Decreased bone ultrasound velocity in large-for-gestational-age infants

BACKGROUND

Bone speed of sound is a measure of bone breakability. There are few reports on bone mineral content in large for gestational age infants; most of them in infants of diabetic mothers. There are no data on bone speed of sound in large for gestational age infants of nondiabetic mothers.

OBJECTIVE

To test the hypothesis that large for gestational age infants of nondiabetic mothers have lower bone speed of sound than appropriate for gestational age infants.

DESIGN/METHODS

Bone speed of sound was measured within the first 96 hours of life at the right tibial midshaft in 25 singleton large for gestational age infants of non diabetic mothers and compared to appropriate for gestational age controls.

RESULTS

Bone speed of sound measured in large for gestational age infants of nondiabetic mothers was lower than in controls.

CONCLUSIONS

Large for gestational age infants of nondiabetic mothers have lower bone speed of sound than controls.

Energy expenditure in human milk- versus formula-fed preterm infants

OBJECTIVE

We compared energy expenditure (EE) of preterm infants fed their mother's milk versus preterm infant formula. Study design A prospective, randomized crossover study of 13 healthy, appropriate weight for gestational age, gavage-fed, preterm infants. Before the study and according to our feeding protocol, infants uniformly received alternate feeds of human milk and formula. Each infant was randomly assigned to 24 hours of formula feeding followed by 24 hours of breast milk or the reverse. Infants were studied asleep, at the end of each 24-hour period. EE was measured by indirect calorimetry 1 hour before feeding, 20 minutes during feeding, and 1 hour after feeding in a servo-controlled convective incubator. Energy content of human milk was analyzed by bomb calorimetry.

RESULTS

EE was significantly lower in breast milk-fed infants during prefeeding (52+/-6 vs 57+/-10 kcal/kg per 24 hours) (P<.05), per feeding (55+/-6 vs 60+/-10 kcal/kg per 24 hours) (P<.05), and at the postfeeding measurement (60+/-7 vs 65+/-7 kcal/kg per 24 hours) (P=.059). After correction of the results for the actual measured energy intake, all statistical differences reached the <.05 level.

CONCLUSIONS

Preterm infants have lower EE when they are fed breast milk than when they are fed preterm infant formula.

Labor does not affect the neonatal absolute nucleated red blood cell count

We investigated whether the presence or absence of physiologic labor may affect the neonatal nucleated red blood cell (RBC) count. We compared absolute nucleated RBC counts taken at approximately 6 hours of life in term infants born by elective cesarean delivery without trial of labor ( n = 32) and in vaginally delivered infants ( n = 28). Venous blood samples were analyzed and differential cell counts were performed manually; absolute nucleated RBC were counted and expressed as an absolute number. There were no significant differences between groups in birth weight, gestational age, maternal age, gravidity, parity, maternal analgesia during labor, 1- and 5-minute Apgar scores, and infant sex. There was a significantly higher hematocrit and RBC count in the vaginally delivered group as compared with the cesarean group. The absolute nucleated RBC, corrected leukocyte and lymphocyte, and platelet counts were strikingly similar in both groups. We conclude that labor does not affect the neonatal nucleated RBC count. This finding supports the speculation that physiologic labor does not induce a fetal hypoxemia severe or prolonged enough to produce hematological evidence of increased erythropoiesis.

Neonatologists are using much less dexamethasone

Two historical cohorts (1993-1994 and 2001) of preterm infants ventilated for respiratory distress syndrome were compared. Dexamethasone administration fell from 22% to 6%. Chronic lung disease in survivors rose slightly from 13% to 17%, and mortality fell from 21% to 15% (other causes). The effect of restriction of dexamethasone use on chronic lung disease and mortality remains to be seen.

Effect of ethnicity on mortality of very low birthweight infants in Israel

BACKGROUND

Multiple demographic, genetic, and environmental factors differ between Muslim and Jewish infants in Israel.

