Advanced Instrument Processing Solutions

Archive for the ‘General Sterile Processing’ Category

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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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We’ve been told that the washer-disinfectors in our facility are supplied with treated water, but no one seems to know what kind of treated water it is. We are a small free standing surgical center so we have no maintenance department to ask, how can we figure out what kind of treatment system we have?

 Since any water treatment system requires preventive maintenance, either resin recharging in case of softened water, filter tank changes in the case of deionized water, or filter replacement in the case of reverse osmosis water, I highly suggest you first talk to the center’s director and make sure this is being done. If you have a water treatment system that is not being maintained it can do more harm than good, throwing the minerals it was filtering back into the water it was treating. Once you find out the company doing your PM’s, call them up and ask them what kind of water treatment system it is. You might even want to ask them to give you an analysis of your treated and untreated water the next time they come in. Since your detergent dosing ratios are highly dependent on your water quality it is good to know it (no matter what the company who makes your detergent claims, “effective in all water qualities” does not mean you would you use the same amount in hard water that you would use in deionized water).

 Since it may take a while to get in touch with the company doing the service on your water system I am going to give you so clues to look for to help you determine what type of water treatment system you have.


 If you can find them, check to see what type of piping is supplying water to your W/D, if the piping is copper you are probably only using softened water in your W/D. Deionized and Reverse Osmosis water are highly aggressive and will basically eat right through copper piping. If your water is DI or RO it the pipes it runs through will be PVC

 If you can find the water treatment system in your facility try and compare it to the pictures I have supplied here as examples of each treatment modality.

A water softening system usually consists of two components a tank that does the softening and another that contains brine that is used to “regenerate” the resins in the softening tank. Again since softened water is not aggressive the pipes in and out of it will most likely be copper.

A water deionizing system usually consists of more than two filtering tanks one multimedia filter, and a cation and anion filter to remove the positive and negatively charged minerals in the water, these tanks need to be changed on a regular basis and since the resins they contain cannot be recharged on premises. Because pure water is a “universal solvent” the piping exiting a DI system will PVC and not copper, DI water would basically dissolve the copper piping in time, but does not dissolve PVC.

A Reverse Osmosis (also known as high purity water) system usually consists of a pre filter and then multiple filters filled with a coiled membrane that only pure water under “osmotic” pressure can pass through. Minerals and other substances dissolved in the water cannot pass through the pores in these filters they are washed “downstream” with the waste water. Because a smaller amount of “high purity water” is produced to the amount that becomes waste, RO systems normally have a holding tank to contain the “pure water”. As with Deionized water, Reverse Osmosis water is highly aggressive and the piping it passes through is PVC.

We have had our wash water tested and the silica level is low, yet we still have a snake skin pattern on our instruments after sterilization. Is the wash water the only source of silicates or can they be coming from somewhere else?

There are other sources of silicate deposits which I neglected to mention in my last post on them

One source is the steam in your autoclave. If water to the boiler is improperly treated, minerals that are dissolved in the water can be carried in the steam and deposit on instruments and the chamber of your autoclave.  Silica is also added to some steam boiler systems to protect the boiler and piping from corrosion, if used in excessive amounts this treatment can be deposited on instruments by the steam containing it.

Another source of silicates is in the detergents you may be using. Sodium Silicate (meta-silicate) is sometimes used in cleaning chemistry as a complexing/chelating, buffering and emulsifying agent. As a complexing agent Sodium Silicate has a great affinity for metals and will bind with dissolved metals in water, thus acting as a water softener and preventing dissolved minerals from depositing on surfaces, it is also a great wetting agent and helps keep the components of detergents in emulsion. Many laundry detergents use Sodium Silicate in their formula for this reason and because it has an affinity for metals, tends not to bind to the fibers of clothing.

Another name for dissolved sodium silicate is Water Glass or Liquid Glass and this brings us to its other use. Sodium silicate can be added to the coolant system of a car to repair gaps in the head gaskets. When sodium silicate in solution reaches a temperature of 100°-105°C (212°-221°F) it adheres to the gaps in the head gasket in the form of glass, thus sealing these gaps. The glass that is formed here can only be re-melted at 810°C (1490°F). In the U.S. governments Car Allowance Rebate System “Cash for Clunkers” program, engines of cars traded in had to be disabled so they could not be reused or resold for parts. This was done by draining the oil from the car, replacing it with 2 liters of sodium silicate solution and then running the engine. When the engine got hot enough the sodium silicate would turn glass like and abraded the engine internals causing it to seize.

