A comparative study of dexmedetomidine versus clonidine as adjuvant to intrathecal 0.5 percent hyperbaric levobupivacaine in infraumbilical surgeries

AIM: The aim of this study is to compare the effects, safety and efficacy of 5 mcg of dexmedetomidine with 30 mcg of clonidine when added to intrathecal 0.5% hyperbaric levobupivacaine in infraumblical surgeries. OBJECTIVES:

(a) To determine the time to onset and duration of sensory and motor block

(b) To determine the quality of intraoperative anaesthesia.

(c) To determine the time taken for first rescue analgesia.

(d) To determine adverse effects.

(e) To determine changes in hemodynamic parameters intraoperatively and postoperatively

Method:

100 patients of American Society of Anaesthesiologists – physical status I and II will be randomly divided into groups C and D.

GROUP C: Patients in this group(n=50) will receive intrathecal 15 mg (3 ml) of 0.5% Hyperbaric Levobupivacaine with 30 mcg (0.2ml) of Inj. Clonidine.

GROUP D: Patients in this group(n=50) will receive intrathecal 15 mg (3 ml) of 0.5% Hyperbaric Levobupivacaine with 5 mcg (diluted to 0.2ml) of Inj. Dexmedetomidine.

Patients shall undergo randomization by odd numbers and even numbers.

For odd numbers, Clonidine shall be the adjuvant to 0.5% hyperbaric levobupivacaine (group C). For even numbers, Dexmedetomidine shall be the adjuvant to 0.5% hyperbaric levobupivacaine(group D).

ANAESTHETIC PROCEDURE :

Anaesthesia machine is checked before starting the procedure.

Availability of working laryngoscope, endotracheal tubes of various sizes, other airway equipments will be ensured.

Availability of essential and emergency drugs will be ensured.

Following the arrival of patient in the pre anesthetic room, intravenous access will be established with appropriate IV Cannula and patient will be preloaded with crystalloids(15ml/kg) before giving sub arachnoid block.

Standard ASA monitoring will be used throughout the procedure with the help of a multi paramonitor (Electrocardiograpy(ECG), pulse oximetry(SpO2), temperature, NonInvasive Blood Pressure (NIBP).

Baseline vitals (HR, BP, RR, SPO2) will be recorded.

Patients will be placed in sitting or lateral position. Under strict aseptic precautions, lumbar puncture will be performed in L2/L3 or L3/L4 interspace using 25 G Quincke - Babcock spinal needle following local infiltration with 2 ml of Inj. Lignocaine 2%.

Correct placement of the spinal needle is identified by clear, free flow of the cerebrospinal fluid (CSF).

The study drug will then be injected into the subarachnoid space according to group allocation as 3 ml of 0.5% hyperbaric bupivacaine (15 mg) with 0.2 ml (30 mcg) of Inj. Clonidine in group C and 3 ml of 0.5% hyperbaric levobupivacaine (15 mg) with 5 mcg (diluted to 0.2 ml) of Inj. Dexmedetomidine in group D.

After injecting the drug, patient is placed in supine position.

Sensory block : Sensory blockade achieved will be tested by the loss of pain & temperature sensation.

The time to reach T10 level will be recorded.

Time to Peak Sensory block with the level attained will be recorded.

Time to regress upto S1 dermatomal level will be recorded.

Duration of sensory block will be documented.

Motor block : Time to achieve complete motor block (Bromage 3) and Time to regress (to Bromage 0) will be recorded.

Motor blockade is assessed using modified Bromage scale:

Bromage 0 – able to move hip, knee and ankle

Bromage 1 – able to move knee and ankle

Bromage 2 – able to move ankle only

Bromage 3 – unable to move

INTRAOPERATIVE SEDATION: Sedation is assessed by Ramsay sedation scale:

1 - anxious and agitated/restless/both

2 - cooperative, oriented and calm

3 - responsive to commands only

4 - exhibiting brisk response to light glabellar tap or loud auditory stimulus

5 - exhibiting sluggish response to light glabellar tap or loud auditory stimulus

6 - unresponsive

Quality of intaoperative anaesthesia will be noted as excellent or good or poor

Quality of analgesia will be assessed by VAS: 0 – no pain 1–3 – mild pain 4–6 – moderate pain 7–10 – severe pain.

Time of first rescue analgesic will be noted

Adverse effects will be watched for, monitored and managed meticulously

Hemodynamic parameters - blood pressure, Heart rate, respiratory rate, oxygen saturation in pulse oximetry and mean arterial pressure will be noted at base line and specific intervals intraoperatively and postoperatively