1

The Short Story onLong Cycles

Why the length of your steam sterilization cycle may effect your sterility assurance

2

A Canadian Standard Cycle?

• CSA does not recognize a standard steam cycle length

• Most common pre-vacuum cycle in Canada is a 4 minute exposure at 132-134oC

• Scientific evidence that 2 minutes of exposure kills highly resistant bacterial spores (Geobacillus stearothermophillus)

3

Who Determines Cycle Length?• CSA-Z17664-06 (Sterilization of medical devices) states:

“This standard specifies requirements for the information to be provided by the medical device manufacturer, so that the medical device can be processed safely and will continue to meet its performance specification. Requirements are specified for processing that consists of all or some of the following activities:

– preparation at the point of use;– preparation, cleaning, disinfection;– drying;– inspection, maintenance and testing;– packaging;– sterilization;– storage.”

4

Why Longer Cycles?

• Increased weight, density and complexity of instrument trays (particularly for orthopedic instrument sets)

• European validation studies at cycles that are not typical in North America (i.e. 8 min, 10 min, 12 min, 15 min, 18 min or longer!)

5

What is the Problem?

• Extended cycles lead to decreased throughput in the department (partial loads and longer flow times)

• Frequent changing of sterilizer cycles may lead to

errors

• More information required for the processing staff to remember

• CSA Standards require chemical and biological monitoring of steam sterilizer cycles, but current monitoring devices are intended for use in 4 minute cycles

6

Performance Validation

• If the monitoring devices fails to function normally in extended cycles, the results cannot be trusted

• Potential for false positives and false negatives

• Will your chemical indicators delaminate? Is the growth media in your BI able to support normal growth after exposure to an extended cycle? Has the manufacturer validated this information?

7

What is Being Done?

• AAMI/CSA are considering establishment of 2-3 standard cycle lengths (i.e. 4 min, 10 min, and 20 min)

• Medical device manufactures re-validating their products for 4 minute cycles

• Hospitals are breaking down heavy and complex sets to allow sterilization in 4 minutes (with manufacturer validation)

8

What Shouldn’t be Done

• Run 4 minute cycles for devices requiring longer cycles and assume (hope!) that sterilization has occurred

• Attempt in-house validation of

sterility at 4 minutes - hospitals do not have the facilities to make this confirmation

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Recommended Steps

1. Standardize to two or fewer extended cycles (i.e. 10 min and 20 min) and require device manufactures to validate to them.

2. Dedicate one sterilizer to be used for extended cycles, reducing the chance of an error

3. Specify a performance validated test pack for monitoring sterilizer loads with extended cycle• Confirm the validation has been completed by independent

laboratories and follows industry-accepted protocol

4. Require performance validated Class 5 chemical indicators to be placed in the trays in the most challenging locations

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Stay Informed!

• Attend industry association meetings and education seminars

• Read relevant journal articles• Ask questions of your vendors and require

documentation• Don’t accept the status quo!