Advanced Instrument Processing Solutions

In September 2011 I received this question from a SPD Tech. in reference to an approved value for the amount of residual soil on surgical instruments by the FDA. My answer was that the US FDA had no approved value number. Although this may be true for hospitals and ASC’s, I was recently informed that there is an FDA approved value for residual proteinaceous soil on surgical instrumentation . This FDA standard is for third party Single Use Device reprocessors and it set at less than six point four micrograms of protein per square centimeter (<6.4µg protein/cm²).

Although I had heard this value before in reference to the cleaning of flexible endoscopes (Alfa et al. 2002) as the average soil marker for biopsy/suction channel of clean flexible endoscopes, I did not know that this value had been set as the FDA standard for SUD reprocessors.

This value is also the basis of cleaning verification tests for flexible endoscopes (eg. Healthmarks ChannelCheck™ ). Who knows, maybe one day this verification value will apply to all surgical instruments processed in Healthcare facilities and not just the SUD Reprocessors it applies to now?…only time can tell.

There are multiple and varied substances that can cause the
inflammation of Toxic Anterior Segment Syndrome, but in the case of intraocular
surgical instruments the cause is most likely debris left from inadequate
cleaning, residues from improperly dosed or rinsed cleaning chemistries,
endotoxins from manual soak or ultrasonic cleaning chambers, lint from towels
used to protect instruments or trays, and inorganic salts deposited from the
steam in your sterilizer.

First I would like to suggest that you obtain a copy of the
“Recommended Practices for Cleaning and Sterilizing of Intraocular Surgical
Instruments” from the American Society of Cataract and Refractive Surgery and
the American Society of Ophthalmic Registered Nurses and familiarize yourself
with it.

That being said let me begin with saying that the care of
these (and any other surgical instrument for that matter) begins at the point
of use, keeping instruments free of debris and moist, with sterile, distilled
or de-ionized, water during the procedure will help insure your technicians
will be able to clean and sterilize them properly when the procedure is
finished. Also the sooner the instruments are decontaminated, once the
procedure is finished, the easier they will be to clean. Since Ophthalmic
Viscosurgical Device Solutions can harden in minutes, I would suggest the use
of disposable cannulas and tubing whenever possible. Any non-disposable
cannulas (or instruments) that come in contact with these solutions should be
flushed and keep moist with copious amounts of sterile water to prevent deposits.

Once the instruments arrive in decontamination cleaning
should begin immediately. Always follow the instrument manufacturers IFU when
it comes to cleaning these instruments. If enzymatic detergents are
contraindicated for cleaning, do not use them, if they can be used, I would
suggest using a neutral pH enzymatic detergent that is both color and fragrance
free (please see my answer to the question “We prefer an enzymatic detergent
with coloring and fragrance…” for further discussion on this matter). Always
follow the detergent manufacturers IFU, when it comes to the dosing of their
detergent in solution for cleaning. If you have an ultrasonic cleaner, only use
it with those instruments that can be cleaned in it.

When it comes to the cleaning of ophthalmic instruments, it
is highly recommended, weather in the manual soak sink or ultrasonic cleaner,
that you change the cleaning solution between each tray, to avoid the deposit
of debris from previous trays on instruments. Also more frequent cleaning and
disinfection of the chamber of your ultrasonic cleaner and soak sink is highly
recommended to prevent the build-up of bacterial endotoxins which can deposit
on instruments.

Once the instruments have been cleaned with detergent,
rinse them with copious amounts of water to remove any detergent residue, tap
water may be used here unless contraindicated by either the equipment or
detergent manufacturer. This should be followed by a final rinse with sterile,
distilled or de-ionized, water. This rinse should provide flow over and through
the instruments. The final rinse water should not be reused and agitation of
instruments in a basin of sterile water should not be used since any debris
could redeposit this way.

Following the final rinse all lumened instruments should be
dried with medical grade compressed air.

When assembling instrument sets, closely inspect all
instruments for defects or debris, a lighted magnifying glass is highly
recommended here. If you normally use huck-towels to line your instrument sets,
please make sure that they are both lint and detergent residue free. Call your
linen provider to find out what chemistry is used to wash these towels because
a highly alkaline detergent may transfer chemicals from the towels to the
instruments during sterilization, I have even seen the dye from new huck-towels
transfer to trays so find out from your linen supplier if they have ever had
any incidence with this problem.  A
better choice for tray liners are the specially made disposable dye and residue
free paper liners you can get from many sterilization supply companies.

Since dissolved
inorganic salts in the steam of your autoclave can deposit on your instruments
and my trigger inflammation, have the quality of your steam checked, at least
on a yearly basis.

