The classical method of assuring that a load of medical instruments and devices is in fact sterile, after being treated by the sterilizer, is to include a biological indicator (BI). The BI contains a bacterial species deemed difficult to kill by the particular sterilization method employed. The BI is removed after the sterilization cycle, and is cultured to test the cycle. Most BI's require 48 hours for the results to develop.
Best hospital practices, in fact, will specify that the load should not be released until the results of the BI are available.
An alternative is to employ parametric release.
Parametric release is a mechanism for the release of sterilized products to user departments based on the measurement of physical sterilization process parameters in fully validated equipment. It is a broad term used in health care to describes processes which are so well controlled that it becomes possible to release devices immediately after the sterilization cycle, without using biological indicators or end-product sterility testing.
Numerous American and international standards cover best practices for steam and ethylene oxide sterilization (used for heat-sensitive devices), and include the matter of parametric release.
However, few if any hospitals run validated sterilization cycles for steam or ethylene oxide sterilization, since specialized sensors are required, which are more common in so-called "industrial" i.e. large-scale sterilization facilities. That is to say--few if any hospitals use parametric release for steam or ethylene oxide sterilization.
Here's the problem: Another method of sterilization, now deployed in thousands of hospitals, utilizes hydrogen peroxide gas plasma. It has been touted as essentially a replacement for ethylene oxide, and boasts a much faster cycle time.
But, the faster cycle time would be of no benefit if the loads were released on BI, since that would render them no faster--in a practical sense--than ethylene oxide. Thus, many hospitals are releasing the plasma loads parametrically. Unfortunately, no standard exists to validate this process.
Although criteria for a parametric release have been published, this does not constitute a recognized third-party standard. Moreover, the manufacturer has stated that "It is always the hospital's responsibility and decision to implement parametric release."
Does this mean that the hospitals are using patients as the biological indicators?