Research Of Early Postnatal Hemodynamic Changes With Preterm

For preterm infants the transition from fetal circulation to the normal cycle in the early stages of birth is complex. Due to the early delivery, a sudden increase in vascular resistance,myocardium immature,poorly developed peripheral vascular smooth muscle, adrenal insufficiency,associated with serious infections, arterial catheters have led the premature suffered in the postnatal days. Because of the unstable of transition period, the preterm are prone to hypotension, shock, and other cardiovascular dysfunction, leading to systemic hypoperfusion, cerebral hemorrhage, periventricular leukomalacia. Therefore, hemodynamic monitoring in preterm during postnatal days is benefit for the prevention of complications and improve the prognosis of preterm infants.This subject intends to apply ultrasonic cardiac output monitor(USCOM) and Echocardiography(ECHO), combining with blood pressure to observe the dynamics of early postnatal hemodynamic within 72 hours after birth. With ECHO monitoring arterial catheter size, analysis of different gestational age groups naturally ductus arteriosus closure time and the impact on the circulation. The last part is preliminary analysis of mechanical ventilation’s impact on noninvasive hemodynamic monitoring.Part Ⅰ Research of hemodynamic changes with different gestational age preterm infants within 72 hoursObjectiveTo explore the hemodynamic changes of different gestational age preterm infants within 72 hours after born and compare the trend of cardiac function of different time points with the same gestational age group.Methods1 Objective From October 2013 to May 2014, a total of 209 cases of preterm admitted in departments of NICU in Guangdong General Hospital, after the exclusion 74 patients were included in this study.2 Groups According to gestational age divided into three groups, GA<32w,32w≤GA <34w,34w≤GA<37w. Each group were checked at 4h,24h,48h,72h after birth, using USCOM to record the dynamics trends of related indicators.3 Indicators Cardiac index (CI), Smith Madigan SMIItropy Index (SMII), Systemic vascular resistance index (SVRI) and other indicators using USCOM at four time points. using the US company GE’s DINAMAP Procare 100 sphygmomanometer with baby arm cuff blood pressure measurements to calculate the mean blood pressure (MBP).Results1 Basic Information There were 74 cases of premature met the inclusion criteria including GA<32w 27 cases,32w≤GA<34w 25cases,34w≤GA<37w 22 cases, including 35 cases accepted pulmonary surfactant treatment, all preterm were treated to PS intubation mechanical ventilation, ventilation average time was 7h; noninvasive assisted ventilation was used when breathing situation improved, ventilation average time was 29.5 h.2 Comparison of different gestational age within 72 hours after birth in preterm 2.1 three gestational age groups was no significant difference in 4h CI after birth, but with the increase in gestational age of the rise; in the remaining three time points, GA<32w CI group were higher than the other two groups (P<0.05); and 32w≤GA<34w between 34w≤GA<37w with CI was no significant difference (P> 0.05). 2.2 with increasing gestational age, SMII at four time points are on the rise, which 34w≤GA<37w of SMII significantly higher than the other two groups (P <0.05); and GA<32w and 32w≤GA<SMII varies between 34w is not obvious. 2.3, three gestational age groups was no significant difference in 4h SVRI after birth, but with the increase in gestational age of the rise; in the remaining three time points, GA<32w SVRI group were lower than the other two groups (P <0.05);there was no significant difference between 34w≤GA<37w (P> 0.05).3 Trends with the same gestational age at different time points of CI SMII SVRI and MBPWith gestational age group at different time points in CI was declining, in which the smaller gestational age, postnatal CI fluctuations more obvious. SVRI in gestational age <32w group have a significant decrease in 24h; while the other two groups SVRI showed an increasing trend, and gradually stabilized. SMII and MBP presented the same trend, while the smaller the gestational age increased, the more obvious.ConclusionThe hemodynamic changes was fluctuat, especially in the group of GA<32w. Along with gestational age increased, cardiac performance and cardiac function gradually stabilized, so get the normal hemodynamic reference values can be further known the function and apply to the clinical to reduce the unnecessary drug use, reduce complications in preterm infants.Part Ⅱ Research of ductus arteriosus and dynamic changes with cardiac index, peripheral vascular resistance, blood pressure about different gestational age neonatesObjectiveTo investigate the ductus arteriosus closure time of different gestational age neonates and compare the trends of cardiac index(CI), peripheral vascular resistance index (SVRI) and blood pressure. Know more about the hemodynamic changes after duct arterial closed.Methods1 objective From October 2013 to May 2014 95 cases of neonates were admitted in departments of NICU in Guangdong General Hospital, including 20 cases of