Cleaning of Equipment and Materials to be Sterilized

• Introduction
• Why cleaning of goods to be sterilized?
  • The soils on used surgical instruments
  • Importance of quick cleaning after use
  • Cleaning procedure in the CSSD
    1. Initial cleaning/flushing
    2. Sorting for manual cleaning and machine cleaning
    3. Cleaning/disinfection
    4. Verification of the cleaning and drying
• The cleaning action
• Principles of the chemistry of cleaning
  • Water and cleaning
    • Water structure and water properties
  • Problems related to cleaning with water
    • Water prevents wetting of surfaces: surface tension
    • Water cannot dissolve fats and oils
    • Improving cleaning capability of water: Surfactants (tensides)
  • Composition of water: water quality
    • Hard and soft water
    • Chlorides; Acidity of water: pH; Silicates
  • Improving water quality
• Chemicals used in the cleaning process
• Detergents/cleaning agents
• Neutralizers; Lubricants; Rinse aids
• Importance of intermediate rinsing after cleaning
• Disinfection and drying
• Cleaning methods in the Central Sterilization Department
  • Manual Cleaning
  • Pre-flushers
  • Ultrasonic cleaning: the microscopic "brush"
    • Principle of ultrasonic cleaning
    • Application
    • Ultrasonic cleaning equipment
    • Guidelines for ultrasonic cleaning
    • Testing performance of ultrasonic cleaners
  • Cleaning with automatic washer/disinfectors
    • Typical cleaning/disinfection process in an automatic washer disinfector
    • Batch type washer/disinfectors
    • Tunnel washer/disinfectors
  • Personal protection when cleaning
    • Gloves; Plastic Apron
    • Mouth mask, visor and goggles; Splash screen
• Quality control for cleaning
  • Visual inspection
  • Fluorescent powder and fluids with Ultra Violet light
  • Test Object Surgical Instruments
  • Test object for hollow instruments
  • Test object for flexible endoscopes
  • Protein tests
  • Data loggers
  • Validation of washer/disinfectors
• General guidelines for cleaning practice
• Normative references (European)
• Recommended literature related to cleaning
• Websites related to cleaning
• Sources of photos/illustrations

Instruments and materials used during an operation will be covered with blood and remains of tissues; they may have been in touch with chemicals and fluids, dirt and dust. The tubing of hollow instruments may also will be full of these soils. In one way or the other, the items have to be reprocessed so that they can be safely used on another patient again. Cleaning plays an immensely important role in this process... A major requirement for equipment intended to be in touch with inner fluids of the body (the high risk areas) is that they should be sterile. However sterility (the absence of any viable organism) alone is not sufficient for safe use. An instrument, which is covered with sterile dirt or with remains of chemicals or corrosion, still is a serious health hazard. Thus all potentially dangerous soil or remains have to be removed. The health hazard caused by remaining soil (even when sterile) is only one of several reasons why goods to be sterilized, first have to be thoroughly cleaned before sterilization.

1. Removal of all visible dirt, tissue, blood and foreign particles
Medical instruments, especially if they are going to be used in the high-risk areas of a patient, should have no viable micro organisms on them. However also any dirt and foreign particles (even sterile) left on instruments and materials can cause very dangerous complications if they happen to enter a patient through a wound. The body tends to reject any foreign matter that enters the body. A result may be the delay of recovery and of healing with a lot of extra suffering for the patient. It may be even extremely dangerous if during an operation such a dirt-particle would enter the blood stream.

2. Reduction of the bioburden
By cleaning, the population of micro-organisms residing on the materials (known as the bioburden) is reduced considerably. In this way the initial contamination for a subsequent disinfection or sterilization is considerably lower and thus these processes will be more effective, as much less organisms have to be killed. Moreover, because all the visible dirt, including any left-overs of food, blood or pus, were removed, also the breeding ground has been taken away, preventing that any microorganisms that survived, have a chance to multiply. But there is another threat: The left-overs from dead microorganisms can cause feverish reactions if they enter the blood stream. The bits of the left-over dead bodies are referred to as pyrogens. There are microorganisms which contain poisonous chemicals which will be released when they are killed. Also these endotoxins may cause serious diseases. These are additional reasons to reduce the bioburden as much as possible before the killing action (disinfection or sterilization) is done.