OBJECTIVE

To evaluate whether, after adjustment for perinatal factors associated with mortality, excess mortality occurs in very low birthweight (VLBW) Muslim compared with Jewish infants.

DESIGN

The Israel National VLBW infant database includes data on 99% of all VLBW births in Israel. The study population comprised 5015 Jewish and 1549 Muslim VLBW infants of more than 23 weeks gestation, born between 1995 and 1999. The Mantel-Haenszel test was used for stratified analysis and logistic regression analysis to assess the effect of ethnic origin on mortality.

RESULTS

The death rate was significantly higher among Muslim infants (22.7% v 17.2%; crude odds ratio 1.42; 95% confidence interval 1.24 to 1.63). Excess mortality in Muslims occurred mainly in the 32-33 week (8.0% v 2.8%) and >33 week (14.7% v 4.7%) gestational age groups, and in birthweight groups of 1000-1249 g (17.6% v 9.3%) and 1250-1500 g (9.1% v 3.6%). In VLBW infants without congenital malformations, there was a significantly higher risk of mortality among Muslim infants (odds ratio 1.28; 95% confidence interval 1.04 to 1.57) compared with Jewish infants, after adjustment for gestational age, birth weight, small for gestational age, prenatal care, prenatal steroid treatment, plurality, mode of delivery, and Apgar score.

CONCLUSIONS

Excess mortality was present among Muslim VLBW infants without congenital malformations. Perinatal factors associated with increased risk of mortality were more prevalent in the Muslim VLBW population. The pattern of disparities suggests inadequate access to, or utilisation of, effective perinatal technology in the Muslim population in Israel.

Evaluation of a new thermometer for rapid axillary temperature measurement in preterm infants

Mercury-in-glass thermometers are considered the "gold-standard" for temperature measurements, but require at least 4 minutes for accuracy. Electronic thermometers sample temperature measurements over a shorter period. The objective of this study was to evaluate the accuracy and reproducibility of the Penguin (Medisim, Jerusalem, Israel) and the IVAC (San Diego, CA) Temp plus II thermometers in preterm infants. Axillary temperature was obtained in 50 thermally stable preterm infants each time with the mercury-in-glass, the IVAC, and the Penguin thermometers. Analysis of variance F-test, and linear regression analyses were used to test correlation of each electronic thermometer with the mercury-in-glass one, and the effect of body weight. Temperature measurement taken with the Penguin thermometer was significantly higher than that measured with the two other ones, p < 0.001. The differences in means and in variances were not significantly different between IVAC and mercury-in-glass, while the variance of the Penguin measurement was higher than that of the two other instruments (p < 0.001). The IVAC instrument correlated more tightly with the mercury-in-glass (r = 0.89, p < 0.001) than did the Penguin (r = 0.54, p < 0.001). There was an inverse correlation between the deviation of the Penguin measurement from the mercury-in-glass and the weight of the patient ( p < 0.08), while no significant correlation was found between the deviation of the IVAC measurement from the mercury in glass and the patient's weight (p = 0.56). Measurements of axillary temperature using the Penguin thermometer in incubated preterm infants are less accurate and less reproducible than those obtained using the IVAC or the glass thermometers.

Nucleated red blood cells in infants of mothers with asthma

OBJECTIVE

The purpose of this study was to evaluate whether the absolute nucleated red blood cell and lymphocyte count is elevated in term, appropriate-for-gestational-age infants born to women with asthma.

STUDY DESIGN

We compared absolute nucleated red blood cell counts taken during the first 12 hours of life in two groups of term, vaginally delivered, appropriate-for-gestational-age infants; one group was born to mothers with active asthma during pregnancy (n = 28 infants), and the other group was born to control mothers (n = 29 infants). Asthma severity was classified according to the National Asthma Education and Prevention Program. We excluded infants of women with diabetes mellitus, hypertension, alcohol, and tobacco or drug abuse and infants with fetal heart rate abnormalities, hemolysis, blood loss, or chromosomal anomalies.

