The Effect Of Circulatory Arrest Under Mild Hypothermia On Postoperative Renal Function In Patients With Aortic Dissection Aneurysm Of Standford Type A

Objective:It is to compare whether mild hypothermic stopping circulation temperature（30-32℃）has less postoperative renal damage and better protects renal function in patients undergoing aortic dissection aneurysm surgery in Standford type A compared to moderate hypothermic stopping circulation temperature（26-28℃）.Methods:Retrospective analysis of 120 patients with Standford type A aortic dissection who underwent aortic arch replacement at the Department of Cardiovascular Surgery,Second Hospital of Jilin University from December 2017 to January 2021.According to the difference of rectal temperature at the time of intraoperative stopping of circulation,the temperature at the time of stopping of circulation of 30 to 32℃ was set as mild hypothermia group,and the temperature at the time of stopping of circulation of 26 to 28℃ was set as moderate hypothermia group.60 patients were selected from each group.We analyzed the data on the patients’ preoperative general condition,intraoperative operating time,extracorporeal circulation time,cooling time,rewarming time,ascending aortic block time,circulatory arrest time,postoperative creatinine and urea urine volume,changes in creatinine and urea nitrogen during the seven days after surgery,and postoperative hospitalization time,postoperative ICU stay,postoperative awake time,postoperative extubation time,number of consecutive postoperative renal replacement therapy cases,and number of deaths.Results:There was no statistically significant difference in age,gender,BMI,pericardial effusion,previous medical history（hypertension,coronary artery disease,diabetes,COPD,Marfan syndrome,previous cerebrovascular disease,smoking history）,preoperative creatinine,urea nitrogen,and glomerular filtration rate between the two groups of patients.The extracorporeal circulation time,cooling time,and rewarming time were shorter and statistically significant in the mild hypothermia group compared with the moderate hypothermia group.The operative time,ascending aortic block time,and circulatory arrest time were not statistically significant in the two groups.There were statistically significant postoperative urine volume,creatinine value,urea nitrogen,and GFR in both groups.And the postoperative urine volume and GFR in the mild hypothermia group were higher than those in the moderate hypothermia group,and the postoperative creatinine value and urea nitrogen in the mild hypothermia group were lower than those in the moderate hypothermia group.There were no statistically significant differences in the postoperative hospital stay,ICU stay,awake time,extubation time,number of CRRT cases,and number of deaths between the two groups.The creatinine values in the mild hypothermia group were lower than those in the moderate hypothermia group four days after surgery,and the difference was statistically significant.Creatinine values from the fifth to seventh postoperative day were not statistically significant in both groups Urea nitrogen values were lower in the mild hypothermia group than in the moderate hypothermia group two days after surgery,and the difference was statistically significant.No statistically significant values of urea nitrogen existed between the third and seventh postoperative days in both groups Conclusions:Stopping circulation at mild hypothermic anesthesia is beneficial in reducing the duration of extracorporeal circulation and the side effects associated with hypothermia,and postoperative renal function changes fluctuate less in patients who stop circulation at mild hypothermia（30-32℃）compared to moderate hypothermia（26-28℃）.