3. Protection of instruments against corrosion
Medical instruments are usually expensive precision instruments. Pivots and hinges are very sensitive to any left-over deposits of dirt. Small deposits of blood may easily develop into serious corrosion (rust). This corrosion is aggravated by the moisture and high temperatures during the processes used for sterilization, especially when steam is used. Corrosion may result in serious damage to the instruments and even render them useless or dangerous for the patient. Poor quality of water or incorrect dosing or cleaning agent may be a cause of corrosion. In an adequate cleaning process the chemistry of the cleaning agent, the quality of the water, the materials to be cleaned and the other process variables (temperature and time) are carefully considered, leading to the correct choice of chemicals and processes.

4. Ensure more safe movement of equipment and materials
After cleaning the instruments have to be inspected, sets are to be assembled and packed for sterilization. This requires intense handling. The cleaning and usually subsequent disinfection ensure that these activities can be performed more safely.

Summarizing the importance of cleaning of medical supplies:

• removal of all visible dust and dirt
• removal of breeding ground for surviving microorganisms
• reducing of the bioburden
• protection against corrosion
• ensure more safe free movement of equipment and materials

1. Initial cleaning/flushing
Used instruments are covered with soils and dirt and will be contaminated. The instruments, in their tray, can be put in a deep basin and flushed with a hand shower at temperatures below 50°C. Ensure using a sufficiently deep basin to reduce splashes of water reaching the person performing the washing. Also initial cleaning can be done in a flusher and/or ultrasonic bath.

2. Sorting for manual cleaning and machine cleaning
If not removed yet at the operating theatre, all disposable materials are to be taken out and instruments that cannot be washed by machine shall be separated from equipment that can be machine washed. This work requires great care, as here the chances of injuries is highest. Wearing an apron, gown and protective gloves is essential. Also wearing of a mask is recommended. See section: Personal Protection.

In order to prevent damage to instruments, it is recommended to take the instruments from their tray, into a second tray, and not "pouring" the instruments on the workbench, as this may damage the delicate instruments. In order to ensure that water sprays of the washer reach all surfaces of the instruments, it may be necessary to put large instrument sets in more then one tray.

3. Cleaning/disinfection
By main cleaning all remaining soils are removed. Cleaning can be manual or by machine. In automatic washer disinfectors, first the load is washed, followed by a thermal disinfection by hot water. Usually manually pre-cleaned items, which allow machine washing, are still passing a machine washing cycle, rendering them disinfected.

4. Verification of the cleaning and drying
After cleaning, all instruments are to be inspected for dryness and correct cleanliness. Special attention should be on the "difficult parts of the instruments such as the pivot, serrations, lumens etc. This check is usually done when also performing the functional check of the instruments. For more information see section: Performance testing and validation of cleaning process.

Water: the solvent: water is the carrier in which the soil is going to be dissolved or suspended and transported, away from the items to be washed. It provides the environment in which all cleaning actions take place

A mechanical action: such as wiping, brushing, spraying water under pressure, or ultrasonic waves in water.

A chemical action: detergent with water is used to soak and suspend the dirt and germs. Chemicals in the soil that cause deposits (e.g. limestone) may be dissolved. Cleaning agents may contain additional chemicals, which kill micro-organisms, dissolve proteins and protect instruments.

Heat improves the diluting power of the water and soap or detergent

A minimum time is needed for objects to be subjected to the actions in order to be effective. The time required for adequate cleaning will depend on the methods and intensity of the other actions.

Water structure and water properties
The chemical formula for water is H2O. The formula indicates that a molecule (the smallest particle of a substance) of water it is built up of 2 atoms of Hydrogen (H) and a single atom of Oxygen (O). Through the interactions of electrons circling around the nuclei of Hydrogen and Oxygen the molecule is kept together. The electrons are negatively charged. The nuclei are positively charged. In a water molecule, the outer negative electrons tend to spend more time around the Oxygen nucleus then around the Hydrogen nucleus. This causes the molecule as a whole to be charged negatively at the Oxygen side and positively charged at the Hydrogen side: the water molecule is said to be polar. This polarity causes neighbouring water molecules to be attracted to each other. This so called Hydrogen bond is the cause of a number of fascinating properties of water, that it makes it so special.

