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.