Alveolar formation is dysregulated by restricted nutrition but not excess sedation in preterm lambs managed by noninvasive support.

BACKGROUND: Preterm birth and respiratory support with invasive mechanical ventilation frequently leads to bronchopulmonary dysplasia (BPD). A hallmark feature of BPD is alveolar simplification. For our preterm lamb model of BPD, invasive mechanical ventilation is associated with postnatal feeding intolerance (reduced nutrition) and sedation. In contrast, preterm lambs managed by noninvasive support (NIS) have normal alveolar formation, appropriate postnatal nutrition, and require little sedation. We used the latter, positive-outcome group to discriminate the contribution of reduced nutrition vs. sedation on alveolar simplification. We hypothesized that, restricted nutrition, but not sedation with pentobarbital, contributes to impaired indices of alveolar formation in preterm lambs managed by NIS. METHODS: Preterm lambs managed by NIS for 21d were randomized into three groups: NIS control, NIS plus restricted nutrition, and NIS plus excess sedation with pentobarbital. We quantified morphological and biochemical indices of alveolar formation, as well as mesenchymal cell apoptosis and proliferation. RESULTS: Restricted nutrition impaired morphological and biochemical indices of alveolar formation, and reduced mesenchymal cell apoptosis and proliferation. Excess sedation with pentobarbital did not alter these indices, although mesenchymal cell apoptosis was less. CONCLUSION: Our results demonstrate that restricted nutrition, but not excess sedation, contributes to impaired alveolar formation during the evolution of BPD in chronically ventilated preterm lambs.

Validity and reliability of a nutrition knowledge survey for assessment in elementary school children.

Limited surveys are available to assess the nutrition knowledge of children. The goals of this study were to test the validity and reliability of a computer nutrition knowledge survey for elementary school students and to evaluate the impact of the "Fit Kids 'r' Healthy Kids" nutrition intervention via the knowledge survey. During survey development, a sample (n=12) of health educators, elementary school teachers, and registered dietitians assessed the survey. The target population consisted of first- through fourth-grade students from Salt Lake City, UT, metropolitan area schools. Participants were divided into reliability (n=68), intervention (n=74), and control groups (n=59). The reliability group took the survey twice (2 weeks apart); the intervention and control groups also took the survey twice, but at pre- and post-intervention (4 weeks later). Only students from the intervention group participated in four weekly nutrition classes. Reliability was assessed by Pearson's correlation coefficients for knowledge scores. Results demonstrated appropriate content validity, as indicated by expert peer ratings. Test-retest reliability correlations were found to be significant for the overall survey (r=0.54; P<0.001) and for all subscales: food groups, healthful foods, and food functions (r=0.51, 0.65, and 0.49, respectively; P<0.001). Nutrition knowledge was assessed upon program completion with paired samples t tests. Students from the intervention group demonstrated improvement in nutrition knowledge (12.2+/-1.9 to 13.5+/-1.6; P<0.001), while scores for the control group remained unchanged. The difference in total scores from pre- to post-intervention between the two groups was significant (P<0.001). These results suggest that the computerized nutrition survey demonstrated content validity and test-retest reliability for first- through fourth-grade elementary school children. Also, the study results imply that the Fit Kids 'r' Healthy Kids intervention promoted gains in nutrition knowledge. Overall, the computer survey shows promise as an appealing medium for assessing nutrition knowledge in children.