comparision between bupivacaine and levobupivacaine in hypertensive patients

1. Subarachnoid block with isobaric 0.5%
levobupivacaine or hyperbaric 0.5% bupivacaine in
hypertensive subjects. A prospective, randomized ,
double blind comparative study.
Dr SUDHEER KUMAR.A
DR ASHIMA SHARMA
Dr R GOPINATH

2. Introduction:
 Spinal anesthesia is an accepted technique for lower limb surgeries.
 Spinal induced hypotension is a major complication of the technique. If it is not
prevented or managed properly, cardiac arrests have been reported in literature(1).
 Hypertensive patients have a disturbed autonomic balance which presents as
increased sympathetic response , arrhythmias and cardiac ischaemias under
anesthesia(2).
 Regional anesthesia especially the subarachnoid block is a prudent choice for
provision of anesthesia for lower limb orthopaedic surgeries. A small dose of local
anesthetic deposited in the intrathecal space with an estimated time for effect to
disappear is more safer than GA.
 SIH can be significant in hypertensive patients, especially those in whom
preoperative BP are ≥ 130/90(3).

3. Back ground-
 Hyperbaric 0.5% bupivacaine is most commonly used drug for spinal anesthesia .
The drug has low CC/CNS ratio.
 Newer drugs like levobupivacaine are relatively cardiostable and have more
sensory than motor blockade.
 This should mean that spinal anesthesia with levobupivacaine will keep the
haemodynamic parameters more stable than with bupivacaine.
 Levobupivacaine is presently available as isobaric preparation in 0.5%
concentration.

4. Aim of the study-
 PRIMARY AIM-
 to compare the haemodynamic effects of subarachnoid block with either 0.5%
hyperbaric bupivacaine or 0.5% isobaric levobupivacaine in hypertensive patients
.
 SECONDARY AIMS-
 To compare block characterstics i.e., onset of sensory analgesia, maximal height
of block assessed to blunt pinprick.

5. METHODOLOGY:
 ETHICS COMMITTEE PROFORMA SUBMITTED TO IEC, Approval awaited.
 INCLUSION CRITERIA-60 patients , with known history of hypertension for
less than 5 years without any organ involvement ( ASA II) of either sex in the
age range of 40-60 years. The patient’s BP should be controlled ( ≤ 120/80)on
antihypertensive therapy ( maximum of 2).
 Patients with DM or any other disease leading to autonomic instability were
excluded from the study.
 Written informed Consent was taken from all patients.
 A thorough pre-anesthetic evaluation and relevant laboratory investigations
were obtained with detailed evaluation of CVS, Renal and CNS effects of hypertension.

6. RANDOMISATION-
 SEALED ENVELOP TECHNIQUE WITH COMPUTER ( MICROSOFT EXCEL)
GENERATED RANDOM NUMBERS.
 Each number with additional L or B was written on piece of paper and sealed in
envelop and left with the technician.
 The primary investigator loaded the drug according to the letter found .
 The secondary investigator , who was involved in statistical analysis was kept
blinded to the drug used.

7.  Sixty selected patients were divided into two equal groups of 30 patients .
 Bupivacaine Group:(group B) In this group patients were given 0.5% hyperbaric
bupivacaine 3 ml intrathecally.
 Levobupivacaine Group:(group L) In this group patients were given 0.5%
isobaric levobupivacaine 3 ml intrathecally.
 25 ugs of fentanyl was added to all spinal injectates
 Demographic characteristics, preoperative pharmacotherapy, cardiac status and
haemodynamics were compared before and after SB between the two groups.

8. Statistics:
 At the end of the study, results in the two groups were tabulated and subjected to
statistical analysis by applying Statistical Package for Social Sciences (SPSS)
version 17.1.
 The data was normally distributed among the two groups.
 The results were considered statistically significant when P-value was < 0.05.

9. TABLE2- INTERGROUP COMPARISONS FOR
INTRAOPERATIVE DATA( ANOVA applied)
PARAMETER BUPIVACAINE LEVOBUPIVACAIN
E
P VALUE
ONSET OF
SENSORY
ANALGESIA
( PARASTHESIAS)
-mins
4.5± 1.2 2.2± 0.9 0.001
HEIGHT OF
BLOCK
T 10(8-11) T6(5-9) 0.023
SBP( PREBLOCK-
POSTBLOCK)
158.08±15.84-
108.80±12.24
143.07±21.04 -
100.15±25.35
0.04
DBP( PREBLOCK-
POSTBLOCK)
90.50±18.12 -
78.60± 10.12.
87.30±18.12 -
81.60± 19 .
0.05
HR- DELTA
CHANGE %
5.14 8.77 0.04

10. DISCUSSION:
 The dose of study drugs was comparable as reported by Bouvet etal (4)
 O Vanna etal(5) have concluded equal effects in spinal anesthesia when isobaric
levobupivacaine was compared to hyperbaric bupivacaine in urological surgeries.
 In our study, block height was higher in group L which means higher autonomic
blockade.
 This can be attributed to decrease in baricity of the drug by fentanyl resulting in a
hypobaric solution and a higher block.

11. CONCLUSION:
 Isobaric levobupivacaine provides adequate SB for lower limb orthopaedic
surgeries.
 However, there is an increased possibility of higher blocks with addition of fentanyl.
 The drug should be cautiously used in hypertensive patients, where excessive
decrease in BP can disturb the autoregulation further.

12. References :
 Bouvet L. ED50 and ED 95 of intrathecal levobupivacaine with opioids for
caesarean delivery. Br J Anaesth.2011;106: 215-20.
 O Vanna, L Chumsang and S Thongmee. Levobupivacaine and Bupivacaine in
Spinal Anesthesia for Transuretheral endoscopic surgery. Journal of the Medical
association of Thailand. 2006 ; 89(8): 1133-39.