Anne Koons

The Apgar Score and Its Components in the Preterm Infant

Objective. The Apgar score is well-characterized in full-term infants but not in premature infants. The objective of this study was to assess the Apgar score in preterm infants with respect to the relationships between the 1- and 5-minute scores, the correlation of the Apgar score with pH and with other variables, and the relationship among the individual Apgar components. Methodology. We recorded Apgar scores at 1 and 5 minutes in a population-based cohort of preterm infants (n = 1105) with birth weight <2000 g, from three intensive care nurseries in central New Jersey. Linear correlation analysis was used to examine the relationship between 1- and 5-minute Apgar scores and between the individual components of the Apgar score. Multiple regression analysis was used to explore the relationship between various perinatal characteristics and the Apgar score, and between pH and Apgar score. Stepwise logistic regression analysis was used to assess the determinants of mortality. Results. The 1-minute Apgar score median (25%, 75%) was 6(4,8) and correlated with the 5-minute score of 8(7,9) atr = .78. Slight but significant differences were seen between male (n = 557) and female (n = 508) infants in the 1-minute (6[4,8] and 7[4,8]) Apgar scores. One- and 5-minute scores of white infants (7[4,8] and 8[7,9]; n = 713) were significantly higher than those of black infants (5[3,7] and 8[6,9]; n = 280). Birth weight and gestational age were both linearly related to both Apgar scores. Low Apgar score (<3 at 1 minute and <6 at 5 minutes) was significantly associated with birth weight, gestational age and mode of delivery. Low arterial blood pH (<7.01) at birth was significantly related to low Apgar score. One hundred fifty-nine infants died; these infants were significantly smaller (983 ± 382 vs 1462 ± 369 g), less mature (27 vs 31 weeks), had lower arterial blood pH (7.20 ± 0.18 vs 7.31 ± 0.11), had lower 1- (3[2,6] vs 7[4,8]) and 5-minute Apgar scores (6[4,8] vs 8[7,9]), and a greater incidence of low Apgar score (32% vs 6%) than did survivors. Conclusions. Among the components of the Apgar score, respiratory effort, muscle tone, and reflex activity correlated well with one another; heart rate correlated less well; and color the least. Our data confirms the limited use of the Apgar score in preterm infants and demonstrates the different responses of the Apgar scores components.

Blood pressure ranges in premature infants. I. The first hours of life

We studied blood pressure in the first hours of life in a cohort of 1105 preterm infants weighing 501 to 2000 gm; these infants represented 83% of all births at these weights that resulted in admission to three intensive care nurseries during a 34-month period between 1984 and 1987. To assess the effects of specific risk factors, we identified 244 healthy infants, 164 infants who received mechanical ventilation but had no other conditions, 47 infants whose only risk factor was the presence of hypertension or preeclampsia in the mother, and 86 infants with depressed Apgar scores regardless of the presence of the other conditions. We documented each infants minimum and maximum systolic (Smin, Smax) and diastolic (Dmin, Dmax) pressures during the first 3 to 6 hours of life. In the healthy group, Smin was 47 mmHg; Smax, 59 mmHg; Dmin, 24 mmHg; and Dmax, 35 mmHg. In the ventilation group, Smin was 41 mmHg; Smax, 57 mmHg; Dmin, 22 mmHg; and Dmax, 35 mmHg. The Smin and Dmin values were both significantly lower in infants who received mechanical ventilation than in healthy infants (p < 0.01). In the maternal hypertension group, Smin was 49 mmHg; Smax, 59 mmHg; Dmin, 25 mmHg; and Dmax, 34 mmHg. Only the Smin value was significantly higher than in healthy infants. In the group with low Apgar scores, Smin was 33 mmHg; Smax, 51 mmHg; Dmin, 19 Hg; and Dmax, 34 mmHg. Thus all these values were significantly lower than in all the other groups (p < 0.05). Of infants with low Apgar scores, 20% to 50% had values below the 5th percentile for healthy infants. Birth weight and gestational age correlated with blood pressure limits only in the infants with low Apgar scores. We conclude that in healthy premature infants the limits of systolic and diastolic blood pressure are independent of birth weight and gestational age. Infants with low Apgar scores tend to have lower pressures, and infants whose mothers have hypertension have higher pressures than infants in the healthy cohort.

Cerebral Vascular Responses to Changes in Carbon Dioxide Tension in Term and Preterm Infants with Apnea

Carbon dioxide (CO2) plays important roles in regulating both respiratory drive and cerebral blood flow. These effects are mediated, in part, by activity of the sympathetic nervous system. We hypothesized that the presence of acute life-threatening events or apnea in term or preterm infants, respectively, would serve as a marker for immaturity of cerebral autonomic innervation and that such infants would display a reduced cerebral vascular response to elevated pCO2. Therefore, we evaluated the cerebral vascular response during CO2 challenge tests in groups of term and preterm infants with primary apnea. In term infants (39 ± 2 weeks gestation) with acute life-threatening events, elevated pCO2 was accompanied by decreasing pulsatility index and increasing mean anterior cerebral blood flow velocity. However, in preterm infants (29 ± 2 weeks’ gestation) with apnea, pulsatility index and anterior cerebral artery flow velocity did not significantly change in response to CO2 supplementation. We conclude that preterm, but not term, infants with apnea exhibit impaired vascular responses to hypercarbia.

