• Users Online: 2477
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 20  |  Issue : 1  |  Page : 72-84

A comparative study between magnesium sulfate and dexmedetomidine as adjuvants to bupivacaine using ultrasound-guided lumbar-plexus block in lower abdominal surgeries


Anesthesiology and Intensive Care, AL-Azhar University, Assiut, Egypt

Date of Submission29-Aug-2021
Date of Decision13-Sep-2021
Date of Acceptance19-Sep-2021
Date of Web Publication4-Mar-2022

Correspondence Address:
Nayera A.H Mohamed
Anesthesiology and Intensive Care, AL-Azhar University, Elminia, Postal Addresss: 61511
Egypt
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/azmj.azmj_100_21

Rights and Permissions
  Abstract 


Background and aim Pain international association of described pain as an unpleasant sensory and emotional practice accompanied with actual or potential tissue injuries. Opioid administrations remain the cornerstone of postoperative pain relief, but it may cause significant side effects, including sedations, nausea, vomiting, and urinary retention. We aimed to compare the efficacy of ultrasound-guided lumbar-plexus block through adding magnesium sulfate and dexmedetomidine (DEX) to bupivacaine on postoperative analgesia and thereafter surgical operation.
Patients and methods This prospective, randomized, double-blinded, controlled research was performed on Al-Azhar University Hospitals. A total of 75 cases of both sexes, age between 21 and 65 years, American Society of Anesthesiologists class I– II, were listed for elective lower-abdomen surgical operation underneath general anesthesia.
Results Pain scores were decreased significantly in the study groups for 12 and 18 h in BM and BD, respectively, also, there was a significant decrease at 2, 4, 6, 8, and 12 h in the BD group lesser than the BM group postoperatively. The time to the initial analgesic appeal was significantly extended in the BD group (11.9±1 h) than the BM group (10.6±0.7 h).
Conclusion Posterior lumbar-plexus block utilizing 22 ml of bupivacaine 0.5% with DEX 1 μg/kg decreases pain score, opioid consumption, prolongs duration of analgesia, better hemodynamics stability, and perfect outcome of cases’ satisfaction postoperatively compared with posterior lumbar-plexus block using 22 ml of bupivacaine 0.5% with magnesium sulfate 150 mg. DEX provides faster onset time and longer periods of MB and extended period of analgesia with smaller consumptions of postoperative rescue analgesia.

Keywords: dexmedetomidine, magnesium sulfate, ultrasound-guided lumbar-plexus block


How to cite this article:
AbdAlsalam MA, Mohamed NA. A comparative study between magnesium sulfate and dexmedetomidine as adjuvants to bupivacaine using ultrasound-guided lumbar-plexus block in lower abdominal surgeries. Al-Azhar Assiut Med J 2022;20:72-84

How to cite this URL:
AbdAlsalam MA, Mohamed NA. A comparative study between magnesium sulfate and dexmedetomidine as adjuvants to bupivacaine using ultrasound-guided lumbar-plexus block in lower abdominal surgeries. Al-Azhar Assiut Med J [serial online] 2022 [cited 2022 Jun 29];20:72-84. Available from: http://www.azmj.eg.net/text.asp?2022/20/1/72/339061




  Introduction Top


Pain is an unpleasant sensory and emotive practice accompanied with actual or potential tissue damages. Postoperative pains are the main problem for early postoperative ambulation and rise the risk of DVT and respirational complication and extend the hospitalization. So, aggressive perioperative pain prevention can yield to avoid these complications that can pose a challenge to anesthesia providers [1].

Ultrasound (US) became the more favored device for locating nerve’s structure to achieve plexus and nerve blocks. The developments of US are emphasized in comparison with ‘conventional’ nerve blocks via electric nerve stimulations and US is desirable to progress effectiveness and decrease the complication of plexus blocks [2],[3].

Local anesthetic medications are extensively utilized through the anesthetic field, but the restricted period of action of different local anesthetics is the obstacle for anesthetists. A variety of perineural adjuvants were tried to shorten the onset and extend the period of analgesia of nerve blocks. The familiarity of pain mechanism has emphasized the function of central sensitizations and N-methyl-D-aspartate (NMDA) receptors in postoperative pains [4].

Magnesium sulfate (MgSO4) is the NMDA-receptor adversary that was assessed as an adjunct to local anesthetics in the neuraxial blocks and marginal nerve blocks [5].

Dexmedetomidine (DEX) is an alpha-2 adrenergic receptor agonist with elevated discernment that administered as a short-term calm and analgesia agent in ICUs [6],[7]. Combining DEX with local anesthetic is an effective method to advance the efficiency of local anesthetic and to reduce its needed dose [8].


  Aim Top


Primary outcome:
  1. Time to the first postoperative analgesic requirement.
  2. Postoperative analgesic requirement.


Secondary outcome:
  1. Postoperative visual analog pain score.
  2. Time of discharge of postanesthetic care unit.
  3. Incidence of any side effect.



  Patients and methods Top


This prospective, randomized, double-blinded, controlled work was performed out in Al-Azhar Assiut University Hospital in the period from January 2019 to June 2021 after agreement from the hospital ethical committee, and all cases were informed about the procedure and its possible consequence and written informed consents were obtained, the type of the study was randomized, prospective, and double blinded. A total of 75 cases of both sexes, American Society of Anesthesiologists (ASA) grades I–II, aged between 21 and 65, were scheduled for elective lower-abdominal surgical operation.

