Evaluación posalta del crecimiento en prematuros: implicaciones de adoptar las curvas OMS / Post discharge growth assessment in preterm infants: implications of adopting the WHO standards

Introducción. Los estándares para evaluar el crecimiento en los prematuros se han utilizado como referencia desde el año 1986. La introducción de las curvas OMS en la Argentina podría incrementar la detección de los niños con crecimiento subóptimo. Objetivo. Comparar la proporción de retraso del crecimiento en peso, longitud corporal y perímetro cefálico en prematuros con peso al nacer menor de 1500 g (RNMBPN) evaluados por las curvas OMS y las curvas SAP. Pacientes y métodos. Estudio de cohorte en RNMBPN. Se incluyeron las mediciones de peso, longitud corporal y perímetro cefálico, realizadas a las 40, 53, 66, 79 y 92 semanas posmenstruales (± 1 semana). Se registró como variable independiente el sexo para ambas curvas (OMS y SAP). Se analizaron las medias del puntaje Z para ambas curvas mediante la prueba de Student y la diferencia de proporciones mediante la prueba de la χ² (OR; IC 95%). Resultados. Ingresaron 204 niños. Las variables antropométricas al nacer divididas por sexo no mostraron diferencias. El peso y la longitud mostraron una apreciación mayor del crecimiento por las curvas SAP vs. OMS, más en los varones que en las mujeres, y se atenuaron al año de edad. La estatura evaluada por OMS presentó retraso en ambos sexos. La circunferencia craneal no arrojó diferencias. Se encontró una mayor proporción de pacientes con peso por debajo de 2 desviaciones estándar a los 3 meses de edad según OMS (p < 0,01; OR 0,36; IC 95% 0,15 a 0,78), no así para la longitud y el perímetro cefálico. Conclusiones. Este estudio permite sugerir que el cambio de estándar no implicaría una modificación significativa a nuestras prácticas de seguimiento durante el primer año de edad.

Introduction. The WHO standards have been used as a gold standard for growth assessment in preterm infants since 1986. The introduction of the WHO standards in Argentina could improve detection of sub-optimal growth. Objective. To compare the proportion of growth retardation in terms of weight, body height and head circumference in preterm infants with a birth weight less than 1500 g (VLBW) assessed according to the WHO standards and the Sociedad Argentina de Pediatría (SAP) standards. Population and methods. Cohort study in VLBW newborn infants. Measurements included were weight, height and head circumferences measured at 40, 53, 66, 79 and 92 postmenstrual weeks (±1 week). Sex was recorded as an independent outcome measure for both standards (WHO and SAP). Mean Z scores were analyzed for both standards using Student's test, and the difference of proportions was assessed using the c2 test (OR; 95% CI). Results. Two hundred and four infants were included. No differences were observed in anthropometric outcome measures at birth by sex. A greater growth was seen in terms of weight and height as per the SAP standards compared to the WHO standards, which was more marked in male infants than female infants, and which diminished around their first year of life. Growth retardation in terms of height was observed in both males and females assessed with the WHO standards. No differences were observed in head circumference. A higher proportion of patients with a weight below 2 standard deviations at 3 months old was found as per the WHO (p < 0.01; OR: 0.36; 95% CI: 0.150.78), but that was not the case with height and head circumference. Conclusions. This study allows to suggest that changing the standards does not imply a significant modification in our follow-up practice over the first year of life of an infant.

Evaluación posalta del crecimiento en prematuros: implicaciones de adoptar las curvas OMS / Post discharge growth assessment in preterm infants: implications of adopting the WHO standards

