Efficacy of Dexmedetomidine as an Adjuvant to Bupivacaine in Peripheral Nerve Block - Three Prospective Randomized Controlled Studies

Abstract Introduction Peripheral nerve blocks are frequently used as the sole anesthetic technique or as an adjuvant to general anesthesia, However, the duration of sensory nerve block after single doses of long-acting local anesthetics is not consistent enough to avoid the use of postoperative opioids. Many adjuvants have been added to prolong the duration of nerve block, It was recently suggested that, based on current evidence, perineural dexmedetomidine is the most promising adjuvant to extend the duration of long-acting local anesthetics Aim The aim of this work is to study the effects of dexmedetomidine as an adjuvant to bupivacaine in various peripheral nerve blocks. The study will include: supraclavicular brachial plexus block, paravertebral block and femoral nerve block. Patients Adult patients of either sex aged 25 – 60 years, ASA physical status I and II, Elective surgeries appropriate for the nerve block. Methods patients received bupivacaine 0.5% alone in (group I) or bupivacaine 0.5% combined with 100 dexmedetomidine (group II) in peripheral nerve blocks. Motor and sensory block onset times; durations of blockades and analgesia were recorded Results Sensory and motor block onset times were shorter in group II than in group I. Sensory and motor blockade durations were longer in group II than in group I. Duration of analgesia was longer in group II than in group I. Systolic, diastolic arterial blood pressure levels, and heart rate were less in group II. Conclusion In the current study, it was obvious that:(Addition of dexmedetomidine to bupivacaine in supraclavicular nerve block, paravertebral nerve block and femoral nerve block has shortened the onset times of both sensory and motor blocks and significantly prolonged their durations, Dexmedetomidine had also the added effect of sedation with minimal side effects, which makes it a beneficial adjuvant to local anesthetics in peripheral nerve blocks, Addition of dexmedetomidine to bupivacaine prolonged the postoperative analgesia with subsequent consumption of less amount of analgesics and The use of ultrasonography in performing nerve blocks significantly reduced the incidence of complications such as pneumothorax or intra-arterial injection and hence, lowered the incidence of systemic toxicity of local anesthetics).