Background and Aims:Mixing adjuvants with hyperbaric bupivacaine in a single syringe before injecting the drugs intrathecally is an age old practice. In doing so, the density of the hyperbaric solution and also of the adjuvant drugs may be altered, thus affecting the spread of drugs. Administering local anaesthetic and the adjuvants separately may minimise the effect of the changes in densities. We aimed to compare block characteristics, intraoperative haemodynamics and post-operative pain relief in parturients undergoing caesarean section (CS) after administering hyperbaric bupivacaine and clonidine intrathecally as a mixture and sequentially.Methods:In this single-blind prospective randomised controlled study at a tertiary care centre from 2010 to 12, 60 full-term parturients scheduled for elective CSs were divided into two groups on the basis of technique of intrathecal drug administration. Group M received mixture of clonidine (75 mcg) and hyperbaric bupivacaine 0.5% (10 mg) intrathecally, whereas Group B received clonidine (75 mcg) followed by hyperbaric bupivacaine 0.5% (10 mg) through separate syringes. Observational descriptive statistics, analysis of variance test, Wilcoxon test and Chi-square test were used as applicable.Results:Duration of analgesia was significantly longer in Group B (474.33 ± 20.79 min) in which the drug was given sequentially than in Group M (337 ± 18.22 min). Furthermore, the time to achieve highest sensory block and complete motor block was significantly less in Group B without any major haemodynamic instability and neonatal outcome.Conclusions:When clonidine and hyperbaric bupivacaine were administered in a sequential manner, block characteristics improved significantly compared to the administration of the mixture of the two drugs.

Background:Density of the drugs injected intrathecally is an important factor that influences spread in the cerebrospinal fluid. Mixing adjuvants with local anesthetics (LA) alters their density and hence their spread compared to when given sequentially in seperate syringes.Aims:To evaluate the efficacy of intrathecal administration of hyperbaric bupivacaine (HB) and clonidine as a mixture and sequentially in terms of block characteristics, hemodynamics, neonatal outcome, and postoperative pain.Setting and Design:Prospective randomized single blind study at a tertiary center from 2010 to 2012.Materials and Methods:Ninety full-term parturient scheduled for elective cesarean sections were divided into three groups on the basis of technique of intrathecal drug administration. Group M received mixture of 75 μg clonidine and 10 mg HB 0.5%. Group A received 75 μg clonidine after administration of 10 mg HB 0.5% through separate syringe. Group B received 75 μg clonidine before HB 0.5% (10 mg) through separate syringe.Statistical analysis used:Observational descriptive statistics, analysis of variance with Bonferroni multiple comparison post hoc test, and Chi-square test.Results:Time to achieve complete sensory and motor block was less in group A and B in which drugs were given sequentially. Duration of analgesia lasted longer in group B (474.3 ± 20.79 min) and group A (472.50 ± 22.11 min) than in group M (337 ± 18.22 min) with clinically insignificant influence on hemodynamic parameters and sedation.Conclusion:Sequential technique reduces time to achieve complete sensory and motor block, delays block regression, and significantly prolongs the duration of analgesia. However, it did not matter much whether clonidine was administered before or after HB.

The incidence of accidental injection of local anaesthetic into the subdural space during neuraxial blockade is rare. The presentation of unexplainable clinical signs that do not match the clinical picture of subarachnoid or intravascular injection of the local anaesthetic agent should invoke high suspicion of unintentional subdural block. We report on a case of a sixmonth-old infant who developed motor block and unconsciousness with haemodynamic stability, following a caudal block for postoperative analgesia. The report will help to illustrate the mechanism behind the complication of subdural deposition of the drug, its detection, treatment and possible avoidance.