Introducción. Los estándares para evaluar el crecimiento en los prematuros se han utilizado como referencia desde el año 1986. La introducción de las curvas OMS en la Argentina podría incrementar la detección de los niños con crecimiento subóptimo. Objetivo. Comparar la proporción de retraso del crecimiento en peso, longitud corporal y perímetro cefálico en prematuros con peso al nacer menor de 1500 g (RNMBPN) evaluados por las curvas OMS y las curvas SAP. Pacientes y métodos. Estudio de cohorte en RNMBPN. Se incluyeron las mediciones de peso, longitud corporal y perímetro cefálico, realizadas a las 40, 53, 66, 79 y 92 semanas posmenstruales (± 1 semana). Se registró como variable independiente el sexo para ambas curvas (OMS y SAP). Se analizaron las medias del puntaje Z para ambas curvas mediante la prueba de Student y la diferencia de proporciones mediante la prueba de la χ² (OR; IC 95%). Resultados. Ingresaron 204 niños. Las variables antropométricas al nacer divididas por sexo no mostraron diferencias. El peso y la longitud mostraron una apreciación mayor del crecimiento por las curvas SAP vs. OMS, más en los varones que en las mujeres, y se atenuaron al año de edad. La estatura evaluada por OMS presentó retraso en ambos sexos. La circunferencia craneal no arrojó diferencias. Se encontró una mayor proporción de pacientes con peso por debajo de 2 desviaciones estándar a los 3 meses de edad según OMS (p < 0,01; OR 0,36; IC 95% 0,15 a 0,78), no así para la longitud y el perímetro cefálico. Conclusiones. Este estudio permite sugerir que el cambio de estándar no implicaría una modificación significativa a nuestras prácticas de seguimiento durante el primer año de edad.(AU)

Introduction. The WHO standards have been used as a gold standard for growth assessment in preterm infants since 1986. The introduction of the WHO standards in Argentina could improve detection of sub-optimal growth. Objective. To compare the proportion of growth retardation in terms of weight, body height and head circumference in preterm infants with a birth weight less than 1500 g (VLBW) assessed according to the WHO standards and the Sociedad Argentina de Pediatría (SAP) standards. Population and methods. Cohort study in VLBW newborn infants. Measurements included were weight, height and head circumferences measured at 40, 53, 66, 79 and 92 postmenstrual weeks (±1 week). Sex was recorded as an independent outcome measure for both standards (WHO and SAP). Mean Z scores were analyzed for both standards using Students test, and the difference of proportions was assessed using the c2 test (OR; 95% CI). Results. Two hundred and four infants were included. No differences were observed in anthropometric outcome measures at birth by sex. A greater growth was seen in terms of weight and height as per the SAP standards compared to the WHO standards, which was more marked in male infants than female infants, and which diminished around their first year of life. Growth retardation in terms of height was observed in both males and females assessed with the WHO standards. No differences were observed in head circumference. A higher proportion of patients with a weight below 2 standard deviations at 3 months old was found as per the WHO (p < 0.01; OR: 0.36; 95% CI: 0.150.78), but that was not the case with height and head circumference. Conclusions. This study allows to suggest that changing the standards does not imply a significant modification in our follow-up practice over the first year of life of an infant.(AU)

Post discharge growth assessment in preterm infants: implications of adopting the WHO standards.

INTRODUCTION: The WHO standards have been used as a gold standard for growth assessment in preterm infants since 1986. The introduction of the WHO standards in Argentina could improve detection of sub-optimal growth. OBJECTIVE: To compare the proportion of growth retardation in terms of weight, body height and head circumference in preterm infants with a birth weight less than 1500 g (VLBW) assessed according to the WHO standards and the Sociedad Argentina de Pediatría (SAP) standards. POPULATION AND METHODS: Cohort study in VLBW newborn infants. Measurements included were weight, height and head circumferences measured at 40, 53, 66, 79 and 92 postmenstrual weeks (±1 week). Sex was recorded as an independent outcome measure for both standards (WHO and SAP). Mean Z scores were analyzed for both standards using Student's test, and the difference of proportions was assessed using the c2 test (OR; 95% CI). RESULTS: Two hundred and four infants were included. No differences were observed in anthropometric outcome measures at birth by sex. A greater growth was seen in terms of weight and height as per the SAP standards compared to the WHO standards, which was more marked in male infants than female infants, and which diminished around their first year of life. Growth retardation in terms of height was observed in both males and females assessed with the WHO standards. No differences were observed in head circumference. A higher proportion of patients with a weight below 2 standard deviations at 3 months old was found as per the WHO (p < 0.01; OR: 0.36; 95% CI: 0.150.78), but that was not the case with height and head circumference. CONCLUSIONS: This study allows to suggest that changing the standards does not imply a significant modification in our follow-up practice over the first year of life of an infant.

Post discharge growth assessment in preterm infants: implications of adopting the WHO standards. / Post discharge growth assessment in preterm infants: implications of adopting the WHO standards.

