Comparison of Efficacy of 0.5% Hyperbaric Bupivacaine and 0.75%Isobaric Ropivacaine for Spinal Anaeshesia

Overview

Spinal anaesthesia is a preferred technique used for lower abdominal and lower limb surgeries as it provides faster and profound sensory and motor blockade. Bupivacaine is the most commonly used local anaesthetic in spinal anaesthesia. Earlier studies have suggested that Ropivacaine causes shorter duration of motor blockade and provides early ambulation to the patient. The aim of this double- blinded, prospective, randomized controlled study was to compare the effect of 0.5% Hyperbaric Bupivacaine and 0.75% Isobaric Ropivacaine for spinal anaesthesia.

Regional anaesthesia is a well established anaesthetic technique to provide anaesthesia for lower abdominal and lower limb surgeries.Spinal anaesthesia is one of the regional anaesthesia techniques where local anaesthesia is injected into lumbar subarachnoid space to anaesthetize nerves that exit the spinal cord. Spinal anaesthesia is most commonly used for anaesthesia and analgesia for a variety of lower extremity, abdominal, pelvic and perineal procedures. Spinal anaesthesia is widely used by anaesthesiologists due to many advantages like quick onset, dense anaesthesia with minimal side effects compared to general anaesthesia. It has become popular because of the simplicity, less operative blood loss, and minimal preoperative preparation. Motor block from spinal anaesthesia beyond the duration of surgery is undesirable. So, spinal anaesthesia is not preferred in ambulatory settings. Various local anaesthetics have been used for spinal anaesthesia, starting with cocaine way back in 1898. Hyperbaric Bupivacaine is a commonly used drug for spinal anaesthesia. The acute and most severe adverse effects of local anaesthetics are cardiovascular and CNS toxicity. These are usually because of accidental intravascular injection and pronounced overdose. These adverse effects have prompted a search for drugs with lesser toxicity. This led to the introduction of newer local anaesthetics like Ropivacaine. Ropivacaine, the S - enantiomer of Propivacaine is less lipophilic than Bupivacaine. This property is associated with a decreased potential for CNS toxicity and cardiotoxicity. Hence, it has a better safety profile. Ropivacaine is similar to Bupivacaine in onset, quality, duration of sensory block and it produces lesser duration of motor blockade. Ropivacaine has shown to be effective and comparable haemodynamic effect in spinal anaesthesia compared to Bupivacaine in lower abdominal and lower limb surgeries. Ropivacaine may be useful in day care surgeries and in surgeries where early ambulation is required for the patients. In the past, Lignocaine was used for spinal anaesthesia. However, it was associated with transient neurological symptoms and became less popular. Both Bupivacaine and Ropivacaine are being used in surgeries like transurethral replacement of prostate, lower abdominal and lower limb surgeries,cesarean section, hip and knee replacement surgery. There are very few studies comparing intrathecal use of equal volume of Isobaric Ropivacaine and Hyperbaric Bupivacaine and comparing their efficacy and duration of motor blockade.