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Biomedical subjects

R T Hall

Publications and source records attributed to R T Hall.

At least 19 recordsLinked to original sources
PubMed1999

Indications for surfactant therapy--the aAPO2 coming of age.

Indications for administration of surfactant to infants with established respiratory distress syndrome (RDS; rescue therapy) remains an area of continued investigation. Current recommendations vary from use in infants who are intubated and have an aAPO2 <0.22 to use in infants receiving >/=40% oxygen administered in a hood when the PaO2 is <80 TORR (aAPO2 approximately <0.36). This commentary is written in response to the article by Verder et al, in this issue of Pediatrics, who evaluated early versus late treatment of RDS in 60 preterm infants <30 weeks' gestation receiving nasal continuous positive airway pressure (CPAP). Early-treated infants (aAPO2, 0.22 to 0.35; mean, 0.26) had a lower incidence of mechanical ventilation or death (21%) than did late-treated infants (63%), who did not receive surfactant treatment until the aAPO2 was <0.22 (0.15 to 0.21; mean, 0.16). The authors conclude that although approximately half of infants <30 weeks' gestation with RDS can be treated with nasal CPAP alone, early treatment with surfactant when the aAPO2 is 0.22 to 0.36 reduced significantly the need for mechanical ventilation. Limitations of applicability of the study to widespread use include determination of PO2 values from transcutaneous measurements, which may vary from those obtained from arterial samples and affect significantly aAPO2 ratios. Likewise, use of nasal CPAP significantly affects oxygenation, and interpretation of results cannot be extrapolated to intubated infants or those receiving oxygen delivered under a hood. Nonetheless, the use of the aAPO2 ratio and early administration of surfactant are supported by this study.

Blood Gas Monitoring, Transcutaneous↗
PubMed1998

High-dose phenobarbital therapy in term newborn infants with severe perinatal asphyxia: a randomized, prospective study with three-year follow-up.

OBJECTIVE: To determine whether 40 mg/kg phenobarbital given to term infants with severe asphyxia would result in a lower incidence of seizures in the newborn period and an improved neurologic outcome. METHODS: We conducted a randomized, controlled, prospective study. Entry criteria included (1) an initial arterial pH less than or equal to 7.0 with a base deficit 15 mEq/L or more, (2) Apgar score less than or equal to 3 at 5 minutes of age, or (3) failure to initiate spontaneous respiration by 10 minutes of age. Sample size was calculated to detect a 50% reduction in the incidence of neonatal seizures. RESULTS: No differences were present between treatment and control groups with respect to severity of asphyxia assessed by initial arterial pH, base excess, cerebrospinal fluid lactate dehydrogenase concentration or detection of CSF creatine kinase of its BB isoenzyme. Seizures occurred in 9 of 15 infants in the treatment group and 14 of 16 infants in the control group (p = 0.11). No adverse effects were observed from phenobarbital on heart rate, respiratory rate, blood pressure, or arterial blood gas values. Three-year follow-up revealed normal outcome in 11 of 15 infants in the treatment group and 3 of 16 in the control group (p = 0.003). CONCLUSION: Phenobarbital, when administered in a dose of 40 mg/kg intravenously over 1 hour in term, severely asphyxiated newborn infants appeared to be safe and was associated with a 27% reduction in the incidence of seizures and a significant improvement in neurologic outcome at 3 years of age.

Anticonvulsants↗
PubMed1997

Salt supplementation, growth, and nephrocalcinosis in the furosemide-treated weanling rat.

