|Year : 2019 | Volume
| Issue : 2 | Page : 164-175
Fentanyl versus dexmedetomidine as adjuvants to lignocaine in intravenous regional anesthesia
Department of Anesthesiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||24-Nov-2017|
|Date of Acceptance||29-Nov-2018|
|Date of Web Publication||12-Jun-2019|
Source of Support: None, Conflict of Interest: None
Background and objectives Intravenous regional anesthesia (IVRA) is a safe, simple, and inexpensive technique compared with general anesthesia for upper and lower limb surgeries. It also provides a bloodless area during surgery. Various adjuvants have tried to fasten the onset, prolong the duration of the block, and to increase postoperative analgesia. We compared fentanyl and dexmedetomidine as adjuvants to lignocaine for IVRA for upper limb surgeries.
Patients and methods After the approval of the ethics committee of the institution, 64 patients of both sexes who were scheduled for optional hand or forearm surgery were divided into two groups (32 patients in each group); 32 patients received a 20 ml lignocaine 1%+1 µg/kg fentanyl in 5 ml supplemented with normal saline 0.9% (LF group) and 32 patients received 20 ml of lignocaine 1%+1 µg/kg dexmedetomidine in 5 ml supplemented with normal saline 0.9% (LD group). The following parameters were observed: blood dynamics, the time of the start of sensory and motor blockade, the need for analgesia during the operation, the time for first postoperative analgesia, and side effects between groups.
Results There was a significant reduction in sensory and motor block onset in the fentanyl group compared with the dexmedetomidine group (P<0.0001). The time to first postoperative analgesia was prolonged in the LD group as compared with group LF (P<0.001). The results showed no statistically significant differences between the two groups (P>0.05) in relation to the need for analgesia during the procedure. The results showed that patients in the LF group were more satisfied than the LD group (P<0.05). The results were also higher in the LD group compared with group LF (P<0.001) as regards the sedation score. The results showed no statistically significant differences in heart rate, blood pressure, and oxygen saturation between the two groups (P>0.05).
Conclusion We conclude that adding 1 μg/kg dexmedetomidine or 1 μg/kg fentanyl to lignocaine for IVRA improves the quality of anesthesia and perioperative analgesia without causing complications. We found that fentanyl reduces the time for onset of block and provided better patient satisfaction than dexmedetomidine although it scored the highest sedation score.
Keywords: adjuvants, dexmedetomidine, fentanyl, intravenous, lignocaine, regional anesthesia
|How to cite this article:|
Mahrose R. Fentanyl versus dexmedetomidine as adjuvants to lignocaine in intravenous regional anesthesia. Res Opin Anesth Intensive Care 2019;6:164-75
|How to cite this URL:|
Mahrose R. Fentanyl versus dexmedetomidine as adjuvants to lignocaine in intravenous regional anesthesia. Res Opin Anesth Intensive Care [serial online] 2019 [cited 2019 Oct 14];6:164-75. Available from: http://www.roaic.eg.net/text.asp?2019/6/2/164/260137
| Introduction|| |
Intravenous regional anesthesia (IVRA) was first described in 1908 for hand and forearm anesthesia. Procaine was the oldest injected drug into the isolated vascular space. This process became famous in 1960, when Holmes used xylocaine. The traditional local anesthetic (LA) for surgical operations in North America is xylocaine and prilocaine is widely used in Europe .
IVRA is easy to administer, reliable, and is cost effective. It is ideal for short operations on limbs that are performed on an outpatient basis. Disadvantages include concerns about the toxicity of LA, slow onset, weak muscular relaxation, tourniquet pain, and minimal postoperative pain relief .
IVRA’s ideal solution should have the following characteristics: quick onset, low dose of LA, low tourniquet pain, and prolonged postdeflation analgesia. At present, this can only be achieved by adding adjuncts to LA. Several adjuvants, including narcotic drugs, anti-inflammatory drugs (NSAIDs), muscle relaxants, α2-stimulants, and neostigmine have been used .
Much research has been done on the appropriate additives to reduce the dose of anesthetic and to provide improved tourniquet tolerance, improve muscular relaxation, and control pain for a long time after surgery. Research suggests that some adjuvants may provide some benefits (e.g. ketorolac, clonidine, meperidine, and muscle relaxants) .
