IS YOUR WATER WORKING FOR

YOU???

WHY IS WATER SO IMPORTANT WHY IS WATER SO IMPORTANT IN A MEDICAL DEVICE IN A MEDICAL DEVICE

REPROCESSING DEPARTMENT?REPROCESSING DEPARTMENT?

• Used for pre-cleaning instruments at POU

• Used in manual cleaning, rinsing

• Used in ultrasonics, pasteurmatics, washer disinfectors

• Converted to steam for sterilizers

IMPORTANCE TO IMPORTANCE TO INSTRUMENTSINSTRUMENTS

• An instrument inventory is a significant expense to any facility & not easily replaced

• Metal instruments are made of a high grade of stainless steel but can be damaged during reprocessing not only by improper handling, but also by poor water quality

• Instruments need to be properly reprocessed in order to maintain functionality, sharpness, etc...

IMPORTANCE TO IMPORTANCE TO INSTRUMENTSINSTRUMENTS

• Corrosion of instruments can cause instruments to break (stress cracks), scissors to become dull, loss of integrity of instrument surface (holes, rust)

• Cracks or corrosion spots can harbour micro-organisms, debris and therefore interfere with the effectiveness of sterilization

• Stains, water spots, mottled finishes cause end user to believe the instrument is not clean and therefore ‘suspect’ the sterility of the instrument bundle (instruments look dirty)

WHY DO WHY DO STAINLESSSTAINLESS STEEL STEEL INSTRUMENTS INSTRUMENTS CORRODE?????CORRODE?????• Surgical instruments have a ‘passive’ layer of

chromium and iron oxide• This ‘passive’ layer is what protects the

instrument from corrosion• The more chromium in the ‘passive’ layer, the

more resistant the instrument is to corrosion• ‘Passive’ layer can be damaged by: handling,

acidic/alkaline detergents, dried soil/blood, saline, chlorine, hard water deposits, etc.... ¹

POSSIBLE WATER –BASED POSSIBLE WATER –BASED CAUSESCAUSES

• Rust and pitting – usually caused by chlorides in water, rust in pipes to washer/sterilizer, boiler carry-over

• Rainbow colours on instruments – possible cause is excessive silicates in water (by-product of sand) or dissimilar metals in contact during reprocessing

• Spotting (light/dark)– minerals in water; seen when instruments dry and water evaporates leaving water spots

• Black/brown – low pH, exposure to chlorine• Black – possible exposure to ammonia• Powdery residue on aluminum – low pH water (acidic) • Etched aluminum – high pH solution (alkaline)

Silicate staining

Pitting due to chlorides

Rust or stain?

Improperly cleaned; pitted; rust

Low pH or Ammonia

Rust caused by saline

BUT WE USE GREAT CITY BUT WE USE GREAT CITY WATER!WATER!

“Water that is safe to drink may not be acceptable for reprocessing or for sterilizing surgical devices....”²

“Most public water systems include additives such as chlorine, dissolved salts and sometimes significant naturally occurring mineral content, and even organic contaminants, bacteria and endotoxins.”²

“Tap water is contaminated with toxic heavy metals, synthetic organic chemicals, chlorine, biological parasites and thousands of other harmful contaminants. According to a research group, ‘EPA reports show that U.S. water supplies contain over 2300 cancer causing chemicals’. In addition, all the chemicals we use will ultimately show up in our tap water. There is no new water; our planet keeps recycling the same water. Furthermore, water treatment facilities are not designed to remove organic chemicals and toxic heavy metals, like lead.”²

“Stainless instruments are susceptible to pitting when there is an increase in chloride content in the water, when there is an increase in temperature, with decreasing pH values, increased exposure times, insufficient drying and concentration of chloride from dry residues to instrument surfaces after evaporation.”²

PRINCIPLES OF WATER PRINCIPLES OF WATER USEUSE

• Water, by itself, does not clean instruments• Water, with enzymatics and detergents clean

instruments (explain how water works)• Water compatible substances can be fairly

easily dissolved by water, but other substances cannot; these ‘other’ substances include fats, oils and proteins – which we find every day on surgical instruments in the form of blood, fat, body fluids, tissue, etc...

.• The first washer phase is done with warm (not hot) tap water and injections of enzymatic, so blood and proteins are not ‘set’, but rather the break down begins.

• The wash phase with tap water and detergent, causes the debris to be loosened and dispersed into the water. The water volume and presence of detergent holds the debris in ‘suspension’, so it does not re-settle on instrument surfaces.

