Effect of small for gestational age on hemodynamic parameters in the neonatal period

Baroreflex Sensitivity and Blood Pressure in Premature Infants – Dependence on Gestational Age, Postnatal Age and Sex

To characterize the differences in baroreflex sensitivity (BRS), blood pressure (BP), heart rate (HR) and respiration rate (RR) in preterm infants with a similar postconceptional age reached by various combinations of gestational and postnatal ages. To detect potential sex differences in assessed cardiovascular parameters. The study included 49 children (24 boys and 25 girls), postconceptional age 34.6±1.9 weeks. Two subgroups of infants were selected with the similar postconceptional age (PcA) and current weight, but differing in gestational (GA) and postnatal (PnA) ages, as well as two matched subgroups of boys and girls. Blood pressure (BP) was recorded continuously using Portapres device (FMS). A stationary segment of 250 beat-to-beat BP values was analyzed for each child. Baroreflex sensitivity (BRS) was calculated by cross-correlation sequence method. Despite the same PcA age and current weight, children with longer GA had higher BRS, diastolic and mean BP than children with shorter GA and longer PnA age. Postconceptional age in preterm infants is a parameter of maturation better predicting baroreflex sensitivity and blood pressure values compared to postnatal age. Sex related differences in BRS, BP, HR and RR were not found in our group of preterm infants.

Blood Pressure Variability and Baroreflex Sensitivity in Premature Newborns-An Effect of Postconceptional and Gestational Age

Introduction: Cardiovascular system is the vitally important system in the dynamical adaptation process of the newborns to the extrauterine environment. To reliably detect immaturity in the given organ system, it is crucial to study the development of the organ functions in relation to maturation process. Objectives: The objective was to determine the changes in the spontaneous short-term blood pressure variability (BPV) and baroreflex sensitivity (BRS) reflecting various aspects of cardiovascular control during the process of maturation in preterm babies and to separate effects of gestational age and postnatal age. Methods: Thirty-three prematurely born infants without any signs of cardio-respiratory disorders (gestational age: 31.8, range: 27-36 weeks; birth weight: 1,704, range: 820-2,730 grams) were enrolled. Continuous peripheral blood pressure signal was obtained by non-invasive volume-clamp photoplethysmography method during supine rest. The recordings of 250 continuous beat-to-beat blood pressure values were processed by spectral analysis of BPV (assessed measures: total power, low frequency and high frequency powers of systolic BPV) and BRS calculation. For each infant we also assessed systolic, diastolic and mean blood pressures, heart rate and respiratory rate. Results: With the postconceptional age, BPV measures decreased (for total power: Spearman correlation coefficient r_s = -0.345, P = 0.049; for low frequency power: r_s = -0.365, P = 0.037; for high frequency power r_s = -0.349; P = 0.046); and BRS increased significantly (r_s = 0.448, P = 0.009). The further analysis demonstrated that these effects were more attributable to gestational age than to postnatal age. BRS correlated negatively with BPV magnitude (r_s = -0.479 to -0.592, P = 0.001-0.005). Mean blood pressure and diastolic blood pressure increased during maturation (r_s = 0.517 and 0.537, P = 0.002 and 0.001, respectively) while heart rate and respiratory rate decreased (r_s = -0.366 and -0.516, P = 0.036 and 0.002, respectively). Conclusion: We conclude that maturation process is accompanied by an increased involvement of baroreflex buffering of spontaneous short-term blood pressure oscillations. Gestational age plays a dominant role not only in BPV changes but also in BRS, mean blood pressure, diastolic blood pressure and heart rate changes.

Neonatal Blood Pressure Standards: What Is "Normal"?

Blood pressure (BP) is routinely measured in newborn infants. Published BP nomograms demonstrate a rise in BP following delivery in healthy infants at all gestational ages (GA) and evidence that BP values are higher with increasing birth weight and GA. However, the complex physiology that occurs in newborn infants and range of BP values observed at all GA make it difficult to identify "normal" BP for a specific infant at a specific time under specific conditions. As such, complete hemodynamic assessment should include the physical examination, perinatal history, other vital signs, and laboratory values in addition to BP values.