RESULTS

There were no differences between groups in birth weight, gestational age, maternal age, gravidity, parity, maternal analgesia during labor, 1- and 5-minute Apgar scores, and infant sex. The hematocrit level, red blood cell count, absolute nucleated red blood cell count, and corrected leukocyte and lymphocyte counts were significantly higher in the asthma group than in the control group. The platelet count was not significantly different between groups. The absolute nucleated red blood cell count correlated significantly with the asthma severity score (r (2) = 28%, P <.001). Backward stepwise multiple regression that included Apgar scores and gestational age showed a significant correlation of absolute nucleated red blood cell count with the presence of asthma and its severity (P <.001).

CONCLUSION

At birth, term appropriate-for-gestational-age infants born to mothers with asthma have increased circulating absolute nucleated red blood cell and lymphocyte counts compared with control infants.

Bone ultrasound velocity curves of newly born term and preterm infants

BACKGROUND

Ultrasound velocity (speed-of-sound [SOS]) has been proposed as a non-invasive method of evaluation of bone status in infants. We hypothesized that SOS correlates with both gestational age and birth weight.

METHODS

We measured SOS within the first 96 hours of life at the right tibial midshaft location in 73 neonates ranging in gestational age from 25 to 41 weeks, and in birth weight from 825 to 3880 grams. We used the Sunlight Omnisense 7000p device (Tel Aviv, Israel). Results are expressed as meanS +/- 1 SD; statistical analyses included linear regression and computation of 95% CI regression lines; p<0.05 was considered significant.

RESULTS

There was, as hypothesized, a significant correlation between gestational age (or birth weight) and SOS. There were no significant differences between males and females. Ninety-five percent confidence intervals were established.

CONCLUSIONS

These data may be used as reference ranges for further studies.

Nucleated red blood cells in polycythemic infants

OBJECTIVE

This study was undertaken to evaluate whether the absolute nucleated red blood cell (RBC) count is elevated in term, appropriate-for-gestational-age (AGA) polycythemic infants.

STUDY DESIGN

We compared absolute nucleated RBC counts taken during the first 12 hours of life in term, AGA infants with neonatal polycythemia (n = 29), and in control, nonpolycythemic infants (n = 37). We excluded infants of women with diabetes, hypertension, and alcohol, tobacco, or drug abuse, and those with fetal heart rate abnormalities or low Apgar scores, hemolysis, blood loss, or chromosomal anomalies.

RESULTS

There were no differences between groups in birth weight, gestational age, or other demographic or perinatal factors. The hematocrit, RBC count, and absolute nucleated RBC counts were significantly higher and the platelet counts significantly lower in the polycythemic group. Regression analysis that included Apgar scores and gestational age showed a significant correlation of absolute nucleated RBC count with the polycythemia status only (P =.017).

CONCLUSION

At birth, term AGA polycythemic infants have increased indices of active erythropoiesis. We speculate that this finding is suggestive of subtle fetal hypoxemia.

Effect of albumin on neonatal serum ionized magnesium in vitro

BACKGROUND

Human serum albumin (HAS) is used to treat hypoproteinaemia in neonates and as a volume expander. The aim of this study was to quantify the decrease in serum concentration of ionized magnesium ([Mg2+]) when human serum albumin is added to neonatal serum in vitro.

METHODS

Human serum albumin was added to 20 cord serum samples of term infants to reach incremental concentrations of 0 to 20.0 g/l and [Mg2+] were measured.

RESULTS

Serum [Mg2+] decreased significantly with the addition of serum albumin. At incremental serum albumin concentration of 10 to 20 g/l, which is within the range of the desired aim in the treatment of hypoalbuminaemia, the magnitude of the decrease in serum [Mg2+] was approximately 0.041 to 0.052 mmol/l (10 to 13 per cent) from the average baseline value.

