Cognitive performance of premature infants: association between bronchopulmonary dysplasia and cognitive skills. Cross-sectional study.

CONTEXT AND OBJECTIVE:: Children born prematurely often have worse cognitive performance than those born at term regarding skills such as memory, attention and processing speed. Bronchopulmonary dysplasia may compromise cognitive development. The aims here were: a) To describe the cognitive performance of preterm infants with very low birth weight; b) To investigate its association with bronchopul-monary dysplasia adjusted for sociodemographic, neonatal and post-neonatal factors. DESIGN AND SETTING:: Cross-sectional study developed in a public tertiary-care hospital. METHODS:: To evaluate cognition among 112 children, we applied an intelligence scale (Wechsler scale). The average scores for children with and without bronchopulmonary dysplasia were compared across the fve domains of the scale. Associations with bronchopulmonary dysplasia were investigated for domains that showed signifcant diferences between the two groups. Associations between exposure and outcome were estimated via multivariate logistic regression. RESULTS:: There were no diferences in averages for the full-scale intelligence quotient, verbal intelligence quotient, performance intelligence quotient and general language composite domains. The processing speed quotient was the only domain that presented a signifcant diference between the two groups (P = 0.02). Among the children with bronchopulmonary dysplasia, low full-scale intelligence quotient was observed in 28.1%. In the multivariate analysis, bronchopulmonary dysplasia (odds ratio: 3.1; 95conf-dence interval: 1.1-8.7) remained associated with the outcome of processing speed quotient. CONCLUSION:: Bronchopulmonary dysplasia was an independent risk factor for alteration of the processing speed quotient.

Cognitive performance of premature infants: association between bronchopulmonary dysplasia and cognitive skills. Cross-sectional study / Desempenho cognitivo de prematuros: associação da displasia broncopulmonar com as habilidades cognitivas. Estudo transversal

ABSTRACT CONTEXT AND OBJECTIVE: Children born prematurely often have worse cognitive performance than those born at term regarding skills such as memory, attention and processing speed. Bronchopulmonary dysplasia may compromise cognitive development. The aims here were: a) To describe the cognitive performance of preterm infants with very low birth weight; b) To investigate its association with bronchopul-monary dysplasia adjusted for sociodemographic, neonatal and post-neonatal factors. DESIGN AND SETTING: Cross-sectional study developed in a public tertiary-care hospital. METHODS: To evaluate cognition among 112 children, we applied an intelligence scale (Wechsler scale). The average scores for children with and without bronchopulmonary dysplasia were compared across the fve domains of the scale. Associations with bronchopulmonary dysplasia were investigated for domains that showed signifcant diferences between the two groups. Associations between exposure and outcome were estimated via multivariate logistic regression. RESULTS: There were no diferences in averages for the full-scale intelligence quotient, verbal intelligence quotient, performance intelligence quotient and general language composite domains. The processing speed quotient was the only domain that presented a signifcant diference between the two groups (P = 0.02). Among the children with bronchopulmonary dysplasia, low full-scale intelligence quotient was observed in 28.1%. In the multivariate analysis, bronchopulmonary dysplasia (odds ratio: 3.1; 95conf-dence interval: 1.1-8.7) remained associated with the outcome of processing speed quotient. CONCLUSION: Bronchopulmonary dysplasia was an independent risk factor for alteration of the processing speed quotient.

RESUMO CONTEXTO E OBJETIVO: Crianças nascidas prematuras com frequência apresentam pior desempenho cognitivoque as nascidas a termo em habilidades como memória, atenção, velocidade de processamento. A displasia broncopulmonar pode comprometer o desenvolvimento cognitivo. Os objetivos aqui foram: a) Descrever o desempenho cognitivo de crianças nascidas prematuras com muito baixo peso; b) Investigar sua associação com a displasia broncopulmonar ajustada para fatores sócio-demográfcos, neonatais e pós-neonatais. TIPO DE ESTUDO E LOCAL: Estudo transversal desenvolvido em hospital público de cuidados terciários. MÉTODOS: Para a avaliação cognitiva de 112 crianças, aplicamos a escala de inteligência (Wechsler scale). Foram comparadas as médias dos escores das crianças com e sem displasia broncopulmonar nos cinco domínios da escala. A associação com a displasia broncopulmonar foi investigada para os domínios que apresentaram diferença signifcativa entre os dois grupos. A associação entre a exposição e o desfecho foi estimada por regressão logística multivariada. RESULTADOS: Não houve diferença entre as médias dos domínios do quociente de inteligência total, quociente de inteligência verbal, quociente de inteligência de execução e composto de linguagem geral. O quociente de velocidade de processamento foi o único domínio que apresentou diferença signifcativa entre os dois grupos (P = 0,02). Entre as crianças com displasia broncopulmonar, quociente de inteligência total baixo ocorreu em 28,1%. Na análise multivariada, a displasia broncopulmonar (odds ratio: 3,1; intervalo de confança: 1,1-8,7) permaneceu associada ao desfecho quociente de velocidade de processamento. CONCLUSÃO: A displasia broncopulmonar foi um fator de risco independente para alteração no quociente de velocidade de processamento.

