Cost estimation alongside a multi-regional, multi-country randomized trial of antenatal ultrasound in five low-and-middle-income countries

BACKGROUND

Improving maternal health has been a primary goal of international health agencies for many years, with the aim of reducing maternal and child deaths and improving access to antenatal care (ANC) services, particularly in low-and-middle-income countries (LMICs). Health interventions with these aims have received more attention from a clinical effectiveness perspective than for cost impact and economic efficiency.

METHODS

We collected data on resource use and costs as part of a large, multi-country study assessing the use of routine antenatal screening ultrasound (US) with the aim of considering the implications for economic efficiency. We assessed typical antenatal outpatient and hospital-based (facility) care for pregnant women, in general, with selective complication-related data collection in women participating in a large maternal health registry and clinical trial in five LMICs. We estimated average costs from a facility/health system perspective for outpatient and inpatient services. We converted all country-level currency cost estimates to 2015 United States dollars (USD). We compared average costs across countries for ANC visits, deliveries, higher-risk pregnancies, and complications, and conducted sensitivity analyses.

RESULTS

Our study included sites in five countries representing different regions. Overall, the relative cost of individual ANC and delivery-related healthcare use was consistent among countries, generally corresponding to country-specific income levels. ANC outpatient visit cost estimates per patient among countries ranged from 15 to 30 USD, based on average counts for visits with and without US. Estimates for antenatal screening US visits were more costly than non-US visits. Costs associated with higher-risk pregnancies were influenced by rates of hospital delivery by cesarean section (mean per person delivery cost estimate range: 25-65 USD).

CONCLUSIONS

Despite substantial differences among countries in infrastructures and health system capacity, there were similarities in resource allocation, delivery location, and country-level challenges. Overall, there was no clear suggestion that adding antenatal screening US would result in either major cost savings or major cost increases. However, antenatal screening US would have higher training and maintenance costs. Given the lack of clinical effectiveness evidence and greater resource constraints of LMICs, it is unlikely that introducing antenatal screening US would be economically efficient in these settings--on the demand side (i.e., patients) or supply side (i.e., healthcare providers).

TRIAL REGISTRATION

Trial number: NCT01990625 (First posted: November 21, 2013 on https://clinicaltrials.gov ).

Association of haemoglobin levels in the first trimester and at 26-30 weeks with fetal and neonatal outcomes: a secondary analysis of the Global Network for Women's and Children's Health's ASPIRIN Trial

OBJECTIVE

Limited data are available from low- and middle-income countries (LMICs) on the relationship of haemoglobin levels to adverse outcomes at different times during pregnancy. We evaluated the association of haemoglobin levels in nulliparous women at two times in pregnancy with pregnancy outcomes.

DESIGN

ASPIRIN Trial data were used to study the association between haemoglobin levels measured at 6⁺⁰ -13⁺⁶  weeks and 26⁺⁰ -30⁺⁰  weeks of gestation with fetal and neonatal outcomes.

SETTING

Obstetric care facilities in Pakistan, India, Kenya, Zambia, The Democratic Republic of the Congo and Guatemala.

POPULATION

A total of 11 976 pregnant women.

METHODS

Generalised linear models were used to obtain adjusted relative risks and 95% CI for adverse outcomes.

MAIN OUTCOME MEASURES

Preterm birth, stillbirth, neonatal death, small for gestational age (SGA) and birthweight <2500 g.

RESULTS

The mean haemoglobin levels at 6⁺⁰ -13⁺⁶  weeks and at 26-30 weeks of gestation were 116 g/l (SD 17) and 107 g/l (SD 15), respectively. In general, pregnancy outcomes were better with increasing haemoglobin. At 6⁺⁰ -13⁺⁶  weeks of gestation, stillbirth, SGA and birthweight <2500 g, were significantly associated with haemoglobin of 70-89 g/l compared with haemoglobin of 110-129 g/l The relationships of adverse pregnancy outcomes with various haemoglobin levels were more marked at 26-30 weeks of gestation.

CONCLUSIONS

Both lower and some higher haemoglobin concentrations are associated with adverse fetal and neonatal outcomes at 6⁺⁰ -13⁺⁶  weeks and at 26-30 weeks of gestation, although the relationship with low haemoglobin levels appears more consistent and generally stronger.

TWEETABLE ABSTRACT

Both lower and some higher haemoglobin concentrations were associated with adverse fetal and neonatal outcomes at 6-13 weeks and 26-30 weeks of gestation.

Routine antenatal ultrasound in low- and middle-income countries: first look - a cluster randomised trial

OBJECTIVE

Ultrasound is widely regarded as an important adjunct to antenatal care (ANC) to guide practice and reduce perinatal mortality. We assessed the impact of ANC ultrasound use at health centres in resource-limited countries.

DESIGN

Cluster randomised trial.

SETTING

Clusters within five countries (Democratic Republic of Congo, Guatemala, Kenya, Pakistan, and Zambia) METHODS: Clusters were randomised to standard ANC or standard care plus two ultrasounds and referral for complications. The study trained providers in intervention clusters to perform basic obstetric ultrasounds.

MAIN OUTCOME MEASURES

The primary outcome was a composite of maternal mortality, maternal near-miss mortality, stillbirth, and neonatal mortality.

RESULTS

During the 24-month trial, 28 intervention and 28 control clusters had 24 263 and 23 160 births, respectively; 78% in the intervention clusters received at least one study ultrasound; 60% received two. The prevalence of conditions noted including twins, placenta previa, and abnormal lie was within expected ranges. 9% were referred for an ultrasound-diagnosed condition, and 71% attended the referral. The ANC (RR 1.0 95% CI 1.00, 1.01) and hospital delivery rates for complicated pregnancies (RR 1.03 95% CI 0.89, 1.20) did not differ between intervention and control clusters nor did the composite outcome (RR 1.09 95% CI 0.97, 1.23) or its individual components.

CONCLUSIONS

Despite availability of ultrasound at ANC in the intervention clusters, neither ANC nor hospital delivery for complicated pregnancies increased. The composite outcome and the individual components were not reduced.

TWEETABLE ABSTRACT

Antenatal care ultrasound did not improve a composite outcome that included maternal, fetal, and neonatal mortality.

A prospective cause of death classification system for maternal deaths in low and middle-income countries: results from the Global Network Maternal Newborn Health Registry

OBJECTIVE

To describe the causes of maternal death in a population-based cohort in six low- and middle-income countries using a standardised, hierarchical, algorithmic cause of death (COD) methodology.

DESIGN

A population-based, prospective observational study.

SETTING

Seven sites in six low- to middle-income countries including the Democratic Republic of the Congo (DRC), Guatemala, India (two sites), Kenya, Pakistan and Zambia.

POPULATION

All deaths among pregnant women resident in the study sites from 2014 to December 2016.

METHODS

For women who died, we used a standardised questionnaire to collect clinical data regarding maternal conditions present during pregnancy and delivery. These data were analysed using a computer-based algorithm to assign cause of maternal death based on the International Classification of Disease-Maternal Mortality system (trauma, termination of pregnancy-related, eclampsia, haemorrhage, pregnancy-related infection and medical conditions). We also compared the COD results to healthcare-provider-assigned maternal COD.

MAIN OUTCOME MEASURES

Assigned causes of maternal mortality.

RESULTS

Among 158 205 women, there were 221 maternal deaths. The most common algorithm-assigned maternal COD were obstetric haemorrhage (38.6%), pregnancy-related infection (26.4%) and pre-eclampsia/eclampsia (18.2%). Agreement between algorithm-assigned COD and COD assigned by healthcare providers ranged from 75% for haemorrhage to 25% for medical causes coincident to pregnancy.

CONCLUSIONS

The major maternal COD in the Global Network sites were haemorrhage, pregnancy-related infection and pre-eclampsia/eclampsia. This system could allow public health programmes in low- and middle-income countries to generate transparent and comparable data for maternal COD across time or regions.

TWEETABLE ABSTRACT

An algorithmic system for determining maternal cause of death in low-resource settings is described.

Global Network for Women's and Children's Health Research: probable causes of stillbirth in low- and middle-income countries using a prospectively defined classification system

OBJECTIVE

We sought to classify causes of stillbirth for six low-middle-income countries using a prospectively defined algorithm.

DESIGN

Prospective, observational study.

SETTING

Communities in India, Pakistan, Guatemala, Democratic Republic of Congo, Zambia and Kenya.

POPULATION

Pregnant women residing in defined study regions.