Given its affinity for metal and the fact that it turns to glass at the boiling point of water, you would wonder why it would be used in any cleaning chemistry for sterile processing, yet it is, because it is a relatively inexpensive substance. It is more common to find this in cart washer chemistry than those for instruments, but here the sodium silicate takes its toll on the washer more than the carts. After repeated uses the cart washer chamber begins to exhibit a coating that one would assume is calcium, but unlike calcium deposits it is not easily remove, even wire brushes have little effect on it. Also this coating begins to build up freezing the washer arm mechanism and plugging the spray nozzles. With continued use the cart washer will become inoperable.

Sodium Silicate deposits

Sodium Silicate Deposits

Should we be using huck towels for instrument tray liners and wicking in our basin sets or would we be better off using disposable tray lines for this?

I personally would suggest you go with disposable tray liners.  For as long as I can remember most of the institutions I have worked in used green huck towels as tray liners, as corner protection under heavy trays and wicking in basin sets etc.., we did it because it is what we had always done. Now new questions on this practice are arising with good reason. If your institution does not have its own laundry facility you send your laundry out to have it washed, do you know what the laundry facility uses to launder these towels? Is there any residual detergents left in these towels after they are laundered? Residual chemistry in huck towels can deposit on instruments during steam sterilization, many laundry facilities use a high alkaline detergent followed by an acid rinse, residue of the chemistries depositing on instruments can cause corrosion. The washing chemistry is not the only factor here, dye transfer from towels onto instruments also comes into play. I know many of us have seen plastic sterilization cases stained from the dyes in towels, if this dye is transferring onto the plastics cases and staining them, is it transferring onto the instruments too? (my guess here would be yes) Now you have these residual chemistries (detergent and dye) on your instruments and I’ve already stated they can cause corrosion of instruments, but they can also cause allergic reactions in those people sensitive to them, something you don’t want occurring at the surgical site.

Lastly there is the problem of lint. We have all been told that these towels are “lint free” but I assure you if you run a lint brush over them it is not coming off clean. What happens when lint, even the tiniest piece gets into the surgical site, the body reacts to it.  Lint is a foreign body it doesn’t belong where it is so reactions such as granulomas and adhesion formation can occur. Also since a particle of lint is much larger than most bacteria, the body will react to it before it detects the bacterial cells allowing them time to replicate and cause major problems.

Sterile huck towels were originally just used to dry hands post scrub before gloving, we in healthcare are the ones who have repurposed them for a hundred other uses than they were originally designed without a second thought.

We have begun to notice what looks like little tiny holes with rings of rust colored metal around them. What would cause this to happen?

What you are seeing on your instruments is pitting corrosion. Pitting corrosion begins when the passivation layer of a stainless steel instrument is compromised, usually by a scratch. This sets up a situation where you have two different metals exposed, the chromium oxide passivation layer and the iron based steel. When these metals are exposed to an electrolyte, like sodium chloride solution or blood, the more active metal, in this case the stainless steel, begins to corrode at an accelerated rate, while the more noble metal (less active) corrodes at a much slower rate, through an electrical exchange between the two metals (also known as galvanic corrosion) To make things even more complicated the dissolved oxygen in this solution comes into play oxidizing the steel (rust). This chloride based corrosion increases with longer exposure to sodium chloride solution or blood, when exposed to halides (like povidone-iodine) and when instruments are not dried completely at the end of your W/D wash cycle. Even the chlorine in your tap water can increase the corrosion. If you use softened water in your W/D, “salt slippage” from it can hasten the corrosion process too. The rust ring you see around that tiny pin hole will give you an idea of the extent of the damage to your instrument, so that tiny hole can be hiding a large cave underneath it, and that cave is capable of harboring bio-burden, so it might be time to take that instrument and “kiss it goodbye” (if you have an instrument repair contract, check with them to see if your instruments are repairable)

There are a few ways to prevent this corrosion from happening. One is to clean instruments at point of use, by wiping them down with sterile water. I know you are thinking  “yeah you tell the folks in the OR to do that”. I suggest you and your manager meet with the OR director  tell them the problem you are experiencing (take pictures of the instruments) and quote them AORN PNDS:170;198 (Perioperative Nurse Data Set)  “Keep instruments free of gross soil during surgical procedures” and from the same document “Cleaning and decontamination should begin as soon as possible after use. Preparation for decontamination should begin at point of use”. Explain the cause of this corrosion, how detrimental it is to instruments and how much it will cost to replace them.

