Following approval from the Institutional Ethical Committee,
informed consent will be taken from 60 patients satisfying the inclusion
criteria and they will be randomly allocated by single blinding technique into
2 groups namely Group L (0.5% Hyperbaric Levobupivacaine) and Group R (0.75%
Hyperbaric Ropivacaine).
Total number
of patients will be 60, with 30 patients in each group.
1. Group L (n=30) will receive 0.5% Hyperbaric Levobupivacaine injected
intrathecally.
2. Group R (n=30) will receive 0.75% Hyperbaric Ropivacaine injected
intrathecally.
Procedure:
All patients will be admitted before the surgery and pre anaesthetic
evaluation will be done. Fasting of 6 hours for solids and 2 hours for clear
liquids will be ensured.
After obtaining written informed consent, patients of ASA I–II of either
gender, undergoing lower limb orthopaedic surgery in whom spinal anesthesia is
indicated, will be included in the study. Patients with
contraindication to spinal anaesthesia, allergy to local anaesthetics, spinal
deformities, bleeding disorders and ASA III and above
will not be included.
On the day of surgery Intravenous (IV) access will be secured. In the
operation theater standard monitoring devices will be attached, including
noninvasive arterial blood pressure, ECG, and oxygen saturation probe and
baseline readings will be recorded.
With the patient in sitting position, lumbar puncture will be performed
with the midline approach at the L2-L3 or L3-4 interspace using 25G Quinke’s
Spinal Needle. Correct needle positioning will be confirmed with free flow of
cerebrospinal fluid and 3 ml of study drug will be injected intrathecally
slowly (injection speed: 0.2mL/sec) without further aspiration maneuvers. The
patient will be turned to supine position immediately after the injection, the
time of which is defined as ‘zero’. Patient will receive IV Inj. Ondansetron
4mg and Inj. Midazolam 1mg.
Thereafter,
the investigator will assess the following.
Sensory blockade-
·
Sensory blockade onset time
·
Maximum height of sensory block
·
Sensory blockade regression time
·
Total sensory block duration
Motor blockade
·
Motor blockade onset time
·
Motor blockade regression time
·
Total motor blockade duration
Sensory
block will be assessed by analgesia to pinprick in anterior axillary line every
minute till sensory block is achieved at T10. The sensory block starting time will
be taken as the time taken for the block to reach T10. The sensory block will
be assessed every 5 minutes till the maximum height of sensory block is
achieved and will be recorded. 2 segment regression time i.e the time taken for
the sensory block to regress 2 segments from the maximum height attained will
be noted and taken as sensory block regression time.
The
degree of motor block will be assessed using modified Bromage scale
Motor block onset time will be time when
Bromage Scale 3 occurred and motor block regression time will be when return to
Bromage Scale 1 occurs. Total duration of motor block is the period between
these 2 times.
The
heart rate and arterial pressure and peripheral oxygen saturation will be
recorded at time 0 and then at 5 min intervals for the first 30 mins and then
every 10 mins till end of surgery.
Assessments
of sensory and motor block will be continued at 30 min intervals thereafter
until complete motor and sensory blocks regression.
Hypotension
(20% or more decrease in mean arterial blood pressure [MAP] from the baseline
value) will be treated with boluses of IV Mephentermine (6 mg) and crystalloid
infusion until the normotensive state is achieved. Bradycardia (20% or more
decrease in heart rate [HR] from the baseline value) will be treated with 0.6
mg IV atropine.
In
the post operative period, the first time the patient complains of pain at the
operated site will be recorded and this will be taken as time of end of sensory
block. The time duration between onset of block at T10 and the feeling of first
post operative pain will be taken as total duration of sensory block.
Patient will be observed for any side effects such as nausea and
vomiting in the post operative period. |