Growth of lung parenchyma in infants and toddlers with chronic lung disease of infancy.

RATIONALE: The clinical pathology describing infants with chronic lung disease of infancy (CLDI) has been limited and obtained primarily from infants with severe lung disease, who either died or required lung biopsy. As lung tissue from clinically stable outpatients is not available, physiological measurements offer the potential to increase our understanding of the pulmonary pathophysiology of this disease. OBJECTIVES: We hypothesized that if premature birth and the development of CLDI result in disruption of alveolar development, then infants and toddlers with CLDI would have a lower pulmonary diffusing capacity relative to their alveolar volume compared with full-term control subjects. METHODS: We measured pulmonary diffusing capacity and alveolar volume, using a single breath-hold maneuver at elevated lung volume. Subjects with chronic lung disease of infancy (23-29 wk of gestation; n = 39) were compared with full-term control subjects (n = 61) at corrected ages of 11.6 (4.8-17.0) and 13.6 (3.2-33) months, respectively. MEASUREMENTS AND MAIN RESULTS: Alveolar volume and pulmonary diffusing capacity increased with increasing body length for both groups. After adjusting for body length, subjects with CLDI had significantly lower pulmonary diffusing capacity (2.88 vs. 3.23 ml/min/mm Hg; P = 0.0004), but no difference in volume (545 vs. 555 ml; P = 0.58). CONCLUSIONS: Infants and toddlers with CLDI have decreased pulmonary diffusing capacity, but normal alveolar volume. These physiological findings are consistent with the morphometric data obtained from subjects with severe lung disease, which suggests an impairment of alveolar development after very premature birth.

Ventilation homogeneity improves with growth early in life.

Some studies have suggested that lung clearance index (LCI) is age-independent among healthy subjects early in life, which implies that ventilation distribution does not vary with growth. However, other studies of older children and adolescents suggest that ventilation becomes more homogenous with somatic growth. We describe a new technique to obtain multiple breath washout (MBWO) in sedated infants and toddlers using slow augmented inflation breaths that yields an assessment of LCI and the slope of phase III, which is another index of ventilation inhomogeneity. We evaluated whether ventilation becomes more homogenous with increasing age early in life, and whether infants with chronic lung disease of infancy (CLDI) have increased ventilation inhomogeneity relative to full-term controls (FT). FT (N = 28) and CLDI (N = 22) subjects between 3 and 28 months corrected-age were evaluated. LCI decreased with increasing age; however, there was no significant difference between the two groups (9.3 vs. 9.5; P = 0.56). Phase III slopes adjusted for expired volume (S(ND)) increased with increasing breath number during the washout and decreased with increasing age. There was no significant difference in S(ND) between full-term and CLDI subjects (211 vs. 218; P = 0.77). Our findings indicate that ventilation becomes more homogenous with lung growth and maturation early in life; however, there is no evidence that ventilation inhomogeneity is a significant component of the pulmonary pathophysiology of CLDI.

Análise descritiva dos pacientes com fibrose cística em acompanhamento da Unidade de Pneumologia Pediátrica de um hospital universitário de Porto Alegre-RS / Descriptive analysis of cystic fibrosis patients followed by the Pediatric Pulmonology Unit of a university hospital in Porto Alegre-RS

Objetivos: Descrever o perfil de pacientes acompanhados num centro de tratamento de médio porte, especializado em fibrose cística, e comparar os dados obtidos com os encontrados na literatura atual. Foram analisados e correlacionados dados de importância para o seguimento clínico dos pacientes com fibrose cística obtidos no banco de dados de acompanhamento dos mesmos pacientes. Os resultados foram expressos em médias ± desvio padrão (DP) ou medianas e amplitude interquartil 25-75%, conforme e diatribuição das variáveis. Resultados: Foram estudados 26 pacientes do sexo masculino e 22 do feminino. A idade mediana do diagnóstico foi de 0,98 anos. Dos 48 pacientes, 89,6% apresentam insuficiência pancreática e 29,1% mostraram pelo menos um cultura positiva para Pseudomonasaeroginosa nos últimos 6 meses. Apresentavam redução dos parâmetros de função pulmonar o grupo com insuficiência pancreática (84 versus 112%; p=0,005) e os portadores de infecção crônica por P. aeroginosa (75 versus 85%; p= 0,006). Conclusões: Os dados obtidos em nosso estudo mostraram que este grupo de pacientes se apresenta de maneira concordante aos dados disponíveis na literatura quanto às características analisadas da doença. Contudo, há uma exceção marcante quanto ao diagnóstico da mesma, ainda muito tardiamente realizado no Brasil.