Effect Of Dexmedetomidine On Postoperative Cognitive Function In Elderly Patients Undergoing Long-term Operation

Objective:To observe the effect of dexmedetomidine on cognitive function and postoperative rehabilitation in elderly patients after long-term operation.Methods:a prospective,randomized,double-blind,controlled clinical study method was used to select 47 elderly patients（age>65 years old）who were to undergo selective laparoscopic radical surgery for colorectal cancer from February to October in our hospital.They were randomly divided into control group（Group C,n=25）and experimental group（Group D,n=22）.Both groups were given combined intravenous and inhalation general anesthesia,in which group D was given 0.5 ug/kg/h of dexmedetomidine after anesthesia induction Group C received the same amount of saline after induction.ECG,BP,SpO₂,HR,IAP and BIS were monitored.Midazolam 0.05-0.1 mg/kg,propofol 1.5-2.0 mg/kg,cisatracurium benzene sulfonate 0.15-0.2 mg/kg,sufentanil 0.3 ug/kg were used for anesthesia induction.Respiratory control was performed after tracheal intubation.Remifentanil 0.1-0.5 ug/kg/min was used for pump injection,sevoflurane（1%-2%）was inhaled,cisatracurium benzene sulfonate 4-6 mg/kg.The BIS value was between 40 and60.The mean arterial pressure（map）and heart rate（HR）were recorded at 8 time points:entering the room（T₀）,immediately after induction（T₁）,immediately after intubation（T₂）,30 minutes after induction（T₃）,at skin incision（T₄）,at 3 hours after operation（T₅）,at the end of operation（T₆）and at the time of extubation（T₇）.The general condition,operation time,anesthesia time,intraoperative bleeding volume,recovery time and postoperative adverse reactions of the two groups were recorded.The cognitive function of the two groups was measured by Newman’s modified neuropsychological test combination on the first day before operation and the seventh day after operation.Results:compared with group C,the map and HR of group D were significantly lower from T₄ to T₇（p<0.05）.There was no significant difference in operative time,intraoperative bleeding volume and recovery time between the two groups（p>0.05）.There was no significant difference in the preoperative neuropsychological test scores between the two groups（p>0.05）.The postoperative scores of the two groups were lower than that before the operation.The incidence of cognitive dysfunction in group D was significantly lower than that in group C（p<0.05）.Conclusion:Injected with dexmedetomidine in elderly patients undergoing radical resection of colorectal cancer can play a protective role in postoperative cognitive function and reduce the incidence of cognitive dysfunction,it has less influence on patients’hemodynamics index,less adverse reaction after operation,and has better clinical and prognosis effect.It can be widely used in clinic.