This study assessed the effects of low-dose subarachnoid block with bupivacaine and fentanyl in elderly hypertensive female patients undergoing vaginal hysterectomy. Sixty-two patients were randomly assigned to receive either 12.5 mg bupivacaine alone or 7.5 mg bupivacaine with 25 mg fentanyl. The combination led to a faster onset and longer duration of sensory blockade without prolonging motor blockade. It also resulted in fewer episodes of hypotension, less need for vasopressors, and longer duration of postoperative analgesia. The low-dose combination provided effective spinal anesthesia with improved hemodynamic stability and pain relief.

1. Vol. 20 No. 2, 2006
Subarachnoid Block With Low Dose Bupivacaine And
Fentanyl In Elderly Hypertensive Female Patients Undergoing
Vaginal Hysterectomy
1Dr. Lalita Gouri Mitra, 2Dr.Suman Chattopadhyay, 3Dr. B. N.Biswas, 4Dr. Manjushree Ray, 5Dr.Pinaki
Mazumder.
Summary :
A prospective randomised double blinded study was designed to assess the effect of low
dose hyperbaric bupivacaine with fentanyl in the subarachnoid space on hemodynamic stability and
duration of sensory and motor block in elderly hypertensive female patients undergoing vaginal
hysterectomy. Sixty two elderly hypertensive female patients in the age group of 60-65 years were
randomly allocated to receive intrathecally either 12.5 mg of hyperbaric bupivacaine (0.5%) (group
B) or 7.5 mg of 0.5 % hyperbaric bupivacaine with 25 mg of fentanyl (group BF). The onset and
duration of motor and sensory block, fall in blood pressure (MAP), heart rate and incidence of side
effects were noted at regular interval and compared between the two groups. Addition of fentanyl
resulted in faster onset of sensory block (3.6 ± 2.3 min in group BF v/s 6.9 ± 1.7 min in group B;
P value< 0.05) but did not enhance the onset of motor block. Group BF exhibited increased duration
of sensory block (169.36 ± 34.24 min in group BF v/s 119.73 ± 29.37 min in group B; P value
< 0.05) without prolonging the duration of motor block. Control group B experienced more episodes
of hypotension and required more mephenteramine (vasopressor agent) than group BF (41.93% v/
s 12.90%; P value < 0.05). A reduced dose of hyperbaric bupivacaine 7.5 mg in combination with
fentanyl 25 mg provides reliable subarachnoid bock for vaginal hysterectomy in elderly hypertensive
patients with few events of hypotension, little need for vasopressor support of blood pressure, and
prolonged duration of analgesia.
Keywords : Patient : Elderly, Hypertensive, Vaginal hysterectomy. Block : Subarachnoid, Bupivacaine,
Fentanyl.
1. DA, MD, DNB, MNANS Assistant Professor, Department of Anaesthesiology, Calcutta Medical College, Kolkata.
2. MD., Assistant Professor, Department of Anaesthesiology, Calcutta Medical College, Kolkata.
3. MD., Associate Professor, Department of Anaesthesiology, Calcutta Medical College, Kolkata.
4. MD., MNAMS, Professor & H.O.D, Department of Anaesthesiology, Midnapore Medical College.
5. MD., Assistant Professor, Department of Anaesthesiology, Calcutta Medical College, Kolkata.
46
Low-dose subarachnoid block has been
advocated in the interest of improving
cardiovascular stability and providing better
anaesthesia without prolonging recovery1. Current
sophistication of knowledge concerning spinal
anaesthetic technique makes cardiovascular
instability easy to prevent. The addition of various
combinations of opioids has allowed a reduction
in the dose of bupivacaine for conventional spinal
anaesthesia. This is associated with less
hypotension but has a better postoperative
outcome1-6.
Ben-David B et al6 obseved better
haemodynamic stability following subarachnoid
block with low dose bupivacaine-fentanyl
combination in elderly patients undergoing repair
for hip fracture.Therefore, the present study
was designed to assess the safety, efficacy,
perioperative haemodynamic stability along with
postoperative pain relief of low dose bupivacaine
with fentanyl, for elderly hypertensive women
undergoing vaginal hysterectomy.
