Table 1.

Key characteristics of the meta-analyzed reports (n = 18).

Index test	Author	Year	Country	Ref.	Cutoff value	TP	FP	FN	TN
BNP1	Armand	2006	France	[10]	275 pg/ml	35	7	6	54
	Xu	2013	China	[44]	263 pg/ml	10	13	2	41
	Xing	2014	China	[42]	849.1 pg/ml	26	9	8	80
	Zhou	2013	China	[46]	204 pg/ml	13	3	3	25
	Ma	2016	China	[40]	294.79 pg/ml	15	10	3	42
	He	2013	China	[45]	139 pg/ml	12	4	5	15
	Total					111	46	27	257
BNP2	He	2013	China	[45]	157 pg/ml	13	4	4	15
	Xing	2014	China	[43]	224.5 pg/ml	40	15	10	93
	Ma	2016	China	[40]	332.95 pg/ml	16	6	2	46
	Shereen	2014	Egypt	[33]	164 pg/ml	9	6	5	10
	Lara	2013	Brazil	[37]	299 pg/ml	11	11	1	78
	Total					89	42	22	242
ΔBNP	Cheng	2015	China	[34]	80 pg/ml	31	12	2	11
	Yang	2011	China	[38]	123 pg/ml	64	1	6	12
	He	2013	China	[45]	29 pg/ml	13	1	6	16
	Ma	2016	China	[40]	69.36 pg/ml	48	2	4	16
	Zhang	2012	China	[47]	46 pg/ml	44	2	2	10
	Total					200	18	20	65
ΔBNP%	Cheng	2015	China	[34]	13.4%	28	4	5	19
	Chien	2008	China	[19]	20%	65	4	6	26
	Sameh	2014	Egypt	[35]	20%	23	2	2	13
	Shereen	2014	Egypt	[33]	14.9%	13	5	3	9
	Total					129	15	16	67
NT-proBNP1	Hu	2010	China	[48]	3635.5 pg/ml	41	16	13	90
	Li	2016	China	[39]	715.5 pg/ml	14	7	1	20
	Total					55	23	14	110
NT-proBNP2	Gang	2013	China	[36]	448 pg/ml	6	7	1	15
	Wen	2015	China	[41]	1199 pg/ml	26	4	8	79
	Total					32	11	9	94

BNP1, BNP levels were measured before the preparation of SBT and the prediction of weaning failure. BNP2, BNP levels were measured at the end of SBT and the prediction of weaning failure.

ΔBNP, the change of BNP levels before and after SBT and the prediction of weaning success.

ΔBNP%, ΔBNP divided by BNP1 and the prediction of weaning success.

NT-proBNP1, NT-pro BNP levels were measured before the preparation of SBT and the prediction of weaning failure. NT-proBNP2, NT-pro BNP levels were measured at the end of the SBT and the prediction of weaning failure.

TP: true positive; FP: false positive; FN: false negative; TN: true negative.