Ovulation induction and small for gestational age neonates in twin pregnancies

OBJECTIVE

To compare the incidence of small for gestation age (SGA) neonates in twin gestations conceived by ovulation induction or in vitro fertilization with that of twins conceived spontaneously.

STUDY DESIGN

A retrospective cohort study was conducted. Subjects were delivered by a single obstetric practice between 2005 and 2011 at the Mount Sinai Medical Center. Maternal and neonatal data were recorded. Our primary outcome was the incidence of SGA, defined as birth weight <10th percentile, from the three modes of conception. Chi square, ANOVA, Fisher's exact test, the Kruskal-Wallis test, the Mantel-Haenszel test, and logistic regression were used in the analysis.

RESULTS

In unadjusted analysis, using the records of 756 infants from 378 mothers of twin pregnancies, twins conceived by ovulation induction had an increased incidence of SGA (28.1%) compared to those conceived spontaneously (17.1%) and by in vitro fertilization (16.5%, p = 0.006). In a logistic regression model accounting for correlated responses between twins and adjusting for gestational age, gender, chorionicity, and maternal age, the odds ratio (95% confidence interval [CI]) of SGA for the ovulation induction group compared to the spontaneous conception group was 2.64 (1.38-5.05, p = 0.003). The odds ratio (95% CI) of SGA for the in vitro fertilization group compared to the spontaneous conception group was 1.51 (0.88-2.61, p = 0.135).

CONCLUSIONS

When adjusted for gestational age, gender, chorionicity, and maternal age, twin neonates conceived by ovulation induction, but not those conceived by in vitro fertilization, had increased odds of SGA compared to those conceived spontaneously.

Does early enteral feeding prevent hypoglycemia in small for gestational age neonates?

OBJECTIVES

To determine the association between early enteral feeding and the incidence of hypoglycemia in SGA neonates.

STUDY DESIGN

A retrospective review to evaluate the association of hypoglycemia and early enteral feeding was performed. Eligible patients were born full-term between 1/1/2008-7/1/2011 and classified as SGA (birth weight <10th percentile). We collected the first two serum glucose values, time to enteral feeds and feeding type. The primary outcome was incidence of hypoglycemia, defined as serum glucose values ≤35 mg/dL (1.9 mmol/L).

RESULTS

203 infants were included in the analysis. 94 patients were fed between the first and second glucose measurement and 109 were not. Although the incidence of hypoglycemia was greater in the group that received early enteral feeds (13% versus 4%; p = 0.02), feeding was not a significant predictor of the second serum glucose in a multivariable regression model (p = 0.078).

CONCLUSIONS

This study suggests that early enteral feeding does not predict hypoglycemia in this cohort of SGA neonates.

Development of a statewide collaborative to decrease NICU central line-associated bloodstream infections

OBJECTIVE

To characterize hospital-acquired bloodstream infection rates among New York State's 19 regional referral NICUs (at regional perinatal centers; RPCs) and develop strategies to promote best practices to reduce central line-associated bloodstream infections (CLABSIs).

STUDY DESIGN

During 2006 and 2007, RPC NICUs reported bloodstream infections, patient-days and central line-days to the Department of Health, and shared their results. Aiming to improve, participants created a central line-care bundle based on visiting a potentially best performing NICU and reviewing the literature.

RESULT

All 19 RPCs participated in this quality initiative, contributing 218,096 patient-days and 56,911 central line-days of observation. Individual RPC nosocomial sepsis infection (NI) rates ranged from 1.0 to 5.8 NIs per 1000 patient-days (2006), and CLABSI rates ranged from 2.6 to 15.1 CLABSIs per 1000 central line-days (2007). A six-fold rate variation among RPC NICUs was observed. Participants unanimously approved a level-1 evidence-based central line-care bundle.

CONCLUSION

Individual RPC rates and consequent morbidity and resource use attributable to these infections were substantial and varied greatly. No center was without infections. It is hoped that the cooperation and accountability exhibited by the RPCs will result in a major network for characterizing performance and improving outcomes.

Death as a complication of peripherally inserted central catheters in neonates

We report 2 neonatal deaths caused by cardiac tamponade related to peripherally inserted central catheters (PICCs). A total of 3 deaths were noted for 390 PICCs placed, giving an incidence of 0.76%. To determine the magnitude of neonatal death related to PICCs, directors of neonatal intensive care units in the United States were surveyed by means of a questionnaire. Myocardial perforation and pericardial effusion were reported by 29% and 43%, respectively. Deaths were attributed to PICCs by 24% of the respondents. Uniform guidelines need to be formulated to avoid this complication.

Neonatal care of infants with head and neck anomalies

This article reviews the most common serious head and neck congenital anomalies and traumatic injuries that present at or around the time of birth from the perspective of neonatal caregivers. The focus is on the steps necessary to manage these infants in the delivery room and during the first days of life. An organized multidisciplinary team approach is critical to success.

The Bell Commission: ethical implications for the training of physicians

In 1989, the New York State Legislature enacted New York State Code 405 in response to the death of a patient in a New York City hospital. Code 405 was the culmination of a report (the Bell Commission Report) that implicated the training of residents as part of the problem leading to that tragic death. This paper explores the consequences of the regulatory changes in physician training. The sleep deprivation of house officers was considered a major issue requiring correction. There is little evidence to support the claim that sleep deprivation is a serious cause of medical misadventures. Nevertheless, the changes in house officers' working hours and responsibilities have profound implications. Changes in the time allotted to teaching, the ability to learn from patients admitted after a shift is over, and the increasing loss of continuity, all may have a negative impact on physician training. It is not clear that trainees are being realistically prepared for the actual practice of medicine - physicians often work extended hours. The most serious concern that has been raised is the loss of professionalism by physicians. Residents are now viewing themselves as hourly workers, and the State has intervened in an area of training formerly left to the profession to manage. We are now training doctors in New York State who will be comfortable working in an hourly wage setting, but not in the traditional practice of medicine as it has been in the United States during this century. We are concerned that this may sever the bond between doctor and patient - a bond that has been the bedrock of our conception of a physician.