INTRODUCTION: The WHO standards have been used as a gold standard for growth assessment in preterm infants since 1986. The introduction of the WHO standards in Argentina could improve detection of sub-optimal growth. OBJECTIVE: To compare the proportion of growth retardation in terms of weight, body height and head circumference in preterm infants with a birth weight less than 1500 g (VLBW) assessed according to the WHO standards and the Sociedad Argentina de Pediatría (SAP) standards. POPULATION AND METHODS: Cohort study in VLBW newborn infants. Measurements included were weight, height and head circumferences measured at 40, 53, 66, 79 and 92 postmenstrual weeks (±1 week). Sex was recorded as an independent outcome measure for both standards (WHO and SAP). Mean Z scores were analyzed for both standards using Students test, and the difference of proportions was assessed using the c2 test (OR; 95

CI). RESULTS: Two hundred and four infants were included. No differences were observed in anthropometric outcome measures at birth by sex. A greater growth was seen in terms of weight and height as per the SAP standards compared to the WHO standards, which was more marked in male infants than female infants, and which diminished around their first year of life. Growth retardation in terms of height was observed in both males and females assessed with the WHO standards. No differences were observed in head circumference. A higher proportion of patients with a weight below 2 standard deviations at 3 months old was found as per the WHO (p < 0.01; OR: 0.36; 95

CI: 0.150.78), but that was not the case with height and head circumference. CONCLUSIONS: This study allows to suggest that changing the standards does not imply a significant modification in our follow-up practice over the first year of life of an infant.

Fetal and neonatal mortality in patients with isolated congenital heart diseases and heart conditions associated with extracardiac abnormalities.

Congenital malformations are a known cause of intrauterine death; of them, congenital heart diseases (CHDs) are accountable for the highest fetal and neonatal mortality rates. They are strongly associated with other extracardiac malformations and an early fetal mortality. Two hundred and twenty fves cases of CHDs are presented. Of them, 155 were isolated CHDs (group A) and 70 were associated with extracardiac malformations, chromosomal disorders, or genetic syndromes (group B). The overall mortality in group B was higher than that observed in group A (p <0.01). Prenatal mortality was similar in both groups: A: 8.4% (13 out of 155); B: 15.7% (11 out of 70). Postnatal mortality was A: 16.8% (26 out of 155) (p <0.01), OR: 0.52 (95% CI: 0.16-1.7); B: 32.9% (23 out of 70) (p <0.01), OR: 0.41 (95% CI: 0.20-0.83). Heart diseases associated with extracardiac abnormalities had a higher mortality rate than isolated congenital heart diseases in the period up to 60 weeks of postmenstrual age (140 days post-term). No differences were observed between both groups of patients in terms of prenatal mortality.

Fetal and neonatal mortality in patients with isolated congenital heart diseases and heart conditions associated with extracardiac abnormalities / Mortalidad fetal y neonatal en pacientes con cardiopatías congénitas aisladas y asociadas a anomalías extracardíacas

Congenital malformations are a known cause of intrauterine death; of them, congenital heart diseases (CHDs) are accountable for the highest fetal and neonatal mortality rates. They are strongly associated with other extracardiac malformations and an early fetal mortality. Two hundred and twenty fves cases of CHDs are presented. Of them, 155 were isolated CHDs (group A) and 70 were associated with extracardiac malformations, chromosomal disorders, or genetic syndromes (group B). The overall mortality in group B was higher than that observed in group A (p <0.01). Prenatal mortality was similar in both groups: A: 8.4% (13 out of 155); B: 15.7% (11 out of 70). Postnatal mortality was A: 16.8% (26 out of 155) (p <0.01), OR: 0.52 (95% CI: 0.16-1.7); B: 32.9% (23 out of 70) (p <0.01), OR: 0.41 (95% CI: 0.20-0.83). Heart diseases associated with extracardiac abnormalities had a higher mortality rate than isolated congenital heart diseases in the period up to 60 weeks of postmenstrual age (140 days post-term). No differences were observed between both groups of patients in terms of prenatal mortality.(AU)

