thesis

1. Comparison of Clonidine and Dexmedetomidine as an Adjuvant to 0.5% Ropivacaine
Journal on Recent Advances in Pain, September-December 2015;1(2):73-77 73
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Comparison of Clonidine and Dexmedetomidine as
an Adjuvant to 0.5% Ropivacaine in Supraclavicular
Brachial Plexus Block: A Prospective, Randomized,
Double-blind and Controlled Study
1
Usha Bafna, 2
Gaurav Sharma, 3
Sindhu Sapru, 4
Mamta Khandelwal, 5
Varsha Kothari, 6
Rajni Mathur
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Original Article
10.5005/jp-journals-10046-0015
ABSTRACT
Background: Brachial plexus blockade is the cornerstone of
regional anesthesia practice. This study was done to compare
clonidine and dexmedetomidine as an adjuvant to 0.5%
ropivacaine in supraclavicular brachial plexus block (SCB).
Materials and methods: A prospective, randomized,
double-blind study was done in 120 patients of American
Society of Anaesthesiologist (ASA) grade I and II undergoing
elective upper limb surgery under SCB. Patients were
randomized into three groups. Group 1 (n = 40) received
30 ml of 0.5% ropivacaine, group 2 (n = 40) received 30 ml
of 0.5% ropivacaine with 2 mg/kg clonidine, and group 3
(n = 40) received 30 ml of 0.5% ropivacaine with 1 mg/kg
dexmedetomidine. Onset and recovery time of sensory
and motor block, duration of analgesia and quality of block,
hemodynamic variables, and level of sedation were studied in
the three groups.
Results: Sensory and motor block onset times were shorter in
group 3 than in group 1 and 2 (p < 0.0001). Sensory and motor
block durations and duration of analgesia were longer in group 3
than in groups 1 and 2 (p < 0.0001). Blood pressure and heart
rate were lower in group 3 as compared to groups 1 and 2 (p <
0.0001). The number of patients achieving grade IV quality of
block was higher in group 3 as compared to the other groups.
Conclusion: Dexmedetomidine when added in SCB shortened
the onset of sensory and motor block and enhances the duration
of sensory and motor block and duration of analgesia without
significant side effects.
Keywords: Clonidine, Dexmedetomidine, Ropivacaine,
Supraclavicular brachial plexus block.
How to cite this article: Bafna U, Sharma G, Sapru S,
Khandelwal M, Kothari V, Mathur R. Comparison of Clonidine
and Dexmedetomidine as an Adjuvant to 0.5% Ropivacaine
in Supraclavicular Brachial Plexus Block: A Prospective,
Randomized, Double-blind and Controlled Study. J Recent Adv
Pain 2015;1(2):73-77.
Source of support: Nil
Conflict of interest: None
Introduction
Brachial plexus blockade is one of the approaches to
sensorimotor regional neural blockade by which surgical
anesthesia of the upper limb may be achieved. It is
preferred in upper limb surgeries because it has certain
advantages.1,2
It is safer in patients who are at high risk
for general anesthesia, provides good postoperative
analgesia and is economical.
The supraclavicular approach to brachial plexus block
provides anesthesia of the entire upper extremity in the
most consistent and time efficient manner. It has a high
success rate and rapid onset of action. It provides more
complete anesthesia of the plexus, particularly the axillary
and musculocutaneous nerves, and does not require
abduction of the arm to be performed.3,4
Peripheral nerve
blocks have an increasingly important role in ambulatory
anesthesia.5
Various studies have investigated several adjuvants
like adrenaline, dextran 10%, potassium chloride,
neostigmine, opioids, tramadol, dexamethasone,
clonidine, bicarbonate and dexmedetomidine with the
local anesthetics.6-11
Clonidine, a selective alpha 2 adrenergic agonist, has
been used traditionally as an antihypertensive agent.
