Mark A Pearlman

Neonatal mortality: an analysis of the recent improvement in the United States.

To test the hypothesis that the recent substantial decline in the United States neonatal mortality rate (20.0/1000 in 1950 to 11.6/1000 in 1975) is associated with improvements in perinatal medical care, we examined this change in relation to the two primary components which determine neonatal mortality: birthweight distribution and birthweight-specific mortality. No improvement in the weight distribution of U.S. live births has occurred during this 25-year period, indicating that the change in neonatal mortality is attributable to improved survival for one or more birthweight groups. Decline in the mortality rate in the first 15 years was slow; three-fourths of the decline in the entire 25-year period occurred since 1965. With the exception of perinatal medical care, factors known to affect survival at a given birthweight have not changed in prevalence in the 25-year period. It is a plausible hypothesis that improved perinatal medical care is a major factor in declining neonatal mortality in the U.S.

The very low-birth-weight rate: Principal predictor of neonatal mortality in industrialized populations

We have examined the relationship between the rate of very low-birth-weight deliveries in a population and the neonatal mortality of that population on three ecologic levels: in one hospital over a 12-year span; among the 50 states and the District of Columbia; and among 13 industrialized nations. In each of the three sets of populations the VLBW rate is an excellent predictor of neonatal mortality, accounting for about three-quarters of the variance in the outcome in all of the populations studied. The relatively high neonatal mortality of the United States as compared to that in some other industrialized nations is primarily attributable to its disadvantageous birth-weight distribution. Holding the adverse birth-weight distribution constant, the United States appears to do better than most of these nations in neonatal mortality. The weight distribution of live births in any population is closely linked to indices of social class. Survival of infants at a given birth weight, however, might well be a function of perinatal care. Since weight-specific mortality rates for populations are not widely available, examination of the variance in neonatal mortality rates once the VLBW rate is held constant might be a first step in comparing the quality of medical care for newborn infants among different populations.

The Association of Kernicterus with Bacterial Infection in the Newborn

A total population of 29,395 neonates cared for in the six-year period from 1971 to 1976 was reviewed for evidence of autopsy-proven kernicterus. A total of 327 neonates died and 232 were autopsied. The only cases of kernicterus occurred in four near-term infants with antemortem proven sepsis. All four of these infants weighed more than 2,200 gm and were delivered after gestations of either 36 or 37 weeks. These cases of kernicterus occurred during a period when more aggressive management of hyperbilirubinemia in low-birth-weight infants had apparently eliminated immaturity as a predisposing factor in the development of kernicterus, uncovering bacterial infection as the major remaining etiologic co-factor.

Nasal airway blockage caused by displaced premaxilla mimicking posterior pharyngeal flap obstruction.

Signs of nasal airway obstruction, ranging from hyponasality, snoring, and inability to blow the nose to cardiorespiratory compromise, have been reported after posterior pharyngeal flap surgery. In some cases the symptoms are severe enough to require take-down or revision of the flap. Polysomnography has been used to document obstruction to nasal airflow and may be a guide in selecting patients for flap revision. This case report points out that in certain patients a particular coexisting anatomic abnormality--the locked-out premaxilla--may predispose patients to this symptom complex. In such patients flap revision may not relieve the symptoms, and careful evaluation of the lateral pharyngeal ports is recommended.

1477 PNEUMOCARDIOGRAMS OF PREMATURE INFANTS AT DISCHARGE

Pneumocardiograms (PCG) are utilized in many hospitals to decide which premature infants are to be discharged on monitors. This is done despite the fact that PCGs have not been shown to be predictive, and no normal PCG values have been established in this population. With these problems in mind, a population of premature infants was studied over a 365-day period just prior to their discharge from a Level III Perinatal Center. The only premature infants excluded were those who did not tolerate weaning from theophylline. None of the 140 subjects were on theophylline at the time of their recordings. Analysis was performed by a computer system (Pediatric Diagnostic Service). The mean gestational age for the patients was 32.8 wks (range:26-36) as determined by modified Dubowitz examination. The mean birth weight was 1740 Gm (range:580-2940). The mean postconceptual age (PCA) at the time of recording was 37.1 wks. Preliminary data analysis has revealed a mean total periodic breathing (PB) of 18.3 min, representing a mean 3.04% of sleep time (ST) for the entire population. The mean apnea density (AD6) was 1.29%. No significant differences were noted in the mean heart rate, respiratory rate, AD6, total PB, and ST in infants >36 wks PCA vs infants ≤36 wks PCA. At all PCAs, no significant differences were found in those same parameters between males and females. Bradycardias (<80 BPM) occurred in 23 infants. Eleven children had apneic episodes >15 seconds; none had apnea ≥20 seconds.

577 DECREASED FETAL ACTIVITY: A POSSIBLE INDICATION OF SUSCEPTIBILITY TO SIDS

Over the past decade, obstetricians have begun to utilize maternal perception of fetal movements in utero as a measurement of fetal well-being. Some have speculated that fetal movements may be a qualitative measure of placental perfusion. Recent findings of brainstem gliosis in victims of Sudden Infant Death Syndrome (SIDS) and other indicators of deficient brainstem function have led Naeye and others to postulate that intrauterine hypoxemia may be an important prenatal factor in such children. The possible correlation between decreased fetal movements and intrauterine hypoxemia led us to question mothers of infants who died of SIDS, as well as mothers of infants with observed apnea and cyanosis, about the movements of their children prior to delivery. A significant decrease in fetal activity was recorded only if there was a total absence of activity for 24 consecutive hours or longer during the pregnancy. Forty percent (8/20) of SIDS victims were retrospectively recalled by their mothers to have decreased intrauterine activity. Similar questioning of mothers of “near miss” infants led to a 43% (59/137) response indicative of an absence of fetal activity for at least 24 hours. Clearly this represents a very significant minority of the SIDS population. A prospective study of infants exhibiting decreased fetal activity is being designed to test this hypothesis. Identification of such previously unrecognized “at risk” infants may be effective in helping to prevent SIDS deaths.

