Carlos Fustiñana

Early hypophosphatemia in preterm infants receiving aggressive parenteral nutrition.

Objective:To report the prevalence of hypophosphatemia during the first week of life in preterm infants receiving aggressive parenteral nutrition and to analyze population variables associated with severe hypophosphatemia.Study design:A retrospective cohort of 61 neonates below 1250 g birth weight consecutively born at Hospital Italiano de Buenos Aires exposed to high caloric and protein intake from the first day of birth. Primary outcome was hypophosphatemia (phosphate <4 mg dl−1). A one-sample mean comparison test was used to compare our sample with a hypothesized population mean.Results:The prevalence of hypophosphatemia was 91% (95% confidence interval (CI) 82 to 97%). The mean phosphatemia value was 2.52 mg dl−1 (95% CI 2.18 to 2.86), significantly different from the hypothesized population mean (P<0.001). Patients with severe hypophosphatemia (<2 mg dl−1) were smaller. They presented with sepsis more frequently and received more vasoactive drugs and mechanical ventilation.Conclusion:The prevalence of hypophosphatemia in this group of preterm infants is high. The potential association with adverse clinical outcomes deserves further research.

CONTROLLED TRIAL OF PRENATAL BETAMETHASONE (B) PLUS TRH FOR PREVENTION OF RESPIRATORY DISTRESS SYNDROME (RSD) IN PRETERM INFANTS

A double- blind, randomized trial was carried out, to evaluate the effects of prenatal administration of B and TRH on the incidence and severity of RDS. 57 premature infants (26-31 weeks of gestation) born from 52 mothers treated for 10 days prior to labor, were included. The study group (G1) (n=26) received B: 12mg IM q12 h plus TRH 200 ug IV q12 h. The control group (n=31) (G2) received an equal dose of B plus placebo. Incidence of RDS was 27% and 29% in G1 and G2, respectively. Significant differences were found in the duration of treatment with O2; [xmacr ] 21 vs 108 h in G1 and G2, respectively (p= .004) and in the duration of IPPV [xmacr ] 6.3 days in G2 vs 13.9 in G1 (p<0.05). Among there surviving beyond 28 days of life no infants in G1 received Fi02 > .21, while 6 (25%) in G2 required this treatment for a longer period (p= .02). No infants in G1 and 5 in G2 (21%) developed Bronchopulmonary displasia (BPD) (p= .02), Prenatal treatment with B plus TRH may be more efficient than B alone in reducing O2 requirements and the duration of oxygen therapy and mechanical ventilation. This therapy may diminish the incidence of BPD.

A New Bottle Design Decreases Hypoxemic Episodes during Feeding in Preterm Infants

Oxygen saturation is lower during bottle feeding than during breastfeeding in preterm infants. Our objective was to compare two different bottle systems in healthy preterm infants before discharge in terms of SpO2 and oral feeding efficiency (rate of milk intake). Infants without supplement oxygen needs were evaluated twice on the same day during two consecutive feeds, by the same nurse. Infants served as their own controls for comparison of two systems of bottles, the order of which was randomized. The new bottles nipple design mimics moms breast in shape and feel, and the bottle vents to air when the child sucks on the nipple. The other system was the hospitals standard plastic bottle with silicone nipple. The rate of milk intake was calculated as the total volume transferred minus volume lost divided by time of feeding, mL/min. Thirty-four infants (BW: 1, 163 ± 479.1 g) were studied at 35.4 ± 1.3 weeks after-conception. SpO2 was significantly higher in infants fed with the new bottle design. Milk intake rate was significantly higher with the new bottle than with the standard bottle design. The new bottle design improves oral feeding performance in preterm infants near to discharge when compared to that of a standard bottle.

Open lung strategy in a lamb model of respiratory distress syndrome.