Las malformaciones congénitas son una causa reconocida de muerte intrauterina. De ellas, las cardiopatías congénitas (CC) ocasionan la mayor mortalidad fetal y neonatal. La asociación con otras malformaciones extracardíacas es elevada y se acompaña de una mortalidad fetal temprana. Se presentan 225 casos de CC. En 155 casos fueron CC aisladas (grupo A) y en 70 se asociaron con malformaciones extracardíacas, cromoso-mopatías o síndromes genéticos (grupo B). La mortalidad global en el grupo B fue mayor con respecto al grupo A (p < 0,01). La mortalidad prenatal fue similar en ambos grupos: A: 8,4% (13 de 155) y B: 15,7% (11 de 70). La mortalidad posnatal fue A: 16,8% (26 de 155) (p < 0,01), OR 0,52 (IC 95% 0,16 a 1,7) y B: 32,9% (23 de 70), (p <0,01), OR 0,41 (IC 95% 0,20 a 0,83). Las cardiopatías asociadas a anomalías extracardíacas presentaron mayor mortalidad que las cardiopatías congénitas aisladas en el período comprendido hasta las 60 semanas de edad posmenstrual (140 días postérmino). No hubo diferencia en la mortalidad prenatal entre ambos grupos de pacientes.(AU)

Fetal and neonatal mortality in patients with isolated congenital heart diseases and heart conditions associated with extracardiac abnormalities / Mortalidad fetal y neonatal en pacientes con cardiopatías congénitas aisladas y asociadas a anomalías extracardíacas

Congenital malformations are a known cause of intrauterine death; of them, congenital heart diseases (CHDs) are accountable for the highest fetal and neonatal mortality rates. They are strongly associated with other extracardiac malformations and an early fetal mortality. Two hundred and twenty fves cases of CHDs are presented. Of them, 155 were isolated CHDs (group A) and 70 were associated with extracardiac malformations, chromosomal disorders, or genetic syndromes (group B). The overall mortality in group B was higher than that observed in group A (p <0.01). Prenatal mortality was similar in both groups: A: 8.4% (13 out of 155); B: 15.7% (11 out of 70). Postnatal mortality was A: 16.8% (26 out of 155) (p <0.01), OR: 0.52 (95% CI: 0.16-1.7); B: 32.9% (23 out of 70) (p <0.01), OR: 0.41 (95% CI: 0.20-0.83). Heart diseases associated with extracardiac abnormalities had a higher mortality rate than isolated congenital heart diseases in the period up to 60 weeks of postmenstrual age (140 days post-term). No differences were observed between both groups of patients in terms of prenatal mortality.

Las malformaciones congénitas son una causa reconocida de muerte intrauterina. De ellas, las cardiopatías congénitas (CC) ocasionan la mayor mortalidad fetal y neonatal. La asociación con otras malformaciones extracardíacas es elevada y se acompaña de una mortalidad fetal temprana. Se presentan 225 casos de CC. En 155 casos fueron CC aisladas (grupo A) y en 70 se asociaron con malformaciones extracardíacas, cromoso-mopatías o síndromes genéticos (grupo B). La mortalidad global en el grupo B fue mayor con respecto al grupo A (p < 0,01). La mortalidad prenatal fue similar en ambos grupos: A: 8,4% (13 de 155) y B: 15,7% (11 de 70). La mortalidad posnatal fue A: 16,8% (26 de 155) (p < 0,01), OR 0,52 (IC 95% 0,16 a 1,7) y B: 32,9% (23 de 70), (p <0,01), OR 0,41 (IC 95% 0,20 a 0,83). Las cardiopatías asociadas a anomalías extracardíacas presentaron mayor mortalidad que las cardiopatías congénitas aisladas en el período comprendido hasta las 60 semanas de edad posmenstrual (140 días postérmino). No hubo diferencia en la mortalidad prenatal entre ambos grupos de pacientes.

Fetal and neonatal mortality in patients with isolated congenital heart diseases and heart conditions associated with extracardiac abnormalities. / Fetal and neonatal mortality in patients with isolated congenital heart diseases and heart conditions associated with extracardiac abnormalities.

