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TRANSCRIPT
COMPARISON OF 0.5% LEVOBUPIVACAINE AND 0.5% ROPIVACAINE FOR INFRACLAVICULAR BRACHIAL
PLEXUS BLOCK
DR RAMANESH MAGESWARANM.B.B.S. (MANIPAL)
DISSERTATION SUBMITTED IN PARTIAL FULFILMENT FOR THE DEGREE IN MASTER OF MEDICINE
(ANAESTHESIOLOGY)
FACULTY OF MEDICINEUNIVERSITI KEBANGSAAN MALAYSIA
KUALA LUMPUR
2009
CONTENTS PAGE
Acknowledgement ii
Declaration iii
Abstract iv
Abstrak v
Introduction 1
Objectives 3
Materials and Methods 4
Results 8
Discussion 13
Conclusion 16
References 17
ACKNOWLEDGEMENT
I extend my deepest gratitude to:-
Associate Professor Dr Choy Yin Choy, Consultant Anaesthetist, Faculty of Medicine, Universiti
Kebangsaan Malaysia, for his guidance, advice and help throughout this study.
Dr.As Niza Bin Sulong, Head of Department and Consultant, Department of Anaesthesia and
Intensive Care, Hospital Taiping, who encouraged me to pursue my dream in becoming an
anaesthesiologist.
Dr Teoh Chuan Yeong, Specialist Anaesthetist, Faculty of Medicine, Universiti Kebangsaan
Malaysia, for his enthusiasm and encouragement surrounding this study.
And finally, thanks to my family for their love, support and understanding during my training.
DECLARATION
I certify that this dissertation does not incorporate without acknowledgement any material
previously submitted for a degree or diploma in any university, and that to the best of my knowledge
and belief it does not contain any material previously published or written by another person where
due reference is not made in the text.
5th December 2008 --------------------------------------- Dr. Ramanesh A/L Mageswaran
P33097
ABSTRACT
A prospective, randomized double-blind study was conducted in 60 ASA 1-2 patients, aged 18-65
years old, who were undergoing elective or emergency orthopedic upper limb surgery. They were
randomly divided into two groups :- Group I received 30mLs of 0.5% Ropivacaine; and Group II
received 0.5% Levobupivacaine. Infraclavicular brachial plexus block based on the coracoid
approach was used. The time required for the absence of sensation to pin prick at each dermatome
and onset of motor block was documented. Pain score using (100mm) Visual Analogue Score was
charted every 30 minutes during surgery and at 6 hours. The mean onset time (SD) for sensory block
with Ropivacaine (Group I) was 13.5 ± 2.9 minutes compared to Levobupivacaine (Group II) at 11.1
± 2.6 minutes. The onset for motor block was 19.0 ± 2.7 minutes in Group I compared to 17.1 ± 2.6
minutes in Group II. Pain was assessed by using (100mm) Visual Analogue Score. Patients in the
two groups experienced both mild to moderate pain at 6 hours. In conclusion, there was a statistical
difference in terms of onset of sensory and motor block when 0.5% Levobupivacaine was used
compared to 0.5% Ropivacaine for infraclavicular block below elbow surgery. However, there was
no difference in terms of effectiveness of analgesia 6 hours post operatively between both the drugs.
ABSTRAK
Satu kajian, prospektif, rabun dua hala telah dilakukan ke atas 60 pesakit ASA1-2, berumur 18-65
tahun, yang menjalani pembedahan elektif atau kecemasan ortopedik pada bahagian otot. Mereka
dibahagikan secara rambang kepada dua kumpulan :- Kumpulan I menerima 30mLs 0.5%
Ropivacaine; dan Kumpulan II menerima 30mLs 0.5% Levobupivacaine. Teknik coracoid telah
digunakan untuk blok infraclavicular. Tempoh masa untuk hilang sensasi terhadap cucukan jarum
pada setiap dermatom dan masa kehilangan fungsi motor direkodkan. Skala scor kesakitan
menggunakan (100mm) Visual Analogue Score dicatatkan setiap 30 minit dan pada jam ke-6
pembedahan. Purata masa untuk blok bermula dari segi sensori adalah 13.5 ± 2.9 minit untuk
Ropivacaine (Kumpulan I) berbanding dengan 11.1 ± 2.6 minit untuk Levobupivacaine (Kumpulan
II). Purata masa untuk motor blok adalah 19.0 ± 2.7minit untuk Kumpulan I berbanding dengan 17.1
± 2.6 minit untuk Kumpulan II. Kesakitan dikaji dengan menggunakan (100mm) Visual Analogue
Score. Pesakit dalam kedua-dua kumpulan mengalami kesakitan pada tahap minima and sederhana
pada jam ke-6 pembedahan. Kesimpulannya, ada perbezaan yang ketara dari segi sensori dan motor
apabila 0.5% Levobupivacaine telah digunakkan berbanding dengan 0.5% Ropivacaine untuk blok
infraclavicular untuk pembedahan bawah siku. Walaubagaimanapun, tiada perbezaan ketara diantara
kedua-dua bius tersebut dari segi analgesia pada jam ke-6 selepas pembedahan.
