Comparison of intrathecal magnesium, fentanyl, or placebo combined with bupivacaine 0.5% for parturients undergoing elective cesarean delivery

Magnesium sulfate reduces postoperative pain in women with cesarean section: A meta-analysis of randomized controlled trials

OBJECTIVES

The use of magnesium sulfate (MgSO₄ ) as an adjunct in different anesthetic regimens for cesarean section (CS) delivery often reports conflicting results. This study aimed to review the effectiveness of MgSO₄ on improving postoperative analgesia after CS systematically.

METHODS

PubMed, Embase, and the Cochrane library were searched for randomized controlled trials (RCTs) published from inception to February 2020.

RESULTS

A total of 880 women were included (440 in each group). MgSO₄ had a statistically significant effect compared to the control group on the highest VAS (weighted mean difference [WMD] = -0.74, 95% confidence interval [CI] = -1.03 to -0.46, p < 0.001, I²  = 91.7%, p_{heterogeneity}  < 0.001) and the last VAS (WMD = -0.47, 95% CI = -0.71 to -0.23, p < 0.001, I²  = 95.0%, p_{heterogeneity}  < 0.001). MgSO₄ prolonged the time to the first use of analgesia compared to the control group (standardized mean difference [SMD] = -3.03 min, 95% CI = -4.32 to -1.74, p < 0.001, I²  = 96.3%, p_{heterogeneity}  < 0.001). MgSO₄ decreased the consumption of analgesia compared to the control group (SMD = -3.20 mg of IV morphine equivalent, 95% CI: -5.45 to -0.95, p = 0.005, I²  = 97.6%, p_{heterogeneity}  < 0.001).

DISCUSSION

MgSO₄ decreases the highest VAS in women who underwent general anesthesia, spinal anesthesia, or epidural for CS (all p < 0.05). Additional MgSO₄ significantly reduces postoperative pain in women undergoing CS.

Effect of addition of intrathecal magnesium sulphate to 0.5% hyperbaric bupivacaine and 0.5% isobaric levobupivacaine on duration of analgesia in parturients undergoing elective caesarean section: A prospective randomised study

Background and Aims:

Addition of magnesium sulfate to local anesthetics improves the quality of spinal anesthesia for caesarean section. The aim of this study was to compare the effects of intrathecal 0.5% hyperbaric bupivacaine with 75-mg magnesium sulfate (MgSO₄) and 0.5% isobaric levobupivacaine with 75-mg MgSO₄ on the duration of analgesia in parturients undergoing elective caesarean section.

Material and Methods:

This prospective randomized double-blind parallel-group study was conducted in 60 parturients undergoing elective caesarean section who were randomly allocated to Group I or Group II to receive either 2 ml of 0.5% levobupivacaine with 75-mg MgSO₄ or 2 ml of 0.5% hyperbaric bupivacaine with 75-mg MgSO₄ intrathecally. The duration of postoperative analgesia along with sensory and motor block characteristics and hemodynamics were studied.

Results:

The duration of analgesia did not show a significant difference in the two groups (P = 0.175). The sensory onset time was faster in Group I (3.5 ± 1.3 min) as compared to that in Group II (4.8 ± 2 min; P = 0.004). The onset of motor blockade was not different in the two groups (P = 0.265), but there was a significant delay (P = 0.002) in motor recovery in Group II (267 ± 130.6 min) as compared to Group I (225 ± 85.4 min). Hemodynamics were comparable in the two groups.

Conclusion:

Intrathecal levobupivacaine with MgSO₄ produces a similar duration of postoperative analgesia as compared to hyperbaric bupivacaine with MgSO₄. Early motor recovery allowing early ambulation postoperatively makes isobaric levobupivacaine with MgSO₄ a good alternative for caesarean sections.

The efficacy of ropivacaine and bupivacaine in the caesarean section and the effect on the vital signs and the hemodynamics of the lying-in women

OBJECTIVE

To investigate the efficacy of ropivacaine and bupivacaine in caesarean section and vital signs and the hemodynamics of the lying-in women.

METHODS

A total of 480 lying-in women who were admitted to this hospital for treatment between December 2017 and June 2018 were enrolled into this study as the subjects, which were divided into the experiment group and the control group, with 240 subjects in each group. In the experiment group, subjects received the local anesthesia by infusion of 1.5 mL ropivacaine (0.75%), while those in the control group also took the local anesthesia by infusion of 1.5 mL bupivacaine (0.75%). Thereafter, we observed the differences in the anesthetic efficiency, vital signs and hemodynamics of the lying-in women between two groups.

RESULTS

The excellent and good rates of the anesthesia in two groups were 92.1% and 87.9%, showing no obvious difference; in the experiment group, the average arterial pressures and systolic pressures at 5 min and 10 min after combined spinal and epidural analgesia (CSEA) were all elevated when comparing to the control group (all P < 0.05); in the experiment group, the onset time was obviously extended, while duration of sensory and motor block and the duration of motor block were all shorter than those in the control group (all P < 0.05). During anesthesia, the incidence rate of the adverse reactions in the control group was 2.50%, significantly higher than 0.83% in the experiment group (P < 0.05).