On the SPD/CSSD side of this equation you must be just as diligent, as soon as instruments arrive in decontamination start cleaning them. The longer the sit, the more they will pit.Have your water quality assessed, I cannot stress this point enough. Water is the true cleaning agent in decontamination, detergents just facilitate the job. Water with too many contaminates leads to a bad cleaning process, excessive use of detergents and deposits on instruments. It is  unfortunate that many institutions in the U.S. would rather spend  money on detergents etc. instead of spending the money to make their water more aggressive (e.g. DI, RO water). If you use softened water in your W/D have the water checked to see whether or not you have “salt slippage”. Lastly make sure when your instruments come out of the W/D they are dry, if they are not have the dry cycle adjusted so they do exit the W/D dry.

I’ve included here a picture of pitting corrosion and a diagram of the process of chloride pitting so you can see how that tiny hole can be hiding a cave.



Our facility currently uses Class 5 Integrating Indicators in all our packs and steam sterilization cycles. Someone recently suggested we use Class 6 Emulating Indicators in our steam sterilizer because they are more accurate. Which do you believe to be the better one for us?

I suggest you stay with the Class 5 Integrating Indicators for now. Class 6 Emulating Indicators are cycle specific, so if the indicator says prevac, 270°F/132°C 4minutes, that Class 6 indicator can only be used in that cycle, not in any other. If you run a gravity load at 250°F/121°C for 30 minutes you will need a separate Class 6 indicator specific for that load. Although a Class 6 can be used as an internal indicator in packs, trays, and rigid containers, as can a Class 3, 4 or 5 CIs  (Chemical Indicators) only a PCD (process challenge device) with a Class 5 integrating indicator and a BI (Biological Indicator) can be used to monitor implant loads and verify the lethality of your sterilization cycle when you do your weekly
(preferably daily!) testing. Yes you could use a Class 6 in the set with the implants, if you have one specific to that trays sterilization parameters, but in the case of an early release of implantable items for an emergency, before the BI results are available, only the results of a Class 5 CI can be used, because they mimic the biological response of the spore contained in the BI when exposed to the optimal saturated steam conditions.

Current Class 6 CI’s are formulated with a complex indicator ink that produce a color change when two or more of the chemical reactions the ink was formulated for are met.  Each ink is formulated to respond to a specific cycle, so in that case you could say they are more accurate, because they will only change color when the cycle they are formulated for has met its sterilization parameters (time, temperature and saturated steam)

Class 5 CIs are formulated to react to 3 stated value temperatures 250°F/121°C, 275°F/135°C and one temperature in between (plus time and saturated steam) to mimic the death curve of a BI. Also the value of 250°F/121°C must be met for longer than 16.5 minutes to mimic this curve.

Again, because you will need a different Class 6 CI for each specific cycle you run in your facility, you will have to increase the amount of inventory you purchase. That and the fact that only Class 5 CIs are recognized for use with a BI PCD at the present time, I would have to suggest you stick with the Class 5 Integrating Indicators.

Our Surgical Center has been having a problem getting loaner instrument trays in a timely fashion. Sometimes we have to “cut corners” to get the trays processed for the surgical cases that needs them. What actions can we take to insure we get the trays in with enough time to process them properly?

Loaner instruments have been the bane of the Sterile Processing Department for what seems like an eternity. Every Sterile
Processing Technician , including myself, has a hundred or so horror stories of having to deal with them . I am going to skip my usual long crazy tirade here (yes I could really go nuts with this) and just start with my suggestions.

First, NEVER CUT CORNERS….NEVER!  Ethically you are obligated to “do the right thing” by complying with the manufacturers IFU for cleaning and sterilization. If loaner instruments arrive at 10:00am and are needed for an 11:30am case, you “cutting corners” to get them done only placates the surgeon and the sales rep. who brought them in at the time they did, the patient, who is your main concern does not benefit from this at all.  Ask yourself, would I want these instruments that have been improperly processed used on a member of my family or myself?  I’m sure the answer will be NO. I understand that this means you will have to “take a stand” and explain your actions to the everyone who is expecting these instruments to be ready (yes, I know they will be screaming about it too), so calmly explain that it is your ethical obligation to “do the right thing” (see above) and ask them if they would want improperly processed trays used on them or their loved ones.

Now if this seems to be a reoccurring problem, which it probably is, I suggest before the problem arises again, get together with the staff from the OR, get your Infection Control person involved, talk to the director of your ASC, even get other surgeons involved (they will listen if you explain the legal ramifications of a Surgical Site Infection from improperly processed instrumentation) and work on getting a policy together and in your facilities policy and procedure manual  to control this problem. Here I would suggest you use the IAHCSMM “Sample Policy and Procedure for Loaner Instrumentation”

as your template. This sample policy is wonderful and covers all the bases, from the responsibility of the OR staff, to the weight of instrument sets, to the responsibility of the sales reps pre and post surgery and of course the responsibility of the SPD/CSSD staff.   Once the policy is complete and documented in your facilities manual, make sure that all the sales reps. who bring you loaner instruments get a copy of it so they know of it and then hold them to it. Without a policy in writing and in your facilities policy and procedure manual, your plight will be a losing battle, so get one started ASAP.


