Table 1
| Previous NIV | Initial pH | 12-hour pH | Initial pCO2 (kPa) | 12-hour pCO2 (kPa) | Initial IPAP (cm H2O) | 12-hour IPAP | Time to normal pH (hrs) |
| Yes (Mean (SD)) | 7.24 (0.2) | 7.29 (0.2) | 12.4 (4.9) | 10.3 (0.2) | 14 (4.6) | 22.3 (8.2) | 19.6 (19) |
| No (Mean (SD)) | 7.19 (0.1) | 7.33 (0.6) | 12 (3.1) | 8.1 (0.2) | 12 (2.5) | 19.5 (4.5) | 25.6 (4) |