Table 4.

Receiver operating characteristic properties for prediction of weaning failure

	AUROC (95% CI)	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Cutoff value
Respiratory rate (baseline)	0.80 (0.65–0.91)*	65	84	73	78	> 23
RSBI (baseline)	0.76 (0.61–0.88)*	88	56	58	88	> 39.5
PPI (baseline)	0.57 (0.41–0.72)	33	100	100	67	> 6.1
PPI ratio (15 min)	0.71 (0.55–0.84)*	56	84	71	72	≤ 0.88
PPI ratio (30 min)	0.83 (0.69–0.93)*	94	72	71	95	≤ 1.41

^*Denotes statistical significance (P value < 0.05). AUROC Area under receiver operating characteristic curve, NPV negative predictive value, PPI peripheral perfusion index, PPV positive predictive value. RSBI rapid shallow breathing index