1. Methods of Sterilization

1. Physical Methods

1. Steam Thermal - Autoclave

1. Definition -- a self-locking apparatus for the sterilization of material by means of steam under pressure.

2. Settings for general wrapped items:

Temp. - 250^oF    Pressure - 20 PSI

Time -- 30 min    Setting -- Fast Exhaust & Dry

3. Settings for bottled solutions:

Always vent bottles to avoid bursting!

Temp. - 250^oF     Pressure - 20 PSI

Time -- 30 min    Setting -- Slow Exhaust

4. Setting for "Flashing" an unwrapped instrument:

Temp. - 270^oF     Pressure - 30 PSI

Time -- 4-7 Min   Setting -- Fast Exhaust

5. Notes -- The above are general steam autoclave settings.  Different models may operate with varying settings.  Always refer to the appliance literature before operating a new piece of equipment.

2. Radiation

1. Use on materials that cannot be sterilized by heat or chemicals

2. Radiant energy destroys microorganisms

3. Filtration -- is a method utilizing filters capable of screening out microorganisms

2. Chemical Methods 

1. Ethylene Oxide Gas

1. Colorless gas at room temperature

2. Odor similar to ether

3. Very toxic and irritating to skin and mucous membranes

4. Microorganism destruction is caused by a chemical reaction

5. Materials sterilized need to be aerated in well ventilated room or placed in an aerator.  Length of time required depends on  items sterilized. 

6. Effective sterilization is dependent on concentration of gas, exposure time, temperature, and relative humidity

7. Hazardous chemical, use great care

2. Cold Sterilization

1. Instruments should be completely dry before soaking to prevent dilution

2. Instrument soaking solution - 10-20 minute emersion only disinfects

3. Incomplete destruction of spores, unless soak is for 10 hours

4. Examples:  Instrument Germicide (Phenol and Ethyl alcohol), Cidex^TM  (Glutaraldehyde)

5. Most require thorough rinsing before using instrument

6. Contact time required varies with product used

2. Sterilization Shelf Life of Packaged Supplies

1. The following wrapped items, if carefully maintained, are sterile for up to one (1) month:

1. Double cloth wrapped instruments

2. Double paper wrapped instruments

3. Inexpensive peel pouches for gauze sponges

4. Nalgene^R saline bottles

2. Two (2) packaging methods are sterile for up to six (6) months:

1. Monarch^R Instrument Canisters  --  Special box system with single use filters for use in steam autoclaves

2. Sterility  Maintenance  Covers  --  Sealable  plastic covers to place over freshly autoclaved and cooled packs to extend shelf life by diminishing air penetration

3. Heat sealed packages commercially prepared in tube or peel pouch form may be considered sterile for up to one (1) year.

3. Sterility Check List

Before assuming a pack is sterile, always evaluate the following before opening the pack:

1. Expiration or sterilization date

2. Indicator color change

3. General condition of wrapper and how it had been stored

4. Always check for holes or moisture damage