The horns of the dilemma are sharp

I would like to present the details of an actual case from my own experience over which I, along with the family, have agonized. I think this case brings into focus some of the unique issues in perinatal medicine where multiple patients, some real and some potential, can enter into a single decision. I hope that through this presentation others may gain insight into the complexities of applied ethics in perinatal medicine.

Stop experimenting on my baby!

Having a small sick baby in a neonatal intensive care unit can be an extremely difficult experience for any family. A minority family brings to this setting the additional burden of a concern that racism may affect the care their child receives. While the technology may be overwhelming, the unique rules and an apparent disparity in the enforcement of these rules can suggest discrimination. In some cases, these parental perceptions lead to a charge of experimentation. An increased understanding by health care providers of the cultural differences and life experiences that families bring to stressful situations can improve communication.

Expression of intestinal trefoil factor in developing rat intestine

Intestinal trefoil factor (ITF or TFF3), a small peptide secreted at the mucosal surface by goblet cells throughout the mature intestine, appears to play important roles in the maintenance and repair of the intestinal mucosal barrier. To study the expression of TFF3 during development, intestinal tissues were collected from rats at different development stages and examined by Northern blot analysis, Western blot analysis and immunohistochemical staining for TFF3 mRNA and protein expression. The results demonstrate that rat TFF3 mRNA is not detected until the 17th gestational day (term = 22 days), the expression is greater on gestational day 20 and increased further postnatally. TFF3 protein is first detected by Western blotting and immunohistochemical staining on gestational day 20. Further increases in TFF3 protein expression are demonstrated at around the weaning period. In conclusion, significant expression of rat TFF3 commences late in gestation and its expression is relatively deficient in immature rats. Expression of TFF3 may be deficient in premature infants and, therefore, may have a role in the development of necrotizing enterocolitis.

Pulse oximetry saturations in the first 6 hours of life in normal term infants

The pulse oximetry saturation values and the average percentage of time that normal newborns spend at different saturation ranges in the first 6 hours of life were determined in a cross-sectional study. Pulse oximetry saturation values were measured for a single 20-minute period in 101 normal term newborns between 20 minutes and 6 hours of age. The 25th percentile saturation values in the first postnatal hour (range 91%-100%) were lower than those from the second postnatal hour (range 96%-100%) onward. There was no significant difference between the 50th percentile (range 96%-100%) and the 75th percentile (range 97%-100%) saturation values in all postnatal hours. The babies spent a majority of time with saturations > or = 96% in all postnatal hours. A newborn more than 20 minutes old who does not achieve a pulse oximetry saturation value of 96% over several minutes of observation may need evaluation or continuous monitoring.

Increased survival in low birth weight neonates given prophylactic surfactant

OBJECTIVE

To compare the effectiveness of a prophylactic surfactant treatment strategy (PRO) to the effectiveness of a rescue (RESC) surfactant treatment strategy in patients at high risk for developing hyaline membrane disease (HMD).

STUDY DESIGN

We analyzed data from a retrospective cohort consisting of all patients admitted to the neonatal intensive care units at the centers participating in the recently completed Infasurf-Survanta Comparative Trial. To be in the cohort, a patient had to be admitted during the trial, be <48 hours of age on admission, have a gestational age of <30 weeks, have a birth weight of 501 to 1250 gm, and be free of congenital anomalies. Twelve centers participated in this study. They contributed 1097 patients of whom 381 were treated with a PRO strategy.

RESULTS

Survival was significantly higher in the PRO-strategy patients (84% vs 72%, p < 0.05) as was survival without oxygen requirement at a postconceptional age of 36 weeks (60% vs 46%, p < 0.05). In addition, the patients with PRO had a lower prevalence of grade III and IV intraventricular hemorrhage (IVH, 9% vs 14%, p < 0.05). All analyses were controlled for birth weight and type of study center.

CONCLUSION

These data support the conclusion that using a PRO treatment strategy results in improved survival in patients at risk for developing HMD. A PRO treatment strategy may also decrease the likelihood of developing a severe IVH.

Gestational age-dependent extravillous cytotrophoblast osteopontin immunolocalization differentiates between normal and preeclamptic pregnancies

PROBLEM

Normal placentation requires modulation of proliferative cytotrophoblast to an invasive phenotype. Preeclampsia is characterized by failed cytotrophoblast invasion and arterial remodeling. Osteopontin (OPN) is an extracellular matrix protein implicated in cell adhesion, spreading, and invasion.

METHOD OF STUDY

To investigate gestational age-related OPN expression, placental immunostaining was performed. To investigate the role of OPN in uteroplacental vascular pathology, placental immunostaining from pregnancies with preeclampsia (n = 12), fetal growth retardation (FGR) (n = 8), or both (n = 4) was compared with gestational age-matched controls (n = 24).

RESULTS

In non-preeclamptic pregnancies, OPN immunolocalized to basal plate and intervillous cytotrophoblasts from 24-30 weeks (n = 13). In preeclampsia, OPN immunoreactivity was detected from 24-40 weeks. Cytotrophoblasts from FGR placentas were OPN-positive until 30 weeks, unless preeclampsia accompanied the FGR. In this case, cytotrophoblasts were OPN-positive from 24-40 weeks.

CONCLUSIONS

The data suggest a role for OPN in cytotrophoblast invasion of the maternal vasculature/extracellular matrix during non-preeclamptic placentation, and OPN may serve as a marker for placental bed remodeling.

Noninvasive estimation of serum bilirubin

OBJECTIVE

The aim of this study was to evaluate the accuracy and clinical usefulness of a new computer-driven, hand-held device (Chromatics Colormate III) to estimate serum bilirubin from skin-reflectance (skin color) of neonates.

