| 2005 | 2006 | |
| Mean age (years) | 68 (SD 8.8) | 68 (SD 11) |
| Male | 16/30 (53%) | 25/43 (58%) |
| History of T2RF | 6/30 (20%) | 10/43 (23%) |
| FEV1 | 0.69L (SD 0.19) | 0.89L (SD 0.52) |
| Brought by ambulance | 16/30 (53%) | 32/43 (74%) |
| O2 ⩾40% in the ambulance | 13/16 (81%) | 20/32 (63%) |
| Blood gas performed | 26/30 (87%) | 35/43 (81%) |
| Mean pH | 7.363 (SD 0.12) | 7.402 (SD 0.13) |
| pH <7.3 | 8/26 (SD 31%) | 6/35 (SD 17%) |
| Mean PaCO2 | 7.58 kPa | 7.44 kPa |