CONCLUSION

The addition of albumin causes a decrease in [Mg2+]. From this in vitro study we speculate that fast infusion of albumin in human neonates may potentially cause a clinically significant decrease in serum [Mg2+].

Neonatal nucleated red blood cells in G6PD deficiency

The objective of this study is to study the absolute number of nucleated red blood cells (RBC) at birth, an index of active fetal erythropoiesis, in infants with G6PD deficiency and in controls. We tested the hypothesis that hematocrit and hemoglobin would be lower, and absolute nucleated RBC counts higher, in the G6PD deficient and that these changes would be more prominent in infants exposed passively to fava bean through maternal diet. Thirty-two term infants with G6PD deficiency were compared with 30 term controls. Complete blood counts with manual differential counts were obtained within 12 hours of life. Absolute nucleated RBC and corrected leukocyte counts were computed from the Coulter results and the differential count. G6PD deficient patients did not differ from controls in terms of gestational age, birth weight, or Apgar scores or in any of the hematologic parameters studied, whether or not the mother reported fava beans consumption in the days prior to delivery. Although intrauterine hemolysis is possible in G6PD deficient fetuses exposed passively to fava beans, our study supports that such events must be very rare.

Massage therapy by mothers and trained professionals enhances weight gain in preterm infants

BACKGROUND

The method of "massage therapy" has consistently shown increased weight gain in preterm infants. The weight gain was apparent during massages administered by professionals.

AIMS

To replicate the results of increased weight gain in the course of "massage therapy" in preterm infants, and utilize a new, cost-effective application of this method by comparing maternal to nonmaternal administration of the therapy.

STUDY DESIGN

Random cluster design.

SUBJECTS

The study comprised 57 healthy, preterm infants assigned to three groups: two treatment groups--one in which the mothers performed the massage, and the other in which a professional female figure unrelated to the infant administered the treatment. Both these groups were compared to a control group.

RESULTS

Over the 10-day study period, the two treatment groups gained significantly more weight compared to the control group (291.3 and 311.3 vs. 225.5 g, respectively). Calorie intake/kg did not differ between groups.

CONCLUSIONS

Mothers are able to achieve the same effect size as that of trained professionals, allowing cost-effective application of the treatment within the neonatal intensive care unit.

Effect of head support on oxygen saturation in preterm infants restrained in a car seat

We prospectively tested the hypothesis that prevention of lateral movement of the head, using a specially designed head support apparatus, would prevent oxygen desaturation in preterm infants restrained in car seats. Preterm infants reaching 34 to 35 weeks' gestation were studied at the week of discharge in 3 different conditions for 20 minutes each time: supine decubitus, sitting position in a newborn car seat, and sitting position in the car seat equipped with an apparatus that supports the head, while monitored by pulse oxymetry. Data are expressed as percent of time over each period during which the oxygen saturation was below 90, 92, 94, or 96%. Statistical analysis was by analysis of variance (ANOVA) followed by paired Student t-test for differences of means. There were no significant differences among groups in percent of time with oxygen saturation below 96, 94, 92, or 90%. Oxygenation is not improved in relatively healthy preterm infants placed in a car seat when their head is supported to prevent lateral movements by a special apparatus.

A reappraisal of neonatal blood chemistry reference ranges using the Nova M electrodes

The objective of this study is to establish new reference ranges for whole blood electrolytes, gases, and selected chemistries in normal healthy newborn infants obtained from cord blood and at 2-4 hours of life based on modern analytic techniques. Healthy appropriate-for-gestational age (AGA), term infants were studied. Whole venous cord blood and blood drawn at 2-4 hours of life were analyzed for gases, sodium, potassium, chloride, ionized calcium, ionized magnesium, hemoglobin, and hematocrit. Concentrations for blood glucose and blood urea nitrogen were close to older published concentrations. Na(+), K(+), and Cl(-) were significantly different and had much narrower normal margins. New norms are included for blood gases, lactate, iCa, and iMg. We offer a range of values for often-measured blood chemistries in term, healthy infants, using modern laboratory methods. These values could serve as more up-to-date references compared with older values found in major textbooks of Neonatology.