CONCLUSION

Despite that ropivacaine and bupivacaine are efficient in anesthesia in the CSEA in the caesarean section, ropivacaine is more recommended for little influence on the hemodynamics, shorter duration of sensory block and motor block and low incidence rate of adverse reactions, which are conducive to the recovery and also safe to the patients.

Effectiveness of Magnesium in Preventing Shivering in Surgical Patients: A Systematic Review and Meta-analysis

BACKGROUND

Clinical trials regarding the antishivering effect of perioperative magnesium have produced inconsistent results. We conducted a systematic review and meta-analysis with Trial Sequential Analysis to evaluate the effect of perioperative magnesium on prevention of shivering.

METHODS

We searched PubMed, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials, and 2 registry sites for randomized clinical trials that compared the administration of magnesium to a placebo or no treatment in patients undergoing surgeries. The primary outcome of this meta-analysis was the incidence of shivering. The incidence of shivering was combined as a risk ratio with 95% CI using a random-effect model. The effect of the route of administration was evaluated in a subgroup analysis, and Trial Sequential Analysis with a risk of type 1 error of 5% and power of 90% was performed. The quality of each included trial was evaluated, and the quality of evidence was assessed using the Grading of Recommendation Assessment, Development, and Evaluation approach. We also assessed adverse events.

RESULTS

Sixty-four trials and 4303 patients (2300 and 2003 patients in magnesium and control groups, respectively) were included. The overall incidence of shivering was 9.9% in the magnesium group and 23.0% in the control group (risk ratio, 0.42; 95% CI, 0.33-0.52). Subgroup analysis revealed that the incidence of shivering was lower with IV (risk ratio, 0.29; 95% CI, 0.29-0.54; Grading of Recommendation Assessment, Development, and Evaluation, moderate), epidural (risk ratio, 0.24; 95% CI, 0.13-0.43; Grading of Recommendation Assessment, Development, and Evaluation, low), and intrathecal administration (risk ratio, 0.64; 95% CI, 0.43-0.96; Grading of Recommendation Assessment, Development, and Evaluation, moderate). Only trials with low risk of bias were included for Trial Sequential Analysis. The Z-cumulative curve for IV magnesium crossed the Trial Sequential Analysis monitoring boundary for benefit even though only 34.9% of the target sample size had been reached. The Z-cumulative curve for epidural or intrathecal administration did not cross the Trial Sequential Analysis monitoring boundary for benefit. No increase in adverse events was reported.

CONCLUSIONS

Perioperative IV administration of magnesium effectively reduced shivering and Trial Sequential Analysis suggested that no more trials are required to confirm that IV magnesium effectively reduces shivering.

A randomized clinical trial of intrathecal magnesium sulfate versus midazolam with epidural administration of 0.75% ropivacaine for patients with preeclampsia scheduled for elective cesarean section

Background and Aims:

Magnesium sulfate and midazolam have been used as adjuvants to local anesthetics via intrathecal and epidural routes to augment the quality of block and prolong postoperative analgesia. This study compares addition of intrathecal magnesium sulfate versus intrathecal midazolam to epidurally administered isobaric ropivacaine as a part of combined spinal epidural technique in pre-eclamptic parturients undergoing elective cesarean section.

Material and Methods:

After institutional ethics committee approval and written informed consent, 50 pre-eclamptic parturients were randomly allocated to one of the two groups of 25 each to either receive intrathecal magnesium sulfate (50 mg) or intrathecal midazolam (1 mg) in combination with epidural ropivacaine (0.75%; 14–16 ml). The onset and duration of sensory and motor blockade, duration of postoperative analgesia, postoperative visual analogue scores for pain, and perioperative side effects were noted. Data were analyzed statistically using Graphpad.com software.

Results:

Onset times to sensory and motor blockade were faster in midazolam than in magnesium group (P < 0.01). Duration of sensory and motor blockade, and time to first request of analgesia were significantly longer in the magnesium group compared to the midazolam group (P < 0.01). The fetal outcomes according to APGAR scores were comparable in both the groups, the median APGAR score at 1 minute was 8 and at 5 minutes was 10 in both the groups.

Conclusion:

Intrathecal magnesium with epidural ropivacaine significantly prolonged postoperative analgesia compared to intrathecal midazolam without any complications. Perioperative hemodynamics were comparable in both groups.

The Analgesic Efficacy of Intrathecal Bupivacaine and Fentanyl with Added Neostigmine or Magnesium Sulphate

Background

An appropriate anesthesia duration with minimal side effects and prolonged postoperative analgesia are the ideal characteristics of an intrathecal drug used during spinal anesthesia. Neostigmine and magnesium sulphate have been used as spinal anesthetic additives with narcotics and local anesthetics.

Objectives

This study aimed to assess the analgesic properties of intrathecal neostigmine and magnesium sulphate by adding them to intrathecal bupivacaine-fentanyl.

Methods

: In total, 210 patients undergoing tibial fracture surgery were enrolled in a double-blinded clinical trial study. Patients were randomly allocated to one of three groups: group F received 10 mg of bupivacaine and 25 µg of fentanyl as intrathecal drug for spinal anesthesia, group N received 150 µg of neostigmine added to 10 mg of bupivacaine and 25 µg of fentanyl, and group M received 50 mg of magnesium sulphate added to 10 mg of bupivacaine and 25 µg of fentanyl. Analgesia duration, motor blockade scores, postoperative pain scores 6 and 12 hours after surgery, postoperative voiding time, and the incidence of hypotension, bradycardia, respiratory depression, and nausea and vomiting were recorded.