Congenital malformations are a known cause of intrauterine death; of them, congenital heart diseases (CHDs) are accountable for the highest fetal and neonatal mortality rates. They are strongly associated with other extracardiac malformations and an early fetal mortality. Two hundred and twenty fves cases of CHDs are presented. Of them, 155 were isolated CHDs (group A) and 70 were associated with extracardiac malformations, chromosomal disorders, or genetic syndromes (group B). The overall mortality in group B was higher than that observed in group A (p <0.01). Prenatal mortality was similar in both groups: A: 8.4

(13 out of 155); B: 15.7

(11 out of 70). Postnatal mortality was A: 16.8

(26 out of 155) (p <0.01), OR: 0.52 (95

CI: 0.16-1.7); B: 32.9

(23 out of 70) (p <0.01), OR: 0.41 (95

CI: 0.20-0.83). Heart diseases associated with extracardiac abnormalities had a higher mortality rate than isolated congenital heart diseases in the period up to 60 weeks of postmenstrual age (140 days post-term). No differences were observed between both groups of patients in terms of prenatal mortality.

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 SpO(2) 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 bottle's nipple design mimics mom's breast in shape and feel, and the bottle vents to air when the child sucks on the nipple. The other system was the hospital's 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. SpO(2) 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.

Fisiopatología de la enterocolitis necrotizante (ECN) / Pathophysiology of necrotizing enterocolitis (NEC)

La enterocolitis necrotizante (ECN) es la emergencia gastrointestinal más frecuente en recién nacidos (RN)de pretérmino; pese a ello su patogenia es aún motivo de investigación; el tratamiento es difícil y frecuentementeha probado no ser el más adecuado y hasta el momento no se ha encontrado una estrategia de prevención realmenteeficaz.1 A pesar de que el uso de corticoides prenatales podría disminuir su incidencia,2 como observamos ennuestro laboratorio, no tendría la misma acción en los seres humanos. En este contexto de comprensión de las bases biológicas de la génesis de la entidad enmarcamos la presente revisión bibliográfica.

[Nosocomial infections in a neonatal unit: surveillance program]. / Infecciones nosocomiales en una Unidad de Cuidados Neonatales: programa de vigilancia epidemiológica.

INTRODUCTION: Nosocomial infections in neonatal units are frequent and require having a surveillance program which allows detection and implementation of preventive strategies. OBJECTIVE: To determine the incidence and distribution of hospital infections and the rate of use of devices in a neonatal unit compared with international standards. METHODS: Epidemiological, observational, analytical, prospective cohort study. We developed and carried out a monitoring program, stratifying infants by birth weight, recording the use of central catheters, mechanical ventilation, parenteral nutrition and bladder catheter. We calculated the total patient days, the device utilization rates and episodes of hospital infection. The data were compared with those of the National Nosocomial Infection Surveillance. RESULTS: 1530 infants were admitted to the Neonatal Care Unit from 01/01/2006 to 31/12/2008 totaling 22 237 days patients. We identified 138 episodes of hospital infections, adjusted overall rate 6.23 episodes per 1000 patient/days. Overall rates of devices' use were: central catheter 32.3%, mechanical ventilation 14.2%, bladder catheter 4.6%. The overall rate of nosocomial infection associated with central catheter was 8.6 ‰. All groups had rates within the published rates, except the group of infants <1000 grams (19.7 ‰), that exceeded the 90th percentile. With regard to ventilator associated pneumonia (overall rate 1.9‰), rates were comparable. CONCLUSION: The description of the occurrence and distribution of nosocomial infections and their association with risk factors could be determined and generally showed to be found within the published percentiles.

Infecciones nosocomiales en una Unidad de Cuidados Neonatales: programa de vigilancia epidemiológica / Nosocomial infections in a neonatal unit: surveillance program

