A Correlation Study On The Intraoperative Common Carotid Arterial Blood Flow And Perioperative Delirium In Elderly Patients

Objective: To explore the correlation between the change of blood flow in the common carotid artery and emergence delirium and postoperative delirium during general anesthesia.It provides a new method for identifying risk factors and preventing perioperative delirium.Methods: This study was a prospective nested case control study.A total of 98 elderly patients who underwent abdominal surgery in our hospital from April 2021 to December 2021 were included in the study.Preoperative visits were conducted on the day before surgery to assess cognition,sleep,anxiety,and preoperative comorbidities.After entering the operating room,vector flow technology(V Flow)was used to measure the baseline carotid common artery blood flow,arterial plaque,vascular elasticity and other indicators,as well as vital signs such as blood pressure,heart rate and oxygen saturation after entering the room.All patients received general anesthesia induction and maintenance with conventional anesthesia.Blood flow of the common carotid artery and corresponding vital signs parameters were measured every 10 minutes after anesthesia until the end of surgery.After surgery,the patient was admitted to the Postanesthesia care unit(PACU),and postoperative blood samples were collected.Richmond agitation sedation scale and Confusion Assessment Method for the Intensive Care Unit(CAM-ICU)were used to evaluate whether the patient had emergence delirium(ED).35 patients with emergence delirium(ED group)and 63 patients with non-emergence delirium(non-ED group)were evaluated.After patients returned to the ward,3-Minute Diagnostic Assessment-Confusion Assessment Method(3D-CAM)was used to assess whether Postoperative delirium(POD)occurred during postoperative hospitalization.14 patients with postoperative delirium(POD group)and84 patients with non-postoperative delirium(non-POD group)were evaluated.Group comparison between ED group and non-ED group,POD group and non-POD group in preoperative cognition,sleep,anxiety and depression score,comorbidities,baseline vital signs,baseline carotid blood flow,arterial plaque,vascular elasticity,and the duration of intraoperative decrease of blood flow of the common carotid artery above baseline by 10%,20%,30%,40%,50%,and increase by 10%,20%,intraoperative anesthetic drug dosage,transfusion volume,blood loss and other influencing factors,the difference of the amount of variables with significant differences were included in binary Logistic regression analysis to explore their independent effects,and their diagnostic value for delirium was analyzed using the receiver operator characteristic curve(ROC).The stay time in PACU,postoperative tube length,postoperative pain for three days,sleep status,and hospital stay were further analyzed to explore the correlation between delirium and adverse prognostic indicators.At the same time,the blood flow velocity table collected during the operation was derived,and the value of analyzing the characteristics of blood flow velocity image for the prediction of delirium was preliminarily discussed by machine learning.In addition,preoperative and postoperative plasma samples were obtained,Simoa was used to measure the levels of Neurofilament(Nf L)and Glial Fibrillary Acidic Protein(GFAP)in preoperative and postoperative plasma samples.Finally,the correlation between intraoperative carotid blood flow and other monitoring indicators was analyzed,and a multiple linear regression model was established to evaluate the influence of intraoperative heart rate,mean arterial pressure,end-tidal carbon dioxide and other indicators on intraoperative carotid blood flow.Result: The study found that The duration of a 30% decrease in carotid blood flow over baseline was positively associated with the occurrence of ED(OR:1.091 95%CI:1.008-1.182,P=0.031).While,there was no significant difference in blood flow changes between the POD group and the non-POD group.In addition,blood transfusion status was an independent risk factor for ED(OR: 5.658 95%CI: 1.023-31.303,P=0.047).The characteristics of blood flow velocity were also of great value in the prediction of ED(AUC: 0.908,ACC: 0.860).The increase of Nf L in ED group was more significant than that in non-ED group(P=0.023).The increase of GFAP in POD group was more significant than that in non-POD group(P=0.033).Delirium was also associated with longer PACU retention and more significant postoperative pain.In addition,carotid arterial blood flow decreased significantly(28.33%)after induction of general anesthesia,and heart rate,end-tidal carbon dioxide,and peak flow velocity of the common carotid artery were independent influencing factors.Conclusion: In elderly patients undergoing abdominal surgery,intraoperative decrease in carotid blood flow over 30% at baseline was positively associated with ED.Perioperative delirium may accompany the occurrence of nerve damage.Monitoring the decrease of the central rate,end-tidal carbon dioxide and the peak flow velocity of the common carotid artery can provides more reference for timely detection of the decrease of the blood flow of the common carotid artery.