METHODS

Basic data regarding conditions present during pregnancy and delivery were collected. Using these data, a computer-based hierarchal algorithm assigned cause of stillbirth. Causes included birth trauma, congenital anomaly, infection, asphyxia, and preterm birth, based on existing cause of death classifications and included contributing maternal conditions.

MAIN OUTCOME MEASURES

Primary cause of stillbirth.

RESULTS

Of 109 911 women who were enrolled and delivered (99% of those screened in pregnancy), 2847 had a stillbirth (a rate of 27.2 per 1000 births). Asphyxia was the cause of 46.6% of the stillbirths, followed by infection (20.8%), congenital anomalies (8.4%) and prematurity (6.6%). Among those caused by asphyxia, 38% had prolonged or obstructed labour, 19% antepartum haemorrhage and 18% pre-eclampsia/eclampsia. About two-thirds (67.4%) of the stillbirths did not have signs of maceration.

CONCLUSIONS

Our algorithm determined cause of stillbirth from basic data obtained from lay-health providers. The major cause of stillbirth was fetal asphyxia associated with prolonged or obstructed labour, pre-eclampsia and antepartum haemorrhage. In the African sites, infection also was an important contributor to stillbirth. Using this algorithm, we documented cause of stillbirth and its trends to inform public health programs, using consistency, transparency, and comparability across time or regions with minimal burden on the healthcare system.

TWEETABLE ABSTRACT

Major causes of stillbirth are asphyxia, pre-eclampsia and haemorrhage. Infections are important in Africa.

Effects of intravenous insulin-like growth factor-I and insulin administration on insulin-like growth factor-binding proteins in the ovine fetus

The insulin-like growth factors (IGF) are important anabolic hormones in the mammalian fetus; their anabolic actions are potentially modulated by alterations in the IGF-binding proteins (IGFBP). We have previously shown that the nutritional state of the fetus affects both IGF-I and the IGFBP concentrations. The present study was designed to determine the effect of alterations in insulin and IGF-I circulating concentrations on the IGFBPs. Because both insulin and IGF-I elicit decreases in glucose and amino acid concentrations, the concentrations of these substrates were clamped during the hormone infusions. Sixteen ovine fetuses were chronically catheterized at approximately 115 days of gestation, and experimental procedures performed at approximately 130 days of gestation. Insulin, IGF-I or both were infused for an 8-h period. Baseline concentrations of hormones and binding proteins were obtained, and concentrations were also obtained at the end of the infusion. Hepatic IGFBP-1 mRNA expression was also determined. Intravenous infusion of IGF-I significantly increased IGF-I concentrations in plasma in the ovine fetus. Intravenous infusion of insulin inhibited hepatic IGFBP-1 gene expression when amino acids and glucose were clamped. In contrast, intravenous infusion of recombinant human IGF-I (rhIGF-I) enhanced hepatic IGFBP-1 gene expression. Neither insulin nor rhIGF-I treatment had an effect on hepatic IGFBP-3 gene expression. Insulin did not alter plasma IGFBP-1 significantly, but it increased IGFBP-3 in plasma. rhIGF-I increased both IGFBP-1 and IGFBP-3 protein levels in plasma. The responses of IGFBP-1 and IGFBP-3 to increased plasma IGF-I and insulin may serve to protect the fetus from exaggerated anabolic effects and to blunt the hypoglycemic potential of circulating IGFs and insulin.

Amino acids do not suppress proteolysis in premature neonates

To determine whether increased amino acid availability can reduce proteolysis in premature neonates and to assess the capacity of infants born prematurely to acutely increase the irreversible catabolism of the essential amino acids leucine (via oxidation) and phenylalanine (via hydroxylation to form tyrosine), leucine and phenylalanine kinetics were measured under basal conditions and in response to a graded infusion of intravenous amino acids (1.2 and 2.4 g. kg(-1). day(-1)) in clinically stable premature (approximately 32 wk gestation) infants in the 1st wk of life. In contrast to the dose-dependent suppression of proteolysis seen in healthy full-term neonates, the endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were unchanged in response to amino acids (297 +/- 21, 283 +/- 19, and 284 +/- 31 micromol. kg(-1). h(-1) for leucine and 92 +/- 6, 92 +/- 4, and 84 +/- 7 micromol. kg(-1). h(-1) for phenylalanine). Similar to full-term neonates, leucine oxidation (40 +/- 5, 65 +/- 6, and 99 +/- 7 micromol. kg(-1). h(-1)) and phenylalanine hydroxylation (12 +/- 1, 16 +/- 1, and 20 +/- 2 micromol. kg(-1). h(-1)) increased in a stepwise fashion in response to graded amino acids. This capacity to increase phenylalanine hydroxylation may be crucial to meet tyrosine needs when exogenous supply is limited. Finally, to determine whether amino acids stimulate glucose production in premature neonates, glucose rate of appearance was measured during each study period. In response to amino acid infusion, rates of endogenous glucose production were unchanged (and near zero).

Glucose and amino acid kinetic response to graded infusion of rhIGF-I in the late gestation ovine fetus

Insulin-like growth factor I (IGF-I) has anabolic effects and is thought to be important in fetal development. The present study was designed to determine the dose response of recombinant human (rh) IGF-I on ovine fetal glucose and amino acid kinetics. Chronically catheterized fetal lambs were studied at 122-127 days gestation. The kinetics of leucine, phenylalanine, and glucose were measured before and during the infusion of rhIGF-I. rhIGF-I was infused into the fetal inferior vena cava at low, medium, or high rates (9.9, 20.1, or 40.2 nmol/h, respectively). A stepwise increase in serum IGF-I was achieved (164 +/- 3, 222 +/- 7, and 275 +/- 5 ng/ml). Insulin concentrations were decreased at the medium and high rhIGF doses. The rate of appearance (Ra) of leucine and phenylalanine and leucine oxidation decreased. Phenylalanine appearance from protein breakdown was decreased, with a maximal suppression of 30% observed at the highest rate of infusion. Glucose Ra was increased at the medium and high doses; other aspects of glucose metabolism were unchanged. The change in both glucose Ra and suppression of proteolysis was significantly correlated to the rhIGF-I infusion rate. It is concluded that rhIGF-I exerts dose-related effects in the ovine fetus, increasing fetoplacental glucose turnover and causing significant suppression of both proteolysis and amino acid oxidation.

Aromatic amino acids are utilized and protein synthesis is stimulated during amino acid infusion in the ovine fetus

The purpose of this study was to determine whether the ovine fetus is capable of increased disposal of an amino acid load; if so, would it respond by increased protein synthesis, amino acid catabolism or both? A further purpose of the study was to determine whether the pathways of aromatic amino acid catabolism are functional in the fetus. Late gestation ovine fetuses of well-nourished ewes received an infusion of Aminosyn PF alone (APF), and Aminosyn PF + glycyl-L-tyrosine (APF+GT) at rates estimated to double the intake of these amino acids. The initial study, using APF, was performed at 126 +/- 1.4 d; the APF+GT study was performed at 132 +/- 1.7 d (term = 150 d). Phenylalanine and tyrosine kinetics were determined using both stable and radioactive isotopes. Plasma concentrations of most amino acids, but not tyrosine, increased during both studies; tyrosine concentration increased only during the APF+GT study. Phenylalanine rate of appearance and phenylalanine hydroxylation increased during both studies. Tyrosine rate of appearance increased only during the APF+GT study; tyrosine oxidation did not increase during either study. Fetal protein synthesis increased significantly during both studies, producing a significant increase in fetal protein accretion. Fetal proteolysis was unchanged in response to either amino acid infusion. These results indicate that the fetus responds to an acute increase in amino acid supply primarily by increasing protein synthesis and accretion, with a smaller but significant increase in amino acid catabolism also. Both phenylalanine hydroxylation and tyrosine oxidation are active in the fetus, and the fetus is able to increase phenylalanine hydroxylation rapidly in response to increased supply.

Increased energy expenditure in infants with cyanotic congenital heart disease

Infants with cyanotic congenital heart disease (CCHD) often have reduced weight gain compared with infants in control groups. Our purpose was to conduct a longitudinal study of energy intake, resting energy expenditure (REE), and total energy expenditure (TEE) of a group of infants with CCHD. We hypothesized that increased REE and TEE and decreased energy intake in these infants would lead to reduced growth. Ten infants with uncorrected CCHD and 12 infants in a control group were studied at 2 weeks of age and again at 3 months. Indirect calorimetry was used to determine REE; the doubly labeled water method was used to determine TEE and intake. At 2 weeks and 3 months of age, infants with CCHD weighed significantly less than infants in the control group. No significant difference was seen in energy intake or REE between groups during either period. TEE was slightly but not statistically increased in the CCHD group at 2 weeks (72.6 +/- 17.4 vs 59.8 +/- 10.9 kcal/kg/d) and significantly increased at 3 months (93.6 +/- 23.3 vs 72.2 +/- 13.2 kcal/kg/d, P </=.03). We conclude that increased TEE but not increased REE is a primary factor in the reduced growth in infants with CCHD.