Yes, there is a BIG DIFFERENCE between the two tests!

What you are using is actually called a Browne STF load-check: this test consists of polysaccharides (sugars), protein and lipids, derived from eggs and porcine (pork), that are printed on a plastic strip. This plastic strip is placed in an L shaped perforated metal holder prior to washer testing.

The TOSI test (Test Object Surgical Instrument) is composed of purified bovine (beef) proteins, haemoglobin, and blood fibrin layered on a stainless steel plate. Furthermore, the metal plate has been scratched to replicate the surface of surgical instruments and covered with a see-thru plastic holder that replicates a box-lock. The plastic holder itself is capable of clipping into a wire sterilization/washer basket prior to washer testing. The producers of this test also make a similar test for washers with lumen cleaning capability.

There are also other tests on the market to verify your cleaning processes. Wash-Check, for instance, consists of proteins mixed with a solvent polymer metered on a metal plate. It has a special holder for placement in the washer that replicates a box-lock. This company also produces a similar lumen cleaning test.

When I mentioned washer verification tests in the past, I reiterated AAMI’s recommendations that washer–disinfector verification tests be performed on a metal coupon since this most closely replicates the surface of surgical instrumentation. Of these tests, AAMI also considers tests composed of “blood test soil” to be the most “valuable as a quality assurance indicator for functionality of a washer-disinfector.”

The ASTM (American Society for Testing and Materials International) also states in their Blood Cleaning Efficiency of Detergents and Washer Disinfectors (ASTM D7225-06), “the regular use of blood soil test is a systemic challenge to the functioning of an automated washer” and recommends these tests be performed on “stainless steel plates.” The ASTM also gives recommendations on what this soil should be composed of. The ATS (artificial test soil) used on TOSI tests is extremely safe: yes it is composed of bovine blood, but this a highly purified product so there is no fear of “catching anything.”

During my years of working in Sterile Processing, it has been my experience that most of the soils I cleaned off instruments in “decontam” were blood based. Rarely, if ever, did I see sugar and eggs on a Finochetto retractor! Moreover, the majority of the instruments placed in the washer-disinfector were made of stainless steel. Since blood is the major source of soil on surgical instruments (and most often it is coagulated and dried on stainless steel), it poses the greatest challenge in cleaning. I believe it only makes sense that we challenge the cleaning efficacy of our washers with the same soil substances and under the same conditions.

The other thing to remember is this: these tests are not made for specific washers; rather, they are made for testing ALL washers and made to challenge the efficacy of YOUR wash cycle. If a test doesn’t pass, it is not because it is too difficult for your washer to clean. Instead, it means the washer needs to be checked! There could be multiple reasons why. For example, a spray arm could be blocked and not turning, or the wash cycle water temperature is too high or low. Perhaps the machine is not dosing the correct amount of detergent to get the job done, etc. The list goes on and on.

What we all need to remember is this: the primary reason for testing washer-disinfectors is the fact that it is a replicable cleaning process that needs to perform correctly every time it is used.

So ask yourself: why wouldn’t you want a test that replicates the worst case scenario in your washer?

At present, there are no quantitative limits of residual protein on surgical instrumentation after decontamination in the United States. Both AAMI ST79 and ISO15883-1 identify “clean” as “the removal of contamination from an item to the extent necessary for its further processing and its intended subsequent use;” however, to this date in the United States, this has been interpreted as “visually clean.”

Recent publications* have demonstrated that even “visually clean” instruments are still capable of harboring unseen protein, lipid and carbohydrate soils. The average residual protein contamination of visually clean instruments in the Baxter study was 380µg. Because of studies like these, and the risks of vCJD transmission, two European nations (Germany and Austria) have begun to set limits of proteinaceous soil on instrumentation.

Germany (DGSV, DGKH, AKI)                             Austria (ÖGSV)
100µg per Instrument                                           50µg per Instrument
20µg per Opthalmic Instrument

As for the testing frequency of instruments or the method presently used to measure residuals in these countries, there is no definitive answer.

I myself recently posed this question of residual protein limits on surgical instruments at an FDA meeting on instrument reprocessing, and I also received no definitive answer.

 
*Publications:

1. Baxter RL, Baxter HC, Campbell GA, Grant K, Jones A, Richardson P, et al. Quantitative analysis of residual protein contamination on reprocessed surgical instruments. J Hosp Infect 2006;63(4):439-44.
2. Alfa MJ et al., Cleaning efficacy of medical device washers in North American healthcare facilities, J Hosp Infect 2009, doi:10.1016/j.jhin.2009.06.030)