Precision of a new thermometer for rapid rectal temperature measurement in neonates

The objective of this article is to evaluate the accuracy and reproducibility of a Penguin electronic thermometer compared with a mercury-in-glass thermometer for rectal thermometry in newborns. The mercury-in-glass thermometer is considered the "gold-standard" for rectal thermometry. Unfortunately, accurate measurement with a mercury-in-glass thermometer requires at least 4 minutes. Rectal temperature was obtained in 224 term and near-term infants using a mercury-in-glass and a Penguin thermometers. Paired t-test was used to test the difference between the means, and F-test was used to test the difference between the variances of the two instruments. One hundred and sixty-one of the temperature measurements (72%) taken with the Penguin thermometer were within +/-0.2 degrees C and 208 (93%) within +/-0.5 degrees C from the measurements made with the mercury-in-glass thermometer. The differences in means and in variances were not significantly different between the instruments. The Penguin thermometer is an accurate and reproducible tool for measuring rectal temperature in term and near-term infants compared with the mercury-in-glass thermometer.

Double catheter technique for misdirected umbilical vein catheter

We studied the success rate of the double catheter technique during umbilical vein catheter placement in 42 patients with a misdirected umbilical vein catheter. The misdirected catheter was left in place, and an additional catheter was inserted. X-ray films confirmed that successful placement was achieved in 50% of infants without significant adverse effects.

Prognostic significance of hyperechogenic lesions in the basal ganglia and thalamus in neonates

Neonatal cranial ultrasonography at times reveals hyperechogenic lesions in the basal ganglia and thalamus. These lesions have been attributed to a wide variety of pathologic states, among them toxoplasmosis, rubella, cytomegalovirus, and herpes simplex (TORCH) infections, chromosomal abnormalities, and asphyxia. The clinical significance in terms of the neurodevelopmental outcome of this radiologic abnormality is unknown. We performed a developmental evaluation on 16 children aged 2 to 6 years in whom neonatal cranial ultrasonography had demonstrated hyperechogenic lesions in the basal ganglia or thalamus and had no other neurodevelopmental risk factors. There was no significant difference between the average Developmental Quotient of the target population and the normal population in regard to developmental status. We conclude that in our population, an isolated finding of hyperechogenic lesions in the basal ganglia is probably not a predictor of poor neurodevelopmental outcome.

A comparison of intakes of breast-fed and bottle-fed infants during the first two days of life

OBJECTIVE

In the first days of life, breast-fed infants consume minimal amounts of milk; this may be explained by substrate limitation (limited milk output) and/or by self-limitation (through low appetite and/or suck-swallow competency). The spontaneous milk intake of unrestricted formula-fed infants has not been studied to date. We compared the spontaneous formula intake of unrestricted formula-fed infants to that of breast-fed infants over the first 48 hours of life. We hypothesized that 1) spontaneous formula intake of unrestricted infants is much higher than that of breast-fed infants and 2) spontaneous formula intake correlates positively with gestational age or birthweight.

METHODS

We studied 43 healthy, term infants. By maternal choice, 15 infants were exclusively breast-fed and 28 were formula-fed ad libitum every four hours. Breast-fed infants were weighed before and one hour after initiation of feeding, and intake was calculated from the difference between the measurements and corrected individually for the infant's normal postnatal decrease in body weight. Bottles offered to formula-fed infants contained 60 cc, and the remainder was carefully measured. Intakes were expressed as cc/kg/d, and weight changes as % of birthweight. Statistical methods included Student's t tests and stepwise regression analysis.

