Effect of addition of clonidine or fentanyl to intrathecal 0.75% hyperbaric ropivacaine in lower limb surgeries:- A randomized controlled clinical study.

To compare the effects of Fentanyl and Clonidine as adjuvant to  0.75% hyperbaric Ropivacaine on duration of intrathecal block .

Objective:-Primary

1.     To determine the duration of sensory and motor block.

2.     To determine time of 1st rescue analgesia.

Secondary

1.     To determine Onset of sensory and motor block.

2.     To determine Haemodynamic changes.

3.     To determine Side effects if any.

Group allocation-The patients undergoing elective lower limbsurgeries will be divided   into one ofthe two groups of 40 each

Group-RF (40)-2.5ml of 0.75% hyperbaric ropivacaine + 25 mcgfentanyl (0.5 ml) =total volume 3.0 ml Group-RC (40)-2.5ml of 0.75% hyperbaricropivacaine + 15 mcg clonidine (0.1 ml)+ 0.4 ml normal saline= total volume 3.0ml.

Study drug will be prepared by first anaesthesiologist in asterile unlabelled syringe according to group allocation. Under all asepticprecautions, lumbar puncture will be performed in L2–L3/L3–L4 inter vertebralspace in sitting position using a 25G Quincke’s spinal needle and study drugwill be injected by the second anaesthesiologist who will remain blinded tocomposition of drug.. Time of intrathecal injection will be noted. ContinuousMonitoring of the BP, HR, SpO2, and ECG will be done.

Sensory block will be assessed by the loss of sensation topinprick using a 25G blunt needle along the mid-axillary line bilaterally every2 min till two consecutive readings remain the same i.e., highest cephaladspread of sensory block has occurred. The time of sensory block at T12 will benoted as onset of sensory block and the surgeon will be allowed to start thesurgery. Regression of sensory block till S1 will be noted as duration ofsensory block. Time of 1st rescue analgesia will be determined from the time ofonset of sensory block till patient demands the first rescue analgesic and/ orVAS > 3 in post-anaesthesia care unit. Visual Analogue Scale (VAS) is used,wherein 0=no pain, and 10=severe pain every 15 minutes in the post anaestheiacare unit. Rescue analgesia will be given with Inj. Diclofenac 75 mg ivinfision.

Motor block will be assessed according to Bromage scalei.e., Bromage 0: Patients able to move hip, knee, and ankle, Bromage 1:Patients unable to move hip but able to move the knee and ankle, Bromage 2:Patient unable to move hip and knee but able to move the ankle, Bromage 3:Patient unable to move hip, knee, and ankle. Motor block will be accessed every2 minute interval. Onset of maximum motor block is defined as the time fromintrathecal injection of the drug to attain Bromage scale 3. Duration of motorblock is defined as the time taken from the onset of motor block to completerecovery of motor block i.e. Bromage score of 0. Complications such ashypotension, bradycardia, nausea, vomiting, shivering, pruritus if any, in theintra-operative as well as postoperative period will be noted in a preparedProforma and will be managed accordingly.

Following parameters will be observed:

1. Demographic parameters: Age, gender, weight, height, BMI and duration of surgery.

2. Study parameters

1.     Onset of sensory block: Time from intrathecal injection to sensory loss at T12.

2.     Duration of sensory block: Time from onset of sensory block to regression at S1.

3.     Time of administration of first rescue analgesia: Time from onset of sensory block to demand of first analgesia and/ or VAS > 3 in PACU/Ward.

4.     Onset of motor block: Time from intrathecal injection till Bromage scale 3.

5.     Duration of motor block: Time from onset of motor block to complete recovery i.e. Bromage 0.

6.     Incidence of hemodynamic changes such as hypotension, bradycardia and other side effects.