Early-onset sepsis in very low birth weight neonates: a report from the National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

Early-onset sepsis (occurring within 72 hours of birth) is included in the differential diagnosis of most very low birth weight (VLBW) neonates. To determine the current incidence of early-onset sepsis, risk factors for disease, and the impact of early-onset sepsis on subsequent hospital course, we studied a cohort of 7861 VLBW neonates (401 to 1500 gm) admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991-1993).

METHODS

The NICHD Neonatal Research Network maintains a prospectively collected registry on all VLBW neonates born or cared for at participating centers. Data from this registry were analyzed retrospectively.

RESULTS

Blood culture-proven early-onset sepsis was uncommon, occurring in only 1.9% of VLBW neonates. Group B streptococcus was the most frequent pathogen associated with early-onset sepsis (31%), followed by Escherichia coli (16%) and Haemophilus influenzae (12%). Decreasing gestational age was associated with increased rates of infection. Antibiotic therapy for suspected sepsis is frequently initiated at birth in VLBW neonates. Almost half of the infants in this cohort were considered to have clinical sepsis and continued to receive antibiotics for 5 or more days, despite a negative blood culture result in 98% of cases. These findings underscore the difficulty of ruling out sepsis in the symptomatic immature neonate and the special concern for culture-negative clinical sepsis in the face of maternal antibiotic use. Neonates with early-onset sepsis were significantly more likely to have subsequent comorbidities, including severe intraventricular hemorrhage, patent ductus arteriosus, and prolonged assisted ventilation. Although 26% of VLBW neonates with early-onset sepsis died, only 4% of the 950 deaths that occurred in the first 72 hours of life were attributed to infection. For those infants discharged alive, early-onset sepsis was associated with a significantly prolonged hospital stay (86 vs 69 days; p <0.02).

CONCLUSIONS

Early-onset sepsis remains an important but uncommon problem among VLBW preterm infants. Improved diagnostic strategies are needed to enable the clinician to distinguish between the infected and the uninfected VLBW neonate with symptoms and to target continued antibiotic therapy to those who are truly infected.

Late-onset sepsis in very low birth weight neonates: a report from the National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 7861 VLBW (401 to 1500 gm) neonates admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991 to 1993).

METHODS

The NICHD Neonatal Research Network maintains a prospectively collected registry of all VLBW neonates cared for at participating centers. Data from this registry were analyzed retrospectively.

RESULTS

Of 6911 infants who survived beyond 3 days, 1696 (25%) had one or more episodes of blood culture-proven sepsis. The vast majority of infection (73%) were caused by gram-positive organisms, with coagulase-negative staphylococci accounting for 55% of all infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of infection included intubation, respiratory distress syndrome, prolonged ventilation, bronchopulmonary dysplasia, patent ductus arteriosus, severe intraventricular hemorrhage, and necrotizing enterocolitis. Among infants with bronchopulmonary dysplasia, those with late-onset sepsis had a significantly longer duration of mechanical ventilation (45 vs 33 days; p <0.01). Late-onset sepsis prolonged hospital stay: the mean number of days in the hospital for VLBW neonates with and without late-onset sepsis was 86 and 61 days, respectively (p <0.001). Even after adjustment for other complications of prematurity, including intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia, infants with late-onset sepsis had a significantly longer hospitalization (p <0.001). Moreover, neonates in whom late-onset sepsis developed were significantly more likely to die than those who were uninfected (17% vs 7%; p <0.000 1), especially if they were infected with gram-negative organisms (40%) or fungi (28%). Deaths attributed to infection increased with increasing chronologic age. Whereas only 4% of deaths in the first 3 days of life were attributed to infection, 45% of deaths after 2 weeks were related to infection.

CONCLUSIONS

Late-onset sepsis is a frequent and important problem among VLBW preterm infants. Successful strategies to decrease late-onset sepsis should decrease VLBW mortality rates, shorten hospital stay, and reduce costs.

