a significant opioid dose at the end of surgery may result in undesirable events. Magnesium, common intracellular ion, suppress bronchial smooth muscle contraction and have antitussive effect. We investigated the antitussive effects of a magnesium infusion during anesthetic emergence in patients who underwent thoracic surgery requiring one-lung ventilation (OLV) anesthesia with a DLT.

Methods

One-hundred forty patients undergoing OLV anesthesia with a DLT were enrolled in this prospective, randomized double-blinded trial. In combination with a low dose of remifentanil, patients were randomly allocated to receive either magnesium sulphate (infusion of 15 mg/kg/hour after a single bolus of 30 mg/kg) or normal saline during the operation and emergence. Primary outcomes were the severity and incidence of cough during emergence.

Results

The severity of cough was assessed by the cough severity grading score: 0, no cough; 1, single cough; 2, cough persistence <5 seconds; 3, cough persistence ≥5 seconds. There was a significant difference in the severity score of cough between the groups [median (IQR): 2 (0 to 3) in control group vs. 0 (0 to 1) in magnesium group, P=0.003]. However, there was no significant difference in the overall incidence of cough between both groups [42 (64.6%) in control group vs. 31 (47.7%) in magnesium group, P=0.077].

Conclusions

Magnesium attenuated the severity of cough during emergence after OLV anesthesia using a DLT without adverse events.

[Effectiveness of magnesium sulfate compared to rocuronium for rapid sequence tracheal intubation in adults: clinical randomized trial]

INTRODUCTION AND OBJECTIVES

Magnesium sulfate has been used in anesthesia because it has relevant clinical features such as: analgesia, autonomic response control and muscle relaxation. Using the agent to establish adequate conditions for tracheal intubation remains controversial. The aim of the study was to compare the effectiveness of magnesium sulfate and rocuronium for rapid sequence tracheal intubation in adults.

METHODS

Double blind, randomized, unicentric, prospective study assessed 68 patients, ASA 1 or 2, over 18 years, scheduled for appendectomy under general anesthesia. Patients were divided into two groups. GM patients received 50 mg.kg^-1magnesium sulfate and GR patients, 1 mg.kg^-1 rocuronium immediately before anesthesia induction. Arterial Blood Pressure (BP) and Heart Rate (HR) were measured in both groups at five times related to the administration of the drugs studied. The primary variable was the clinical status of tracheal intubation.

TRIAL REGISTRY

RBR-4xr92k.

RESULTS

GM was associated with no significant hemodynamic parameter change after injection. GM showed 85% (29/34) poor intubation clinical status, 15% (5/34) good, and 0% excellent (< 0.0001).

CONCLUSION

Magnesium sulfate did not provide adequate clinical status when compared to rocuronium at a dose of 50 mg.kg^-1 for rapid sequence intubation in adult patients.

Effectiveness of magnesium sulfate compared to rocuronium for rapid sequence tracheal intubation in adults: clinical randomized trial

Introduction and objectives

Methods

Trial Registry

Results

Conclusion

Magnesium sulfate reduces the rocuronium dose needed for satisfactory double lumen tube placement conditions in patients with myasthenia gravis

Background

Using a minimum dose of neuromuscular blockade (NMB) to achieve intubation condition is one of the goals in anaesthesia management of patients with myasthenia gravis (MG) for thoracoscopic (VATS) thymectomy. However, tracheal intubation with double lumen tube (DLT) could be challenging if intubation condition is not optimal. This double-blind randomised controlled study was designed to investigate whether magnesium sulfate would reduce the rocuronium dose needed for DLT intubation and improve the DLT placement condition for patients with MG who were scheduled for video-assisted thoracoscopic (VATS) thymectomy.

Methods

Recruited patients were randomly assigned to receive magnesium sulfate 60 mg.kg^− 1 or normal saline (control) prior to the administration of NMB. Titrating dose of rocuronium was administered to achieve train of four (TOF) ratio less than 10% before DLT intubation. The primary outcome was the rocuronium dose required to achieve TOF ratio less than 10%. The secondary outcome was intubation condition for DLT placement.

Results

Twenty-three patients had received magnesium sulfate and 22 patients had received normal saline before rocuronium administration. The required rocuronium dose [mean (standard deviation)] were 0.10 (0.05) mg.kg^− 1 and 0.28(0.17) mg.kg^− 1 in patients who had magnesium sulfate and normal saline respectively(P < 0.0001). With a similar depth of neuromuscular blockade and depth of anaesthesia, 100% of patients in the magnesium sulfate group and 72.7% of patients in the control group showed excellent intubation condition (P = 0.027) respectively. The patients in both groups had similar emergence characteristics.

