| <> | High concentration, n (%) | Titrated, n (%) | Relative risk (95% CI) | p Value |
| Change in PtCO2 ⩾4 mm Hg (0.53 kPa) | 36 (50%) | 11 (14.7%) | 3.4 (1.9 to 6.2) | <0.001 |
| Change in PtCO2 ⩾4 mm Hg and PtCO ⩾38 mm Hg (5.05 kPa) | 19 (26.4%) | 5 (6.7%) | 2.7 (1.2 to 6.0) | 0.01 |
| Change in PtCO2 ⩾8 mm Hg (1.06 kPa) | 11 (15.3%) | 2 (2.7%) | 5.7 (1.3 to 25.0) | 0.007 |
PtCO2, transcutaneous CO2.