Comparison of Premixed Hyperbaric Bupivacaine (0.5%) and Fentanyl via Single Syringe with Sequential Administration via Two Syringes in Spinal Anaesthesia for Lower Limb Orthopedic Surgeries

Background: Subarachnoid block is one of the most commonly used anaesthesia technique for lower limb surgeries. As adjuvants opioids are the most commonly used with Local Anesthetics (LA). Adjuvants are given premixed with LA loaded in a single syringe. This study was carried out to compare 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 abovementioned parameters were also assessed. Material and Methods: A study was performed in 100 ASA class I & II patients aged between 18-60 years, undergoing lower limb elective surgeries under spinal anaesthesia. Onset of sensory and motor block, duration of analgesia, hemodynamic stability parameters. Results: The frequency of hypotension was significantly lower in Group S compared to Group M (P < 0.05). Time till the onset of sensory block was non-significantly shorter with non-significantly higher mean level of maximal sensory block in Group S compared to Group M (P > 0.05). There was no significant difference in the time till occurrence of hypotension, duration of hypotension; mean dose of Mephentermine used for the treatment of hypotension and frequency of patients developed itching in-between the groups (P > 0.05). Conclusion: Separate syringe intrathecal injection of hyperbaric bupivacaine and Fentanyl provided a tangible improvement in the quality of sensory block and significant reduction in episodes of hypotension as compared to injection of premixed medications. Administering hyperbaric bupivacaine first followed by fentanyl leads to an early onset and prolonged duration of sensory and motor blockade.