• It is a good solvent for a large number of substances
• It has a relative high boiling point
• It is stable
• It has a very high surface tension

These properties also affect the behaviour of water in the cleaning process.

Water prevents wetting of surfaces: surface tension
For cleaning it is essential that water can dissolve and bring in suspension all kind of soils. In order to do that, it is important that water gets in touch with the soils that it should dissolve. In practice, normal pure water does not like to wet surfaces, it tends to bead-up! Inside the water, each molecule is surrounded and attracted by other water molecules due to the dipole nature of the water molecules. However, at the surface, those molecules are surrounded by other water molecules only on the water side. A tension is created as the water molecules at the surface are pulled into the body of the water. This tension causes water to bead-up on surfaces (glass, fabric). The drop will hold its shape and will not spread: the beading-up of water prevents the wetting of the surface and thus inhibits the cleaning process.

Water cannot dissolve fats and oils
By its polar nature water can dissolve a great number of substances: Generally it can be said that substances with a polar structure like water itself, can be dissolved in water. These are substances such as many salts, acids, bases etc. They are known to be hydrophilic (water-loving). However an important group of soils is not polar by nature and thus cannot be dissolved in water. These substances are said to be hydrophobic (afraid of water). Among them are fats, oils and proteins. These however are all substances, which are found abundantly on used surgical instruments! Thus water alone cannot do our cleaning job properly. For adequate cleaning it is essential that also these soils can be removed.

Improving cleaning capability of water: Surfactants (tensides)
A first requirement is to make sure that the water will want to get in touch with the surface it touches. This means that the surface tension should be reduced. By adding a chemical that reduces the surface tension, the water can spread and wet surfaces. Chemicals that are able to do this effectively are called surface-active agents, or surfactants. Also the term tensides is used. Surfactants are substances with molecules that on one end tend to be attracted to water (the hydrophilic end) and on the other end tend to attach to fatty substances (which is repelled by water: the hydrophobic end). These substances are said to make water "wetter." Surfactants also are able to dissolve the fats and oils: they loosen them and emulsify (disperse) them into the water. Also they ensure that they keep the soils in suspension so that they can be flushed away with the water. Common surfactants are soaps and detergents.

Also other substances such as phosphates can emulsify fats and oils, and are used in detergents. They however do not cause considerable reduction of the surface tension.

By nature, water contains a wide range of substances. It may contain dust and dirt particles, micro-organisms and minerals. Minerals are chemicals found in nature, such as cooking salt (NaCl), Gypsum (CaSO4), Calcium bicarbonate (CaHCO3) and many others. When diluted in water, these minerals usually are split up ions, which are charged particles. The split-up results in positively charged ions: the cations (attracted by a cathode, the name of a negative electrode), mainly Hydrogen and metal ions (K, Na, Ca, Fe, etc.) and negatively charged ions, the anions (attracted by the anode: a positive electrode). Anions are usually left-overs of acids and salts). The concentration of these ions in water very much depends on the geological structure of the site where the water is coming from. In areas with lots of calcium (lime) and magnesium, the water will contain ions of these metals.

Hard and soft water
When water contains high amounts of certain salts of calcium and magnesium (the bicarbonates) it is known as "hard" water. At higher temperatures these salts are not soluble in water and tend to form a hard scale on surfaces covered with such water. This causes discoloration of instruments and can cause damage to the cleaning equipment. That is why these minerals have be removed or modified to salts which remain in solution and flushed away with the water. This can be done by additives in the cleaning agent. Another method, which is even better, is by removing these minerals from the water before it is used for cleaning. This is known as water softening: a process where the insolvable calcium and manganese salts are replaced by a solvable sodium salt. The sodium salt remains in the water solution; it thus does not cause deposits.

Chlorides
Piped water may contain chlorides, or chlorides are coming into the water with the soils during the cleaning phase. Bodily fluids usually contain physiological salt, which naturally contains chlorine. Chloride ions are very reactive and easily pull the iron molecules of the steel into the water solution. Thus chlorine that is dissolved in water can cause serious corrosion of any metal instruments and is clearly visible by holes in the steel, known as "Chloride induced pitting". It is essential that any chloride will be removed during the last phase of the cleaning process.

