Changes in lung clearance index (LCI) and forced expiratory volume in 1 s (FEV1) for the overall study population and for sulfur hexafluoride (SF6) and nitrogen (N2) multiple breath washout (MBW) studies separately
| Overall | SF6 | N2 | p-value (SF6 versus N2) | |
| Subjects n | 192 | 94 | 98 | |
| LCI at admission | 12.9 (12.5–13.3) | 13.6 (13.0–14.2) | 12.3 (11.6–12.9) | 0.297 |
| Absolute change in LCI | −0.40 (−0.60– −0.19) | −0.49 (−0.78– −0.20) | −0.31 (−0.60– −0.02) | 0.044 |
| Relative change in LCI % | −2.52 (−4.06– −0.99) | −2.98 (−5.16– −0.81) | −2.08 (−4.28–0.11) | 0.561 |
| FEV1 % pred at admission | 59.8 (57.2–62.3) | 54.1 (50.7–57.4) | 65.0 (61.4–68.6) | <0.0001 |
| Absolute change in FEV1 L | 0.20 (0.15–0.25) | 0.26 (0.18–0.35) | 0.14 (0.10–0.19) | 0.872 |
| Relative change % | 13.77 (10.38–17.15) | 17.92 (12.16–23.67) | 9.95 (6.23–13.67) | 0.071 |
Data are presented as mean (95% CI), unless otherwise stated. p-values were generated using linear regression with tracer gas as an explanatory variable adjusting for the correlated nature of the data using generalised estimating equation models.