1 Materials and Methods
1.1 Materials The DMQ-0.3 pulsating vacuum pressure sterilizer produced by Jiangsu Lianyungang Medical Instrument Factory was used, and the B-D test paper produced by 3M Company, and the homemade cotton cloth standard package were used.
1.2 Methods The B-D test kit consists of 50 cotton cloth towels 50cm×90cm in size, which are first folded horizontally into 3 layers, and then folded longitudinally to form 6 layers. Folded cloth towel a stack of one to a height of 25cm, stacked, each layer of cloth towel according to the folded side of the left and right alternately placed, so that the thickness of the two sides are equal. After the cloth towel arranged, the chemical indicator chart horizontal clamped between the central layer of cloth towel, and then use the cloth to wrap all the cloth towel into a test package, the outside of the 3M chemical indicator tape is fixed, the size of the entire cloth towel package, height of about 25cm, width of 23cm, length of 27cm, weighing 4kg. The test package will be placed horizontally in an empty pot, close to the door of the cabinet and the exhaust port, in the steam source pressure of 0.30 ~ 0.50MPa Under the condition that the water source pressure is 0.15～0.30MPa, vacuum 3 times to vacuum 0.086MPa, reach the working pressure of 0.21MPa, temperature 134℃, sterilize 3.5～4min, remove and observe the judgment results.
2 Judgment criteria B-D test paper shows black and white lines, color uniformity, clear, indicating rapid penetration of steam, cold air exclusion, no obvious air leakage, no cold air mass exists, indicating that the test is qualified. B-D test paper discoloration is uneven or the middle part of the test paper is lighter than the external color, indicating that the monitoring is unqualified.
3 Discussion Analysis of pulsating vacuum pressure steam sterilizer B-D test failure is mainly due to: (1) the new cotton towel is not washed, there is pulp present, steam is difficult to penetrate; (2) the old cotton towel test is not washed, the cloth and the cloth by the impact of high-heat steam, each other pressed, so that the steam is not easy to penetrate, affecting the release of latent heat, the middle of the test paper pattern of light color [1]; (3) the test package The package is too tight, affecting the steam penetration, pattern black and white line is not clear; (4) insufficient steam pressure, steam pressure less than 0.3MPa; (5) the sterilizer is not enough time to preheat before use, especially in winter, such as preheating time of less than 10min, there will also be the middle part of the pattern color is lighter than the outside; (6) the cloth towel is excessively dry, resulting in cloth towel humidity is too low, the steam enters the sterilization cabinet can not be condensed into water and Release potential, resulting in over-saturation, the pattern is uneven gray [2]; (7) cloth towel is too wet, high-temperature steam into the cabinet room meets the cold wet cloth towel, quickly condensed into water, excess water to the test paper infiltration to form water stains, affecting the heat penetration, the pattern of the white lines of the edges of the yellowish-brown [2]; (8) the failure of the sterilizer, the effect of the vacuum pump decreases, resulting in the cabinet does not reach the proper vacuum Degree; automatic control system failure, shorten the pumping time, seal aging, can not maintain the specified negative pressure, resulting in the exclusion of cold air while still cold air infiltration, affecting the test results [1]. Through the standardization of B-D test kit production, and to do each test after the cloth towel must be washed before use; to avoid cloth towel too dry or too wet; cloth towel packages appropriate elasticity; the failure of the sterilizer, in a timely manner, please ask the professional maintenance personnel for overhaul, sterilizer repair, retesting the B-D test. After finding out the reasons and making improvements, all the 145 B-D tests conducted in 2005 were qualified. Supply room sterilization quality assurance is one of the important measures to prevent hospital infections. The residue of cold air mass inside the pulsating vacuum pressure steam sterilizer will affect the sterilization effect of the sterilizer.B-D test is one of the important indexes to detect whether the pulsating vacuum pressure sterilizer meets the sterilization requirements. Therefore, before autoclaving, the pulsating vacuum pressure (pre-vacuum) sterilizer must be B-D test. Analyze the reasons for the failure of the B-D test, to avoid the failure of the B-D test due to technical factors caused by the waste of manpower, material resources, time and other resources to ensure the reliability of the sterilization effect of the pressure steam sterilizer.