Effect of rhIGF-I infusion on whole fetal and fetal skeletal muscle protein metabolism in sheep

Insulin-like growth factor I (IGF-I) has been shown to have significant anabolic effects in the regulation of fetal protein metabolism. To investigate the tissue-specific effects of IGF-I on fetal skeletal muscle metabolism, we infused recombinant human (rh) IGF-I directly into the hindlimb of nine chronically catheterized, late-gestation fetal sheep. Substrate balance and amino acid kinetics were measured across the hindlimb and were compared with the effects at the whole body level before and during a 3-h infusion of rhIGF-I into the external iliac artery at 150 microgram/h. Infusion of rhIGF-I resulted in increases in IGF-I concentrations by 2- to 5. 75-fold in the ipsilateral iliac vein and by nearly 3-fold in the abdominal aorta. In the study limb, IGF-I had no effect on protein synthesis (phenylalanine rate of disposal 0.88 +/- 0.13 before vs. 0. 73 +/- 0.19 micromol/min during IGF-I) or breakdown (phenylalanine rate of appearance 0.67 +/- 0.13 before vs. 0.60 +/- 0.17 micromol/min during IGF-I) and did not alter net phenylalanine balance. IGF-I also did not affect hindlimb oxygen or glucose uptake. In contrast, at the whole body level, the rate of appearance of leucine, indicative of fetal protein breakdown, decreased during IGF-I infusion (rate of appearance of leucine 41.1 +/- 3.3 to 37.6 +/- 2.7 micromol/min) as did fetal leucine oxidation (8.4 +/- 0.8 to 6.8 +/- 0.6 micromol/min). There was no change in the umbilical uptake of leucine, and although not statistically significant, fetal leucine accretion increased 2.4-fold. These results provide further evidence that IGF-I promotes fetal protein accretion; however, its site of action is in tissues other than skeletal muscle.

Late gestational vascular disruptions inducing craniofacial anomalies: a fetal lamb model

We report our preliminary observations in six fetal lambs that were surgically manipulated in utero to impede the blood flow of the carotid arteries and their branches, including the laryngeal artery, the anastomotic branch between the vertebral artery and the occipital artery, the auricularis and the transverse facial arteries. Between 115 and 117 days of gestation (term pregnancy 147 days), all ewes were placed under general anesthesia and mechanical ventilation. Their fetuses were exteriorized and catheters were placed in their femoral artery for blood gas sampling. A balloon occluder and a blood flow probe were placed on one internal carotid while the contralateral side was completely ligated. On the third day post surgery, the balloon occluder was inflated three times for 30 minutes each time at 30 minute intervals in the experimental fetuses. PO2, PCO2, pH, lactate and glucose were monitored during the study. At 7 days post occlusion, all animals were sacrificed and tissues were collected. Craniofacial anomalies were obvious in three animals similar to those seen in hemifacial microsomia, Goldenhar syndrome and Pierre-Robin sequence. All three control animals had normal craniofacial structures. This preliminary data suggests that late gestation vascular disruptions may lead to significant craniofacial anomalies, as seen in our animal model.

Determination of the specific activity of sheep plasma amino acids using high-performance liquid chromatography: comparison study between liquid scintillation counter and on-line flow-through detector

A method was developed for the determination of the specific activities of leucine and phenylalanine in plasma using a flow-through scintillation counter coupled with high-performance liquid chromatography components. Results were compared with those obtained from liquid scintillation counting. Differences in the specific activities of leucine and phenylalanine between the two methods were not statistically significant. We concluded that flow-through radioactivity detection can be used for quantitative amino acid assays. However, the minimum activity that can be detected may be prohibitively low in certain applications.

Regulation of fetal amino acid metabolism: substrate or hormonal regulation?

Insulin is regarded as the primary fetal growth-promoting hormone, but direct in vivo experimental data supporting this conjecture are sparse. Data obtained from studies in in vivo, chronically catheterized fetal lambs under a variety of experimental circumstances demonstrate that glucose availability is the primary modulator of fetal protein accretion, via its ability to diminish amino acid catabolism. The ovine fetus is shown to be resistant to insulin-induced suppression of proteolysis, relative to the adult. Data from studies in the human premature infant show that the findings in the ovine fetus are similar to those in the ex utero premature human.

Amino acids suppress proteolysis independent of insulin throughout the neonatal period

To determine how increased amino acid availability alters rates of whole body proteolysis and the irreversible catabolism of the essential amino acids leucine and phenylalanine throughout the neonatal period, leucine and phenylalanine kinetics were measured under basal conditions and in response to intravenous amino acids in two separate groups of healthy, full-term newborns (at 3 days and 3 wk of age). The endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were suppressed equally in both groups and in a dose-dependent fashion (by approximately 10% with 1.2 g x kg(-1) x day(-1) and by approximately 20% with 2.4 g x kg(-1) x day(-1)) in response to intravenous amino acid delivery. Insulin concentrations remained unchanged from basal values during amino acid administration. The irreversible catabolism of leucine and phenylalanine increased in a stepwise fashion in response to intravenous amino acids; again, no differences were observed between the two groups. This study clearly demonstrates that the capacity to acutely increase rates of leucine oxidation and phenylalanine hydroxylation is fully present early in the neonatal period in normal newborns. Furthermore, these data suggest that amino acid availability is a primary regulator of proteolysis in normal newborns throughout the neonatal period.

Nutritional regulation of circulating insulin-like growth factors (IGFs) and their binding proteins in the ovine fetus

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important for fetal and postnatal development, but the regulation of circulating IGFs and IGFBPs has not been as thoroughly investigated in the maternal/fetal unit as in the adult animal where nutrition status plays a regulatory role. We used the chronically-catheterized, late-gestation ovine model and compared circulating IGFs and IGFBPs levels, and hepatic IGF-I mRNA levels. Following a five-day maternal fast, both IGF-I and IGF-II levels were decreased in the maternal and fetal circulation (P < 0.05), accompanied by a decrease in fetal hepatic IGF-I mRNA levels, but the IGFBP2 level was increased and the IGFBP3 level was decreased in maternal circulation, whereas the IGFBP1 level was increased in fetal circulation. In both fed and fasting states, the infusion of glucose (150% of baseline) did not alter IGFs or IGFBPs in either maternal or fetal circulation. To understand the regulation of the endogenous IGF system, rhIGF-I was infused (6.7 nmol/kg fetus/h) into the fetal circulation. While maternal IGFs or IGFBPs remained unchanged, IGF-I infusion into fetal circulation resulted in an increase in IGF-I, a decrease in IGF-II, and an overall increase in the IGFBPs (P < 0.05). Taken together, circulating IGFs and IGFBPs in the ovine fetus are more sensitive to prolonged nutrient deficit than to a brief glucose increase. The nutrition status therefore regulates the IGF system in maternal and fetal circulation which, in turn, may regulate the nutrient utilization for fetal growth.

Effects of circulating IGF-I on glucose and amino acid kinetics in the ovine fetus

To investigate the role of insulin-like growth factor I (IGF-I) in the regulation of fetal metabolism, the kinetics of leucine, phenylalanine, and glucose were assessed in the chronically catheterized ovine fetus (0.85 gestation) before and during infusion of recombinant human IGF-I (rhIGF-I). Substrate kinetics were determined by tracer dilution. rhIGF-I was infused at 6.7 nmol.kg fetus-1.h-1. Fetal insulin and growth hormone concentrations were significantly decreased by 50% during rhIGF-I infusion. Net umbilical glucose uptake was unchanged, and glucose rate of appearance increased in the fed state only. There were no changes in the net umbilical uptakes of leucine or phenylalanine, but the rates of appearance of both declined during rhIGF-I infusion, indicative of decreased fetal protein breakdown (Ra,Leu 45.4 +/- 1.40 to 40 +/- 1.4 mumol/min in the fed state, 43 +/- 1.5 to 37 +/- 1.5 mumol/min in the fasted state; Ra,Phe 10.7 +/- 0.3 to 10.4 +/- 0.3 mumol/min in the fed state and from 10.7 +/- 0.3 to 9.8 +/- 0.3 mumol/min in the fasted state). Leucine oxidation was also decreased (8.90 +/- 0.76 to 6.52 +/- 0.81 mumol/min, P = 0.025), more so in the fasted than the fed state. These results indicate a significant antiproteolytic endocrine effect for IGF-I in the late-gestation mammalian fetus.

