Effects Of Permissive Hypercapnia On Cerebral Oxygen And Short-term Postoperative Cognitive Function In Carotid Endar Terectomy Surgery

ObjectiveTo observe the effect of permissible hypercapnia(PHC)on cerebral oxygen and short-term postoperative cognitive function in patients undergoing carotid endarterectomy(CEA),and explore the safety and feasibility of its application in such operations.Subjects and MethodsSixty patients with selective unilateral CEA were randomly divided into p ermissive hypercapnia group(H Group)and conventional ventilation group(R group),with 30 cases in each group.Mechanical ventilation of tracheal intuba tion after routine anesthesia induction in both groups,the parameters of mech anical ventilation in Group R were as follows:tidal volume(VT)8～10 ml/kg,respiratory rate(RR)12～16 beats/min,PaCO2 35～45 mmHg(1 mmHg=0.133kPa).In group H,VT was 6～8 ml/kg,RR was 12～14 times/min,PaCO2 was 46～55 mmHg.The Systolic Blood Pressure(SBP),Diastolic Blood Pressu re(DBP),Mean Arterial Pressure(MAP),heart rate(HR),Saturation of pulse oxi metry(SpO2),End-tidal carbon dioxide partial pressure(PETCO2),BIS and rSO2 value of surgical side were recorded before anesthesia(T0),5 min after trache al intubation(T1),Immediately after carotid artery occlusion(T2),Immediately after carotid opening(T3),at the end of operation(T4),blood gas analysis was performed to record the PaCO2 values at each time point,and the basic indic ators such asoperation time,carotid artery occlusion time,extubation time,PAC U stay time and fluid volume were recorded.At preoperative,24 h,48 h,3d and 7d after operation,the postoperative cognitive function was evaluated by Mini-Mental State Examination(MMSE)score.ResultsThere was no significant difference in age,weight and preoperative MMSE score between the two groups(P>0.05).MAP,HR and BIS of the two groups at each time point had no significant difference(P>0.05).There was no significant difference in operation time,carotid artery occlusion time,blood loss,infusion volume and urine volume between the two groups(P>0.05).There was no significant difference in extubation time and PACU stay time between the two groups(P>0.05).Compared with Group R,PETCO2 and rSO2 increased at T2、T3、T4 in group H,and MMSE score at 24h and 48h after operation were significantly higher in group H than in Group R(P<0.05).Compared with T0,T1、T2、T3、T4 HR and T1、T3、T4 MAP of the two groups decreased,the difference was statistically significant(P<0.05);the rSO2 at T1、T2、T3、T4 time point was decreased,the difference was statistically significant(P<0.05);compared with preoperative,the MMSE score at 24 h and 48 h after operation was decreased,the difference was statistically significant(P<0.05).ConclusionPHC can improve cerebral oxygen metabolism and short-term cognitive function in CEA operation.It is safe and feasible to apply this kind of operation.