Results

Group M showed significantly longer analgesia duration (330.76 ± 80.98 minutes) than group F (280.98 ± 60.33 minutes). The pain scores in group M 6 hours (NRS: 2.44 ± 0.98) and 12 hours (NRS: 4.10 ± 0.88) after surgery were significantly lower than those of the other two groups. Before discharge from recovery, motor blockade scores and voiding time were not significantly different between the three groups. Hypotension (40%), bradycardia (25%), and nausea and vomiting (70%) were more obvious among group N patients. Respiratory depression did not occur in any patients.

Conclusions

The addition of 50 mg of magnesium sulfate to a bupivacaine–fentanyl solution for intrathecal anesthesia improved the efficacy and duration of the analgesia without any significant side effects. The addition of 150 µg of neostigmine increased the incidence of hypotension, bradycardia, and nausea and vomiting. Moreover, neostigmine failed to prolong analgesia duration.

Neuraxial magnesium sulfate improves postoperative analgesia in Cesarean section delivery women: A meta-analysis of randomized controlled trials

BACKGROUND

We conducted this meta-analysis to elucidate whether additional neuraxial magnesium sulfate (MgSO₄) can improve postoperative analgesia in women undergoing Cesarean section (CS) delivery.

METHOD

We searched Pubmed, Embase and ClinicalTrial.gov. We included only randomized controlled trials that have compared the quality of postoperative analgesia with and without additional neuraxial MgSO₄ in women undergoing CS delivery with neuraxial anesthesia regimens. The primary outcomes included analgesic duration of neuraxial anesthesia, postoperative pain scores and postoperative consumption of analgesics. The secondary outcomes included patients' satisfaction and adverse effects related to postoperative analgesia.

RESULTS

Nine relevant studies comprising a total of 827 women undergoing CS delivery were included. Analyses revealed that CS women receiving additional neuraxial MgSO₄ (the MgSO₄ group) had longer duration of neuraxial anesthesia (effect size [ES] = 1.920, 95% confidence interval [CI] = 0.999 to 2.842, P < 0.001), longer duration of sensory block (ES = 1.020, 95% CI = 0.463 to 1.577, P < 0.001), lower postoperative pain scores at rest (ES = -1.206, 95% CI = -2.084 to -0.329, P = 0.007), pain scores with motion (ES = -1.435, 95% CI = -2.631 to -0.240, P = 0.019) and consumption of analgesics (ES = -1.620, 95% CI = -2.434 to -0.806, P < 0.001) than CS women without receiving additional neuraxial MgSO₄ (the control group). Of note, the MgSO₄ group tended to have higher rate on rating satisfaction as "excellent" than the control group did (odds ratio = 3.748, 95% CI = 2.218 to 6.332, P < 0.001). However, the incidences of adverse effects (i.e., nausea and vomiting, pruritus and hypotension) were not significantly different between these two groups.

CONCLUSION

Neuraxial MgSO₄ improves postoperative analgesia in CS women.

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

Background

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

Methods

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

Results

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

Conclusions

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

Intrathecal magnesium sulfate does not reduce the ED50 of intrathecal hyperbaric bupivacaine for cesarean delivery in healthy parturients: a prospective, double blinded, randomized dose-response trial using the sequential allocation method

Background

Addition of intrathecal magnesium sulfate to local anesthetics has been reported to potentiate spinal anesthesia and prolong analgesia in parturients. The current study was to determine whether intrathecal magnesium sulfate would reduce the dose of hyperbaric bupivacaine in spinal anesthesia with bupivacaine and sufentanil for cesarean delivery.

Methods

Sixty healthy parturients undergoing scheduled cesarean delivery were randomly assigned to receive spinal anesthesia with 0.5% hyperbaric bupivacaine and 5 μg sufentanil with either 0.9% sodium chloride (Control group) or 50% magnesium sulfate (50 mg) (Magnesium group). Effective anesthesia was defined as a bilateral T₅ sensory block level achieved within 10 min of intrathecal drug administration and no additional epidural anesthetic was required during surgery. Characteristic of spinal anesthesia and the incidence of side effects were observed. The ED₅₀ for both groups was calculated using the Dixon and Massey formula.

Results

There was no significant difference in the ED₅₀ of bupivacaine between the Magnesium group and the Control group (4.9 mg vs 4.7 mg) (P = 0.53). The duration of spinal anesthesia (183 min vs 148 min, P < 0.001) was longer, the consumption of fentanyl during the first 24 h postoperatively (343 μg vs 550 μg, P < 0.001) was lower in the Magnesium group than that in the Control group.

Conclusions

Intrathecal magnesium sulfate (50 mg) did not reduce the dose requirement of intrathecal bupivacaine, but can extend the duration of spinal anesthesia with no obvious additional side effects.

Trial registration

This study was registered with Chinese Clinical Trial Registry (ChiCTR) on 15 Jul. 2014 and was given a trial ID number ChiCTR-TRC-14004954.