Address for correspondence : Dr. Suman Chattopadhyay
BC –103, Salt Lake, Kolkata –700064. Phone no. – (033) 23587261 E-mail – sumanc_24@yahoo.co.in

2. 47
Material and Methods
After approval of hospital ethical committee
and written informed consent, 62 elderly female
patients in the age group of 60-65 years, with
a long-standing history of hypertension of at
least 5 years, were included in the study. The
blood pressure of all patients was controlled
with beta-blockers to a systolic blood pressure
of 140-150 mmHg and a diastolic blood pressure
of 90-100 mmHg. Patients who had any
contraindication to receive a subarachnoid block
and those who had higher blood pressure
preoperatively on the day of surgery were
excluded from the study.
The subjects were randomly assigned to
two groups using random number table. The
syringe was prepared by one researcher and
administered by another who remained blinded
to its contents. Patients received 12.5 mg
(2.5 ml) of 0.5% hyperbaric bupivacaine
(Group B) or 7.5 mg of 0.5% hyperbaric
bupivacaine with 25 mg of fentanyl with normal
saline (0.9%) to make a total volume of 2.5 ml
(Group BF). All patients receivedoral alprazolam
0.25 mg the night before surgery and two hours
prior to coming to the operation theatre and
also the morning dose of the beta-blocker. Before
the subarachnoid block was given, each patient
received a preload of 15 ml kg-1 of compounded
Ringer’s lactate intravenously and preprocedure
vital parameters were recorded. With the patient
in sitting position, the lumbar puncture was
performed under complete aseptic precautions,
using a 25G Quincke needle at L3-4 level. Once
free flow of clear CSF was obtained, the study
drug was administered over 10 seconds and
the patient was then made to lie supine with
slight a head up position. All patients were given
3 litres of oxygen by facemask during the
surgical procedure.
Standard monitoring of vital parameters
(pulse, BP, respiration, SpO2) was done at
2 minutes intervals, for 20 minutes, and then
every 10 minutes, until complete resolution of
motor block and feeling of normal sensation by
Dr. Lalita Gouri Mitra : Study
the patient at the feet. Sensory neural blockade
was assessed by pinprick method every
2 minute for first 20 minutes over the
dermatomes, on the mid-clavicular line bilaterally.
Motor blockade was assessed using the
modified Bromage scale7. The duration of
sensory anaesthesia was calculated from the
time of spinal injection to the time taken for two
level sensory regressions from the peak block
height. Time taken for full recovery of motor
function was also recorded.
The intensity of pain was also recorded
every 15 minutes in the post-operative period
using a VAS, which was explained to the patient
preoperatively, and graded on a scale of 1 to
10. Duration of postoperative analgesia was
measured as the time interval between the
administration of spinal block and the first
request for supplemental analgesia.
Postoperative pain was treated with tramadol
1.5 mg kg-1 intramuscularly.
For the purpose of the study, hypotension
was defined as decrease in mean blood pressure
(MBP) by 20% or more of baseline and was
managed with bolus doses of 200 ml of
compounded Ringer’s Lactate and injection
mephenteramine 3 mg intravenously.
Bradycardia was defined as a fall in heart rate
less than 20% from baseline or a heart rate
< 50 beats per minutes, and was treated with
injection atropine 0.6 mg intravenously. Total
vasopressor and intravenous fluids used were
recorded. Respiratory depression was defined
as a respiratory rate of £8 per minute or oxygen
saturation of £90%.
Adverse effects like, pruritis, nausea,
vomiting, sedation, shivering, headache and
sedation / respiratory depression were recorded.
Intraoperative nausea was treated with
intravenous ondenseterone 4 mg and pruritis
with naloxone 20-40mg iv. The presence of
urinary retention could not be assessed, as all
the patients had indwelling catheter.
Data was analysed statistically using
unpaired test, Fischer’s exact test, multiple

3. 48
comparison and multiple range tests, wherever
applicable. P value (corrected for multiple
comparisons) < 0.05 was considered significant.
Data was presented as mean values ± SD,
median (range) values, and numbers (percent).
Results
The two treatment groups (consisting 31
patients each) were comparable with respect to
ASA physical status, age, weight, height, and
the surgical duration (Table 1). The highest
sensory levels achieved were T 7 (T6-8) in both
Group B (control) and Group BF (fentanyl). Time
for onset of sensory block was 3.6 ± 2.3 min
and the duration of sensory block was 89 ±
18 min in Group BF (v/s 6.9 ± 1.7 min and
72 ± 15 min, respectively in Group B, P<0.05)
(Table 2). Neither the onset of bupivacaine
induced motor blocks nor their duration were
prolonged by the addition of fentanyl to
bupivacaine for subarachnoid block (Table 2).
