Cardioprotective Effect Of Dexmedetomidine In Elderly Patients Undergoing Laparoscope Assisted Radical Surgery For Colorectal Cancer

Objective(s):To prove there was a risk of myocardial injury in perioperative period of non-cardiac surgery in elderly patients,and then to demonstrate that dexmedetomidine had cardioprotection and hemodynamic stabilization effect in elderly patients undergoing laparoscopic surgery.Methods:Forty elderly patients,undergoing radical operation of colorectal cancer,aged 60-80 years,ASA ?-?,were randomly divided into Control group(group C)and Dexmedetomidine group(group D)(n=20);After receiving ECG monitoring,oxygen inhalation,opening venous access,and finishing radial arterial blood pressure monitoring,all patients underwent general anesthesia with tracheal intubation.Ten minutes before anesthesia,in the Group C,equal normal saline was infused instead of dexmedetomidine,in the Group D,dexmedetomidine was administrated intravenously with a bolus infusing at 0.5ug/kg for 10 minutes before anesthesia induction,after which,tracheal intubation was guided by a laryngoscope and central venous line was established;Surgery was maintained under intravenous-inhalation compound anesthesia.Group D was maintained pumping dexmedetomidine at 0.5ug/kg/h during the operation until 0.5 hour before the end of the surgery while Group C was maintained pumping saline.The patients were sent to the PACU for extubation after the surgery.At the time of the pre-anesthesia(TO),tracheal intubation(T1),pneumoperitoneum(T2),1.5 hours in surgery(T3),end of surgery(T4),and tracheal extubation(T5)),out of PACU(T6),the blood pressure,heart rate,and rate pressure product(RPP)were recorded,as well as the total amount of atropine,ephedrine,and phenylephrine used during the operation.Postoperative sedation and irritability score were recorded when patents were extubated in PACU.At the time of pre-induction(TO),end of surgery(T4),postoperative 24 hours(T7),postoperative 48 hours(T8),venous blood sample was collected for detection of hypersensitive troponin T(hs-cTnT)and N-terminal pro-B-type natriuretic peptide(NT-proBNP);hospitalization stay,hospitalization total cost were recorded,Patients' 30-days mortality after surgery was followed up by telephone.Results:In the experiment,the dexmedetomidine group(group D)had lower systolic blood pressure,heart rate,and rate pressure product(RPP)than the control group(group C);There were no statistically significant differences in the usage of ephedrine and atropine in group D compared with group C,but the usage amount of phenylephrine was less,and the difference was statistically significant;Compared with group C,group D had lower agitation score and higher sedation score during extubation.In the detection of myocardial injury marker hypersensitive troponin-T(hs-cTnT)and N-terminal pro-B-type natriuretic peptide(NT-proBNP),there were no statistically significant differences between group D and group C at the time of preoperation(TO)and end of surgery(T4),but the time 24 hours after operation(T7),48 hours post operation(T8),the hs-cTnT and NT-proBNP content were lower in group D,and the difference were statistically significant.There were no significantly differences in postoperative hospital stay,hospital costs and postoperative 30-day mortality.Conclusion(s):Laparoscopic radical surgery of colorectal cancer can cause elevated hypersensitive troponin and N-terminal pro-B-type natriuretic peptide in elderly patients,and there is a risk of myocardial injury in perioperative period.Dexmedetomidine has cardioprotective effect in non-cardiac surgery by stabilizing hemodynamics,mitigating perioperative stress and reducing myocardial oxygen consumption.