Interlaboratory variability of bilirubin measurements

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

A prospective randomized trial comparing continuous versus intermittent feeding methods in very low birth weight neonates

OBJECTIVE

To compare the effects of continuous versus intermittent feedings on physical growth, gastrointestinal tolerance, and macronutrient retention in very low birth weight infants ( < 1500 gm).

STUDY DESIGN

Very low birth weight neonates stratified by birth weight were randomly assigned to either continuous (24-hour) or intermittent (every 3 hours) nasogastric feedings. Feedings with half-strength Similac Special Care formula were initiated between day 2 and 3 and were advanced isoenergetically to goal. Daily weights, volume/caloric intakes, weekly anthropometric and dynamic skin-fold thickness measurements, and data on feeding milestones and clinical complications were collected. Nitrogen, carbohydrate, and fat balance studies were performed on a subset of male subjects.

RESULTS

Eighty-two neonates with birth weights between 750 and 1500 gm who were born between 27 and 34 weeks of gestation were randomly assigned to continuous (n = 42) and intermittent (n = 40) feeding groups. There were no significant differences in baseline demographics and severity of respiratory distress between groups. There were no significant differences in days to regain birth weight, days to full enteral feedings, days to discharge, and discharge anthropometric measurements between continuously fed and intermittently fed infants, both when evaluated together and according to 250 gm weight intervals. Retention rates of nitrogen, fat, total carbohydrate, and lactose were comparable in the continuously fed (n = 17) and intermittently fed (n = 13) male neonates. Very low birth weight neonates who were fed continuously did not have feeding-related complications.

CONCLUSION

Very low birth weight infants achieve similar growth and macronutrient retention rates and have comparable lengths of hospital stay whether they are fed with continuous or intermittent feedings.

Interlaboratory variability of bilirubin measurements

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

Antenatal phenobarbital therapy and neonatal outcome. I: Effect on intracranial hemorrhage

OBJECTIVE

To evaluate the effect of antenatal phenobarbital (PB) therapy on neonatal intracranial hemorrhage (ICH) in preterm infants.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Single institution study.

SUBJECTS AND INTERVENTIONS

Women in preterm labor ( < 35 weeks' gestation) were assigned to control and treatment groups. The treatment group received 10 mg/kg (maximum, 1000 mg) PB intravenously, followed by 100 mg orally daily, until delivery. Neonates did not receive PB after birth. Head sonograms were performed on days 3, 7, and 14 and at discharge. Hemorrhage was classified as mild, moderate, or severe by a single reader.

OUTCOME MEASURES

Incidence of neonatal ICH in all infants, infants weighing less than 1250 g, and infants of multiple gestations.

RESULTS

The study population comprised 110 women, 60 in the control group and 50 in the PB group. Neonates in the control group (n = 74, including 10 pairs of twins and 2 sets of triplets) were comparable to those in the treatment group (n = 62, including 7 pairs of twins, 1 set of triplets, and 1 set of quadruplets) regarding birth weight, gestational age, and other clinical risk factors for ICH. There was a trend for the incidence of any grade of hemorrhage to be lower in the PB group (22% [14 of 62]) compared with the control group (35% [26 of 74]). Moderate and severe hemorrhages were significantly lower in the PB group (1.6% [1 of 62]) compared with the control group (9.4% [7 of 74]). Among infants weighing less than 1250 g, overall ICH was lower in the PB group (23% [6 of 26]) compared with the control group (51% [18 of 35]). Among multiple-gestation infants, overall ICH was 4.7% (1 of 21) in the PB group, compared with 31% (8 of 26) in the control group.

CONCLUSIONS

Antenatal PB therapy results in a significant decrease in moderate and severe ICH in infants born at less than 35 weeks' gestation. Antenatal PB therapy also resulted in a decrease in the incidence of all grades of ICH in infants weighing less than 1250 g and infants born of multiple gestations.

Antenatal phenobarbital therapy and neonatal outcome. II: Neurodevelopmental outcome at 36 months

OBJECTIVE

To evaluate the effect of antenatal phenobarbital (PB) therapy on neurodevelopmental outcome at 36 months.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Single-institution study. SUBJECT AND INTERVENTIONS: Children born to women who participated in the study evaluating the effect of antenatal phenobarbital (PB) on neonatal intracranial hemorrhage were prospectively followed to 3 years of age.

