Independent Risk Factors Related To Acute Respiratory Distress Syndrome After Acute Type A Aortic Dissection Surgery:A Retrospective Analysis

Objective: Acute type A aortic dissection is a common disease in cardiac surgery,which often needs emergency surgery.However,due to the large range of vascular lesions,multiple organ injury during operation,and the huge difficulty of operation,patients are prone to various complications after operation.Acute respiratory distress syndrome(ARDS)is a serious complication,which not only increases the postoperative mechanical ventilation time and hospital stay,but also has a serious adverse impact on the prognosis.Therefore,early identification of risk factors related to ARDS and taking measures play an important role in reducing the incidence of ARDS after surgery and improving the prognosis of patients.Methods: the clinical data of 147 patients with acute type A aortic dissection who underwent extracardiac surgery in our hospital from January 2015 to December 2019 were retrospectively analyzed.The age,gender,height,weight,body mass index(BMI),smoking history,hypertension history and diabetes history of all patients were recorded at the time of admission in hospital.The left ventricular ejection fraction(LVEF),white blood cell(WBC),hemoglobin(HB),platelet(PLT)and deep hypothermia and circulatory arrest(DHCA)were recorded;DHCA time,ACC time,CPB time,operation time;postoperative bleeding,secondary thoracotomy hemostasis,re intubation,shock(systolic blood pressure,SBP < 90 mm Hg),cardiac care unit(cardiac care unit,CCU),duration of mechanical ventilation,dialysis,cerebral infarction,length of hospital stay,and perioperative transfusion of red blood cells and plasma.Oxygenation index(OI = Pa O2 / Fi O2)was collected 1-7 days after operation,and the worst value of oxygenation index was taken as statistical record.All patients were divided into ARDS group and non ARDS(NARDS)group according to the occurrence of ARDS.First,the univariate logistic regression analysis was performed,and then all the variables with P < 0.1 and the variables possibly related to ARDS were included in the multivariate logistic regression analysis.The final regression model was established by stepwise regression method to screen out the independent risk factors related to ARDS.The variance inflation factor(VIF)was used to diagnose the multicollinearity of all the variables included in the multivariate regression analysis model.If the Vif was greater than 10,the corresponding variables were removed.Receiver operating characteristic curve(ROC)was used to evaluate the prediction efficiency of the final model,and the area under the curve was used to quantitatively describe the prediction efficiency.The difference was statistically significant when p value was less than 0.05.Results: A total of 147 patients with acute type A aortic dissection were included,including 110 males with an average age of(51.9 ± 10.1)years and 37 females with an average age of(54.3 ± 11.1)years.25 patients(17.0%)developed ARDS after operation,including 5 mild cases(3.4%),13 moderate cases(8.8%)and 7 severe cases(4.8%).Oxygenation index changes of two groups of patients 7 days after operation: oxygenation index of nards group increased significantly on the second day after operation,and that of ARDS group increased significantly on the third day after operation;oxygenation index of two groups of patients was close on the sixth and seventh day after operation.The results of univariate analysis showed that age(P =0.073),smoking(P = 0.089),WBC(P = 0.034),ACC time(P = 0.006),CPB time(P =0.005),DHCA time(P = 0.001),perioperative red blood cell transfusion(P = 0.031) and plasma volume(P = 0.002)might have predictive value for ARDS,P < 0.1.The multivariate logistic regression model showed that CPB time(OR = 1.012,95% CI:1.001-1.022,P = 0.027),DHCA cycle time(OR = 1.067,95% CI: 1.014-1.124,P =0.013),perioperative blood transfusion volume(OR = 1.001,95% CI: 1.000-1.002,P= 0.011)were independently correlated with ARDS.The Vif of all variables included in the equation is less than 10,and there is no multicollinearity.ROC curve analysis demonstrated a good discrimination ability of the logistic regression model,with an area under the curve of 0.835,95%CI 0.740-0.929,P=0.000.Conclusion:(1)DHCA time,CPB time and perioperative plasma transfusion were independent risk factors for ARDS after operation of acute type A aortic dissection.(2)The oxygenation index of nards group increased significantly on the second day,and that of ARDS group increased significantly on the third day;the oxygenation index of the two groups was similar on the sixth and seventh day.(3)This is a single center retrospective study.It is hoped that multi center study can provide more information,so as to more accurately estimate the risk factors of ARDS after operation of acute type A aortic dissection.