Cases with the subsequent criteria were exempted from work: coagulation abnormalities, on anticoagulant therapy, allergy to local anesthetics (amide group) or to study medications, severe renal or hepatic derangement, failed block, failure to perform lumbar-plexus block, uncooperative cases, neuromuscular diseases, sinus bradycardia or atrioventricular block, mental disorders, and infection at the nerve-block site.

Case groups: the cases were randomized and divided into three parallel equal groups (25 cases in each group) via a computer-made table and the randomizing sequence was covered in sealed-envelope assignments held by a supervisor who did not participate in the clinical management or data collections. The patient, the anesthetist, and the staff who provided the intraoperative and postoperative care were blinded to the group allocation.

Group B (control group): received US-guided injection of lumbar-plexus block using a bolus injection of isobaric bupivacaine hydrochloride 0.5% (20 ml), Sunny bupivacaine 0.5% vial 20 ml: 5 mg in each 1 ml (Sunny Pharmaceuticals, Egypt)+(in 2 ml of 0.9% normal saline), total volume 22 ml.

Group BM: received US-guided injection of lumbar-plexus block using a bolus injection of isobaric bupivacaine hydrochloride 0.5% (20 ml)+MgSO4 150 mg (MgSO4 100 mg, Magnisol Ampoule Memphis) in 2 ml of 0.9% normal saline, total volume 22 ml.

Group BD: received US-guided injection of lumbar-plexus block using a bolus injection of isobaric bupivacaine hydrochloride 0.5% (20 ml)+DEX (Precedex vial 100 μg/ml, Hospira Inc., Lake forest, USA). About 1 μg/kg (in 2 ml of 0.9% normal saline), total volume 22 ml.

Preoperative management

A careful medical history, through physical examination, including central nervous system, chest, heart, abdomen, lower limbs and back, and necessary investigations were done. We explained to the cases how to assess their own postoperative pain intensity via a 10-point linear visual analog scale (VAS), scored from 0 to 10 (where 0=no pains and 10=the worst pains). To score VAS, use a ruler, the score is calculated by measurement of the distance (mm) on the 10-cm line amid the ‘no pain’ anchor and the case’s marks.

Anesthetic management

On arrival to the operational theater, standard monitoring was used counting 5-lead ECG, noninvasive blood pressure, and pulse oximetry via Dräger Infinity Vista XL Case Monitor (USA). Then, basal mean arterial blood pressure (MAP), heart rate (HR), and oxygen saturation (SaO2) were recorded, then a 20-G intravenous cannula was injected and the cases received 300 ml of 0.9% saline, and all cases that received the similar anesthetic technique were premeditated by intravenous midazolam 0.05 mg/kg and fentanyl 1 μg/kg. Inductions of anesthesia were accomplished by 2 mg/kg of 1% propofol trailed by atracurium 0.5 mg/kg to simplify tracheal intubations with a suitable-size cuffed endotracheal tube. Anesthesia has been preserved with inhalational isoflurane (MAC1 in O2) and atracurium bolus 0.1 mg/kg. Ventilations were controlled with tidal size of 6–8 ml/kg and breathing rate of 12–14 breaths per minute. The ventilating factors were adapted to have end-tidal CO2 at 30–35 mmHg with PEEP of 5 cmH2O and O2 flow of 5 l/min. After completion of the surgical operation, lumbar-plexus block has been done by the anesthetist with the case fibbed in cross-location. The skin was wipped with chlorhexidine in isopropyl alcohol and was enclosed with sterile fenestrated sheets. The probe was wrapped with a sterile covering. The skin and subcutaneous tissues was penetrated with 2% lidocaine 2 ml before supplement of the 25-G needle, 90-mm length.

Shamrock method

The curvilinear probe was positioned axially in the flank of the patient directly cephalad to the iliac top. The probe was posteriorly moved till the crosswise procedure of vertebra L4 and the quadrates lumborum, erector spinae, and psoas main muscles was recognized as a shamrock or 3-leaved clover. The probe tail was tilted cephalad, targeted the hyperechoic lumbar plexus amid the thin back, and the thick frontal lamina of the psoas main muscles. The needle was injected in-level, 3–4 cm side to the sagittal lumbar mid-line, and was progressive in a postero-anterior way among the L4 and L5 transverse procedures, till the tip of the needle was noticeable at the side boundary of the lumbar plexus. After the block, hemodynamics such as MAP, HR, and SaO2 continuously were monitored. After completion of the block, all cases were given 10 mg of metoclopramide hydrochloride for postoperative nausea and vomiting, then inhalational anesthetic was stopped, and reversal of residual neuromuscular blockade was done by using appropriate doses of neostigmine (0.05 mg/kg) and atropine (0.01 mg/kg). Time between block and extubation is the same in all patients. After full recovery, the cases were transferred to postoperative care unit and received postoperative care and hemodynamics as MAP, HR, and SaO2 were recorded at 1, 2, 4, 6, 8, 10, 12, 18, and 24 h and any increase or decrease in hemodynamics more than 20% of baseline values were managed. Hypotension was described as mean arterial pressure lessening greater than 20% mmHg. It was treated by injecting ephedrine 3–4 mg in bolus doses. Tachycardia was described as HRs greater than 100 beats/min and bradycardia described as HR less than 50 beats/min. It was managed with atropine 0.3 mg intravenous in bolus dosage.

