ASSESSMENT OF LUNG FUNCTION AND GROWTH IN YOUNG CHILDREN

At present there is no methodology available for assessing lung function
and growth in young children that is painless, non-threatening, fast and at
the same time is sensitive to early abnormalities in airways function or
ventilization inhomogeneity. Thus at present our knowledge of patterns of
lung growth and functions as they relate to age, sex, size, and lung
disease is scanty. Similarly, we do not have the methods or basic
information required to assess risk factors in young children for the
possible development of chronic lung disease such as passive smoking or
viral respiratory tract infections. One of the priorities of the 1983 NIH
Workshop On Passive Smoking was the development of such methods. The
objectives of this proposal are: 1) to develop a methodology appropriate
for assessing lung growth and function in young children; (2) to determine
the precision, specifically, and variability of the method and to develop
reference standards for young children; (3) to test the hypothesis that the
method to be used has the sensitivity required to separate out "healthy"
from "non-healthy;" (4) to test the hypothesis that lung growth is
diffferent in boys and girls; (5) to test the hypothesis that ventilation
homogeneity changes with age; and (6) to use the methodoligy which is
developed in a long-term collaboarative study of the natural history of
alpha1 antitrypsin defidiency.
The method to be used is on-line computerized moment analysis of
multibreath nitrogen washout (MBNW). The technique requires only that the
subject quietly breathe oxygen for less than 2 minutes, and the analysis of
the curve is independent of body size, lung size, tidal volume, or
respiratory rate. The data obtained from the curve include functional
residual capacity, moments 0, 1 and 2 of the MBNW curve, moment ratios,
lung clearance index, and other indices of the washout. The required
software has been developed and preliminary data has been obtained from 36
healthy children ages 2-6 years, 10 children with cystic fibrosis of the
same age, and 5 young healthy adults. The data to date indicate that
moment analysis of MBNW curves has the ability to fulfill the objectives of
the proposal.
The long-range plans are to use the information obtained from this study in
long-term studies of risk factors for the development of chronic lung
disease. The beginnings of one such study, a long-term collaborative
description of the natural history of alpha1 antitrypsin deficiency, is
included as part of the grant proposal.