Efficacy of Tramadol or Dexamethasone as an Adjuvant to Levobupivacaine in Ultrasound-guided Supraclavicular Plexus Block for Upper Limb Surgery: A Randomized Double-blinded Controlled Study.

AIMS AND
OBJECTIVES: To evaluate the efficacy of tramadol or dexamethasone as an adjuvant to levobupivacaine in ultrasound-guided supraclavicular brachial plexus block in terms of onset time of complete sensory and motor blockade, duration of motor blockade, duration of analgesia, and any complication. SETTINGS AND
DESIGN: This was a randomized controlled trial conducted in the Department of Anesthesiology, a tertiary care hospital.
MATERIALS AND METHODS: Sixty consecutive patients of the American Society of Anesthesiologists physical status Class I and II who were posted for upper limb surgeries were recruited. Patients were divided into two groups of thirty patients each. Group T (tramadol) received 20 ml of 0.5% levobupivacaine with 100 mg tramadol, and Group D (dexamethasone) received 20 ml of 0.5% levobupivacaine with 8 mg dexamethasone under ultrasound guidance. Sensory and motor block assessment was done every 2 min until the development of complete sensory and motor block till 45 min. Verbal numerical rating scale score was assessed in postoperative ward at regular intervals. Patients were followed up to check for any residual neurological deficits.
RESULTS: There was no statistical difference in demographic data between the two groups. The onset time of sensory and motor blockade shows no significant difference between groups. The mean time duration of motor blockade in Group T was 764.63 min and for Group D was 1150.27 min which was statistically significant (P < 0.05). The duration of analgesia in Group D was 1300.83 min and in Group T was 820.47 min which was statistically significant (P < 0.05). Side effects such as nausea, vomiting, pruritis, hypoxemia, and long-term neurological deficits were not reported in any of the patients in either group.
CONCLUSION: Dexamethasone 8 mg as an adjuvant to 0.5% levobupivacaine for supraclavicular brachial plexus block using ultrasound guidance increases the duration of analgesia in comparison to 100 mg tramadol and provides excellent postoperative pain-free period without any neurological deficits.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Brachial plexus block is especially intended for the upper limb surgeries. Brachial plexus block avoids unwanted complications due to administration of various drugs in general anesthesia and in the process of upper airway instrumentation. There are various approaches to brachial plexus block, but the supraclavicular approach is the most common approach to brachial plexus because of compact arrangement of the nerve trunks. Use of ultrasound for the performance of supraclavicular block has become the gold standard since it enables the clinician to deposit the local anesthetic close to the nerves in real time and is usually devoid of complications.

Peripheral nerve blocks are usually performed using conventional local anesthetics. Bupivacaine has been extensively studied in brachial plexus block. Levobupivacaine is a long-acting local anesthetic with lesser cardiotoxicity and neurotoxicity than bupivacaine. The mechanism of action of levobupivacaine is similar to that of racemic bupivacaine. When the minimum local analgesic concentration is reached close to the membranes of the axons, the molecules block the sodium channels, in the resting position. In this way, the transmission of the nerve impulses stops. As levobupivacaine is less cardio and neurotoxicity compared to racemic bupivacaine, it is considered to be safer to use when compared to bupivacaine.

Adjuvants are added to decrease the dose of local anesthetic and to improve quality and duration of analgesia. Adjuvants such as dexamethasone, tramadol are added to local anesthetics to improve the quality of nerve blocks.

Tramadol is an analgesic with mixed opioid and nonopioid activity. Tramadol seems to pass the neuronal membrane and diffuse within the interstitial or axonal fluid since it is a lipophilic drug.[1] The nonopioid activity is through alpha two agonist mechanism and serotonin and noradrenaline reuptake inhibition in central nervous system. It inhibits the reuptake of norepinephrine and serotonin from the nerve endings, and it is supposed to potentiate the effect of local anesthetics when mixed together.[2345]

Steroids induce a degree of vasoconstriction which results in reduced local anesthetic absorption.[6] Steroids suppress the synthesis and secretion of various inflammatory mediators which prolongs the period of analgesia.[7891011] Dexamethasone acts on glucocorticoid receptor which increases the activity of inhibitory potassium channels on nociceptive C-fibers which prolongs the duration of local anesthesia.[12131415] The study was done to evaluate the efficacy of 100 mg tramadol, or 8 mg dexamethasone added as an adjuvant to 20 ml of 0.5% levobupivacaine in ultrasound-guided supraclavicular brachial plexus block for prolongation of postoperative analgesia for the upper limb surgery.