Comparison of steady-state diffusion and transit time ultrasonic measurements of umbilical blood flow in the chronic fetal sheep preparation

OBJECTIVE

Our purpose was to measure umbilical blood flow continuously by use of a transit time ultrasonic flow transducer and to compare the blood flow measurements with the steady-state diffusion method in the chronic fetal sheep preparation.

STUDY DESIGN

We compared umbilical blood flow measurements calculated by the steady-state diffusion method with ethanol as the diffusing substance and with the transit time ultrasonic flow transducer placed on the common umbilical artery in five chronically prepared fetal sheep.

RESULTS

There was no statistical difference between measurements of umbilical blood flow measured by the flow transducer versus the steady-state diffusion method, 600 +/- 22 versus 664 +/- 56 ml per minute (mean +/- SEM) (p = 0.23). The mean coefficient of variation within each study was 13.6% for the steady-state diffusion method versus 4.1% for the transit time flow transducer. Umbilical blood flow variance was significantly lower as measured by the flow transducer compared with the diffusion method (p < 0.0001). There were no differences in umbilical blood flow per kilogram or fetal oxygen uptake between the two methods.

CONCLUSION

We conclude that umbilical blood flow can be measured continuously under steady-state conditions by use of a transit time flow transducer. Because of the lower variability in the flow transducer-obtained measurements, we speculate that the flow transducer may differentiate alterations in umbilical blood flow with greater precision in chronic preparations. This may be advantageous for measuring absolute changes in fetal substrate uptake, especially under non-steady-state conditions.

Proteolysis and phenylalanine hydroxylation in response to parenteral nutrition in extremely premature and normal newborns

To determine to what extent intravenous nutrition can reduce proteolysis in very immature and normal newborns, and to assess the capacity of preterm and normal newborns to convert phenylalanine to tyrosine, phenylalanine and leucine kinetics were measured under basal conditions and during parenteral nutrition in clinically stable, extremely premature (approximately 26 wk of gestation) infants and in normal term newborns. In response to parenteral nutrition, there was significantly less suppression (P < 0.001) of endogenous leucine and phenylalanine rate of appearance in extremely premature infants compared with term infants. Phenylalanine utilization for protein synthesis during parenteral nutrition increased significantly (P < 0.01) and by the same magnitude (approximately 15%) in both extremely premature and term infants. Phenylalanine was converted to tyrosine at substantial rates in both extremely premature and term infants; however, this conversion rate was significantly higher (P < 0.05) in extremely premature infants during both the basal and parenteral nutrition periods. These data provide clear evidence that there is no immaturity in the phenylalanine hydroxylation pathway. Furthermore, although parenteral nutrition appears to produce similar increases in protein synthesis in extremely premature and term infants, proteolysis is suppressed much less in extremely premature newborns. The factors responsible for this apparent resistance to suppression of proteolysis in the very immature newborn remain to be elucidated.

Effect of prolonged uterine blood flow reduction on fetal growth in sheep

The purpose of the present investigation was to study the effect of 7 days of uterine blood flow reduction on fetal growth. Reduction in uterine blood flow was accomplished by external occlusion of the terminal aorta in 20 pregnant sheep. Linear growth was monitored daily by means of a crown-rump length measuring device. The deliveries of oxygen, glucose, and lactate to the fetus, as well as their uptakes by the fetus, were determined before and after 7 days of uterine blood flow reduction and correlated with rates of fetal growth. Identical studies were conducted in nine control animals. Uterine blood flow reduction resulted in a significant decrease in fetal oxygen delivery and fetal arterial oxygen content. Linear growth rate decreased by 38% in the occluded animals during hypoxemia. In addition, there was a 20% reduction in daily weight gain in occluded animals compared with controls. There were no differences in the uptakes of oxygen, glucose, and lactate by the fetus. Positive correlations were found between linear growth rate and fetal arterial oxygen content (r2 = 0.25, P = 0.0001) and between linear growth rate and fetal oxygen delivery (r2 = 0.21, P = 0.0006). The correlations between linear growth rate and fetal oxygenation provide strong evidence of the central role of oxygen in the regulation of fetal growth.

Effect of intravenous glucose and lipid on proteolysis and glucose production in normal newborns

To determine whether nonprotein substrate can suppress proteolysis in normal newborns and to assess the effect of this substrate on glucose production, the rates of appearance (Ra) of leucine (reflecting proteolysis) and glucose were measured in healthy 2-day-old full-term newborns during fasting, an intravenous glucose infusion (5.5 mg.kg-1.min-1), an intravenous lipid infusion (2.5 mg.kg-1.min-1), and a combined glucose plus lipid infusion (5.5 mg.kg-1.min-1 glucose + 2.5 mg.kg-1.min-1 lipid). Leucine RA was not reduced from fasting values during any of the substrate infusions. Intravenous lipid infusion alone neither suppressed nor increased glucose production. In contrast, glucose production was nearly completely suppressed (approximately 90%) during intravenous infusions of glucose provided either alone or in combination with lipid; this suppression was achieved at glucose concentrations of approximately 90 mg/dl and insulin concentrations of approximately 6 microU/ml. Thus normal newborns respond to intravenous glucose with sustained nearly complete suppression of glucose production, even at moderate levels of glycemia and at low insulin concentrations; however, nonprotein substrate infusion does not result in suppression of proteolysis. It remains unclear to what extent any potential regulator can suppress proteolysis in this population.

Skeletal muscle proteolysis is reduced in noninsulin-dependent diabetes mellitus and is unaltered by euglycemic hyperinsulinemia or intensive insulin therapy

To assess how noninsulin-dependent diabetes mellitus (NIDDM) and diabetes control may alter whole body and skeletal muscle proteolysis, we measured the rate of appearance (Ra) of phenylalanine (reflecting proteolysis) in the whole body and across the leg (reflecting skeletal muscle), using a constant tracer infusion of [2H5]phenylalanine in the basal state and during high-dose euglycemic hyperinsulinemia in 6 NIDDM and 10 control subjects. Studies were performed in NIDDM subjects 2 weeks after complete withdrawal of antidiabetic treatment and again after intensive insulin therapy. After intensive treatment, significant reductions were measured in hemoglobin A1C, fasting glucose concentrations, and basal hepatic glucose output. In contrast, there was no change after therapy in basal whole body or leg phenylalanine Ra. Compared with that of controls, whole body phenylalanine Ra was significantly higher and leg phenylalanine Ra significantly lower in NIDDM subjects. During euglycemic hyperinsulinemia, whole body phenylalanine Ra was significantly suppressed (approximately 15%) below basal values before and after therapy in NIDDM subjects and similarly suppressed in control subjects. However, in NIDDM subjects, euglycemic hyperinsulinemia did not reduce leg phenylalanine Ra below basal values either before or after therapy, whereas hyperinsulinemia resulted in a 42% suppression of leg phenylalanine Ra in controls. We conclude that 1) the clear improvement in glucose metabolism produced by intensive insulin therapy in NIDDM is not accompanied by changes in whole body or skeletal muscle proteolysis; 2) skeletal muscle proteolysis is reduced even though whole body proteolysis is increased in NIDDM subjects compared with controls; and 3) although a high-dose systemic infusion of insulin significantly reduces whole body proteolysis in both NIDDM and control subjects, skeletal muscle proteolysis is suppressed only in controls. We speculate that in NIDDM, high basal insulin concentrations (approximately 200 pmol/L, unaltered by therapy) maximally suppress skeletal muscle proteolysis, and therefore higher insulin concentrations produce no additional suppression in skeletal muscle.

Sepsis in asymptomatic term newborns delivered of antibiotic-treated mothers

This study was undertaken to assess the incidence of culture-proved sepsis in term infants without symptoms born to mothers receiving intrapartum antibiotics and to determine the usefulness of the immature neutrophil: total neutrophil (I:T) ratio in the initial evaluation of these infants. A retrospective chart review was made of 103 infants born during a 3-year period. There was one positive blood culture and two positive cerebrospinal fluid cultures in three different patients; all three isolates were considered contaminants and all patients remained without symptoms. In spite of the lack of culture-proved sepsis and clinical illness, more than 50% of the initial I:T ratios were greater than the usually accepted upper limit of normal (that is, 0.16). We conclude that the incidence of sepsis in this population is very low and the initial I:T ratio is not useful as a predictive tool in term newborns without symptoms.