The longer-term effect of chloride on corrosion can easily be demonstrated by submersing an instrument in salty water. Within a few hours, even the best, high quality stainless steel instrument will already start corroding. After a day a brownish cloud of rust will have formed. This is known as "bleeding" of the instrument.

Acidity of water: pH
In pure water the vast majority of water molecules stay together. However in a rare case, due to the hydrogen bond, the nucleus of a Hydrogen atom (a proton) of one molecule jumps to that of a neighbouring molecule. This will then have 3 hydrogen atoms attached to it and will become a positively charged H₃O⁺ ion. The other water molecule, which has lost the hydrogen nucleus, but kept its electron, becomes a negatively charged OH^- ion. In pure water this happens about 1 in 10.000.000 (10⁷) molecules. In pure water both the amount of H₃O⁺ and OH^- are equal and its acidity, also indicated as pH, is 7 (the number of zero's of the concentration) and is said to be neutral. It is found out that when the concentration of H₃O⁺ becomes higher then the OH^- the solution becomes acid (for example 1 in 10.000 molecules or 10⁴). The pH will be less then 7. In the example the pH is 4. If the number of H⁺ becomes lower then the number of OH^- the solution becomes basic. This acidity of water has great influence on the cleaning properties of the chemicals used for cleaning and affects the corrosion caused by chemicals and the water.

Silicates
In locations where the tap water is taken from sandy locations, water contains silicates: they are minerals with silicon in it (the main component of sand). Silicates are salts that tend to deposit on instruments causing opaque (at the beginning), or dark blue layers (when growing thicker). By adequate water treatment (de-ionized water) where the vast majority of minerals including the silicates are removed, this problem can be solved. Also cleaning agents may have chemicals, which help to keep silicates in solution and thus prevent silicon salt deposits.

Filtering: In order to remove major particles of dust and dirt floating in water, it is passed through a sieve or filter element or filter bed that catches small particles. The tighter the mesh of the sieve, the smaller the particles must be to pass through. Filtering is not sufficient to completely purify water, but it is often a necessary first step, since such particles can interfere with the more thorough purification methods or would clog-up these systems very quickly making them extremely expensive to be operated. Therefore usually a prefilter system is installed.

Distilling: Distillation involves boiling the water to produce water vapour. The water vapour then rises to a cooled surface where it can condense back into a liquid and be collected. Because the solutes are not normally vaporized, they remain in the boiling solution. However distillation does not completely purify water, because of contaminants with similar boiling points and droplets of un vaporized liquid can be carried with the steam. Still, 99.9% pure water can be obtained by distillation. Distilling results in high-quality water; however an enormous amount of energy is required for this process. In situations where large quantities of high-quality water is needed (as for the washing process and steam sterilization in the CSSD), other methods, such as water softening, de-ionizing and reverse osmosis are used.

Water softening by ion-exchanging

The salts causing the water hardness, such as Calcium bicarbonate (CaHCO₃) and Magnesium Chloride (MgCl₂) and tend to deposit, are exchanged with salts of Sodium. These Sodium salts are dissolved very well in water, and thus are not deposited. In a water softener, the hardness ions are exchanged with the Sodium ions. This can be done by passing the water through a charged resin column that has side chains that trap calcium, magnesium, and other heavy metal ions and replaces them by Sodium ions. The sodium salts are soluble in water and thus will not cause any deposits. In stead of resins also zeolites are used.

When saturated with hardness ions, the resin can be regenerated with sodium ions by flushing with salty water (brine) and the resin can be used again for water softening.

De-ionization by two-step ion-exchanging

In this process, all ions in the water solution are removed in a two-step process. In the first stage the metal ions (the positively charged cations) are exchanged by H⁺ ions. In a second stage also the remains of the acids and salts, (the negatively charged anions), are exchanged by OH^- Ions. The H⁺ and OH⁺ together form H₂O: water. In this way all minerals are removed.

In many laboratories, this method of purification has replaced distillation, as it provides more quickly a high volume of very pure water. Also water for the final rinse in the cleaning process usually is treated this way. Water purified in this way is called de-ionized water, demineralized water or demi water.