Fentanyl is a powerful opioid that can be added to a LA during IVRA to increase the rate of success of the blockade and extend postoperative analgesia .
Dexmedetomidine is an α2-adrenergic agonist and produces sedation, hypnosis, analgesia, and anxiolysis by acting on α2-receptors in the locus ceruleus in the pons .
The aim of this study is to compare the onset and duration of sensory blockade with the addition of fentanyl and dexmedetomidine to lignocaine in intravenous anesthesia and also to compare the hemodynamic effects, postoperative analgesia, and side effects of these two drugs after the release of the tourniquet.
| Patients and methods|| |
This study was conducted in Ain Shams University Hospitals during a period of 6 months from November 2016 to April 2017 on 64 patients of both sexes scheduled for elective hand or forearm surgery.
After obtaining approval from the Research Ethics Committee of Ain Shams University, informed patient consent was obtained from Ain Shams University Hospitals; before the procedure, the patients were included with the following criteria.
- Age 20–70 years.
- American Society of Anesthesiologists physical status (ASA) I, II, and III patients.
- Sex: male and female.
- Patients scheduled for elective hand or forearm surgery.
- Operative duration more than an hour.
- Age less than 20 years or more than 70 years.
- ASA IV patients.
- Patients with a history of Reynaud’s or sickle cell anemia disease.
- Patients with neurological or psychiatric diseases.
- Patients known to be epileptic.
- Patients with a history of known hypersensitivity to any of the used drugs.
- Patient refusal.
Preoperative assessment includes history, physical examination, and routine investigations to achieve inclusion criteria and excludes those with exclusion criteria and informed consent.
Two venous cannulas were inserted into both arms of all patients, one in the operative side and the other in the opposite hand for crystalloid infusion. The operative arm was elevated for 2 min and using an Esmarch bandage, the venous capacitance of the arm was emptied. Then a double pneumatic tourniquet was applied. The selection of tourniquets is closely related to the diameter and length of the arm. The length is 40% bigger than the diameter of the arm and the width is 5–6 cm. The proximal tourniquet was adjusted to a pressure of 100 mmHg above the systolic pressure of the patient; 5 min after injection of LA the distal tourniquet was inflated and the proximal one was deflated. Circulatory isolation of the arm was confirmed by inspection, lack of radial pulse, and failure of pulse oximetry tracing of the ipsilateral index finger.
The patients were randomly assigned into two groups (32 patients each using the closed envelope method).
Group LF (32 patients) received lignocaine+fentanyl
Patients received 20 ml of lignocaine 1%+1 μg/kg fentanyl [in 5 ml added to normal saline (0.9%)].
Group LD (32 patients) received lignocaine+ dexmedetomidine
Patients received 20 ml of lignocaine 1%+1 μg/kg dexmedetomidine [in 5 ml added to normal saline (0.9%)].
Deflation time was at least after 30 min of drug injection; it was done in a gradual manner with close monitoring and observation.
Mean arterial blood pressure, peripheral oxygen saturation, heart rate, as baseline after injection of LA, before tourniquet release 1 h after tourniquet releases.
The start of sensory block (time from injection to loss of pain sensation) was determined by the pin prick test distal to the tourniquet at 20 s interval and onset of motor block was recorded at 1-min intervals when the patient could not produce any movement of the fingers.
The need for intraoperative analgesia was recorded. After the release of the tourniquet signs of LA toxicity and degree of sedation were measured by the Ramsay sedation score [Table 1].
At the end of the operation, we evaluate the satisfaction score of the patient for the anesthetic technique according to the following numeric scale:
3=good (no complaint from the patient).
2=moderate (minor complaint with no need for supplemental analgesics).
1=poor (complaint which required supplemental analgesics), duration of surgery, and time for first analgesia needed by the patient were measured.
Time to first analgesic demand, pain score, and sedation score [Table 2] (Ramsay sedation score) were compared.
Microsoft access was used for statistical analysis, interpretation, dissemination of the results, and data entry; then analysis was done using the Statistical Package for the Social Sciences for Windows (version 13.0; SPSS Inc., Chicago, Illinois, USA).
Numerical data were presented as mean (SD) while categorical data were presented as number of cases (%).
