Effect of Adding Dexmedetomidine to 0.5% Bupivacaine on Scalp Block on Intraoperative Hemodynamics During the First Hour of Surgery and Anesthetic Requirement in Intracranial Surgery

Objective Dexmedetomidine has been used as a perineural local anesthetic (LA) adjunct to improve the quality of block and decrease opioid consumption. This study aims to determine the efficacy of adding dexmedetomidine to 0.5% bupivacaine on scalp block on hemodynamic responses during the first hour of surgery, intraoperative propofol and fentanyl doses, and analgesic requirements in the first 24 hours post-craniotomy. Methods A prospective randomized controlled trial was conducted in forty-seven elective craniotomy patients receiving a scalp block with either 1 mcg/kg of dexmedetomidine (group D) or normal saline (group C) added to 0.5% bupivacaine (20 mL in total). Intraoperative blood pressure and heart rate at baseline and at 22 other time points during the first hour following the skin incision as well as the amount of intraoperative propofol and fentanyl and postoperative tramadol doses during the first 24 hours were collected and analyzed. The student t-test was used to compare means between groups, while repeated measure ANOVA with Bonferroni correction was used for comparing repeated means within each group. P-value less than 0.05 was considered statistically significant. Results During skull pin fixation (T4), the mean arterial pressure (MAP) and heart rate (HR) of both groups increased from baseline, but there were no statistically significant differences between groups. During the first hour of the operation (T7–T22), both groups had lower MAPs than their baselines, and group D had lower MAPs than group C at all time points. Intraoperative doses of fentanyl (mcg/kg) and propofol (mg/kg) in group D were significantly lower than those in group C, p = 0.027 and p = 0.030, respectively. Conclusions The addition of 1 mcg/kg dexmedetomidine tends to enhance the efficacy of scalp block with 0.5% bupivacaine in attenuating intraoperative hemodynamic responses during the first hour of surgery and reducing intraoperative fentanyl and propofol requirements during intracranial surgery. Keywords scalp block, dexmedetomidine, bupivacaine, hemodynamic response