Effect And Mechanisms Of Repeated Intranasal Administration Of Insulin On Postoperative Delirium In Elderly Patients Undergoing Abdominal Surgery

Objective:To observe the effect and possible mechanisms of repeated intranasal administration of insulin on postoperative delirium in elderly patients undergoing abdominal surgery.Methods:From August 2019 to December 2019,ninety elderly patients scheduled for laparoscopic radical gastrointestinal tumor resection under general anesthesia were randomly divided into two groups,45 cases for each group.There were 51 males and 49females.The inclusion criteria included body mass index(BMI)?28 kg/m 2 and American society of anesthesiologists(ASA)status of ???.Control group(group C):0.5 mL saline was administered nasally,bid,2 days before surgery;Insulin group(group I):20 U(0.5 mL)insulin was administered nasally,bid,2 days before surgery,until 10 min before anesthesia on the day of surgery.Record general patient information before surgery,including age,gender,body mass index,education,operation time,ASA classification,and type of radical operation.Blood samples of the internal jugular vein were taken and the serum Tumor necrosis factor alpha(TNF-?),Interleukin-6(IL-6)and Interleukin-1?(IL-1?)concentrations were measured by enzyme-linked immunosorbent assay(ELISA)before giving insulin or saline for the first time(t0),at the end of surgery(t1),1 day after surgery(t2),3 days after surgery(t3),and 5 days after surgery(t4).At t2,t3,and t4,numeric rating scales(NRS)were used to record the pain level of patients,and the confusion assessment method for the intensive care unit(CAM-ICU)was used to evaluate the occurrence of postoperative delirium.At the same time,the episodes of hypoglycemia after nasal administration of insulin or saline for 2 days before surgery was recorded.The blood glucose levels before nasal administration(S0)and at the end of surgery(t1)on the day of surgery were recorded.In addition,the patient's heart rate(HR),systolic blood pressure(SBP),diastolic blood pressure(DBP),mean arterial pressure(MAP)and pulse oximetry(SPO2)were recorded when entering the operating room(T0),induction of anesthesia(T1),intubation(T2),incision(T3),end of surgery(T4),extubation(T5)and discharge from the operating room(T6).Results:There was no significant difference in age,gender,BMI,education,operation time,ASA classification,and type of radical surgery between the two groups(P>0.05).Compared with the control group,the incidence of delirium in the insulin group during t2 and t3 significantly decreased(P<0.05).The serum levels of inflammatory factors including TNF-?,IL-6 and IL-1? in group I were significantly lower than those in control group at t1,t2 and t3(P<0.05).In both groups,the serum levels of inflammatory factors—TNF-?,IL-6 and IL-1?—in t1,t2,t3 and t4 was significantly higher than t0(P<0.05).There was no significant difference in pain scores between the two groups of patients at t2,t3,and t4(P>0.05)No hypoglycemia occurred in both groups after nasal administration of insulin or saline for 2 days before surgery.There was no decrease in blood glucose levels in both groups at SO and t1(P>0.05).There were no significant differences in HR,SBP,DBP,MAP and SPO2 between the two groups at T0,T1,T2,T3,T4,T5 and T6(P>0.05).Conclusion:Repeated intranasal administration of insulin could prevent the occurrence of delirium on the first and third days after abdominal surgery in elderly patients,and reduce the serum concentrations of TNF-?,IL-6 and IL-1? without increasing hypoglycemia.