Table 2. The Classification of Surgical Site Infection.

	Before matching			After matching
	Volatile (n = 1519)	Propofol (n = 415)	P value	Volatile (n = 390)	Propofol (n = 390)	P value
No SSI	1481 (97.5%)	413 (99.5%)	0.004	380 (97.4%)	388 (99.5%)	0.039
SSI	38 (2.5%)	2 (0.5%)	0.084*	10 (2.6%)	2 (0.5%)	0.180*
Superficial SSI	20 (1.3%)	1 (0.2%)		4 (1.0%)	1 (0.3%)
Deep SSI	14 (0.9%)	1 (0.2%)		5 (1.0%)	1 (0.3 %)
Organ/space SSI	4 (0.3%)	0 (0.0%)		1 (0.3%)	0 (0.0%)

Data are Presented as Number (%). SSI: surgical site infection. ^*The P value among 4 categories, No SSI, superficial SSI, deep SSI, organ/space SSI.