• The rinse phase is done with hot water. The rinse water should be purified water so all debris, chemicals, minerals, etc rinse away cleanly from instrument surfaces. SO, WHY NOT TAP WATER???

THIS IS WHERE IT GETS A THIS IS WHERE IT GETS A BIT (MORE) TECHNICAL!!!BIT (MORE) TECHNICAL!!!

• Reverse osmosis (RO) water, de-ionized (DI) water or distilled water all remove the impurities that would normally cause damage to and deposits on instruments

• Generally is used only for the rinse cycle due to system capacities, necessity and cost

• Each has their own advantages and disadvantages, but all hold a distinct advantage over tap water for ‘final rinse’ water

DISTILLED WATERDISTILLED WATER• Is the least likely method to produce pure

water for an MDRD• Water is boiled in a distiller. The impurities

are ‘heavy’ and stay in the boiling water while the lighter steam rises and is drawn off. The steam is then allowed to condense back into a nearly pure water form for use.

• Is not practical when large volumes are needed as it requires a large amount of energy to produce, therefore significantly increased costs and considerable infrastructure

R.O. WATERR.O. WATER• Water is passes through pre-filters, then is

forced through pores of a semi-permeable membrane into a collection tank

• Pore size is approx. 0.0005 micron (bacteria are generally 0.2-1 micron & viruses 0.02-0.4 micron)

• Very effective in removing most minerals, metals, micro-organisms

• Membranes vary in quality, pore size; are sensitive to damage by chlorine, metal ions

• Membranes can be self-cleaning to a degree

R.O. WATER ISSUESR.O. WATER ISSUES• Membranes become plugged or contaminated,

requiring changing; pre-filters require changing• Water temperature and pressure need to be

maintained according to manufacturer’s specs to maintain system efficiency

• Water used to wash across the face of the membrane for cleaning, is wasted – flows down the drain

• Water purity begins to decline almost immediately due to buildup of contamination on membrane - needs to be monitored for regular maintenance of filters, membrane changes

D.I. WATER – a little D.I. WATER – a little chemistry firstchemistry first

• “When diluted in water, minerals usually are split up ions, which are charged particles. The split up results in positively charged ions: the cations... mainly hydrogen and metal ions (K, Na, Ca, Fe,etc) and negatively charged ions, the anions. Anions are usually left overs of acids and salts.”³

The above statement is the principle that DI water is founded upon.

D.I. WaterD.I. Water• Water is passed through carbon filters, reverse

osmosis, then through 2 resin tanks. The first tank contains cation resin which removes the positive ions and replaces them with hydrogen ions, while the second tank contains anion resin which removes the negative ions and replaces them with hydroxyls. When the hydrogen and hydroxyl ions combine, they form pure water. 3,4

• Water purity is measured by the ‘resistance value’ in Meg-Ohm cm (won’t conduct electricity)

D.I. WATER ISSUESD.I. WATER ISSUES• A meter is attached to the DI system for daily/weekly

readings, as the water quality can change quickly once the resin tanks become depleted.

• The drop in resistivity from a starting point of 17-18 Meg Ohms does not occur gradually, but rather exponentially. Once the resistivity drops below a certain point, the tanks are no longer replacing the removed ions, so the water becomes ‘hungry’ and attracts ions from other sources (ie: the piping, the washers, the washer racks, instruments, containers, etc)

• DI systems do not remove organic contaminants or micro-organisms because these do not have a positive or negative ion charge

D.I. WATERD.I. WATER• Our experience: >We noticed the instruments appeared dull (we had our

chemistries checked by vendor) >We noticed dark staining in jaws and box locks, then

over entire surfaces (we had chemistries checked again by vendor, and had maintenance do water quality tests)

>Aluminum trays began to dry with a fine powder on them (we had maintenance check DI water system and biomed check RO water system)

>Metal pitting started on older instruments and copious amount of powder on aluminum trays started (brought water for independent water analysis) and discovered what the issue was and how to fix

REFERENCES1 - Spotting, Staining, and Corrosion of Surgical Instruments; H.J. Kaiser PhD/ P.

Schwab MBA/ J.F. Tirey MA; Copyright 2012 Virgo Publishing; Posted in Infection Control Today 10/01/2000

2 - Water Filter Comparisons. Ralph Nadar Research Group; Copyright 2012 Virgo Publishing; Posted on Infection Control Today 04/29/2009

3 - DI Water; DI Water Specifications. TM Associates. Santa Clara CA.4 - DI (Deionized) Water – Part 1: System Overview. Digital Matrix. Copyright 2012.