Effect of enteral versus parenteral feeding on leucine kinetics and fuel utilization in premature newborns

To determine whether the route of nutrient delivery affects whole-body protein kinetics and fuel utilization, eight premature newborns were studied during both a 4-h period of enteral intake and a 4-h period of parenteral nutrition. The kinetics of the essential amino acid leucine were measured using a constant tracer infusion of 1-13C-leucine, and fuel utilization and energy expenditure were assessed by respiratory calorimetry. All leucine kinetic parameters were similar during enteral or parenteral nutrition (in mean +/- SD mumol/kg/h, flux = 233 +/- 51 enteral versus 258 +/- 42 parenteral, leucine from protein breakdown = 177 +/- 50 enteral versus 200 +/- 41 parenteral, leucine oxidation = 57 +/- 26 enteral versus 63 +/- 20 parenteral, and leucine used for protein synthesis = 176 +/- 63 enteral versus 196 +/- 50 parenteral). In addition, overall rates of energy expenditure (approximately 52 kcal/kg/d) and pattern of fuel utilization (approximately 70% carbohydrate, 13% fat, 17% protein) were unaltered by the route of feeding. Thus, as reflected by leucine kinetics, overall rates of protein turnover, synthesis, oxidation, and breakdown as well as energy expenditure and fuel utilization are similar when nutrition is provided to premature newborns by either the enteral or parenteral route. These results suggest that short-term provision of parenteral nutrition may be able to substitute appropriately for enteral intake, at least with regard to the utilization of one essential amino acid and the overall pattern of fuel utilization.

Effectiveness of two feeding methods in improving energy intake and growth of infants with cleft palate: a randomized study

OBJECTIVE

To compare two feeding methods advocated for infants with cleft palate: (a) a squeezable plastic container with a narrow, long crosscut nipple (squeezable cleft palate nurser); and (b) a standard nipple with a crosscut (crosscut nipple). The effectiveness of a nutrition intervention protocol for these infants was also documented.

DESIGN

Thirty-one infants (median age = 15 days) were randomized to one of two feeding methods (18 infants, squeezable cleft lip/palate nurser; 13 infants, crosscut nipple) within sex (21 boys, 10 girls) and palatal defect (22 cleft lip and palate, 9 isolated cleft palate) categories. The intervention included feeding technique instructions, nutrition counseling at each clinic visit, use of the same 20 kcal/oz standard formula for 12 months, and introduction of infant and soft table foods at 6 months. Four-day food records and growth data were obtained.

MAIN OUTCOME MEASURES

Mean energy and protein intakes at 3 and 6 months of age and growth measurements during the first 18 months of life were obtained.

STATISTICAL ANALYSES

A repeated measures analysis of variance for intakes was performed with time as the repeated measure and feeding method as the covariable. Similar analyses were completed for growth measures with sex and feeding method as covariates.

RESULTS

Mean energy intake at 3 and 6 months of age (P = .24) and growth measurements during the first 18 months of life (P values: weight gain [grams per day], .73; weight, .21; length, .07; head circumference, .18; triceps and subscapular skinfolds and mid-arm circumference, .47, .48, and .69, respectively) were not significantly different. Both feeding methods were effective in supporting normal growth.

APPLICATIONS

With adequate instruction related to the use of either feeding technique and close nutrition follow-up early in infancy, a dietitian or other health care practitioner may advise the use of either feeding method. These data support the need for feeding and nutrition education and early nutrition intervention.

Intravenous glucose suppresses glucose production but not proteolysis in extremely premature newborns

To ascertain whether the inability to suppress glucose production and increase glucose utilization in response to glucose infusion is an inherent characteristic of immature individuals, we determined glucose rate of appearance (R(a)) in minimally stressed, clinically stable, extremely premature infants (approximately 26-wk gestation) at two glucose infusion rates (6.2 +/- 0.4 and 9.5 +/- 0.5 mg/kg per min). We also assessed whether an increase in glucose delivery suppresses proteolysis by measuring the R(a) of phenylalanine and leucine. Glucose R(a) (and utilization) increased significantly at the higher glucose infusion rate (7.9 +/- 0.5 vs. 9.8 +/- 0.6 mg/kg per min). Glucose production persisted at the lower glucose infusion rate but was suppressed to nearly zero at the higher rate (1.7 +/- 0.5 vs. 0.3 +/- 0.1 mg/kg per min). Proteolysis was unaffected by the higher glucose infusion rate as reflected by no change in the rates of appearance of either phenylalanine (96 +/- 5 vs. 95 +/- 3 mumol/kg per h) or leucine (285 +/- 20 vs. 283 +/- 14 mumol/kg per h). Thus, clinically stable, extremely premature infants suppress glucose production and increase glucose utilization in response to increased glucose infusion, demonstrating no inherent immaturity of these processes. In contrast, increasing the rate of glucose delivery results in no change in whole body proteolysis in these infants. The regulation of proteolysis in this population remains to be defined.

Increased fetal glucose concentration decreases ovine fetal leucine oxidation independent of insulin

Fetal leucine oxidation rate is elevated during fasting of the ewe. Euglycemic hyperinsulinemia causes the leucine oxidation rate to decline. However, it is unclear whether this is a direct effect of insulin or is secondary to increased insulin-mediated glucose utilization. To better delineate the mechanism of decreased oxidation, we suppressed fetal insulin secretion by somatostatin infusion. Glucose was infused at a variable rate to achieve glucose concentrations 125 and 150% of basal. Leucine rate of appearance (Ra) was determined by infusion of [15N, 1-13C]leucine. Fraction of leucine appearance oxidized was determined by [1-14C]leucine infusion and determination of fetal 14CO2 excretion. Each fetus was studied during ad libitum maternal feeding and after a 5-day complete maternal fast. Changes were noted in fetal leucine oxidation, which declined from 8.4 +/- 1.2 to 5.0 +/- 0.8 mumol/min in the fed state during glucose infusion. Basal leucine oxidation was elevated during fasting (11 +/- 1.5 mumol/min, P < 0.05) and declined to 8.0 +/- 1.4 mumol/min during glucose infusion (P = 0.056). Leucine carbon Ra was unchanged by fasting and by glucose infusion; leucine nitrogen Ra declined in the fed state only. Leucine oxidation was inversely correlated with glucose concentration (oxidation = 12-0.26 x glucose concentration, r = 0.42, P = 0.004). Leucine oxidation was not correlated with insulin concentration (r = 0.2). Changes in fetal glucose concentration may alter the pattern of utilization of essential amino acids, independent of changes in insulin and insulin-mediated glucose utilization rate.

Measurement of nutrient intake by deuterium dilution in premature infants

To assess whether a simple nonrestrictive method of determining nutrient intake could be applied to premature infants, we compared actual measured formula intake during a 7-day period with intake calculated from deuterium dilution in 13 hospitalized, growing, premature newborn infants. An oral dose of deuterium oxide (D2O) was administered, and urine samples were analyzed by deuterium nuclear magnetic resonance spectrometry for D2O concentration. Using an exponential model, we calculated formula intake from the decline in D2O concentration during the 7-day study period. Intake as assessed by the deuterium model correlated well with actual intake (r = 0.93; p < 0.001). However, because the deuterium dilution model measures both dietary and nondietary water intake (metabolic and cutaneous water influx), deuterium dilution-derived intake exceeded actual intake by 25 +/- 18 ml/kg per day (16% +/- 11%). When corrections were applied to account for nondietary water intake, deuterium dilution-derived nutrient intake (160 +/- 30 ml/kg per day) closely approximated actual intake (155 +/- 17 ml/kg per day). If corrections are made for nondietary water intake, the deuterium dilution method may be a useful nonrestrictive method of measuring nutrient intake in a variety of neonatal populations.