Conclusions

Magnesium sulfate is associated with a decrease in rocuronium requirement for an optimal DLT intubation condition in patients with MG for VATS thymectomy.

Trial registration

Clinical Trial Registry of China (http://www.chictr.org.cn) identifier: ChiCTR-1800017696, retrospectively registered on August 10, 2018.

Preparing for the unexpected: special considerations and complications after sugammadex administration

Sugammadex, a modified gamma-cyclodextrin, has changed clinical practice of neuromuscular reversal dramatically. With the introduction of this selective relaxant binding agent, rapid and reliable neuromuscular reversal from any depth of block became possible. Sugammadex can reverse neuromuscular blockade without the muscarinic side effects typically associated with the administration of acetylcholinesterase inhibitors. However, what remained unchanged is the incidence of residual neuromuscular blockade. It is known that sugammadex cannot always prevent its occurrence, if appropriate dosing is not chosen based on the level of neuromuscular paralysis prior to administration determined by objective neuromuscular monitoring. Alternatively, excessive doses of sugammadex administered in an attempt to ensure full and sustained reversal may affect the effectiveness of rocuronium in case of immediate reoperation or reintubation. In such emergent scenarios that require onset of rapid and reliable neuromuscular blockade, the summary of product characteristics (package insert) recommends using benzylisoquinolinium neuromuscular blocking agents or a depolarizing agent. However, if rapid intubation is required, succinylcholine has a significant number of side effects, and benzylisoquinolinium agents may not have the rapid onset required. Therefore, prior administration of sugammadex introduces a new set of potential problems that require new solutions. This novel reversal agent thus presents new challenges and anesthesiologists must familiarize themselves with specific issues with its use (e.g., bleeding risk, hypermagnesemia, hypothermia). This review will address sugammadex administration in such special clinical situations.

Comparison of the trapezius and the adductor pollicis muscle as predictor of good intubating conditions: a randomized controlled trial

Background

Adequate muscle relaxation is important for ensuring optimal conditions for intubation. Although acceleromyography of the adductor pollicis muscle is commonly used to assess conditions for intubation, we hypothesized that acceleromyography of the trapezius is more indicative of optimal intubating conditions. The primary outcome was the difference between both measurement sites with regard to prediction of good or acceptable intubating conditions.

Methods

Neuromuscular blockade after injection of rocuronium 0.3 mg/kg IV was measured simultaneously with acceleromyography of the adductor pollicis muscle and the trapezius muscle in sixty female patients, American Society of Anesthesiologists physical status I to III, undergoing general anesthesia for gynecologic surgery. Exclusion criteria were: expected difficult tracheal intubation (e.g. history of difficult intubation, reduced mouth opening (< 2 cm) and/or Mallampati Score 4), increased risk of pulmonary aspiration (e.g. gastroesophageal reflux or delayed gastric emptying) allergies to drugs used during the study, pregnancy, neuromuscular diseases, medication with potential to influence neuromuscular function (e.g. furosemide, magnesium, cephalosporins) and hepatic or renal insufficiency (serum bilirubin >26 μmol/L, serum creatinine >90 μmol/l). Patients were randomized to 2 groups: group A (n = 30): endotracheal intubation after onset of the neuromuscular block at the adductor pollicis muscle. Group B (n = 30): endotracheal intubation after onset at the trapezius muscle. Intubating conditions were compared between both groups by means of a standardised score (the Copenhagen score) with Fisher’s exact test.

Results

Onset of the block after rocuronium injection was observed at the adductor pollicis muscle compared to the trapezius with 2.8 (1.1) versus 2.5 (1.1) min (mean ± SD; P = 0.006). Intubating conditions were poor in 2 patients (7%) of group A, and in 1 patient (3%) of group T. They were acceptable (either excellent or good) in 28 patients (93%) in group A, and in 1 patient (97%) in group T (P = 0.82).

Conclusions

Performing acceleromyography at the trapezius muscle reduced the time between injection of neuromuscular blocking agents and intubation by 18 s (11%). Thus, trapezius muscle acceleromyography is an acceptable alternative to adductor pollicis muscle acceleromyography in predicting acceptable intubating conditions, which allows for earlier indication of adequate intubating conditions.

Trial registration

ClinicalTrial.gov Identifier: NCT01849198. Registered April 29, 2013.