Comparison of Intrathecal Dexmedetomidine with Morphine as Adjuvants in Cesarean Sections

To compare the effects of intrathecal dexmedetomidine and intrathecal morphine as supplements to bupivacaine in cesarean sections under spinal anesthesia. Full-term parturients (n=120) undergoing elective cesarean sections under spinal anesthesia were randomly allocated into three groups: Group B received 10 mg bupivacaine, Group BD received 10 mg bupivacaine plus 5 µg dexmedetomidine, and Group BM received 10 mg bupivacaine plus 100 µg morphine. The onset and regression time of sensory and motor blockade, postoperative analgesia, and side effects were recorded. Group BD showed quicker onset time and a longer sensory and motor blockade than other groups (BD vs. B and BD vs. BM, p<0.05). The mean time of sensory regression to the S1 segment was 253.21±42.79 min in group BD, 192.50±40.62 min in group BM and 188.33±37.62 min in group B (p<0.001). Group BD showed an analgesia duration (time to requirement of first rescue analgesic) (17.59±6.23 h) similar to that of group BM (16.78±5.90 h) but longer than that of group B (3.53±1.68 h) (p<0.001). The incidence of pruritus was significantly higher in group BM compared with groups BD and B (p<0.001). Less shivering was observed in group BD than in groups BM and B (p=0.009). So intrathecal dexmedetomidine (5 µg) prolonged the motor and sensory blockade, provided a similar analgesic effect and reduced pruritus and shivering compared with morphine (100 µg) in cesarean sections.

The Dose-response of Intrathecal Ropivacaine Co-administered with Sufentanil for Cesarean Delivery under Combined Spinal-epidural Anesthesia in Patients with Scarred Uterus

Background:

Spinal anesthesia is considered as a reasonable anesthetic option in lower abdominal and lower limb surgery. This study was to determine the dose-response of intrathecal ropivacaine in patients with scarred uterus undergoing cesarean delivery under combined spinal-epidural anesthesia.

Methods:

Seventy-five patients with scarred uterus undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled in this randomized, double-blinded, dose-ranging study. Patients received 6, 8, 10, 12, or 14 mg intrathecal hyperbaric ropivacaine with 5 μg sufentanil. Successful spinal anesthesia was defined as a T₄ sensory level achieved with no need for epidural supplementation. The 50% effective dose (ED₅₀) and 95% effective dose (ED₉₅) were calculated with a logistic regression model.

Results:

ED₅₀ and ED₉₅ of intrathecal hyperbaric ropivacaine for patients with scarred uterus undergoing cesarean delivery under combined spinal-epidural anesthesia (CSEA) were 8.28 mg (95% confidence interval [CI]: 2.28–9.83 mg) and 12.24 mg (95% CI: 10.53–21.88 mg), respectively.

Conclusion:

When a CSEA technique is to use in patients with scarred uterus for an elective cesarean delivery, the ED₅₀ and ED₉₅ of intrathecal hyperbaric ropivacaine along with 5 μg sufentanil were 8.28 mg and 12.24 mg, respectively. In addition, this local anesthetic is unsuitable for emergent cesarean delivery, but it has advantages for ambulatory patients.

Comparison of different doses of magnesium sulphate and fentanyl as adjuvants to bupivacaine for infraumbilical surgeries under subarachnoid block

Background and Aims:

Spinal anaesthesia is used for many years for surgeries below the level of umbilicus. It has certain disadvantages such as limited duration of blockade and post-operative analgesia. This study was undertaken to evaluate the effects of additives fentanyl and magnesium sulphate along with bupivacaine during spinal anaesthesia for prolongation of analgesia and motor blockade.

Methods:

This randomised study was conducted in 120 patients of either sex of American Society of Anesthesiologists physical status I and II, posted for infraumbilical surgeries. Patients were randomly allocated to four groups and were given the following drugs intrathecally as per group distribution; group A - bupivacaine 15 mg (0.5% heavy) with fentanyl 25 μg, group B - bupivacaine 15 mg (0.5% heavy) with magnesium 100 mg, group C - bupivacaine 15 mg (0.5% heavy) with magnesium 50 mg and group D - bupivacaine 15 mg (0.5% heavy) with 0.5 ml normal saline. Parameters monitored were duration of analgesia along with haemodynamic parameters and side effects. Data were analysed using the Student's t-test for the continuous variables and two-tailed Fisher exact test or Chi-square test for categorical variables.

Results:

There was significant increase in duration of analgesia in group A (374.37 min) and B (328.13 min) as compared to group C (274.87 min) and D (246.03 min). In group A, all haemodynamic parameters decreased by more than 20%, compared to baseline parameters, which was clinically and statistically significant as compared to other groups. There was also increase in duration of motor blockade in groups A and B.

Conclusion:

Addition of magnesium sulphate at 100 mg dose or fentanyl 25 μg as adjuvants to intrathecal bupivacaine significantly prolongs the duration of analgesia, though in the given doses, magnesium provides better haemodynamic stability than fentanyl, with fewer side effects.

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

Background:

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

Objectives:

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

Patients and Methods:

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

Results:

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

Conclusions:

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

Sparing effects of sufentanil on epidural ropivacaine in elderly patients undergoing transurethral resection of prostate surgery

PURPOSE

This study examined the sparing effect of sufentanil on the median effective concentration (EC₅₀) of epidural ropivacaine in elderly patients undergoing elective transurethral resection of prostate (TURP).

