Cleaning, Disinfection and Sterilization

This is Unit Nine of Medical Assistant Prep. Units Seven and Eight protected people from germs. This unit protects them from the instruments and surfaces between patients, through three levels of removing germs: cleaning, disinfection and sterilization. Carry one idea through this lecture. Each item gets the level of processing its risk demands, and each check answers a different question, so no single check proves an item safe. A constructed afternoon at the end puts every check to work. By the end you will be able to tell the three levels apart. To sort items by their risk category. To sterilize and monitor a load with three kinds of indicator. And to store sterile supplies and keep a sterile field sterile.

Three entries on the levels: what each removes, why cleaning comes first, and how manual cleaning works.

Cleaning, disinfecting, sterilizing.

MAS 201 Three Levels of Clean

Cleaning, disinfection and sterilization are three different levels of removing germs. Cleaning removes soil and organic matter; disinfection kills most microorganisms but not all spores; sterilization destroys all microbial life, spores included. Use the level each item needs. A disinfected instrument is not a sterile one.

Soil shields germs.

MAS 202 Cleaning Always Comes First

Thorough cleaning must come before disinfection or sterilization. Soil and blood left on an instrument shield germs from the disinfectant or the steam; once dried or baked on, it is harder to remove and the process may fail. Rinse or presoak instruments soon after use so that blood does not dry on them.

Brushes and flushing.

MAS 203 Friction and Fluid

Manual cleaning relies on two things: friction and fluid. Friction means scrubbing soiled areas with a brush; fluid under pressure flushes soil from channels a brush cannot reach; ultrasonic cleaners loosen soil with sound waves in water. Open hinged instruments fully, so cleaning reaches every surface.

Five entries on risk: the three categories, what each needs, and reading a disinfectant's label.

Critical, semicritical, noncritical.

MAS 204 Three Categories of Risk

Patient-care items are sorted into three categories by infection risk, and the category decides the processing. Critical items enter sterile tissue or the bloodstream, such as surgical instruments, and must be sterile. Semicritical items touch mucous membranes or broken skin, such as some endoscopes and respiratory equipment, and need at least high-level disinfection. Noncritical items touch only intact skin, such as blood pressure cuffs and crutches, and need cleaning and low-level disinfection. Classify by use, not by name. An item that usually touches intact skin becomes higher risk when used on broken skin or a mucous membrane.

Sterile, always.

MAS 205 Critical Items Must Be Sterile

Any item that enters sterile tissue or the vascular system must be sterile, because any contamination could transmit disease. Most critical items are bought sterile or sterilized with steam; heat-sensitive items use other approved sterilization methods. A critical item that may have been contaminated is not used until it is reprocessed.

High-level disinfection.

MAS 206 Semicritical Items Need High-Level Disinfection

Semicritical items should be free of all microorganisms, though small numbers of bacterial spores are acceptable. High-level disinfection removes all microorganisms except some spores, and it must follow thorough cleaning; intact mucous membranes generally resist infection by common spores. Follow the disinfectant's directions exactly, or the item is not safe.

Cleaned in place.

MAS 207 Noncritical Items Are Cleaned Where They Are Used

Noncritical items touch only intact skin, which is a strong barrier to most germs. Items such as blood pressure cuffs and crutches can be cleaned and disinfected with low-level disinfectants right where they are used, without being sent away for processing. Low risk is not no risk; clean noncritical items between patients.

Contact time.

MAS 208 Read the Disinfectant's Label

Each disinfectant works only when it is used as its label directs. Most registered disinfectants state a contact time on the label, often ten minutes, meaning that the surface must stay wet with the product for that long. Wiping on and immediately wiping off may not disinfect at all.

Six entries on sterilization: steam and its temperatures, table-top units, and the three kinds of indicator.

Four parameters.

MAS 209 Steam Sterilization

Saturated steam under pressure, in an autoclave, is the most widely used and most dependable method of sterilization. It depends on four parameters: steam, pressure, temperature and time. Every item must have direct steam contact at the right temperature for the required time. Steam must reach every surface, so pack and load items to let it circulate.