The role of magnesium sulfate in tracheal intubation without muscle relaxation in patients undergoing ophthalmic surgery

Background:

Muscle relaxant agents usually use to facilitate tracheal intubation; however, sometimes limitations exist. Magnesium (Mg) sulfate is a candidate for muscle relaxant substitute. This study was designed to determine the effect of Mg sulfate accompanied with propofol and fentanyl in patients undergoing ophthalmic surgery.

Materials and Methods:

In a double-blind randomized protocol and before tracheal intubation, Mg sulfate 40, 45, or 50 mg/kg in 100 ml of saline (Groups 1–3, respectively) or saline alone (Group 4) were administrated intravenously in 100 patients (n = 25 in each group) with the American Society of Anesthesiologist (ASA) physical Status I, II, or III. The patients' intubation condition in all subjects were determined and described.

Results:

The patients' demographic data including age, ASA, systolic and diastolic blood pressures, intraocular pressure, and body mass index were not significantly different between the groups. A better mask ventilation feasibility in Mg sulfate 45 group (Group 2) was observed when compared with Mg sulfate 50 (Group 3) (P = 0.022) and saline group (Group 4) (P = 0.021). In addition, the vocal cord movement and muscle relaxant requirement in saline group were significantly different from others groups (P < 0.05). The laryngoscopic time in saline group was greater than other groups significantly (P < 0.0001).

Conclusion:

Intravenous administration of Mg sulfate accompanied with propofol and fentanyl facilitates the tracheal intubation without neuromuscular blocking agents. To avoid Mg level increasing in plasma; however, the low dose of Mg sulfate is suggested.

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.

Efficacy of Sugammadex for the Reversal of Moderate and Deep Rocuronium-induced Neuromuscular Block in Patients Pretreated with Intravenous Magnesium

Background:

Magnesium enhances the effect of rocuronium. Sugammadex reverses rocuronium-induced neuromuscular block. The authors investigated whether magnesium decreased the efficacy of sugammadex for the reversal of rocuronium-induced neuromuscular block.

Methods:

Thirty-two male patients were randomized in a double-blinded manner to receive magnesium sulfate (MgSO4) 60 mg/kg or placebo intravenously before induction of anesthesia with propofol, sufentanil, and rocuronium 0.6 mg/kg. Neuromuscular transmission was monitored using TOF-Watch SX® acceleromyography (Organon Ltd., Dublin, Ireland). In 16 patients, sugammadex 2 mg/kg was administered intravenously at reappearance of the second twitch of the train-of-four (moderate block). In 16 further patients, sugammadex 4 mg/kg was administered intravenously at posttetanic count 1 to 2 (deep block). Primary endpoint was recovery time from injection of sugammadex to normalized train-of-four ratio 0.9. Secondary endpoint was recovery time to final T1.

Results:

Average time for reversal of moderate block was 1.69 min (SD, 0.81) in patients pretreated with MgSO4 and 1.76 min (1.13) in those pretreated with placebo (P = 0.897). Average time for reversal of deep block was 1.77 min (0.83) in patients pretreated with MgSO4 and 1.98 min (0.58) in those pretreated with placebo (P = 0.572). Times to final T1 were longer compared with times to normalized train-of-four ratio 0.9, without any difference between patients pretreated with MgSO4 or placebo.

Conclusion:

Pretreatment with a single intravenous dose of MgSO4 60 mg/kg does not decrease the efficacy of recommended doses of sugammadex for the reversal of a moderate and deep neuromuscular block induced by an intubation dose of rocuronium.

Anesthetic management of a patient with Marfan syndrome and severe aortic root dilatation undergoing cholecystectomy and partial hepatic resection

Due to high mortality associated with aortic dissection, anesthetic management of patients with Marfan syndrome with severe aortic root dilation is a challenging situation. We describe the anesthetic management of a patient with Marfan syndrome with severe aortic root dilation, who required major surgery like cholecystectomy with partial liver resection under general anesthesia. A 47-year-old female presented to pre-anesthetic clinic for cholecystectomy with partial hepatic resection for gall bladder carcinoma. Clinical features, transthoracic echocardiography and computed tomography of thorax supported a diagnosis of Marfan syndrome with severely dilated aortic root. Aortic dissection in patients with Marfan syndrome and severely dilated aortic root can be precipitated by major hemodynamic changes under anesthesia. Careful hemodynamic monitoring and avoidance of hemodynamic swings can prevent this life-threatening event.