Comparative study of ropivacaine with ropivacaine-fentanyl and ropivacaine-fentanyl- magnesium sulfate in epidural anesthesia for lower limb surgeries

Background: Epidural anesthesia is currently one of the most used technique for patients undergoing lower limb surgery. Dose sparing action of one adjuvant for another in epidural anesthesia with local anesthetic drugs for providing quality care to the patient remains controversial. Aims of the present study was to compare and study the properties 0.75% Ropivacaine alone (R) with 0.75% Ropivacaine-Fentanyl (RF) and 0.75% Ropivacaine-Fentanyl-Magnesium sulfate (RFM) in epidural anesthesia for lower limb surgeries. Study design was prospective randomized double blind study.Methods: Patients between 18-60 years of age of ASA physical status class I and II undergoing lower limb surgeries were randomly allocated into 3 groups of 20 each. Total volume in epidural space given was 17ml in all 3 groups. Group R (n=20) received 15ml of 0.75% Ropivacaine with 2ml of normal saline, Group RF (n=20) received 15ml of 0.75% Ropivacaine with 50mg of fentanyl (1ml) and 1ml normal saline and Group RFM (n=20) received 15ml of 0.75% Ropivacaine with 50mg of fentanyl (1ml) and 100mg MgSO4 (1ml). Patients were then studied for hemodynamic profile, various block characteristics and side effects. Statistical analysis used was ANOVA, paired t-test, Chi-square and post hoc test were used. P <0.05 was considered significant.Results: All three groups had stable hemodynamic parameters with Group RFM showing better block characteristics (p <0.001) in terms of time for achieving onset of analgesia, time for achieving T10 sensory blockade, time for requirement of first epidural top up, time for achieving motor Blockade, time for complete recovery of motor blockade with no significant differences in the side effect profile.Conclusions: Epidural anesthesia for lower limb surgeries may have better block characteristic parameters if a combination of Ropivacaine-fentanyl-magnesium sulphate is used in comparison with ropivacaine-fentanyl or ropivacaine alone.