Aims and objectives

To assess and compare the efficacy of dexamethasone or tramadol when added to levobupivacaine in supraclavicular brachial plexus block for upper limb surgeries with regard to:

Onset time for complete sensory blockade

Onset time for complete motor blockade

MATERIALS AND METHODS

After obtaining Institutional Ethical Committee approval and informed patient consent, sixty adult patients of the American Society of Anesthesiologists Physical Status I and II who were scheduled for elective upper limb surgeries aged 18–65 years were included for this double-blinded, randomized controlled study. Patients with previous history or clinical presentation with central or peripheral neurological disease, coagulopathy, infection at the site of injection, patient allergic to any of the study drugs and those unable to cooperate were excluded from the study. Assuming a prolongation in duration of postoperative analgesia by 120 min; the calculated sample was 29 in each group with power of 0.8 and α error of 0.05.

Patients were premedicated with oral tablet alprazolam 0.5 mg and tablet ranitidine 150 mg, night before surgery and day of surgery. After arrival in the operating theater, an 18G intravenous (IV) cannula was secured. Patients were optimally positioned for the performance of ultrasound-guided supraclavicular brachial plexus block. Standard monitoring was used throughout the procedure, including noninvasive blood pressure, electrocardiogram and pulse oximetry. All patients received IV midazolam 0.03 mg/kg before the block for anxiolysis. An anesthesiologist who was not involved in the procedure prepared the study drugs according to the randomization as per sealed envelope technique. Another anesthesiologist blinded to the study drugs performed the block procedures and recorded all the data. Patients received supraclavicular brachial plexus block with 20 ml of 0.5% levobupivacaine with adjuvant. Group tramadol (Group T) - thirty patients received local anesthetic mixture containing 20 ml of 0.5% levobupivacaine plus 2 ml of tramadol (1 ml = 50 mg). Group dexamethasone (Group D) - thirty patients received local anesthetic mixture containing 20 ml of 0.5% levobupivacaine plus 2 ml of dexamethasone (1 ml = 4 mg) [Figure 1]. Time at which drug was injected was noted. Patients were evaluated every 2 min till the development of complete sensory and motor block till 45 min. Patients in whom complete sensory or motor blockade was not achieved at the end of 45 min were excluded from the study, and further anesthetic management was decided by attending anesthesiologist. Sensory block was confirmed by loss of cold sensation using ether-soaked cotton in all dermatomes supplied by the brachial plexus. Sensory block was assessed by three-point qualitative scale (perseverance of cold sensation to ether-soaked cotton). Scale 2 - perceives both touch and temperature, Scale 1 - perceives only touch, Scale 0 - neither perceives touch nor temperature in the territory of musculocutaneous nerve, median nerve, ulnar nerve, and radial nerve (RN).

Figure 1

CONsolidated Standards of Reporting Trials 2010 flow sheet

Similarly, motor blockade was assessed on a three-point qualitative scale. Scale 2 - normal motor function (power 4/5, 5/5), Scale 1 - weakness against resistance (power 3/5, 2/5), Scale 0 - paresis/no motor power (power 0/5, 1/5) for the four terminal branches. Elbow flexion, wrist flexion, finger abduction, and wrist extension was assessed for musculocutaneous, median, ulnar, and RN, respectively. When patients were not able to move or raise the hand actively, the block was considered as the complete motor block, and the time was noted and recorded as onset of motor blockade. Readiness for surgery was decided by loss of surgical site pain while attempting motor maneuvers, at least Scale 1 sensory and motor loss in all four nerve territories. Inadequate block was considered whenever the patient complained of pain and the anesthetic management was decided by the attending anesthesiologist and the patient was to be excluded from the study.

