| Objective: Brain injury related to cardiopulmonary bypass (CPB) is one of the main complications after cardiac surgery. The severe brain injury could develop to death. The infants with low age, low weight and complicated malformation, because of their central nervous system in form and function are not immature yet, are more susceptible to brain injury than adults with congenital heart diseases. It has been proved that the neuroproteins S100βsub-type (S100βprotein) and neuron-specific enolase (NSE) released into the circulation are most special biochemical markers for brain injury. The study was designed to test and analysed the perioperative serum levels of S100βand NSE in infants with cyanosis and non-cyanosis congenital heart disease. The effect and possible mechanism of brain injury by CPB were explored to find the suitable CPB for the cyanosis and non-cyanosis congenital heart disease. The research will lay foundation for clinical prevention and cure.Methods: Thirty infants with congenital heart diseases were randomly selected and divided into cyanosis group and non-cyanosis group. For the cyanosis group (n=18), 10 male and 8 female infants with tetralogy of Fallot were managed, the average age: (3.2±1.9) years, the average weight: (12.1±7.4) Kg, preoperative Hb (161±14) g/L and Hct (52.5±3.7)%. For the non-cyanosis group (n=12), 7 male and 5 female infants with ventricualr septal defect, the average age: (3.5±2.0) years, the average weight: 12.6±7.9 Kg, preoperative Hb: (136±9) g/L and Hct: (38.2±3.1)%. There were no renal failure, cerebral diseases before operation for all patients. There was no statistical difference in age, sex and weight between two groups. All patients were treated with the same anesthetized method, the same CPB equipments and management methods. At preoperative time(T1), immediately the end of CPB(T2), 5 hours(T3), 12 hours(T4), 24 hours(T5) and 48 hours(T6) after CPB, serial artery blood samples were taken; the blood serum levels of S100βand neuron-specific enolase (NSE) were analyzed by Enzyme-Linked Immunosorbent Assay (ELISA) method. The time of cardiopulmonary bypass, aortic cross-clamping, postoperative mechanical ventilation, ICU (Intensive Care Unit) staying and the hospitalization days were annaled. All data was analyzed with statistics method.Result:1. General results after operationAll patients were successfully accomplished. No human factors were occurred with brain injury. For the cyanosis group, the CPB time was (79.2±32.1) min, and the aortic cross-clamping time was (43.1±21.0) min. For the non-cyanosis group, the CPB time was (58.0±21.1) min, and the aortic cross-clamping time was (24.2±11.4) min. Compared with these two groups, there were significant difference (t=3A24, P<0.01; t=5.034, P<0.001) . All patients in two groups had no hypoxemia, renal failure, stable haemodynamics, had no muscular spasms or hemiparalysis symptoms and urinary productions were more than 1 mL/(kg.h). They were all successful in stopping breathing machine and discharged.2. Changes in serum concentrations of S100βprotein and NSEThe serum concentrations of S100βprotein and NSE rose gradually and reached the high-peak at 5 hours after CPB in two groups. Then they decreased slowly, and most of that would be returned to normal levels within 48h after CPB.3. Comparison of serum concentrations of S100βprotein and NSE between the two groupsAt first, the homogeneity test for variance of two groups in different time was conducted (P>0.05). The test indicated that the sampling variances of them are equal. The mean comparison t-test between two groups in different time after CPB was made then. The results showed that the serum concentrations of S100βprotein and NSE were higher obviously in the cyanosis group than those of non-cyanosis group at end of CPB, 5h, 12h and 24h after CPB (P<0.05), but the serum concentrations of S100βprotein and NSE in the two groups had no significant difference (P>0.05) before the operation. In order to determine the effect of CPB leading to the serum concentrations of S100βprotein and NSE, the correlation analysis between the CPB time and the serum concentrations, between aortic cross-clamping time and the serum concentration were made. The results showed that the serum concentrations of S100βprotein and NSE at different time points after CPB operation are positively related with CPB time and aorta clamping time (P<0.05). The correlativity of S100βprotein and NSE with serum concentrations is highest at 5 hours after CPB (P<0.05).Conclusion:1. The brain injures after cardiac surgery with CPB are mainly caused by CPB itself in infants. Most of the injuries are in sub-clinical damage condition, and some of them are reversible. Dynamically observing the levels of S100βand NSE are of great clinical value for forecasting the developing tendency of cerebral injury and evaluating therapeutic efficacy in infant patients after cardiac surgery with CPB.2. The occurrence rate of brain injury in cyanosis infants is higher than that in non-cyanosis infants at the earlier period after operation. The perioperative cerebral protection of cyanosis infants should be paid more attention to.3. The brain injury after CPB operation was closely related with CPB time and aortic cross-clamping time. In order to reduce brain injury, the CPB and aortic cross-clamping time should be shorten as soon as possible. |
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