STUDY DESIGN

A total of 2441 infants (both term and premature) at two hospitals had repeated measurements of transcutaneous bilirubin. Of these infants, 900 had one or more laboratory determinations of serum bilirubin. Many of the infants had early measurements of skin color before the onset of jaundice. A visual estimate of the degree of jaundice was made by a health care worker when the laboratory study was drawn. A subgroup of 61 infants was also studied while undergoing phototherapy with a total of 284 comparisons obtained. The reproducibility of the instrument was assessed separately using standardized color tiles and repeated measurements by multiple operators.

RESULTS

The range of serum bilirubin measurements that had concurrent skin color measurements was 3.22 to 338.1 micromol/L (0.2 to 21 mg/dL). The linear regression indicated an r = 0.956, and 95% of the skin color measurements were within 32.2 micromol/L (2.0 mg/dL). There was no interference with the accuracy of the device because of infant race or weight, or because of the use of phototherapy. The device provided reproducible information when infants were tested repeatedly over 30 minutes; the coefficient of variation for the transcutaneous bilirubin measurement was 3.1% around a mean estimate of 135.32 micromol/L (8.4 mg/dL).

CONCLUSION

The Chromatics Colormate III allows for a clinically useful estimate of serum bilirubin in a wide variety of infants. By using a color discrimination algorithm and obtaining a skin measurement before the onset of icterus, this instrument can provide valuable clinical information that obviates the need for serum bilirubin determinations. Its use in newborn nurseries may allow physicians to shorten length of stay more safely and decrease the use of invasive blood tests.

Comparison of Infasurf (calf lung surfactant extract) to Survanta (Beractant) in the treatment and prevention of respiratory distress syndrome

OBJECTIVE

To compare the relative safety and efficacy of Infasurf (calf lung surfactant extract; ONY, Inc, Amherst, NY, IND #27169) versus Survanta (Beractant, Ross Laboratories, Columbus, OH) in reducing the acute severity of respiratory distress syndrome (RDS) when given at birth and to infants with established RDS.

DESIGN

A prospective, randomized, double-blind, multicenter clinical trial.

SETTING

Thirteen neonatal intensive care units participated in the treatment arm: seven of these concurrently participated in the prevention arm.

PATIENTS

The treatment arm enrolled infants of </=2000 g birth weight with established RDS, and the prevention arm enrolled infants of </=29 weeks' gestation with birth weights <1250 g.

INTERVENTION

Infants were randomly assigned to receive Infasurf (n = 303, treatment arm; n = 180, prevention arm) or Survanta (n = 305, treatment arm; n = 194, prevention arm) in accordance with the Survanta package insert instructions.

OUTCOME MEASURES

We projected a 25% reduction between groups in the need for a third dose of surfactant for infants with established RDS, and a 25% reduction in the need for a second dose of surfactant for infants who received prophylactic surfactant. Secondary outcomes included the severity of RDS measured by inspired oxygen concentrations and mean airway pressure, air leaks, complications associated with surfactant administration, and survival to 36 weeks' postmenstrual age without the need for oxygen supplementation.

RESULTS

In the treatment arm, there was no difference between groups in the number of infants requiring more than two doses of surfactant. The interval between doses was significantly longer for Infasurf, suggesting an increased duration of treatment effect. The inspired oxygen concentration and mean airway pressure were lower in the Infasurf infants during the first 48 hours in the treatment arm. In the prevention arm, there were no differences with respect to the number of surfactant doses. The dosing intervals were longer for Infasurf infants after the second dose. No difference in inspired oxygen or mean airway pressure was noted during the first 72 hours. There were no significant differences in the incidence of air leaks, complications associated with dosing, complications of prematurity, mortality, or survival without chronic lung disease in the prevention or treatment arm.

CONCLUSIONS

Infants treated with Infasurf have a modest benefit in the acute phase of RDS. Infasurf seems to produce a longer duration of effect than Survanta.

Neonatal jaundice: when to treat, when to watch and wait

What clinical circumstances call for aggressive treatment of jaundice in newborns? Is cessation of breast-feeding necessary to help bring down the high bilirubin concentration? When should phototherapy be started--and stopped? The authors address these and other questions in this thorough guide to differential diagnosis and management of neonatal jaundice.

Infant care knowledge of primiparous urban mothers

Because hospitals are discharging postpartum women within 48 hours of delivery, little time is available for maternal baby care instruction. Therefore it is important that any teaching, whether in the hospital or in an outpatient setting, concentrate on topics that provide the greatest benefit to the mother and child. This study provides an initial view of maternal knowledge of well baby care in an attempt to discern topics of common misinformation and misunderstanding. Fifty primiparous, English-speaking mothers were interviewed. The interview consisted of questions dealing with social support for the mother; employment or schooling; source of prior child care knowledge; and knowledge of feeding, diapering, sleeping, calming, bathing, and sickness of newborn infants. The data gathered indicate that although most women report one or more sources of knowledge, several gaps exist in their preparedness. The traditional information presented may overemphasize known areas at the expense of some that have significant consequences for health and safety. Many hospitals offer postpartum classes in bathing. These data indicate that if these programs could be expanded to include more practical information, they would provide a beneficial learning experience at a critical time in a new mother's life.