Variables with normal distribution were analyzed using the Student’s t test while non-normally distributed variables were analyzed using the Mann–Whitney rank sum test. Categorical data were analyzed using Fisher’s exact test.
Hemodynamic responses were measured by repeated analysis of variance test to detect differences in the same patient over more than two measurements.
A P value of less than 0.05 was considered statistically significant while a P value of more than 0.05 was statistically nonsignificant and a P value of less than 0.001 was considered highly statistically significant.
Sample size estimation
To show a difference of need of intraoperative analgesia between the two groups with a P value of less than 0.05 and power 81%, we needed at least 32 patients per group.
| Results|| |
This study concluded 64 patients who were divided into two groups: each group comprising 32 patients, ages ranged from 20 to 70 years, ASA (I/II), and both sex. So regarding age, sex, ASA, and duration of surgery, there were no significant statistical differences between the two groups (P>0.05) as shown in [Table 3] and [Figure 1] and [Figure 2].
|Table 3 Comparison between the two different groups as regards age (in years), sex, American Society of Anesthesiologists, and duration of surgery (min)|
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|Figure 2 Comparison between the two groups regarding ASA status. ASA, American Society of Anesthesiologists.|
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Hemodynamics and vital data
Heart rate, mean arterial blood pressure, and oxygen saturation were monitored before induction (baseline), after injection of LA, before the release of the tourniquet, and after 1 h. The values were compared between the two groups.
The results showed that there were no significant statistical differences between the two groups as regards heart rate, blood pressure, and oxygen saturation (P>0.05) as shown in [Table 4],[Table 5],[Table 6] and [Figure 3],[Figure 4],[Figure 5].
|Table 4 Comparison between the two groups regarding mean arterial blood pressure (mmHg)|
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|Table 5 Comparison between the two groups regarding heart rate (beat/min)|
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|Figure 3 Comparison between two groups regarding onset of MABP. MABP, mean arterial blood pressure.|
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|Figure 4 Comparison between two groups regarding onset of HR. HR, heart rate.|
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|Figure 5 Comparison between two groups regarding onset of SPO2. SpO2, oxygen saturation.|
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Onset of sensory, motor block, and need of intraoperative analgesia
Onset of sensory and motor block
The onset of sensory block (time from injection to loss of pain sensation) were determined by the pin prick method distal to the tourniquet at 20 s interval and the onset of motor block was recorded at 1-min interval when the patient could not produce any movement of the fingers. In group LF, the onset of sensory block occurred after 20–40 s and motor block after 10–15 min while in group LD the onset of sensory block occurred after 50–60 s and motor block after 20–25 min.
The results showed that the onset of sensory and motor blockades was faster in group LF as compared with group LD (P<0.0001) which is a highly significant statistical value.
Need of intraoperative analgesia
The results showed no statistically significant differences between the two groups (P>0.05) ([Table 7], [Figure 6] and [Figure 7]).
|Table 7 Comparison between two groups regarding onset of sensory, motor block and need of intraoperative analgesia|
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|Figure 6 Comparison between two groups regarding onset of sensory block.|
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Sedation score, postoperative pain score, time to first postoperative analgesia, and satisfaction score
Number of patients with sedation score 1 were 10, score 2 were 10, and score 3 were 12 in group LF while the number of patients with sedation score 1 was 4, score 3 was 14, and score 4 was 14. The results were higher in group LD than in group LF (P<0.001).
The number of patients with satisfaction score 3 was 20, score 2 was eight, and score 1 was four in group LF while the number of patients with satisfaction score 3 was 10, score 2 was six, and score 1 was 16 in group LD. The results showed that the patients in group LF were more satisfied than those in group LD (P<0.05).
Postoperative pain score
The number of patients with pain score 0 (no pain) was 16, scores 1–3 (mild pain) was 14, and scores 7–10 (severe pain) was two in group LF, while the number of patients with pain score 0 was 18, scores 1–3 was 10, and scores 7–10 was four in group LD. The results showed that there were no statistically significant differences between the two groups (P>0.05) as regards the postoperative pain score.