OUTCOME MEASURES

Physical growth, neurologic examinations, and developmental testing (McCarthy Scales of Children's Abilities). Comparisons between groups were made on all children and those born to multiple gestations.

RESULTS

Forty-one children born to women who received 10 mg/kg PB before delivery and 55 children in the control group were evaluated. Three children, all in the control group, had growth parameters (height, weight, and head circumference) below the fifth percentile. The McCarthy General Cognitive Index (standard, 100 +/- 16) was 93 +/- 20 in the PB group and 85 +/- 18 in the control group. The subscores tended to be higher in the PB group than in the control group, with higher quantitative scores in the PB group (44 +/- 11 vs 39 +/- 8). Neurologic deficits were noted in 2 of 41 in the PB group and in 6 of 55 in the control group.

CONCLUSIONS

Infants born to women who received antenatal PB therapy had similar neurodevelopmental outcomes as infants born to women who did not receive PB. No adverse effects of PB exposure were detected.

Prenatal and perinatal risk and protective factors for neonatal intracranial hemorrhage. National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

To identify prenatal and perinatal risk and protective factors for grade III and IV intracranial hemorrhage (ICH) in 4795 singleton infants (weight, < or = 1500 g).

METHOD

Prenatal and perinatal risk and protective factors for ICH were examined initially by univariate analysis and adjusted for year of birth, followed by multivariate logistic regression analysis that adjusted simultaneously for the effects of year of birth and prenatal and perinatal characteristics.

SETTING

Seven tertiary care neonatal-perinatal centers.

RESULTS

By univariate analysis, African-American race, prenatal care, older maternal age, hypertension or preeclampsia, antenatal steroid administration, cesarean section delivery, increasing birth weight, increasing gestational age, and female gender of the infant were protective prenatal or perinatal factors. Antepartum hemorrhage, the presence of labor, and breech presentation were perinatal factors that were associated with an increased risk of ICH. By using staged logistic regression, a model of combined prenatal and perinatal characteristics that influenced grade III and IV ICH was developed. Significant protective factors against ICH included a complete course of antenatal steroid therapy, African-American maternal race, female gender of the infant, hypertension or preeclampsia with no antepartum hemorrhage, increasing gestational age, and increasing birth weight.

CONCLUSION

Antenatal steroid administration is a therapeutic intervention that is associated with a decreased risk for neonatal grade III and IV ICH.

Adenosine infusion improves oxygenation in term infants with respiratory failure

OBJECTIVES

Adenosine infusion causes selective pulmonary vasodilation in fetal and neonatal lambs with pulmonary hypertension. We investigated the effects of a continuous infusion of adenosine on oxygenation in term infants with persistent pulmonary hypertension of newborn (PPHN).

DESIGN

A randomized, placebo-controlled, masked trial comparing the efficacy of intravenous infusion of adenosine to normal saline infusion over a 24-hour period.

SETTING

Inborn and outborn level III neonatal intensive care units at a university medical center.

PARTICIPANTS

Eighteen term infants with PPHN and arterial postductal PO2 of 60 to 100 Torr on inspired O2 concentration of 100% and optimal hyperventilation (PaCO2 <30 Torr) were enrolled into the study. Study infants were randomly assigned to receive a placebo infusion of normal saline, or adenosine infusion in doses of 25 to 50 microg/kg/min over a 24-hour period.

PARTICIPANTS

Eighteen term infants with PPHN and arterial postductal PO2 of 60 to 100 Torr on inspired O2 concentration of 100% and optimal hyperventilation (PaCO2 <30 Torr) were enrolled into the study. Study infants were randomly assigned to receive a placebo infusion of normal saline, or adenosine infusion in doses of 25 to 50 microg/kg/min over a 24-hour period.