Metabolic correlates of neurologic and behavioral injury after prolonged hypothermic circulatory arrest

Thirty-two inbred weanling puppies were divided into four groups to study the effect on cerebral blood flow and metabolism of different hypothermic strategies for cerebral protection similar to those used during cardiac operations in infancy. All animals were cooled to 18 degrees C. The animals in the hypothermic control group were immediately rewarmed. One group underwent 30 minutes of hypothermic circulatory arrest at 18 degrees C; another group had 90 minutes of hypothermic circulatory arrest at 18 degrees C, and the final group had low-flow cardiopulmonary bypass (25 ml/kg per minute) at 18 degrees C for 90 minutes. All animals had preoperative and postoperative neurologic and behavioral evaluation and extensive intraoperative monitoring of cerebral blood flow, cerebral vascular resistance, and oxygen and glucose uptake and metabolism: quantitative electroencephalography was also monitored before, during and after operation, but those results are reported separately. Two animals in the 90-minute arrest group died, and all the survivors showed evidence of clinical, neurologic, and behavioral impairment on postoperative day 1, with residual abnormalities in all but one animal on day 6. In contrast, the survivors in all the other groups showed no significant clinical or behavioral sequelae. Cerebral metabolism was reduced only to 32% to 40% of baseline values at 18 degrees C in all groups, although systemic metabolism was only 16% of normal. Cerebral metabolism returned promptly to baseline in all groups during rewarming and remained at baseline levels throughout the 8 hours of follow-up. Cerebral blood flow showed marked hyperemia in the hypothermic arrest groups during rewarming but then significant reductions below baseline values in all groups except the controls at 2 and 4 hours after the operation, lasting as late as 8 hours after the operation in the 90-minute arrest group. Cerebral vascular resistance showed increases in all groups at 2 and 4 hours after the operation, which persisted in the 90-minute arrest group at 8 hours. Cerebral metabolism was maintained at baseline levels despite postoperative decreases in cerebral blood flow and increases in cerebral vascular resistance by increases in oxygen and glucose extraction. The result was very low sagittal sinus oxygen saturations in all groups, most marked in the 90-minute arrest groups, which had a saturation of only 24% 8 hours after the operation. Our data show a severe, prolonged disturbance in cerebral blood flow and cerebral vascular resistance after 90 minutes of hypothermic circulatory arrest at 18 degrees C, which correlates with clinical evidence of cerebral injury.(ABSTRACT TRUNCATED AT 400 WORDS)

Maternal and neonatal risk factors for cryptorchidism

We assessed risk factors for cryptorchidism in a prospective hospital-based cohort study at Mount Sinai Hospital in New York City. We examined at birth 6,699 singleton male neonates who were delivered between October 1987 and October 1990. Follow-up examinations were undertaken at 3 months and 1 year for those diagnosed as cryptorchid at birth. We calculated prevalence ratios and adjusted odds ratios according to selected maternal and neonatal characteristics for those who remained cryptorchid at the 1-year assessment. We found elevated risks for maternal obesity [prevalence ratio = 2.42; 95% confidence interval (CI) = 1.11-5.27], for infants delivered by cesarean section (adjusted odds ratio = 2.17; 95% CI = 1.29-3.65), for low birthweight (adjusted odds ratio = 2.29; 95% CI = 1.12-4.70), for preterm birth (adjusted odds ratio = 2.25; 95% CI = 1.16-4.35), and for infants with congenital malformations (prevalence ratio = 13.97; 95% CI = 1.27-26.67). We observed a seasonal effect, with a peak in births of cryptorchid infants during September through November and a smaller peak during the months of March through May. We found no evidence that young women, white women, or primiparas were at increased risk.

New perspectives on neonatal hyperbilirubinemia

Notwithstanding a number of advances in the understanding of hyperbilirubinemia and its treatment in the newborn, controversy continues. The trend has been to decrease interventions and observe and manage infants with jaundice as outpatients. This trend will probably prove to be both medically and economically sound. In the absence of significant hemolysis or other underlying medical conditions such as infection, many physicians are now comfortable with expectant observation for those healthy full-term infants with serum bilirubin measurements of less than 18 mg/dL. New thinking about this condition and advances in treatment may transform hyperbilirubinemia in neonates into a medical curiosity.

Prevalence and natural history of cryptorchidism

OBJECTIVE

A prospective hospital-based cohort study was conducted to determine the prevalence rates of cryptorchidism at birth, 3 months, and 1 year of age.

DESIGN

A total of 6935 consecutive male neonates delivered at Mount Sinai Hospital in New York City between October 1987 and October 1990 were examined at birth for cryptorchidism. Standardized examination and classification criteria were used. Infants classified as cryptorchid at birth were reexamined at 3 months and 1 year after the expected date of delivery.

RESULTS

Of 6935 neonates assessed at birth, 255 (3.7%) were found to be cryptorchid at birth. The rates were significantly elevated for low birth weight, preterm, small-for-gestational age, and twin neonates. The overall rate had declined to 1.0% by the 3-month assessment and 1.1% at the 1-year assessment. Although the rates at the 1-year assessment tended to be higher for low birth weight and preterm infants, no significant group differences were observed.

CONCLUSIONS

Since the prevalence rates in this study are similar to those reported several decades ago, these data provide no evidence that the rate of cryptorchidism has increased either at birth or by 1 year of age. Furthermore, most testes that descend spontaneously do so within the first 3 months after the expected date of delivery.

Cerebral blood flow and metabolism in hypothermic circulatory arrest

Although hypothermic circulatory arrest has been accepted for use in cardiovascular operations, the potential for cerebral injury exists. The mechanism of the cerebral injury remains unclear. To address these questions we studied cerebral blood flow and metabolism. Sixteen puppies were randomly assigned to undergo either 45 or 90 minutes of hypothermic circulatory arrest after perfusion/surface cooling to 13 degrees C. Cerebral blood flow, cerebral oxygen and glucose metabolism, and cerebral vascular resistance measurements were obtained at 37 degrees C, 13 degrees C, 10 minutes after reperfusion, 30 degrees C and 2 and 4 hours after hypothermic circulatory arrest. No neurologic or behavioral changes were observed in any of the long-term survivors (11/16). Metabolic and cerebral blood flow data did not differ between groups. Cerebral blood flow was significantly lower in the late postarrest measurements, whereas oxygen and glucose consumption had returned to baseline values. In the presence of low cerebral blood flow and high cerebral vascular resistance it is notable that control levels of oxygen consumption were attained by abnormally high oxygen extraction. These data strongly suggest a vulnerable interval after hypothermic circulatory arrest in which cerebral metabolism is limited by cerebral blood flow.