Various studies have shown that clonidine can be used
as an adjunct to local anesthetics in peripheral nerve
blocks.12
In one study, author concluded that addition of 150 mg
of clonidine to ropivacaine for axillary brachial plexus
blockade prolongs motor and sensory block without an
increase in the incidence of side effects.13
Dexmedetomidine was introduced two decades ago
as a sedative and supplementation to sedation in the
intensive care unit for intubated patients. Studies have
shown that dexmedetomidine is more specific for α-2
adrenoreceptors than clonidine (ratio of α-2:α-1 activity,
1620:1 for dexmedetomidine, 220:1 for clonidine).14,15
1,5,6
Professor, 2
Assistant Professor, 3
Senior Resident
4
Associate Professor
1-6
Department of Anesthesiology, SMS Medical College, Jaipur
Rajasthan, India
Corresponding Author: Gaurav Sharma, Assistant Professor
Department of Anesthesiology, SMS Medical College, Jaipur
Rajasthan, India, e-mail: gauravjln@yahoo.co.in

2. Usha Bafna et al
74
Swami et al compared the effects of clonidine (2 mg/
kg) and dexmedetomidine (1 mg/kg) added to 35 cc 0.5%
bupivacaine in supraclavicular brachial plexus block.21
The aim of our study was to compare the effect
of clonidine 2 ug/kg and dexmedetomidine 1 ug/kg
added to ropivacaine 0.5% on the onset and duration of
sensory and motor block, and total duration of analgesia,
as primary outcome. Effect on hemodynamic variables,
sedation score and the side effects, i.e. hypotension,
bradycardia, headache, dryness of mouth, nausea and
vomiting were also evaluated. This study was done to
find a better additive in SCB along with 0.5% ropivacaine.
We have used ropivacaine because it is less cardiotoxic
than bupivacaine.
MATERIALs AND METHODs
This study was conducted in the Department of
Anesthesiology, SMS Medical College, Jaipur. The
approval for the study was taken from the institutional
ethics committee. This prospective, randomized, double-
blind study was done in 120 patients, of American Society
of Anaesthesiologist (ASA) grade I and II, age 20 to 50
years, body weight 50 to 80 kg who underwent elective
surgery in upper limb.
All patients not willing to participate in the study,
uncooperative patients, patients who were having local
pathology at the site of injection or disability, history of
convulsion, allergy to the drug used, bleeding disorder,
severe neurological deficit, and patients in whom block
was incomplete were excluded from the study.
Pre-anesthetic checkup (PAC) was done a day before
the surgery that included complete history of patients
including any known drug allergy, general and systemic
examination and local examination of supraclavicular
area. Pulse rate, blood pressure, respiratory rate
and weight of the patient were noted. All routine
investigations were done in all patients.
Informed consent was obtained for performance of
block after complete explanation about the study protocol
and the procedure. Visual analog scale (VAS) 0 to 10 was
explained to the patient.
The patients were randomized into three groups each
consisting of 40 patients by chit in box method. A total of
120 chits (40 per group) were made, each chit mentioning
a particular study group. The patients were asked to pick
up a chit from the box. Patients were allocated to the
group mentioned on chit. Study drugs were prepared
and administered to patients as per their respective
allotted groups.
Group 1 (n = 40) received 30 ml of 0.5% ropivacaine,
group 2 (n = 40) received 30 ml of 0.5% ropivacaine with
2 mg/kg clonidine, and group 3 (n = 40) received 30 ml
of 0.5% ropivacaine with 1 ug/kg dexmedetomidine. All
the solutions were diluted with isotonic normal saline to
make a total volume of 32 ml.
Fasting status, consent and PAC were checked and
intravenous access was secured. The patient was placed
in the supine position, with the head turned away and
the ipsilateral arm adducted. The interscalene groove
and mid-point of the clavicle and subclavian artery were
identified. After aseptic preparation of the area, at a point
1.5 to 2.0 cm posterior to midpoint of the clavicle, a skin
wheal was raised with a local anesthetic (lignocaine 2%
plain). Next, a 22 gauge, 50 millimeter ‘short beveled’
needle was passed through the same point in a caudal,
slightly medial and posterior direction, until either a
paresthesia was elicited or the first rib was encountered.
