Hyperoncotic enhancement of fetal pulmonary growth after tracheal occlusion: an alveolar and capillary morphometric analysis.

BACKGROUND/PURPOSE: Previous work has shown that intrapulmonary delivery of oncotic agents enhance overall lung growth after late gestational fetal tracheal occlusion (TO). This study was a post hoc analysis aimed at determining whether actual alveolar and capillary hyperplasias are maximized in this setting.

METHODS

Twenty-one near term fetal lambs were evenly divided into 4 groups: group I comprised sham-operated controls; group II had TO alone; and groups III and IV underwent TO and intratracheal infusion of equal amounts of either saline or 25% albumin, respectively. Approximately 2 weeks thereafter, their lungs were examined by detailed alveolar and capillary morphometry before birth. Statistical analysis included analysis of variance and the Bonferroni correction for multiple comparisons (P < .05).

RESULTS

Total alveolar and capillary numbers, as well as total alveolar surface area, were significantly higher in group IV and lower in group I compared with all other groups, with no differences between groups II and III. Alveolar capillary load was normal in all groups.

CONCLUSIONS

Intrapulmonary delivery of concentrated albumin safely enhances short-term alveolar and capillary hyperplasia in a late gestational model of fetal TO. This therapeutic concept may allow for TO to be effective and predictable when performed late in gestation.