First time for postoperative analgesia
The number of patients who need postoperative analgesia was 20 after 30 min and 12 patients after 45 min in group LF, while in group LD 16 patients needed analgesia after 15 min and 16 patients after 25 min. The results showed that the time to first postoperative analgesia were prolonged in group LD as compared with group LF (P<0.001) ([Table 8] and [Figure 8],[Figure 9],[Figure 10],[Figure 11]).
|Table 8 Comparison between the two groups regarding satisfaction score, time to first postoperative analgesia, pain score, and sedation score|
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|Figure 8 Comparison between the two studied groups regarding satisfaction score.|
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|Figure 9 Comparison between the two studied groups regarding pain score.|
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|Figure 10 Comparison between the two studied groups regarding sedation score.|
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|Figure 11 Comparison between the two studied groups regarding time to first postoperative analgesia.|
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| Discussion|| |
Bier’s block is easy to provide, reliable, cost-effective and is ideal for short upper limb surgery and avoid the risk of general anesthesia in patients who suffer from severe systemic disease .
Bier’s block side effects include LA toxicity, slow onset, weak muscle relaxation, tourniquet pain, and minimal pain relief after surgery. The ideal drug for Bier’s block has: a faster onset, a lower dose of LA, decreased tourniquet pain, and delayed postoperative analgesia. There is no LA that meets these characteristics and thus we need adjuvant to LA .
As mentioned above, IVRA sometimes does not provide effective anesthesia and postoperative analgesia. To reduce the dose of anesthesia, improve tolerance, and the quality of IVRA with better muscle relaxation, as well as prolong the duration of postoperative sedation, adding various drugs for LA found with controversial results such as tramadol, clonidine, neostigmine, NSAIDs was found effective.
Gobeaux et al.  added 100 μg of fentanyl to adrenalized lignocaine for brachial plexus block and reported increasing levels of sensory and motor blockade.
Geze and Hulya  found that tramadol has a better block than fentanyl in the axillary plexus blockade in terms of quality.
Pitakanen et al.  in the study of the effect of adding fentanyl to prilocaine for IVRA was reported to be of no great benefit for the postoperative duration of analgesia.
In a study Sztark and colleagues evaluated the effectiveness of the addition of fentanyl and pancuronium to reduce the concentration of lignocaine used for IVRA. Their main objective was to measure the effectiveness of adjuvants and successful regional anesthesia with a lower concentration of lignocaine. The researchers also found that the time for first postoperative analgesia was not significantly different between the two groups .
Usage of α2 agonist in the treatment of pain is attractive due to the potentiation that occurs through central and peripheral sites, as well as sedative, analgesic, perioperative sympatholytic, and cardiovascular stability effects in addition to their general anesthetic benefits and their ability to lengthen LA-induced analgesia when used in regional blocks. Two drugs that are part of α2 adrenergic receptor agonists, clonidine and dexmedetomidine, have been focused as adjuvants for IVRA in recent clinical trials .
Gentili et al.  and Lurie et al.  both reported that the addition of clonidine to IVRA greatly increased tourniquet tolerance.
Dexmedetomidine is a powerful α2-adrenoceptor agonist with an eight-fold higher affinity for the receptors of clonidine. Dexmedetomidine produces anesthesia, anxiolysis, and analgesia. Dexmedetomidine is a more selective α2-adrenoceptor agonist compared with clonidine, which can allow its use in relatively high doses of anesthesia and analgesia without undesirable vascular effects of activated α1 receptors. In addition, dexmedetomidine is a shorter-acting drug than clonidine and has a reversal drug for its sedative effect. These properties make dexmedetomidine suitable for anesthesia and postoperative analgesia: as a premedication, as an anesthetic adjunct to general and regional anesthesia, and as a postoperative sedative and analgesic .
Memis and colleagues studied the effects of adding dexmedetomidine (0.5 µg/kg) to 40 ml of 0.5% lignocaine during Bier’s block. They found a significant reduction in the time of sensory block in the dexmedetomidine group (4.4±2.1 min) compared with the control group (6.5±2.1 min), prolonged periods of sensory and motor blockage, increased tolerance for tourniquet, and improved anesthesia in the dexmedetomidine group. The first time for analgesic requirements was in the dexmedetomidine group. They concluded that dexmedetomidine, as adjunct to IVRA, effectively improves the onset of the block, prolonged duration of the block, and the need for postoperative analgesia. In our study, the sensory block time in the LD group (56±2.9 s) was shorter than the sensory block time in the dexmedetomidine group at the Memis and colleagues study. This can be explained by the fact that we used double the dose of dexmedetomidine, which they used .
