The Effects Of Different P_ETCO₂ Levels On Early Postoperative Cognitive Function In Elderly Patients Undergoing Laparoscopic Radical Gastrectomy

Objective:To detective the effects of different end-tidal carbon dioxide level(P_ETCO₂)on early postoperative cognitive function in elderly patients undergoing laparoscopic radical gastrectomy.Methods:Fifty-one ASA?elderly patients of aged 60⁸0y,scheduled for elective radical laparoscopic radical gastrectomy were randomly divided 3 group?n=17?using a random number:group A(P_ETCO₂ 36⁴0 mmHg),group B(P_ETCO₂ 41⁴5 mmHg)and group C(P_ETCO₂ 46⁵0 mmHg).Both side of the cerebral regional oxygen saturation?rSO₂?and hemodynamic parameters were recorded before induction?T₀?,5 min after induction?T₁?,at the beginning of operation?T₂?,1 h?T₃?and 2 h?T₄?after skin incision,at the end of operation?T₅?and 5 min after extubation?T₆?.The blood sample were obtained before surgery?D₀?,1 h?D₁?,1 d?D₂?,and 7 d?D₃?after surgery to detect cytokine interleukin-6?IL-6??S100??neuron-specific enolase?NSE??amyloid protein 42?A?-42?and phosphorylated _D0u protein?p-tau?concentration.The Montreal Cognitive Assessment scale?MoCA?were test before surgery?D₀?,1 d?D₂?,and 7 d?D₃?after surgery.Results:A total 42 cases were included in the statistical analysis.There were 14cases in each group.There was no significant difference in age,years of education,hemoglobin concentration,complications,operation time,urine volume,fluid infusion and blood loss?P>0.05?.The incidence of POCD D₂ was 42.9%,including 7 cases?50.0%?in group A,8cases?57.1%?in group B,and 3 cases?21.4%?in group C.The incidence of POCD was 23.8%at D₃,including 3 cases?21.4%?in group A,4 cases?28.6%?in group B,and 2 cases?14.3%?in group C.The incidence of POCD at D₂ and D₃ in group C was lower than groups A and B.MoCA score in groups A,B and C at D₂ were significantly lower than D₀?P<0.05?.MoCA score at T_c was still lower than D₀,but the difference was not statistically significant?P>0.05?.In groups A,B and C,T₁^T₅ rSO₂ was significantly lower than T₀,and the difference was statistically significant?P<0.05?.The rSO₂ of group C was higher than that of group A and B,but the difference was sD0tistically significant only at2h after surgery?T₄??P<0.05?.Serum IL-6 concentration was significantly higher at D₁ than D₀?P<0.05?,and higher than groups A and B at D₂ and D₃,the difference was statistically significant?P<0.05?.Serum S100?concentration began to increase significantly at D₂,and the difference was statistically significant compared with that in D₀?P<0.05?.Serum S100?concentration in group C was lower than group A?P<0.05?.Serum S100?concentration decreased at D₃,but the difference was still s_D0tistically significant compared with that at D₀?P<0.05?.Serum S100 concentration in group C was still lower than group A?P<0.05?.There was significant difference in serum NSE concentration at D0^D3?P<0.05?in each group.Serum NSE concentration increased at D₁ and D₂ continuously,and the difference was statistically significant compared with D₀?P<0.05?.Serum NSE concentration decreased at D₃,and the difference was statistically significant?P<0.05?.Serum A-42 protein concentration in D₂ increased,and the difference was statistically significant compared with D₀?P<0.05?.Serum A-42 protein concentration in group C was significantly lower than group A?P<0.05?.Serum A-42 protein decreased at D_3,and Serum A-42 protein in group C was significantly lower than that in group A and B at D₃?P<0.05?.Serum p-tau protein concentration in D₂ increased,and the difference was statistically significant compared with D₀?P<0.05?.Serum p-tau protein concentration in group C was significantly lower than group A?P<0.05?.Serum p-tau protein concentration in D₃ decreased,and the difference was still statistically significant compared with D₀?P<0.05?.In addition,serum p-tau protein concentration in group C was significantly lower group A at D₃?p<0.05?.There was no statistically significant difference between P_ETCO₂ and P_aCO₂between groups A,B and C at T₁^T₅?P>0.05?.Correlation analysis of P_ETCO₂ and P_aCO₂ at T₂^T₄ shows a strong positive correlation?r>0.5,P<0.05?.Correlation analysis of P_ETCO₂ and rSO₂ was conducted at T₃^T₅,and there was a positive correlation between them?r>0.3,P<0.05?.Intraoperative low rSO2 events were recorded.There were 5 cases in group A?41.7%?,2 cases in group B?14.7%?and 0 cases in group C?P>0.05?.There was no significant difference in other postoperative complications?P>0.05?.Conclusion:Maintaining higher PETCO2 during operation can stabilize the intraoperative hemodynamic parameters of elderly patients undergoing laparoscopic radical gastrectomy and increase the intraoperative cerebral oxygen saturation.Reduce concentration of IL-6?S100??NSE,deposition of amyloid protein and tau protein phosphorylation.However,there is no sufficient evidence to improve the incidence of postoperative cognitive dysfunction by increasing PETCO2.