Effect Of Dexmedetomidine On Sleep And Cognitive Function In Post-operative Elder Patients On Mechanical Ventilation

Objective:1.To evaluate the effect of dexmedetomidine on sleep and the incidence of delirium and cognitive function in elderly patients undergoing short-term mechanical ventilation(MV)after elective operation.2.To compare the effects of dexmedetomidine and midazolam on short-term and long-term sleep quality and cognitive function in elderly patients with mechanical ventilation after operation.Methods:60 elderly patients on MV and postoperative of colorectal cancer were randomly divided into the dexmedetomidine group(Group Dex)and midazolam group(Group Mi),each group has 30 cases.All patients were provided intravenously continually for analgesia.The Group Dex was pumped dexmedetomidine at a dose of 1.0 μg / kg / h for 10 minutes,and then were given fixed 0.2~1.0 μg/(kg·h)continuous infusion.Group Mi were given 0.02~0.10 mg/(kg·h)midazolam continuous infusion.Two groups were adjusted the dosage of sedative drugs according to maintain the Richmond agitation sedation score(RASS)﹣ 2~0,and maintain BIS value 65~85.The 8 hours of electroencephalogram(EEG)was recorded in the first night from 22:00 to the next day6:00 by PSG polysomnography.And recorded the number of adverse events(unplanned extubation,cardiovascular events,respiratory depression events)during the mechanical ventilation of the two groups.The incidence of delirium in two groups was evaluated by the confusion assessment method for the ICU(CAM-ICU)in the following 7 days.Statistics of the two groups of patients with mechanical ventilation time,extubation time,keep the ICU time,and total hospitalization time.We evaluated the Mini-Mental Status Examination(MMSE)scores at 1 day before operation(T1)and 1,3,7 and 14 days after surgery(T2,T3,T4,T5).Tracked patients 90 days of sleep quality and cognitive function by Pittsburgh sleep quality index(PSQI)and MMSE.Results:1.Compared with group M,the sleep efficiency,N3%TST,REM%TST were significantly increased(t=0.04~3.44,P<0.05)and N1%TST,NREM%TST and arousal index(/h)were significantly decreased in Group Dex(t=﹣2.83~﹣3.73,P<0.05),and no significant differences were found in N2%TST between the two groups(P > 0.05).2.The delirium occurred within 7 days after surgery,Group Dex were significantly lower than Group Mi(?2 =4.283,P<0.05),The overall rate of delirium in both groups was25% within 7 days.3.There was no significant difference in the incidence of adverse events between the two groups(?2 = 0.116,P >0.05).4.The mechanical ventilation time、extubation time、retention of ICU time of Group Dex were significantly less than Group Mi(t=-0.63~-1.81,P<0.05),but there was no significant difference in the total hospital stay time(P>0.05).5.The effects of two kinds of sedative drugs and the 5time points on the cognitive function were significantly differents(F=7.41,180.79,P<0.05).Compared with Dex group,the MMSE score in group M decreased significantly at T2(t=2.63,P<0.05)and increased slowly at T3、T4(t=4.21,3.77,P<0.05).The MMSE score in Dex group had been increased to preoperative level at T4(P>0.05),but the M group recovered to the preoperative level at T5(P>0.05).The MMSE scores of T2,T3 and T4 were significantly higher in the Group Dex than those in the Mi group(t=2.63~4.21,P<0.05).There was no significant difference in MMSE scores between the two groups at T5(P>0.05).6.Group Dex were significantly less than the Group Mi at T2 and T4 of the number of postoperative cognitive function decreased and the ratio(?2=﹣ 4.28,﹣ 7.80,P < 0.05).And there were no significant differences between the two groups at T3 and T5(P>0.05).7.There was no significant difference in MMSE score and PSQI between the two groups at the 90 day after operation(t=0.58,0.71,P>0.05).Conclusions:1.Given the elderly postoperative patients who undergoing short-term mechanical ventilation dexmedetomidine or midazolam to maintain light sedation,dexmedetomidine induced high sleep efficiency,decreased awakening,induced more rapid eye movement sleep(REM),deep sleep(N3)than midazolam,the sleep structure is relatively close to natural sleep than midazolam.2.Dexmedetomidine reduce the risk of delirium in elderly patients then midazolam.And dexmedetomidine reduced the mechanical ventilation time,extubation time,and the ICU keep time than midazolam.3.So dexmedetomidine may be as an ideal choice of sedation for the elderly postoperative undergoing short-term mechanical ventilation.