We tested the hypothesis that an open lung strategy with recruitment maneuvers will improve oxygenation and decrease lung injury in comparison with a permissive hypercapnia strategy in preterm lambs. Preterm lambs born by operative delivery at 131 ± 1 days of gestational age (term = 150 days) were randomized to an open lung group (OLG, n = 5) or a permissive hypercapnia group (PHG, n = 4). In the OLG, ramp recruitment maneuvers were performed by increasing and then decreasing peak inspiratory pressure and positive end-expiratory pressure (adjusting for expiratory tidal volume [V(T)] 6 to 8 mL/kg). In the PHG, lambs received ventilation with V(T) of 6 to 8 mL/kg, adapting pressures and respiratory rate according to arterial blood gases results. Fraction of inspired oxygen was adjusted for oxygen saturation 88 to 93%. Lambs were ventilated for 6 hours. Lung pathology was assessed by masked examiners. There were no significant differences for arterial to alveolar oxygen tension ratio, partial pressure of arterial carbon dioxide, blood pressure, compliance, resistance, and other variables between groups. Gas leaks were noted in four of five lambs in the OLG and one of four in the PHG (relative risk 3.2; 95% confidence interval 0.5 to 18). By histological examination, lung areas were overdistended (49% in the OLG, 37% in the PHG). Open lung ventilation following ramp recruitment maneuvers did not offer advantages and might increase lung injury compared with a permissive hypercapnia strategy in preterm lambs with lung immaturity.

Efectos de la administración de glucocorticoides prenatales en el desarrollo de la enterocolitis necrosante en neonatos de rata wistar

INTRODUCTION Necrotizing enterocolitis (NEC) is a frequent problem in preterm infants. Prenatal treatment with steroids proved to be effective for lung maturation and it is thought to have a protective effect on the immature bowel. OBJECTIVES To study the effects of prenatal treatment with steroids at the onset, clinical course and histological pattern of NEC in an animal model. METHODS Pregnant rats received treatment with intraperitoneal hydrocortisone (5 mg/kg) 24 and 48 hrs prior to the expected date of delivery (group S). Control pregnant rats were injected with normal saline, at the same timing (group P). After term delivery by cesarean section, both groups were kept in identical conditions in a neonatal incubator at 35ºC, away from their mothers to prevent any exposure to breast milk. Pups were fed every three hours with neonatal formula via an orogastric tube. To further increase the susceptibility to NEC, pups were exposed to hypoxia followed by hypothermia three times a day for 72 hrs (H-H) or until development of clinical signs of NEC. At that point, each animal was anesthetized and euthanized. The intestine was fixed for histological analysis. Those animals which died before 72 hours were excluded to prevent false positive results in the histopathological exam. RESULTS The clinical signs of NEC include oral intolerance, gastric residuals, respiratory distress, abdominal distension, wall erythema and hematochezia; 60% of animals in group P (n= 16) presented with at least one clinical sign, vs. 40% of pups in group S (n= 15). The onset of clinical signs and clinical course in group S was more benign than in group P. Mortality rate was 40% for pups in group P vs. 20% for group S (NS). Histological analysis indicated that 80% of the animals from group P showed signs of NEC, of which 50% reached grade 3-4 (maximum score of damage), whereas only 40% of the animals in group S presented with signs of NEC (p<0.05), all were of grade 0-1 (minimum histological damage). CONCLUSIONS Prenatal treatment with steroids was effective for amelioration of the onset and clinical presentation in this model of experimental NEC.

Efectos del destete temprano sobre el comportamiento adulto en un modelo animal

Early weaning (EW) has proven to be a factor that decreases the animals organic resistance against adverse conditions. Climbing in the forced swimming test (FST) is the active behavior that expresses the will of the rat to escape the stressful situation. A possible association between these two stress factors (EW and FST) has not yet been reported as a plausible model for the study of stress and depression. Under the working hypothesis that EW has possible adult behavioral correlates when associated with the FST, our objective was to analyze the levels of alteration in the active behaviors among groups. 20 Wistar rats (4 month old), were divided into two groups, the early weaned group (G1) and a control group (G2). The unit of analysis (tip), was defined as the number of intended escapes the animal performs in five minutes. We have found the differences stated by our hypothesis, comparing the frequency of scale or escape (tips), from a group with EW to a control group (15.8 +/- 4.15 vs. 21.4 +/- 4.14, p< 0.05). In turn, we found that, among females, the difference was significantly wider. The present study could elucidate under experimental conditions the effect that in adult behavior induces an alteration in the more primary bonds.