VAS [9] at 1, 2, 4, 6, 8, 10, 12, 18, and 24 h. If VAS is more than or equal to 4, analgesics in the form of Ketolac 10 mg of intravenous was given with a maximum dosage of 90 mg daily. Time of the first analgesic request was recorded. If the analgesia was not adequate (VAS ≥4 for 20 min after Ketolac injection), intravenous Tramadol at 25 mg was given and total analgesic requirements of Ketolac and Tramadol were recorded.

Motor blockade was evaluated via adapted Bromage scale [10]: 0=no motor block. 1=inability to elevate the stretched leg, can move knees and feet. 2=disability to elevate the stretched leg or move the knee but able to move the feet. 3=complete motor block of the limb.

Motor blockade was assessed at 1, 2, 4, 6, 8, 10, 12, 18, and 24 h after the operation.

The case’s level of sedation was assessed using a five-point scale [11]: 0=alert and extensively awake, 1=arousable to verbal command, 2=arousable with gentle tactile stimulations, 3=arousable with vigorous shake, and 4=unarousable

Sedation scores were documented after the operation at 1, 2, 4, 6, 8, 10, 18, and 24 h.

Recovery score on discharge from postoperative anesthetic care unit was documented, discharge criteria were recorded as awake patient not complaining of any respiratory problem or pain also, hemodynamically stable and he can ambulate easily, and the occurrence of any side effects was recorded as hypotension, bradycardia, tachycardia, dry mouth, headache, anxiety, respiratory depression, and nausea and vomiting were treated with 4 mg of Ondansetron.

Statistical analysis

Findings of the current work have been statistically analyzed via SPSS 25 (IBM, USA). Data have been introduced as median (interquartile range) or numbers and percentages. The comparing among two groups with qualitative data was performed via χ2 testing and/or Fisher exact testing has been utilized instead of χ2 testing when the expected count in any cell was revealed to be less than 5. Paired-samples t test for parametric quantitative data amid every time with preoperative within each group. Kruskal–Wallis testing for nonparametric quantitative data amid the three groups trailed by Mann–Whitney testing among every two groups. Wilcoxon signed-rank testing for nonparametric quantitative data among every time with preoperative within every group. One-way analysis of variance testing for parametric quantitative data amid the three groups trailed by post-hoc Tukey’s analysis among every two groups. P value less than 0.05 is significant.

Sample-size calculation

Previous to the study starting, the number of cases needed in every group was calculated, thereafter, power calculations rendering to data attained from previous studies [11],[12]. In these studies, the mean time to the first analgesic request using bupivacaine was 642±384, when using DEX was 870.6±149.4, and when using magnesium was 788.5±435.99. A sample size of 25 cases in every group was calculated to deliver 80% power for one-way analysis of variance testing at the level of 0.05 significance via G Power 3.1 9.2 package.


  Results Top


Case features are presented in [Table 1]. The three groups were comparable regarding age, sex, weight, height, ASA classification, and surgical time.
Table 1 Case characteristic

Click here to view


Intragroup comparison recorded significant decline in mean HR in the three groups in comparison with the basal values at all-time intervals of recordings. In comparing the three studied groups, a significant change was recorded among group BD and BM after block P value less than 0.001, after extubation and 1, 6, 8, 10, 12, 18, and 24 h postoperatively with higher readings in group BM. Also, in comparing groups BD and B, a significant difference was recorded after block, after extubation, and 1, 8, 12, 18, and 24 h postoperatively with higher readings in group B P value less than 0.001. However, a nonsignificant change was recorded in HR in comparing groups BM and B in all-time intervals of recordings ([Table 2]).
Table 2 Variations in the mean heart rate (beat/min) in the study groups

Click here to view


[Table 3] illustrates the changes in MAP. Intragroup comparison recorded a significant decrease in MAP in comparison with the basal values at all-time intervals in three studied groups, P value less than 0.001. A significant change was recorded at 2 and 24 h postoperative in comparing groups BD and BM with higher readings that were recorded in group BM. But in comparing groups BD and B, a significant change was recorded at 2 and 24 h postoperative with higher readings that were recorded in group B. A nonsignificant change was recorded among BM and B groups in all-time intervals of recordings.
Table 3 Changes in the mean arterial blood pressure (mmHg) in the study groups

Click here to view


[Table 4] summarizes the changes in visual analog pain score (VAPs). Intragroup comparison recorded a significant increase in VAPs in all-time intervals of recordings in the three groups when compared with VAPs at 1 h postoperatively (baseline), P value less than 0.001. In comparing groups B and BD, a significantly lower VAP was recorded in group BD at time 1, 2, 4, 6, 8, 12, and18 h, P value less than 0.001. While it was significantly high in group B at time of 10 and 18 h postoperatively, was treated as listed in the protocol of the work with following reduction in VAS scores. About 8 h postoperatively, the VAS scores started to rise once more and became significantly high in B group (P<0.001), so a second dosage of rescue analgesia was given with following reduction in VAS scores. In comparing group B with group BM, a significantly lower VAP was recorded in group BM almost all-time intervals 1, 2, 4, 6, 8, 12, and 18 h, P value less than 0.001, but it becomes significantly high in group BM only at time of 12 h. Postoperative VAS was lower in MgSO4 and DEX groups than that in controls. At 12-h postoperative, the VAS was significantly lower in DEX group than MgSO4 group (P=0.005). It revealed that addition of these delivers a more extended period of analgesia to the case as compared with the controls. The superior impact was to DEX and then MgSO4 follows.
Table 4 Postoperative visual analog pain score