RESULTS

Nine infants each received adenosine or placebo. The two groups did not differ in birth weight, gestational age, or blood gases and ventilaator requirements at the time of entry into the study. Four of nine infants in the adenosine group and none of the placebo group had a significant improvement in oxygenation, defined as an increase in postductal PaO2 of > or =20 Torr from preinfusion baseline. The mean PaO2 in the adenosine group increased from 69 +/- 19 at baseline to 94 +/- 15 during 50 microg/kg/min infusion rate of adenossine and did not change significantly in the placebo group. Arterial blood pressure and heart rate did not change during the study in either group. The need for extracorporeal membrane oxygenation, incidence of bronchopulmonary dysplasia, and mortality were not different in the two groups.

CONCLUSION

Data from this pilot study indicate that adenosine infusion at a dose of 50 microg/kg/min improves PaO2 in infants with PPHN without causing hypotension or tachycardia. Larger trials are needed to determine its effects on mortality and/or need for extracorporeal membrane oxygenation in infants with PPHN.

Pharmacokinetics of erythropoietin following single-dose subcutaneous administration in preterm infants

The pharmacokinetics of recombinant human erythropoietin was studied in 12 very low birth weight preterm infants < 32 weeks of gestation after subcutaneous administration of 300 IU/kg at a postconceptional age of 34 (32-37) weeks and a weight of 1,505 (1330-1,740)g (median and range). The administration of recombinant human erythropoietin produced a rapid increase in serum erythropoietin levels with a peak level of 362.8 mIU/ml at 8.9 h. The area under the curve was 8,177.5 (4,597.1-15,453.0) mIU/ml/h, the absorption half-life was 5.5 (1.6-6.6) h, the elimination half-life was 7.9 (5.6-19.4) h, and the residence time was 19.6 (5.1-32.6) h (all values reflect median and range). There was no significant correlation between absorption and elimination half-life of erythropoietin and birth weight, gestational age, sex, and age and weight of the infants at the time of administration of erythropoietin. Based on absorption and elimination kinetics, the dosing interval for subcutaneous administration must not be < 48 h.

Very-low-birth-weight outcomes of the National Institute of Child Health and Human Development Neonatal Research Network, May 1991 through December 1992

OBJECTIVES

Our goals were to determine the mortality risk for infants weighing 501 to 1500 gm according to gestational age, birth weight, and gender and to document birth weight-related changes in mortality and morbidity over a 5-year time period.

STUDY DESIGN

In this observational study perinatal data were prospectively collected by the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from May 1991 through December 1992 and compared with the corresponding data from 1987 through 1990. Standard definitions were used to record sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death.

RESULTS

The 1991 and 1992 cohort included 4279 in-born infants. Among their mothers 10% were < 18 years old; 55% were black, 31% were white, and 11% were Hispanic; 14% had received no prenatal care; and 20% had received antenatal corticosteroids. Multiple gestations accounted for 20% of the births. Fifty percent of the infants were delivered by cesarean section. During 1991 and 1992 the overall survival for infants weighing 501 to 1500 gm at birth was 81%, compared with 74% in 1987 and 1988. Survival at birth weight 501 to 750 gm was 44%; it was 81% at 751 to 1000 gm, 92% at 1001 to 1250 gm, and 95% between 1251 and 1500 gm. Female infants had a significantly greater chance of surviving than male infants at similar birth weights and gestational ages. At any given gestational age, smaller infants were less likely to survive. Survival in all birth weight categories increased between 1987 and 1992, without accompanying increases in medical morbidity. Major morbidity increased with decreasing birth weight and included late-onset septicemia 22%, chronic lung disease (oxygen dependence at 36 weeks' corrected age) 18%, severe intraventricular hemorrhage (grades III and IV) 11%, and necrotizing enterocolitis 5%. Twelve percent of all infants were treated with corticosteroids for chronic lung disease, including 36% of infants who were oxygen dependent at age 28 days. The mean length of hospital stay was 69 days for survivors and 18 days for infants who died.

