Effects Of The Degree Of Trendelenburg Angles On Brain Function In Patients Undergoing Laparoscopic Surgery

Background and ObjectiveLaparoscopic surgery has been widely used in clinical practice in recent years.In order to obtain a good surgical field of vision,pneumoperitoneum and Trendelenburg position(T position)are often required during the surgery.Studies have shown that prolonged pneumoperitoneum and T position may lead to cerebral blood volume increase,intracranial pressure(ICP)rise and brain automatic regulation impairment.During robot-assisted laparoscopic radical prostatectomy surgery,patients’ICP increased by 12.5%.Because an elevated ICP may lead to cerebral hypoperfusion and decreased cerebral blood flow,resulting in cerebral ischemia.Postoperative cerebral insufficiency and hypoxia are considered to be important factors leading to postoperative cognitive disfunction(POCD)after cardiac surgery.At present,there is no unified standard for the appropriate tilt angle of T position.Previous studies have explored the influence of different T positions on patients’respiratory and circulatory systems and found that with the increase of T position angle,the greater influence on patients’ respiratory and circulatory systems will be.However,there are few studies on the effect of T position from different angles on ICP of patients.When the T-position angle of patients undergoing laparoscopic surgery is increased,it is still unclear how ICP changes under the joint influence of multiple factors such as gravity and brain self-regulation mechanism,whether it will cause cerebral perfusion insufficiency,and what effect it has on postoperative cognitive function of patients.Therefore,this study intends to measure optic nerve sheaths diameter(ONSD)by ultrasound to reflect patients’ ICP to explore whether different T positions would have influence on ICP of patients undergoing laparoscopic surgery.The regional cerebral oxygen saturation(rSO2)was measured during the operation to observe whether different angle of T positions would affect the cerebral perfusion and induce rSO2 changes.And observe the effect of different angle of T positions on postoperative cognitive function of patients.So as to to provide reference for the selection of appropriate angle of T position in laparoscopic surgery.Material and MethodsSelective laparoscopic radical resection of rectal cancer,prostate cancer and hysterectomy,18-65y,BMI 18～25 kg/m2,ASA Ⅰ or Ⅱ,were randomly divided into 3 groups:Trendelenburg position 25°(25Group),Trendelenburg position 30°(30°Group),Trendelenburg position 35°(35°Group).All patients were routine anesthesia induction and mechanical ventilation.After induction of anesthesia(T0),30 min(T1),60 min(T2),90 min(T3)after inflation and Trendelenburg position 5 min(T4)after the surgery,mean arterial pressure(MAP),heart rate(HR),airway peak pressure(Ppk),airway plateau pressure(Pplat),end-expiratory carbon dioxide(PECO2),arterial blood carbon dioxide(PaCO2),and regional cerebral oxygen saturation(rSO2)were recorded.ONSD of patients were measured by ultrasound.mini-mental state examination(MMSE)was used to evaluate the cognitive function of the patients within 7d after operation and to record the adverse events such as postoperative nausea,vomiting,eye pain and headache.SPSS 21.0 statistical software was used to analyze the data.The normal distribution measurement data are expressed as mean±standard deviation(χ±s)and the non-normal distribution quantitative data are described by median and quartile.One way ANOVA and LSD test were used to compare the general data of patients and ANOVA analysis of repeated measurement data was used to compare the data within and between groups during operation.The counting data were compared by chi-square test or Fish exact probability method.P<0.05 was statistically significant.Result1.General data of patients.There was no significant difference in preoperative general data,operating time,anesthesia time,total fluid intake and urine volume(P>0.05).2.Intraoperative MAP and HR of patients.Intra-group comparison:Compared with T0,MAP of patients in the three groups was significantly increased at T1-3(P<0.05).Comparison among groups:MAP and HR of three groups at different time points showed no statistical significance(P>0.05).3.Intraoperative airway pressure of the patients.Intra-group comparison:Compared with T0,Ppk and Pplat of the three groups were significantly increased at T1-3(P<0.05).Comparison between groups:At T0-1 and T4,Ppk and Pplat of 35°group were significantly higher than those of 25° group(P<0.05).At T2-3,Ppk and Pplat of 350 group were significantly higher than those of 25° and 30° group(P<0.05).4.Intraoperative PCO2 and PaCO2 in patients.Intra-group comparison:compared with T0,PETCO2 and PaCO2 in the three groups were significantly increased at T1-4(P<0.05).Comparison among groups:At T0-1,there was no statistical significance in PETCO2 and PaCO2 among the three groups(P>0.05).At T2,PaCO2 in 35° group was significantly higher than that in 25° and 30° groups(P<0.05).At T3,PETCO2 and PaCO2 in 35° group were significantly higher than those in 25° and 30°groups(P<0.05).At T4,PaCO2 in 35° group was significantly higher than that in 25°group(P<0.05).5.ONSD and rSO2 in patients.Intra-group comparison:At T1-3,ONSD and rSO2 in the three groups were significantly increased(P<0.05).Comparison between groups:at T0-1 and T4,there was no significant difference in ONSD among three groups(P>0.05).At T2,ONSD in 35° group was significantly higher than that in 25° group(P<0.05).At T3,ONSD in 35° group was significantly higher than that in 25° group and 30° group(P<0.05).There was no statistical significance in rSO2 among 3 groups at different time points(P>0.05).6.Comparison of MMSE scores of patients.Intra-group comparison:At T1d postoperation-3d postoperation,MMSE scores of patients in the three groups were significantly decreased(P<0.05).Comparison between groups:There was no significant difference in MMSE scores among 3 groups at different time points(P>0.05).Conclusion1.In laparoscopic surgery,different angle of T positions will have an impact on patients’ ICP.When the tilt angle is more than 30°,patients’ ICP is significantly increased.2.During laparoscopic surgery,no change of rSO2 was found at different angle of T positions within 35° and there was no significant difference in the occurrence of postoperative POCD in patients.