Clinical Study Of Bacterial DNA Translation After Cardiopulmonary Bypass For Congenital Heart Disease

Objective: Blood bacterial DNA in children with congenital heart disease(CHD)undergoing cardiopulmonary bypass surgery was detected by the polymerase chain reaction(PCR)method,and compared with serum diamine oxidase(DAO),intestinal fatty acid binding protein(IFABP)and postoperative systemic inflammatory response syndrome(SIRS),to explore the relationship among postoperative intestinal barrier damage,intestinal bacterial translocation and postoperative SIRS.Methods: A total of 61 children undergoing CPB for surgical correction of CHD were recruited in our study.The cases with manifestations of intestinal infection before surgery were excluded such as diarrhea,positive result of fecal leukocytes and so on.The patients were divided into several matched groups based on different classifications.According to preoperative CHD type,the patients were divided into complex CHD group and simple CHD group.SIRS group and non-SIRS group were grouped according to the occurrence of SIRS after CPB.According to the polymerase chain reaction(PCR)results,the patients were divided into PCR-positive group and PCR-negative group.The copy number of blood bacterial DNA were determined by PCR in blood sample before CPB,after CPB 2h and 24 h.At the same time,the level of serum diamine oxidase(DAO)and intestinal fatty acid binding protein(IFABP)were detected by enzyme linked immunosorbent assay(ELISA).The occurrence of SIRS after CPB was observed.Statistical analyses were performed with t-test and Spearman’s rho statistic between matched groups.Results:1.The positive rate of PCR was 83.6%(51 / 61)at 2 hours and 24 hours after operation,which was significantly higher than that before operation(P < 0.0001).The copy number of bacterial DNA was significantly higher at 2 hours and 24 hours after operation than that before operation(P < 0.0001).There was no significant difference in the number of bacterial DNA copies after operation between simple CHD group and complex CHD group(P > 0.05).2.The levels of DAO and IFABP in serum increased immediately at 2 hours after CPB,and began to decrease at 24 hours after CPB.There was a significant difference(P value is less than 0.01)at pre-operation,2 hours and 24 hours after CPB.3.The level of DAO in serum was positively correlated with the operation time(P =0.0254,r = 0.29).And serum DAO level was positively correlated with the copy number of bacterial q PCR(P =0.0295,r = 0.28).The level of DAO in the SIRS group increased significantly at24 hours postoperatively,which was significantly different from that in the non-SIRS group(P = 0.0308).Serum DAO level in the PCR-positive group was significantly increased at 24 hours after operation,and was significantly different from those in the PCR-negative group(P = 0.0168).There was no significant difference in serum DAO levels at different time point between the simple CHD group and the complex CHD group(P >0.05);4.Serum IFABP level was markedly positively correlated with the operation time(P = 0.0248,r = 0.27).The level of IFABP in the SIRS group increased significantly at 24 hours after surgery,which was significantly different from that in the SIRS group(P = 0.0282).Serum IFABP level increased in the PCR positive group at 2 hours and 24 hours after surgery,but there was no significant difference compared with the PCR negative group(P> 0.05).The serum IFABP level in the simple CHD group and the complex CHD group at 2 hours after surgery was markedly higher than that in the simple CHD group,and the difference was significant(P = 0.0093),but there was no significant difference of the serum IFABP level at 24 hours postoperative between groups(P> 0.05).There was a significant positive correlation between serum IFABP levels and peripheral blood leukocytes 24 hours after surgery(P = 0.0011,r =0.4).Conclusions:1.Intestinal bacterial DNA translocation can occur in the early period after CPB;2.Intestinal barrier injury,occur at the early stage after cardiopulmonary bypass,is closely related to bacterial DNA translocation and the time of CPB;3.Intestinal damage index DAO in serum is positively related to intestinal bacterial DNA copy number,and the DAO level in SIRS group is significantly higher than that in non-SIRS group,suggesting that SIRS is closely involved in bacterial DNA translocation;4.Serum IFABP level was positively correlated with the increase of leukocyte in peripheral blood,suggesting that the intestinal barrier injury after cardiopulmonary bypass may aggravate the inflammatory response.