Hemodynamic Study Of Septic Shock In Premature Infants And Its Evaluation Of Prognosis

Background&Objective:Late onset septic shock is the main cause of death in very low birth weight infants(VLBW),which can lead to multiple organ failure and a series of long-term complications.The guidelines for the diagnosis and treatment of septic shock in adults,children and full-term newborns recommend target hemodynamic management.The treatment targets include cardiac output index CI>3.3 L/(m2·min).However,there are few studies on the hemodynamics of VLB W septic shock,and there is no consensus on its target CI.The value of ultrasonic cardiac output monitor USCOM in hemodynamic evaluation of critically ill newborns has been affirmed.The aim of this study is to establish the hemodynamic physiological reference of VLB W,to identify how different degrees of maturity influence cardiovascular alterations during the postnatal period,to analyze the hemodynamic characteristics of different stages of septic shock,to explore the risk factors of shock progression into adverse prognosis,to evaluate the predictive value of CI for adverse prognosis,and explore its target intervention value.Methods:1.Very low birth weight,low birth weight and term infants hospitalized in NICU of our hospital were selected.Hemodynamics of 24h,48h,72h,7d and 3 0d after birth were continuously monitored by USCOM,including cardiac index CI,peripheral vascular resistance index SVRI and Smith-Madigan inotropy index SMII.The changes of hemodynamics of preterm infants with different gestational age and weight were compared.2.VLBW with late-onset sepsis in our hospital were studied,the hemodynamic differences between the early stage of septic shock and the shock stage were analyzed,and look for indicators to identify the progress of shock.Analyze the risk factors of shock progression to persistent shock and death;Evaluate the predictive value of CI on the adverse prognosis of septic shock and find out the target intervention value.Results:A total of 270 children were studied.150 cases were included in the study of hemodynamics and physiology,including 50 cases in VLBW group,50 cases in LBW group and 50 cases in term infants.The CI,SVI,SVRI and DO2 of VLB W at five time points after birth were significantly lower than those of LBW group and full-term group(P<0.001).With the increase of age,the above indexes increased gradually,and the difference was statistically significant(P<0.001).120 cases of VLBW septic shock,40 cases in the early shock group,40 cases in the shock group and 40 cases in the healthy control group were included.SVRI 790 ±160d/s/cm5/m2 in the early shock group was significantly lower than 1300 ±155d/s/cm5/m2 in the control group,CI 4.2±0.61/min/m2 and DO285±15ml/m2/min were significantly higher than 3.0±0.21/min/m2 and 75±13ml/m2/min in the control group.Characteristics of shock group:56%were low SVRI and high CI mode,25%were low CI and high SVRI mode,and 10%were low CI and low SVRI mode.As the disease progresses,the low SVRI mode may change to the low CI mode.In the shock group,47.5%of the children had early reversal of shock,52.5%had persistent shock,of which 12.5%died.Compared with the survival subgroup,CI and SMII decreased significantly by 25%and 20%(P=0.008,P=0.000),and DO2 decreased significantly by 25%.The infants with shock were divided into early reversal group and persistent shock group.The risk factors of progression to persistent shock and death were analyzed.The results showed that CI and Lactic acid were risk factors.The value of 0.5h-CI and 0h and 3h LAC levels in judging adverse prognosis was compared.The area under the curve of 0.5h-CI was the largest 0.98,the sensitivity was 90.5%,the specificity was 94.7%,and the corresponding CI value was 2.81/min/m2.It had a good prediction effect on shock related death and organ dysfunction.Conclusion:1.The hemodynamic physiological basis of VLBW is fast heart rate,reduced myocardial contractility,peripheral vascular resistance and oxygen delivery.With the increase of gestational age and day,it showed a trend of dynamic development and maturity.2.The decrease of SVRI can help early identify septic shock in VLBW.The decrease of CI is the characteristic of shock entering the decompensated stage,significant decrease of CI increases is the risk factor of death.3.0.5h-CI is a good index to predict death and multiple organ dysfunction in septic shock of VLBW.CI>2.81/(m2·min)may be the target value of septic shock treatment in VLBW.