Introducción. Las infecciones nosocomiales en Unidades Neonatales son hechos frecuentes que obligan a contar con un programa de vigilancia epidemiológica que permita su detección y la toma de medidas para su prevención. Objetivo. Determinar la incidencia y distribución de las infecciones nosocomiales y la tasa de utilización de dispositivos en una Unidad de Cuidados Neonatales en comparación con estándares internacionales. Métodos. Estudio observacional y descriptivo de una cohorte prospectiva. Implementamos un programa de vigilancia en el que se agrupó a los neonatos según peso al nacer y se registró la utilización de catéteres centrales, asistencia respiratoria, nutrición parenteral y sonda vesical. Se calcularon los días/pacientes totales, las tasas de utilización de dispositivos y los episodios de infección nosocomial. Los datos se compararon con los del National Nosocomial Infection Surveillance. Resultados. Ingresaron 1530 recién nacidos a la Unidad de Cuidados Neonatales entre el 01/01/2006 y el 31/12/2008, sumando 22 237 días/paciente. Se identificaron 138 episodios de infección hospitalaria, tasa global ajustada 6,23 episodios por cada 1000 días/paciente. Las tasas globales de utilización de dispositivos fueron: catéter central 32,3%, asistencia respiratoria 14,2%, sonda vesical 4,6%. La tasa global de infección hospitalaria asociada a catéter central fue 8,6‰; todos los grupos arrojaron tasas acordes a las publicadas, excepto el grupo <1000 gramos (19,7‰), que superó el percentilo 90. Con respecto a neumonía asociada con respirador (tasa global 1,9‰), las tasas fueron equiparables. Conclusión. La descripción de la incidencia y distribución de las infecciones nosocomiales y su asociación con factores de riesgo pudieron ser determinadas y, en general, mostraron hallarse dentro de los percentilos publicados.

Introduction. Nosocomial infections in neonatal units are frequent and require having a surveillance program which allows detection and implementation of preventive strategies. Objective. To determine the incidence and distribution of hospital infections and the rate of use of devices in a neonatal unit compared with international standards. Methods. Epidemiological, observational, analytical, prospective cohort study. We developed and carried out a monitoring program, stratifying infants by birth weight, recording the use of central catheters, mechanical ventilation, parenteral nutrition and bladder catheter. We calculated the total patient days, the device utilization rates and episodes of hospital infection. The data were compared with those of the National Nosocomial Infection Surveillance. Results. 1530 infants were admitted to the Neonatal Care Unit from 01/01/2006 to 31/12/2008 totaling 22 237 days patients. We identified 138 episodes of hospital infections, adjusted overall rate 6.23 episodes per 1000 patient/days. Overall rates of devices' use were: central catheter 32.3%, mechanical ventilation 14.2%, bladder catheter 4.6%. The overall rate of nosocomial infection associated with central catheter was 8.6 ‰. All groups had rates within the published rates, except the group of infants <1000 grams (19.7 ‰), that exceeded the 90th percentile. With regard to ventilator associated pneumonia (overall rate 1.9‰), rates were comparable. Conclusion. The description of the occurrence and distribution of nosocomial infections and their association with risk factors could be determined and generally showed to be found within the published percentiles.

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.

[Effects of prenatal steroids in the development of necrotizing enterocolitis in Wistar rat neonates]. / 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 de la administración de glucocorticoides prenatales en el desarrollo de la enterocolitis necrosante en neonatos de rata wistar / Effects of prenatal steroids in the development of necrotizing enterocolitis in wistar rat neonates

Objetivos. Estudiar el efecto de la administración prenatal de corticoides en la evolución clínica y el patrón histopatológico de la enterocolitisnecrosante (ECN), en un modelo experimental.Métodos. Se incluyeron neonatos de rata Wistar.El grupo de estudio (GT) recibió tratamiento con hidrocortisona (5 mg/kg) intraperitoneal, 24 y 48 h antes de la cesárea. El control (GC) recibióigual volumen de solución fisiológica. Los neonatos fueron mantenidos en incubadora a 35ºC sin exposición a leche materna. Se alimentaron porsonda orogástrica c/3 h. Se indujo ECN mediante hipoxia/hipotermia, tres veces al día durante 72 h.Se realizó resección intestinal completa e histopatología con asignación de puntaje de lesión.Resultados. Los signos de ECN fueron irritabilidad y mal estado general, distensión abdominal, intolerancia alimentaria, eritema de pared y hematoquezia.El 60 por ciento (n= 9) del GC (n= 16) presentó al menos 1 signo clínico contra 40 por ciento (n= 6) del GT (n= 15). La aparición de signos clínicos y la evolución de los animales del GT llevó, objetivamente, un curso más leve y atenuado comparado con el GC. La mortalidad del GC fue del 40 por ciento contra 20 por ciento del GT. El estudio microscópico mostró que un 80 por ciento del GC presentaba histopatología compatible con ECN, con grados variables de lesión (50 por ciento de grado 3-4, correspondiente al máximodaño), mientras que solo 40 por ciento de los GT presentaba un patrón histológico compatible (p <0,05).Conclusiones. El tratamiento prenatal con glucocorticoides demostró ser eficaz en la atenuación de la presentación clínica de la ECN en ratas Wistar.

