Infection Control Today - 08/2003: Guidelines for Maintaining the Sterile Field

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Guidelines for Maintaining the Sterile Field

By John Roark

Event Related Sterility (ERS) has become a well-accepted standard in the processing of sterile healthcare devices and supplies since the early 1990s. The idea behind ERS is that if a sterile item (packaged according to acceptable protocols) and its packaging have not been compromised, the item is considered to be sterile and safe for use. With ERS, sterile packaged items are assumed to be sterile as long as the package is intact; length of time since sterilization is irrelevant.

The techniques used during processing by manufacturers produce a totally sealed package made of impervious materials. Typical ERS package labels read, Contents sterile unless package is open or damaged. Inspect before use.

In any situation, each package of sterile items must be carefully inspected by the end user for any break in integrity regardless of expiration date or event-related processes. Breaks in integrity can include evidence of holes and tears, watermarks that may indicate that the item was wet after sterilization, and defects in peel-pouch seals. Inspection for these breaks is a priority when handling any packaged sterile item or device.1

Establishing a Sterile Field

Rigorous adherence to the principles of asepsis by all scrubbed personnel is the foundation of surgical site infection prevention. Others who work in close proximity to the sterile field must also abide by these principles.

Nonsterile equipment or furniture, such as the Mayo stand, should be covered appropriately with sterile barrier materials if it is to be used during the procedure. Only sterile items should touch or extend over sterile surfaces.

Opening Packs

Sterile drapes establish an aseptic barrier that minimizes the passage of microorganisms between non-sterile and sterile areas.

The drape pack should be placed on a clean, dry surface and unfolded by touching only the outside of the wrapper. The inside of the outer wrapper becomes the table drape and the base of the sterile field. Care must be taken so that the inside or sterile portion of the wrapper does not touch any part of the non-sterile surface.

Inspection for tears, holes or areas of strikethrough should be performed immediately, before additional items are placed on the sterile field. When opened, the edges of the drape are considered non-sterile below the level of the table or other flat surface.

Opening Sterile Items

Before presentation to the sterile field, all sterile items should be inspected for proper packaging, processing, seal, package integrity and the inclusion of a sterilization indicator and expiration date, if indicated.

  • Surgical supplies should be opened only when there is reasonable certainty that they will be used during the procedure.
  • Items that are introduced into the sterile field must be sterile and remain sterile until they are used. Secure packaging, sterilization, delivery to the field and handling during use should provide that assurance.
  • Items introduced onto a sterile field should be opened, dispensed and transferred by methods that maintain sterility and integrity.
  • Some sterile items (e.g., suture packages) are designed to be flipped onto the sterile field. The inner edge of the seal of the peel package is considered the sterile boundary. With instruction and practice, items can be safely flipped onto the sterile field without contaminating the field by reaching over it.

Sterile Storage

The Association of periOperative Registered Nurses (AORN) recommends that access to the sterile storage area should be limited and separated from high-traffic areas. Sterile supplies should be stored separately from clean supplies. Sterile materials may be stored in either open or closed shelving that is at least eight to 10 inches from the floor, at least 18 inches from the ceiling, and at least two inches from outside walls.

When open shelving is used, a solid shelf or tote box should be used on the bottom shelf to create a barrier between the floor and the bottom shelf. The temperature of the area should be controlled between 65 to 72 degrees F (18 to 22 degrees C) with humidity maintained between 35 and 50 percent.

If clean and sterile supplies must be stored within the same cupboard or shelving unit, the sterile items should be stored on the upper shelves above the clean items. Storing sterile items above clean items reduces the risk of lint, dust, and other debris falling from clean items onto the sterile items. Neither clean nor sterile supplies should be stored next to or under sinks, exposed water or sewer pipes, or in locations where they can become wet.2

Dropped Items

If a sterile package is dropped, the item may be considered safe for immediate use only if it is enclosed in impervious packaging that was not punctured or torn on impact. If the wrapper is impervious and the area of contact is dry, the item may be transferred to the sterile field. Dropped items wrapped in reusable woven fabric materials should not be transferred to the sterile field because these materials allow air to implode into the package.

A dropped package should not be put back into sterile storage.

Traffic Patterns

Surgical suites and traffic patterns are designed to facilitate movement of patients and personnel into, through and out of defined areas within the surgical suite. Increasing environmental controls and the use of additional surgical attire as the progression is made from unrestricted to restricted areas decreases the potential for cross-contamination. Signs should be posted that clearly indicate the appropriate environmental controls and surgical attire required. All persons (staff, patients and visitors) should follow the delineated patterns in appropriate attire.

There are at least 15 air changes per hour, which is code for a garden-variety OR, says Barbara Gruendemann, RN, MS, FAAN, CNOR, co-author of Infection Prevention in Surgical Settings.When you have positive-pressure rooms, every time you open the doors to the OR, to some extent it will disrupt those airflow currents. Doors should be kept closed as much as possible during the procedure after the patient is wheeled into the room because we know that there are some potentially infectious agents that are propelled through the air. The more you open and close the doors to the room, the more airborne contamination you will get. She continues, Even though the degree to which airborne contaminants contribute to surgical site infection is unknown, we do know that it has some influence. I think thats the most common mistake involving traffic patterns opening and closing doors. It should be kept to an absolute minimum.

Researchers believe that the OR environment, including the people involved in a surgical procedure and the existing traffic patterns, is a major source of contamination that increases both with movement and talking. AORNs Recommended Practices for Traffic Patterns in the Surgical Suite, is designed to reduce the amount of airborne contamination during surgery. AORN recommends that movement of staff members should be kept to a minimum while a surgical procedure is in progress. This includes minimizing the number of people in the OR, movement, and talking during surgery and maintaining that the OR doors be closed except during movement of staff members or equipment. AORN reasons that:

  • Greater amounts of airborne contamination can be expected with increased movement
  • The mixing of OR air with corridor air increases the bacterial count in the room
  • Shedding increases with activity.3

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