Jonelle Rowe

Development of the immune system in very low birth weight (less than 1500 g) premature infants: concentrations of plasma immunoglobulins and patterns of infections.

ABSTRACT. Plasma immunoglobulin concentrations of premature infants of birth weight less than 1500 g were measured longitudinally from birth to 10 months chronological age. Infants were divided into two groups based on gestational age (group I: 25–28 wk; group II: 29–32 wk). In the 1st wk of life, plasma IgG levels correlated with gestational age (r = 0.5, p < 0.001). At 3 months chronological age, the geometric mean plasma IgG levels were 60 mg/dl in group I and 104 mg/dl in group II infants. Most infants remained hypogammaglobulinemic at 6 months with seven of 11 infants in group I and 13 of 21 infants in group II having plasma IgG levels below 200 mg/dl. In the 1st wk of life, plasma IgM concentrations were 7.6 and 9.1 mg/dl in groups I and II, respectively. They rose to 41.8 and 34.7 by 8 to 10 months of life. Plasma IgA concentrations were comparable for groups I and II in the 1st wk of life (1.2 and 0.6 mg/dl, respectively), but at 1 month of age group I infants had a transient increase in IgA which was not seen in the group II infants (4.5 versus 1.9 mg/dl, respectively, p < 0.02). This transient elevation in IgA did not correlate with type or route of feeding or amounts of transfused blood. Group I and group II infants had comparable rates of infections prior to discharge from the nursery (p = 0.27). After discharge, the 43 preterm infants followed until 10 months chronological age had a significantly higher incidence of infections than 41 term infants (p = 0.04). In addition, the preterm infants had more lower respiratory infections after discharge than term infants (14 versus 2, p = 0.003), and were rehospitalized more often for infection (8 versus 0, p = 0.01). Despite severe prolonged hypogammaglobulinemia, none of the preterm infants had bacteremic illness after discharge from the nursery. This study provides normal age-group immunoglobulin values for the first 10 months of life in very small premature infants. The lack of invasive bacterial infections in this small group of preterm infants after discharge from the nursery suggests that further studies will be necessary to determine whether the hypogammaglobulinemia places these very low birth weight infants at risk for serious infection.

Prognostic value of the electroencephalogram in neonatal asphyxia

In order to determine whether an EEG early in the course of asphyxia neonatorum is of any more value than the neurological examination in predicting outcome we reviewed case histories of 38 infants with asphyxia neonatorum. The EEG background activity was valuable in predicting outcome. Normal and maturationally delayed EEGs were associated with normal outcomes while low voltage, electrocerebral inactivity and burst suppression EEGs were highly correlated with severe neurological sequelae. Epileptiform activity was not as predictive of outcome as background activity. Although initial normal neurological examinations were associated with normal developmental and neurological outcomes, moderately and severely abnormal infants had more variable courses. A single EEG done early in the course of asphyxia neonatorum is a more sensitive predictor of outcome than the neurological examination.

Hypophosphatemia and hypercalciuria in small premature infants fed human milk: evidence for inadequate dietary phosphorus.

Phosphorus and calcium balance was measured prospectively in stable premature infants (less than or equal to 1600 gm) fed human milk or a standard commercial formula. Throughout the study, the P and Ca intakes of the infants fed human milk were two to three times less than those of infants fed formula. Infants fed human milk showed low serum P and normal serum Ca concentrations, complete renal reabsorption of P, and elevated renal Ca excretion. The net effect in infants fed human milk was a 50% reduction in the P and Ca retention, compared with the formula-fed group. Despite the unfavorable P and Ca balance in the group fed human milk, the only evidence of rickets was elevated alkaline phosphatase activity. Nevertheless, based on the biochemical changes in these infants, low serum P values, and excess urinary calcium losses, we conclude that the stable small premature infant fed human milk exclusively is deficient in phosphorus and only slightly more sufficient in calcium.

Infants in Crisis

Background and description of the study the search for meaning the search for mastery the search for causes coping strategies in the hospital the search for social support mothers remembrances of newborn intensive care mothers, fathers, and couples summary and discussion.

Distortion-Product and Click-Evoked Otoacoustic Emissions of Preterm and Full-Term Infants

Abstract Full-term and preterm infants were evaluated with click-evoked and distortion product otoacoustic emissions [CEOEs and DPOEs]. The CEOEs and DWEs recorded from each individual ear were analyzed by calculating the root-mean-square levels within half-active bands. The fail criterion of the OE tests was that the half-active RMS DPOE or CEOE levels of an ear under test were below the 10th percentile of full-term newborns in two or more bands. The DPOE data were collected from 118 ears of 61 premature babies; 80 (68%] ears passed the DPOE test, 30 [25%] ears without middle ear effusions failed the test, and 8 (7%] ears with effusions also failed. The CEOE data were collected from 128 ears of 65 premature babies; 102 (80%) ears passed the CEOE test, 18 (14%) ears without middle ear effusions failed the test, and 8 (6%] ears with effusions also failed. In 23 of 80 ears (29%) that passed the DWE test and in 23 of 102 ears (23%] that passed the CEOE test, RMS OE levels of preterm infants were above the 90th percentile of full-term newborns. The analyses of the combined DPOE and CEOE data obtained from a group of 25 ears of full-term newborns and from a group of 72 ears of preterm babies showed statistically significant correlations between the DPOE and CEOE root mean-square levels in each of the half-octave bands in the 1.4 to 4 kHz region. For 42 preterm infants tested with auditory brain stem response [ABR), specificity was 86% for CEOE and 74% for DPOE. All infants who failed the ABR also failed OE tests. To the best of our knowledge, this study is the first using combined DWEs, CEOEs, and ABRs for preterm babies. It showed the feasibility of DWEs and CEOEs for this population.