Efectos de la administración de glucocorticoides prenatales en el desarrollo de la enterocolitis necrosante en neonatos de rata wistar / Effects of prenatal steroids in the development of necrotizing enterocolitis in wistar rat neonates

Objetivos. Estudiar el efecto de la administración prenatal de corticoides en la evolución clínica y el patrón histopatológico de la enterocolitisnecrosante (ECN), en un modelo experimental.Métodos. Se incluyeron neonatos de rata Wistar.El grupo de estudio (GT) recibió tratamiento con hidrocortisona (5 mg/kg) intraperitoneal, 24 y 48 h antes de la cesárea. El control (GC) recibióigual volumen de solución fisiológica. Los neonatos fueron mantenidos en incubadora a 35ºC sin exposición a leche materna. Se alimentaron porsonda orogástrica c/3 h. Se indujo ECN mediante hipoxia/hipotermia, tres veces al día durante 72 h.Se realizó resección intestinal completa e histopatología con asignación de puntaje de lesión.Resultados

Efectos del destete temprano sobre el comportamiento adulto en un modelo animal / Early weaning and adult behavioral disorders in an animal model

El destete temprano ha demostrado ser un factor que disminuye la resistencia orgánica de los animales contra condiciones adversas. La prueba de natación forzada se diseñó para experimentar la defensa del animal frente a un estímulo estresante. La conducta activa como el escalar se interpreta como una modelización experimental de voluntad o capacidad activa de escape. Bajo la hipótesis de que el destete temprano podría tener manifestaciones en la vida adulta relacionadas con la defensa frente al estrés, nuestro objetivo fue analizar la conducta de escalado o escape, durante una prueba de natación forzada,en animales adultos que habían sido destetados precozmente. Se utilizaron 20 ratas Wistar (4 meses de edad), divididas en dos grupos: G1 con destete temprano y G2 control. La unidad de análisis o tip, se refirió a la cantidad de veces que el animal presentó la conducta de escape a lo largo de 5 minutos. Se hallaron diferencias estadísticamente significativas entre los tips de G1 y G2 (15,8 más menos 4,15 contra 21,4 más menos 4,14, p< 0,05). Por otra parte, se encontró también una diferencia significativa entre las ratas hembra y los machos. El presente estudio permitiría elucidar experimentalmente las acciones que en la vida adulta del individuo ocasionan alteraciones tempranas en los vínculos primarios.

Early weaning (EW) has proven to be a factor that decreases the animal’s 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 correlateswhen 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 inthe more primary bonds.

Efectos del destete temprano sobre el comportamiento adulto en un modelo animal / Early weaning and adult behavioral disorders in an animal model

El destete temprano ha demostrado ser un factor que disminuye la resistencia orgánica de los animales contra condiciones adversas. La prueba de natación forzada se diseñó para experimentar la defensa del animal frente a un estímulo estresante. La conducta activa como el escalar se interpreta como una modelización experimental de voluntad o capacidad activa de escape. Bajo la hipótesis de que el destete temprano podría tener manifestaciones en la vida adulta relacionadas con la defensa frente al estrés, nuestro objetivo fue analizar la conducta de escalado o escape, durante una prueba de natación forzada,en animales adultos que habían sido destetados precozmente. Se utilizaron 20 ratas Wistar (4 meses de edad), divididas en dos grupos: G1 con destete temprano y G2 control. La unidad de análisis o tip, se refirió a la cantidad de veces que el animal presentó la conducta de escape a lo largo de 5 minutos. Se hallaron diferencias estadísticamente significativas entre los tips de G1 y G2 (15,8 más menos 4,15 contra 21,4 más menos 4,14, p< 0,05). Por otra parte, se encontró también una diferencia significativa entre las ratas hembra y los machos. El presente estudio permitiría elucidar experimentalmente las acciones que en la vida adulta del individuo ocasionan alteraciones tempranas en los vínculos primarios.(AU)

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 correlateswhen 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 inthe more primary bonds.(AU)