Advanced Instrument Processing Solutions

The Potomac Labs team is pleased to present commonly asked questions encountered in sterile processing.

Charles Ciullo, our Director of Sterile Processing, is here to answer your questions.

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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.

To verify that your new sterilizer is working properly you need to run three consecutive Biological process challenge devices (a Biological pack containing a class 5 integrating indicator) in a “normal” sterilization cycle, the minimum exposure time, temperature and pressure recommended by the steam sterilizer manufacturer. These need to be run in an empty chamber placed on the sterilization rack over the drain. If this is a dynamic air removal sterilizer (prevac) these need to be followed by three consecutive Bowie-Dick tests.

This is the same test that AAMI recommends you perform on your steam sterilizer after a major repair (ANSI/AAMI ST-79 10.6.4). Normal service of your autoclave that occurs during preventive maintenance, like the replacement of gaskets or the rebuild of a solenoid valve is not a major repair, replacing the whole sterilizer door, vacuum pump, steam generator or weld repairs in the pressure vessel IS, so is rebuilds or upgrades of controls, any major piping assembly work or moving the sterilizer. If you were in a large institution where your steam was supplied by a free standing boiler and that was replaced by a new boiler or new piping was installed from boiler to sterilizer it would also be considered a “major repair”.

If your steam sterilizer is designed to be used for multiple cycles, dynamic-air removal (prevac), gravity displacement, and immediate use (flash) sterilization, then each of these modalities must be run 3 consecutive times each with a Bi PDC test on their minimum cycle followed by 3 Bowie/Dick tests. When all BI’s have been incubated for their given time and there are no positive cultures and the Bowie/Dick Tests have all passed, your sterilizer can  be put in service. So free up some time and incubator space because you have your work cut out for you….and please remember to document everything. GOOD LUCK!

My first suggestion would be to make sure any container system you are investing in is compatible with all the cleaning and sterilization modalities it will be used in. If your facility uses a high alkaline cleaning chemistry you would need to change to a neutral pH detergent to avoid irreversible damage to an anodized aluminum rigid container. If you facility wants to use a rigid container system in a gas/plasma sterilizer (like Sterrad®) make sure that the containers you are purchasing have been validated for use there. If your facility only has a steam sterilizer you will still need to make sure that the containers you are purchasing are compatible with any special cycles that you might run it in, containers that are validated for a pre-vacuum cycle in the autoclave are usually only validated for use in pre-vac, where as those that are validated for use in a gravity displacement cycle are usually also validated for use in pre-vac (these containers are usually also validated for use in EO and gas/plasma sterilizers but please check the container manufacturers validations before using them in these modalities).Because of their versatility, the gravity displacement containers have usually been my container of choice. Whatever system you purchase, the most important thing is that you obtain all the written instructions for use from the containers manufacturer.

Also it is recommended by AAMI (ST-77) that you evaluate one of each size container you will be purchasing with Biological Indicators in your steam sterilizer to verify your sterilizer can achieve sterilization inside the container. This same test should then be repeated annually to verify the process is still working. Unless otherwise specified by the container manufacturer, the biological indicator should be affixed, one in each corner of a full basket of instruments, in a manner that the BI will not touch the metal basket, one more BI should then be suspended from the center of the lid so that it does not touch the instruments in the tray or the metal lid. In total each container being tested will contain 5 BI’s, which all must be from the same lot number, and as with all BI testing, the control must have the same lot number too. Place chemical indicators in two opposite corners, close and lock the container and label it TEST PACK.

You’re not done yet, because there are TWO protocols that the each size containers must be tested under.

Maximum Load Testing – (this is to replicate actual sterilization conditions) ….. Two test containers are prepared and place as close to the drain line as possible, fill the rest of the autoclave shelves with containers and other items.

Small Load Testing – (this replicates “worst case scenario”) …..Place one prepared container BY IT SELF on the sterilization cart/shelf, over the drain line, again no other items but the test container are run in this test load.

After the cycle is complete open the containers, let the BI s cool then incubate them. If all goes well, all of the BI test will be negative.

If you are testing containers for an Ethylene Oxide sterilizer only a small load tests are required, prepare the containers as you would steam sterilization but with the appropriate BI and CI s.