EFFECT OF CALCIUM/PHOSPHORUS RATIO ON MINERAL RETENTION IN PARENTERALLY FED PREMATURE INFANTS

We hypothesized that retention of parenterally delivered calcium (Ca) and phosphorus (P) is affected by the ratio of the delivered minerals and that a 1.7:1 ratio would be optimal since this is the ratio of retention of these minerals by the fetus. Forty-one very low birth weight (VLBW) infants were randomly assigned to one of three total parenteral nutrition (TPN) solutions that were different only in their Ca:P ratios: 2:1 (76 mg/kg/day Ca and 38 mg/kg/day of P), and 1.3:1 (58 mg/kg/day Ca and 45 mg/kg/day P), and 1.3:1 (58 mg/kg/day of Ca and 45 mg/kg/day of P). Serum levels of calcium, phosphorus, and alkaline phosphatase, retentions of calcium and phosphorus and urinary cyclic AMP levels were measured after 48 h on the assigned Ca to P ratio. Calcium retentions were higher with the 2:1 and 1.7:1 ratios and phosphorus retentions were higher with the 1.3:1 and 1.7:1 ratios. The 1.7:1 ratio allowed for the highest absolute retention of both minerals and was the closest to published in utero accretion of calcium and phosphorus. The serum and urine studies demonstrated no abnormalities on any of the three ratios. Cyclic AMPs were not different among groups and were not elevated compared to previous reports suggesting that none resulted in parathyroid hormone (PTH) stimulation. We conclude that the 1.7:1 ratio is better than higher or lower ratios for delivery of calcium and phosphorus in TPN solutions at the quantities studied.

Achievement of in utero retention of calcium and phosphorus accompanied by high calcium excretion in very low birth weight infants fed a fortified formula

Calcium and phosphorus retention was evaluated in 13 very low birth weight infants who were fed an experimental formula designed to deliver quantities of calcium and phosphorus sufficient to meet the intrauterine accretion rates for these minerals. Retention of calcium and phosphorus in slight excess of these rates was achieved without any apparent difficulties for the infants. Biochemical measurements demonstrated normal serum calcium (9.8 +/- 8 mg/dL) and alkaline phosphatase (242 +/- 51.6 IU) values. However, there was evidence of high tubular reabsorption of phosphate (98.1% +/- 3.3%), hypercalciuria (7.2 +/- 3.8 mg/kg/d), and a relatively low serum phosphorus concentration (5.7 +/- 0.6 mg/dL). This biochemical picture is similar to that seen in phosphorus deficiency except for the low alkaline phosphatase activity. The latter finding, in concert with the high retention of calcium and phosphorus in these balance studies, makes such a diagnosis unlikely. We speculate that this biochemical picture is the result of an inappropriately high calcium/phosphorus ratio.

Simultaneous infusion of calcium and phosphorus in parenteral nutrition for premature infants: Use of physiologic calcium/phosphorus ratio

We hypothesized that parenteral delivery of calcium and phosphorus in a ratio of 1.7:1 would promote retention of these minerals and decrease urinary phosphorus excretion, and that delivery of increased amounts of this ratio would result in higher retentions. Serum levels and retention of calcium and phosphorus were measured as calcium intake was increased from 36 to 76 mg/kg/day in 10 mg increments and as phosphorus intake was adjusted to maintain the 1.7:1 ratio. Five different infants were studied at each of the five levels. The amounts of calcium and phosphorus retained increased steadily and at level 5 were 71.8 +/- 1.2 mg/kg/day and 40.9 +/- 1.7 mg/kg/day, respectively. Over the five levels the average percent calcium retention was 91.4 +/- 4.2 and the average percent phosphorus retention was 89.1 +/- 7.7. The provision of parenteral calcium and phosphorus in a 1.7:1 ratio resulted in a balanced retention of both minerals over the range studied. The use of this calcium/phosphorus ratio appears to be appropriate for the preterm infant receiving total parenteral nutrition.

Significance of Reactive Burst Suppression following Asphyxia in Full Term Infants

Introdutlon The burst suppression pattern in the newborn, as in the older child and adult, carries a grave prognosis. 1-3 This pattern consists of bursts of high amplitude, delta and theta activity with intermixed and often superimposed sharp waves and spikes, which last from 1-10seconds, and alternate with periods of marked background attenuation with voltage consistently below 5 microvolts. The burst suppression pattern has been noted by several authors to be nonreactive and usually does not alternate with other EEG patterns. 1,4 Burst suppression must be differentiated from the normal discontinuous pattern of sleep in term infants called trace altern ant. Trace altern ant, a discontinuous quiet sleep pattern, occurs in infants from 36weeks to 48 weeks conceptional age. Unlike burst suppression, there is often a periodicity to the bursting phase of the trace altern ant and during the period of attenuation, the background activity is higher than five microvolts. In addition, trace alternant is reactive, occurring only during certain stages of the infants sleep. 1 When the infant cycles through active or REM sleep, the EEG pattern becomes continuous, We have recently seen five term or near term asphyxiated infants who have demonstrated burst suppression during sleep, but when vigorously stimulated and awakened the infants demonstrated fairly continuous EEG activity. The purpose of this report is to review these five cases and compare outcome with fifteen asphyxiated term infants with non-reactive burst suppression.

Phosphorus Deficiency Syndrome in Very Low Birth Weight Infants

Inadequate dietary phosphorus intake is a contributing factor to the occurrence of metabolic bone disease in very low birth weight infants. This article reviews the clinical presentation and the pathophysiology of the phosphorus deficiency syndrome in premature infants. Recommendations for therapy and prevention of phosphorus deficiency are presented.