Blood ammonia concentration in cord blood during pregnancy

In vivo studies in several animal species and in vitro studies of human placenta suggest that ammonia is produced within the uteroplacenta and released into the fetal and maternal circulations. Furthermore, the fetal blood ammonia levels in sheep have been found to be significantly greater than maternal levels and inversely correlated with gestational age. Our present study had two main goals: first, to assess whether ammonia may be produced in the human placenta and taken up by the fetus and second, to determine if the fetal blood ammonia levels are greater than maternal and inversely correlated to gestational age. We measured the blood concentrations of ammonia by obtaining both umbilical venous (UV) and arterial (UA) samples obtained from doubly clamped sections of umbilical cord at the time of delivery. Blood gases and glucose were also measured on each sample. Samples were obtained at 96 deliveries (70 vaginal, 26 cesarean section, 18/26 cesarean deliveries not in labor). The deliveries were separated into two groups. Group A included all deliveries, both vaginal and cesarean section, while Group B consisted of only cesarean section prior to onset of labor. The mean gestational age for all deliveries was 38.4 weeks +/- 2.95 (S.D.) with a range of 25-43 weeks of gestation. There was no significant relationship between the fetal ammonia levels and gestational age in either group. In both groups A and B, the UA ammonia concentrations were significantly higher than the paired UV ammonia levels (UV-UA: Group A: -10.00 +/- 17.6, Group B: -9.3 +/- 12.6).

CONCLUSION

These data show no correlation between fetal ammonia levels and gestational age.(ABSTRACT TRUNCATED AT 250 WORDS)

Leucine kinetics after a brief fast and in response to feeding in premature infants

To examine how feeding affects changes in leucine and protein metabolism, leucine kinetics were determined in nine preterm infants (32 +/- 2 wk gestation; mean +/- SD) after a brief fast and again during hourly feedings. Rates of leucine oxidation were similar during the fasting and feeding periods (31 +/- 4 vs 37 +/- 6 mumol.kg-1.h-1; mean +/- SE). The nonoxidative disposal rates of leucine (a reflection of protein synthesis) were also similar during both periods (228 +/- 20 vs 205 +/- 10 mumol.kg-1.h-1; mean +/- SE). In contrast, the rates of leucine release from endogenous protein (an indication of protein breakdown) were significantly reduced by feeding (259 +/- 23 vs 185 +/- 11 mumol.kg-1.h-1; mean +/- SE, P = 0.02). A significant positive correlation was demonstrated between the fasting rate of leucine release from endogenous protein and the degree of suppression produced by feeding (r2 = 0.796, P = 0.001). Conversely, a significant inverse correlation was shown between the nonoxidative disposal rate of leucine during fasting and the increase in response to feeding (r2 = 0.848, P < 0.001). These data suggest that premature infants respond to feeding after a brief fast by suppressing protein breakdown, rather than by increasing protein synthesis, and changes in protein metabolism produced by feeding in premature newborns may be influenced by the prevailing rates of protein breakdown and synthesis during fasting.

Effect of hyperinsulinemia on ovine fetal leucine kinetics during prolonged maternal fasting

The primary effect of insulin on whole body protein metabolism in postnatal life is to reduce proteolysis. To assess the role of insulin in the regulation of protein metabolism in prenatal life, leucine kinetics were determined in the ovine fetus at baseline and in response to hyperinsulinemia. These measurements were made in each fetus in two different maternal states: ad libitum maternal feeding and after a 5-day maternal fast. Maternal fasting resulted in significant increases in baseline fetal leucine rate of appearance (Ra; 51.9 +/- 16.7 vs. 37.3 +/- 3.6 mumol/min, P < 0.05) and leucine oxidation (30.1 +/- 8.9 vs. 8.8 +/- 2.2 mumol/min, P < 0.05). Hyperinsulinemia, which was associated with significant increases in fetal glucose utilization, did not affect total fetal leucine R(a) or leucine release from fetal proteolysis in either maternal state. Under well-fed maternal conditions, hyperinsulinemia produced no changes in the fetal oxidative or nonoxidative disposal of leucine. In contrast, during maternal fasting, hyperinsulinemia reduced fetal leucine oxidation (11.0 +/- 3.7 vs. 31.1 +/- 8.9 mumol/min, P < 0.05) and increased the nonoxidative disposal of leucine (35.4 +/- 4.0 vs. 19.0 +/- 6.1 mumol/min, P < 0.05). This resulted in a change in the fetal leucine accretion rate from negative to positive (-20.9 +/- 7.5 vs. 7.5 +/- 6.7 mumol/min, P < 0.05). These results suggest that, under conditions of restricted maternal substrate intake, fetal hyperinsulinemia and the attendant increase in fetal glucose utilization are associated with increased protein synthesis rather than decreased protein breakdown, thereby improving fetal leucine carcass accretion.

Proteolysis in skeletal muscle and whole body in response to euglycemic hyperinsulinemia in normal adults

To simultaneously assess the relative antiproteolytic effect of insulin on both skeletal muscle and in the whole body, phenylalanine rates of appearance (Ra; reflecting proteolysis) were measured across the leg (reflecting skeletal muscle) and in the whole body, utilizing a constant tracer infusion of [2H5]phenylalanine in the basal state and during euglycemic hyperinsulinemia (2,600 microU/ml) in seven normal adults. Phenylalanine Ra in the leg was significantly decreased during hyperinsulinemia (6.11 +/- 0.83 vs 3.59 +/- 0.70 mumol/min, P less than 0.001). In contrast, leg phenylalanine rate of utilization (Rd) was not significantly changed (4.88 +/- 0.77 vs. 3.86 +/- 0.92 mumol/min). Phenylalanine Ra in the whole body was significantly decreased during hyperinsulinemia (49.4 +/- 2.2 vs. 41.9 +/- 2.3 mumol/min, P less than 0.001). However, phenylalanine release was suppressed to a significantly greater degree in release was suppressed to a significantly greater degree in the leg than in the whole body during hyperinsulinemia (43 +/- 7 vs. 15 +/- 2%, P less than 0.01). These results suggest that insulin suppresses proteolysis in the whole body and in skeletal muscle, even in the face of hypoaminoacidemia. In addition, the substantially greater degree of suppression of proteolysis by insulin in skeletal muscle compared with the whole body suggests that, at least under these conditions, insulin may have a greater antiproteolytic effect on skeletal muscle compared with other tissues.

Effects of glucose infusion on leucine transamination and oxidation in the ovine fetus

During fasting of the ewe, the rate of amino acid oxidation by the ovine fetus increases substantially. We hypothesized that the increase in amino acid oxidation derived mainly from reduced protein synthesis. We further hypothesized that fetal glucose supplementation would result in diminished amino acid oxidation. To test these hypotheses, nine ovine fetuses were infused with [15N,1-13C]leucine to determine the rates of leucine appearance and disposal. Simultaneously, the fetal uptake of leucine was determined. Animals were studied in the fed and fasted state. After baseline measurements, glucose was infused into the fetal inferior vena cava at a rate estimated to match the fetal glucose uptake. Results of these studies indicate that leucine nitrogen flux, leucine carbon flux and fetal leucine uptake were constant. Leucine oxidation was increased by 50% in the fasted state (6.3 versus 13.4 mumol/min); glucose infusion resulted in a 25% decline in oxidation (to 10.4 mumol/min) in the fasted state, but had no effect in the fed state. Mean leucine umbilical uptake during fasting was 9.3 mumol/min, 4.1 mumol/min less than leucine oxidation. These data suggest that leucine (and potentially other amino acids) may be in negative balance during maternal fasting, and can be spared by supplementation of the fetus with exogenous glucose.

Reduction of neonatal mortality after multiple doses of bovine surfactant in low birth weight neonates with respiratory distress syndrome

To determine if outcomes of low birth weight neonates with respiratory distress syndrome can be improved by the administration of multiple doses of bovine surfactant, we conducted two identical multicenter, controlled trials, and the results were combined for analysis. Seven hundred and ninety-eight neonates weighing 600 to 1750 g at birth who had developed respiratory distress syndrome within 6 hours of birth were assigned randomly to receive either 100 mg of phospholipid/kg of Survanta, a modified bovine surfactant (n = 402), or a sham dosing procedure (n = 396). Neonates whose respiratory distress persisted could be given up to three more doses, with all doses to be given in the first 48 hours after birth. Dosing was performed by investigators not involved in the clinical care of the neonates; nursery staff were kept blinded as to the treatment assignment. Fewer Survanta-treated neonates died of any cause (18.4% vs 27.3%, P = .002), died of respiratory distress syndrome (9.0% vs 20.3%, P less than .001), and either died or developed bronchopulmonary dysplasia due to respiratory distress syndrome (51.2% vs 64.6%, P less than .001). Neonates who received Survanta also had greater improvement in their oxygenation and ventilatory status from baseline to 72 hours than did control neonates. Survanta-treated neonates were at lowered risk for developing pulmonary interstitial emphysema (18.6% vs 39.3%, P less than .001) and other pulmonary air leaks (11.5% vs 25.9%, P less than .001). We conclude that multiple doses of Survanta given after diagnosis of respiratory distress syndrome reduce mortality and morbidity.