INTRODUCTION
Regional anaesthesia, particularly peripheral nerve blockade is useful for orthopedic patients. These
techniques are often used to provide not only anaesthesia but also post operative analgesia after limb
surgery1.
Brachial plexus block offers many advantages (eg. sympathectomy, better post-operative analgesia,
fewer side effects) over general anesthesia in upper limb surgeries.
Introduction of long acting local anesthetic with better safety profile as well as better equipment has
further increased the usage of peripheral nerve blocks. Supraclavicular block as opposed to
infraclavicular brachial plexus block generally offers more dense and complete upper limb
anaesthesia but with a higher risk of pneumothorax. However, Arcand et al showed similar surgical
anaesthesia for both this approaches2.
The advantages of infraclavicular brachial plexus block are that it is less discomforting for the
patients as they do not require positioning of arm and there is less incidence of pneumothorax with
this approach3.
When compared with axillary brachial plexus block, the infraclavicular block has potential
advantages as it is a better type of anaesthesia for arm tourniquets and it has a higher incidence of
sussessful musculocutaneous nerve block.
Levobupivacaine, the 5-enatomer of bupivacaine, is the latest local anaesthetic agent introduced into
clinical practice. It is less cardiotoxic compared to racemic bupivacaine4. Ropivacaine, the 5-
enatomer of S-1-propyl-2,6-pipecoloxylidide, is an amino-amide local anaesthetic with chemical
structure similar to that of bupivacaine. Ropivacaine has shown to produce less cardiac and central
nervous system toxic effects, less motor block and similar duration of sensory analgesia as compared
to bupivacaine5.
The only study that has compared Levobupivacaine and Ropivacaine in infraclavicular brachial
plexus block for upper limb surgery shows that sensory block duration with Levobupivacaine is
longer then that of Ropivacaine6.
OBJECTIVE
To compare 30mL of 0.5% Ropivacaine and 30mL of 0.5% Levobupivacaine in terms of onset of
sensory block, motor block and effectiveness of analgesia for infraclavicular brachial plexus block
for below elbow surgery.
MATERIALS AND METHODS
After approval by the departmental dissertation committee and the hospital’s ethics committee, this
prospective, randomized, double blinded study was conducted.
Sample of sixty patients was taken as this was of sufficient power to show a significant difference of
2 minutes between the two groups of drugs as shown from a previous study.
Inclusion criteria was ASA Class 1 or 2 physical status, between the ages of 18 and 65 years, not
premedicated and undergoing below elbow surgery. Exclusion criteria were patient refusal, known
allergies to local anaesthetic use, coagulopathy, infection at the site of insertion, as well as patients
with peripheral neuropathy and patients with body mass index >35.
Informed consent was obtained from all patients. Patients were counseled and taught to use the pain
score.Patients were not premedicated. Patients were randomly divided into two groups, which was
either Group I, who were to receive 30mL 0.5% Ropivacaine or Group II, who were to receive 30mL
of 0.5% Levobupivacaine.
The procedure was done by a single operator. The randomization involved the use of sealed
envelopes. A sealed envelope was randomly selected and opened by an assistant, with instructions to
draw up the relevant drug. The syringe was labeled with the patients name and it was handed to the
investigator. Independent blinded observer noted the onset of sensory and motor blockade.
Patient received standard anaesthetic monitoring with an ECG monitor, pulse oximeter and non
invasive blood pressure monitor. An intravenous cannula was inserted into the opposite arm.