Diffuse hepatic infarction with complete recovery in a neonate

An infant born by cesarean section because of placenta previa had hypovolemia with disseminated intravascular coagulopathy. Diffuse hepatic infarction developed, but the infant ultimately recovered completely.

The neonatal transitional circulation: a combined noninvasive assessment

Dramatic changes occur in the circulation of the newborn during the transition from fetal to neonatal life. Closure of the foramen ovale and ductus arteriosus, decrease in pulmonary vascular resistance, and improvement in right ventricular compliance are among these changes. These physiological-anatomical events were characterized by means of two-dimensional, Doppler and color flow echocardiography. Forty-five full-term infants (22 male, 23 female) were studied at a mean age of 4.2 hours (T1), 25.5 hours (T2), 49.8 hours (T3), and 73.8 hours (T4) by two-dimensional, Doppler and color flow echocardiography. At T1, T2, T3, and T4, the ductus arteriosus was patent by color flow echocardiography in 100%, 34%, 22%, and 11%, respectively. Conversely, patency of the ductus by Doppler alone was detected in 100% (T1), 13% (T2, T3), and 11% (T4). Reversal of flow in the descending aorta, reflective of diastolic ductal filling, was not sensitive in detecting ductal patency (T1 50%, T2 3%, T3 and T4 0%). The patency of the foramen ovale was noted to decrease over the course of the study. Right ventricular compliance was quantitatively assessed by pulsed-Doppler diastolic properties (E-to-A ratio). This changed significantly from T1 to T4 (0.90 to 0.97) reflecting improving compliance of the right ventricle. The ratio of acceleration to ejection time, a Doppler estimation measure of pulmonary vascular resistance, increased from 0.28 to 0.33 (T1 to T4) reflecting a decrease in pulmonary vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Evolving issues in surrogate motherhood

Surrogate mothering is an arrangement whereby a woman who gives birth to an infant intends--through a contractual agreement--to give that baby to another couple. The recent Baby M case in the United States has raised numerous legal concerns causing many legislative bodies to consider possible statutes to regulate or prohibit surrogacy. The competing interests among and between the individuals involved in this relationship (i.e., the surrogate mother, the couple, the baby, and society) suggest various ethical issues related to benefits, risks, and autonomy. Legal and ethical concerns surrounding the technologically possible procedure of surrogate motherhood are discussed.

The effect of aminophylline on gastrointestinal blood flow and oxygen metabolism in the conscious newborn lamb

Aminophylline, widely used in the neonatal period, has been reported to be associated with necrotizing enterocolitis. We hypothesized that aminophylline might alter gastrointestinal blood flow and oxygen delivery. The effects of this drug on gastrointestinal (GI) blood flow and oxygen delivery, consumption, and extraction were examined using the radioactive microsphere method in ten chronically catheterized, unanesthetized lambs aged 5-12 days. While cardiac output and systemic oxygen consumption did not change, we found statistically significant increases (p less than 0.05) in small intestinal blood flow as a function of lamb weight and as a percentage of cardiac output. Splanchnic oxygen consumption also increased significantly. The oxygen reserve available to the GI tract can be compromised by aminophylline at levels similar to those used in the human neonate for treatment of apnea.

Hyperosmolal feedings and gastrointestinal blood flow and oxygenation in newborn lambs

Hyperosmolal feedings have been implicated as a cause of potential disruption to the physiology of the neonatal intestinal tract. To evaluate this we studied eight awake lambs (11 +/- 2 days old) with chronically implanted catheters in the portal sinus, descending aorta, and left and right ventricles. Blood flow (Q) was calculated with the radionuclide-labeled microsphere technique and O2 delivery (DO2) and consumption (VO2) by the Fick principle using blood O2 contents. Lambs were studied initially after a 4-h fast and sequentially at 2, 3, and 4 h after eating a hyperosmolal (590 mOsmol) formula. Cardiac output (mean +/- SEM, 332 +/- 22 ml.min-1.kg-1) and whole animal VO2 (16.5 +/- 2.5 ml O2.min-1.kg-1) remained stable. Total gastrointestinal (GI) blood flow increased 28% by 3 h. Small intestine Q increased 21% 3 h after feeding and then returned to baseline. Similarly, large intestinal Q increased 77% after feeding and remained elevated. There was no effect on stomach Q. Total GI vascular resistance fell 28% 3 h after feeding then returned to baseline. DO2 to the GI tract increased at 3 h and returned to baseline. There was no change, though, in GI VO2 (3.9 +/- 0.4 ml O2.min-1.100 g-1) or in the extraction (VO2/DO2) of oxygen (21.2 +/- 1.8%) during the study. Furthermore, there was no evidence for GI tract acidosis at any time. Systemic organ blood flow (except hepatic arterial blood flow) remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood flow and oxygen delivery to the organs of the neonatal lamb as a function of hematocrit

We chronically catheterized 15 newborn lambs (9.5 +/- 2.8 days) and measured the distribution of cardiac output by the radionuclide-microsphere technique at hematocrits ranging from 10 volumes % to 55 volumes %. Seven animals were made progressively anemic and eight polycythemic by means of exchange transfusions. Cardiac output and heart rate increased with decreasing hematocrit while whole body oxygen consumption showed a small decrease during severe anemia. Both cerebral and cardiac blood flow markedly increased during anemia which assured a relatively stable oxygen delivery to both organs. The changes seen for blood flow to the carcass (skin, bones, and muscle) were predictable from the effects of blood viscosity: small decreases in flow at the highest hematocrits and small increases in flow at the lowest hematocrits. Consequently, oxygen delivery was as low as 1 ml of oxygen/min/100 g at a hematocrit of 10 volumes %. Renal blood flow remained unchanged while oxygen delivery fell when hematocrit was decreased. Hepatic oxygenation was measured using a modification of the Fick principle. Hepatic blood flow showed only a small decrease as hematocrit increased and changed minimally during anemia resulting in a falling delivery of oxygen with anemia. A stable hepatic oxygen consumption was assured by a marked increase in oxygen extraction during anemia. Two differing organ responses to changes in hematocrit can be seen in the newborn: the brain and heart vary blood flow to assure an adequate delivery of oxygen while a number of other organs show less blood flow regulation and, most likely, vary oxygen removal from blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of varying hematocrit on intestinal oxygen uptake in neonatal lambs