More patients in Group B experienced
hypotension in comparison to in Group BF [13
(41.93%) v/s 4 (12.90%)] (Table 3, P<0.05).
The requirement of mephenteramine was higher
in Group B than in Group BF (7.5 ± 4.5 v/s 3.0
± 0 mg, P<0.05) (Table 3). Between the two
groups we found no differences in the incidence
of pruritis, shivering, nausea and bradycardia
(Table 4). No patient experienced respiratory
depression in our study. Patients in Group BF
demanded the first dose of analgesia much later
than in patients in Group B (169.36 ± 34.24 min
v/s 119.73 ± 29.37 min, P<0.05) (Table 5).
Discussion
The choice of the local anaesthetic depends
upon both duration of action and potential for
neurological injury. Bupivacaine, the best
available drug available for subarachnoid block
in India, has duration of action that is
intermediate between that of lignocaine and
tetracaine, a lower incidence of transient
radicular irritation than lignocaine, and a more
rapid and shorter duration of motor blockade
than tetracaine. Bupivacaine has a longer
duration than levobupivacaine and ropivacaine,
Vol. 20 No. 2, 2006
and a higher success rate than an identical
dose of levobupivacaine8. The most important
determinant of both successful surgical
anaesthesia and time until recovery is the dose
of local anaesthetic drug9. Using an intrathecal
opioid, reduces the period of recumbency after
spinal anaesthesia, by allowing early
ambulation, and results in decrease in the
incidence of post-dural puncture headache10 and
the duration of hospital stay.
We have chosen the dose of 25 mg of
fentanyl as most studies have shown this dose
provides maximum duration of postoperative
analgesia with minimal side effects like
respiratory depression and pruritis 11,12,13. There
was evidence of a dose response relationship
in a study by Belzarena SD14 where higher
doses were associated with increased analgesia
but with increased pruritis. In addition to minimal
side effects, the ideal intrathecal opiate should
have a rapid onset and a long duration of action,
thus providing improved intra- and postoperative
analgesia. Diamorpine 15,16 has theoretical
benefits in this regard however this drug is not
available in our country.
We evaluated the use of 7.5 mg hyperbaric
bupivacaine with 25 mg fentanyl in the
subarachnoid space and its hemodynamic
stability, duration of spinal anaesthesia, time
taken for full recovery of motor and sensory
function and the requirement for mephenteramine
in elderly hypertensive female patients.
In two different studies1,17 the use of low
dose bupivacaine (5mg) along with two different
doses of fentanyl intrathecally resulted in shorter
lasting motor block, but maintained the same
level of sensory analgesia as with larger doses
of bupivacaine (7.5 mg, 10mg) with or without
fentanyl. The level of sensory analgesia was
same in both groups in our study. Sensory
analgesia should be at least upto T6 for vaginal
hysterectomy, and we could achieve this level
both with dosage of 12.5 mg hyperbaric
bupivacaine alone and with 7.5 mg hyperbaric
bupivacaine with 25 mg fentanyl. However, the
addition of fentanyl resulted in faster onset of
sensory block (3.6 ± 2.3 min v/s 6.9 ± 1.7 min)

4. 49
and duration of sensory block was prolonged in
Group BF (89 ± 18 min v/s 72 ± 15 min).Onset
and duration of motor block was similar in both
the groups. Mahajan R et al18 found that the
level of sensory analgesia was not influenced
by intrathecal fentanyl but there was significant
prolongation of time taken for the regression of
sensory block below T12 dermatome when
fentanyl was included, though the onset and
regression of motor blockade were comparable
in both groups.
All patients in a study by Liu S et al19,
developed pruiritis, a common complication of
intra-thecal opioid use. Few patients in our study
(9.67%) in the group BF developed pruritis.
Fernandez-Galinski D et al20, found that 25 mg
of fentanyl given in the intra-thecal space,
induced hypoxia in elderly patients undergoing
hip or knee surgery, when combined with
pre and intra-operative benzodiazepines. None
of the patients in either of the two groups, in
our study developed respiratory depression, even
though all the patients were premedicated with
sustained release oral alprazolam 0.25 mg the
night before surgery and two hours prior to
coming to the operation theatre.
