Effect of Fentanyl and Dexmedetomidine as Additives to 0.5% Ropivacaine in Ultrasound Guided Supraclavicular Brachial Plexus Block for Elective Upper Limb Surgeries: A Randomised Clinical Trial

Introduction: Supraclavicular brachial plexus block is a superior alternative to general anaesthesia for upper limb surgeries, and use of ultrasound makes it safe and efficient in implementation. Ropivacaine, having significantly higher threshold for cardiotoxicity and neurotoxicity and more potent blocker of A and C fibres, renders good sensory blockade and lesser motor. Hence, to overcome this, additives are added. Aim: To evaluate the block characteristics with addition of either fentanyl or dexmedetomidine to 0.5% ropivacaine for supraclavicular brachial block. Materials and Methods: This randomised double-blinded clinical trial, was conducted on 50 patients posted for upper limb surgeries under supraclavicular brachial plexus block were randomly allocated to either receive 30 mL of 0.5% ropivacaine with 50g fentanyl (Group RF) or 30 mL of 0.5% ropivacaine with 50g dexmedetomidine (Group RD).The time for onset of sensory block and motor block were noted. Intraoperative hemodynamics were monitored in all the patients. Postoperatively Visual Analog Scale (VAS) scoring for pain, the time for rescue analgesia and the duration of sensory and motor blockade were noted. Results: Both groups were comparable with respect to age, gender and American Society of Anaesthesiologists (ASA) grading. The onset of both sensory (p-value 0.008) and motor block (p-value 0.0005) was faster in Group RD compared to Group RF which was highly significant statistically. The duration of sensory (p-value 0.0005) and motor block (p-value 0.0005) was longer in Group RD compared to Group RF which was highly significant statistically. The requirement for rescue analgesia was lesser in Group RD since the mean VAS score was persistently low which was statistically significant (p-value <0.01) compared to Group RF. Conclusion: The blockade improved better with addition of dexmedetomidine than fentanyl to 0.5% ropivacaine. There were no increased incidence for side effects.