Sterilization
Sterilization
It is a process which achieves the complete destruction or killing of all microorganisms, including bacterial spores. Sterilization is principally accomplished by:
Steam Under Pressure (Autoclaving)
Steam sterilization is the most common and most preferred method employed for sterilization of all items that penetrate the skin and mucosa if they are heat stable. Steam sterilization is dependable, non toxic, inexpensive, sporicidal, and has rapid heating and good penetration of fabrics. The steam must be applied for a specified time so that the items reach a specified temperature. For unwrapped items:
- 121 °C for 20 min. at 1.036 Bar (15.03 psi) above atmospheric pressure.
- 134 °C for 3-4 minutes at 2.026 Bar (29.41 psi) above atmospheric pressure
Dry Heat (Hot Air Oven)
For dry heat-sterilization to be achieved, a constant supply of electricity is necessary. Dry heat is preferred for reusable glass, metal instruments, oil, ointments and powders. Do not use this method of sterilization for other items, which may melt or burn.
Table 5.2 Sterilization Time With Different Temperature Level
| Holding Temperature | Sterilization Time (After reaching the holding temperature) |
|---|---|
| 180 ºC | 30 minutes |
| 170ºC | 1 hours |
| 160ºC | 2 hours |
| 149ºC | 2.5 hours |
| 141ºC | 3 hours |
| 121ºC | Over night |
Chemical Sterilizer
Before deciding to use a chemical sterilizer, consider whether a more appropriate method is available. Chemical sterilizers are primarily used for heat- labile equipment where single use is not cost effective. Instruments and other items can be sterilized by soaking in a chemical solution followed by rinsing in sterile water. If an item is sterilized chemically, it should be used immediately after sterilization, to be sure that it is sterile.
Instructions on the Use of Chemical Sterilization in Steps
- Decontaminate, clean and dry all instruments and other items to be sterilized using chemical.
- Completely submerge items in a clean container filled with the chemical solution and place the lid on the container.
- Allow items to soak:
- 10 hours in a glutaraldehyde (check specific product instructions), or
- At least 24 hours in 8% formaldehyde.
- Remove objects from the solution with sterile forceps; rinse all surfaces three times in sterile water and air dry. Ideally, three separate (sequential) rinse containers should be used.
- Store objects in a sterile container with a tight-fitting lid if they will not be used immediately
Table 5.3 Key Steps in Processing Contaminated Surgical Instruments