P08.12: Fetal and neonatal clinical evolution of isolated congenital heart disease and associated with major extracardiac malformations or genetic syndromes

in imaging protocols. The detection rates in in-born babies was considerably higher than in out-born babies. There was close correlation between antenatal and post-natal findings. Conclusions: We have demonstrated an improvement in overall detection rates over a 10 year period, however rates are still not close to 100%. The next step is to implement an educational plan for our rural and regional hospitals and hope to then demonstrate a further improvement in detection levels, in order to reduce the incidence or out-born babies.

GROWTH VELOCITY IN VERY LOW BIRTH WEIGHT INFANTS. ARE THE REFERENCE GROWTH CHARTS APPROPRIATE

Growth of very low birth weight infants (VLBWI) is usually assesed by Standard Reference Curves (SRC). These chars are composed by prenatal growth curves up to term (cross sectional studies) followed by post natal longitudinal growth charts of fullterm healthy babies. Our purpose was to compare the growth velocity of SRC with the lenght, weight and head circumference growth velocity of a population of 35 VLBWI with low neonatal morbidity and adequate weight for gestational age, who were followed up for one year of corrected age. Birth weight of this population was ([xmacr ] ± SD): 1290 ± 150, lenght: 38.3 ± 2.8, head circumference: 26.3 ± 1.3 and gestational age: 30 ± 1.3 weeks. The accelerated growth period of the three parameters showed a quadratic regression (parabola), with its acme retarded 4 weeks compared to SRC for weight and 5 weeks for head circumference and body lenght, its magnitude being significantly greater (p < 0.01) in the SRC (for weight and lenght) than in the VLBWI (350g ± 80 vs 270 ± 90 and 1.3 ± 0.2 vs 1.02 ± 0.1). Total accumulated growth at one year was similar in both curves.Increased growth velocity in VLBWI lasted until six months of corrected age and not up to full term only as in SRC. Our results suggest that for clinical assessement of rapid growth period in premature infants, SRC do not adequately reflect changes in growth velocity during this critical period.

AFFECTING FACTORS TO CATCH UP GROWTH IN VERY LOW BIRTH WEIGHT (VLBW) INFANTS DETECTED THROUGH A MATHEMATICAL MODEL

Rate of posnatal “catch-up” growth was examined applying a mathematical model, which allowed to evaluate catch up growth in length(L), weight(W) and cephalic circumferences (CC). In a group of 120 VLBW infants bom from 1980-86, 82 were selected for the study meeting the following criteria: no intrauterine growth retardation, prenatal infection and major malformation. Mean birth weight(BW) and gestational age(GA) were 1217±193 and 29.1±1.6 weeks, respectively. Apgar scores at 1st and 5th min. were 6.9 ± 3 and 8.8±2.0. The independent variables were BW, GA, socioeco-nomical status, perinatal and neonatal morbidity, and age taken at the time when calories intake reached 100cal/Kg/day and BW had been recovered. The dependent variables were catch up growth in W, L and CC. The stepwise regression analysis showed variables which correlated with catch up growth were: neonatal morbility, age which birth weight was recovered and age at the time to reach 100cal/ftg/day. They were also dependent among themselves. The regression coefficient were r = .72 (p<.0001), r = .79 (p<.0001), r = .63 (p<.01) for catch up growth for W, L and CC, respectively. The data showed that failure to catch up growth was related to the poor caloric intake received by this group secondary to morbidity. Better management of nutrition may improve catch up growth. This analysis allows earlier identification of infants with delayed catch up growth and the responsible variables. The three above variables may be used to predict tlie risk of no catch up growth in W and L in VLBW infants.