Reference values of interrupter respiratory resistance in healthypreschool white children

摘要

BACKGROUND—Interrupter respiratory resistance (Rint) is reported to be useful in evaluating lung function in poorly collaborating patients. However, no reference values are available from large samples of preschool children using the standard interrupter method. The aim of this study was to define reference Rint values in a population of healthy preschool children.
METHODS—Rint was assessed without supporting the cheeks in children with no history of wheeze from six kindergartens. To evaluate the effects of upper airway compliance on Rint in healthy children, an additional group of preschool children with either no history of wheeze or no respiratory symptoms at the time of testing underwent Rint measurements in our lung function laboratory with and without supporting the cheeks. Short term (about 1 minute apart) and long term (mean 2.5 months apart) repeatability of Rint measurements (2 SDs of the mean paired difference between measurements) was also assessed in children referred for cough or wheeze.
RESULTS—A total of 284 healthy white children (age range 3.0-6.4 years) were evaluated. Mean inspiratory and expiratory Rint (RintI and RintE) did not differ significantly in boys and girls. Age, height, and weight showed a significant inverse correlation with both RintI and RintE in the univariate analysis withlinear regression. Multiple regression with age, height, and weight asthe independent variables showed that all three variables weresignificantly and independently correlated with RintI,whereas only height was significantly and independently correlated withRintE. Supporting the cheeks had no significant effect onRintI (n=29, median 0.673 v0.660 kPa/l.s, p=0.098) or RintE (n=39, median 0.702 v 0.713 kPa/l.s, p=0.126). Short termrepeatability was 0.202 kPa/l.s for RintI (n=50) and0.242 kPa/l.s for RintE (n=69). Long term repeatability was 0.208 kPa/l.s for RintE (n=26).
CONCLUSIONS—We havereported reference Rint values in preschool white children and havedemonstrated the usefulness of this technique in assessing lungfunction in this age group.