Developmental Implications of Head Growth Following Intracranial Hemorrhage

This study examined the association between head size at birth, discharge, and 1 year and developmental outcome at 1 year in preterm infants, with and without intracranial hemorrhages (ICH) or associated periventricular echodensities (PVE). The data indicated that most sick preterm infants with small heads at discharge achieved appropriate head sizes at 1 year. Analyses of the 1-year mental and motor performances of 125 subjects revealed that for subjects who did not develop ICH, appropriate head sizes at birth and discharge were associated with good developmental outcome, whereas infants with small heads (< two standard deviations below the mean for age) before hospital discharge were more likely to show poorer developmental outcome at 1 year. For subjects with ICH, birth and discharge head circumference were not predictive of 1-year developmental status; however, normal head size at 1 year was associated with better outcome. This was true for children with transient PVE as well. However, persistent periventricular echodensities were associated with both mental and motor deficits at 1 year, regardless of head growth.

Prolonged low dose indomethacin for persistent ductus arteriosus.

(31-6 weeks) as those studied by Evans and Archer (one at 28, one at 30, two at 32, and three at 33 weeks). Furthermore our results were substantiated by analysis of ductal flow. Unfortunately Drs Evans and Archer did not utilise the potential of their technique for serial measurement to the full; results were presented in a cross sectional manner, with different numbers studied at each age. Group means were compared when it would have been better to analyse the rate of fall in each individual separately. In truth, neither of these papers can probably come to a definite conclusion about the relative rate of fall of pulmonary arterial pressure in term and preterm babies. However, three potentially useful Doppler techniques have been introduced to neonatology and this discussion helps to clarify some ofthe potential merits and shortcomings of each.

Predicting Developmental Outcome in Preterm Infants 1281

Early and significant correlations between the Bayley Scales of Infant Development and the Stanford-Binet Intelligence Scale (S-B) were noted in a cohort of premature infants (N=215; BW: 1601.3 +/- 707 gms; GA: 31.3 +/- 4 wks) evaluated periodically after hospital discharge. Observers blinded to the clinical status administered the Mental Development Index (MDI) of the Bayley Scales at corrected ages of 6 +/- 1mo (MDI-1;n=144), 12 +/- 2mo (MDI-2;n=63), 14 +/- 4mo (MDI- 3;n=176), and 23 +/- 3mo (MDI-4;n=161). The S-B was administered at 3.8 +/-.7 years. Significant correlations (*P<0.05;**P<0.01; ***P<0.001; ****P<0.0001) between the tests are noted below. From 12 months on, the MDI is increasingly predictive, reinforcing its role as an early diagnostic and therapeutic resource for physicians and families. Table

Prenatal Betamethasone Therapy in the Infant with Birth Weight Below 750 Grams. 963

Betamethasone (B) administration prior to delivery was associated with significantly improved outcome of infants born with birth weight less than 750g. The clinical course of 56 infants (BW 621 +/- 82g, GA 24.9 +/- 1.9 wks) pretreated with a full course of B was compared to 51 control (C) infants (BW 591 +/- 90g; GA 24.1 +/- 2.0 wks). The B group was significantly (p<0.05) heavier and more mature and were more likely to be delivered by Cesarean section (71.2 vs. 28.9%).

THE INFLUENCE OF PRENATAL BETAMETHASONE ON THE MORTALITY AND MORBIDITY OF THE EXTREMELY LOW BIRTH WEIGHT INFANT 941

THE INFLUENCE OF PRENATAL BETAMETHASONE ON THE MORTALITY AND MORBIDITY OF THE EXTREMELY LOW BIRTH WEIGHT INFANT 941

RESCUE SURFACTANT THERAPY IN THE EXTREMELY LOW BIRTH WEIGHT INFANT (ELBW) 2004

To study the mortality and morbidity of the ELBW infant after rescue surfactant (Exosurf) therapy, we examined 542 consecutively born infants below 1000g birth weight before (Period A; 1983-1989) and after (Period B; 1990-1994) surfactant use.

THE INFLUENCE OF PERINATAL EVENTS ON THE NEONATAL OUTCOME OF THE EXTREMELY LOW BIRTH WEIGHT (ELBW) INFANT. 1602

THE INFLUENCE OF PERINATAL EVENTS ON THE NEONATAL OUTCOME OF THE EXTREMELY LOW BIRTH WEIGHT (ELBW) INFANT. 1602