| Objective The effect of cardiopulmonary bypass pump flow/blood pressue on cerebral perfusion was seldom reported in pediatric patients who underwent congenital heart disease repairment surgery assited with cardiopulmonary bypass(CPB).Cerebral autoregulation was seldom reported in pediatric patients with congenital heart disease underwent cardiopulmonary bypass(CPB).The aim of this study was to detect whether blood flow or blood pressure during cardiopulmonary bypass has effect on the cerebral perfusion and the regional cerebral oxygen saturation(rSO2).Besides,this reseaech was intend to investigate whether the regional cerebral oxygen is consistent with the degree of brain injury by detecting the expression level of the related protein in the plasma biomarkers and hippocampal neurons.Methods Twenty Chinese experimental miniature juvenile piglets were divided into five groups randomly(n = 4).Piglets in the control group(C)received thoracotomy only.The experimental groups contained high CPB pump flow with high blood pressure group(H1),high CPB pump flow with low blood pressure group(H2),low CPB pump flow with high blood pressure group(L1)and low CPB pump flow with low blood flow group(L2).A unique double arterial line with single pump was utilized in this experiment.High CPB pump flow was set in the range of 100 to 120 ml/kg.min and low CPB pump flow was 50 to 70 ml/kg · min;high blood pressure was was set in the range of 50 to 70 mmHg and low blood pressure was 30 to 50mmHg.The CPB pump flow and the blood pressure were only controlled accroding to the predefined range during the aortic cross-clamping.Near infrared reflectance spectroscopy(NIRS)was used to monitor the real-time rSO2,and the perfision flow was measured by using TS410 transit-time tubing flowmeters.Plasma samples were drawn at four time points,incluede with T0,15 minutes after intubation and before initiation of CPB;T1,5 minutes after the beginning of CPB;T2,right after the begining of the rewarming;T3,10 minutes after the release of the aortic clamping.The rSO2,blood flow,MAP,etc.were recored every five mintues.The serum S-100B,neuron-specific enolase(NSE),matrix metalloproteinase-2,matrix metalloproteinase-9,neutrophil gelatinase-associated lipocalin levels were tested at these four time points.And all the values were calculated at these four time points described above.The blood gas analysis was conducted at three time points,T0,T1 and T3,respectively.Results There were no significant differences in baseline parameters among the two experimental groups and the control group.The cerebral perfusion flow was significant lower in the high CPB pump flow(H)groups than that in the low CPB pump flow(L)groups[(67±2)ml/(kg · min)vs.(105 ±5)ml/(kg · min),P<0.001]during the aortic cross-clamping,but there was no significant difference between the high blood pressure groups and the low blood pressure groups in cerebral perfusion flow.And there was a significant positive correlation between cerebral perfusion flow and CPB pump flow during the aortic cross-clamping in the H group and the L gorup(H group:R2=0.277,P<0.001,L group:R2=0.323,P<0.001),but the cerebral perfusion flow did not correlate to the MAP.At T1 and T3,there were no significant difference in the rSO2 between the H1 group and the H2 group and between the L1 group and the L2 group.At T2,there was no significant difference in rSO2 between the H1 group and the H2 group(54%±3%Vs.53%±3%,P=0.405),however,the rSO2 of the L2 Group was significantly lower than that of the L1 Group(47%±3%vs 57%±6%,P=0.017).And there is significant positive correlation between the rSO2 and the MAP at T2 in L Group(R2=0.230,95%Confidence Interval:0.111?0.295,P<0.001),while there is no significant positive correlation between the rSO2 and the MAP at T2 in the H Group(R2 = 0.020,95%Confidence Interval:0.020?0.103,P = 0.243).At the T1,T2 and T3 time points(during CPB),the plasma S-100B level(before CPB)increased significantly compared with the level at TO point in the H groups,and the plasma S 100 B level(before CPB)increased significantly only at T2(during the aorta cross-clamping)compared with the level at TO in the L groups,but there was no significant difference among groups at the same time point group and within group at different time point.The plasma NSE level at T1(the beginning of the aorta cross-clamping)was significantly higher than that at TO in the H1 Group,and it was significantly higher at T2 than that at TO in the H2 Group.However,there was no significant difference was in the L group.In addition,MMP-2,MMP-9 and NGAL levels in all groups showed no statistical difference.Meanwhile,there was no significant difference in the expression levels of neurons in HIF-1,AIF and Caspase-3 in the hippocampus CA region,and the results of HE staining and NISSL staining in each group did not show the neuronal necrosis and apoptosis in the hippocampus CA.In the low pump flow group,there was a significant negative correlation between plasma NGAL level and cerebral oxygen saturation(R2=-0.465,95%confidence interval:-4.927?-0.9948,P=0.004),which was not found in the high pump flow group.Conclusion A unique double arterial lines with single pump cardiopulmonary bypass juvenil pig model was constructed successfully in this research.During the aortic cross-clamping with mild hypothermia,the cerebral perfusion flow is only related to the CPB perfusion flow,that is,the cerebral perfusion increased with the increase of CPB perfusion flow,and vice versa;the mean arterial blood pressure had no significant effect on the cerebral perfusion flow.When low flow perfusion is performed,it may be caused by the damage of the integrity of the cerebral autoregulation,which leads to the decrease of the rSO2,and the proper improvement of blood pressure could improve the rSO2.Despite the low pump flow with low blood pressure induced a transient regional cerebral oxygen saturation deduced,that may not cause obvious central nervous system injury. |
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