Impact of local administration of various doses of dexmedetomidine on ropivacaine-induced lumbar plexus-sciatic nerve block

Safety and efficacy of dexmedetomidine in combination with local anesthetics for orthopedic nerve blocks: a systematic review and meta-analysis

INTRODUCTION

Peripheral nerve block, a common technique for managing postoperative pain and providing intraoperative analgesia, often includes adjuncts like dexmedetomidine (DEX) to enhance the effectiveness of local anesthetics. DEX, known for its α2-adrenoceptor agonist properties, extends sensory blockade and improves postoperative analgesia while offering sedative benefits. The objective of this study is to rigorously assess the effectiveness and safety of perineural DEX injection in orthopedic nerve block procedures, focusing on orthopedic surgeries to minimize heterogeneity and provide clearer insights for clinical practice.

EVIDENCE ACQUISITION

This meta-analysis, registered on PROSPERO, involved a comprehensive literature search across multiple databases, focusing on RCTs comparing DEX with local anesthetics for peripheral nerve blocks in orthopedic surgery patients. The eligibility criteria included adult participants and various nerve block methods in orthopedic surgeries. Studies were rigorously appraised for methodological quality using Cochrane Handbook guidelines. GRADE profiler 3.6 was used for evidence grading.

EVIDENCE SYNTHESIS

Among 1391 documents, 21 studies were included, focusing on DEX with local anesthetics in orthopedic nerve blocks. Findings showed significant improvements in analgesia duration, sensory and motor block duration, and reduced postoperative opioid consumption, with an increased risk of bradycardia. Quality assessments indicated moderate bias risk.

CONCLUSIONS

DEX with local anesthetics significantly enhances nerve block effectiveness, extending analgesia and block durations while reducing opioid need. However, it requires careful monitoring due to increased bradycardia risk. These findings highlight the need for cautious use in clinical practice, considering both potential benefits and adverse effects.

Dexmedetomidine as an Adjuvant in Peripheral Nerve Block

Peripheral nerve block technology is important to balanced anesthesia technology. It can effectively reduce opioid usage. It is the key to enhance clinical rehabilitation as an important part of the multimodal analgesia scheme. The emergence of ultrasound technology has accelerated peripheral nerve block technology development. It can directly observe the nerve shape, surrounding tissue, and diffusion path of drugs. It can also reduce the dosage of local anesthetics by improving positioning accuracy while enhancing the block's efficacy. Dexmedetomidine is a highly selective drug α₂-adrenergic receptor agonist. Dexmedetomidine has the characteristics of sedation, analgesia, anti-anxiety, inhibition of sympathetic activity, mild respiratory inhibition, and stable hemodynamics. Numerous studies have revealed that dexmedetomidine in peripheral nerve blocks can shorten the onset time of anesthesia and prolong the time of sensory and motor nerve blocks. Although dexmedetomidine was approved by the European Drug Administration for sedation and analgesia in 2017, it has not yet been approved by the US Food and Drug Administration (FDA). It is used as a non-label drug as an adjuvant. Therefore, the risk-benefit ratio must be evaluated when using these drugs as adjuvants. This review explains the pharmacology and mechanism of dexmedetomidine, the effect of dexmedetomidine on various peripheral nerve block as an adjuvant, and compare it with other types of adjuvants. We summarized and reviewed the application progress of dexmedetomidine as an adjuvant in nerve block and look forward to its future research direction.