We chronically catheterized 15 newborn lambs (9.5 +/- 2.8 days) and measured intestinal blood flow (Qi) by the radionuclide microsphere technique at hematocrit levels ranging from 10 to 55%. Seven animals were made progressively anemic and eight polycythemic by means of exchange transfusions. Using the Fick principle, we calculated intestinal oxygen delivery (Di o2), oxygen consumption (Vi o2), and oxygen extraction. Initial base-line values were Qi = 195.5 ml . min-1 . 100 g intestine-1, Di o2 = 22.1 ml . min-1 . 100 g-1, Vi o2 = 4.8 ml . min-1 . 100 g-1, and O2 extraction = 22.5%. As the hematocrit was lowered, Di o2 decreased and O2 extraction increased and vice versa when the hematocrit was raised. Vi o2 remained constant, but Qi did not correlate with changes in hematocrit. However, intestinal blood flow, as a percent distribution of total blood flow, decreased with lower hematocrit levels. At no time was there any evidence of anaerobic metabolism as measured by excess lactate production. Our data indicate that the intestines of neonatal lambs are capable of maintaining their metabolic needs over a wide range of oxygen availability induced by a changing hematocrit. The primary mechanism is through alteration of oxygen extraction. Within the range of our experiments, no critically low oxygen availability was attained at which anaerobic metabolism became significant.

A method to maintain infant temperature

A new insulating material (Thinsulate) was used to provide thermal protection for newborn infants. Infant core temperature was measured as part of a randomized study comparing the efficacy of an insulated bunting, an insulated hat, and routine management. The new bunting was superior in terms of its ability to maintain the infant's core temperature on arrival in the regular nursery. Nursing staff and parental acceptance was high, and further consideration should be given to defining the role of this new insulating material in the care of the newborn.

The effects of sodium nitroprusside on blood flow and oxygen delivery to the organs of the hypoxemic newborn lamb

Vasodilators are used in newborns under conditions where hypoxia may be prominent. To study the effects of vasodilator therapy on organ oxygen delivery we measured blood flow (using radioactive microspheres) and arterial oxygen content in six chronically catheterized newborn lambs. Cardiac output and its distribution were measured during normoxia, hypoxia (10% O2 and 5% CO2), and hypoxia with a nitroprusside infusion. Hypoxia decreased oxygen content but did not change heart rate, mean blood pressure, or cardiac output. When nitroprusside was infused during hypoxemia, oxygen content and heart rate were not affected, but mean arterial blood pressure fell (39% decrease). During hypoxemia, blood flow increased to the heart, brain, and carcass but decreased to the gastrointestinal tract. When nitroprusside was infused during hypoxemia, blood flow decreased to the heart, brain, kidneys, and carcass. Oxygen delivery (arterial O2 content X blood flow) decreased to the brain as well as to kidneys, stomach, and carcass when nitroprusside was given to the hypoxemic lamb.

Hepatic oxygenation during arterial hypoxemia in neonatal lambs

We identified the effects of reductions in arterial blood oxygen concentration from 15.0 to 4.0 ml O2/dl blood on hepatic blood flow, oxygen delivery, oxygen consumption and oxygen extraction in nine chronically catheterized lambs, 9 +/- 1 (SD) days of age. Hypoxemia was induced by administering a gas mixture low in oxygen to the unanesthetized lambs. Hepatic blood flow was measured with the radioactive microsphere technique; hepatic oxygen delivery, extraction, and consumption were calculated with modifications of the Fick principle. When the lambs breathed room air, hepatic blood flow was 235 +/- 30 ml/min/100 gm (mean +/- SD); hepatic oxygen delivery, 24.6 +/- 3.0 ml O2/min/100 gm; oxygen extraction, 37 +/- 11%; and hepatic oxygen consumption, 8.9 +/- 1.9 ml O2/min/100 gm. As arterial blood oxygen concentration was reduced from 15 to 6.5 ml O2/dl blood, hepatic blood flow did not change. When the concentration was less than 6.5 ml O2/dl, hepatic blood flow decreased as a result of a decrease in portal blood flow. Hepatic oxygen delivery decreased in the whole range of arterial blood oxygen concentrations studied. Despite reductions in oxygen delivery of up to 50%, hepatic oxygen consumption did not fall because hepatic oxygen extraction increased as compensation. Oxygen consumption, however, was stable only when hepatic blood flow did not change in response to hypoxemia. When hepatic blood flow fell, hepatic oxygen consumption also fell. Our data indicate that hepatic oxygen requirements can be met during hypoxemia by increases in hepatic oxygen extraction as long as hepatic blood flow does not change. When hepatic blood flow falls, hepatic oxygen consumption decreases even though oxygen reserves are still present. These data indicate that hepatic oxygenation in the neonate, as in the adult, is dependent on stable hepatic perfusion rather than adequate oxygen supply.

