Background: Bupivacaine is a long-acting local anesthetic. Addition of epinephrine is thus rarely required. It blocks initiation and transmission of nerve impulses at the site of application by stabilizing the neuronal membrane.
Objectives: To study effectiveness of 0.5% Bupivacaine for sensory blockade as local anesthesia in epidural and spinal Phase.
Methodology: After obtaining local ethical committee approval and informed consent a total number of 60 patient posted for orthopedic lower limb surgery, under combined spinal epidural were included in the study. They were divided into three groups of twenty patients each randomly. All cases were of the ASA I and ASA II in the age group of 18 to 60 years and randomly grouped in to A, B and C each including 20 cases. Group A: Epidural top up with 10 ml bupivacaine 0.5%, Group B: Epidural top up with 10 ml saline. Group C: served as a control and received no injection epidurally, but epidural injection was simulated by manipulating the epidural catheter. ANOVA test used for statistical analysis.
Results: The physical characteristics such as age, height, weight were found to be comparable in all the three groups. Statistically significant rise in sensory blockade was noticed, following administration of epidural drugs [in Group A and Group B] significant higher in group A as compared to those in group. Also it was found that time taken to achieve maximum level of sensory blockade after epidural top-up in group A was greater than that of group B which was found to be statistically significant.
Conclusion: The extension of sensory blockaded induced by an epidural top-up with a local anesthetic in CSF appears to be effected by a dual mechanism. The initial rapid increase was caused by a combination of volume effect and local anesthetic itself. The local anesthetic acts over a longer period of time which explains the prolonged but less rapid increase in level of sensory blockade in the later stages.
Keywords: Bupivacaine, Local Anesthesia, Epidural Phase
