- Comparison of fraction of expired oxygen values within and between groups.
| Time | Group 1 n (33) | Group 2 n (33) | P-value* | ||
|---|---|---|---|---|---|
| Mean±SD | Median (min.–max.) | Mean±SD | Median (min.–max.) | ||
| T1 | 81.64 ± 7.07 | 83 (62–91)c | 84.27 ± 9.89 | 88 (56–95)b | 0.025 |
| T2 | 76.27 ± 6.54 | 77 (66–89)c | 80.85 ± 8.34 | 82 (62–98)b | 0.009 |
| T3 | 53.70 ± 6.07 | 54 (42–65)b | 51.58 ± 3.86 | 51 (45–60)a | 0.086 |
| T4 | 49.21 ± 4.24 | 50 (41–54)a | 49.30 ± 3.95 | 50 (41–54)a | 0.732 |
| P-value† | <0.001 | <0.001 | |||
* Mann-Whitney U test; †Friedman test, SD: standard deviation; Min: minimum; Max: maximum, Ggoup 1: 3 min at normal tidal volume, Group 2: 30 s with the 4 deep vital capacity technique, T1: after preoxygenation, T2: immediately after intubation, T3: at the 3rd min after intubation, T4: at the 7th min after intubation, *P-value: Comparison between groups. †P-value: Compared within the group, a-c. There is no difference between times with the same letter in a group.