Table 4. The sensitivity and specificity at Youden's J cut-off points for the ROX and mROX and their efficacy at p=0.01.

ROX: Respiratory rate-oxygenation index, mROX: modified Respiratory rate-oxygenation index.

Index/time points	Parameters	Cut-point	Sensitivity	Specificity
ROX at baseline	Youden's J	4.59	0.643	0.692
	Efficacy at P = 0.01	7.23	0.286	1
mROX at baseline	Youden's J	4.1	0.571	0.846
	Efficacy at P = 0.01	6.8	0.286	1
ROX at six hours	Youden's J	4.47	0.643	0.769
	Efficacy at P = 0.01	6.04	0.286	1
mROX at six hours	Youden's J	3.34	0.857	0.769
	Efficacy at P = 0.01	5.57	0.214	1