If the first rib was encountered, the needle was moved
over the first rib until a paresthesia was elicited either in
the hand or arm. After eliciting paresthesia and negative
aspiration of blood, medication was injected as per the
respective group allotment.
After performance of nerve block patients were
evaluated for onset of sensory block every 1 minute. The
sensory block was assessed by pin prick with 25 gauge
needle in C5-6 dermatome (Table 1). The onset time of the
sensory block was taken as the time interval in minutes
from the time of injection of the drug, till the sensory
block started appearing, i.e. score > 1.
Motor block was assessed by using modified Bromage
scale (Table 2).
The onset time of the motor block (OTMB), i.e. MBS
score = 1, were recorded in all patients.
Heart rate, noninvasive blood pressure and SPO2
were measured every 5 minutes for first half an hour and
thereafter every 15 minutes. Intraoperatively sedation
was assessed by using a four point scale at 15 minutes
interval. Postoperatively heart rate, noninvasive blood
pressure, sensory block and motor power, sedation
score were recorded at every 30 minutes interval. Visual
analog scale score was assessed postoperatively at 6, 12
and 18 hours. Rescue analgesia was given at VAS score
of 3. Tramadol injection 100 mg IV was given as rescue
Table 1: Sensory block assessment
Score Criteria
0 Sharp pain
1 Touch sensation only
2 Not even touch sensation
Table 2: Motor block assessment (modified Bromage scale)
Score Criteria
0 No block—total arm and forearm flexion
1 Partial block—total forearm and partial arm flexion
2 Almost complete block—inability to flex the arm and
decreased ability to flex the forearm
3 Total block—inability to flex both the arm and forearm

3. Comparison of Clonidine and Dexmedetomidine as an Adjuvant to 0.5% Ropivacaine
Journal on Recent Advances in Pain, September-December 2015;1(2):73-77 75
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Table 4: Onset of sensory and motor block, total duration of
sensory and motor block, total duration of analgesia
Parameters Group 1 Group 2 Group 3
Onset of sensory
block in minute
(mean ± SD)
12.2 ± 3.1 10.7 ± 4.0 4.9 ± 1.0
Onset of motor
block in minute
(mean ± SD)
15.8 ± 3.2 12.1 ± 4.1 8.9 ± 1.4
Duration of anal-
gesia in minute
(mean ± SD)
510.7 ± 45.3 713.2 ± 30.2 1014.2 ± 68.0
Duration of motor
block in minute
(mean ± SD)
460.5 ± 45.3 626.2 ± 33.4 769.2 ± 42.7
Duration of sensory
block in minute
(mean ± SD)
483.5 ± 47.0 675 ± 26.8 844 ± 40.5
analgesic. Total duration of analgesia was defined as the
time from injection of drug administration to patient’s
first request for rescue analgesic (i.e. at VAS 3).
The duration of motor block was defined as the
time of attainment of Bromage score 3 of block (onset)
until reversal to Bromage score 1. The incidence of
adverse effects, such as nausea, vomiting, headache,
bradycardia, respiratory depression, and hypotension
were recorded. Hypotension, defined as a decrease of
systolic blood pressure by more than 30% from baseline
or a fall below 90 mm Hg, was treated with incremental
IV doses of mephentermine 5 mg and IV fluid as required.
Bradycardia, defined as heart rate < 50 bpm, were treated
with IV atropine 0.3 to 0.6 mg. Patients were monitored
for 24 hours in postoperative period for adverse effects.
STATISTICS
A study power 80% and alpha level of 0.05 sample size
was calculated for 3 groups (40 patients in each group).
Aimed sample size was 120 patients.
Comparison between the three groups with respect
to demographic variables, intraoperative vitals HR, BP,
RR, SPO2, the onset and duration of sensory and motor
blocks were analyzed by using unpaired t-test. p-value
<0.05 was considered significant.
RESULTS
Mean age, body weight, ASA grading and duration of
surgery were similar in the three groups (Table 3).