RESULTS

Breast feeding on Day I was 9.6 +/- 10.3 (mean +/- SD) vs. 18.5 +/- 9.6 cc/kg/d in formula-fed infants (p=0.011); on Day 2 it was 13.0 +/- 11.3 vs. 42.2 +/- 14.2 cc/kg/d (p<0.001). Breast-fed infants lost significantly more weight on Day 2 (p=0.015). In multiple regression, when the dependent variable was the second-day intake, the significant independent variables were group (higher intake in the formula-fed group), weight loss (the higher the weight loss, the lower the intake), and first-day intake (the higher the first-day intake, the higher the second-day intake).

CONCLUSION

Newborn infants offered formula ad libitum every four hours consumed much larger amounts than breast-fed infants fed according to the same schedule. In addition, weight loss was more marked in breast-fed infants on Day 2 of life.

Nucleated red blood cells in meconium aspiration syndrome

OBJECTIVE

To evaluate whether the absolute nucleated red blood cell (RBC) count is higher in infants who had meconium aspiration with respiratory symptoms compared with infants with asymptomatic meconium aspiration and controls.

METHODS

We compared the absolute nucleated RBC counts during the first 12 hours of life in three groups of term, vaginally delivered infants, including those who had meconium aspiration with respiratory symptoms (n = 11), asymptomatic meconium aspiration (n = 45), and control healthy infants (n = 32). We excluded infants of women with diabetes in pregnancy; hypertension; alcohol, tobacco, or drug abuse; and those with hemolysis, blood loss, or chromosomal anomalies.

RESULTS

There were no significant differences among groups in gestational age; gravidity; parity; maternal analgesia; lymphocyte, platelet, and granulocyte counts; and hematocrit. The median nucleated RBC count was significantly higher in the meconium aspiration group with respiratory symptoms (0.007 x 10(9)/L) than the asymptomatic meconium aspiration group (0.004 x 10(9)/L) or controls (0.003 x 10(9)/L).

CONCLUSION

At birth, infants with meconium aspiration syndrome had higher absolute nucleated RBC counts compared with infants with asymptomatic meconium aspiration and normal infants.

Continuous measurement of core body temperature in preterm infants

We tested a transcutaneous core temperature sensor using a method that relies on the principle of zero heat flow. We tested the hypothesis that transcutaneous and rectal temperatures would track within 0.3 degrees C of each other for >90% of the time. A thermistor was placed between the infant's abdomen or back and the incubator's or radiant warmer's mattress, or within the axilla, attached to the skin with a foam adhesive disk insulator. Thirty preterm infants were either placed on their abdomens or backs in a convective incubator or under a radiant warmer, and continuous transcutaneous and rectal temperatures were measured for 1 hour. There were no significant differences between abdominal and core temperatures or between axillary and core temperatures measured in double-walled convective incubators or in radiant warmers. The rectal-abdominal temperature difference was significantly less than the rectal-axillary difference (p < 0.02) in convective incubators, but not when the infant was placed prone under radiant warmers (p = 0.27). Transcutaneous thermometry is reliable for monitoring core body temperature as indicated by rectal temperature in stable preterm infants in a convective incubator.

Maturation of thermal capabilities in preterm infants

Very low-birth-weight infants (VLBW) may initially require environmental temperatures higher than skin temperature. We examined the correlation between gestational age, birth weight, and the time to reach skin-air temperature equilibration (TTE) in VLBW infants. We also examined the effect of antenatal steroids on TTE in infants with birth weight < 1000 g. There is a significant exponential correlation between TTE and birth weight or gestational age (p < 0.05). There was no significant change in TTE in infants who were treated antenatally with steroids, as compared with infants who were not treated. Multiple regression analysis with TTE as the dependent variable and birth weight or gestational age, race, betamethasone treatment, and gender as the independent variables showed a significant correlation between gestational age and TTE (p = 0.04). We conclude that thermal capabilities are exponentially correlated with gestational age or birth weight.