Click here to view


When comparing time of the first analgesic request between the three studied groups, we found that it was significantly longer in group BD (11.9±1 h) and group BM (10.6±0.7 h) when compared with group B (8.7±0.6 h) with significant change among the study groups as shown in [Table 5]. The DEX group experienced the prolonged pain-free period as compared with BM group and B group. These findings were signs that DEX and MgSO4 provide more satisfactory postoperative analgesia in comparison with bupivacaine alone ([Table 5]).
Table 5 Analgesic requirement and time to first analgesic request)

Click here to view


There was a significant change recorded when matching Ketolac requirement between the studied groups as significantly lower Ketolac doses were recorded in group BD than group BM and group B as shown in [Table 7]. In group BD, Ketolac was not needed in 21 (84%) cases, but was administered once in four (16%) cases. But in group B, Ketolac was administered twice in 22 (88%) cases, three (12%) cases receive three doses. Also, in comparing group B and BM, the median value of Ketolac requirement was statistically significantly lower in group BM (30 mg) than group B (60 mg) at which in group BM, nine (36%) cases did not need analgesia at all but was administered once in 14 (56%) cases, twice in two (8%) cases, also, a significant difference was recorded in comparing BD and BM groups.

[Table 6] shows that there was a nonsignificant change in 24-h opioid consumptions between cases in the three studied groups. Only in group B, Tramadol was administered once in three (12%) cases.
Table 6 Postoperative recovery score and time of discharge from anesthetic care unit

Click here to view


A nonsignificant change was detected in recovery score at the postoperative period from postanesthetic care unit and at the time of discharge in-between the three groups.

Adding of DEX as an adjuvant to bupivacaine in group BD allows earlier progression in Bromage score and also maintained through the study for a prolonged period compared with MgSO4 in group BM and by the application of bupivacaine alone in group B. Motor-block period as well exhibited a significant rise in the BD group in comparison with the other two groups (P<0.001). The period was significantly extended in the group BM than group B ([Table 7]). Return of the motor power to Bromage 0 was earlier in B group (6 h) than in BM group (8 h) and in BD group (10 h).
Table 7 Comparison of Bromage score among groups

Click here to view


A high significant change among the three groups’, P value less than 0.00 of the work regarding sedation scores is presented in [Table 8] and [Table 9]. It was revealed that at the first 1 h of the work, the median value of sedation scores was the highest between group BD. Also, it was revealed that from the second-hour postoperatively, there were no significant change among the three groups (P>0.05). The elevated sedation scores revealed in group BD may be assigned to the DEX managed in lumbar plexus block (LPB). The sedation was not that high due to the use of a small dose. Also, no respiratory depression was observed with 1 µg/kg DEX. No case practiced airway compromise or need airway aid owing to sedation.
Table 8 Comparison of intraoperative sedation score BD group

Click here to view
Table 9 Comparison of intraoperative sedation score among groups

Click here to view


There were no records of any complications relating to the technique as shown in [Table 10]. No side effects of local anesthetics happened throughout the first day postoperatively in the three groups.
Table 10 Comparison of intraoperative and postoperative complications among groups

Click here to view



  Discussion Top


Our prospective randomized double-blinded clinical trial was in a subset of cases subjected to elective lower-abdomen operations under general anesthesia. The cases were arbitrarily allocated into three groups to be treated by LBP using 0.5% bupivacaine only (control B) or combined with 1 μg/kg DEX (BD group) or 150 mg of MgSO4 (BM group) through shamrock LPB technique aiming to evaluate the efficacy of the technique and match the impact of adding of DEX or MgSO4 as an adjuvant. The basal and postoperative hemodynamics, postoperative VAS of pain, time to the first need of analgesia, total amount of analgesia given postoperatively, and any adverse effects were recorded. The three parallel groups were the same as regards the age, sex, weight, height, ASA classification, and surgical time. The results of the current research not only confirmed the safety and analgesic benefit of LPB block using bupivacaine but also revealed that adding MgSO4 or DEX to bupivacaine delayed the time of the first analgesic request and decreased the total amount of postoperative analgesics in comparison with bupivacaine alone and DEX was superior over MgSO4 in achieving these advantages.

The study is conducted in accordance with Elyazed and Mogahed [13] who compared the influence of MgSO4 and DEX as an adjuvant to ropivacaine for infraclavicular brachial plexus block (BPB) in 105 adult cases listed for surgical operation in upper-limb surgeries.

They concluded that MgSO4 or DEX is a beneficial adjuvant to ropivacaine for infraclavicular BPB in extending the period of analgesia. DEX provided earlier onset and extended period of SB as well as MB and extended period of analgesia with smaller consumptions of postoperative rescue analgesia, but, it exhibited an elevated occurrence of intraoperative hypotension and bradycardia than MgSO4.