Ovine fetal and maternal glycogen during fasting

The present study was undertaken to assess the role of hepatic glycogen metabolism in fetal and maternal glucose homeostasis during a prolonged fast in the pregnant ewe. A control fed group of 13 ewes and 16 fetuses were compared to a 5-day-fasted group of 13 ewes and 17 fetuses, studied at 125 days gestation (term = 147 days). Tissue samples were obtained during pentobarbital anesthesia and frozen in liquid nitrogen. Protein, glycogen, active phosphorylase and total phosphorylase activity were determined. Fetal weight (3.61 vs. 2.86 kg) was decreased in the fasted group (p less than 0.001) while fetal hepatic glycogen was unchanged (59.8 vs. 52.4 mg/g tissue). Maternal liver glycogen decreased during fasting (38.2 vs. 4.0 mg/g tissue, p less than 0.001). Fetal active phosphorylase and total phosphorylase did not change between fed and fasted states (fed active phosphorylase 398 vs. fasted 441 and fed total phosphorylase 510 vs. fasted 574 mumol/h/g tissue). The maternal active phosphorylase and total phosphorylase decreased between fed and fasted (active phosphorylase 690 vs. 238 and total phosphorylase 981 vs. 599 mumol/h/g tissue, p less than 0.001). During fasting, the pregnant ewe depletes her hepatic glycogen stores, associated with a reduction in glycogen catabolizing enzyme activity. The fetus maintains a relatively large glycogen catabolizing enzyme activity, a relatively large glycogen reserve and substantial phosphorylase activity.

Effect of fasting on uteroplacental amino acid metabolism in the pregnant sheep

In the fed state, the net utilization of most amino acids by the ovine uteroplacental unit (defined as uterine uptake minus umbilical uptake) is zero. This study was to determine if this is true for the fasted pregnant ewe also, when uteroplacental glucose uptake is diminished. Glucose and amino acid concentrations were determined in 9 pregnant ewes across the uterine and umbilical circulations. Uterine and umbilical blood flows were determined by the steady state antipyrine diffusion method, and net uptakes across each circulation calculated by application of the Fick principle. Five amino acids were found to have a consistently greater uterine uptake than umbilical uptake. In addition, glutamate had a negative net umbilical uptake coupled with no net uterine uptake. Fasting resulted in an increase in the differences between the respective uptakes for all five amino acids. No additional amino acids were found to have disparate uptakes than were seen in the fed state. Umbilical glutamate uptake became less negative during fasting, but the difference between the uterine and umbilical circulations remained unchanged, as the uterine circulation took up glutamate during fasting. The umbilical circulation took up alpha-ketoisocaproate 0.626 +/- 0.18, fed), and the uptake was increased during fasting (1.8 +/- 0.6). These findings suggest that the branched chain amino acids and glutamine are utilized by the ovine uteroplacenta to a greater degree than are most other amino acids, and at increased rates during fasting of the ewe. These amino acids, through deamination, may be the source of uteroplacental ammonia production, as well as serving as an energy substrate when glucose supply is limited.

Contribution of low-molecular-weight compounds to the fecal excretion of carbohydrate energy in premature infants

It was hypothesized that low-molecular-weight products of carbohydrate fermentation would contribute only a small percentage to the total fecal excretion of nonfat, nonnitrogenous energy (carbohydrate energy) in premature infants. Infants born at 28-32 weeks' gestation who were 2-4 weeks of age were randomized to receive a formula with lactose as the sole carbohydrate (n = 7) or the same formula with 50% of the carbohydrate as glucose polymer (n = 8). The percent contribution (X +/- SD) to total carbohydrate energy of sugars (glucose, galactose, lactose, glucose polymer), short-chain fatty acids (acetate, propionate, butyrate, isobutyrate, valerate, and isovalerate), and D- and L-lactate was 9.4% +/- 2.9% for the 15 subjects and was not significantly different between groups. The percent contribution of all four sugars was 5.8% +/- 1.7% and did not differ between the two groups. Doubling the lactose intake resulted in significant increases in fecal excretion (kilocalories per kilogram per day) of acetate (77% increase; P = 0.03), total short-chain fatty acids (54%; P = 0.04), and galactose (188%; P = 0.03). These data suggest that as much as 90% of fecal carbohydrate energy may be in the form of large-molecular-weight compounds, presumably bacterial in origin.

Exogenous adenine nucleotides replete endothelial cell adenosine triphosphate after oxidant injury by adenosine uptake

We studied the ability of human umbilical vein endothelial cells to recover from oxidant-induced ATP depletion. When endothelial cell ATP levels were depressed to 0.93 +/- 0.14 pmol/micrograms protein (compared with 4.96 +/- 0.6 pmol/micrograms protein in control cells) by hydrogen peroxide generated with 25 mU/ml glucose-glucose oxidase over 45 minutes, ATP levels returned to 1.73 +/- 0.21 pmol/micrograms protein during a 3-hour recovery period after oxidant injury ceased. When 25 microM ATP, ADP, AMP, or adenosine was added to the recovery media, intracellular ATP was significantly (p less than 0.001) increased to greater than 4.4 pmol/micrograms cell protein for each metabolite. HPLC of supernatants from oxidant-injured endothelial cells incubated with ATP, ADP, and AMP demonstrated extracellular metabolism of the adenine nucleotides to adenosine. When adenosine transport was inhibited with dipyridamole and nitrobenzylthioinosine, recovery of intracellular ATP by exogenous ATP, ADP, AMP, and adenosine was significantly (p less than 0.001) inhibited. Such cells were intact, as demonstrated by lack of LDH release. When oxidant stress was prolonged to 90 minutes, ATP depletion was irreversible, regardless of exogenously supplied adenosine; such cells demonstrated loss of cell integrity as demonstrated by release of intracellular LDH. Our results demonstrated that exogenous adenine nucleotides enhance recovery of oxidant-induced ATP depletion through metabolism to adenosine and subsequent adenosine uptake. Prolonged oxidant injury resulted in irreversible ATP depletion and loss of cell integrity that was not altered by exogenously supplied adenosine.

Daily sequential changes in plasma atrial natriuretic factor concentrations in mechanically ventilated low-birth-weight infants. Effect of surfactant replacement

Plasma atrial natriuretic factor (ANF) concentrations are elevated in mechanically ventilated infants. To test the hypothesis that changes in pulmonary compliance affect ANF concentration, we measured plasma ANF concentrations sequentially in low-birth-weight, ventilated infants who either received surfactant replacement or placebo on day 1. ANF concentrations were elevated as compared to adult controls on day 1 and increased significantly on days 2 and 3 before declining. Day 5 concentrations were not different from day 1. Several infants had ANF concentrations greater than 1,280 pg/ml on days 2-4. There were no significant differences in ANF concentrations between surfactant-treated and non-treated infants on any day. ANF concentrations increased in parallel with changes in salt and water balance, but no significant relationships were apparent between absolute ANF concentrations and parameters of salt and water balance. The results suggest that ANF secretion is elevated in infants with pulmonary disease. While the temporal relationship between the initial rise in ANF concentration and increase in salt and water excretion suggest that ANF is involved in this diuresis, the role it may play is unclear from the present data.

Effect of pH on fecal recovery of energy derived from volatile fatty acids

We assessed the effect of pH on volatilization of short-chain fatty acids during lyophilization. Acetic, propionic, valeric, and butyric acids were added to a fecal homogenate in amounts sufficient to raise the energy density by 18-27%. Fecal homogenate samples were either acidified (pH 2.8-3.2), alkalinized (pH 7.9-8.7), or left unchanged (4.0-4.8) prior to lyophilization and subsequent bomb calorimetry. Alkalinizing the fecal samples prevented the 20% loss of energy derived from each of these volatile fatty acids observed in samples either acidified or without pH adjustment. These data suggest that in energy balance studies involving subjects with active colonic fermentation, fecal samples should be alkalinized prior to lyophilization and bomb calorimetry.

Dietary carbohydrate assimilation in the premature infant: evidence for a nutritionally significant bacterial ecosystem in the colon

Carbohydrate energy absorption and breath hydrogen concentration were measured in 12 premature infants 28-32 wk gestational age and 2-4 wk postnatal age. Each of two groups of six infants were randomly assigned to receive one of two formulas that differed only in carbohydrate source: 100% lactose (LAC) or 50% lactose: 50% glucose polymer (LAC + GP). In 11 infants the peak breath hydrogen concentration suggested extensive colonic fermentation (range 44-239 ppm/5% CO2 or 44-239 microL/L per 50 mL/L CO2). An approximate 100% increase in lactose intake in the LAC group was associated with a similar increase in breath hydrogen concentration at 30, 60, and 120 min. None of the infants exhibited diarrhea or vomiting or developed delayed gastric emptying. Carbohydrate energy absorption (mean +/- SD) was, respectively, 86 +/- 5% and 91 +/- 3% in the LAC and the LAC + GP groups (p greater than 0.05). Thus, colonic bacterial fermentation may be critical to energy balance and to the prevention of osmotic diarrhea in premature infants fed lactose.