There are currently no tests required for Gas/Plasma sterilizers.

Once your rigid containers pass testing, you’re good to go, but remember to check with the instrument manufacturer before you begin putting all you instruments in rigid containers. Although it is usually a given that all strung instrument sets can be sterilized and stored in a container there are plenty of instruments that according to the manufacturer, can not (e.g. power instruments, implantables, etc…) so please check with the instrument manufacturer before placing these things in a rigid container.

Lastly, the container, like the instruments it contains, MUST BE WASHED after the surgical case is finished, I don’t care how far away from the “field” it was, it is still “dirty” and needs to be cleaned.

By investing in a rigid container system you not only cut down the cost of disposable wrappers, but you produce less waste, a small disposable filter takes up much less landfill space than a disposable wrapper, so they are defiantly a “green” choice.

If you are concerned about the monetary implications of adding
an additional chemistry to your cleaning process, let me start by saying that
the other solutions I am about to give you are more costly and will entail the
investment in additional equipment in your department.

According to the U.S. Geological Survey, over 85% of the
country has hard water, that being said you could soften your water to remove
the dissolved minerals that cause hard water, but by doing so you are just
exchanging the calcium and magnesium (the minerals that make it “hard”) in your
water for sodium, also softening water only removes the positively charged
mineral ions from your water any negatively charged ions remain. Softened water
might be good for your home when it come to cleaning, but I would have to say
that because there are still dissolved minerals, you are still going to have
dissolved minerals depositing on your washer chamber and instruments.

The best choice would be using either De-Ionized or Reverse
Osmosis water in your washer. Both of these water treating systems remove all
positive and negatively charged mineral salts from your water, so the
probability of mineral deposits is very low. Many facilities use D.I or R.O.
water in their final thermal rinse, yet use tap water in the rest of the full
automated cleaning cycle, because this final rinse is being done with water
that is ion free there will be no mineral deposits from it. But what about the
tap water that is being used in the rest of the cleaning cycles? Chances are
that some mineral deposits are forming there.

Many hospitals in Europe now use D.I or R.O. water
throughout the full automated cleaning cycle to eliminate the chance of any
mineral deposits and also to improve the cleaning of their instruments. Please
see my answer to the question   “ Our
hospital has very hard water that leaves deposits on our instruments. Would
water softening help?”  for more
information on this matter.

Finally if you are worried about using an acid neutralizing
rinse because you believe it will leave acid residue on your instrumentation
let me assure you that if the chemistry is dosed properly you will not have any
residual acid on your instruments.

Stainless Steel cleaner is great for cleaning the exterior of your washer, (or polishing your stainless steel refrigerator at home) but it is not a good choice for cleaning the interior wash chamber of the W/D.

Those white deposits on your chamber are from hard water and primarily composed of calcium carbonate (let’s think eggshells or chalk here).

Stainless Steel cleaner, even those that claim to be water based, contain mineral oil and silicone.

So basically when you use a Stainless Steel cleaner on the interior of the washer chamber, you are just coating this calcium carbonate with mineral oil and silicone. It may look good when you are done but after a few wash cycles you will have washed most of this coating away and in the meantime added some more calcium carbonate coating to your washer chamber.

Now let’s think of those eggshells or chalk I mentioned before if you put mixture of mineral oil and silicone on chalk, how easy it that going to be to wash off? It just seeps into the porous chalk and may take a few washes to remove with water and detergent, but where is it going? Into the wash water…do you see where I’m going with this?

Ok, so how do you remove the deposit properly?  Calcium carbonate is a base (alkali) when it comes in contact with an acid there will chemical reaction that will break down this alkali (and weaken the acid too). Try this…next time you are at home making eggs, take a piece of eggshell and put it in a glass with plain white vinegar.  You will begin to see bubbles form on the eggshell, this is the reaction between the acid and the alkali….if you leave the eggshell in the vinegar long enough it will totally break down. You need to reproduce this same chemical reaction in your W/D to remove the deposits. This can be done one of two ways, once a week you can run a de-liming in an otherwise empty full cleaning cycle or you can add an acid rinse to one of the rinse cycles following your detergent wash cycle. If you have any questions on whether or not this will harm your instruments, please see my answer to the question “We only use a neutral pH enzymatic detergent in our facility, why would we want to use an acid rinse in our W/D….?”

