Table 3 Breathing Reserves of the cohorts as defined by direct MVV, traditional indirect MVV formula (FEV1 × 35) and the novel indirect MVV formula ((FEV1 × 20.1) + 15.4)
Derivation Cohort | Validation Cohort | |
|---|---|---|
N measurements | 98 | 73 |
Measured VEpeak (L/min) | 44.3 (14) | 42.4 (15) |
MVV Technique (L/min) | ||
1. Direct | 67.4 (23.0) | 76(28) |
BR (L/min) | 23.0 (17) | 34.2 (21) |
VEpeak: MVV | 0.68 (0.19) | 0.58 (0.18) |
Proportion VEpeak≥0.85 MVV | 20 [26%] | 7 [10%] |
2. Indirect: FEV1 × 35 | 54(18) | 63(23) |
BR (L/min) | 9.8 (13) | 21 (17) |
VEpeak:MVV | 0.86 (0.23) | 0.70 (0.21) |
Proportion VEpeak≥0.85 MVV | 46 [47%] | 16 [22%] |
3. Indirect: (FEV1 × 20.1) + 15.4 | 46.5 (10) | 51.0 (13.2) |
BR (L) | 2.1 (10) | 9.5 (11.9) |
VEpeak:MVV | 0.96 | 0.82 (0.22) |
Proportion VEpeak≥0.85 MVV | 68 [69%] | 33 [45%] |
Inspiratory Capacity Analysis | ||
N measurements | 52 | 44 |
Inspiratory Capacity (L) | 1.39 (0.52) | 1.51 (0.62) |
VTmax (L) | 0.99 (0.38) | 1.12 (0.45) |
VTmax:IC | 0.81 (0.2) | 0.76 (0.18) |
Proportion VTmax:IC ≥ 0.70 | 38 [73%] | 26 [59%] |