Principles of Sterility – Principles 10, 11, 12 and 13
Principle Number 10: Sterile persons keep in contact with sterile areas to minimum.
Inside the operating room or within a sterile field the following are strictly observed:
- Sterile persons avoid leaning over sterile tables or drapes.
- Sterile personnel who lean over or sit on an unsterile area is considered contaminated.
Principle Number 11: Unsterile persons avoid sterile areas
- Unsterile personnel should have the knowledge on the proximity to the sterile field. They must be aware of their distance to the sterile area or field to prevent contamination. A distance of at least 1 foot or 30 cm from a sterile field should be maintained and observed by the unsterile staff.
- Unlike the sterile persons who turn their back towards the unsterile surface, unsterile personnel (circulator) face the sterile area (within 1 foot) when passing by to observe and maintain the distance and to avoid touching any sterile objects.
- All activity of a circulator should be kept to a minimum.
Principle Number 12: Destruction of integrity of microbial barriers result in contamination
A sterile package’s integrity is destroyed by the following instances:
- Strike-through – soaking of moisture through unsterile or sterile layers or vice versa.
Before opening a sterile package to be used in a certain procedure or operation the package should be checked thoroughly before opening. The following principles should also be employed in handling packages:
- To prevent strike-through all sterile packages should be placed on a dry surface.
- If any part of the package becomes damp or wet it is considered unsterile and should be discarded or re-sterilized.
- Tables used for operation should be dried before draped.
- If the sterile drape is soaked with a solution the wet area should be covered with an impermeable sterile towels or drape.
- Sterile items should be placed not only in clean but also in dry areas.
- In handling sterile packages, the hands should be dried first.
- Air can also cause contamination. Thus, undue pressure on sterile packs should be avoided. This prevents the ejection of sterile air and the entry of unsterile air into the pack.
Principle Number 13: Microorganisms must be kept to irreducible minimum
Sterilization is the process of removing ALL microorganisms including the bacterial spores. However, not all things or area can be sterilized. The following principles are employed to employ sterile technique in:
Skin cannot be sterilized thus, it can be very good source of contamination in any operation. To prevent entrance of microorganism to the patient’s wound the following are done:
- Surgical hand washing
- Chemical antisepsis of the skin around the surgical site
- Gowning and gloving
- Application of sterile draping.
Air contains dust, droplets and shedding that may cause contamination. Environmental control measures include:
- Movement around the sterile field is kept to a minimum.
- Drapes are not flipped and fanned to avoid the spread of dusts.
- Talking inside the operating room is kept to a minimum because moisture droplets are expelled with force into the mask when a person is talking.