Determination of the effective dose of dexmedetomidine to achieve loss of consciousness during anesthesia induction

Abstract

BackgroundDexmedetomidine (DEX) is a sedative with greater preservation of cognitive function, reduced respiratory depression, and improved patient arousability. This study was designed to investigate the performance of DEX during anesthesia induction and to establish an effective DEX induction strategy, which could be valuable for multiple clinical conditions.MethodsPatients undergoing abdominal surgery were involved in this dose-finding trial. Dixon's up-and-down sequential method was employed to determine the effective dose of DEX to achieve the state of “loss of consciousness”, and an effective induction strategy was established with continuous infusion of DEX and remifentanil. The effects of DEX on hemodynamics, respiratory state, EEG, and anesthetic depth were monitored and analyzed.ResultsThrough the strategy mentioned, the depth of surgical anesthesia was successfully achieved by DEX-led anesthesia induction. The ED50 and ED95 of the initial infusion rate of DEX were 0.115 and 0.200 μg/kg/min, respectively, and the mean induction time was 18.3 min. The ED50 and ED95 of DEX to achieve the state of “loss of consciousness” were 2.899 (95% CI: 2.703–3.115) and 5.001 (95% CI: 4.544–5.700) μg/kg, respectively. The mean PSI on the loss of consciousness was 42.8 among the patients. During anesthesia induction, the hemodynamics including BP and HR were stable, and the EEG monitor showed decreased α and β powers and increased θ and δ in the frontal and pre-frontal cortices of the brain.ConclusionThis study indicated that continuous infusion of combined DEX and remifentanil could be an effective strategy for anesthesia induction. The EEG during the induction was similar to the physiological sleep process.

The feasibility of dexmedetomidine-led anesthesia maintenance strategy during major abdominal surgery

“…Patients’ characteristics during dexmedetomidine-led anesthesia induction and maintenance are recorded ( Table 3 ). The induction dose of dexmedetomidine was 3.1 (3, 3.4) μg/kg, which was consistent with our previous study [ 9 ]. The duration of surgery was 3.1 ± 0.7 h and the duration of anesthesia was 3.6 ± 0.7 h dexmedetomidine, remifentanil and rocuronium were used for anesthesia maintenance, and their doses during anesthesia (include induction and maintenance) were 3.23 ± 0.76 μg/kg·h, 12.99 ± 2.79 μg/kg·h and 0.44 ± 0.08 mg/kg·h respectively.…”

“…Previous study showed that dexmedetomidine at plasma concentrations of 0.37 ng/ml and 0.69 ng/ml reduced isoflurane MAC by 35% and 47%, respectively [ 19 ]. Our previous study showed that dexmedetomidine-led strategy could accomplish anesthesia induction [ 9 ]. This study showed that dexmedetomidine-led strategy also ensured effective anesthesia maintenance and adequate depth during abdominal surgery.…”

“…Anesthesia induction was started with intravenous 3 μg/kg sufentanil. 30 s later, dexmedetomidine (Yangtze River Pharmaceutical Group Co. Ltd, Jiangsu, China) and remifentanil were continuous infused (Silugao CP-730 TCI pump, Silugao Med Tech, Beijing, China), this dexmedetomidine-led anesthesia induction has been described in our study [ 9 ]. After sufficient depth of anesthesia was achieved (Observer's Assessment of Alertness/Sedation Scale = 1, Supplementary Table 1 ), 0.8 mg/kg rocuronium was infused, intubation was performed.…”

“…Commonly used anesthetics, such as sevoflurane and propofol, have been reported to induce neurogenesis alteration and apoptosis, reduce proliferation of neural stem cells [ 7 , 8 ], and affect postoperative cognitive function. Our study showed that dexmedetomidine-led induction strategy could achieve the depth of stage III (surgical stage) anesthesia [ 9 ]. Therefore, dexmedetomidine-led strategy could also be feasible in anesthesia maintenance and provide advantages in cognitive function protection and postoperative recovery, especially for elderly or critically ill patients with cognitive impairment.…”