Ravi Vasupalli 1 , Prakash T. S. N
BACKGROUND Intrathecal anaesthesia and epidural anaesthesia are the most popular regional anaesthesia techniques used for lower limb surgeries. Intrathecal anaesthesia also called as subarachnoid block. It has few limitations like short duration of anaesthesia, extension of anaesthesia cannot be made for prolonged surgeries, rapid onset of sympathetic blockade, shorter duration of postoperative analgesia and troublesome complication of Post-Dural Puncture Headache (PDPH). Hence, epidural anaesthesia is the most preferred anaesthetic technique for lower limb surgeries these days. METHODS TIME FRAME The study was conducted during period spanning December 2013 to November 2014. STUDY POPULATION Patients who met all inclusion criteria were randomly selected. No distinction is made between males and females. STUDY DESIGN A prospective, randomised, double blind, case control, observational, interventional comparative study is designed after getting the informed written consent was obtained from the patient. RANDOMISATION Randomisation was done using a computer generated random number table. One hundred patients scheduled for various elective lower limb surgical procedures belonging to ASA class I and II were included in the study. 1. Group RD (n=50) 15 mL of 0.75% ropivacaine + 0.6 µg/kg of dexmedetomidine (Inj. DEXTOMID-1 mL=100 mcg, 1 mL ampoule); 2. Group RF (n=50) 15 mL of 0.75% ropivacaine (ropivacaine 0.75% preservative free-ROPIN 0.75%, 20 mL ampoules-Neon Laboratories, India), fentanyl 1 µg/kg Inj. FENTANYL-1 mL=50 mcg, 2 mL ampoule). The patients were premedicated with tablet alprazolam 0.5 mg and tablet ranitidine 150 mg orally at bedtime on the previous night before surgery. They were kept nil orally 10 p.m. onwards on the previous night. On the day of surgery, patient’s basal pulse rate and blood pressure were recorded. A peripheral intravenous line with 18 gauge cannula after local anaesthesia was secured in one of the upper limbs. All the patients were preloaded with 500 mL of Ringer lactate 30 minutes prior to the epidural procedure multi-parameter monitor was connected, which records heart rate, non-invasive measurement of Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), continuous Electrocardiogram (ECG), monitoring and Oxygen Saturation (SPO2). With the patients in sitting position for epidural anaesthesia, painting the lumbar spine with 7.5% povidone-iodine solution waited for three minutes after that cleaned with the rectified spirit after that draped with the sterile clothes. Under aseptic precautions, after infiltrating skin with the 2% Xylocaine epidural space was identified by loss of resistance technique to air using 18G Tuohy needle via the midline approach at either L2-3 or L3-4 interspinous space (whichever space was felt better). An epidural catheter was threaded and fixed at 3 cms inside the epidural space. A test dose of 3 mL of 2% lignocaine with 1:2,00,000 adrenalines was injected through the catheter after aspiration. Study drug prepared by another colleague anaesthetist who was unaware of the study according to the randomised study number generated against the patient. 15 mL volume of drug, which was a mixture of the ropivacaine 0.75% and added study drugs dexmedetomidine or fentanyl. The dosages of these drugs were 0.6 µg/kg of dexmedetomidine and 1 µg/kg of fentanyl, respectively. After ruling out intrathecal and intravascular placement of the tip of the catheter, the study drug injected in increments of 5 mL. The patients were turned to supine position immediately after giving the study drug. Sensory and motor blockade were assessed at the end of each minute with the patient in supine position after completion of the injection of the study drug. The onset time for sensory and motor block, The maximum level of sensory block, Intensity of motor block and sedation scores were recorded (Tab 1). Sensory blockade was assessed using a short bevel 22 gauge needle and was tested in the midclavicular line on the chest, trunk and lower limbs on either side. Motor blockade in the lower limbs was assessed using modified Bromage scale.[4,5].
