Table 3.
The time course of the changes in PtCO2 in the treatment groups
| (i) The proportion of patients with a rise in PtCO2 ≥4 mmHg | ||||
| Time | High concentration n (%) | Titrated n (%) | Relative risk (95% CI) | P value |
| 20 minutes | 19 (26.4%) | 4 (5.3%) | 5.0 (1.8 to 13.8) | <0.001 |
| 40 minutes | 27 (37.5%) | 8 (10.7%) | 3.5 (1.7 to 7.2) | <0.001 |
| 60 minutes | 36 (50.0%) | 11 (14.7%) | 3.4 (1.9 to 6.2) | <0.001 |
| (ii) The mean change in PtCO2 (mmHg) | ||||
| Time | High concentration mean (SD) | Titrated mean (SD) | Difference (95% CI) | P value |
| 20 minutes | 1.9 (3.4) | −0.2 (2.7) | 2.1 (1.1 to 3.1) | <0.001 |
| 40 minutes | 2.9 (3.7) | 0.5 (3.6) | 2.4 (1.2 to 3.6) | <0.001 |
| 60 minutes | 3.6 (3.9) | 0.9 (3.7) | 2.7 (1.5 to 3.9) | <0.001 |