CONCLUSIONS

Mortality for infants between 501 and 1500 gm at birth has declined over the past 5 years. There are interactions between birth weight, gestational age, gender, and survival rate. This increase in survival was not accompanied by an increase in medical morbidity.

Double phototherapy with high irradiance compared with single phototherapy in neonates with hyperbilirubinemia

The purpose of this study is to compare the effectiveness of double phototherapy versus single conventional phototherapy in decreasing serum bilirubin levels in jaundiced neonates. Forty-two preterm infants who were less than 37 weeks' gestational age and less than 2000 g birthweight with nonhemolytic jaundice were alternately assigned to double phototherapy (n = 19) (Biliblanket, Ohmeda with irradiance of 33 to 35 microW/cm2/nm in addition to single conventional phototherapy with combination of three or four special blue and white lamps with irradiance of 7 to 9 microW/cm2/nm) or to single conventional phototherapy (n = 23) based on elevated serum bilirubin levels in the first week of life. Phototherapy was initiated at specific bilirubin levels in three weight stratifications. The groups were similar in clinical characteristics at study entry. The decrease in serum bilirubin levels was very significant in the double phototherapy group at 8 hours after the therapy (-29 +/- 18.8 versus 8.5 +/- 27 mumol/L; P < 0.001), at 16 hours after the therapy (-49.6 +/- 15.4 versus 3.4 +/- 39 mumol/L; p < 0.001), and at 24 hours after therapy (-71.8 +/- 18.8 versus -3.4 +/- 32.5 mumol/L; p < 0.001) compared with the conventional phototherapy group. The time taken for bilirubin levels to fall below the threshold level was 55 +/- 41 hours in the single group and 14 +/- 6 hours in the double group (p < 0.001). Double phototherapy was well tolerated. The Biliblanket when used in conjunction with single conventional phototherapy resulted in a faster decrease of serum bilirubin.(ABSTRACT TRUNCATED AT 250 WORDS)

Mineral excretion following furosemide compared with bumetanide therapy in premature infants

Mineral excretion following single doses of furosemide were compared with bumetanide in a random cross-over trial in 17 premature infants. The mean birthweight and gestational age were 889 +/- 85 g and 27 +/- 2 weeks. Following furosemide therapy, significantly higher chloride losses and urine volumes were noted in the first 8-h period compared with the second or third 8-h periods. Following bumetanide therapy, sodium, calcium, and chloride losses and urine volumes were significantly higher in the first 8 h compared with the second or third 8-h periods. Hourly sodium and chloride losses were significantly lower following bumetanide than furosemide during the first two 8-h periods. During the final 8-h period sodium, potassium, chloride, and calcium losses were significantly lower following bumetanide than following furosemide. Sodium loss per urine volume was lower with bumetanide than furosemide but calcium loss tended to be higher. Hence, bumetanide does not appear to be a calcium-sparing diuretic following single-dose therapy.

Plasma immunoreactive endothelin-1 concentration in cord blood of normal term neonates

Plasma immunoreactive endothelin-1 (ir-ET-1) concentrations in cord blood of 20 term infants were measured by radioimmunoassay. The mean (+/- SEM) ir-ET-1 concentration was 1.04 +/- 0.29 pg/mL. There was no relationship between ir-ET-1 concentrations and race, sex, mode of delivery, and prenatal characteristics, such as cocaine exposure. The current methodologies were reviewed in an effort to explain the differences in ET-1 concentrations reported in various studies.

Very-low-birth-weight outcomes of the National Institute of Child Health and Human Development Neonatal Network, November 1989 to October 1990

OBJECTIVE

Our purpose was to describe the neonatal outcomes of 1804 very-low-birth-weight (< or = 1500 gm) infants delivered between November 1989 and October 1990 in the participating centers of the National Institute of Child Health and Human Development Neonatal Research Network.

STUDY DESIGN

In an observational study sociodemographic, pregnancy, and delivery data were collected soon after birth, and neonatal and outcome data at discharge, at 120 days, or at death.

