Hospital Monitoring System for Infection Control

Hospital Monitoring System

The Sterilization procedure must be monitored routinely by a combination of mechanical, chemical and biological parameters. These process parameters evaluate the sterilization conditions and indirectly the microbiological status of the processed items.

1. The mechanical techniques for sterilization include a daily assessment of cycle time and temperature by examining the temperature record chart as well as an assessment of pressure via the pressure gauge (unfortunately, two other essential elements for ETO sterilization (i.e. gas concentration and humidity) cannot be monitored)

2. Chemical Indicators :

• These are indicators that show exposure to sterilization processes by means of physical/ chemical change.
• Chemical indicators are usually paper printed with either heat or chemical sensitive inks that change colour when one or more germicidal related parameters are present.
• They are affixed on the outside of each pack to show that the package has been processed through a sterilization cycle.
• Preferably, a chemical indicator should also be placed on the inside of each pack to verify steam penetration.
• Indicators are designed for one or more than one critical parameters.
• Nowadays integrating indicators are available which are designed to react with all the critical parameters over a specified range of sterilization cycles.
• These very nearly duplicate the function of biological indicators.

3. Biological Indicators :

• Are standardized preparations of specific micro-organisms relatively resistant to the particular sterilization process.
• Are used to demonstrate in a positive manner the adequacy of sterilization process.
• An aliquot (containing about a million spores) of a viable culture of a known species of micro-organism is added to disks, filter papers or any other suitable carrier.
• The disks or strips are placed within the test packs in the sterilization.
• B.subtilis spores (10^6) are used to monitor ETO and dry heat and incubated at 35 to 37 C after process.
• B.stearothermophilus spores (10^5) are used to monitor steam sterilization and incubated at 55 C.
• Steam sterilizers should be monitored at least weekly and ETO with every cycle using the appropriate commercial preparation of spores.
• Each load should be monitored if it contains implantable objects.
• When feasible, do not use implanted items until results of spore tests are known to be negative.

Bowie Dick test

This is the test used to determine that there is complete air removal in pre vacuum sterilizers.

This test is to be done daily

• There will be an even and rapid penetration of steam into the load in a porous load sterilizer only if sufficient air and non condensable gases are removed from the chamber and the load before steam is admitted.
• If air and non condensable gases are not removed from the chamber and the load or from the steam supply, they may not be obtained.
• This test does not confirm that sterilizing conditions have been achieved in the load.

Proves whether or not steam penetration of the pack has been even

• An adhesive tape, which is printed with a chemical substance, is fixed in the shape of a cross to a piece of suitable paper.
• This test sheet is placed in the center of a stack of towels.
• The chemical substance shows a change in colour when exposed to phase boundary steam.
• To obtain optimum colour change for interpretation, the test must not be run for longer than three and a half minutes at 134- 135 degree C.
• The tape will show a uniform colour change if all the air is removed and steam penetrates rapidly and completely. If all air is not removed, then air will collect in the form of a bubble. The colour of the tape in the region of the bubble will be paler than elsewhere because of low temperature or reduced moisture level.