Also, Singh et al. [14] investigated the effects of addition of MgSO4 125 mg, 250 mg, or 1 μg/kg DEX to 20 ml of 0.75% ropivacaine for supraclavicular nerve block. They found that the period of analgesia was significantly extended, the onset of sensory and motor blockade was shortened, and analgesic requirement was reduced without any significant side effects. The intensity of potentiation was higher with DEX than MgSO4. The superior influence was to DEX and then MgSO4.

In our study, pain scores were significantly lesser in the study groups for 12 and 18 h in BM and BD, respectively, also, there was a significant decrease at 2, 4, 6, 8, and 12 h in BD group versus BM group postoperatively and also both study groups demonstrated a significantly lower pain score than the control group for the first 18 h.

The study is conducted in accordance with Elbeialy [15] who added DEX to bupivacaine in US-guided trans-incisional quadratus lumborum block in eighty cases posted for elective open renal under general anesthesia. After completing the renal surgical operation and before skin closure, TiQLB was accomplished as the following: group DEX–bupivacaine (DB) (n=40), 30 ml of bupivacaine 0.25% plus 1 µg/kg DEX, and group bupivacaine (B) (n=40). Cases in the DB group have lower total morphine consumptions and lower VAS scores in comparison with cases in the B group (P<0.001).

The study is conducted in accordance with Anis et al. [16] who studied the effectiveness of US-guided LPB, in providing postoperative analgesia for cases experiencing hip surgical operation under overall anesthesia. They divided into three groups: group-A cases extubated. Group B, a mixed solution of 15 ml of bupivacaine 0.5% and 15 ml of normal saline 0.9% was injected via lumbar-plexus block method. Group C, 2.5 μg/ml clonidine was supplemented to bupivacaine. They revealed that back lumbar-plexus block was an effective and good postoperative analgesic maneuver. In distinction to group-A cases, VAS was low than 5 cm till sixth hour postoperatively in group-B cases and till the 12th hour in group C with high significant change in postoperative opioid use (P<0.001).

Elyazed and Mogahed [13] reported that postoperative VAS was lesser in MgSO4 and DEX groups than that in ropivacaine group. At 12-h postoperative, the VAS was still lower in DEX group than MgSO4 group (P=0.005).

On the other hand, Umalkar and Londhe [17] concluded that adding MgSO4 to bupivacaine in USG bilateral TAP block does not extend the period of postoperative analgesia after cesarean sections under spinal block utilizing either 25 ml of 0.25% bupivacaine and 75 mg of MgSO4 or 25 ml of 0.25% bupivacaine and 0.3 ml of normal saline on each side.

The analgesic properties of DEX on peripheral nerves (PNs) can be explained by the mechanism of α2-adrenergic receptor agonists that is multifactorial. Superficially, α2-adrenergic receptor agonists make analgesia by dropping the releases of norepinephrine and making α2-adrenergic receptor nondependent inhibitory influences on nerve-fiber action potential. Centrally, α2-adrenergic receptor agonists make analgesia by the inhibiting substance P releases in the nociceptive pathway at the level of dorsal root neuron and by activating of α2-adrenergic receptor in the locus coeruleus [18].

In the current study, the period to the first analgesic request was significantly extended in BD group (11.9±1 h) than BM group (10.6±0.7 h) and the studied groups were significantly longer than the control group (8.7±0.6 h).

The study is conducted in accordance with Elbeialy [15] as time to the first analgesic requirement was prolonged in cases in the DB group (18.6±2.4 h) in comparison with cases in the B group (7.3±1.1 h).

Also, the study conducted with Hussain et al. [19] who studied 50 cases listed for elective total abdomen hysterectomy underneath general anesthesia that has been randomized in a double-blinded model to group B received total anesthesia with TAP block made before extubating 20 ml of 0.25% bupivacaine with 2 ml of ordinary saline on every side and group BD that received general anesthesia with TAP block achieved before extubating 20 ml of 0.25% bupivacaine with DEX 0.5 μg/kg (in a volume of 2 ml) on every side, revealed that the time for the first dosage of analgesia for groups B and BD was 302.92±24.01 and 419.28±31.97 min. The mean of the entire consumptions of opioids on the first day postoperatively for groups B and BD was 14.20±2.36 and 10.40±1.38 mg, respectively.

The study is conducted in accordance with Mostafa et al. [20] who studied 90 parturients that were divided into three groups. They concluded that intrathecal DEX is better to intrathecal MgSO4 throughout cesarean sections.

Similar to our results, according to Elyazed and Mogahed [13], the mean period of analgesia with ropivacaine was 403.26±53.48 min, with MgSO4 598.71±51.54 min, and with DEX 684.14±51.57 min (P=0.000). DEX group provided the longer period of analgesia in comparison with ropivacaine group and MgSO4 group.

Our results detected that Ketolac consumed postoperatively in median values in group BD was significantly lesser than group BM (30) and both study groups were significantly low than controls (60) on the first day.

In the same context, Mostafa et al. [20] recorded that frequency of supplemental analgesia significantly varied with 100% of cases requesting second-dosage analgesia (1 g of paracetamol intravenous) in group C (n=30) versus 6.7% in group D (n=2) and 13.3% in group M (n=4).

