A COMPARATIVE STUDY OF 0.5% HYPERBARIC LEVOBUPIVACAINE AND 0.75% HYPERBARIC ROPIVACAINE FOR SPINAL ANAESTHESIA IN LOWER LIMB ORTHOPAEDIC SURGERIES

Following approval from the Institutional Ethical Committee,informed consent will be taken from 60 patients satisfying the inclusioncriteria and they will be randomly allocated by single blinding technique into2 groups namely Group L (0.5% Hyperbaric Levobupivacaine) and Group R (0.75%Hyperbaric Ropivacaine).

Total numberof patients will be 60, with 30 patients in each group.

1. Group L (n=30) will receive 0.5% Hyperbaric Levobupivacaine injectedintrathecally.

2. Group R (n=30) will receive 0.75% Hyperbaric Ropivacaine injectedintrathecally.

Procedure:

All patients will be admitted before the surgery and pre anaestheticevaluation will be done. Fasting of 6 hours for solids and 2 hours for clearliquids will be ensured.

After obtaining written informed consent, patients of ASA I–II of eithergender, undergoing lower limb orthopaedic surgery in whom spinal anesthesia isindicated, will be included in the study. Patients withcontraindication to spinal anaesthesia, allergy to local anaesthetics, spinaldeformities, bleeding disorders and ASA III and abovewill not be included.

On the day of surgery Intravenous (IV) access will be secured. In theoperation theater standard monitoring devices will be attached, includingnoninvasive arterial blood pressure, ECG, and oxygen saturation probe andbaseline readings will be recorded.

With the patient in sitting position, lumbar puncture will be performedwith the midline approach at the L2-L3 or L3-4 interspace using 25G Quinke’sSpinal Needle. Correct needle positioning will be confirmed with free flow ofcerebrospinal fluid and 3 ml of study drug will be injected intrathecallyslowly (injection speed: 0.2mL/sec) without further aspiration maneuvers. Thepatient will be turned to supine position immediately after the injection, thetime of which is defined as ‘zero’. Patient will receive IV Inj. Ondansetron4mg 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

Sensoryblock will be assessed by analgesia to pinprick in anterior axillary line everyminute till sensory block is achieved at T10. The sensory block starting time willbe taken as the time taken for the block to reach T10. The sensory block willbe assessed every 5 minutes till the maximum height of sensory block isachieved and will be recorded. 2 segment regression time i.e the time taken forthe sensory block to regress 2 segments from the maximum height attained willbe noted and taken as sensory block regression time.

Thedegree of motor block will be assessed using modified Bromage scale

Motor block onset time will be time whenBromage Scale 3 occurred and motor block regression time will be when return toBromage Scale 1 occurs. Total duration of motor block is the period betweenthese 2 times.

Theheart rate and arterial pressure and peripheral oxygen saturation will berecorded at time 0 and then at 5 min intervals for the first 30 mins and thenevery 10 mins till end of surgery.

Assessmentsof sensory and motor block will be continued at 30 min intervals thereafteruntil complete motor and sensory blocks regression.

Hypotension(20% or more decrease in mean arterial blood pressure [MAP] from the baselinevalue) will be treated with boluses of IV Mephentermine (6 mg) and crystalloidinfusion until the normotensive state is achieved. Bradycardia (20% or moredecrease in heart rate [HR] from the baseline value) will be treated with 0.6mg IV atropine.

Inthe post operative period, the first time the patient complains of pain at theoperated site will be recorded and this will be taken as time of end of sensoryblock. The time duration between onset of block at T10 and the feeling of firstpost operative pain will be taken as total duration of sensory block.

Patient will be observed for any side effects such as nausea andvomiting in the post operative period.