Baseline haemodynamics was charted. Preparations were as for general anaesthesia and resuscitation
drugs were prepared.
The patient was placed in a supine position with the head facing away from the side of the block.
The anatomy landmarks were identified based on the coracoid technique. The coracoid process was
located and the needle entry point was 2 centimeters medial and 2 centimeters caudal to the most
prominent part of the coracoid process. A marker pen was used to place “x” at the point of needle
insertion.
After appropriate skin preparation, local anaesthetic was infiltrated at the needle insertion site. A 22
gauge 100milimeters insulated beveled needle (stimuplex) was used. The needle was introduced
vertically at the landmark and a current of 2miliamperes with a frequency of 2 Hertz was set
initially. As the nerve was approached, movement of the wrist or fingers were elicited and the
current was gradually reduced to 0.4miliamperes. End point taken as presence of hand twitch at a
current of 0.4miliamperes.
Once this was achieved, the local anaesthetic was given in 5mL increments, aspirating before each
bolus to avoid intravascular injection. Patient was monitored closely after completing the block.
Patients was assessed on loss of sensation to pin prick using a three points scale (0=normal
sensation, 1=reduced sensation, 2=absent) over C5-T1 dermatomes every 2 minutes for the first 20
minutes and every 5 minutes thereafter till 30 minutes. The onset of motor block was evaluated
based on the Modified Bromage Scale (0=no paralysis, 1=wrist flexion, 2=elbow flexion,
3=complete block).
Block was considered to have failed when sensory anaesthesia was not achieved within 30 minutes
and general anaesthesia would be given. These patients were excluded from analysis. Any
complications such as pneumothorax, hematoma, tinnitus, cirumoral numbness, dizziness and
seizures was noted and documented. Instructions were given to the ward nurses to document the pain
score using (100mm) Visual Analogue Score and charted at 6 hours. The first dose of analgesia was
given after 6 hours.
Surgical incision was allowed to begin after 30 minutes when analgesia has been established. Pain
score was assessed every 30 minutes during surgery. If the pain score exceeded 20mm, then rescue
analgesia in the form of 0.5mg/kg fentanyl would be given. This would be repeated within 10
minutes interval to a maximum of two times, after which the patient was converted to general
anaesthesia.
A student t-test was used for statistical analysis of mean onset of sensory block, motor block and
effectiveness of analgesia between Group I and Group II respectively. A p value of <0.05 was
considered significant.
RESULTS
Patients’ demographic characteristics, site and duration of surgery were detailed in Table I. There
were no significant differences between both groups with respect to the above parameters.
There was a significant difference in the onset of sensory and motor block as shown in Table II and
III. Levobupivacaine group (11.1 ± 2.6) had a shorter duration of sensory and motor block
compared to Ropivacaine group (13.5 ± 2.9). There was no significant difference in the severity of
pain at 6 hours of surgery between both the groups as shown in by Table IV.
The block failure rate was relatively higher in the Levobupivacaine group (20%) as compared to the
Ropivacaine group (6.7%). There was only one notable complication which was hematoma at the
site of the insertion in the Ropivacaine group.
TABLE 1 : Demographic characteristics, site and duration of surgery.
Values expressed in mean ± standard deviation (SD) and number.
Group I
(n=28)
Group II
(n=24)
Age (years) 33.89 ± 12.39 32.88 ± 13.3
Gender (male/female) 23/5 19/5
Race (Malay/Chinese/Indian/others) 10/9/3/6 11/5/5/3
Weight (kg) 65.7 ± 11.3 65.3 ± 11.0
Site of surgery (below wrist /
forearm)
7/21 9/15
Duration of surgery (minute) 107.6 ± 31.8 109.1 ± 38.2
TABLE II : Duration required for the onset of sensory block.
Values expressed as mean ± standard deviation (SD).
Group I
(n=28)
Group II
(n=24)
Onset (minute) 13.5 ± 2.9 11.1 ± 2.6
p < 0.05
(95% confidence interval of the difference : 11.57 to 13.24)
TABLE III : Duration required for the onset of motor block.
Values expressed as mean ± standard deviation (SD).