The onset of sensory block was 12.2 ± 3.16 minutes in
group1,10.7±4.05minutesingroup2and4.9±1.08minutes
in group 3. It was found to be statistically significant
when we compared group 3 to groups 1 and 2 (p < 0.0001)
(Table 4).
The onset of motor block took 15.8 ± 3.29 minutes in
group 1, 12.1 ± 4.11 minutes in group 2, and 8.9 ± 1.41
minutes in group 3. It was statistically significant when
we compared group 3 to groups 1 and 2 and group 2 to
group 1 (p < 0. 0001) (Table 4).
Duration of analgesia was 510.75 ± 45.31 minutes in
group 1, 713.25 ± 30.24 minutes in group 2 and 1014.25 ±
68.00 in group 3. It was statistically significant when
we compared group 3 to group 1 and 2 and group 2 to
group 1 (p < 0.0001) (Table 4).
Duration of motor block was 460.5 ± 45.344 minutes in
group 1, 626.25 ± 33.42 minutes in group 2 and 769.25 ±
42.75 in group 3. It was statistically significant when we
compared group 3 to groups 1 and 2 and group 2 to group
1 (p < 0. 0001) (Table 4).
Duration of sensory block was 483.5 + 47.09 minutes
in group 1, 675 + 26.89 minutes in group 2 and 844 + 40.56
minutes in group 3. It was statistically significant when
Table 3: Demographic profile
Variables
Group 1
(n = 40)
Group 2
(n = 40)
Group 3
(n = 40) p-value
Age (years)
(mean ± SD)
34.2 ± 10.1 31.9 ± 12.9 25.8 ± 7.5 1.0
Body weight
(kgs) (mean
± SD)
56.8 ± 4.2 51.5 ± 7.7 56.4 ± 3.0 0.9
Duration
of surgery
(minute)
(mean ± SD)
72.5 ± 14.8 71.2 ± 12.5 72.2 ± 16.7 2.0
ASA grade I/II 18/22 21/19 24/16 1.8
Gender (M/F) 23/17 26/14 29/11 0.7
p-value Groups 1 and 2 Groups 1 and 3 Groups 2 and 3
Onset of
sensory
0.0565 <0.0001 <0.0001
Onset of
motor
<0.0001 <0.0001 <0.0001
Duration of
analgesia
<0.0001 <0.0001 <0.0001
Duration of
motor block
<0.0001 <0.0001 <0.0001
Duration
of sensory
block
<0.0001 <0.0001 <0.0001
we compared groups 3 to groups 1 and 2 and group 2 to
group 1 (p < 0. 0001) (Table 4).
Mean pain score in group 1 was 2.65 + 0.48, in group 2
was 1.275 + 0.45 and in group 3 was 0.25 + 0.439. The mean
pain score in group 3 is significantly lower as compared
to groups 1 and 2.
In group 1, all 40 patients were awake and alert. In
group 2 (27/40) were awake and alert and 13 patients
were drowsy. In group 3(18/40) were awake and alert
and 22 patients were drowsy (Table 5).
There was no significant difference between groups
regarding the incidence of adverse effects (Table 6).

4. Usha Bafna et al
76
DISCUSSION
Brachial plexus block was achieved by classical supra-
clavicular approach and satisfactory surgical anesthesia
was attained in all the cases for various types of upper
limb surgeries.
