Efficacy of subcutaneous penrose drains for surgical site infections in colorectal surgery

Table 1 Demographic characteristics of the patients in the two periods

	Prior period (n = 131)	Latter period (n = 151)	P value
Age (yr, mean ± SD)	62.7 ± 10.4	63.0 ± 12.4	0.847
Sex (male/female)	68/63	91/60	0.158
Diabetes mellitus (yes/no)	17/114	20/131	0.947
Smoking history (yes/no)	24/107	32/119	0.547
ASA classification (ASA score ≤ 2/3 ≤)	124/7	146/5	0.399
Body mass index (kg/m2)	22.4 ± 3.3	22.5 ± 3.5	0.802
Subcutaneous fat (mm, mean ± SD)	18.2 ± 7.8	19.7 ± 7.1	0.081
Site (colon/rectum)	73/58	95/56	0.220
Operation time (min, median)	206	219	0.864
Blood loss(mL, median)	205	200	0.169
Stoma (yes/no)	32/99	31/120	0.433
Patients with high risk1	40	75	0.001
Patiens with PD	0	151

¹High risk patients whose depth of subcutaneous tissue are over 20 mm. ASA: American Society of Anesthesiologists; PD: Penrose drains.

Table 2 Types of surgery during the two periods

	Prior period (n = 131)		Latter period (n = 151)
	Overall	High risk group	Overall	High risk group
Resection of the colon	73	18	95	46
Resection of the rectum with the stoma	31	10	28	16
Resection of the rectum without the stoma	27	12	28	13
Total	131	40	151	75

Table 3 Demographic characteristics of the high risk patients

	Prior period (n = 40)	Later period (n = 75)	P value
Age (yr, mean ± SD)	61.8 ± 9.7	62.5 ± 11.0	0.743
Sex (male/female)	15/25	36/39	0.280
Diabetes mellitus (yes/no)	5/35	10/65	0.899
Smoking history (yes/no)	8/32	15/60	> 0.999
ASA classification (ASA score ≤ 2/3 ≤)	40/0	75/0	> 0.999
Body mass index (kg/m2)	24.2	24	0.767
Site (colon/rectum)	18/22	46/29	0.093
Operation time (min, median)	245	239	0.588
Blood loss (mL, median)	275	205	0.110
Stoma (yes/no)	9/31	18/57	0.857

ASA: American Society of Anesthesiologists.

Table 4 Incidence of superficial surgical site infections during the two periods n (%)

	Prior period (n = 40)	Later period (n = 75)	P value
Patients with s-SSI (high s-SSI risk group)	6/40 (15.0)	6/75 (8.0)	0.242
Patients with s-SSI (low s-SSI risk group)	2/91 (2.2)	2/76 (2.6)	0.855
Patients with s-SSI (overall)	8/131 (6.1)	8/151 (5.3)	0.770

s-SSI: Superficial surgical site infections.

Table 5 Superficial surgical site infections cases in the later period

Case	Age	Sex	ASA	Fat tissue (mm)	s-SSI risk	Operation	Daysof drainage	Culture
1	72	M	2	23	High	Resection of the rectum with the stoma	4	Not done
4	71	F	2	24	High	Resection of the colon	4	Not detected
2	55	M	2	27	High	Resection of the colon	3	Staphylococcus aureus (skin bacteria)
3	73	M	2	27	High	Resection of the colon	3	Enterococcus facium (intestine bacteria)
5	56	F	2	22	High	Resection of the rectum with the stoma	3	Pseudomonus aeruginosa (intestine bacteria)
6	81	F	2	21	High	Resection of the colon	3	Bacteroides fragilis (intestine bacteria)
7	64	M	2	18	Low	Resection of the colon	4	Enterococcus facium (intestine bacteria)
8	62	M	2	16	Low	Resection of the colon	4	Not detected

ASA: American Society of Anesthesiologists; M: Male; F: Female; s-SSI: Superficial surgical site infections.