TABLE 2.
Effect of wash-in methodology on wash-in time and other parameters
| Open | Rebreathe | p-value for open versus rebreathe | |
| Healthy volunteers | |||
| Total wash-in time s | 202 (142–229) | 101 (89–142) | 0.0005 |
| Cumulative inspired volume L | 19.8±4.3 | 17.9±5.4 | 0.2 |
| Wash-in incompleteness % | 1.25±0.36 | 0.53±0.60 | 0.003 |
| Median end wash-in CO2 % | 1.4 (1.0–3.5) | ||
| Cystic fibrosis | |||
| Total wash-in time s | 230 (204–280)* | 156 (132–173)* | <0.0001 |
| Cumulative inspired volume L | 38.4±8.4# | 32.2±6.2# | 0.01 |
| Wash-in incompleteness % | 1.76 (0.74) | 1.18 (0.82)* | 0.0007 |
| Median end wash-in CO2 % | 1.3 (1.1–1.7) |
Data are presented as median (interquartile range) or mean±sd, unless otherwise stated. *: p<0.05 for healthy volunteers versus CF; #: p<0.0001 for healthy volunteers versus CF.