Receiver operator curve analyses for predicting hypercapnia: sensitivity and specificity ranges for differing cut-off levels
| Cut-off level | Sensitivity (%, 95% CI) | Specificity (%, 95% CI) |
|---|---|---|
| SpO2 | ||
| <95% | 83 (76 to 88) | 63 (51 to 73) |
| <93% | 62 (54 to 70) | 75 (65 to 85) |
| <92% | 53 (45 to 61) | 86 (76 to 92) |
| FVC | ||
| <2.5 L | 80 (73 to 86) | 60 (50 to 71) |
| <2.8 L | 88 (82 to 92) | 51 (39 to 62) |
| <3.0 L | 90 (84 to 94) | 41 (30 to 52) |
| <3.1 L | 90 (85 to 94) | 40 (29 to 51) |
| <3.6 L | 96 (91 to 98) | 24 (15 to 35) |
FVC, forced vital capacity; SpO2, oxygen saturations.