At the end of surgery, the patient was transferred to postanesthesia care unit where block regression and postoperative pain were assessed. Verbal numerical rating scale (VNRS) was used to evaluate and record pain in the recovery room after arrival at 0, 2, 4, 6, 8, 10, 12, 24, and 48 h. When VNRS score was four or more, injection paracetamol 1 g was administered as a slow intravenous infusion over a period of 30 min as rescue analgesia.

During the same intervals, motor recovery was assessed by the patient's ability to squeeze the examiners hand. Duration of motor blockade was noted as time gap between onset of motor blockade and scale two motor power on finger flexion. Duration of analgesia was defined as time lapse between onset of sensory blockade and patient's pain score (VNRS) reaching more than 4 and administration of rescue analgesia.

Patients were monitored for 24 h for the presence of complications and side effects including pruritus, nausea and vomiting. Twenty-four hours later, sensory and motor assessment was performed to determine any residual block or neurological deficit for 48 h. Patients were followed up to look for any residual neurological deficit.

RESULTS

The mean age of patients in Group D was 37 ± 13 years and in Group T was 42 ± 13 years. There was no statistical difference in age distribution between two groups (P = 0.182).

There were 12 female and 18 male patients in Group D and in Group T had 10 female and 20 male patients. There was no statistical difference in sex distribution between two groups (P = 0.789).

The number of bony procedures and soft tissue procedures were comparable between both the Group D and Group T (P = 0.551). The block was effective in all the patients, and none of them were excluded from the study.

The mean onset time of sensory block in Group D was 5.80 ± 1.97 min and in Group T was 6.33 ± 3.71 min. There was no statistical difference between the two groups (P = 0.490).

The mean onset time of motor blockade following supraclavicular brachial plexus block in Group D was 13 ± 4.8 min and 15 ± 5.3 min in Group T. There is no statistically significance in onset of motor blockade between two groups (P = 0.039).

The mean time duration of analgesia in Group D was 1300.83 min and in Group T was 820.47 min, and this was statistically significant (P < 0.001). Patients in dexamethasone group had more prolonged duration of analgesia when compared to tramadol group [Table 1].

Table 1

Duration of analgesia

The mean duration of motor blockade for Group D was 1150.27 min and in Group T was 764.63 min. The difference in duration of motor block in two groups was statistically significant (P < 0.001) [Table 2].

Table 2

Duration of motor blockade

Side effects such as nausea, vomiting, pruritis, hypoxemia, and long-term neurological deficits were not reported in any of the patients in either group.

DISCUSSION

In this study, we performed ultrasound-guided supraclavicular block on patients undergoing upper limb surgery. We have compared tramadol and dexamethasone as adjuvants to levobupivacaine for the performance of ultrasound-guided supraclavicular block. We studied the onset of sensory and motor blockade, duration of motor blockade, and duration of analgesia. To the best of our knowledge, there are no studies comparing tramadol and dexamethasone as adjuvants to levobupivacaine for performing ultrasound-guided supraclavicular brachial plexus block.

The supraclavicular block is a widely used regional nerve block in upper limb surgeries. It provides anesthesia for entire upper limb procedures in a consistent manner. It is carried out in the division level of the brachial plexus and with high volume; the trunk level of the plexus may also be blocked in this approach.

The previous studies have shown that ultrasound-guided supraclavicular block extends the duration of analgesia in comparison to landmark-guided block as there it allows more accurate drug deposition closer to the nerve fibers.[16] Using ultrasound, the incidence of block-related complications is reduced when compared to landmark-guided approach.[17] Abrahams et al. concluded that blocks performed using ultrasound guidance were more likely to be successful, took less time to perform, had faster onset of action, and had longer duration of blockade than those performed with peripheral nerve stimulation guidance.[18] Ultrasound guidance also decreased the risk of vascular puncture during block performance.