What was modified in the original Greene & Vesley Test method for BFE testing? Why is modified used?

Your question “What was modified in the original Greene & Veseley   test method for BFE? Why is the modified used?” has left me a little perplexed.

When I was answering the query that I received on fluid resistant masks I based my answer on the newest ASTM (ASTM F2100 – 11 Standard Specification for Performance of Materials Used in Medical Face Masks) which was published in 2011. Although I mentioned the modified Green and Veseley test, I  would have to say that since it was originally received for publication in 1961(making it a two years younger than myself) its methodology is a little antiquated compared to the newer ASTM testing. Also since it uses a human subject and counts all CFU’s that are expelled through a mask and deposited on an agar plates in an Anderson impactor, while said human is enunciating prescribed words , the Greene and Veseley test is far less controlled than the ASTM Testing , which uses a test microbe (Staph. Aurues) aerosoled to a prescribed size and pressure and counts the CFU’s that pass through the material being tested (this method also uses
the Anderson impactor for colletion of CFU’s).

As far as the difference between the original and modified Greene and Veseley tests, I am going to take an educated guess here (I have never claimed to be a scientist of any sort, I am first and foremost a Certified Sterile Processing Technician, with too many years for my own good of experience in the trenches) and that is that the modified test employs the use of a sampling chamber and Andersen impactor. To quote the original article  from the  Jounal of Bacteriology   …..
Sampling Chamber.  The sampling chamber was a plywood box (5′ x 16” x 16”) mounted vertically on an angle iron frame. A high efficiency (>99%) fiberglass filter formed the top surface of the box. A fixed metal port projected from the tapered bottom of the box and served as a connection to the air sampler. A sliding “guillotine-like” panel with a flexible plastic collar was provided to permit entry of the subject’s head and neck, at a point 4’ from the sampling port. A glass window was constructed on one side of the chamber for psychological comfort. The only air supply during a test was filtered through the fiberglass and the only source of contamination was the subject. When proper capping was observed and suitable entry precautions taken, a silent subject contributed less than one contaminant/ft³”



Again maybe I’m wrong,  maybe there was another modification I seem to have missed. What I do know is that it is an old test with many controls missing. The newer ASTM testing methods with its controlled microbe, aerosol size, pressure differentials and challenge concentration seems much more reliable than someone saying sing and chew with a mask on in a wood box.

We need more storage, is a sink required or discouraged in sterile processing storage?

The plight of storage in Sterile Processing is a problem in almost every facility,we start out with just enough room for the trays, instruments and supplies we are working with, the next thing we know we are doing cases with instruments we never had done before and have no place to store them properly. Larger facilities like hospitals can eventually work around this, but ASC’s are always challenged here since space is at a minimum. To tell you the truth it is my belief that the architects who design ASC’s need to start consulting with Sterile Processing personnel before they even put pen on paper to draft the SPD/CSSD area.

A sink in sterile storage would only be to accommodate hand hygiene in that area, and would need to be far enough away from any instrument trays or containers to avoid their sterility being compromised by splashing water. Since your facility is an ASC, I would suggest that you forego the sink, unless there are none in the immediate area and focus more on the storage of instruments themselves. Since stacking wrapped instruments on top of each other is frowned upon by most accreditation organizations and most of their inspectors are now dedicating large amounts of time in SPD, you want to have enough storage space to accommodate your wrapped trays. A sink and the space needed to avoid compromised trays would only take up the room you need for storage. If your facility were a hospital with ample room, I would suggest you had a hand washing sink.

I am sure I do not need to tell you this, but since we are talking about sterile storage make sure you have,

Ample air exchanges in the area (positive pressure a minimum of 4 air exchanges per hour),

Proper temperature and humidity (68°F [20°C] to 75°F [24°C] relative humidity between    35% and 70%) with a way to monitor and
record this.

All stored items should be at least 18 inches from sprinkler heads (ceiling) and at least 8 to 10 inches from the floor. If there is an outside wall in your storage area any storage shelves on that wall must be at least 2 inches away from it.

Also make sure your storage area is cleaned on a regular basis and that you keep a record of that too.

Update…. Are there any approved values for residual protein on instruments after cleaning?

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.