Esmaoglu and colleagues investigated the effect of a higher dose of dexmedetomidine in 40 patients scheduled for optional hand surgery. IVRA was obtained using 3 mg/kg of diluted lignocaine with a saline solution to a total volume of 40 ml, either alone in the control group or +1 µg/kg dexmedetomidine in the dexmedetomidine group. There was no difference between the groups with respect to the onset of sensory (3.2±1.2 min) and motor blocks (4.5±0.8 min) and time of regression. The study showed a sensory onset in LD (56±2.9 s) and motor onset (23.4±17 min) which may be due to the use of higher concentrations of lignocaine. However, the anesthetic quality in the dexmedetomidine group was significantly better in reducing analgesic requirements intraoperatively and postoperatively .
Nasr and Waly compared the effect of lignocaine–dexmedetomidine versus lignocaine–tramadol on IVRA. All patients received 0.5% lignocaine (3 mg/kg) diluted with a total volume of 40 ml of isotonic saline solution, either alone or with 100 mg tramadol (T group) or 1 µg/kg dexmedetomidine (group D). Sensory as well as motor block onset times were significantly shorter in T groups and D (2.0±1.7 and 3.9±2.3 min) compared with 0.5% lignocaine (3 mg/kg) control group C (P<0.05). Still in our study the onset of sensory block was shorter because of the higher concentration of lignocaine in our study .
Gupta and colleagues compared the effect of adding different doses of dexmedetomidine to IVRA. The study included 60 patients divided into two groups. They received 40 ml of 0.5% lignocaine with either dexmedetomidine 0.5 µg/kg (group A) or dexmedetomidine 1 µg/kg (group B). The sensory onset was significantly shorter in group B (1.05±0.346 min). This result strongly correlates with our results, which showed a sensory block onset time in the LD group range (56±2.9 s) .
On the other hand, Nasr and Waly compared the effect of lignocaine–tramadol versus lignocaine–dexmedetomidine for IVRA. All patients received 0.5% lignocaine (3 mg/kg) diluted with a total of 40 ml of isotonic saline solution, either alone or with 100 mg tramadol (T group) or 1 µg/kg dexmedetomidine (group D). They reported statistically significant reductions in heart rate immediately after tourniquet deflation in the dexmedetomidine group, which could not be correlated with our results because we did not measure it directly after tourniquet release . In a more recent study, in 2014 Abdel-Ghaffar and colleagues studied 40 patients undergoing surgery of the hand or forearm under IVRA. It was randomly assigned to 3 mg/kg lignocaine (L group) or lignocaine 3 mg/kg plus 50 mg ketamine (group LK) diluted to 40 ml total with isotonic saline. It also did not make any significant changes in blood dynamics during the process in the ketamine group. This is consistent with our results, although ketamine has a circulatory effect (high blood pressure and arrhythmia) after the release of the tourniquet, but these effects do not appear when used as an aid to IVRA. This may be due to the fact that the tourniquet was not deflated before 30 min and tourniquet deflation was performed gradually at the end of surgery .
El-Tahawy and colleagues studied 60 patients scheduled for upper hand or forearm surgery. All patients were pretreated with 0.5 mg/kg oral midazolam and were divided into two groups. Group D received dexmedetomidine at a concentration of 0.5 µg/kg, diluted with saline solution to 20 ml, in addition to 20 ml of 1% lignocaine to a total volume of 40 ml, while the M group received 5 ml of 20% magnesium sulfate and 15 ml saline added to 20 ml of 1% lignocaine to reach a total volume of 40 ml. The authors also reported a significant reduction in heart rate levels and mean arterial blood pressure compared with the baseline values of the dexmedetomidine group, which differ from the results of this study, and this may be due to preoral medications .
| Conclusion|| |
We conclude that the addition of 1 μg/kg dexmedetomidine or 1 μg/kg fentanyl to lignocaine for IVRA improves quality of anesthesia and perioperative analgesia without causing complications. We found that fentanyl reduces the time for onset of block and provided better patient satisfaction than dexmedetomidine although it scored the highest sedation score.
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Conflicts of interest
There are no conflicts of interesting.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]