MATERIALS AND METHODS

This was a prospective randomized double-blind dose-response study. Fifty eight elderly patients with American Society of Anesthesiologists physical status I-II who were scheduled for TURP surgery under epidural anesthesia were randomly allocated to a group receiving 15 mL of ropivacaine (group R) or a group receiving ropivacaine plus 5 μg of sufentanil (group RS). The concentration of ropivacaine was determined by a Dixon's up-and-down sequential allocation. The first participant received 0.3% of ropivacaine in both groups and subsequent concentrations were determined by the response of the previous patient in the same group. The EC₅₀ of epidural ropivacaine was analyzed using the Dixon and Massey method.

RESULTS

The EC₅₀ of ropivacaine during TURP surgery was 0.186% (95% confidence interval, 0.173-0.200%) in group R, and 0.136% (95% confidence interval, 0.127-0.144%) in group RS (p<0.01). No differences in Bromage scale of motor block examination and the onset time of sensory block were observed.

CONCLUSION

Administration of 5 μg of epidural sufentanil caused a 37% reduction in the EC₅₀ of epidural ropivacaine in elderly patients who underwent TURP surgery. Thus, sufentanil addition during surgery of TURP can decrease the dose of ropivacaine anesthesia required.

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.

Magnesium Therapy in Pre-eclampsia Prolongs Analgesia Following Spinal Anaesthesia with Fentanyl and Bupivacaine: An Observational Study

BACKGROUND

Magnesium has anti-nociceptive effects and potentiates opioid analgesia following its systemic and neuraxial administration. However, there is no study evaluating the effects of intravenous (IV) magnesium sulphate (MgSO4) therapy on spinal anaesthesia characteristics in severely pre-eclamptic patients.

AIMS

The aim of this study was to compare spinal anaesthesia characteristics in severely pre-eclamptic parturients treated with MgSO4 and healthy preterm parturients undergoing caesarean section. Thus, our primary outcome was regarded as the time to first analgesic request following spinal anaesthesia.

STUDY DESIGN

Case-control Study.

METHODS

Following approval of Institutional Clinical Research Ethics Committee and informed consent of the patients, 44 parturients undergoing caesarean section with spinal anaesthesia were enrolled in the study in two groups: Healthy preterm parturients (Group C) and severely pre-eclamptic parturients with IV MgSO4 therapy (Group Mg). Following blood and cerebrospinal fluid (CSF) sampling, spinal anaesthesia was induced with 9 mg hyperbaric bupivacaine and 20 μg fentanyl. Serum and CSF magnesium levels, onset of sensory block at T4 level, highest sensory block level, motor block characteristics, time to first analgesic request, maternal haemodynamics as well as side effects were evaluated.

RESULTS

Blood and CSF magnesium levels were higher in Group Mg. Sensory block onset at T4 were 257.1±77.5 and 194.5±80.1 sec in Group C and Mg respectively (p=0.015). Time to first postoperative analgesic request was significantly prolonged in Group Mg than in Group C (246.1±52.8 and 137.4±30.5 min, respectively, p<0.001; with a mean difference of 108.6 min and 95% CI between 81.6 and 135.7). Side effects were similar in both groups. Group C required significantly more fluids.

CONCLUSION

Treatment with IV MgSO4 in severe pre-eclamptic parturients significantly prolonged the time to first analgesic request compared to healthy preterm parturients, which might be attributed to the opioid potentiation of magnesium.

Comparative efficacy of two different dosages of intrathecal magnesium sulphate supplementation in subarachnoid block

BACKGROUND

Spinal anaesthesia is the primary anaesthetic technique for many types of surgeries. Adjuncts to the local anaesthetics (LA) used in spinal anaesthesia can exhibit undesirable side-effects like respiratory depression, urinary retention, pruritis, haemodynamic instability and nausea and vomiting, limiting their use. Magnesium when used in therapeutic doses avoids all of these side-effects.

MATERIALS AND METHODS

We conducted a randomized double blind study on 90 patients, 30 in each group, scheduled for orthopaedic lower limb surgery under subarachnoid block. Group I: received bupivacaine (0.5%), 12.5 mg + 0.5 ml of preservative free 0.9% normal saline, Group II received bupivacaine (0.5%), 12.5 mg + 0.2 ml (50 mg) of preservative free 25 % magnesium sulphate + 0.3 ml of preservative free 0.9% normal saline Group III: received bupivacaine (0.5%) 12.5 mg + 0.3 ml (75 mg) of 25 % magnesium sulphate + 0.2 ml of preservative free 0.9% normal saline for subarachnoid block. The onset and duration of sensory block, the highest dermatomal level of sensory block, motor block, time to complete motor block recovery and duration of spinal anaesthesia were recorded.

STATISTICAL ANALYSIS

ANOVA was applied to determine the significance of difference between different groups. If p-value was significant then Turkey's Post Hoc Multicomparison test was applied. Values of p<0.05 were considered to be statistically significant.

RESULTS

The time of maximum sensory block, time of onset of motor block, duration of sensory block, duration of motor block and time of analgesia request were prolonged in patients given magnesium 50mg and 75mg along with local anaesthetic intrathecally.

CONCLUSION

N-methyl-D-aspartate (NMDA) receptor antagonist, magnesium when administered intrathecally along with local anaesthetics prolongs the duration of spinal analgesia without adverse effects.