Group I
(n=28)
Group II
(n=24)
Onset (minutes) 19.0 ± 2.7 17.1 ± 2.6
p < 0.05
(95% confidence interval of the difference : 17.37 to 18.82)
TABLE IV : Severity of pain at 6 hours of surgery.
Group I
(n=28)
Group II
(n=24)
VAS ≤ 20 VAS ≥ 30 VAS ≤ 20 VAS ≥ 30
6 hr 18 10 17 7
p > 0.05
DISCUSSION
Regional anaesthesia is useful in surgeries involving the limbs. The advantages of regional
anaesthesia over general anaesthesia are numerous and have been clearly established. These include
excellent perioperative (pre-, intra and post-operative) analgesia that can be extended into the post
operative period by utilizing continuous regional technique, avoidance of opiod-related side-effects
(particularly nausea, vomiting
and sedation) , avoidance of airway instrumentation, decrease in post-operative intensity of care,
decrease recovery time and improved patient satisfaction.
Lobat in 1922, first described the infraclavicular approach to the brachial plexus sheath, in order to
accomplish regional anaesthesia in forearm and hand surgery7. After numerous modification of this
technique, it is safe and easy to perform with high success rate in upper extremity surgeries.
An important clinical consideration is the ability of local anaesthetics to cause a differential inhibitor
of sensory and motor activity. Ropivacaine, a long acting local anaesthetic, has been reported to be
less toxic than bupivacaine. In vitro studies have demonstrated that Ropivacaine is a potent blocker
of Aδ ,C fibres (pain fibres)8. However, with the emergence of Levobupivacaine, the S-enantiomer
of bupivacaine, which has less cardiac and neural toxicity than bupivacaine, the controversy exists
on which is the ideal agent of choice for neural blockade.
C. Piangatelli et al compared 0.5% Levobupivacaine to 0.75% Ropivacaine in the infraclavicular
brachial plexuses block, which showed that the onset time for motor block was greater for the
Ropivacaine group and the sensitive block was longer for Ropivacaine group6.
The onset of sensory and motor block is related to the physicochemical properties of the individual
drug. It depends on few factors, namely the mass of the injected local anaesthetic (mass =
concentration X volume), the pKa of the drug, pH of the tissues, presence of frequency dependent
blockade. Theoretically, Ropivacaine may cause a high degree of sensory block, or at least faster
than that of motor nerve fibres compared with bupivacaine9. However, Andrea et al study
demonstrated 30mLs of 0.5% Levobupivacaine produces an interscalene brachial plexus block of
similar onset and quality as the one produced by the same volume of 0.5% Ropivacaine10. Similar
findings also reported by Lisanantti et al, who compared the use of high dose bupivacaine,
Levobupivacaine or Ropivacaine for axillary brachial plexus block, showed no statistical difference
in the quality of sensory block between the drugs at 5 minutes, 15 minutes and 30 minutes after
injection9. However, it was observed that Ropivacaine produced slightly better intensity of sensory
and motor block than that of the same dose of Levobupivacaine9.
Hickey et al compared 0.25% Ropivacaine and 0.25% bupivacaine for brachial plexus block for
upper limb surgery, which showed that although motor onset was quicker in the bupivacaine group,
there was no significant differences in terms of onset of sensory block11. However, the concentration
of local anaesthetic used in that study resulted in the need for frequent supplementation.
In a study done by Cline E et al comparing 0.5% Levobupivacaine and 0.5% Ropivacaine in patients
undergoing axillary brachial plexus block, showed that Ropivacaine group had lightly higher verbal
numerous rating scale (VNRS) scores at the 8th and 10th post operative hours5. However, in this study
the VAS score for both the groups were nearly similar. Both the groups of patients experienced mild
to moderate pain after 6 hours of the block given. Thus, there were no statistical differences noted in
regards to severity of the pain.
A limitation of this study was that the duration of the block was not assessed. However, previous
studies showed that Levobupivacaine had a longer duration of sensory block compared to
Ropivacaine for infraclavicular brachial plexus block.
CONCLUSION
There was a statistical difference in terms of onset of sensory and motor block when 0.5%
Levobupivacaine is used when compared to 0.5% Ropivacaine for infraclavicular brachial plexus
block for below elbow surgery. However, there was no difference in terms of effectiveness of
analgesia 6 hours post operatively between both the drugs.
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