Nitrogen flux across ovine maternal and fetal hindquarters during fasting

Nitrogen flux across the hindquarters of fetal and maternal sheep (n = 15) was determined during normal feeding and following 5 days of maternal fasting. Arterial and venous whole blood concentrations of free amino acids, ammonia and oxygen were measured entering and exiting the hindquarters. Further, the DNA, protein and nitrogen contents of the hindlimb skeletal muscle of the fetus were determined in the fed state and following the 5-day fast. Results of these studies indicate that maternal and fetal hindlimb metabolism differ during fasting. There is a net efflux of alanine, glutamine and total nitrogen from the maternal hindquarters following 5 days of fasting. The fetus also releases glutamine and alanine from the hindquarters during the fast, presumably as potential energy substrate. However, nitrogen balance across the fetal hindquarter remains positive as a result of increased positive arteriovenous differences for other amino acids (particularly leucine and isoleucine). The concentrations of DNA, protein and nitrogen in fetal skeletal muscle remain unchanged during fasting. These data indicate that, whereas the mother undergoes protein catabolism and net nitrogen loss from the hindquarter during fasting, the fetus maintains a positive nitrogen balance across the hindquarter.

Effects in premature infants of normalizing breath H2 concentrations with CO2: increased H2 concentration and reduced interaliquot variation

Interval sampling of expired breath samples from the anterior nares is a feasible and noninvasive method for detecting elevated breath H2 and thus colonic carbohydrate fermentation, especially in nontherapeutic research studies of healthy premature infants. However, there may be a risk of falsely low breath H2 concentration and an unacceptable experimental error due to contamination with room air as well as with dead space air. We studied ten premature infants (28-32 week gestational age and 2-4 weeks postnatal age) who were receiving either a proprietary formula containing equal proportions of lactose and glucose polymer, or a similar formula in which lactose was the sole carbohydrate. In 70 breath samples (obtained 30-180 min after feeding) we assessed the coefficient of variation in breath hydrogen concentration among three aliquots obtained over a 3-5 min interval. Breath was collected from the anterior nares. The interaliquot coefficient of variation averaged 11% when expressed as parts per million per 5% CO2, compared to 19% when expressed as parts per million (Wilcoxon, p less than 0.001). Mean breath hydrogen concentration at each time period using the former method (parts per million per 5% CO2) was about 100% higher than when using the latter method. Although ventilation rate can alter alveolar CO2, normalizing for CO2 concentration reduces a major source of experimental error.

Branched-chain amino acid carbon and nitrogen arteriovenous concentration differences across the ovine fetal hindlimb

During fasting, branched-chain amino acids (BCAA) are thought to be major sources of nitrogen for myocyte synthesis of alanine (Ala) and glutamine (Gln), as well as possible sources of carbon skeleton for Gln synthesis. To study the relationships between Ala, Gln, and BCAA, we utilized the chronic fetal lamb preparation and measured arteriovenous concentration differences of Ala, Gln, BCAA, and branched-chain alpha-keto acids across the fetal hindlimb. Studies were performed when the ewe was fed and repeated after 1 and 5 days of complete maternal fasting. Ala and Gln are released from fetal hindquarters during fasting (arteriovenous -9.6 +/- 5 and -8.8 +/- 4.1 mumol/liter), while arteriovenous differences for BCAA simultaneously increase by 65% as compared to the fed state. During fasting, total nitrogen exiting fetal hindlimb as Ala and Gln equals nitrogen entering as BCAA. Branched-chain alpha-keto acids are released from fetal hindquarters during the fed state as well as after 1 day of fasting; at 5 days of fasting only keto-isovalerate had a net negative arteriovenous difference. In all cases, the release was much smaller than the entry of the corresponding amino acid, as determined by simultaneously measured arteriovenous concentration differences. These results indicate: Ala and Gln are released from fetal hindlimb, as in postnatal animals, during fasting, shuttling nitrogen and carbon to liver and/or other tissues. There is negligible movement of BCAA carbon as the branched-chain alpha-keto acids from hindlimb to other tissues in the fetus. BCAA carbon taken up is utilized within the hindquarters. It may be used for tissue synthesis, as an energy source, or possibly for Gln synthesis.

Effect of maternal fasting on ovine fetal and maternal branched-chain amino acid transaminase activities

Activities of branched-chain amino acid transaminase were assayed in maternal skeletal muscle, liver and fetal skeletal muscle, cardiac muscle, liver, kidney and placenta obtained from fed and 5-day-fasted late gestation ewes. Very high activities were found in placenta; fetal skeletal muscle also had high activity. Fetal brain had intermediate activity, followed by cardiac muscle and kidney. Fetal liver possessed negligible activity. Activities were low in both maternal liver and skeletal muscle. Trends were seen for fasting to increase activities in fetal placenta, skeletal muscle, brain, kidney, heart and maternal liver, but these changes were statistically significant only for fetal brain and placental tissue. Fetal skeletal muscle activity was 100 times that of maternal skeletal muscle. These data imply differences in the metabolism of the branched-chain amino acids by fetal and adult ruminants and expand the thesis that branched-chain amino acids are important to the metabolism of the ovine fetus.

Parental recall of infant medical complications and its relationship to delivery method and education level

Since relatively little is known as to why parents find it difficult to recognize when their high-risk infant ceases to be ill, this investigation examined parental reports of infant complications and the relationship these reports had with parental education level and method of delivery. Using a questionnaire format, 60 parents reported complications their infants experienced during NICU (neonatal intensive care unit) hospitalization. Maternal and paternal reports were comparable, although both significantly differed from actual diagnoses; parents underreported their infant's complications. Reported complications were not related to parental education level but were associated with method of delivery. Parents of Caesarean-section (C-section) infants identified a significantly smaller percentage of complications than did parents of vaginally delivered babies. It is suggested that (1) medical caregivers have the potential for helping parents more fully comprehend infant complications, (2) supplemental communication methods may be necessary for the task in (1), and (3) information communicated to parents may need to incorporate the current findings about parental education level and delivery method.

Changes in ovine fetal hindlimb amino acid metabolism during maternal fasting

The flux of various substrates across the ovine fetal and maternal hindlimbs was measured in the fed state and after 5 days of maternal fasting. Whole blood concentrations of glucose, oxygen, ammonia, and six amino acids (glutamate, glutamine, alanine, valine, isoleucine, and leucine) were determined in the fetal and maternal femoral artery and distal inferior vena cava in 15 chronic animal preparations. During fasting the fetal arterial glucose concentration fell by 40% (from 0.828 to 0.494 mM), and the arteriovenous concentration difference decreased by 30% (from 0.148 to 0.099 mM). Similar changes were noted in maternal blood. Fetal oxygen concentrations remained similar between the fed and fasted state, and the fetal arteriovenous oxygen concentration difference increased slightly from 0.861 to 1.02 mM. The glucose oxygen quotient decreased in the fetus from 1.20 to 0.621. In addition, significant changes occurred in the net balance of several amino acids during the fasted state. Both alanine and glutamine, which demonstrated a positive uptake by the fetal hindlimb during the fed state, showed a substantial efflux from the fetal hindlimb during the fasting period. The fetal arteriovenous concentration difference of the branched-chain amino acids (leucine, isoleucine, and valine) increased significantly during fasting. These observations are consistent with the hypothesis that the ovine fetus adapts to a diminished supply of glucose from the mother by enhanced amino acid catabolism and, possibly, proteolysis with subsequent release of gluconeogenic precursors in the form of alanine and glutamine.

Outcome of high-risk neonates with ventriculomegaly

The authors evaluated 89 infants who had had computed tomography of the head and who were followed-up for a minimum of one year. In a large proportion with moderate ventriculomegaly spontaneous stabilization or regression occurred, with normal developmental outcome in a high percentage of cases. However, there was a statistically significant trend toward lower developmental scores as ventricular size increased. Many infants with ventricular enlargement will not develop progressive hydrocephalus, but their cognitive and psychomotor development may be affected.