Also, Elyazed and Mogahed [13] reported that use of postoperative rescue analgesia was significantly lower in MgSO4 (35.71±38.02) and DEX groups (16.71±31.20) than ropivacaine group (73.14±15.95).

In the present work, motor block was statistically significantly raised in the BD group in comparison with the other two groups (P<0.001). The period was significantly extended in the group BM in comparison with group B.

The study is conducted in accordance with Madavi et al. [21] who studied that 60 cases were separated into two groups of 30 cases for inguinal herniorrhaphy in para vertebral block (PVB).

The period of motor block was significantly extended in DEX group (498.03±22.94 min) than bupivacaine group (267.17±9.67 min).

Also, Hassan and Abdelkareem [22], who compared 200 mg of MgSO4 versus 100 µg of DEX as adjuvants to levobupivacaine in USG supraclavicular block in case of undergoing upper-limb surgeries, found that both MgSO4 (motor-block duration 8.50±2.33 h) and DEX (motor period 9.80±1.933 h) increased the duration of motor block, but using DEX is superior than MgSO4.

This is explained as addition of DEX may cause contraction of perineural vessel by coupling with alpha-2B adrenergic receptor, decrease the absorptions of local anesthetics, and then extend the period of block [18].

On the other hand, the study done by Bi et al. [23] concluded that 3 μg of intrathecal DEX as an additive to ropivacaine in spinal anesthesia for cesarean sections improved postoperative analgesia and did not affect the period of motor block.

Analgesic impacts of MgSO4 on the PN can be clarified by the NMDA-receptor antagonist influence that leads to preventions of central sensitization from peripheral nociceptive stimulations, in addition to magnesium that decreases the releases of acetylcholine via the competitive block of the calcium entry in presynaptic finishes. Additional probable action mechanism of MgSO4 on the PN is the surface-charge concept. The modulation of the external Mg concentrations bathing a nerve bundle may improve the PN block made by LA, as well as the high concentrations of Mg attracted by the negative charge of the outer-membrane superficial influenced Na+ channel gating and can lead to hyperpolarization that causes inhibitions of nerve conductions [24].

The study is conducted in accordance with Deshpande and Patil [25] and Nahida et al. [26] that addition of 150 mg of MgSO4 to ropivacaine for USG-guided PN block in upper-limb surgeries has longer duration of anesthesia and postoperative analgesia. This caused a significant decrease in the consumptions of systemic analgesics postoperatively.

In this research, we utilized a relatively low dose of MgSO4 but it was sufficient to produce significant reduction in VAPs and the postoperative analgesic consumption without any neurological complications after comparing different studies that use magnesium in different doses as an adjuvant to local anesthetics as Verma et al. [27] utilized two doses of 125 mg and 250 mg of MgSO4 as an adjuvant to bupivacaine for supraclavicular BPB in 100 cases experiencing upper-limb operations. They settled that the action of MgSO4 added as an adjuvant to bupivacaine is dosage-responsive manner and extends the period of analgesia and aids in dropping the usage of analgesic medications in the postoperative interval with no adverse effect. The elevated doses (250 mg) of MgSO4 were superior in comparison with 125 mg.Also, with Jebali et al. [28] where 50 cases scheduled for lower-limb surgical operation concluded that adding of 15% (450 mg) with 15 ml of 2% lidocaine is efficient and safe in prehospital femoral nerve block (FNB).

In our study, the first 1 h of the investigation, the median value of sedation scores was the highest between group BD. Also, it was revealed that starting from the second hour postoperatively, there were nonsignificant differences among the three groups (P>0.05). Also, Mohamed and Gad [29] added 100 μg of DEX to bupivacaine for brachial plexus block for upper-limb surgeries and revealed significant higher sedation scores in the DEX group from 30 to 360 min in comparison with controls. This is because the sedative influence of DEX is locus coeruleus and is intermediated by hyperpolarization of noradrenergic neurons, thus inhibiting noradrenaline releases, and inhibits activity in descendant medullospinal noradrenergic pathways [18].

Analogous findings were stated by Elbeialy [15] and Mostafa et al. [19]. However, Ding et al. [30] and Santosh and Mehandale [31] noticed that DEX did not have any sedation.

In our study, preoperative values of MAP and HR were comparable among the three groups. Postoperative MAP and HR significantly decreased in the DEX group as compared with its preoperative value and with the other two studied groups. Also, six cases had experienced bradycardia that was treated with atropine.

Similar to our results, Elyazed and Mogahed [14] found that three cases in group III had higher incidences of bradycardia.

Similar results were reported by Hashim and Hassan [32] and Kumar and Sahoo [33].

This reduction in HR in the DEX group is because of baroreceptor reflex and improved vagal activity that causes the stimulations of parasympathetic and inhibitions of sympathetic outflow [32].

However, Akhondzadeh et al. [11] added 1 μg/kg of DEX to lidocaine in supraclavicular block, which did not cause significant differences between the studied groups as regards HR and systolic and diastolic blood pressure.

No adverse effects had happened.

