A comparison of intrathecal dexmedetomidine, clonidine, and fentanyl as adjuvants to hyperbaric bupivacaine for lower limb surgery: A double blind controlled study.

BACKGROUND: Various adjuvants are being used with local anesthetics for prolongation of intraoperative and postoperative analgesia. Dexmedetomidine, the highly selective 2 adrenergic agonist is a new neuraxial adjuvant gaining popularity. SETTINGS AND DESIGN: The study was conducted in prospective, double blind manner. It included 120 American Society of Anesthesiology (ASA) class I and II patients undergoing lower limb surgery under spinal anesthesia after approval from hospital ethics committee with written and informed consent of patients. MATERIALS AND METHODS: The patients were randomly allocated into four groups (30 patients each). Group BS received 12.5 mg hyperbaric bupivacaine with normal saline, group BF received 12.5 mg bupivacaine with 25 g fentanyl, group BC received 12.5 mg of bupivacaine supplemented 30 g clonidine, and group BD received 12.5 mg bupivacaine plus 5 g dexmedetomidine. The onset time to reach peak sensory and motor level, the regression time of sensory and motor block, hemodynamic changes, and side effects were recorded. RESULTS: Patients in Group BD had significantly longer sensory and motor block times than patients in Groups BC, BF, and BS with Groups BC and BF having comparable duration of sensory and motor block. The mean time of two segment sensory block regression was 147 ± 21 min in Group BD, 117 ± 22 in Group BC, 119 ± 23 in Group BF, and 102 ± 17 in Group BS (P > 0.0001). The regression time of motor block to reach modified Bromage zero (0) was 275 ± 25, 199 ± 26, 196 ± 27, 161 ± 20 in Group BD, BC, BF, and BS, respectively (P > 0.0001). The onset times to reach T8 dermatome and modified Bromage 3 motor block were not significantly different between the groups. Dexmedetomidine group showed significantly less and delayed requirement of rescue analgesic. CONCLUSIONS: Intrathecal dexmedetomidine is associated with prolonged motor and sensory block, hemodynamic stability, and reduced demand of rescue analgesics in 24 h as compared to clonidine, fentanyl, or lone bupivacaine.

Comparative Analysis of the Efficacy of Intrathecal Fentanyl and Magnesium Sulphate as an Adjuvant to Bupivacaine: A Double-Blinded Randomized Controlled Trial.

BACKGROUNDS: The duration and potency of the subarachnoid block (SAB) can be enhanced by incorporating spinal additives into local anesthetics. In this study, the effectiveness of intrathecal fentanyl and magnesium sulphate as adjuvant anesthetics to 0.5% hyperbaric bupivacaine is compared in regard to the onset and duration of sensory and motor block, along with circulatory variables. METHODS: After authorization of ethical committee , 100 patients belonging to American Society of Anesthesiologists grades I and II, were chosen and split into two groups with 50 patients each. A SAB was administered; Group 1 was given 2.5 mL of 0.5% hyperbaric bupivacaine + 0.5 mL of fentanyl (25 µg), and Group 2 received 2.5 mL of 0.5% hyperbaric bupivacaine + 0.2 mL of magnesium sulphate (100 mg). 0.3 mL of distilled water was added to both groups making an intrathecal drug volume of 3.0 mL. Perioperative circulatory parameters and sensory and motor block features are noted and compared. Version 21.0 of Statistical Package for the Social for Windows was used for all statistical calculations. RESULTS: Group 1 had a faster onset of sensory and motor block in comparison to Group 2. However, both groups were statistically similar with regard to the duration of sensory and motor blockade, visual analog scale scores, intra and postoperative hemodynamic parameters. CONCLUSION: 0.5 mL fentanyl functions as a better spinal adjuvant to 0.5% hyperbaric bupivacaine compared to magnesium sulphate, block but both the agents had similar duration of block, postoperative analgesia and hemodynamic parameters.

Efficacy of premixed versus succedent administration of fentanyl and bupivacaine in subarachnoid block for lower limb surgeries: A randomised control trial.

BACKGROUND AND AIMS: Subarachnoid block is the most commonly used anaesthesia technique for lower limb surgeries. Opioids are the most commonly used adjuvants with local anesthetics (LA). Adjuvants are given premixed with LA loaded in a single syringe. This study was conducted to evaluate differences in level of sensory and motor block and incidence of hypotension whilst administering hyperbaric bupivacaine and fentanyl either in a single syringe or different syringes. The effect of administering opioid prior to LA and vice versa on these parameters was also assessed. METHODS: One hundred and twenty patients were randomly allocated into three groups of 40 each: Group A received premixed 0.5% heavy bupivacaine 2.5 ml (12.5 mg) and 0.5 ml (25 microgram) of fentanyl in a single 3.0 ml syringe, Group B received 0.5 ml (25 microgram) of fentanyl in a 3.0 ml syringe followed by 0.5% heavy bupivacaine 2.5 ml (12.5 mg) in a 3.0 ml syringe, Group C received 0.5% heavy bupivacaine 2.5 ml (12.5 mg) in a 3.0 ml syringe followed by 0.5 ml (25 microgram) fentanyl in a 3.0 ml syringe. All statistical calculations were done using SPSS 21 version statistical program for Microsoft Windows. RESULTS: The mean time for onset of sensory and motor block was least in group C followed by group B. The duration of sensory and motor block was prolonged in groups B and C. Patients in group A experienced more hypotension as compared to groups B and C. CONCLUSION: Administering hyperbaric bupivacaine first followed by fentanyl leads to an early onset and prolonged duration of sensory and motor block.