Table 5.

Prediction of HFNC success based on ROX and ROX-HR cut offs at different time points

	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	LR+	LR−
A. Prediction of HFNC success for patients initiated on HFNC for acute respiratory failure
2-h ROX-HR > 6.80	55.56	74.41	73.17	57.14	2.17	0.60
2-h ROX > 5.80	61.11	67.44	70.21	58.00	1.87	0.58
6-h ROX-HR > 6.80	70.00	57.14	70.00	57.14	1.63	0.53
6-h ROX > 5.80	74.00	57.14	71.15	60.60	1.73	0.46
10-h ROX-HR > 6.80	78.26	58.62	75.00	62.96	1.89	0.37
10-h ROX > 5.80	78.26	58.62	75.00	62.96	1.89	0.37
18-h ROX-HR > 6.80	80.00	55.00	78.05	57.89	1.78	0.36
18-h ROX > 5.80	87.50	35.00	72.92	58.33	1.35	0.36
24-h ROX-HR > 6.80	81.82	64.29	84.39	60.00	2.29	0.28
24-h ROX > 5.80	84.85	57.14	82.35	61.54	1.98	0.27
B. Prediction of HFNC success for patients initiated on HFNC after a planned extubation
2-h ROX-HR > 8.00	82.10	40.00	71.90	54.50	1.37	0.45
2-h ROX > 7.00	78.60	40.00	71.00	50.00	1.31	0.54
6-h ROX-HR > 8.00	74.10	63.60	83.30	50.00	2.04	0.41
6-h ROX > 7.00	74.10	54.50	80.00	46.20	1.63	0.48
10-h ROX-HR > 8.00	84.60	63.60	84.60	63.60	2.32	0.24
10-h ROX > 7.00	84.60	54.50	81.50	60.00	1.86	0.28
18-h ROX-HR > 8.00	82.60	30.00	73.10	42.90	1.18	0.58
18-h ROX > 7.00	78.30	40.00	75.00	44.40	1.31	0.54
24-h ROX-HR > 8.00	66.70	66.70	82.40	46.20	2.00	0.50
24-h ROX > 7.00	71.40	77.80	88.20	53.80	3.22	0.37

HFNC high flow nasal cannula therapy, PPV positive predictive value, NPV negative predictive value, LR likelihood ratio