Figure 5.
The effect of methacholine and 80% oxygen on lung inflation. Gray markers indicate room air conditions, and black indicates 80% oxygen. Open circles represent baseline, and closed circles represent postmethacholine data. P values reflect the results from pairwise comparisons. In A and B, the bold lines with error bars represent mean and SD values within each subregion. In C, the bold black and solid gray lines with large closed circles represent mean values. (A) Only under room air conditions was there a significant increase in relative gas fraction (Fgas) within the lowest quartile of ventilating lung (sVlow) region. (B) There was a significant decrease in relative Fgas in the median and highest quartiles of ventilating lung, sVhigh region, after methacholine under room air only. (C) Relative Fgas was higher in sVlow subregions with lower estimated alveolar oxygen partial pressure (PaO2).