Study Of Left Ventricular Function In Preterm Infants With Respiratory Distress Syndrome By Ultrasound Speckle Tracking Imaging Technology

Neonatal respiratory distress syndrome(NRDS)is prevalent in preterm infants.Incidence is related to gestational age,the smaller the gestational age,the higher the incidence,the lower the body weight,the higher the mortality.Severe premature infants often have respiratory and heart failure.In preterm infants with respiratory distress syndrome,cardiac function is affected by various factors such as hypoxia and inflammatory response.It is generally believed that laboratory examination of abnormal cardiac enzymes(such as CK-MB and other indicators)may indicate cardiac injury.However,the sensitivity and specificity of the indicators are different,and multiple invasive examinations will cause some damage to infants.Cardiac function is one of the important indexes for the evaluation of premature infants’ clinical status and long-term prognosis.Therefore,the evaluation of premature cardiac function has the key clinical value and significance.Conventional echocardiography parameters can be used to evaluate left ventricular function through ejection fraction,which has limited sensitivity and is not easy to find early myocardial damage.However,speckle tracking imaging technology can more accurately evaluate myocardial deformation,which has been gradually recognized in clinical practice.This study used two-dimensional speckle tracking imaging(2DSTI)and other ultrasound techniques to predict the value of cardiac function in preterm infants with respiratory distress syndrome,and to study the consistency of different doctors on the evaluation of speckle tracking analysis,and analyze the clinical application value of 2DSTI technology in newborn left ventricular function.Correlation analysis was conducted between strain parameters and clinical indicators to provide reference data for the cardiac function evaluation of NRDS preterm infants with different clinical characteristics.Meanwhile,the results were compared with those of preterm infants without NRDS and normal term infants to evaluate the myocardial damage of NRDS preterm infants,so as to provide reference for clinical intervention and prognosis of NRDS preterm infants.Part1 Study on the repeatability of left ventricular myocardial strain in neonates by ultrasound speckle tracking imaging technologyObjectiveTo study the repeatability of sonographer using 2DSTI technology to evaluate left ventricular myocardial longitudinal strain in newborns such as preterm infants with NRDS,so as to provide an effective clinical reference value for 2DSTI technology to evaluate cardiac function in such populations.MethodsThis study enrolled 20 preterm infants with NRDS and 11 normal term infants controls.And the basic clinical data were collected and compared.Doctors A and B performed 2DSTI analysis on the neonatal cardiac dynamic images and recorded the corresponding heart rate and longitudinal strain parameters: LV-GLPS-A3 C 、LV-GLPS-A4C、LV-GLPS-A2C、LV-GLPS-Avg.Two weeks later,the same doctor A again performed strain analysis of the image with the speckle tracking technology.The consistency of strain parameters between intraobserver and interobserver was compared.ResultsBland-Altman consistency analysis showed that the strain parameters measured by the two-dimensional speckle tracking analyses in intraobserver and interobserver had good consistency.The consistency of ICC(>0.80)measured between interobserver and intraobserver was good.The absolute value of CV ranged from 6.26 to 13.2% in intraobserver and interobserver.Conclusion2DSTI technology repeated measurements of left ventricular myocardial longitudinal strain have good consistency in neonates.2DSTI technology can be further applied as an effective method for ventricular function analysis in neonates.Part2 Study on the correlation between the left ventricular myocardial strain detected by ultrasound STI technology and the clinical index of cardiac function in neonatesObjectiveTo study the correlation of the longitudinal strain of neonatal left ventricular myocardium measured by 2DSTI technology with the changes clinical index of cardiac function,and the clinical value of 2DSTI strain parameters in evaluating cardiac function change was discussed.MethodsThis study enrolled 20 preterm infants with NRDS and 11 normal term infants controls.We compared the clinical data of these groups.Clinical data include: gestational age,weight,partial pressure of carbon dioxide,CK-MB,partial pressure of oxygen,blood sugar,oxygen saturation of blood,birth length,birth head circumference,etc.The ultrasonic parameters of cardiac function included PASP,CO and MAPSE.See the part one for strain data.2DSTI strain data of two groups were collected.Pearson correlation analysis was used to evaluate the correlation between strain parameters and the clinical index.ResultsComparison between the group of NRDS preterm infants and the normal term infants group: There were differences in three concave signs,gestational age,birth weight,CO,partial pressure of oxygen,blood sugar,oxygen saturation of blood,birth length,birth head circumference(P<0.05 for all),while no statistical differences were found in CK-MB,PCO2,hemoglobin,Apgar score results(P>0.05).Correlation analysis of the absolute value of the mean global longitudinal