Effect of intrathecal magnesium in the presence or absence of local anaesthetic with and without lipophilic opioids: a systematic review and meta-analysis

Spinal anaesthesia is the primary anaesthetic technique for many types of surgery. Adjuncts to the local anaesthetics (LA) used in spinal anaesthesia can exhibit undesirable side-effects, limiting their use, but magnesium may have advantages in this respect. We sought randomized control trials (RCTs) in patients undergoing all types of surgery and in women in labour to compare the effect of intrathecal magnesium sulphate ± LA ± lipophilic opioid (experimental group) with the use of either intrathecal lipophilic opioids ± LA or LA only (control group). The primary outcome was the duration of spinal anaesthesia. Secondary outcomes were: onset and time to maximal sensory blockade, onset of motor block, and duration of sensory and motor blockade. We found 15 RCTs comprising 980 patients. The duration of spinal anaesthesia was significantly increased in the experimental group [standardized mean difference (SMD) -1.05 (-1.70, -0.41) (P = 0.001)], compared with the control group. This increased duration of spinal anaesthesia was seen in non-obstetric studies, SMD -1.38 (-2.11, -0.66) (P = 0.0002), but not in obstetric studies, SMD -0.55 (-1.87, 0.77) (P = 0.41). There was no delay in the onset of sensory or motor blockade. The incidence of hypotension and pruritus was similar in both groups. Heterogeneity was high in all outcome measures. The duration of spinal anaesthesia may be increased by the addition of magnesium to lipophilic opioids ± LA.

Drug therapy for preventing post-dural puncture headache

BACKGROUND

Post-dural (post-lumbar or post-spinal) puncture headache (PDPH) is one of the most common complications of diagnostic, therapeutic or inadvertent lumbar punctures. Many drug options have been used to prevent headache in clinical practice and have also been tested in some clinical studies, but there are still some uncertainties about their clinical effectiveness.

OBJECTIVES

To assess the effectiveness and safety of drugs for preventing PDPH in adults and children.

SEARCH METHODS

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 5), MEDLINE (from 1950 to May 2012), EMBASE (from 1980 to May 2012) and CINAHL (from 1982 to June 2012). There was no language restriction.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that assessed the effectiveness of any drug used for preventing PDPH.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because participants' characteristics or assessed doses of drugs were too different in the included studies. We performed an intention-to-treat (ITT) analysis.

MAIN RESULTS

We included 10 RCTs (1611 participants) in this review with a majority of women (72%), mostly parturients (women in labour) (913), after a lumbar puncture for regional anaesthesia. Drugs assessed were epidural and spinal morphine, spinal fentanyl, oral caffeine, rectal indomethacin, intravenous cosyntropin, intravenous aminophylline and intravenous dexamethasone.All the included RCTs reported data on the primary outcome, i.e. the number of participants affected by PDPH of any severity after a lumbar puncture. Epidural morphine and intravenous cosyntropin reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to placebo. Also, intravenous aminophylline reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention, while intravenous dexamethasone increased it. Spinal morphine increased the number of participants affected by pruritus when compared to placebo, and epidural morphine increased the number of participants affected by nausea and vomiting when compared to placebo. Oral caffeine increased the number of participants affected by insomnia when compared to placebo.The remainder of the interventions analysed did not show any relevant effect for any of the outcomes.None of the included RCTs reported the number of days that patients stayed in hospital.

AUTHORS' CONCLUSIONS

Morphine and cosyntropin have shown effectiveness for reducing the number of participants affected by PDPH of any severity after a lumbar puncture, when compared to placebo, especially in patients with high risk of PDPH, such as obstetric patients who have had an inadvertent dural puncture. Aminophylline also reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention in patients undergoing elective caesarean section. Dexamethasone increased the risk of PDPH, after spinal anaesthesia for caesarean section, when compared to placebo. Morphine also increased the number of participants affected by adverse events (pruritus and nausea and vomiting)There is a lack of conclusive evidence for the other drugs assessed (fentanyl, caffeine, indomethacin and dexamethasone).These conclusions should be interpreted with caution, owing to the lack of information, to allow correct appraisal of risk of bias and the small sample sizes of studies.

The analgesic efficacy and safety of neuraxial magnesium sulphate: a quantitative review

Eighteen published trials have examined the use of neuraxial magnesium as a peri-operative adjunctive analgesic since 2002, with encouraging results. However, concurrent animal studies have reported clinical and histological evidence of neurological complications with similar weight-adjusted doses. The objectives of this quantitative systematic review were to assess both the analgesic efficacy and the safety of neuraxial magnesium. Eighteen trials comparing magnesium with placebo were identified. The time to first analgesic request increased by 11.1% after intrathecal magnesium administration (mean difference: 39.6 min; 95% CI 16.3-63.0 min; p = 0.0009), and by 72.2% after epidural administration (mean difference: 109.5 min; 95% CI 19.6-199.3 min; p = 0.02) with doses of between 50 and 100 mg. Four trials monitored for neurological complications: of the 140 patients included, only a 4-day persistent headache was recorded. Despite promising peri-operative analgesic effect, the risk of neurological complications resulting from neuraxial magnesium has not yet been adequately defined.

