Comparison Of Onset And Duration Of Sensory And Motor Blockade Between Equipotent Doses Of 0.75% Plain Ropivacaine And 0.5% Plain Levobupivacaine In Lower Abdominal Surgeries Under Epidural Anaesthesia- A One Year Randomized Clinical Study

Abstract

Background and Objectives Epidural anaesthesia is being routinely practiced and has been the anaesthetic technique of choice for most of the abdominal and lower limb surgeries. Newer long-acting local anesthetics namely ropivacaine and levobupivacaine, introduced recently for clinical use claim benefits over racemic bupivacaine in the form of reduced cardiac and CNS toxicity on overdose. Hence the present study was undertaken to compare the clinical efficacy of 0.75% Ropivacaine with 0.5% Levobupivacaine for epidural anaesthesia in patients undergoing lower abdominal surgeries. Methods The present one year randomized clinical study was conducted between January 2013 to December 2013 on 90 ASA grade I and II patients of either gender, aged between 20 to 60 years who were allocated to receive either 15ml of 0.75% plain ropivacaine or 15 ml of 0.5% plain levobupivacaine epidurally for elective lower abdominal surgeries at KLES Dr. Prabhakar Kore Hospital and Medical Research Centre, Belgaum. Results The groups were statistically similar as regards demographic data and pre anaesthetic characteristics. The mean times for onset of sensory block in Group R and Group L were 17.93 ± 2.98 min and 18.62 ± 3.09 min respectively. The mean duration of sensory block in group R (196.78 ± 20.31 min) was longer than that in group L(189.56 ± 19.53 min) although the difference was statistically insignificant. (p=0.067). Two patients in group R and three patients in group L developed a sensory block level upto T6 dermatomal level. The mean onset of motor block in group R was similar to that in group L (24.09 ± 3.07 v/s 25.47 ± 4.13; p=0.076) while duration of motor blockade was observed to be shorter in group R (111.53 ± 16.70min ) as compared with group L (118.53 ± 18.14 min) though it was statistically insignificant (p=0.056). Ropivacaine provided a longer duration of post operative analgesia than levobupivacaine (263.0 ± 22.77 vs 253.78 ± 24.43 minutes) although the difference remained statistically insignificant. Conclusion and interpretation It can be concluded that both 0.75% ropivacaine(15ml) and 0.5% levobupivacaine(15ml) when administered epidurally for elective lower abdominal surgeries, provide adequate and comparable sensory and motor blockade with minimal haemodynamic disturbances. Ropivacaine results in a shorter duration of motor blockade and provides a longer duration of sensory blockade and post operative analgesia.