576 EPIDEMIOLOGY OF SIDS: TWO POPULATIONS AT RISK?

Descriptive epidemiologic studies of Sudden Infant Death Syndrome (SIDS) have not helped elucidate possible causes but have defined population characteristics that must be addressed by prospective theories. Many such studies have had poorly defined populations. Careful pathologic and statistical studies are still needed to characterize this population. In New Jersey, 826 infants died of SIDS from 1/1/76 to 12/31/81. A State law mandating autopsies in such cases has led to an autopsy rate in excess of 98%. A match of birth and death certificates was available for 767 such deaths over this six-year period. Significant findings included the peak age at death between 1 and 2 mo. and a mean age at death of less than 2 mo. The incidence of SIDS in the non-white population (NWP) (3.17/1,000 LB) was significantly greater than in the white population (WP) (0.89/1,000 LB). The male predominance was present in the WP (250 males/388) but not in the NWP (189 males/379). The well-described seasonal variation was noted but was entirely explained by a significant increase only in the males. Significantly more children ≥3 mo. of age died in the winter months. This was not true of infants <3 mo. of age at the time of death. This analysis suggests that victims of SIDS may represent two distinct populations: a group of younger infants without male predominance and a second group of older infants containing significantly more males who die in winter months when respiratory infections are more common.

365 AN APPROACH TO THE EVALUATION OF NEONATAL MORTALITY RATES (NMR)

The role of improved neonatal care in the recent reduction in the U.S. NMR remains unclear. Although many socio-demographic factors affect the NMR, these appear to have little effect once birth weight (BW) is held constant, thus making BW-specific NMRs legitimate indicators of medical care and ideal for comparison. Most states, however, at present do not link infant birth and death records and thus cannot generate BW-specific NMRs.We have found that a simple risk-adjusting index, the relationship between the NMR and the incidence of very-low-birth-weight infants (≤1500 grams, VLBW) has enabled us to assess the effectiveness of care at our institution during a period of fluctuating NMRs (AJDC 130:842, 1976). Annual changes in the NMR at our institution correlate strongly with annual variations in the incidence of VLBW newborns. Analysis of the relationship between these two variables, however, showed a decline over the past ten years toward a lower NMR for a given VLBW rate, indicating improving neonatal care.This index has been applied to 1974 NMR and VLBW rate data from each of the 50 states and Washington, D.C.. Significant deviation of some states from the regression line linking the two variables is likely to be a better indicator of statewide neonatal care than the crude NMR.

1008 THE ASSOCIATION OF KERNICTERUS (KI) WITH BACTERIAL SEPSIS

The only cases of KI detected at autopsy in neonates at this institution from 1971 through 1976 occurred in 3 infants with antemortem culture proven sepsis. During this period there were 14,210 deliveries, 387 transferred-in babies, 250 neonatal deaths and 178 autopsies. All 3 of the infants with KI weighed more than 2250 grams and had gestational ages of 36 or 37 weeks. Group B beta hemolytic streptococcal sepsis and meningitis was diagnosed in one infant, but the baby was never icteric. The second infant developed Klebsiella sepsis following spontaneous gastric perforation. The peak total serum bilirubin concentration (SBC) in this baby was 8.6 mg/dl. The third infant manifested E.coli sepsis at 8 hours of age and deteriorated despite appropriate antibiotic therapy; the peak total SBC was 15.6 mg/dl. The direct-reacting SBC in cases 2 and 3 never exceeded 1 mg/dl. All Apgar scores were at least 7 at 1 minute and 9 at 5 minutes.During this period of time only 4 cases (3 with KI) were documented in which sepsis was proven prior to death and a subsequent autopsy was performed. The 3 infants with KI all died with their infection as the primary cause of death. The infant without KI, a 32 week 1850 gram baby, died of a massive CNS hemorrhage. This suggests that persistant bacterial sepsis may be a critical predisposing factor in the development of KI even in the presence of low serum bilirubin concentrations.

456 CONTINUOUS NASOGASTRIC INFUSION (CNGI): A SAFE AND EFFECTIVE WAY TO FEED THE VLBW INFANT

CNGI was evaluated as an alternative to transpyloric or intravenous feeding. Forty three consecutive infants weighing less than 1251 grams were fed Similac PM 60/40 24 cal/ounce or breast milk by the intragastric route: 3 by intermittent gavage and 40 by CNGI. Three infants on CNGI died from respiratory disease in the first week of life. Of the remaining 37 infants, 2 developed intermittent non-specific abdominal distension and 35 remained asymptomatic. Mean fluid and caloric intakes of the 35 asymptomatic infants were 132 ± 20 ml/kg/day and 99 ± 20 cal/kg/day on the fifth day of feeding and 166 ± 18 ml/kg/day and 133 ± 19 cal/kg/day on the tenth day of feeding. Thirty one infants gained weight as expected from the Dancis Growth Curves. None of the 37 infants developed necrotizing enterocolitis or aspiration pneumonia. There was no difference in fluid or caloric intake or symptoms between those infants on respirators (n=19) and those not on ventilatory support (n=18). Four infants on respirators failed to grow adequately despite receiving at least 120 cal/kg/day, suggesting an increased caloric requirement rather than a failure in technique. This experience demonstrated that CNGI is an effective and safe method of feeding even the seriously ill VLBW infant; transpyloric and intravenous alimentation are rarely required.