Table 1.

Sensitivity, specificity, positive, and negative predictive values for SDNN.^a

SDNN (ms)	Time (h)	Sensitivity	Specificity	PPV	NPV	Youden’s
<100	0	0.18	0.40	0.40	0.18
	5	1	0.4	0.79	1	0.4
	10	1	0.2	0.73	1	0.2
	15	1	0	0.69	–	0
	20	1	0.2	0.73	1	0.2
<75	0	0.09	0.8	0.5	0.29
	5	1	0.4	0.79	1	0.4
	10	0.91	0.4	0.77	0.67	0.31
	15	0.91	0.6	0.83	0.75	0.51
	20	0.91	0.4	0.77	0.67	0.31
<50	0	0	0.8	0	0.27
	5	0.82	0.8	0.9	0.67	0.61
	10	0.82	1	1	0.71	0.82
	15	0.82	1	1	0.71	0.82
	20	0.82	1	1	0.71	0.82
<25	0	0	1	–	0.31	0
	5	0.09	1	1	0.33	0.09
	10	0.27	1	1	0.38	0.27
	15	0.55	1	1	0.5	0.55
	20	0.55	1	1	0.5	0.55

PPV: positive predictive value; NPV: negative predictive value; Youden’s: Youden’s index.

^aSensitivity, specificity, positive and negative predictive values, and Youden’s index were calculated for several cut-off values of SDNN at times of 0, 5, 10, 15, and 20 h after induction of peritonitis.