A 2 mg/kg body weight of clonidine was added with
ropivacaine in one group of patients based on works done
by El Saied et al which concluded that addition of 150 mg
of clonidine to ropivacaine for axillary brachial plexus
blockade prolongs motor and sensory block without an
increase in incidence of side effects.13
In contrast, Culebras et al showed that clonidine
(150 mg) added to 40 ml 0.5% bupivacaine did not prolong
postoperative analgesia.16
Casati evaluated the effects of clonidine 1 ug/kg
added to ropivacaine and found longer onset time to
establish block in clonidine group.17
Bernard et al observed that small doses of clonidine
30 to 90 mg in combination with lidocaine administered
in axillary block reduced sensory block onset time and
significantly prolonged the duration of analgesia (p <
0.01). In this study higher doses of clonidine (300 mg) were
associated with significant adverse effects.18
Wolfgang et al studied the effect of clonidine as
adjuvant for bupivacaine, mepivacaine and ropivacaine
foraxillaryplexusblock.Clonidineproducedprolongation
in bupivacaine and mepivacaine groups but did not
produce additional block in ropivacaine group.19
Aliya Esmaoglu et al have reported that 100 ug dose
of dexmedetomidine when used as an adjuvant for
ropivacaine in axillary block shortens the onset of sensory
and motor block and prolongs duration of blockade
without significant change in heart rate, blood pressure
and sedation.20
Swamietalcomparedtheeffectsofclonidine(2ug/kg)
and dexmedetomidine (1 mg/kg) added to 35 cc 0.5%
bupivacaine in supraclavicular brachial plexus block
and found that dexmedetomidine enhanced the duration
of sensory and motor block and also the duration of
analgesia. In our study, we observed that both clonidine
and dexmedetomidine have enhanced the duration of
sensory and motor block and duration of analgesia.21
RachanaGandhietalobservedan8hoursprolongation
in duration of analgesia and motor block when 30 mg
dexmedetomidine was added to bupivacaine.22
In another study, Kenan kayqusuz et al observed a
3.5 hours prolongation of analgesia when dexmedetomi-
dine 100 mg was added to levobupivacaine. In our study,
we have found a significant prolongation of analgesia
(5 hours) with dexmedetomidine compared to clonidine.
This shows that the dose of dexmedetomidine of 1 mg/kg
is appropriate for brachial plexus block and in fact supe-
rior to a higher dose of clonidine (2 mg/kg).23
In our study in groups 1 and 2, no significant change
in heart rate was seen in the intraoperative as well as
postoperative period. However in group 3 statistically
significant reductions in heart rate were observed.
These results are consistent with the studies done by
Adnan et al24
and Swami et al who found no change
in heart rate with clonidine in axillary brachial block,
and supraclavicular brachial plexus block respectively;
and to the results of Aliya Esmaoglu et al and Swami
et al who described significant bradycardia with
dexmedetomidine.20,21
Blood pressure (both systolic and diastolic) showed no
difference in groups 1 and 2. The blood pressure values in
group3showedsignificantreductionbothintraoperatively
and postoperatively as compared to baseline values but no
active clinical intervention was required. These findings
are in line with the works of El Saied et al who found
no significant changes in blood pressure when 150 mg
clonidine was added to ropivacaine. Aliya Esmaoglu
et al and Swami et al have observed a decrease in the
blood pressure and heart rate when dexmedetomidine
was added to local anesthetic in brachial plexus block.
CONCLUSION
Theupperlimbsurgeriesperformedundersupraclavicular
brachial plexus nerve block with 0.5% ropivacaine and
dexmedetomidine (1 mg/kg) as an adjuvant result in
early onset of sensory and motor blockade, prolongation
of the duration of sensory and motor blockade and
postoperative analgesia with better quality of block as
compared to clonidine (2 mg/kg). The patient remained
comfortable in postoperative period with considerable
therapeutic benefit and without any potential adverse
effects.
Table 6: Adverse effect
Sl. no. Adverse effects Group 1 Group 2 Group 3
1 Hypotension 0 0 1
2 Bradycardia 0 0 2
3 Nausea/vomiting 0 0 0
4 Headache 0 0 0
5 Dryness of mouth 0 0 0
Table 5: Degree of sedation
Score Degree of sedation Group 1 Group 2 Group 3
1 Awake and alert 40 27 18
2 Drowsy but responsive
to command
0 13 22
3 Very drowsy but
responsive to pain
0 0 0
4 Unresponsive 0 0

5. Comparison of Clonidine and Dexmedetomidine as an Adjuvant to 0.5% Ropivacaine
Journal on Recent Advances in Pain, September-December 2015;1(2):73-77 77
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