ABSTRACT
Objective To investigate the feasibility of Narcotrend-guided application of small dose of dexmedetomidine ( DEX) for sedation during combined spinal-epidural anesthesia for elderly patients. Methods Fifty cases of ASA II or Ⅲelderly patients were randomly divided into treatment group and control group (25 patients of each group). After combined spinal-epidural anesthesia, both groups received continuous intravenous infusion of DEX, at 0. 4 μg·kg-1 in 10 min, and then the rate was lowered to 0. 4 μg·kg-1 per hour. For the treatment group, infusion rate was adjusted to reach a Narcotrend Index (NTI) of 75-85, and for the control group, infusion rate was adjusted to reach an OAA/S score of level 3-4. MAP, HR, RR, SpO2 , NTI and OAA/S score were recorded at the beginning of DEX treatment ( t0 ) , 10 min ( t1 ) , 20 min ( t2 ) , 30 min ( t3 ) , and 60 min ( t4 ) after the beginning of DEX treatment, and at the end of surgery ( t5 ) . The incidence rates of adverse events including bradycardia, hypotension, low oxygenation, and respiratory depression were also recorded. The patients were followed up until 24 h after surgery to record loss of memory about the surgical events. Results In comparison with t0 , NTI and MAP of both groups significantly decreased at t1-t5(P0. 05). Follow-up at 24 h after surgery observed total amnesia in 72. 0% of DEX group patients and in 76. 0% of the control group, without significant difference (P>0. 05). Conclusion Sedating elderly patients undergoing spinal-epidural anesthesia with DEX under the guidance of Narcotrend is safe and feasible, and the patients can be sedated properly.