Using vaporized hydrogen peroxide for anhydrous disinfection of gastrointestinal endoscopes

Table 1 Laboratory disinfection efficacy of vaporized hydrogen peroxide

Disinfection time (minutes)	Total	Unqualified	Qualified	Average CFUs of the positive control group (CFU/bacterial carrier)
10	8	8	0	4.8 × 106
20	8	2	6	4.5 × 106
30	8	0	8	4.7 × 106

CFU: Colony-forming unit.

Table 2 Vaporized hydrogen peroxide treatment dosages with different concentrations and disinfection times

Concentration of VHP (mg/L)	Disinfection time (minute)	Exposure dosage (mg/L/hour)
72	20	24
90	20	30
72	30	36
90	30	45

VHP: Vaporized hydrogen peroxide.

Table 3 Numbers of colonies counted from each sampling location of the disposable endoscopes before and after disinfection via vaporized hydrogen peroxide

No.	Number of colonies (CFU/item)
	Biopsy channel		Biopsy valve		Endoscope surface		Suction channel
	BD	AD	BD	AD	BD	AD	BD	AD
1	10	0	0	0	10	0	19	0
2	40	0	0	0	0	0	24	0
3	140	0	38	0	7	0	6	0
4	30	0	12	0	11	0	0	0
5	10	0	12	0	0	0	0	0
6	20	0	0	0	0	0	0	0
7	10	0	0	0	0	0	0	0
8	100	0	18	0	42	0	102	0
9	20	0	25	0	0	0	58	0
10	80	0	12	0	18	0	7	0

CFU: Colony-forming unit; BD: Before disinfection; AD: After disinfection.

Table 4 Comparison of the high-level disinfection effects of the two methods on gastrointestinal endoscopes, n (%)

Group	Gastroscope (n = 40)	Colonoscopy (n = 40)	Duodenoscopy (n = 40)	All endoscopes (n = 120)
Experimental group	19 (95)	18 (90)	18 (90)	55 (91.6)
Control group	20 (100)	20 (100)	20 (100)	60 (100)
χ2	0.000	0.526	0.526	3.339
P value	1.000	0.468	0.468	0.068

Table 5 Comparison of the sterilization effects of the two methods on gastrointestinal endoscopes, n (%)

Group	Gastroscope (n = 40)	Colonoscopy (n = 40)	Duodenoscopy (n = 40)	All endoscopes (n = 120)
Experimental group	15 (75)	10 (50)	10 (50)	35 (58.3)
Control group	11 (55)	13 (65)	13 (65)	37 (61.7)
χ2	1.758	0.921	0.921	0.198
P value	0.185	0.337	0.337	0.656