RESULTS

Maternal and birth weight characteristics included 64% black, 29% white; 71% single mothers; 18% no prenatal care; 17% antenatal steroids; and 12% multiple gestations. Birth weight distributions included 18% weighing 501 to 750 gm, 23% 751 to 1000 gm, 28% 1001 to 1250 gm, and 31% 1251 to 1500 gm. Survival was 39% at < 751 gm birth weight, 77% at 751 to 1000 gm, 90% at 1001 to 1250 gm, and 93% at 1251 to 1500 gm. Survival was 15% to 18% at < or = 23 weeks' gestation, 54% at 24 weeks, 59% at 25 weeks, and 71% at 26 weeks. Surfactant was administered to 45% of the 56% of infants with respiratory distress syndrome. Morbidity, including intraventricular hemorrhage (40%), septicemia (24%), symptomatic patent ductus arteriosus (22%), and necrotizing entercolitis (8%), increased with decreasing birth weight. Oxygen was administered for > or = 28 days to 82% of < 751 gm infants, 49% of 751 to 1000 gm infants, and 10% of > 1001 gm infants. Steroids were administered to 28% of infants who required oxygen for > or = 28 days. Mean hospital stay was 62 days for survivors and 18 days for infants who died. There were large intercenter variations in mortality and morbidity.

CONCLUSION

Mortality and morbidity in very-low-birth-weight infants improved in 1989 to 1990 without an increase in morbidity or length of hospital stay. The threshold of the improved survival was > or = 24 weeks and 601 to 700 gm. Although such data are reassuring, the rate of major morbidity in < 1001 gm birth weight infants continues to be high.

Bilirubin production in healthy term infants as measured by carbon monoxide in breath

To describe total bilirubin production in healthy term infants, we measured the end-tidal breath CO, corrected for ambient CO (ETCOc), with an automated sampler and electrochemical (EC) CO instrument. For infants of mothers with a negative Coombs' test, the ETCOc was 1.3 +/- 0.7 microL/L (n = 397) and the serum bilirubin on day 3 postpartum was 73 +/- 35 mg/L (n = 381). In contrast, the ETCOc for infants with ABO or Rh incompatibility, a positive direct Coombs' test, and bilirubin &gt; 130 mg/L (n = 9) was significantly higher, 1.8 +/- 0.8 microL/L, than for those who had a positive Coombs' test result but whose bilirubin was &lt; or = 130 mg/L (n = 12), 1.0 +/- 0.5 microL/L (P &lt; 0.05). At 2 to 8 h postpartum seven term babies from mothers with insulin-dependent diabetes had ETCOc of 1.8 +/- 0.7 microL/L, significantly higher than that in the other term infants [1.3 +/- 0.7 microL/L (n = 390), P &lt; 0.04]. Their bilirubin concentration at 72 +/- 12 h was also higher: 121 +/- 45 mg/L (n = 7) vs 73 +/- 34 mg/L (n = 374; P = 0.03). We conclude that ETCOc measurements may be helpful in understanding the mechanisms of jaundice in healthy term infants in a variety of conditions.

Semiportable electrochemical instrument for determining carbon monoxide in breath

Measurements of carbon monoxide (CO) in breath can be used for the diagnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neonatal Research Network Centers of the National Institute of Child Health and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activate carbon filter to an electrochemical (EC) sensor having a sensitivity of 0.10 +/- 0.01 V per 1 microL/L CO in air. The electronically processed sensor signal is displayed on a digital multimeter. For a typical end-tidal CO measurement, corrected for inhaled CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath samples from 108 healthy, 1-day-old infants of nonsmoking mothers compared favorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 vs 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC+0.13 (r2 = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtained by the more difficult to perform GC assay.

