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.

Alía and Esteban Critical Care 2000 4:72   doi:10.1186/cc660