Due to their very weak bonding with the resins, silicates, causing an opaque or bluish layer on stainless steel instruments, may pass through ion-exchangers, especially after the resins are getting close to saturated. Due to the fact that silicates do not increase the conductivity of the water, the presence of silicates may be overlooked easily.

Reverse osmosis: also known as hyperfiltration. Mechanical pressure is applied to the impure solution which is forced through a semi-permeable membrane. When the pore size of the membrane is approx 0.0005 micron (compare to bacteria, which are 0,2-1 micron). The term is reverse osmosis, because normal osmosis would result in pure water moving in the other direction to dilute the impurities. Reverse osmosis is theoretically the most thorough method of large-scale water purification available. As the membrane is very sensitive to damage by Chlorine, metal ions and other impurities, usually water filters and water softening systems are used in combination with the Reverse Osmosis unit.

These products are the main chemicals used in the cleaning process. They may contain surfactants, alkali, enzymes, corrosion inhibitors, solvents etc. For the cleaning of surgical instruments, dedicated cleaning agents have been developed with the typical soils found on used instruments in mind. Products are available for manual cleaning and automatic washer disinfectors. Also for delicate instruments such as flexible endoscopes dedicated products are available.

An enzyme is, in biology, a special protein molecule whose function is to facilitate or otherwise accelerate most chemical reactions in cells. They are biological catalysts. That can break down large molecules such as proteins, fats and starch to smaller pieces, which then can be diluted in water. In this way stains caused by blood and fats can be removed. For breaking down each group of biological substances there are different, specific enzymes. For example proteases break down proteins; Lipases break down fats (lipids). In the process of breaking down these large molecules, the enzyme itself is not used up. When given sufficient time very small quantities can break down large amounts of proteins. As the soils of used surgical instruments contain much of the organic soils, cleaning agents for this purpose, may also contain enzymes.

Lubricants

Surgical instruments are prone to corrosion, especially at the steel surfaces in the hinges. By nature, stainless steel has a protective layer, of Chromium oxide, which becomes thicker with time. Due to friction, the protective surface of the steel is damaged. At these places the bare iron will be exposed and the steel will easily be corroded. Also mineral left-overs (residues) in the hinges stimulate corrosion. That is why lubricants are added to the rinsing water, which form a protective layer on the steel. Lubricants are usually paraffin oils.

Rinse aids

After disinfection with hot water, the load is to be dried. As seen before, water has a high surface tension, and water tends to bead up on the surface of the materials. These drops only evaporate very slowly and thus results in a long drying time. That is why in the water used for the final rinse a rinse aid can be added. It contains a surfactant, which causes the spreading of the water on the surface. Due to the increased surface, the water will evaporate more quickly and the drying time can be reduced considerably. In this way the energy consumption of the total process is also reduced considerably.

Manual Cleaning

In order to reduce risk, any cleaning that can be done by machine is done so. As manual cleaning is the most risky task within CSSD, whenever possible, cleaning is done by machines. Manual cleaning is done when machine cleaning is not possible.

Brushes: external and internal

A wide range of brushes is available for manual cleaning, suitable for individual cleaning tasks.

External brushes: for cleaning the outside surfaces of objects. They may have hard or soft hairs.

Internal brushes: for cleaning of hollow instruments. A range of diameters and lengths is available for any type/size of hollow instruments and materials.

Do not use steel brushes for cleaning, as they damage the protective layer on stainless steel and aluminium instruments!

Sponge or towel

Delicate instruments such as optics may be cleaned by soft towel or sponge.

Spray gun

A spray gun is essential for rinsing/flushing of hollow instruments. Various nozzles are available for a range of specific cleaning applications.

Hand shower

The hand shower can be used for an initial rinse of instruments.

Use a deep basin, which will help to prevent splashing sideways. Make sure that the water pressure is not too high in order to limit splashing. Only use cold water for blood removal! Protect yourself by wearing gloves and mask, or use a splash screen. See section personal protection

Instrument flusher

In a flusher, instrument sets are submerged and spayed by powerful jets of water. The majority of dirt and soils are flushed away. Instruments of which not all soil is removed, either are cleaned additionally in an ultrasonic cleaner or are manually cleaned. Subsequently usually they are washed/ disinfected in a washer/disinfector.

