Risk Factors For Postoperative Hypoxemia In Patients Undergoing Thoracic Surgery

Objective:To identify the risk factors for postoperative hypoxemia in patients undergoing thoracic surgery,and developed a prediction model.Methods:119 patients undergoing selective thoracic surgery under general anesthesia with one lung ventilation form Yijishan Hospital during September 2018 to March2020 were selected.These patients were divided into Hypoxemia group?H?and No Hypoxemia group?N?according to SpO₂?90%on room air after operation in the postanaesthesia care unit?PACU?.The following factors were examined:age,body mass index?BMI?,smoking,heart disease,preoperative hemoglobin?HB?,preoperative albumin?ALB?,American Society of Anesthesiologists?ASA?physical score,ratio of forced expiratory volume in first second to forced vital capacity?FEVI/FVC?,predicted preoperative forced expiratory volume in 1 s?FEV1%?,vital capacity?VC%?,one-lung ventilation time,operation time,anesthesia time,intraoperative propofol,remifentanil,muscle relaxant dose,types of resection,modes of operation,intraoperative fluid volumes and bleeding.Univariate factors analysis verified independent variables were used to the Multivariate logistic regression analysis to find the predictors of postoperative hypoxemia.We developed a prediction model to predict postoperative hypoxemia,and described the receiver-operating characteristic curves?ROC curve?and worked out the area under ROC curve?AUC?.Results:Among 119 patiets,49?41.2%?developed postoperative hypoxemia.Univariate factor analysis showed that the age?P=0.000?,smoking?P=0.018?,ASA physical score?P=0.000?,FEV1/FVC?P=0.011?,FEV1%?P=0.037?,one-lung ventilation time?P=0.001?,operation time?P=0.009?,anesthesia time?P=0.001?,propofol dose?P=0.001?,remifentanil dose?P=0.001?,muscle relaxant dose?P=0.000?,types of resection?P=0.009?,modes of operation?P=0.001?,and intraoperative fluid volumes were significant compared between two groups.Multivariate logistic regression analysis showed that age?P=0.014?,intraoperative fluid volumes?P=0.000?,and ASA physical score?P=0.000?were independent risk factors to predicted the postoperative hypoxemia.The logistic regression equation is Y=-1.358+0.030*Fluid Volumes-1.513*age-2.716*ASA physical score.The model had an area under the ROC curve of 0.836?95%confidence interval 0.763to 0.908?.The sensitivity and specificity of prediction model were 79.6%and 75.7%respectively.Conclusion:The incidence of postoperative hypoxemia in patients undergoing thoracic surgery is high.We deceloped the model using three independent factors?age,fluid volumes,and ASA physical score?to predict postoperative hypoxemia in patients undergoing thoracic surgery.Patients who age?60 years old,ASA physical score more than class II,and more fluid volumes at a higher incidence of postoperative hypoxemia...