<p>The Effect of Different Doses of Intravenous Dexmedetomidine on the Properties of Subarachnoid Blockade: A Systematic Review and Meta-Analysis</p>

Abstract

Background Dexmedetomidine is a sedative and analgesic medication which has gained an increased usage as an adjuvant to both general and regional anaesthesia in recent years. In this systematic review and meta-analysis, we examined the changes to the characteristics of subarachnoid block when accompanied with intravenous dexmedetomidine. Our aim is to evaluate the effects of different doses of intravenous dexmedetomidine on the sensory and motor blockade duration of a single shot spinal anaesthetic and the incidence of any associated side effects. Methods We searched published randomized clinical trials (RCTs) from January 1992 to April 2019 that investigated the use of IV dexmedetomidine with spinal anaesthesia. After considering our inclusion and exclusion criteria, we included 15 RCTs with 985 patients. We analyzed the duration of sensory and motor blockade and the related adverse effects in relation to different doses of IV dexmedetomidine. Results Intravenous dexmedetomidine, with loading dose of 1 mcg/kg, prolonged the sensory blockade duration of spinal anaesthesia by a mean difference of 49.6 min, P<0.001, and motor blockade duration by a mean difference of 44.7 min, P<0.001, while a loading dose of 0.5 mcg/kg prolonged the sensory blockade by a mean difference of 43.06 min, P<0.001, and motor blockade duration by a mean difference of 29.09 min, P<0.001. Dexmedetomidine-related side effects were higher in patients receiving larger doses; the incidence of bradycardia was higher (OR=3.53, P<0.001) and incidence of hypotension showed a 1.29 fold increase when compared to the control group (P=0.065). Conclusion The administration of intravenous dexmedetomidine in conjunction with spinal anaesthesia can significantly prolong the duration of both sensory and motor blockade. The use of larger loading doses of dexmedetomidine was associated with a larger side-effect profile with minimal beneficial changes when compared to lower loading doses.

Response to Letter to the Editor Appeared in ( Khan and Karim Ain-Shams Journal of Anesthesiology (2023) 15:78 https://doi.org/10.1186/s42077-023-00378-8)

“…This cost will be over and above the cost of analgesic drug which will be used in any case after 20-40 min in such scenerio. [4,5,6] The adverse effects observed with the use of these drugs in our study were statistically insignificant, as also reported by Jaung et al in their metaanalysis of 14 studies. [7] The most common reported adverse effects in other studies are bradycardia and hypotension but usually these were mainly related to its intravenous use as infusion in the elderly and in patients with pre-existent cardiac disease.…”

“…This cost will be over and above the cost of analgesic drug which will be used in any case after 20-40 min in such scenerio. [2,3,4]…”

Dexmedetomidine versus dexamethasone as adjunct to ropivacaine in erector spinae plane block for patients undergoing breast surgery: a randomized, prospective, double blinded study

“…23,24 Studies have reported good analgesic effect with this dose range, although few studies reported bradycardia, hypotension and sedation with dose of 1-2 mcg/kg. 25,26 So we stick to the dose of 0.5 mcg/kg which resulted in good postoperative analgesia with median VAS of 2. None of the patients in our study had bradycardia, hypotension or sedation in the intraoperative or postoperative period.…”

Dexamethasone versus Dexmedetomidine as Adjuvant to Bupivacaine in Ultrasound Guided Erector Spinae Plane Block for Analgesia in Total Abdominal Hysterectomy

“…Using Dexmedetomidine in ESPB decreased VAS and analgesic consumption in the postoperative period when compared to plain ropivacaine without any adjunct (10) . Few studies reported bradycardia, hypotension and sedation with dose of 1-2 mcg/kg (11) .…”