MRC grade | Number of cases | SpO2 (%) range | SpO2 (%) quartiles* | Corrected* number (%) |
“0” | 19 | 78.5–99 | 90.7, 94.5, 96.2 | 19 (22) |
1 | 51 | 83.5–98 | 93.6, 95.5, 96.5 | 51 (60) |
2 | 15 | 80.8–98 | 85.6, 90.5, 93.1 | 15 (18) |
3 | 2 | 89–92.5 | 89.1, 89.2, 90.8 | 0 |
4 | 1 | 95–95 | 95.0, 95.0, 95.0 | 0 |
5 | 0 | – | – | 0 |
↵* Excludes patients with severe pulmonary hypertension (n =2), or severe emphysema (n = 1).