Fernandez-Galinski D et al20 also reported
that fewer patients who received 4 mg isobaric
bupivacaine with 20 mg of fentanyl, developed
hypotension, in comparison to patients receiving
only 10 mg isobaric bupivacaine intra-thecally.
Ramanathan et al21, have reported a modest
decrease in MAP using intrathecal 7.5 mg
bupivacaine and 25 mg fentanyl in severely
preeclamptic parturients with combined spinal-epidural
Dr. Lalita Gouri Mitra : Study
approach (15 ± 7% in caesarean delivery
and 16 ± 9% in labour analgesia. Patients in
both the groups in our study showed a fall in
MAP, within 4-7 minutes. The fall in MAP was
more significant in the Group B than in Group
BF [13 (41.93%) v/s 4 (12.90%)] and the
requirement of mephenteramine was higher in
Group B than in Group BF (7.5±4.5 v/s 3.0 ±
0 mg, P<0.05). Intrathecal fentanyl by itself and
not in combination with bupivacaine causes a
further blockade of sympathetic efferent activity
and that clinical influence after spinal
anaesthesia is related to the dose of
bupivacaine1,5,6. Fentanyl has been found to
provide greater hemodynamic stability and better
quality of analgesia as compared to isolated
use of either drug alone22.
The first dose of postoperative analgesia
was required much later in Group BF than in
patients in Group B (169.36 ± 34.24 min v/s
119.73 ± 29.37 min, P < 0.05). Higher doses of
bupivacaine reduces the occurrence of visceral
pain even though T4 sensory level has been
achieved with lesser doses23. Intrathecal fentanyl
inhibits afferent synaptic transmission via C and
A fibres, and also has direct postsynaptic effect
with hyperpolarisation and reduced neuronal
activity causing prolonged postoperative pain
relief24,25.
To conclude, addition of 25 mg of fentanyl
to 7.5 mg of hyperbaric bupivacaine provides
adequate surgical anaesthesia for vaginal
hysterectomy, stable hemodynamics, lesser
events of hypotension and need for vasopressor,
as well as a longer postoperative pain free period
in elderly hypertensive patients.
Table 1. Demographic characteristics of the two treatment group
Control(B)Mean ± S.D. Fentanyl(BF)Mean ± S.D.
Age (yrs) 62 ± 2 63 ± 2
Height (cm) 153 ± 4 151 ± 5
Weight (kg ) 55 ± 11 56 ± 15
Duration of surgery (min) 99 ± 27 101 ± 32
No statistical differences

5. Table 3 : Haemodynamic changes and incidence of hypotension
Table 4 : Incidence of side effects
Parameter CONTROL(B) FENTANYL(BF)
No. of patients (%) No. of patients (%)
Bradycardia (HR< 60bpm) 10 (32.25%) 6 (19.35%)
Itching 0 3 (9.67%)
Nausea 9(29.03%) 3(9.67%)
Respiratory depression (SaO2<90%) 0 0
Table 5 : Duration of analgesia
Parameter CONTROL(B) FENTANYL(BF)
Mean ± S.D. Mean ± S.D.
Duration of analgesia (min) 119.73 ± 29.37 169.36 ± 34.24 *
*R< 0.05
CONTROL(B) FENTANYL(BF)
Baseline systolic blood pressure (mmHg) 143.12 ± 6.20 142.67 ± 8.10
Baseline diastolic blood pressure (mmHg) 95.56 ± 5.10 94.36 ± 6.22
No. of patients having hypotension (%) 13(41.93%) 4 (12.90%)*
(MAP < 20mmHg)
Total dose of mephenteramine (mg) 7.5 ± 4.5 3 ± 0
Values are mean± SD or numbers (percent)
*P<0.05, considered significant (Fischer’s exact test)
50
Vol. 20 No. 2, 2006
Table 2. Characteristics of sensory block and motor block
Parameter CONTROL(B) FENTANYL(BF)
Highest sensory block median (range) T 7 (T6-8) T 7 (T6-8)
Onset of sensory block (min) 6.9 ± 1.7 3.6 ± 2.3 *
Duration of sensory block (min) 72 ± 15 89 ± 18*
Onset to grade 3 motor block (min) 8.9 ± 3.9 7.6 ± 2.9
Duration of grade 3 motor block (min) 109 ± 36 116 ± 27
Values are either median (range) or mean±SD *R< 0.05

6. 51
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