A Study Of Predicting Model For Post-Operative Delirium In Orthopedic Surgery Of Elderly Patients

BackgroundPost-operative Delirium is a common complication in Orthopedic patients.Also known as the acute mental confusion,delirium is a kind of acute mental pathological syndrome with cognitive dysfunction and related symptoms.Its special characteristic is the acute fluctuation process accompanied with conscious,cognitive,perceptive chaos.The diagnosis of delirium is not complicated,because it can be easily confirmed by its special clinical feature.The most widely used diagnostic criteria is the Confusion Assessment Method(CAM).The consequence of the delirium,however,is relatively serious.The delirium may lead let the patients lose their self-care ability,slow their recovery of function.More importantly,it could increase the percentage of complications,mortality,nursing difficulty,impatient cost.In the early years,most of the studies about delirium were in the subjects of pathergasiology,anesthesia,intensive medicine,etc.Nowadays,with the constant improvement of the society and the progress of surgical techniques and methods,the post-operative delirium is becoming the research focus.Because it could help the patients get longer and healthier life with high quality.The delirium is a common disease involved with multi-subjects.Although there are many studies about it,the controversies are still exist in the aspects of epidemiology,mechanism,treatment.One of the most widely recognized consensus is that the older age is a high risk factor.Elderly patients take a great part in orthopaedic.Developing a predicting model for post-operative delirium can help medical personnel identify patients at high risk of POD and reduce the incidence of delirium,which is positive for the patients' prognosis.ObjectiveTo develop an effective predicting model for post-operative delirium in orthopedic surgery of elderly patients and evaluate its effectiveness.MethodsThis is a prospective study.A total of 148 patient were enrolled in the development cohort.18 risk factors were recorded including age,sex,height,weight,BMI,education,drinking or smoking history,basic disease(high blood pressure,diabetes,dyslipidemia,cerebrocvascular or psychological diseases),blood biochemistry(pre-operative albumin and hematocrit),electrolyte,waiting time for operation,operative duration,intraoperative blood transfusion.After the surgery,all patients were assessed daily until discharged.The patient were divided into two groups: POD group and non-POD group.Chi-square test and t test screening were use to identify the risk factors.Then the related continuous data of risk factors were layered and the independent risk factors were separated by the multivariate Logistic regression.The preventing model was designed according to the result.The predicting cohort concluded 66 patients which were scored by the model.The model was evaluated by the developing cohort and the predicting cohort.ResultIn the developing cohort,there are 61 males and 87 females(58.8%)and the age is 60-87 years old(average 68.48±6.58 years).Twelve(8.1%)of the patients developed POD,including 6 males(50%)and 6 females(50%).The risk factors of age,education,cerebrocvascular or psychological diseases,albumin,intraoperative allogeneic variant blood transfusion were statistical significant different between the POD and non-POD groups(P<0.05).The statistical significant different were not found in the factors of height,weight,BMI,high blood pressure,diabetes,dyslipidemia,hematocrit,electrolyte disorder,waiting time for operation,operative duration,intraoperative autologous blood transfusion(P>0.05).The multivariate Logistic regression showed that age?75(OR:3.57,P=0.087),educated less than 9 years(OR:2.107,P=0.003),the allogeneic variant blood transfusion(OR:5.65,P=0.042)were independent risk factors for POD.The predicting cohort included 66 patient and 6(9%)of them were developed into delirium.The predicting model were valued by the OR of the independent risk factors.The risk point equals 3 points(age ?75)+ 2 points(education less than 9 years)+ 5 points(intraoperative foreign blood transfusion).The validity of the model were tested by ROC curves: AUC(developing cohort)=0.66 and AUC(predicting cohort)=0.75.ConclusionThe delirium is a common and serious postoperative complication,which endanger the elder patient in orthopedics and cause adverse impact on prognosis for a long period.This research found that age,cerebrovascular or psychological disease,low state of education,low albumin,intraoperative allogeneic variant blood transfusion were associated with the occurrence of delirium.Age?75,education less than 9 years,intraoperative foreign blood transfusion were independent risk factors for post operative delirium.