Effects of Low versus Intermediate Doses of Dexmedetomidine Infusion on Blood Loss, Hemodynamics, and Operative Time in Transsphenoidal Pituitary Tumor Removal: A Prospective Randomized Study

Abstract Background  Dexmedetomidine, an alpha-2 agonist, has been widely used as an anesthetic adjunct for transsphenoidal pituitary resection. However, there is no consensus on the appropriate infusion dosage. This study aimed to compare the effects of low (0.2 mcg/kg/h) and intermediate (0.5 mcg/kg/h) dexmedetomidine infusions during anesthetic maintenance on blood loss, hemodynamics, and operating time. Methods  A randomized controlled trial involving two centers was conducted. Between December 2015 and November 2019, 80 patients (40 in each group) who underwent elective transsphenoidal pituitary tumor resection were recruited. Dexmedetomidine was administered to group I at a loading dose of 0.5 mcg / kg, followed by 0.2 mcg / kg / h, and to group II at the same loading dose, followed by 0.5 mcg / kg / h. Comparative analyses were performed using the Student's t -test, repeated-measures analysis of variance, and Mann–Whitney U test; p -values < 0.05 were considered statistically significant. Results  Eighty patients were analyzed. Patient demographics were comparable. The difference in intraoperative blood loss between both groups (320 [220–525] vs. 250 [100-487] mL, p  = 0.070) was not statistically significant. There were no differences in blood pressure or heart rate between the groups. In group II, the procedure took significantly less time (179 vs. 142 minutes, p  = 0.018), with more episodes of transient hypotension ( p  = 0.034). Conclusion  When maintaining anesthesia for transsphenoidal pituitary resection, dexmedetomidine infusions of 0.2 and 0.5 mcg / kg / h showed the same effect on blood loss and hemodynamics; however, significantly more episodes of transient hypotension and shorter operating times were noted with the latter.