A comparison of epidural magnesium and/or morphine with bupivacaine for postoperative analgesia after cesarean section

BACKGROUND

Magnesium can potentiate the antinociceptive effect of morphine. This prospective randomized double-blinded study was undertaken to establish the analgesic effect of adding magnesium to epidural morphine during cesarean section.

METHODS

Two hundred patients undergoing cesarean section under combined spinal-epidural anesthesia were recruited. After administration of intrathecal bupivacaine 10mg, patients were randomly assigned to receive one of four epidural study solutions: 0.1% bupivacaine 10 mL (Group B); 0.1% bupivacaine 10 mL and morphine 1.5mg (Group B+Mor); 0.1% bupivacaine 10 mL and magnesium 500 mg (Group B+Mg); or 0.1% bupivacaine 10 mL morphine 1.5mg and magnesium 500 mg (Group B+Mor+Mg). The primary outcome was the area under the curve for visual analog scale pain scores during 36 h postoperatively. Secondary outcomes included time to the use of rescue analgesics, patient satisfaction and side effects.

RESULTS

Patients in Group B+Mor+Mg had lower for pain scores and area under the curve pain scores both at rest and on movement, increased time for first analgesic request, and increased satisfaction score at 24h after surgery.

CONCLUSION

Addition of magnesium 500 mg and morphine 1.5mg to epidural 0.1% bupivacaine 10 mL reduced postoperative pain compared with addition of morphine or magnesium alone or no additive.

To evaluate the efficacy of intrathecal magnesium sulphate for hysterectomy under subarachnoid block with bupivacaine and fentanyl: A prospective randomized double blind clinical trial

BACKGROUND

Intrathecal magnesium has been found to prolong the duration of analgesia in various surgical procedures like lower limb surgeries and as adjuncts to general anesthesia for pain management. The present study was designed to examine whether addition of intrathecal magnesium sulfate would enhance the analgesic efficacy of intrathecal bupivacaine and fentanyl in patients undergoing total abdominal hysterectomy.

METHODS

After taking informed consent, 60 patients were randomised into two groups with 30 patients. Group "S" received 2.5 mL (12.5 mg) of hyperbaric bupivacaine + 0.5 mL (25 mcg) of fentanyl + 0.5 mL of normal saline and Group "M" received 2.5 mL (12.5 mg) of hyperbaric bupivacaine + 0.5 mL (25 mcg) of fentanyl + 0.5 mL (100 mg) of magnesium sulfate. Onset of sensory, motor block and duration of analgesia was noted.

RESULTS

Demographic profile and duration of surgery were comparable (P>0.5). Time of onset of sensory and motor blockade was delayed in Group M compared with Group S, and this was statistically significant. A statistically significant longer duration of analgesia was observed in Group M compared with the control Group S. However, the recovery of motor blockade was found to be statistically insignificant in both the groups. The hemodynamic parameters were comparable in the perioperative period (P>0.05). The incidence of side-effects in both the groups were also comparable (P>0.05).

CONCLUSION

The addition of 100 mg intrathecal magnesium led to prolonged duration of analgesia significantly without increasing the incidence of side-effects. Also, there was a significant delay in the onset of both sensory and motor blockade.

Comparison of postoperative analgesic effect of intrathecal magnesium and fentanyl added to bupivacaine in patients undergoing lower limb orthopedic surgery

OBJECTIVE

To compare the analgesic efficacy and side effects of magnesium and fentanyl as an additive to intrathecal bupivacaine.

METHODS

Ninety adult patients scheduled for femur surgery under spinal anesthesia were randomly allocated to one of the following three groups to receive intrathecally: bupivacaine 15 mg combined with 0.5 mL magnesium 10%; bupivacaine 15 mg combined with 0.5 mL fentanyl; or bupivacaine 15 mg combined with 0.5 mL distilled water (control). The time to first analgesic request, sensory and motor blockade onset time, duration of sensory and motor blockade, analgesic requirement in the first 12 hours after surgery, and the incidences of hypotension, bradycardia, hypoxemia and ephedrine were recorded.

RESULTS

Magnesium caused a significant delay in the onset of both sensory and motor blockade compared with the fentanyl (95% CI 3 to 4; p < 0.001) and control (95% CI 3.5-5; p < 0.001) groups. The duration of spinal analgesia in group F (fentanyl) was significantly greater than in group C (control) (95% CI 365-513; p < 0.001) and group M (magnesium) (95% CI 385-523; p < 0.001). The total amount of methadone consumption over 12 hours was significantly lower in the magnesium and fentanyl groups than in the control group (5 mg vs. 5.666 ± 1.728 mg; p = 0.04).

CONCLUSION

Addition of intrathecal magnesium sulfate to spinal anesthesia induced by bupivacaine significantly prolonged the onset of both sensory and motor blockade compared with fentanyl. Although magnesium failed to prolong the time to first analgesic requirement as seen with fentanyl, it reduced the total consumption of opioids in the first 12 hours postoperatively compared with the control group.

Effects of adjunct intrathecal magnesium sulfate to bupivacaine for spinal anesthesia: a randomized, double-blind trial in patients undergoing lower extremity surgery

PURPOSE

The aim of this study was to evaluate the effect of additional magnesium sulfate (MgSO(4)) 100 mg to intrathecal (IT) isobaric 0.5% bupivacaine 3 ml on spinal anesthesia in patients undergoing lower extremity orthopedic surgery.