Bilirubin production in healthy term infants as measured by carbon monoxide in breath

To describe total bilirubin production in healthy term infants, we measured the end-tidal breath CO, corrected for ambient CO (ETCOc), with an automated sampler and electrochemical (EC) CO instrument. For infants of mothers with a negative Coombs' test, the ETCOc was 1.3 +/- 0.7 microL/L (n = 397) and the serum bilirubin on day 3 postpartum was 73 +/- 35 mg/L (n = 381). In contrast, the ETCOc for infants with ABO or Rh incompatibility, a positive direct Coombs' test, and bilirubin > 130 mg/L (n = 9) was significantly higher, 1.8 +/- 0.8 microL/L, than for those who had a positive Coombs' test result but whose bilirubin was < or = 130 mg/L (n = 12), 1.0 +/- 0.5 microL/L (P < 0.05). At 2 to 8 h postpartum seven term babies from mothers with insulin-dependent diabetes had ETCOc of 1.8 +/- 0.7 microL/L, significantly higher than that in the other term infants [1.3 +/- 0.7 microL/L (n = 390), P < 0.04]. Their bilirubin concentration at 72 +/- 12 h was also higher: 121 +/- 45 mg/L (n = 7) vs 73 +/- 34 mg/L (n = 374; P = 0.03). We conclude that ETCOc measurements may be helpful in understanding the mechanisms of jaundice in healthy term infants in a variety of conditions.

Semiportable electrochemical instrument for determining carbon monoxide in breath

Measurements of carbon monoxide (CO) in breath can be used for the diagnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neonatal Research Network Centers of the National Institute of Child Health and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activate carbon filter to an electrochemical (EC) sensor having a sensitivity of 0.10 +/- 0.01 V per 1 microL/L CO in air. The electronically processed sensor signal is displayed on a digital multimeter. For a typical end-tidal CO measurement, corrected for inhaled CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath samples from 108 healthy, 1-day-old infants of nonsmoking mothers compared favorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 vs 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC+0.13 (r2 = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtained by the more difficult to perform GC assay.

Post extracorporeal membrane oxygenation single photon emission computed tomography (SPECT) as a predictor of neurodevelopmental outcome

OBJECTIVE

To determine the incidence and site of single photon emission computed tomography scan (SPECT) abnormalities in survivors of neonatal extracorporeal membrane oxygenation and to evaluate the efficacy of SPECT scan as a predictor of neurodevelopmental outcome in these infants.

SETTING

Tertiary care neonatal intensive care unit in Detroit, MI.

PATIENT POPULATION

Survivors of neonatal extracorporeal membrane oxygenation who had a SPECT scan of the brain performed after decannulation and before their discharge from the neonatal intensive care unit were included if they had at least 12 months of follow-up in our developmental assessment clinic.

OUTCOME MEASURES

The neurological outcome was reported as normal, suspect, and abnormal on the basis of neurological examination and developmental milestones. The developmental outcome was assessed by Bayley mental development index or McCarthy general cognitive index scores.

RESULTS

A total of 59 patients met study criteria. SPECT scan abnormalities were noted in 45 (76%) infants. Global hypoperfusion was the most frequent abnormality followed closely by bilateral focal perfusion defects. The distribution of perfusion abnormalities was not significantly different for right and left hemispheres. Among 14 infants with normal SPECT scans, 13 infants had normal neurological outcome and all had a normal developmental outcome. Of the 45 infants with an abnormal SPECT scan, 7 infants had an abnormal neurological outcomes and 4 infants had an abnormal developmental outcome. SPECT scan abnormalities had no significant correlation with neurodevelopmental outcome of these infants.

CONCLUSION

Although a normal SPECT scan was more likely to predict a normal neurodevelopmental outcome, an abnormal SPECT scan did not predict an abnormal outcome in these infants.

Effects of alcohol use, smoking, and illicit drug use on fetal growth in black infants

STUDY OBJECTIVES

To compare the effects of prenatal exposure to alcohol, smoking, and illicit drugs on birth size.

DESIGN

Prospective, longitudinal correlational study, with statistical control for confounding.

PARTICIPANTS

Four hundred seventeen black infants. Mothers recruited at first prenatal clinic visit on the basis of moderate-to-heavy use of alcohol or cocaine or both, plus a 5% random sample of lower-level drinkers and abstainers.

