10: Efficacy of premixed versus sequential administration of fentanyl and bupivacaine in subarachnoid block for lower limb tibial surgeries: A randomised double blind clinical Study

BACKGROUND AND AIMS: Opioids are most commonly used as adjuvants in subarachnoid block. The drug and its mode of administration affects the various block characteristics. Intrathecal administration of bupivacaine and fentanyl as premixed is compared to sequential administration in two separate syringes. METHODS: Total eighty patients were randomly allocated into two groups of 40 each: Group M (Mixed) received premixed 0.5% heavy bupivacaine 2.5 ml (12.5 mg) and 0.5 ml (25µg ) of fentanyl in a single 5.0 ml syringe, Group S (Sequential) received 0.5 ml (25 microgram) of fentanyl in a 2.0 ml syringe followed by 0.5% heavy bupivacaine 2.5 ml (12.5 mg) in a 5.0 ml syringe. Double blinding was ensured in all the cases performed. The onset and duration of sensory and motor blockade and haemodynamic parameters were observed. Data analysis was done using MedCalc software. RESULTS: The mean time for onset of sensory and motor block was less in group S (P<0.0001). The duration of sensory and motor block was prolonged in group S (P<0.0001). Patients in group M experienced more hypotension as compared to group S (P<0.05). Need for rescue analgesia was less in Group S in 24 hours (P<0.05). CONCLUSION: Administering fentanyl first followed by hyperbaric bupivacaine leads to an early onset and prolonged duration of sensory and motor block and better haemodynamic stability and less need of rescue analgesia in 24 hours.