The Effect Of Permissive Hypercapnia On Postoperative Cognitive Function And Serum S100? Protein In Elderly Patients Undergoing Laparoscopic Surgery

Objective:The purpose of this paper was to study the effect of permissive hypercapnia on postoperative cognitive funtion and serum s100? protein in elderly patients undergoing laparoscopic surgery.Methods:We enrolled 80 patients between the ages of 65~75,ASA I~III,body mass index(BMI)between 18 kg/m2 and 30.0 kg/m2,undergoing gastrointestinal laparoscopic surgery,patients were divided into regular group(R group,40 cases)& permissive hypercapnia group(H group,40 cases)randomly.All the patients used the same way of anesthesia induction and maintenance.After anesthesia induction,the mechanical ventilation was adjusted by Pa CO2 and p H value,maintaining Pa CO2 and p H value between 45~55mm Hg & 7.25~7.35 in H group,which were maintained 35~45 mm Hg& 7.35~7.45 in R group.The blood pressure,heart rate,blood gas analysis and s100?,IL-6 concentration were recorded at T1(before anesthesia induction),T2(end anaesthesia),T3(1 day afer operation),T4(2 days afer operation),T5(7 days afer operation).Serum samples s100? and IL-6 protein levels each patient were determined by enzyme-linked immunosorbent assay.The MMSE score was obtained on 1 day before operation and1,2 and 7 days after operation.Result:(1)There were no significance difference in age,body weight,the period of pneumoperitoneum,anesthesia duration time and extubation time between R group and H group patients(P>0.05).(2)At 2 days after surgery,12(16%)patients experienced POCD,4(10.5%)in H group and 8(21.6%)in R group(10.5% VS.21.6%,P<0.05).At 7 days after surgery,5(6.7%)patients experienced POCD,2(6.7%)in H group and 3(8.1%)in R group(6.7% VS.8.1%,P>0.05).2 days after operation,the occurrence rates of POCD in groups H were significantly lower than the groups R(P<0.05),the difference disappeared 7 days after operation.(3)Serum s100? and IL-6 level was increased significantly at T3,T4 in both two group compare with preoperation(P<0.05),but there was no significantly difference in serum s100? and IL-6 level between H group and R group preoperation as well as7 days after operation(P>0.05).(4)Patients who exhibited cognitive dysfunction had higher s100? levels at day1 and day 2 postoperative compared to those who did not(P=0.01,P=0.02,respectively).Conclusion:(1)Maintaining permissive hypercapnia during operation may decrease the occurrence rate of POCD in gerontal patients.(2)While undertaking gastrointestinal laparoscopic surgery under permissive hypercapnia,the s100? and IL-6 level was lower than the normal ventilation group.(3)Patients who exhibited cognitive dysfunction had higher s100? levels at day1 and day 2 postoperative compared to those who did not.