OBJECTIVE: Furosemide treatment in the human neonate is associated with sodium depletion, growth retardation, hypercalciuria and nephrocalcinosis. Dietary sodium intake is known to directly influence urinary calcium excretion. The objectives of this study were to create a rat model of furosemide-induced nephrocalcinosis and to test the effects of dietary sodium supplementation on growth, electrolyte balance, calciuria, and renal calcifications. METHODS: Initially, 18 weanling Sprague-Dawley rats were randomly divided into three groups. Groups A (control) and B were fed a basal diet. Group C was fed a sodium-enriched diet. Groups B and C received furosemide (40 mg/kg) intraperitoneally daily for 28 days. At the end of the study, serum, urine, and kidney samples were obtained for biochemical and histologic analyses. The three groups were then compared for differences in growth, electrolyte homeostasis, calcium excretion and nephrocalcinosis. Subsequently an additional 15 rats were studied to confirm our findings regarding urinary calcium excretion and kidney calcifications. RESULTS: Treatment with furosemide without sodium supplementation (group B) resulted in decreased weight gain compared with group A (137.5 +/- 12.9 vs 154.0 +/- 10.6 g; p < 0.05), hypokalemia (3.7 +/- 0.1 vs. 4.4 +/- 0.4 mEq/l; p < 0.05), and nephrocalcinosis (187.1 +/- 155 vs. 18.8 +/- 6.9 micrograms Ca/g dry kidney; p < 0.05). Sodium supplementation (group C) normalized weight gain and corrected electrolyte abnormalities without increasing calciuria or nephrocalcinosis. CONCLUSIONS: We conclude that in this animal model, chronic furosemide treatment results in growth failure and development of nephrocalcinosis. Sodium supplementation protects against the deleterious effects of furosemide on weight gain and electrolyte homeostasis with no adverse effect on nephrocalcinosis.

Animals↗
PubMed1997

Visual acuity, erythrocyte fatty acid composition, and growth in term infants fed formulas with long chain polyunsaturated fatty acids for one year. Ross Pediatric Lipid Study.

The CNS and the retina are enriched in long chain polyunsaturated (LCP) fatty acids, specifically docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6), which are present in human milk but not in most infant formulas. In the present study of 134 formula-fed and 63 breast-fed infants, we prospectively evaluated whether providing a source of DHA and AA or DHA alone in formula would increase red blood cell (RBC) phospholipid levels of these fatty acids, enhance visual function, or affect growth during the first year. Healthy term infants < 7 d old were randomized to be fed formulas containing linoleic acid (approximately 10% kcal) and alpha-linolenic acid (approximately 1% kcal) plus (1) no added LCP fatty acids (control formula), (2) DHA (0.12 wt% fatty acids) and AA (0.43 wt%) from egg yolk phospholipid (AA + DHA formula), or (3) DHA (0.2 wt%) from fish oil (DHA formula). A breast-fed group was studied concurrently and permitted formula supplementation after 3 mo. Visual acuity was measured using both the acuity card procedure and a visual evoked potential method at 2, 4, 6, 9, and 12 mo. Infants fed the control formula had 10-40% lower RBC levels of DHA and AA than infants in the breast-fed group. Infants fed the AA + DHA formula had levels of both LCP within approximately 10% of the values for infants in the breast-fed group, and infants fed the DHA formula had 25-55% higher DHA levels and 15-40% lower AA levels. There were no differences in growth or in visual function during this 12-mo feeding study.

Anthropometry↗
PubMed1997

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.

Age Factors↗
PubMed1994

Mixed venous oxygenation in critically ill neonates.

OBJECTIVE: To describe the typical ranges for central venous oxygen saturation and PO2 in a group of critically ill neonates and the relationship of these measurements to measurements of arterial oxygenation and indicators of oxygen supply and demand. DESIGN: Survey. SETTING: Newborn intensive care unit (ICU) in a children's hospital. PATIENTS: Eighteen newborn infants (1 to 3 days old) who required mechanical ventilation for respiratory diseases, but who were hemodynamically stable and in acid-base balance. INTERVENTIONS: Umbilical artery and right atrial catheterization were performed, allowing simultaneous blood gas sampling. MEASUREMENTS AND MAIN RESULTS: Simultaneous umbilical arterial and right atrial blood gas measurements were analyzed (n = 100). Mean mixed venous oxygen saturation was 83.3% and mixed venous oxygen tension 37.8 torr (5.1 kPa). The mixed venous oxygen saturation correlated well with the arterial-venous oxygen content difference (C[a-v]O2) and fractional oxygen extraction, r = -.77 (r2 = .59) and -.85 (r2 = .72), respectively (p < .0005). Poor correlation was found between the mixed venous oxygen saturation and arterial oxygen saturation values. Two cases are presented in which measurements of mixed venous oxygenation led to recognition of apparent tissue hypoxia earlier than did measurements of arterial oxygenation. CONCLUSIONS: We conclude that measurement of central venous oxygenation in ill neonates may reflect more accurately the oxygen supply and demand status of the neonate than measurement of arterial oxygenation alone.