Mental performance of very low birth weight preterm infants: assessment of stability in the first two years of life and factors associated with mental performance.

The aim of this study was to investigate the stability of mental performance of very low birth weight premature infants during the first two years of life, and to identify factors associated with mental performance.The study included 109 children. The Mental Scale of Bayley Scales of Infant Development - Second Edition was administered at 6, 12 and 18-24 months of corrected age. The stability of the scores between assessments was verified by the analysis of variance for repeated measures.The association of the major social and neonatal characteristics with mental development was confirmed using multivariate analysis by linear regression, considering the following outcomes: mental development indices at 6 months, 12 months and between 18-24 months of corrected age. The mean Mental Developmental Index (MDI) was 83.4 (SD: 12.4) at 6 months, 86.4 (SD: 13.9) at 12 months, and 73.4 (SD: 14.5) at 18-24 months. A significant decrease in the mental developmental index (13 points) at 18-24 month corrected age was observed. The Mental development index did not show stability during the first two years of life in this population of preterm infants, except for children with neonatal pneumonia whose performance was unsatisfactory in all assessments. Among the risk factors investigated only male gender and neonatal pneumonia were associated with outcomes.

Neonatal risk factors for respiratory morbidity during the first year of life among premature infants.

CONTEXT AND OBJECTIVE: There have been dramatic increases in very low birth weight infant survival. However, respiratory morbidity remains problematic. The aim here was to verify associations between pulmonary mechanics, pulmonary structural abnormalities and respiratory morbidity during the first year of life. DESIGN AND SETTING: Prospective cohort study at Instituto Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro. METHODS: Premature infants with birth weight < 1500 g were studied. Lung function tests and high-resolution chest tomography were performed before discharge. During the first year, infants were assessed for respiratory morbidity (obstructive airways, pneumonia or hospitalization). Neonatal lung tests and chest tomography and covariables potentially associated with respiratory morbidity were independently assessed using relative risk (RR). RR was subsequently adjusted via logistic regression. RESULTS: Ninety-seven newborn infants (mean birth weight: 1113 g; mean gestational age: 28 weeks) were assessed. Lung compliance and lung resistance were abnormal in 40% and 59%. Tomography abnormalities were found in 72%; respiratory morbidity in 53%. Bivariate analysis showed respiratory morbidity associated with: mechanical ventilation, prolonged oxygen use (beyond 28 days), oxygen use at 36 weeks, respiratory distress syndrome, neonatal pneumonia and patent ductus arteriosus. Multivariate analysis gave RR 2.7 (confidence interval: 0.7-10.0) for simultaneous lung compliance and chest tomography abnormalities. Adjusted RR for neonatal pneumonia and mechanical ventilation were greater. CONCLUSIONS: Upon discharge, there were high rates of lung mechanism and tomography abnormalities. More than 50% presented respiratory morbidity during the first year. Neonatal pneumonia and mechanical ventilation use were statistically significant risk factors.

Lung mechanics and high-resolution computed tomography of the chest in very low birth weight premature infants.

CONTEXT: Premature infant lung development may be affected by lung injuries during the first few weeks of life. Lung injuries have been associated with changes in lung mechanics. OBJECTIVE: To evaluate an association between lung mechanics and lung structural alterations in very low birth weight infants (birth weight less than 1500 g). DESIGN: A cross-sectional evaluation of pulmonary mechanics (lung compliance and lung resistance) and high resolution computed tomography of the chest at the time of discharge, in 86 very low birth weight infants born at Instituto Fernandes Figueira, a tertiary public healthcare institution in Rio de Janeiro, Brazil. Lung compliance and resistance were measured during quiet sleep. High resolution computed tomography was performed using Pro Speed-S equipment. MAIN MEASUREMENTS: Statistical analysis was performed by means of variance analysis (ANOVA/Kruskal Wallis). The significance level was set at 0.05. RESULTS: Abnormal values for both lung compliance and lung resistance were found in 34 babies (43%), whereas 20 (23.3%) had normal values for both lung compliance and lung resistance. The mean lung compliance and lung resistance for the group were respectively 1.30 ml/cm H2O/kg and 63.7 cm H2O/l/s. Lung alterations were found via high-resolution computed tomography in 62 (72%) infants. Most infants showed more than one abnormality, and these were described as ground glass opacity, parenchymal bands, atelectasis and bubble/cyst. The mean compliance values for infants with normal (1.49 ml/cm H2O/kg) high resolution computed tomography, 1 or 2 abnormalities (1.31 ml/cm H2O/kg) and 3 or more abnormalities (1.16 ml/cm H2O/kg) were significantly different (p=0.015). Our data were insufficient to find any association between lung resistance and the number of alterations via high-resolution computed tomography. CONCLUSION: The results show high prevalence of lung functional and tomographic abnormalities in asymptomatic very low birth weight infants at the time of discharge. They also show an association between lung morphological and functional abnormalities.