Basics: Water cavitation

At a given temperature water can exist only in the liquid state above a minimum pressure. When the pressure decreases below the critical pressure, the water will become a gas. For example: When the water is 60°C, at atmospheric pressure (0 Bar on the pressure scale) that water is fluid. If the pressure is reduced to below of -.8 Bar the water cannot exist as fluid anymore and will evaporate. In an ultrasonic cleaner, water is vibrated at ultrasonic frequencies. These ultrasonic waves cause very fast pressure decreases and increases in the fluid. The sudden decrease causes moments that water cannot exist in the fluid state anymore and gas bubbles will form. At the subsequent increase of the pressure the bubbles will collapse again. This process of the creation of minuscule bubbles or cavities in the water, is known as cavitation.

Microscopic brush: Caused by cavitation

Ultrasonic cleaning depends upon this process of cavitation, the rapid formation and violent collapse of minute bubbles or cavities in a cleaning liquid. This agitation by countless small and intense imploding bubbles creates a highly effective scrubbing of both exposed and hidden surfaces of parts immersed in the cleaning solution. As the frequency increases, the number of these cavities also increases but the energy released by each cavity decreases making higher frequencies ideal for small particle removal without damage of the items to be cleaned.

Components of an Ultrasonic cleaner

1. Ultrasonic generator

Through the mains electricity supply the electric waves at ultrasonic frequencies are created. (depending on the application 25kHz-50kHz).

2. Transducers
One or more transducers (vibrating elements) transform the electric waves into ultrasonic sound waves.

3. Cleaning tank
The cleaning tank contains the cleaning fluid (usually water with an enzymatic detergent). At the bottom of the cleaning bath the transducers are attached.

Recently also chemical indicators appeared on the market, which can be used for checking the correct operation of an ultrasonic bath. It actually verifies the cavitation capability of the ultrasonic bath. The cavitation triggers a chemical reaction in the test fluid, causing a clear colour change. The test device is a closed vial/capsule containing the fluid with glass beads in it. The vial is put in the ultrasonic bath, which is switched on at specified frequency, time and temperature. When an effective cavitation is reached, the colour of the fluid in the vial changes from green to yellow. Advantage of this system is that it can be used together with the load to be cleaned.

Batch type washer/disinfectors
These machines are also referred to as batch machines. This means that cleaning takes place in batches: a load is processed completely in a single chamber and then taken out of the machine. As opposed to tunnel or takt washers, in which the various phases of the process take place in a number of subsequent chambers.

Depending on its size a number of standardized instrument trays can be put on a load carrier (also called insert) and rolled into the cleaning chamber. Dedicated load carriers are available for a wide range of instruments and materials, covering such diverse applications as instruments, containers, MIS instruments, anaesthetic material, theatre clogs and baby bottles. Especially for hollow instruments it is essential that they are also cleaned and rinsed inside. Each instrument therefore is individually connected to the water flushing system. Depending on the type of load, a program can be selected. For newer machines inserts may have an indexing system that can be recognized by the machine and causes automatic selection of the appropriate cleaning program thus reducing the chance of human error of selecting the wrong program. The entire program runs fully automatic and takes place in the same cleaning chamber.

Advantages of these machines are

• Compact design
• Less complex then the tunnel washers; thus lower chances for break downs
• Washing capacity can be increased by installing additional units side by side. This extra capacity gives back-up in case of break-down.

In case still larger capacities are needed the installation of tunnel washers can be considered.

Batch washer/disinfectors can be equipped as single door or double door units (Pass-through type). The pass-through type is recommended as it forces separation of the clean and dirty area, thus reducing chances for cross infection. The doors should be interlocked, making sure that only one door can be open at a time. Doors may be manually operated or can be fully automatic powered doors. When high capacity is needed multiple units can be fed by an automatic loading and unloading system.

Tunnel washer/disinfectors

In tunnel washer/disinfectors also referred to as takt machines, the load is put on a conveyer belt, which is passing through a number of compartments with doors closed during action, in each of which a subsequent step of the cleaning process takes place. In this way a tunnel washer may have e.g. 4 compartments: Prerinse, ultrasonic bath, main washing, and disinfection/drying.