A prospective observational study comparing cardiac function of small for gestational age with appropriate for gestational age babies using serial echocardiographic studies

BACKGROUND

Approximately 30% of babies born in India are low birth weight (LBW) and about 70% of LBW babies are small for gestational age (SGA). Though there are several trials that have evaluated cardiac function of intrauterine growth restricted (IUGR) babies in utero, there is limited data about postnatal cardiac function in SGA babies during early neonatal period. This study was conducted to evaluate the cardiac functions of SGA babies by serial echocardiographic measurements and compare this with appropriate for gestational age (AGA) babies during the early postnatal period.

MATERIAL AND METHODS

Seventy babies were enrolled in this prospective observational study with 35 each in the SGA and AGA groups. Echocardiography was performed for all babies on days 1, 2, and 3 of life. Myocardial performance index (MPI) was used as the primary measure to compare cardiac function. MPI was calculated for both ventricles using pulse wave Doppler and tissue Doppler.

RESULTS

MPI of the left ventricle was significantly higher in the SGA group as compared to AGA babies during all the three measurement periods with SGA babies having significantly higher MPI of right ventricle on day 1 and day 2 but not on day 3. Left ventricular internal diameter index during diastole and systole (LVIDD index and LVIDS index), left atrium: aortic root ratio (LA:AO ratio) were significantly increased in SGA babies on all the occasions. Fractional shortening, ejection fraction, and area shortening were similar in two groups.

CONCLUSIONS

Myocardial performance index of left and right ventricle, which evaluates both systolic and diastolic function of ventricles, was significantly increased in SGA babies in comparison to AGA babies during the first 3 days of life except MPI of the right ventricle on day 3. Thus, SGA babies have compromised cardiac function through all phases of the cardiac cycle with the performance improving spontaneously over time.

Uncomplicated Pregnancies and Ultrasounds for Fetal Growth Restriction: A Pilot Randomized Clinical Trial

Objective The purpose of this multicenter pilot study was to determine the feasibility of randomizing uncomplicated pregnancies (UPs) to have third trimester ultrasonographic exams (USE) versus routine prenatal care (RPNC) to improve the detection of small for gestational age (SGA; birth weight < 10% for GA). Material and Methods At three referral centers, 50 UPs were randomized after gestational diabetes was ruled out. Women needed to screen, consenting, and loss to follow-up was ascertained, as was the detection rate of SGA in the two groups. Results During the study period at the three centers, there were 7,680 births, of which 64% were uncomplicated. Of the 234 women approached for randomization, 36% declined. We recruited 149 women and had follow-up delivery data on 97%. The antenatal detection rate of SGA in the intervention group was 67% (95% confidence intervals 31-91%) and 9% (0.5-43%) in control. Conclusion The pilot study provides feasibility data for a multicenter randomized clinical trial to determine if third trimester USE, compared with RPNC, improves the detection of SGA and composite neonatal morbidity.

Preeclampsia: effect on newborn blood pressure in the 3 days following preterm birth: a cohort study

Maternal hypertension and preeclampsia are associated with greater risk of hypertension in childhood, and cardiovascular events in adulthood. However, whether preeclampsia affects blood pressure (BP) in the newborn period is unclear. Previous neonatal studies were based on small sample sizes, very low birth weight or gestational age or limited duration (h). To delineate hemodynamic repercussions of maternal preeclampsia on preterm infants (gestational ages ⩾29 weeks) with/without intrauterine growth restriction (IUGR) in the first 3 postnatal days, we conducted a single-centre retrospective cohort study of singleton births at 29-35 weeks of gestation in Montreal, Canada, from 2008 to 2011. Data were obtained from medical charts. Exclusion criteria included congenital anomalies, infections, pre-pregnancy maternal hypertension and gestational diabetes. IUGR was defined as birth weight <10th percentile. Of the 338 eligible neonates, 230 were included: 75 preeclampsia-IUGR, 72 preeclampsia-only and 83 controls. The preeclampsia-IUGR group had longer gestations than the preeclampsia-only or control groups (32.4±1.8 vs. 31.3±1.6 vs. 31.7±1.6 weeks, respectively; P<0.001). Mean BPs increased over the first 3 days for all newborns (P<0.001). Infants with preeclampsia-associated IUGR had the highest systolic and diastolic BPs, even after adjustment for birth weight, and preeclampsia-only the next highest. Systolic BP progression showed significant differences between groups (P<0.05). We conclude that impact of preeclampsia on children blood pressure was manifest within days of birth, over and above coexisting IUGR. Long-term cardiovascular follow-up and targeted preventive strategies are advised for this underrecognized high-risk population.