The Impact Of The Intraoperative Regional Cerebral Spectroscopy Fluctuation On Perioperative Neurocognitive Outcomes In Abdominal Surgeries Among The Elderly

Objectives:This study explores the relationship between changes in regional cerebral oxygen saturation（r Sc O₂）and postoperative delirium（POD）in elderly patients undergoing abdominal surgery,and analyzes the risk factors of POD to provide advice for clinical practice.Methods:This study was a single-center,prospective,observational cohort study.197 patients who underwent elective abdominal surgery were recruited.Demographic and medical data were recorded.Montreal Cognitive Assessment（MOCA）and Mini Mental State Examination（MMSE）were performed on the 1 3 preoperative days and 5～7 days after surgery to assess whether patients had delayed neurocognitive recovery（DNR）.Delirium was assessed using the Confusion Assessment Method（CAM）on the first 3 postoperative days.The r Sc O₂of bilateral hemispheres was recorded at T₀（air inhalation）and T₁（oxygen inhalation with Sp O₂≥98%）.The average bilateral r Sc O₂value from T₀to T₁was used as baseline r Sc O₂value,and the blood gas analysis at T₁（before skin incision）,T₃（1h after incision）,T₄（2h after incision）and T₅（at end of surgery）were recorded.According to whether patients occurred POD,they were divided into two groups:POD group（Group P）and non-POD group（Group N）,and the intraoperative r Sc O₂changes of two groups were compared,the risk factors of POD and the association between POD and DNR were analyzed.Results:197 patients were analyzed in our study,64 patients in Group P and 133patients in Group N.The incidence of POD was 32.49%.Probable cognitive impairment defined by MOCA,the incidence of DNR was 31.98%.The preoperative r Sc O₂in Group P was lower than that in Group N,and there were no significant difference between two groups（59.6±0.99 vs 61.2±0.48,P=0.114）;10%lower than preoperative r Sc O₂was defined as the threshold,and the duration of time below 10%threshold in Group P was longer than that in Group N,and there were no significant difference between two groups（16.5±8.0 vs 8.7±2.5,P=0.777）.The area under the curve below10%threshold in Group P was higher than that in Group N and there were no significant difference between two groups（35.3±12.8 vs 28.3±11.2,P=0.633）.The frequency of dexmedetomidine use was higher in Group N[28（43.75%）vs 81（60.90%）,P=0.0233].The frequency of dexamethasone use was higher in Group N[13（20.31%）vs52（39.10%）,P=0.0086].The frequency of ephedrine use was higher in Group N[42（65.63%）vs 106（79.70%）,P=0.0323].The frequency of norepinephrine use was higher in Group N[15（23.44%）vs 50（37.59%）,P=0.0478].Multivariable analysis showed that the incidence of DNR was associated with POD（OR=3.69,95%CI1.84～7.04）;and other two factors include low education level（OR=0.882,95%CI0.796～0.977）and age（OR=1.089,95%CI 1.013～1.170）were significantly related to POD.Conclusion:This study shows that r Sc O₂monitoring in elderly patients undergoing abdominal surgery cannot predict the development of POD.The use of dexmedetomidine,dexamethasone,ephedrine and norepinephrine may reduce the incidence of POD.The incidence of POD was correlated with DNR,and advanced age and lower education level were risk factors for POD and DNR.