Our study has a few limitations:
  1. Performing LPB while the case is asleep. Performing LPB throughout wakefulness may deliver more security and simply evaluation of analgesia levels.
  2. Exclusion of morbid obese cases owing to the trouble of visualizations. Assessing the LPB influence for morbid obese cases can be significant in the upcoming event.
  3. The success rate of the block and extent of abdomen-wall sensory blockade were not evaluated, as the block was managed after general anesthesia.
  4. The use of other adjuvants to local anesthetics to rise the period of block.
  5. This work examined the effects of single-injection block, rather than continuous block.
  6. In the present work, the cases were limited to cases with age 21–65 years old, therefore, the appropriate doses of DEX for children that require further investigation.



  Conclusion Top


In conclusion, posterior lumbar-plexus block was an effective postoperative analgesic maneuver in cases experiencing lower abdominal operations. Using DEX 1 μg/kg or MgSO4 150 mg as an adjuvant to 0.5% bupivacaine for US-guided LPB in providing good analgesia is better and safe. DEX has a superior influence than MgSO4, but the frequency of postoperative hypotension and bradycardia was higher than MgSO4.

Recommendations

Based on our results of the current study

  1. We recommend future studies using a catheter for longer period of analgesia.
  2. We recommend further studies using different adjuvant medications added to LPB to assess efficacy.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Urigel S, Molter J. Transversus abdominis plane (TAP) blocks. American Association of Nurse Anesthetists journal (AANA) 2014. 82.  Back to cited text no. 1
    
2.
Klaastad Ø, Sauter AR, Dodgson MS. Brachial plexus block with or without ultrasound guidance. Curr Opin Anesthesiol 2009; 22:655–660.  Back to cited text no. 2
    
3.
Ertmer M, Klotz E, Birnbaum J. The concept of protective nerve stimulation for ultrasound guided nerve blocks. Med Hypotheses 2017; 107:72–73.  Back to cited text no. 3
    
4.
Woolf CJ. Central sensitization: implications for the diagnosis and treatment of pain. Pain 2011; 152:S2–S15.  Back to cited text no. 4
    
5.
Khairnar P, Agarwal M, Verma UC, Kumar R. Comparative efficacy of ropivacaine and levobupivacaine in combined femoral and lateral femoral cutaneous nerve block with adjuvant magnesium for post-operative analgesia. Indian J Anaesth 2016; 60:584.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Scott-Warren V, Sebastian J. Dexmedetomidine: its use in intensive care medicine and anaesthesia. BJA Educ 2016; 16:242–246.  Back to cited text no. 6
    
7.
Hu X, Li J, Zhou R, Wang Q, Xia F, Halaszynski T, Xu X. Dexmedetomidine added to local anesthetic mixture of lidocaine and ropivacaine enhances onset and prolongs duration of a popliteal approach to sciatic nerve blockade. Clin Ther 2017; 39:89–97.  Back to cited text no. 7
    
8.
Wewers ME, Lowe NK. A critical review of visual analogue scales in the measurement of clinical phenomena. Res Nurs Health 1990; 13:227–236.  Back to cited text no. 8
    
9.
Bromage PR. A comparison of the hydrochloride and carbon dioxide salts of lidocaine and prilocaine in epidural analgesia. Acta Anaesthesiol Scand 1965; 9:55–69.  Back to cited text no. 9
    
10.
Armstrong RL. The midpoint on a five-point Likert-type scale. Percept Mot Skills 1987; 64:359–362.  Back to cited text no. 10
    
11.
Akhondzadeh R, Rashidi M, Gousheh M, Olapour A, Baniahmad A. The influence of adding dexmedetomidine as an adjuvant to lidocaine in forearm fracture surgeries by supraclavicular block procedure under ultrasoundguided. Anesth Pain Med 2018; 8:4.  Back to cited text no. 11
    
12.
Srivastava U, Kumar A, Saxena S, Naz A, Goyal V, Mehrotra R. Lumbar plexus block for post-operative analgesia following hip surgical operation: A comparison of ‘3 in 1‘ and psoas compartment block. Indian J Anaesth 2007; 51:127.  Back to cited text no. 12
    
13.
Elyazed MMA, Mogahed MM. Comparison of magnesium sulfate and dexmedetomidine as an adjuvant to 0.5% ropivacaine in infra-clavicular brachial plexus block. Anesth Essays Res 2018; 12:109.  Back to cited text no. 13
[PUBMED]  [Full text]  
14.
Singh S, Raman R, Singh GP, Singh V, Kumar S, Tewari V. Randomised control trial of dexmedetomidine and magnesium sulfate as an adjuvant to ropivacaine in supraclavicular brachial plexus block. Int J Contemp Med 2019; 7:39–44.  Back to cited text no. 14
    
15.
Elbeialy MA. Dexmedetomidine added to bupivacaine versus bupivacaine in transincisional ultrasound-guided quadratus lumborum block in open renal surgeries: a randomized trial. Pain Physician 2020; 23:271–281.  Back to cited text no. 15
    
16.
Anis S, Abd El Moaty N, Youssef A, Ramzy R, Hassan R. Lumbar plexus block as a method of post-operative analgesia after hip surgical operation. Egypt J Anaesth 2011;127–133.  Back to cited text no. 16
    