As the machine simultaneously processes in all compartments, it can have a considerably higher throughput then the batch machines, and thus are used in locations where high volume cleaning capacity is needed.

A tunnel washer may turn out 30 or more instrument trays per hour. As the tunnel washer is not designed to clean complex instruments, with channels or corrugated airways, they must be manually cleaned or cleaned in a separate machine. Another disadvantage of such machines are their complexity and thus vulnerability for machine failures. Breakdowns will result in considerable reduction of cleaning capacity. Usually in facilities having tunnel washers also have one or more batch machines installed for back-up.

Gloves

Wear gloves while cleaning instruments and equipment. Thick household gloves may work well.

Note: even when wearing heavy-duty utility gloves, care should be taken to prevent needle stick injuries or cuts when washing sharps! In case of an injury, follow the protocol for such injuries as prescribed by your hospital/facility.

When scrubbing ensure that any splashing moves away from you. Also you can do the scrubbing under water.

Plastic Apron

The apron will prevent moisture reaching clothes.

Mouth mask, visor and goggles

A mask will protect against breathing-in of splashes or droplets of aerosols. A visor or goggles give protection for your eyes.

Splash screen

A splash screen above a cleaning basin can be used to prevent splashes entering eyes, mouth and nose. It reduces the need for wearing a visor and/or mask thus offering more breathing comfort. The screen should move smoothly and offer clear sight on the materials to be cleaned.

Visual inspection

The most basic verification of the performance of a cleaning process is by carefully inspecting the cleanliness of instruments and materials. All objects should be free of any remaining soils, deposits, pitting etc. Take special care for checking pivots, box joints, instrument serrations. Also cracks can be caused by corrosion, which again is a result of poor cleaning performance.

An inspection lamp with a magnifying glass can be very useful for identifying remaining residues.

Fluorescent powder and fluids with Ultra Violet light

For demonstrating effectiveness of cleaning test kits is available. The kits use a fluorescent powder or fluid, which are applied to the instrument or materials. The materials are then cleaned in the normal way. By using an ultra violet light any particles/soil that were not removed will light up. A great educational tool! It clearly identifies the weak points in the cleaning procedure: usually teeth, joints and screws, all those places where soil can collect but which are easily forgotten. This kit can also be used for training on improving hand-washing procedures. As its quantities usually cannot be calibrated, these materials cannot be used for validation of the cleaning procedures.

Test Object Surgical Instruments

Several attempts are made in order to have a universal test soil for the verification/validation of the performance of washer disinfectors. The TOSI (Test Object Surgical Instruments) is becoming an accepted tool for testing cleaning performance. It is a metal strip, partially covered with a soil, with similar characteristics as human blood. The strip is half encapsulated in a plastic cover, designed such that access of the cleaning agent gets more difficult from one end to the other. They are calibrated such, that when a cleaning system manages to clean the device, it can be assumed that optimal conditions for cleaning of instruments will be achieved.

Test object for hollow instruments

For testing cleaning performance for hollow instruments test devices are available, simulating hollow instruments. A strip similar to the test strip for normal instruments, is put in a capsule, with lumens on both sides. The dimensions of the test object are similar to long hollow instruments. Its operation is the same as the normal test object.

Test object for flexible endoscopes

The test object simulates the lumen of a flexible endoscope. Its operation is similar to test objects for normal instruments and hollow instruments.

Protein Test

These are test for the detection of blood residues on surfaces. So with such a test the cleanliness of the actual load items are tested. The tests are based on an enzymatic reaction. Minute residues will cause a quick colour change. Typical: 0,1 microgram within half a minute. A swab is used to take a sample from a surface, e.g. a surgical instrument. The swab is put in the indicator and check for the colour change (e.g. transparent to blue-green).

Data loggers
For a quantative analysis of a cleaning process it is essential to measure temperature and time throughout the cleaning cycle, in different locations of the load. Solid stated data loggers can be used for this purpose. After the process they can be connected to a computer and the process data loaded into a program for analysis of the process.

Validation of washer/disinfectors
According to new standards, the processes of washer disinfectors need to be validated. Clean products are a result of a well-loaded washer/disinfector in a well operating washer disinfector, running the right process. The cleanliness has to be verified against an accepted standard of cleanliness, in terms of residues and micro-organisms.