Blood flow and oxygen delivery to fetal organs as functions of fetal hematocrit

The purpose of our experiments was to relate blood flow and oxygen delivery (blood flow x arterial blood oxygen concentration) to fetal organs as functions of fetal hematocrit. In 12 chronically catheterized fetal lambs, we observed two patterns of responses of fetal organs and tissues to isovolemic alterations in fetal hematocrit from 12% to 55%. In group 1 organs (brain, heart, adrenal glands), blood flows increased as hematocrit was either raised or lowered from normal such that oxygen delivery to these organs was stable over the entire range of hematocrits studied. In group 2 organs (gastrointestinal tract organs, spleen, kidneys, placenta, and carcass), blood flows varied little over the range of hematocrits from 12% to 40% or 45% but decreased at hematocrits greater than or equal to 40% to 45%. Because of these flow responses, oxygen delivery to these organs and tissues was maximal at hematocrits ranging from 32% to 38%. Our data indicate that the various organs of the unanesthetized fetal lamb respond in different ways to alterations in hematocrit. It is of particular interest that, in the great majority of the organs of the fetus, oxygen delivery is maximal at hematocrits considered normal for the fetal lamb in utero.

Neonatal intestinal oxygen consumption during arterial hypoxemia

In 12 chronically catheterized neonatal lambs, we determined intestinal tract blood flow (Qi) and O2 consumption (VO2i) at O2 contents of arterial blood (CaO2) ranging from 15.3 to 3.2 ml O2/dl blood. We measured Qi with the radioactive microsphere technique and computed intestinal O2 delivery (DO2i), VO2i, and O2 extraction (VO2i/DO2i) using the Fick principle. In lambs breathing air, mean Qi = 214 ml X min-1 X 100 g intestine-1, DO2i = 27.0 ml O2 X min-1 X 100 g-1, O2 extraction = 21%, and VO2i = 5.6 ml O2 Xmin-1 X 100 g-1. During reductions in CaO2, Qi and DO2i decreased. Intestinal O2 extraction increased sufficiently, however, so that VO2i was maintained over the range of CaO2 from 15.3 to about 6.5 ml O2/dl blood. VO2i was independent of Qi at Qi greater than 160 ml X min-1 X 100 g-1. When CaO2 was reduced below values of 6.5 ml O2/dl blood, corresponding to Qi less than 160 ml X min-1 X 100 g-1, VO2i fell in association with increases in the H+ concentration difference between mesenteric venous and arterial blood. These data indicate that the intestinal tract of the neonatal lamb can meet its oxygen requirements when O2 supply varies over a wide range. When O2 availability reaches a critically low level, intestinal anaerobic metabolism develops as the O2 supply to the neonatal intestinal tract becomes inadequate for the O2 demand.

Responses of lymphocytes from human colostrum or milk to influenza antigens

Paired samples of peripheral blood and colostrum or milk were obtained from women 1 to 6 days after delivery. After Ficoll-Hypaque centrifugation, peripheral blood lymphocytes (PBL) and colostrum or milk lymphocytes (COL) were examined for surface membrane characteristics and in vitro proliferative reactivity. As determined by sheep red blood cell rosetting and by immunoglobulin-coated beads, PBL showed an average of 54% T and 12% B lymphocytes, whereas COL showed 33% T and 22% B rosettes, respectively. Paired samples of PBL and COL were used for lymphocyte transformation with three distinct strains of influenza virus: A/USSR, A/Victoria, and B/Hong Kong. Of COL from nine subjects tested against all three strains of influenza virus, five samples (56%) gave positive responses to at least one. These studies indicate that COL contain cells responsive in vitro to several influenza antigens. Such sensitized cells may provide a mechanism for the transfer of antigen responsiveness and protection from the mother to the neonate.

Fetal intestinal oxygen consumption at various levels of oxygenation

In seven chronically catheterized fetal lambs, blood flow and oxygen consumption (VO2) in the combined small and large intestines were determined at various oxygen concentrations in fetal arterial blood (CaO2). Intestinal blood flow (Qi) was measured with the radioactive-microsphere technique; intestinal oxygen delivery (DO2 = Qi X CaO2), VO2 [Qi X C(a-v)O2, where oxygen extraction [C(a-v)O2/CaO2] were computed with the Fick equation. Compared with normally oxygenated fetuses (CaO2 greater than 6.6 ml/dl), moderately hypoxemic fetuses (CaO2 = 4.4-6.6 ml/dl) had decreased intestinal DO2, increased oxygen extraction, and no change in intestinal VO2, Qi, or mesenteric-venous pH and base excess. During severe fetal hypoxemia (CaO2 less than 4.4 ml/dl), DO2 decreased further while oxygen extraction increased substantially. Intestinal VO2 dropped, however, because the rise in oxygen extraction could no longer completely compensate for the reduced DO2. With severe hypoxemia, Qi and mesenteric-venous pH and base excess also fell. These data indicate that the fetal intestinal tract is able to meet its oxygen needs during hypoxemia until a critically low level of oxygenation is reached. Below this level intestinal oxygenation becomes inadequate, and anaerobic metabolism ensures.

Results of feeding a special formula to very low birth weight infants

Fifty-eight premature infants weighing less than 1,600 g at birth were fed a special formula. The formula contained nutrients in amounts recommended by the Committee ono Nutrition of the American Academy of Pediatrics for very low birth weight (VLBW) infants. The feeding studies were carried out at newborn nurseries in Tampa, Florida (study A, n = 25), Pittsburgh, Pennsylvania (study B, n = 20), and Oaklawn, Illinois (study C, n = 13). Study subjects were comparable in birth weight, gestational age, and in the duration of follow-up in the nurseries. All study subjects grew at rates of weight acquisition equivalent to the comparative fetal counterpart. Routine anthropometric measurements were similar to those of fetal development curves. Mean protein intake ranged from 2.3 to 3.7 g/kg/day and mean caloric intake from 105 to 150 kcal/kg/day. Late metabolic acidosis in association with prematurity was absent in all subjects studied as demonstrated by normal pH values, bicarbonate, and partial pressure of carbon dioxide. Serum sodium and serum chloride levels were normal. Serum calcium ranged from 8.3 to 10.1 mg/dl and serum phosphorus from 6.0 to 7.5 mg/dl. Total serum protein levels ranged from 4.5 to 5.1 g/dl. Blood urea nitrogen diminished progressively from 5.1 to 2 mg/dl in the course of the study. Serum glucose levels in samples taken prior to and 2 h after feeding did not demonstrate any evidence of reactive hypoglycemia.