17.
Umalkar M, Londhe N. Evaluation of magnesium sulfate as an adjuvant to bupivacaine for post-operative analgesia in ultrasound-guided transversus abdominis plane block in cases scheduled for lower segment caesarean section under subarachnoid block-A prospective, randomized, double-blind study. Indian J Pain 2020; 34:189.  Back to cited text no. 17
  [Full text]  
18.
Wang C-G, Yang J-P, Hu C-Q, Ding Y-L. The effect of adding dexmedetomidine to ropivacaine for lumbar plexus and sciatic nerve block. Int J Clin Exp Med 2016; 9:14198–204.  Back to cited text no. 18
    
19.
Hussain A, Hussain A, Feroze R, Akram M, Saleem MA, Ali A. Comparison of bupivacaine and dexmedetomidine versus bupivacaine alone in transversus abdominis plane block for post-operative analgesia. J Rawalpindi Med Coll 2021; 25:112–116.  Back to cited text no. 19
    
20.
Mostafa MF, Herdan R, Fathy GM, Hassan ZEZ, Galal H, Talaat A et al. Intrathecal dexmedetomidine versus magnesium sulphate for post-operative analgesia and stress response after caesarean delivery; randomized controlled double‐blind study. Eur J Pain 2020; 24:182–191.  Back to cited text no. 20
    
21.
Madavi SK, Sen J, Sen B, Shinde S. Comparison of bupivacaine [0.5%) and bupivacaine [0.5%) with dexmedetomidine [1 microgram/kg) in paravertebral block for inguinal hernia repair. J Datta Meghe Inst Med Sci Univ 2020; 15:176.  Back to cited text no. 21
    
22.
Hassan AH, Abdelkareem AM. Comparative study between magnesium sulphate versus dexmedetomedine as additives to levobupivacine in ultra sonographic guided supraclavicular block in case undergoing forearm surgeries. Egypt J Hosp Med 2021; 83:1010–1016.  Back to cited text no. 22
    
23.
Bi YH, Wu JM, Zhang YZ, Zhang RQ. Influence of different doses of intrathecal dexmedetomidine as an adjuvant combined with hyperbaric ropivacaine in cases undergoing cesarean section. Front Pharmacol 2020; 11:342.  Back to cited text no. 23
    
24.
Al-Refaey K, Usama E, Al-Hefnawey E. Adding magnesium sulfate to bupivacaine in transversus abdominis plane block for laparoscopic cholecystectomy: A single blinded randomized controlled trial. Saudi JAnaesth 2016; 10:187.  Back to cited text no. 24
    
25.
Deshpande JP, Patil KN. Evaluation of magnesium as an adjuvant to ropivacaine-induced axillary brachial plexus block: a prospective, randomised, double-blind study. Indian J Anaesth 2020; 64:310.  Back to cited text no. 25
  [Full text]  
26.
Nahida Q, Wani SA, Rasool S, Saleem A, Wani N. Comparison of ropivacaine with magnesium sulphate and plain ropivacaine in ultrasound guided supraclavicular blocks for upper limb surgeries. Int J Contemp Med Res 2020; 7:I7–I10.  Back to cited text no. 26
    
27.
Verma V, Rana S, Chaudhary SK, Singh J, Verma RK, Sood S. A dose-finding randomised controlled trial of magnesium sulphate as an adjuvant in ultrasoundguided supraclavicular brachial plexus block. Indian J Anaesth 2017; 61:250–255.  Back to cited text no. 27
    
28.
Jebali C, Kahloul M, Hassine NI, Jaouadi MA, Ferhi F, Naija W et al. Magnesium sulfate as adjuvant in prehospital femoral nerve block for a case with diaphysial femoral fracture: a randomized controlled trial. Pain Res Manage 2018; 2018:2926404.  Back to cited text no. 28
    
29.
Mohamed H, Gad G. Bupivacaine-dexmedetomidine versus bupivacaine-nalbuphine in ultrasound-guided supraclavicular brachial plexus block: a prospective, randomized, double-blind study. Ain-Shams J Anesthesiol 2021; 13:1–7.  Back to cited text no. 29
    
30.
Ding W, Li W, Zeng X, Li J, Jiang J, Guo C et al. Influence of adding dexmedetomidine to ropivacaine on ultrasound-guided dual transversus abdominis plane block after gastrectomy. J Gastrointest Surg Oper 2017; 21:936–946.  Back to cited text no. 30
    
31.
Santosh B, Mehandale SG. Does dexmedetomidine improve analgesia of superficial cervical plexus block for thyroid surgical operation?. Indian J Anaesth 2016; 60:34.  Back to cited text no. 31
[PUBMED]  [Full text]  
32.
Hashim RM, Hassan RM. The efficacy of adjuvants to bupivacaine in ultrasound-guided supraclavicular block: a comparative study between dexmedetomidine, ketamine, and fentanyl. Ain-Shams J Anesthesiol 2019; 11:1–8.  Back to cited text no. 32
    
33.
Kumar A, Sahoo A. Comparison of magnesium sulfate and dexmedetomidine as an adjuvant to 0.5% bupivacaine in supraclavicular brachial plexus block. 2020  Back to cited text no. 33
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
   Abstract
  Introduction
  Aim
  Patients and methods
  Results
  Discussion
  Conclusion
   References
   Article Tables

 Article Access Statistics
    Viewed198    
    Printed4    
    Emailed0    
    PDF Downloaded43    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]