strain of the left ventricle with clinical data: strain was positively correlated with gestational age(r=0.671,P<0.05),body weight(r=0.608,P<0.05);the strain had no correlation with CK-MB(r=0.127,P>0.05),PCO2(r=0.376,P>0.05).Correlation analysis between the absolute value of the mean global longitudinal strain of the left ventricle and conventional ultrasonic measurements: the strain was positively correlated with CO(r=0.664,P<0.05)and MAPSE(r=0.689,P<0.05),but no correlation with PASP(r=0.018,P>0.05).ConclusionStrain parameters can reflect the myocardial contractility of infants with different body weight,gestational age and CO,and MAPSE just like the longitudinal deformation of myocardium,except that MAPSE has no regional strain analysis.Part3 Study on the evaluation of left ventricular function in preterm infants with respiratory distress syndrome by ultrasound STI technologyObjectiveTo study the evaluation value of 2DSTI technology in evaluating the cardiac function of NRDS preterm infants,so as to provide reference significance for improving the cardiopulmonary care of NRDS preterm infants.MethodsThis study enrolled 20 preterm infants with NRDS,10 preterm infants without NRDS and 11 term infants controls.1.Collection of ultrasound parameters including: MAPSE,TAPSE,HR;IVS,LVPW,LVEDS,LVEDD,LAD,PDA;LVEF-M,LVFS-M,SV,LVEDV(Simpson),LVESV(Simpson),CO;AV,MV-E,MV-A,PV,TV-E,TV-A,PASP;MV-s’,MV-E ’,MV-A’,E/E ’,LV-Tei,TV-S’,TV-E ’,TV-A’,RV-Tei.The difference of traditional ultrasonic parameters between the preterm infants with NRDS and term infants were compared.2.And LVEF,MV-E,MV-A,MV-S’,MAPSE and LV-Tei parameters of the preterm infants without NRDS were collected.The differences of three groups of above parameters were analyzed and compared.3.Strain data were collected: The left ventricular longitudinal strain parameters were measured by 2DSTI technique among the three groups,and the results of the three groups were compared.Results1.Left ventricular function was compared between NRDS preterm infant group and term infant control group.(1)HR in preterm infants with NRDS was higher than term control group(P<0.05);MAPSE and TAPSE in preterm infants with NRDS were lower than term control group,with statistically significant differences(P<0.05).(2)IVS,LVPW,LVEDS,LVEDD and LAD in preterm infants with NRDS were all lower than term control group,PDA size was higher than term control group,with statistically significant differences between the two groups(P<0.05).(3)SV,LVEDV(Simpson),LVESV(Simpson)and CO in preterm infants with NRDS were all lower than term control group,and the difference between the two groups was statistically significant(P<0.05).(4)AV in preterm infants with NRDS group was lower than term control group(P<0.05).PV,TV-E,and TV-A in preterm infants with NRDS were all lower than term control group(P<0.05),while PASP in preterm infants with NRDS was higher than term control group(P<0.05).(5)Compared with term control group,the measurements of MV-S’,MV-E’,TV-S’,TV-E’ were decreased in preterm infants with NRDS(P<0.05),while LV-Tei was higher in preterm infants with NRDS(P<0.05).(6)While there was no statistically significant difference between the two group in LVEF-M,LVFS-M and LVEF(Simpson)(P>0.05).And there was no statistically significant difference between the two groups in MV-E,MV-A(P>0.05).Also there was no statistically significant difference in MV-A’,E/e ’,TV-A’ and RV-Tei between the two groups(P>0.05).2.Left ventricular function was compared among preterm infants NRDS,preterm infants without NRDS and term control group.Compared with the other two groups,MV-S’ and MAPSE of preterm infants with NRDS decreased,and LV-Tei increased(P<0.05).There was no significant difference in LVEF,MV-E and MV-A between the three groups(P>0.05).3.Comparison of measured strain parameters among the three groups of preterm infants NRDS,preterm infants without NRDS and term control group.(1)The differences of left ventricular longitudinal strain LV-GLPS-A3 C,LV-GLPS-A2 C,LV-GLPS-Avg,anterior wall,anterior ventricular septum,posterior ventricular septum,inferior wall,lateral wall,basal Avg,intermediate Avg and apical Avg in this three groups were statistically significant(P<0.05).There was no statistically significant difference in LV-GLPS-A4 C and posterior wall in this three groups(P<0.05).(2)Compared with preterm infants without NRDS and term control group,the LV-GLPS-A3 C,LV-GLPS-A2 C,LV-GLPS-Avg,anterior wall,anterior ventricular septum,posterior ventricular septum,lateral wall,intermediate Avg,and apical Avg in preterm infants with NRDS all decreased,and the differences were statistically significant(P<0.05).(3)There was no statistically significant difference between preterm infants without NRDS and term control group LV-GLPS-A4 C,LV-GLPS-A3 C,LV-GLPS-A2 C,LV-GLPS-Avg,anterior wall,anterior ventricular septum,posterior ventricular septum,posterior wall,lateral wall,basal Avg,intermediate Avg,apical Avg(P>0.05).Inferior wall in preterm infants without NRDS was lower than term control,and the difference was statistically significant(P<0.05).ConclusionThe 2DSTI technology can be more sensitive than ejection fraction to evaluate the left ventricular function of preterm infants with NRDS,and provide clinical reference value for the analysis of the changes of left ventricular systolic function in the whole and local areas.