The Effect Of Dexmedetomidine On Early Postoperative Cognitive Function After Spinal Surgery In Elderly Patients

Objective: The main idea of this study is to explore the effects on hemodynamics, the amount of narcotic drugs, stress response,and its impact on early postoperative cognitive function after applying dexmedetomidine in spinal surgery in elderly patients,and provide a theoretical basis for clinical. Methods : 60 patients aged 65 years to 85 years underwent spinal surgery were randomly assigned into the dexmedetomidine group(group A, n=30) and control group(group B, n=30). Group A: a loading dose of dexmedetomidine(0.6μg / kg) was infused for 15 min before anesthesia induction, and then continued at a rate of 0.5μg / kg·h till 30 min before the end of surgery. Group B: given an equal volume of saline.The operations were performed under the general anethesia with endotracheal intubation. Induction of anesthesia: intravenous midazolam, sufentanil, propofol, rocuronium. Maintenance of anethesia: According to the need of the anesthesia,increase sufentanil at a moderate amount, TCI propofol effect-site concentration 2 ~ 4μg / ml, and intermittent intravenous rocuronium to maintain muscle relaxant. The intraoperative bispectral index was maintained at 40~ 60.Note the operation time, blood loss, urine output and fluid volume. It is estimated to stop pumping dexmedetomidine 30 min before the end of the operation.During surgery sewn leather, stop pumping propofol.Send the patients to the recovery room after pulling out of endotracheal intubation, and send the patients to the sickroom after one hour ’ monitor the patient’s vital signs stable.Outcome measures(1) vital signs: record blood pressure, heart rate, oxygen saturation in the T1(before given the dexmedetomidine), T2(15 minutes after given the dexmedetomidine), T3(intubation), T4(beginning of surgery), T5(the start of the surgery for 1 hour), T6(extubation).(2) the relevant circumstances surgery: surgery time, anesthesia time and the usage of intraoperative drug.(3) postoperative cognitive function assessment: perform the patient neuropsychological tests using simple intelligent evaluation method MMSE score one day before surgery and postoperative 1,3,5 day, observe the incidence of POCD.(4) messure the serum cortisol concentrations: before induction of anesthesia(C1),5min after intubation(C2), the start of surgery(C3), 30 min after start the surgery(C4), 2h after finishing the surgery(C5),postoperative day(C6).(5) Other indicators: Record the complications of postoperative nausea and vomiting, irritability, pain, and intraoperative awareness and the incidence of other adverse reactions. Results:1. Comparing two groups of patients’ general condition before surgery and during operation, the difference was not statistically significant(P> 0.05). 2. Two groups of patients before using the DEX mean arterial pressure and heart rate had no statistical significance(P>0.05), but in between T3, T4, T6 time points in two groups of patients with mean arterial pressure groups are different, with statistical significance(P<0.05); in the T2, T3, T4, T6 time point between the two groups heart rate comparison between groups differences, with statistical significance(P<0.05).3. The comparision of the dosages of sufentanil and propofol between two groups of patients, A group was significantly less than that in group B, the difference was statistically significant(P <0.05). 4. The rate of cognitive dysfunction in Group B was 26.7%, the rate of cognitive dysfunction in group A was 3.3%. The occurrence of cognitive dysfunction in Group B is higher than in group A,the difference was statistically significant(P <0.05). 5. The cort concentrations are different between the two groups were statistically significant differences(p <0.05) and within groups. The two groups cort concentrations began to increase in C3, to decline began in C5, the ascensional range in group A is smaller than in group B. 6. The comparisions of the related adverse reactions of the two groups both were not statistically significant(P> 0.05): such as hypoxemia, arrhythmia, nausea and vomiting, delayed recovery, etc; the number of postoperative agitation cases occurred in patients, A group was significantly less than in group B, with a statistically significant(P <0.05). Conclusions:1. The application of dexmedetomidine in spinal surgery in elderly patients can fully calm,maintain the hemodynamic stability,it also can reduce the incidence of postoperative agitation and the perioperative adverse reactions.2. The application of dexmedetomidine in spinal surgery in elderly patients can significantly reduce intraoperative anesthesia drug propofol and sufentanil dosage.3. The application of dexmedetomidine in spinal surgery in elderly patients can reduce the stress response.4. The application of dexmedetomidinein spinal surgery in elderly patients can reduce the early postoperative cognitive dysfunction incidences.