full-term babies,74 cases of premature infants2 Inclusion criteria Vital signs are stable; appropriate for gestational age babyies;3 Exclusion criteria: congenital malformations, severe asphyxia, meconium aspiration syndrome, severe infection, persistent pulmonary hypertension; postnatal require use of vasoactive drugs.4 GroupsAccording to gestational ag divided into four groups, GA<32w,32w≤GA<34w, 34w≤GA<37w, GA≥37w; ECHO monitor the closure of the ductus arteriosus, USCOM obtain CI, SVRI at 5 time points,24h,48h,72h,7d,14d respectively.Results1 Basic InformationAfter screening there are 74 cases included in the study, including 27cases of GA <32w,25cases of 32w≤GA<34w,34w≤GA<37w 22cases, GA≥37w 20cases2 Different gestational age newborns ductus arteriosus natural closing timeIn the group of 34w<GA<37w and GA>37w,ductus arteriosus closure rate was 61% and 90% respectively;and in early preterm infants of 32w≤GA<34w spontaneous closure of ductus arteriosus is 44% at 24h after birth.But when GA<32w the rate of ductus arteriosus closure was 59.1% at 72h, of which 9 cases needed ibuprofen and 1 patent was conducted ductus arteriosus ligation.The difference of cumulative closure rate with 4 groups based on gestational age at five time points was statistically significant (P<0.05).3 The trends of SVRI, blood pressure and CI after ductus arteriosus closuredThere were significant differences of systolic blood pressure, diastolic blood pressure and SVRI(P<0.001).And these indicators were increased,whereas CI decreased in preterm infants(P<0.001) after the ductus arteriosus closed.But in term children CI had no significant changes with PDA(P>0.05). With increasing gestational age, systolic blood pressure and SVRI showed an upward trend, diastolic blood pressure with no obvious trend and CI no significant change.ConclusionTerm and late preterm children have a high rate of spontaneous closure of ductus arteriosus at 24 hours after birth, but when gestational age<32 weeks, there still have nearly 33 percent require medical or surgical intervention. Ductus arteriosus has an influence on cardiac function and peripheral resistance in preterm. But cardiac function in term infants has no significant change.So for preterm children, especially very low birth weight preterm, using ECHO and other hemodynamic monitors can early detect patent ductus arteriosus (PDA), reduce complications and improve the survival rate of preterm infants.Part Ⅲ Assess the accuracy of the critically ill early preterm in cardiac output with two methodsObjectiveAssess the accuracy and factors of ultrasonic cardiac output monitor (USCOM) in cardiac output (CO) of critically ill early pretermMethods1 objective From October 2013 to May 2014 35 cases of early preterm in departments ofNICU in Guangdong General Hospital Inclusion criteriaPreterm with RDS after birth who require mechanical ventilation and pulmonary surfactant (PS) replacement therapy;vital signs are stable; gestational age <34 weeks, appropriate for gestational age. Track the index unil the babies without any respiratory support, circulatory stability, feeding tolerance, waiting for discharge.2 Exclusion criteria:congenital malformations, severe asphyxia, meconium aspiration syndrome, severe infection, persistent pulmonary hypertension; postnatal require use of vasoactive drugs; In addition to PDA, PFO has no other cardiac malformations. Pregnant mother generally in good condition, no infection, no cardiopulmonary disease.3 Data collection: Record every preterm heart rate(HR), aortic outflow tract diameter (OTD), pulmonary OTD, aortic VTI, pulmonary valve VTI, LVO, RVO using USCOM and ECHO With ECHO measured PDA, PFO size, shunt direction; recording ventilator parameters (mode, peak inspiratory pressure PIP, PEEP, frequency, inspired oxygen concentration FiO2); Apgar scores, birth ways, prenatal completion lung maturity, birth weight, length and so on.Results1 When ventilated left ventricular output (LVO) measured by USCOM and ECHO were (361±62) ml/min and (376±93) ml/min, respectively; while the right ventricular output(RVO) were (608±152) ml/min and (453±106) ml/min,respectively.Comparison by 2 techniques for LVO showed a bias±limits of agreement of (-0.2±205.7) ml/min, the average percentage error was 54.7%;for RVO,the bias±limits of agreements of (174.3±312) ml/min, the average percentage error of 112%.2 But when without any respiratory support LVO were (394±95)ml/min和(374±55); while RVO were (585±103)ml/min 和(453±106)ml/min,respectively.Comparison by 2 techniques for LVO showed a bias±limits of agreement of (-20.2±119.5) ml/min, the average percentage error was 26.5%;for RVO,the bias±limits of agreements of (104±219.8) ml/min, the average percentage error of 67.2%.ConclusionThe consistency of USCOM and ECHO in LVO and RVO is poor when used in preterm infants during mechanical ventilation;which may be related to endogenous end-expiratory pressure (PEEP), average airway pressure (MAP), transition and other factors, so cardiac function assessment in critically ill preterm during mechanical ventilation needs further study.But USCOM used in these infants without any respiratory support is reliable.