Double Blind, Randomised Controlled Study for Comparative Evaluation of Equal Volume of Two Different Doses of Ropivacaine Hydrochloride (0.75% and 0.5%) in Spinal Anaesthesia in Lower Limb Orthopaedic Surgery Regarding the Onset and Duration of Sensory and Motor Blockade

Abstract

BACKGROUNDCentral neuraxial blockade is a major regional anaesthesia technique with a long history of effective use for a variety of surgical procedures and pain relief. Ropivacaine is an amino-amide local anaesthetic drug, which was first synthesised in 1957 and was introduced into clinical practice in 1996. As there are limited studies on effect of ropivacaine in spinal anaesthesia, we conducted a dose comparison study of ropivacaine in our institute to know the clinical efficacy and safety with regard to better patient profile management.The aim of the study was to compare and evaluate equal volumes of two different doses of ropivacaine hydrochloride (0.75% and 0.5%) in spinal anaesthesia in lower limb orthopaedic surgeries with regard to the onset and duration of sensory and motor blockade. MATERIALS AND METHODSIt is a prospective, randomised, double-blind study conducted in a tertiary care hospital in which 80 patients of age group 20 -65 years of either sex which were scheduled to undergo lower limb orthopaedic surgeries under spinal anaesthesia with two different doses of Ropivacaine Hydrochloride were included. The patients were randomly divided into 2 groups of 40 each. Group A received 22.5 mg (3 mL) of 0.75% isobaric Ropivacaine Hydrochloride. Group B patients received 15 mg (3 mL) of 0.5% isobaric Ropivacaine Hydrochloride. RESULTSRopivacaine 0.75% produced higher level and longer duration of sensory blockade than ropivacaine 0.5% when used in spinal anaesthesia. Thus, there was longer duration of analgesia with ropivacaine 0.75%. The ropivacaine 0.75% solution resulted in higher frequency and longer duration of motor block in the lower limbs than ropivacaine 0.5%. Thus, a reliable motor blockade was obtained with ropivacaine 0.75%. Therefore, it is concluded that intrathecal ropivacaine 0.75% provides an excellent sensory blockade with longer duration of analgesia and a complete motor block, which makes it suitable for lower limb orthopaedic surgeries requiring an intense sensory and motor blockade. CONCLUSIONOur study suggests the use of ropivacaine 0.75% for spinal anaesthesia in lower limb orthopaedic surgeries, as it provides prolonged duration of sensory and profound motor blockade of lower limbs.