Arteries↗
PubMed1994

Oath-sayers.

Explore the source record for details and available documents.

Ethics, Medical↗
PubMed1993

Early onset Haemophilus influenzae sepsis in the newborn infant.

Neonatal sepsis caused by Haemophilus influenzae is characterized by an early onset syndrome associated with pneumonia, shock and neutropenia. Over a 30-month period 13 infants referred to this hospital had early onset H. influenzae sepsis. Obstetric complications included preterm labor (92%), prolonged rupture of membranes > 12 hours (63%), maternal fever (64%), chorioamnionitis (43%), vaginal discharge (44%) and premature rupture of membranes (15%). All 13 infants were symptomatic at delivery and 7 required immediate intubation. Pneumonia and respiratory distress were the prominent clinical findings. H. influenzae was isolated from infant blood, maternal blood, placenta and genital tract. Isolates were predominantly non-type b, beta-lactamase-negative. A study to determine the prevalence of H. influenzae colonization of the genital tract among women attending clinic at the hospital with the most cases showed a rate of 0.3%. Perinatal risk factors and clinical findings in the infants are similar to disease caused by other organisms associated with early onset sepsis.

Blood↗
PubMed1993

Characterization of kinetics and target proteins for binding of human complement component C3 to the surface-exposed outer membrane of Chlamydia trachomatis serovar L2.

In order to characterize the interaction of human complement with Chlamydia trachomatis, flow cytometry was used to quantitate binding of complement component C3 to elementary bodies of C. trachomatis serovar L2 preincubated in fresh serum in the presence or absence of human polyclonal chlamydial antibody. Isolation of each of the complement activation pathways revealed that C3 was activated most effectively by the alternative pathway. The degree of binding by the classical pathway was proportional to the concentration of antibody, but dual-pathway-mediated binding was not greater than antibody-independent alternative pathway binding. Electrophoresis and immunoblotting of detergent-extracted outer membrane protein-C3b complexes indicated that the chlamydial major outer membrane protein was the primary cell surface moiety binding C3b in both the presence and absence of specific antibody. Hydroxylamine cleavage of outer membrane protein-C3b complexes provided evidence that the majority of C3b is bound to the major outer membrane protein by hydroxyl ester bonds. This result was also unchanged by the presence of specific antibody. An unexpected finding was the apparent binding of anti-C3 antibody to a 40-kDa protein of the chlamydial outer membrane complex, perhaps indicating C3 mimicry on the part of the chlamydial major outer membrane protein.

Amino Acid Sequence↗
PubMed1993

Feeding iron-fortified premature formula during initial hospitalization to infants less than 1800 grams birth weight.

OBJECTIVE: A randomized, double-blind study was conducted comparing high-iron content (15 mg/L) with low-iron content (3 mg/L) premature formula given during initial hospitalization to infants with birth weights less than 1800 g to determine the influence of these differing intakes on the iron nutritional status during the first 4 months of life. A third group of similar infants received human milk mixed with an equal volume of liquid fortifier resulting in an iron content of approximately 1.7 mg/L. PATIENTS AND METHODS: Mean birth weight, gestational age, age at study entry, volume of blood removed for studies, and volume of red cells transfused were not different among the three groups. After hospitalization both formula-fed groups were given a cow milk formula with an iron content of 12 mg/L, and breast-fed infants were given an iron-containing multivitamin with a resulting iron intake of 10 mg/d. Infants were observed to 8 weeks after discharge. RESULTS: There were no differences in serum iron, ferritin, transferrin, transferrin saturation, hemoglobin, hematocrit, or reticulocyte count among the three groups at study entry, although mean corpuscular hemoglobin and mean corpuscular volume were lower in infants in the low-iron formula group. Mean plasma ferritin was significantly lower in infants receiving low-iron content premature formula at the time of hospital discharge compared with the other two groups. The incidence of anemia (hemoglobin < 9.0 g/dL) and low transferrin saturation (< 24%) was also greater in the low-iron content formula group. Eight weeks after discharge, the incidence of low plasma ferritin (< 19 ng/mL) remained greater in infants receiving low-iron content formula than in the other two groups. No adverse effects of iron intake were observed. Growth was not different among the three groups. CONCLUSIONS: These data indicate that preterm infants with < 1800 g birth weight receiving premature infant formula benefit from formula given during initial hospitalization containing 15 mg/L iron compared with that containing 3 mg/L.