One thing I neglected to mention was the fact that if you have these hard water deposits on the W/D chamber walls, there will be deposits on and in the spray arms of your W/D and on the heating element. Deposits here are even more detrimental than on the chamber walls. When deposits form on the holes in the spray arms they become clogged, this eventually impedes both the spray of water out of the arms and their impingement, I have seen washer arms clogged so bad that there is not enough water pressure coming from them to make them turn, I assure you, nothing is getting cleaned properly there. Also these deposits on the heating element in the W/D make it more difficult for the element to heat the water, as the deposits become thicker, the heating element has to get hotter to heat the water, the deposits may get so bad that the heating element burns out trying to heat the water to the right temperature.

So do your Washer Disinfector a favor by de-liming it weekly or better yet using an acid neutralizer in one of the post wash rinse cycles and save the Stainless steel polish for the exterior.

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.

The classification of masks and respirators is a complex subject with multiple classifications for a variety of working situations, so I am going to just focus on those that pertain to working in decontamination. Let me begin with the fact that you do not need a respirator for decontamination. Although respirators would offer you great protection from aerosolized particulates, they must be fit tested and worn properly to be effective. Furthermore, the more filtration they provide, the harder they become to breathe through. Respirators are best for use in patient rooms where respiratory isolation is indicated.

I did state that a mask for decontamination should be fluid resistant, and when searching for masks, you will see different resistance qualifications and wonder what they might refer to, so I will give some examples here to help out.

If you see BFE > 99%:
This qualification is based on testing done by the ASTM (ASTM F2101-01) for Bacterial Filtration Efficiency, the material being tested is mechanically subject to 3 micron droplets of liquid aerosol containing Staphylococcus aureus at a flow rate of 28.3 L/min, and a material of this classification is capable of filtering out more that 99% of this aerosol. (Make sure this BFE rating is based on the ASTM F2101-01 testing and not on the older Modified Greene and Vesely Test, where a human subject says the word “Chew” and “Sing” distinctly at 10 second intervals for 1 minute through the material being tested in a closed container. The container is then cultured and a bacterial count is taken but there is no specific organism counted).

If you see PFE > 95%:
This qualification is based on Submicron Particulate Filter efficiency testing done by the ASTM (ASTM F2299).This test uses 0.1micron latex spheres at a flow rate 0.5 to 25cm/s the particles are counted with a light scattering photometer before and after passing through the material being tested, so a PFE>95% would mean that more than 95% of these spheres were filtered by the test material.

NIOSH Particulate Filtration Efficiency testing for respirators, (yes I know I said you don’t need a respirator for decontamination) is much more stringent. For healthcare purposes N series respirators apply (N here = Not resistant to oil, the other two classifications are R- Resistant to oil and P-Oil Proof would include oil in their testing aerosol). The challenge here is ~0.3microns liquid sodium chloride aerosol at flow rate of 85L/minute. A collection of at least 95% of this by the material gives the respirator an N95 rating, at least 99% collection would be an N99 and anything 99.7% and over gives the material an N100 rating.(These N,R and P classifications truly only apply to respirators and not face masks)

If the masks make the claim ASTM F1862 120mmhg Fluid Resistance:
This is the actual fluid resistance of the mask based on ASTM testing. In this challenge, a high velocity stream of synthetic blood is aimed at the material being tested at different pressures (80mmHg, 120mmHg and 160mmHg) to replicate blood exiting a puncture wound at a variety of blood pressures. An 80mmHg rating would be a Low fluid barrier classification, 120mmHg would be a Medium and 160mmHg a High.

Another thing you might see is a Differential Pressure Test (Delta P or ∆P) number:
The lower the number here the more breathable the mask is but, the more breathable the mask is the less protection it offers.