In our study, with real-time deposition of 100 mg of tramadol as an adjuvant to 20 ml of 0.5% levobupivacaine using ultrasound guidance, we have observed the mean duration of analgesia as 820 ± 239 (13.6 ± 3.98 h) min. Shrestha et al. studied the role of tramadol when added as an adjuvant to bupivacaine in landmark-guided supraclavicular brachial plexus block and observed the mean duration of analgesia was 453.17 (7.5 h) min.[19] Compared to other studies, we have achieved an increase in postoperative analgesia time to nearly 6 h. This could be due to real time deposition of drug mixture near the brachial plexus using ultrasound. The additive effect of tramadol to increase the duration of analgesia may be due to its central and peripheral analgesic effects. It is a weak μ-opioid receptor agonist and also prevents reuptake of noradrenaline and serotonin and enhances both serotonin and noradrenaline release. The monoaminergic activity of tramadol increases the inhibitory activity of the descending pain pathways, thus resulting in a suppression of nociceptive transmission at the spinal level. Christiansson concluded that addition of 100 mg tramadol to brachial plexus block prolongs the duration of the sensory and motor block significantly.[20]

In our study, we have used 8 mg of dexamethasone as an adjuvant to 20 ml of 0.5% levobupivacaine and observed that mean duration of analgesia was 1301 ± 336 min (21.68 ± 5.6 h). Shrestha et al. in their study concluded that 8 mg of dexamethasone when added to bupivacaine in supraclavicular brachial plexus block using surface landmark guidance, the mean duration of analgesia was 1028.17 min.[10] There is a significant increase in postoperative analgesia time. This could be due to the deposition of drug near the supraclavicular brachial plexus using ultrasound guidance as previously discussed. Cummings et al. conducted a study with a hypothesis that the addition of dexamethasone to local anesthetics such as ropivacaine and bupivacaine for interscalene plexus nerve blockade significantly prolonging the duration of analgesia and observed that dexamethasone prolongs analgesia of interscalene blocks performed under ultrasound guidance.[6] When dexamethasone used as an adjuvant to either ropivacaine or bupivacaine provided nearly 22 h of analgesia in both the groups. This increase in postoperative analgesia is due to action of dexamethasone on glucocorticoid receptor to alter the function of ion channel or produce local acidosis in nerve cell. By this action, it reduces the concentration of local anesthetic required to produce conduction blockade or trapping the highly ionized levobupivacaine molecule into the neuronal cell. These events cause an extended action of local anesthetics.

In our study, the onset time of complete sensory blockade in tramadol group was 6.3 ± 3.7 min and onset of complete motor blockade in tramadol group was 13 ± 4.79 min, and the onset time of complete sensory blockade in dexamethasone group was 5.8 ± 1.9 min and onset time for complete motor blockade was 15.3 ± 5.3 min which does not show much difference statistically. In both the groups, the decrease in onset time of complete sensory and motor blockade is due to the more precise deposition of the drug mixture near the supraclavicular brachial plexus under the guidance of ultrasound.

Shrestha et al. compared tramadol and dexamethasone as an adjuvant to bupivacaine for supraclavicular brachial plexus block using surface landmark technique and showed the mean onset time for sensory blockade in tramadol group were 18.47 min and for dexamethasone group was 16.76 min. The mean onset time for motor blockade in tramadol group was 12.90 min, and dexamethasone group was 13.43 min.[19] Compared to other previous studies which were done using landmark-guided technique or using nerve stimulator technique for supraclavicular brachial plexus block, ultrasound technique provides quicker onset time of sensory and motor blockade.

Patients were followed up to look for any residual neurological deficit. None of the patients had any residual neurological deficits.

CONCLUSION

Dexamethasone 8 mg as an adjuvant to 0.5% levobupivacaine for supraclavicular brachial plexus block using ultrasound guidance increases the duration of analgesia in comparison to 100 mg tramadol and provides excellent postoperative pain-free period without any neurological deficits.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.