Gastrointestinal tract O2 uptake and regional blood flows during digestion in conscious newborn lambs

We determined gastrointestinal tract O2 uptake, cardiac output, regional blood flows, and whole-body O2 uptake before and for 1-6 h after feeding in 10 chronically catheterized unanesthetized lambs (9-15 days of age). Total gastrointestinal blood flow (sum of blood flows to the stomach, small intestine, and colon, as calculated with the radioactive microsphere technique) increased 23% at 1 h postprandially. This increased flow at 1 h was due to a large increase in blood flow to the stomach, whereas blood flows to the small intestine and colon did not change significantly. By 2 h, stomach blood flow and thus total gastrointestinal blood flow had returned to fasting values. In contrast, total O2 uptake by the gastrointestinal tract organs (stomach, small intestine, and colon) increased 65% at 1 h, 51% at 2 h, and 28% at 3 h postprandially in association with increases in O2 extraction (O2 uptake/O2 delivery) of 41% at 1 h, 45% at 2 h, and 27% at 3 h. There were no digestion-related changes in whole-body O2 uptake or in cardiac output and its distribution to the brain, heart, kidney, liver (hepatic artery), and carcass. Our data indicate that postprandial increases in O2 demand by gastrointestinal tract organs of the newborn animal are met primarily by enhanced tissue O2 extraction, rather than by metabolic hyperemia, because the postprandial hyperemia observed in the neonate is of short duration and is confined to the stomach.

Intragastric feeding in the neonatal dog. Its effect on intestinal osmolality

Hypertonic formulas have been implicated in the etiology of necrotizing enterocolitis. We measured the osmolality of neonatal canine intestinal contents one hour after intragastric feeding of isotonic breast milk, isotonic formula, or hypertonic formula in 1-day-old and 9-day-old puppies. Regardless of the formula tonicity, all intestinal contents were hypertonic in both segments. Hypertonic formula had been diluted, and isotonic feedings concentrated in the neonatal canine intestine. Gastric contents could be recovered only from hypertonic-fed puppies, which implies delayed gastric emptying to permit formula dilution. We conclude that any form of neonatal feeding can lead to hypertonic intestinal contents. Factors other than tonicity of a formula should be considered in the pathophysiology of necrotizing enterocolitis.

Sequential changes in placental blood gases and pH during the hour following delivery

We studied the effect of a delay in blood sampling on the measurement of placental blood gases, pH and calculated bicarbonate. Blood was sampled serially at 15-minute intervals during the hour following delivery from placentas and attached umbilical cords of unasphyxiated term neonates. Placentas and attached cords were stored at room temperature. When blood was sampled exclusively from the segment of the umbilical vein lying within the umbilical cord, there were no statistically significant changes during the time of study in pH, PCO2 or PoO2. When some or all of the serial samples were taken from vessels on the surface of the placenta, there was a statistically and biologically significant decrease in the pH and increase in the PCO2 values of the blood. Our results indicate that the validity of the measurements of umbilical venous blood gases and pH is not affected by up to an hour's delay in blood sampling.

Glucose polymer tolerance in premature infants

Some formulas designed for premature infants contain glucose polymer (GP) as part of their carbohydrate content. GP tolerance tests and lactose tolerance tests were performed on 11 healthy premature infants at 2 to 3 weeks of age to compare their ability to digest and absorb GP and lactose. Total plasma reducing substances (TPRS), plasma insulin (PI), and plasma glucose were measured 10 minutes before and 30, 60, and 120 minutes after the oral carbohydrate test meal. Lactose and GP stimulated a significant increase in TPRS at 30 and 60 minutes and produced similar glycemic responses. However, GP stimulated PI response whether measured as the area under the PI response curve or as the PI/TPRS ratio. It was concluded that although GP and lactose evoke similar glycemic responses, they differ in their abilities to stimulate insulin secretion. The mechanism controlling this differential insulin response is unknown.

Oxygen consumption by the gastrointestinal tract and liver in conscious newborn lambs

We determined blood flow to and O2 consumption (VO2) by the gastrointestinal tract (GI) and liver and also measured cardiac output and whole-body VO2 in nine chronically catheterized unanesthetized lambs (7-16 days of age). Blood flows were calculated with the radionuclide-labeled microsphere technique, and blood O2 contents were measured with an O2 content analyzer. During the fasting state, GI blood flow was 58 +/- 4 (means +/- SE) ml.min-1.kg body wt-1; GI VO2 was 1.4 +/- 0.1 ml O2.min-1.kg-1. Neonatal GI VO2 was linearly related to both GI blood flow and O2 delivery (DO2). GI O2 extraction [(VO2/DO2).100] averaged 28% and did not vary with blood flow or DO2. Liver blood flow was 73 +/- 4 ml.min-1.kg-1 (271 +/- 23 ml.min-1.100 g liver-1), and liver VO2 was 2.0 +/- 0.1 ml O2.min-1.kg-1 (7.3 +/- 0.5 ml O2.min-1.100 g-1). Hepatic O2 extraction varied from 18 to 81% . VO2 by the neonatal liver did not correlate with liver blood flow or DO2. Hepatic O2 extraction, however, was inversely related to liver DO2. Our data indicate that the gastrointestinal tract and liver of the unanesthetized newborn animal exhibit O2 demands 1.5-3 times those reported in the adult. The neonatal gastrointestinal tract meets its O2 demands with a comparatively large blood flow and O2 delivery, whereas the neonatal liver provides for its O2 requirements by varying its O2 extraction.