Now if this is not complicated enough ASTM F2100-11 has prescribed new mask standards for fluid resistant face masks as follows:

ASTM Level 1
Low Fluid Resistance     80mmHg
Filtration Efficiency      BFE>95%
PFE>95% @ 0.1micron
Breathability-∆P             <4.0mm H2O/cm2
Flame Spread                   Class 1 (low flammability)

ASTM Level 2
Moderate Fluid Resistance 120mmHg
Filtration Efficiency       BFE>98%
PFE>98% @ 0.1micron
Breathability-∆P              <5.0mm H2O/cm2
Flame Spread                    Class1 (low flammability)

ASTM Level 3
High Fluid Resistance 160mmHg
Filtration Efficiency        BFE>98%
PFE>98% @ 0.1 micron
Breathability-∆P               <5.0mm H2O/cm2
Flame Spread                     Class 1 (low flammability)

Wow that’s a lot of information… So now the choice is yours, but if it were up to me, knowing that surgical masks truly do not provided the optimum protection that a respirator does, I would at least choose one that provided me with the most protection, like an ASTM level 3 Mask, or at least one that had all those qualities.

First, you need to lower the temperature on your wash cycle to the optimum high point of your detergent. Most of the enzymes in an enzymatic detergent will begin to denature over 145°F.

Let’s explore a few scenarios where your washer was set previously to a higher temperature:

1. If your wash cycle was set at a temperature over 160°F, it was probably set up for an alkaline detergent which work best at higher temperatures. 
2. If you were previously using another enzymatic detergent at a high temperature and experiencing poor results, these high wash temperatures would most likely be the cause. 
3. If you were using a two detergent system, your wash cycle would only work properly at the higher temperature if you were following the enzymatic detergent wash by an alkaline one. Following the enzyme wash cycle with a plain neutral pH detergent wash cycle at that high of a temperature, would have just been cooking any leftover soil onto your instruments.

With the aforementioned in mind, if you don’t know how to change the temperature on your washer, please have your service tech come in and show you how! All too often, I encounter facilities where no one knows how to adjust the parameters on their washer. This is a very important piece of “know how.” For example, if you’re testing your washer’s cleaning efficacy according to AAMI recommendations, and it appears you are not using enough chemistry to do the job, how are you going to adjust the dosing if you don’t know how to? Don’t become dependent on your service tech for these minor adjustments—a service call takes time, and it’s down time you can’t afford. Besides, learning how to adjust your machine will ensure you are in control in following recommendations and optimizing your cleaning ability.

Furthermore, if you work at a larger facility with a number of shifts, it’s my belief that at least one person on every shift should know the codes to change the parameters. You wouldn’t own a car without knowing how to put gas in it or an oven that only ran at one temperature, right? And you probably know how to change the parameters on your sterilizer for those “wonderful” extended cycles… so why wouldn’t you know how to do the same with your washers?

I know… I went off on a tangent again… but I hope I answered your question and wish you all a wonderful holiday!

First, I recommend you review our blog answers under the “hard water category.” That being said, it has been my experience that most institutions use tap water in their washer-disinfector, all the way up to the final thermal rinse. If the facility has the ability, they will use either de-ionized or reverse osmosis water in this final thermal rinse. Depending on where you live and the time of year, your tap water can contain a lot of dissolved minerals which can end up depositing on your instruments and in your machine’s wash chamber, eventually damaging both. An acid rinse will neutralize these minerals and keep them from forming deposits.

Now, there are certain instruments that cannot be exposed to an acid rinse (such as plated copper instruments); however, these instruments would not fare well in an alkaline wash either. Always check the manufacturer’s recommendations and instructions for cleaning.

The majority of the instruments you run through your washer are surgical grade stainless steel. These instruments have a layer of passivation that helps protect them from corrosive substances. This layer is not added to them, like a layer of electro-plating. Instead, passivation is formed by dipping the instruments in an acid bath which removes the Nickel and Iron from the top part of the instrument surface. The metal that remains is Chromium, which reacts with the acid to form Chromium Oxide–the passivation layer. This layer is very tough and protects the instrument from corrosion, but this layer is also very thin and can be easily damaged. Once this layer is damaged, corrosive substances can make their way to the steel below. It is, however, possible to reinforce this layer of passivation, and one of the means is to expose these instruments to an acid rinse in the wash cycle.

So to answer your question, the acid rinse will not harm your surgical instruments. In fact, it will strengthen and keep them free from corrosive deposits at the same time. Furthermore, the acid rinse will also keep your washer disinfector chamber free of deposit formations.