METHODS

In a double-blind randomized clinical trial, 79 American Association of Anesthesiologists (ASA) I or II adult patients undergoing lower extremity orthopedic surgery were recruited. The patients were randomly allocated to receive 100 mg MgSO(4) 5% (0.2 ml) plus 15 mg of bupivacaine 0.5% (MgSO(4) group) or 15 mg bupivacaine 0.5% combined with 0.2 ml normal saline (control group) intrathecally. Response to treatment was assessed as onset and duration of sensory block, the highest level of sensory block, time to complete motor block recovery, duration of spinal anesthesia, and postoperative analgesic requirement.

RESULTS

The onset of the sensory block was slower in the MgSO(4) group than in the control group (13.3 vs. 11.6 min, P = 0.04), and the duration of the sensory blockade was significantly longer in the MgSO(4) group than the control group (106.5 vs. 85.5 min, P = 0.001). Total analgesic requirements for 24 h following surgery were lower in the MgSO(4) group than in the control group (96.8 vs. 138.5 mg, P = 0.001). Mean duration of spinal anesthesia was not significantly different between two groups (178.0 vs. 167.4 min, P = 0.23).

CONCLUSION

In patients undergoing lower extremity surgery with spinal anesthesia, the addition of 100 mg IT MgSO(4) to 15 mg bupivacaine without opioid supplement, prolonged the duration of the sensory block, decreased postoperative analgesic consumption, and significantly prolonged the onset of spinal anesthesia.

Is magnesium sulfate by the intrathecal route efficient and safe?

The polypharmacological approach to the treatment of postoperative pain has become routine in an attempt to minimize the adverse side effects of opioids. Magnesium sulphate is a noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptor and thus can modify nociceptive modulation. Intravenous administration of magnesium sulphate can improve postoperative analgesia and decrease the requirement for postoperative opiates, but the effects are inconsistent and have not been reliably accompanied by a reduction in the incidence of morphine-related adverse events. Several studies have shown that the administration of magnesium by the intrathecal route is safe and, in combination with opiates, extends the effect of spinal anaesthesia in both animal and human studies. The analysis of these studies justifies further investigation of the use of magnesium sulphate by the intrathecal route.

Intrathecal sufentanil decreases the median effective dose (ED50) of intrathecal hyperbaric ropivacaine for caesarean delivery

BACKGROUND

The addition of opioid to local anaesthetics has become a well-accepted practice of spinal anaesthesia for caesarean delivery. Successful caesarean delivery anaesthesia has been reported with the use of a low dose of intrathecal hyperbaric ropivacaine coadministered with sufentanil. This prospective, double-blinded study determined the median effective dose (ED50) of intrathecal hyperbaric ropivacaine with and without sufentanil for caesarean delivery, to quantify the sparing effect of sufentanil on the ED50 of intrathecal hyperbaric ropivacaine.

METHODS

Sixty-four parturients undergoing elective caesarean delivery with combined spinal-epidural anaesthesia were randomized into two groups: Group R (ropivacaine) and Group RS (ropivacaine plus sufentanil 5 microg). The initial dose of ropivacaine was 13 mg in Group R and 10 mg in Group RS. The effective dose was defined as a T(6) level attained within 10 min and no supplemental epidural anaesthetic required during surgery. Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the dose of ropivacaine for the next patient using an up-down sequential allocation.

RESULTS

The ED50 of intrathecal ropivacaine was 11.2 mg [confidence interval (CI) 95%: 11.0-11.6] in Group R vs. 8.1 mg (CI 95%: 7.8-8.3) in Group RS. Motor block was markedly more intense in Group R than in Group RS, and the incidence of shivering was lower in Group RS than in Group R. There were no differences in the onset time of sensory block or motor block, in the incidence of hypotension, nausea and vomiting.

CONCLUSION

Intrathecal sufentanil 5 microg produced a 28% reduction of ED50 of intrathecal hyperbaric ropivacaine for caesarean delivery.

Intravenous magnesium sulfate for post-operative pain in patients undergoing lower limb orthopedic surgery

INTRODUCTION

This study looks at the effect of supplementary intravenous magnesium sulfate on acute pain when administered in patients undergoing lower limb orthopedic surgery using spinal anesthesia with bupivacaine.

METHOD AND MATERIALS

In this double-blind, randomized, placebo-controlled clinical trial, 60 patients were selected and randomly divided into two groups. Efforts were made to place both groups under the same method of anesthesia. One group received 8 mg/kg intravenous magnesium sulfate, started before the incision and continued up to the end of the surgical procedure, using a 50 ml syringe, via a peripheral large bore catheter; the second group received the same volume of placebos using the same method. To present the results, mean (+/- SD) was used; a P value of <0.05 was considered significant.

RESULTS

There was no difference between the two groups in terms of the basic variables. Pain reported by the first group that received magnesium sulfate was significantly less at the first, third, sixth and 12th hours after the operation in comparison with the group that received placebo. Also, the intravenous morphine requirements in the first 24 h after the surgery were less in the magnesium group (4.2 +/- 1.6 mg) than in the control group (9.8 +/- 2.1 mg).

CONCLUSION

Intravenous magnesium sulfate can serve as a supplementary analgesic therapy to suppress the acute post-operative pain, leading to less morphine requirements in the first 24 h.