Table 3

Prediction of death from respiratory failure using minimum ratio of arterial to alveolar oxygen tension (a/A)

a/A ⩽	Sensitivity	Specificity	Positive predictive value	Negative predictive value	Positive likelihood ratio	Negative likelihood ratio
0.02	0.11	0.99	0.80	0.79	13.71	0.89
0.06	0.63	0.93	0.73	0.90	9.43	0.40
0.10	0.91	0.66	0.44	0.96	2.68	0.13
0.14	0.94	0.51	0.36	0.97	1.92	0.11
0.18	0.94	0.32	0.29	0.95	1.38	0.18
0.22	0.97	0.26	0.28	0.97	1.31	0.11