Anemia, Hypochromic↗
PubMed1992

Intravenous immune globulin for the prevention of nosocomial infection in low-birth-weight neonates. The Multicenter Group for the Study of Immune Globulin in Neonates.

BACKGROUND: Nosocomial infection is a major risk for premature infants with very low birth weights. One reason for their susceptibility to infection may be antibody deficiency, since there is little transfer of maternal IgG to the fetus before 32 weeks' gestation. METHODS: We conducted a multicenter, double-blind study of neonates weighing 500 to 1750 g at birth. A total of 588 neonates were randomly assigned, with stratification for birth weight, to receive periodic intravenous infusions of either immune globulin (500 mg per kilogram of body weight per day) or a placebo. Mortality, morbidity, and nosocomial infection during the next 56 days were assessed. RESULTS: The infusions were well tolerated; mild, reversible adverse reactions occurred in five infants in each group. There was a significant reduction in the risk of a first nosocomial infection in the recipients of immune globulin as compared with the placebo recipients (relative risk, 0.7; 95 percent confidence interval, 0.5 to 0.9). About 85 percent of the nosocomial infections were bacterial; the majority of these were caused by coagulase-negative staphylococci or Staphylococcus aureus. The neonates who received immune globulin had fewer mean days of hospitalization than the controls (62 vs. 68, P = 0.15); among the infants with infections, the difference in the mean length of the hospital stay was even greater (80 days vs. 101 days, P = 0.02). CONCLUSIONS: For premature infants weighing between 500 and 1750 g at birth, treatment with intravenous infusions of immune globulin is safe and reduces the risk of nosocomial infection.

Cross Infection↗
PubMed1992

Early-onset group B streptococcal sepsis: a current assessment.

Group B streptococcus (GBS) is a common cause of early-onset sepsis in neonates. The most recent reviews describing incidence, diagnosis, treatment, and outcome evaluated data on patients from the early 1980s. To obtain current information about this disease, we retrospectively evaluated data on neonates with GBS early-onset sepsis from nine hospitals in the United States between Jan. 1, 1987, and Dec. 31, 1989. There were 245 infants with GBS bacteremia identified among 61,809 live births, resulting in an incidence of 0.32%. Ninety-six infants (39%) were preterm (less than 38 weeks of gestational age). Maternal risk factors for infected preterm and term infants were similar. Antibiotics were administered during parturition in 10% of infants with bacteremia. Mothers of preterm infants received antibiotics up to 48 hours before delivery; mothers of term infants received antibiotics less than 4 hours before delivery. All preterm infants with bacteremia had symptoms; 22% of term infants with bacteremia had no symptoms. Group B streptococcal meningitis was confirmed in 6.3% of infants. Although 86% survived, GBS sepsis increased the birth weight-specific mortality rate up to eightfold in preterm infants and more than 40-fold in term infants. Although the incidence of GBS early-onset sepsis is not changing, we speculate that the improved birth weight-specific survival rate and the changing clinical presentation are due to improved intrapartum and neonatal management.

Bacteremia↗
PubMed1990

A controlled trial of human surfactant replacement therapy for severe respiratory distress syndrome in very low birth weight infants.

In a randomized, controlled study, human surfactant derived from amniotic fluid was administered within 12 hours of birth to infants with severe respiratory distress syndrome who were born at 24 to 32 weeks of gestation weighing less than or equal to 1500 gm. A second dose of surfactant was given to patients in the treatment group if they met ventilator requirements indicating relapse or lack of response to the initial dose. No significant improvement was observed in mortality rate (9/28 vs 15/31) or incidence of bronchopulmonary dysplasia (5/28 vs 3/31) when surfactant-treated infants were compared with control subjects, although there was a significant reduction in initial respirator and inspired oxygen requirements and the arterial/alveolar oxygen ratio improved. In addition, there was a significant reduction in pulmonary air leak in treated infants (10/28 vs 20/31; p less than 0.05). Retreatment was associated with an attenuated ventilatory response and with a higher mortality rate (7/14) than that of infants who did not require a second dose (2/14; p = 0.05), indicating a more severe form of disease. Multiple discriminant analysis, including eight independent variables, revealed that increasing birth weight, earlier age at surfactant treatment, and female gender were significantly associated with survival. These data suggest that early surfactant treatment may reduce mortality rates in very low birth weight infants with severe respiratory distress syndrome, as well as reduce ventilator requirements and the incidence of pulmonary air leaks.