MAIN RESULTS

Alcohol, smoking, opiates, and cocaine were each correlated with smaller birth weight, length, and head circumference (median r = -0.21; p < 0.001). However, when all four substances, gestational age, and six covariates were controlled statistically, birth weight related only to alcohol and smoking (p < 0.05), length only to alcohol (p < 0.05), and head circumference only to opiates (p < 0.01). Although smoking affected birth weight at all levels of exposure, a larger deficit was seen in relation to heavy drinking (509 gm) than to heavy smoking (269 gm). Alcohol and smoking did not affect birth size synergistically, and their effects were seen primarily in infants of women more than 30 years of age.

CONCLUSIONS

The association of reduced birth weight and length with illicit drug use may be a consequence of simultaneous exposure of the fetus to alcohol and smoking. Opiate exposure is specifically related to reduced head circumference, and the effect of cocaine on birth size is primarily an indirect consequence of shorter gestation and poorer maternal nutrition.

Feasibility of invasive monitoring of intracranial pressure in term neonates

Seven term neonates with encephalopathy resulting from asphyxia and/or intracranial hemorrhage underwent invasive monitoring of intracranial pressure through the epidural or intracerebral space. The average age (in hours) at insertion of the monitor was 27 h in the 3 neonates with asphyxia and 70 h in the 4 neonates with hemorrhage. Intracranial hypertension was noted in 6 neonates. The management of the hypertension included hyperventilation followed by mannitol for pressures that were sustained above 20 mmHg and pentobarbital for pressures above 30 mmHg. The duration of the hypertension varied in 5 neonates from 4 to 72 h, while in the remaining neonates, the pressure remained elevated until death at 70 h. All 4 survivors with intracranial hemorrhage have minimal neuromotor deficits on follow up and 2 survivors with asphyxia have cognitive deficits and are microcephalic. From this small series, it appears that in the management of term neonates with intracranial hemorrhage, monitoring of intracranial pressure should be considered.

A multicenter randomized trial comparing two surfactants for the treatment of neonatal respiratory distress syndrome. National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

To compare the efficacy of two surfactants, Exosurf Neonatal (Burroughs Wellcome Co.) and Survanta (Ross Laboratories), for the treatment of neonatal respiratory distress syndrome.

DESIGN

Multicenter randomized trial.

SETTING

Eleven tertiary care university neonatal intensive care units participating in the National Institute of Child Health and Human Development Neonatal Research Network.

PATIENTS

Newborn infants (n = 617) weighing 501 to 1500 gm with respiratory distress syndrome who were receiving assisted ventilation with 30% oxygen or more within 6 hours of birth were enrolled between January 1991 and January 1992.

INTERVENTIONS

Infants were randomly assigned to receive up to four intratracheal doses of either Exosurf Neonatal (n = 309) or Survanta (n = 308).

MAIN OUTCOME MEASURES

The occurrence of death or bronchopulmonary dysplasia 28 days after birth and the average fraction of inspired oxygen (FIO2) and mean airway pressure (MAP) during the first 72 hours after treatment.

RESULTS

Death or bronchopulmonary dysplasia occurred in 67% of the infants in the Exosurf group and 62% of those in the Survanta group (adjusted relative risk, 1.07; 95% confidence interval, 0.96 to 1.20). During the 72 hours after the first surfactant dose, the average FIO2 (+/- SEM) was 0.50 +/- 0.01 for Exosurf and 0.42 +/- 0.01 for Survanta (difference, 0.08; 95% confidence interval, 0.05 to 0.11); the average MAP (+/- SEM) was 7.64 +/- 0.21 cm H2O for Exosurf and 6.93 +/- 0.21 cm H2O for Survanta (difference, 0.71 cm H2O; 95% confidence interval, 0.13 to 1.29 cm H2O). There was no difference between the groups in the incidence of other neonatal morbidities or in the duration of hospitalization, assisted ventilation, or supplemental oxygen administration.

CONCLUSION

We found no difference between treatment groups in the incidence of death or bronchopulmonary dysplasia, although we did observe a difference in the initial response to treatment as measured by FIO2 and MAP.