Lung Function Data
Research-quality FRC and FEV0.5 data were obtained in
96% and 100% of infants, respectively. As demonstrated in Table 2, the
forced vital capacity (FVC) z-score was decreased, but all other RVRTC
data were within normal limits. In contrast to the RVRTC data, the mean
FRC z-score was significantly elevated at 2.18. Figure 2 demonstrates
that the proportion of patients with hyperinflation (44%) was
significantly higher than infants with diminished FEV0.5(7%) (p<0.001). Mean RR was also significantly elevated, and
correlated with FRC (Figure 3) with a Spearmen correlation coefficient
of 0.377 (p=0.01). Using logistic regression to calculate Youden’s
index, we found that a RR cutoff of 36 breaths/min resulted in 92%
sensitivity to detect hyperinflation with 32% specificity.