Comparison of a loading dose of dexmedetomidine combined with propofol or sevoflurane for hemodynamic changes during anesthesia maintenance: a prospective, randomized, double-blind, controlled clinical trial

Background: There may be great individual variability in the hemodynamic effects of this dexmedetomidine. For this reason, the dose must be carefully adjusted to achieve the desired clinical effect. Whether a loading dose of dexmedetomidine produces hemodynamic side effects during the anesthesia maintenance is unknown. The aim of this study was to compare the effects of a loading dose of dexmedetomidine combined with propofol or sevoflurane on hemodynamics during anesthesia maintenance. Methods: Eighty-four patients who were scheduled for general surgery under balanced general anesthesia were randomly allocated into 4 groups (n = 21): the propofol and dexmedetomidine group, the sevoflurane and dexmedetomidine group, the propofol and normal saline group, or the sevoflurane and normal saline group. The hemodynamic indexes at the time of just before, 5 min after and the end of study drug infusion (dexmedetomidine or normal saline) were recorded. The incidence rates of increasing blood pressure at the end of study drug infusion (greater than 20% compared to baseline or before study drug infusion) were evaluated. Results: Mean arterial pressure increased significantly (P < 0.01) only in the propofol and dexmedetomidine group after intravenous dexmedetomidine compared administration. 80% of cases with propofol and dexmedetomidine had increased mean arterial blood pressure compared to only 5% of cases in the sevoflurane and dexmedetomidine group (P < 0.05). Heart rates in the propofol and dexmedetomidine and the sevoflurane and dexmedetomidine groups decreased significantly after dexmedetomidine infusion (P < 0.01). Conclusions: Intraoperative administration of a loading dose of dexmedetomidine combined with propofol in anesthesia maintenance proceeded a significant increase in blood pressure. In contrast, it combines with sevoflurane didn't produce increased blood pressure. Meanwhile it is not unexpected that dexmedetomidine combined with propofol or sevofurance decreased heart rate, due to the known side effects of DEX. Therefore, dexmedetomidine should be used cautiously during the entire intravenous anesthesia maintenance period, especially during maintenance with propofol.