Effects Of Controlled Hypotension Duration On Postoperative Cognitive Function And Possible Mechanisms

Objective:To observe the effect of controlled hypotensive with different duration on Tau-181 and Aβ-42 protein and inflammatory factors in patients undergoing endoscopic surgery for pituitary adenomas,and to explore the safe range of different durations of controlled hypotension.Methods:60 patients whom were taken elective nasal endoscopic pituitary adenoma,aged32-65 years,ASA I-II,were divided into three groups:control group（C group）,control hypotension group 2h group（Group A1）,control hypotension group 3h group（A2 group）,and N=20.The control group C was not treated,group A1 and A2 were treated with sodium nitroprusside（SNP）and esmolol at a constant speed.The blood pressure was reduced to the target blood pressure within 10 min,the blood pressure was adjusted by adjusting the pump speed.The mean arterial pressure（MAP）was maintained within a safe range of 55-65 mmHg.The patient’s central venous blood was collected.Serum Aβ-42 and p-Tau-181 protein levels and inflammatory cytokines IL-6 and TNF-αwere measured by ELISA at the time 10 minutes before the anesthesia（T₀）、the end of the surgery（T₁）、1 day after the operation（T₂）、3 days after operation（T₃）and 7 days after operation（T₄）.The Mini-Mental State Examination Scale（MMSE）was used to assess the patient’s cognitive function status atT₀,T₂,T₃,and T₄ time point.Results::1.The expression of serum Aβ-42 protein and p-Tau-181 protein in the three groups after surgery was increased compared with preoperative（P<0.05）.Compared with group C,the expression of Aβ-42 protein and p-Tau-181protein was increased in group A2 at T₂ and T₃（P<0.05）.Compared with group A1,the expression of Aβ-42protein and p-Tau-181 protein was increased in group A2 at T₂ and T₃（P<0.05）.2.There were no cognitive dysfunction in the three groups before operation.The MMSE at the time points of T₂,T₃,and T₄ in all three groups were lower than those in T₀（P<0.05）.Compared with group C,the MMSE scores were lower in group A2 at T₂ and T₃（P<0.05）;Compared with group A1,the MMSE scores of group A2 at T₂and T₃ decreased（P<0.05）.Compared with group C,the incidence of POCD in group A1 was not statistically significant（P>0.05）,the incidence of POCD was increased in group A2 at T₂ and T₃（P<0.05）.Compared with group A1,the incidence of POCD in group A2 at T₂ and T₃ was increased;at the T₄ time point,the incidence of POCD in the three groups was not statistically significant（P>0.05）.3.The serum levels of IL-6 and TNF-αincreased after surgery in all three groups（P<0.05）.Compared with group C,the levels of serum IL-6 and TNF-αincreased in group A2 at T₂ and T₃（P<0.05）;Compared with group A1,the levels of serum IL-6and TNF-αwere increased in group A2 at T₂ and T₃（P<0.05）.Conclusion:1.Controlled hypotensive for 3 hours can cause increase of Aβ-42 protein and p-Tau-181 protein expression;2.Short-term（within 2 hours）controlled hypotension does not increase the incidence of short-term cognitive dysfunction,while long-term（more than 3 hours）controlled hypotension will increase short-term cognitive dysfunction;3.Controlled hypotension can increase the level of inflammatory factors and increase the incidence of postoperative cognitive function.