Table 2.
Changes from pretest probability of weaning success to post-test probability for different likelihood ratios obtained in several studies that evaluated the f/VT ratio
| Post-test probability of weaning success (%) | ||||||||
| Likelihood ratio of a positive test result* | Likelihood ratio of a negative test result† | |||||||
| Pretest probability of weaning success (%) | 1.45 | 1.51 | 2.69 | 2.74 | 0.05 | 0.09 | 0.27 | 0.36 |
| 30 | 38 | 39 | 53 | 54 | 2 | 4 | 10 | 13 |
| 40 | 49 | 50 | 64 | 65 | 3 | 6 | 15 | 19 |
| 50 | 59 | 60 | 73 | 73 | 5 | 8 | 21 | 26 |
| 60 | 68 | 69 | 80 | 80 | 7 | 12 | 29 | 35 |
| 70 | 70 | 77 | 86 | 86 | 10 | 17 | 39 | 46 |
| 80 | 85 | 86 | 91 | 92 | 17 | 26 | 52 | 59 |
*Positive test result is a value of rapid shallowbreathing index (f/VT) lower than 105 or 100; †negative testresult is a value of f/VT higher than 105 or 100.