Age Factors↗
PubMed1990

Improved survival and neurodevelopmental outcome for infants less than 801 grams birthweight.

We reviewed the perinatal management and subsequent outcome of infants 401 to 800 gm birthweight delivered in 1983 to 1985 compared with those born in 1980 to 1982. Intrapartum fetal heart rate monitoring, cesarean section delivery, attempted delivery room resuscitation, and 5-minute Apgar scores greater than 5 were more frequent in 1983 to 1985. Significantly greater neonatal survival was evident for infants 500 to 700 gm birthweight (31%) and 24 to 27 weeks' gestation (45%) in 1983 to 1985, p less than 0.005. Infant birthweight, gestational age, gender, and 5-minute Apgar score, in addition to intrapartum tocolysis use, were predictors of higher survival by stepwise discriminant analysis. At a mean follow-up of 27 months, 13% (6 of 46) born in 1983 to 1985 had major disability compared with 67% (6 of 9) of infants born in 1980 to 1982. There has been a significant increase in survival and improvement in neurodevelopmental follow-up status for infants less than 801 gm birthweight. These improved outcome data should be considered by caregivers providing perinatal management and counseling parents regarding extremely low birthweight infants.

Apgar Score↗
PubMed1990

Safety of intravenous immunoglobulin infusion in neonates at risk for sepsis.

Intravenous immunoglobulin (Gammagard 5%), 500 mg/kg, was given over 3 hours to 10 acutely ill infants with proven or suspected sepsis (treatment group) and 10 clinically stable preterm infants less than 1750 gm birthweight as prophylaxis for sepsis (prevention group). No differences were found in heart rate, respiratory rate, mean arterial blood pressure, or urine output in either group during or following the infusion compared with preinfusion values, except for a small but significant decrease in heart rate postinfusion in the prevention group. Likewise, serum glucose, sodium, serum glutamic oxaloacetic transaminase, and osmolality were unchanged 15 minutes and 6 hours following infusion. Urea nitrogen rose a small but significant amount in both groups. Hemoglobin concentration declined a small but significant amount 15 minutes postinfusion in the prevention group, but returned to baseline by 6 hours postinfusion. There were no changes in white blood cell count or platelet counts in either group. These data indicate that intravenous immunoglobulin in the dose given was associated with no adverse effects. Additional studies are warranted to evaluate the efficacy of these preparations in the treatment and prevention of neonatal septicemia.

Antibodies, Viral↗
PubMed1990

Relationship of maternal to neonatal colonization with coagulase-negative staphylococci.

Infections with coagulase-negative staphylococci (C-S) have become problems of major clinical importance among very low birthweight infants in neonatal intensive care units. Colonization with slime-producing strains of C-S may be a risk factor for these infants in the development of invasive infections. The present study evaluated the maternal genital tract as a possible source for neonatal colonization with C-S. Specific objectives were to determine the incidence of vaginal colonization with C-S in pregnant women with special reference to slime-producing strains and whether transmission of C-S occurs from mother to infant during the process of vaginal delivery. Antenatal vaginal cultures were done on 465 women at different gestations of pregnancy. Additionally, 101 women and their newborn infants were cultured after vaginal delivery. Fifty-one percent of women were colonized with C-S during pregnancy, and no significant differences in colonization rates by trimester were found. Slime-positive isolates from pregnant women increased significantly from the first to the third trimester (40 to 68%; chi-square, 11.21, p less than 0.005). However, the proportion of slime-positive strains among the 30 infants who were colonized with C-S at birth was 40% (12 of 30). Although 30 infants were colonized with C-S at birth, only three were shown to have acquired the organism by maternal transmission determined by similarity of species, biotype, antibiotic sensitivity pattern, slime production, phage type, and plasmid pattern profile. Therefore 27 infants (26% of the total) most likely acquired C-S from environmental sources, including nursery attendants.(ABSTRACT TRUNCATED AT 250 WORDS)

Coagulase↗