Abstract

RELATIVE POTENCIES OF MOTOR BLOCKADE AFTER INTRATHECAL ROPIVACAINE, LEVOBUPIVACAINE AND BUPIVACAINE

Author(s): V. Udayagiri Ravisankar 1 , Sugali Jyothi 2

Ever since the times spinal anaesthesia has been introduced by August Bier, multiple drugs at different dosages, concentrations and differing baricities have been studied. This study was conducted to compare the anaesthetic efficacy of intrathecal isobaric 0.5% ropivacaine, isobaric 0.5% bupivacaine and isobaric levobupivacaine in lower abdominal and lower limb surgeries, in 150 ASA grade I and II patients of both sexes in the age group of 19-65 years undergoing elective surgery under spinal anaesthesia. MATERIALS & METHODS After getting ethical committee approval and informed written consent from the patients, 150 patients were allocated into three groups of 50 patients each. The baseline pulse rate and mean arterial pressure were recorded. The first group A received 3ml of isobaric 0.5% ropivacaine (5mg/ml), the second group received 3ml of isobaric 0.5% bupivacaine and the third group C received 3ml of isobaric levobupivacaine intrathecally. The onset of sensory and motor blocks, duration of sensory and motor blocks was recorded in three groups. RESULTS The results were analyzed statistically using epidemiologically information package. On comparison of data we have found that the intrathecal isobaric 0.5% ropivacaine produces delayed onset of both sensory and motor block but of shorter duration which is statistically significant when compared with that of isobaric 0.5% bupivacaine and levobupivacaine. There is no significant inter-group difference between bupivacaine and levobupivacaine except for the mean duration of sensory block, which is more in levobupivacaine group. The quality of motor block which was assessed by Bromage scale, shows relatively lesser degree of motor block for ropivacaine group, when compared with that of bupivacaine and levobupivacaine groups. The haemodynamics were also recorded. The incidence of hypotension and Bradycardia is more in bupivacaine group. The height of block (peak sensory level) is higher for bupivacaine group followed by levobupivacaine and then ropivacaine. T4+T6% of Groups A, B& C are 5%, 48% and 44% respectively.