Infection Control Today - 07/2000: Event-Related Sterility: Then and Now

July 1, 2000

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Event-Related Sterility: Then and Now

by Connie Cutler, RN, MS, CIC

Storing sterile packs.

Did you ever hear the one about sterile items discovered 50 years after World War II?
The story goes that a nurse found gauze and bandages wrapped in muslin in the basement of
a hospital in British Columbia, Canada. The finder surmised that they were probably
prepared for shipment to Europe. She took them to the laboratory for testing, and cultures
showed no growth.1

Ever since I started in Infection Control almost 20 years ago, I wanted to use event-
related sterilization as the method to determine the conditions under which an item is
considered to be no longer sterile. It never made clinical sense to pick a magical date
after which items would no longer be considered sterile. Illinois finally got the legal
ability to change to event- related sterilization. However, this change did not come
easily. Many articles were written supporting this procedure, but the Illinois Hospital
Licensing Act only allowed date-related sterilization. When it was time for biannual (at
that time) Joint Commission on the Accreditation of Healthcare Organizations surveys, the
nurse surveyor would asked why we weren't using event-related sterilization. I had to
respond that state law did not allow it. She advised that we try to change the law. That
is easier said than done.

Then, in 1994, I was selected to be on a task force of Infection Control Professionals
whose facilities were members of the Metropolitan Chicago Healthcare Council. This
influential group collects data on hospitals and presents programs on health topics. Our
charge was to make infection control recommendations to the state for incorporation into
the Hospital Licensing Act. This panel's members reviewed the literature on the topic and
proposed the change to include event-related sterilization as an additional option. In
1995, the state changed the Hospital Licensing Act to allow hospitals the choice to use
traditional time-dated or event-related sterilization. The new wording is as follows:

Designation of shelf-life may be event related if policies and procedures, approved
by the Infection Control Committee, address at least the following:

  • Requirements for wrapping, storage, and rotation of sterile supplies.
  • Definition of an event that may cause a sterile item to be suspected of being
    compromised, such as the package being wet or torn, or the seal being broken or tampered
  • Clear direction that final inspection of the package and the ultimate decision to use
    the contents of the package rest with the clinician.
  • Orientation, in-service, and other follow-up to assure that all necessary staff
    understand and implement the policies and procedures.2

Many articles promote the safety of event-related sterility. In 1984, one author stated
that time-related sterility was archaic.3 An article published in March 1991
described the institution of successful, documented indefinite shelf-life at two
hospitals. The first was successful in implementing the change by performing cultures of
previously overlooked outdated items from earlier years. These items were cultured and the
results indicated no growth. The second facility also used culturing of expiration dated
items to convince their Infection Control Committee to change its policy. Both facilities
clearly defined the events that could cause loss of sterility and educated the users on
these. Those conditions included that the package is not "torn, wet or damaged or
suspected of being compromised."4 In other articles, cultures of items
also showed no growth.5-6

Savings derive from decreases in labor costs in Central Processing and
Operating Room.

A hospital in Milwaukee reported using event-related sterilization as a continuous
quality assurance process. This reference concluded that "event-related sterility
assurance improves the quality and efficiency of the sterilization process, utilizes fewer
resources, assists in inventory control and related costs, increases staff time for
patient care, and raises employee morale."7 Another author pointed out
that removing items for sterilization after the expiration date had been passed took
sterile instruments out of circulation when they could have been used for patient care.8
In this day of decreasing healthcare reimbursement, purchasing extra instruments to allow
for resterilization of sterile instruments just doesn't make sense.

What type of wrapper is best for event-related sterilization? In an article about
long-term storage effects, Klapes addressed the type of wrapper that would have the lowest
contamination rate. The differences between four types (peel pouches, two two-ply new
reusable non-barriers, two nonwoven barriers, and two two-ply used reusable non-barriers)
was not statistically significant in a storage period of 50 weeks.9 In another
article, Belkin concluded that "a perfect wrapper would be one that is impervious to
extraneous microbes, liquid-proof, free of holes, free of lint, free of memory, strong
enough to resist punctures and tears, and economical to use."10 Unfortunately,
such a product would not allow steam to penetrate for sterilization.

In this era of managed care contracts, any opportunity for cost-savings is appreciated
by administration. The estimated savings from using event-related sterility procedures
ranged from $2,000 per year in 1990 to $10,000 per year in 1992. Savings derive from
decreases in labor costs in Central Processing and Operating Room, decreased laundry
costs, fewer sterilization loads, and fewer supplies such as pouches.1 Other
cost analyses have shown similar results.5 Another facility estimated a $10,000
savings in 1995 in a hospital performing 600 cases/month without including costs of staff
time in "gathering, re-wrapping, reprocessing and reshelving the items."6
Another article quoted savings up to $25,000.11

Obstacles to Implementing Event-Related Sterilization

What obstacles have facilities faced when proposing the change to event-related
sterilization? One author lists the following 10 challenges:

1. Overcoming resistance to change.

2. It takes too much time and effort to change.

3. How to work with state or local laws that still require expiration dates on hospital

4. The hospital isn't comfortable with its storage practices.

5. Gaining control over transportation and handling procedures.

6. Uncertainty about whether packaging material will hold up in event-related sterility

7. Fear of problems with the Joint Commission.

8. Writing a policy takes time and knowledge about the new system.

9. Establishing an effective labeling system.

10. Uncertainty about how long it will take to convert to an event- related sterility
maintenance program.11

In conclusion, Advocate Health Care (Oak Brook, Ill) faced many of the above issues and
came out with a workable event-related sterility program. With a little time, a little
patience, and a little science thrown in for good measure, other facilities can create
similar programs. Be a champion for cost savings at your institution by implementing
event-related sterilization.

Connie Cutler, RN, MS, CIC, is the Coordinator of Infection Control at Advocate
Health Care (
Oak Brook, Ill) and Manager of Epidemiology and Infection Control at
Advocate Lutheran General Hospital (Park Ridge, Ill).


1 Small D. A timeless tale: converting from date-related to
event-related resterilization of supplies. Leadership in Health Services.

2 Illinois Administrative Code. Hospital Licensing Requirements.
1995;Section 250.1090.

3 Mayworm D. Sterile shelf life and expiration dating. J Hosp Supply,
Processing, Distribution.

4 Donovan A, Turner DW, Smith A. Successful, documented studies favoring
indefinite shelf life. Mater Manag Health Care. 1991;9(2):34-40.

5 Schroeter K. Two studies of event-related sterility. Materials Manage.

6 Lamb J, Foster S, Henderson E. Significant savings achieved by
implementing event related outdating. 1996;14(3):12-14.

7 O'Connor LM. Event-related sterility assurance. Surg Technologist.

8 Bell MA. Hospital uses team approach to improve processes, reduce costs. AORN

9 Klapes NA, Greene VW, Langholz AC, Hunstiger, C. Effect of long-term
storage on sterile status of devices in surgical packs. 1987;8(7):289-293.

10 Belkin NL. Should shelf-life policy be determined by events or time? Today's
Surg Nurse.

11 Morrall K. Ten challenges to event-related sterility programs. Materials

For a complete list of references click here