Gravity and prevacuum.

MAS 210 Two Common Steam Temperatures

Two steam-sterilizing temperatures are common: about two hundred fifty degrees Fahrenheit and about two hundred seventy degrees Fahrenheit. A wrapped load needs about thirty minutes at the lower temperature in a gravity sterilizer, or about four minutes at the higher one in a prevacuum sterilizer. Times also vary by item and wrapping, so follow the manufacturer's directions.

Small units, full monitoring.

MAS 211 Table-Top Sterilizers in the Office

Portable table-top steam sterilizers are used in outpatient, dental and rural clinics for small instruments. Like any sterilizer, a table-top unit must be checked to confirm that it reaches the conditions sterilization requires. A small sterilizer still needs the full monitoring routine described in the next three videos, every time it is used.

Three questions.

MAS 212 Three Kinds of Indicator

Sterilization is monitored with three indicators, each answering a different question. Mechanical indicators, the printout or gauges, record each cycle's time, temperature and pressure. Chemical indicators are inks that change color under sterilizing conditions, placed outside each pack and preferably inside too. Biological indicators are strips or vials of highly resistant spores showing whether living organisms were actually killed. Only the biological indicator measures killing power. The other two can look right when a load was not sterilized, so all three are used, and a failure in any one keeps the load out of use.

Processed, not proved sterile.

MAS 213 What a Chemical Indicator Proves

A color-changed chemical indicator shows that a pack went through a sterilization cycle; it does not prove the contents are sterile. An outside indicator confirms that the pack was processed, and an inside indicator shows that the sterilant reached the contents. If either indicator shows inadequate processing, do not use the item.

Weekly at least.

MAS 214 Biological Indicators at Least Weekly

Steam sterilizers should be tested with biological indicators at least once a week. A sterilizer used for several loads a day benefits from daily testing, which catches a malfunction sooner. A positive spore test, meaning spores survived, is rare; report it at once and follow the practice's procedure for affected loads.

Six entries on sterile items: shelf life, storage, opening a package, the unsafe zones of a field, adding items, and a constructed afternoon.

Sterile until something happens.

MAS 215 Event-Related Shelf Life

Many facilities treat a sterile package as sterile until an event contaminates it, rather than until a set date. Such events include a torn wrapper, a broken seal or a wet package; the more a package is handled, the more likely contamination becomes. Never use a sterile item whose package is wet, torn or punctured, or past a date the practice uses.

Dry, clean, off the floor.

MAS 216 Storing Sterile Supplies

Sterile supplies are stored where they stay dry and clean, never under sinks. Keep them off the floor, about eight to ten inches up, away from outside walls, and in closed or covered cabinets when possible; a sterile item that gets wet counts as contaminated. Inspect any package that falls on the floor before using it.

Away, sides, toward.

MAS 217 Opening a Sterile Package

A wrapped sterile kit is opened so your hands and body never pass over its contents. Set it on a clean, dry surface and check the wrapper and indicator. Open the first flap away from you, touching only its outer edge. Open each side flap with one hand, arm kept out from over the opened area. Open the last flap toward you without leaning over. To take something out, reach in with fingertips only, elbow raised. Do not let a corner flip back, because a corner that springs back over the field contaminates whatever it touches.

Edges, below, behind.

MAS 218 The Unsafe Zones of a Sterile Field

Some parts of a sterile field are always treated as contaminated. These include the outer inch around the edge, anything hanging below the tabletop, anything below your waist or above your shoulders, and any area you turned away from. When in doubt about whether something is still sterile, treat it as contaminated.

Drop, pour from the side.

MAS 219 Adding Items to a Sterile Field

Items are added to a sterile field without the wrapper touching the field. Peel a pouch open and drop the item from about six inches above the field; pour a sterile solution into a container from the side of the field, not over it. Put on sterile gloves away from the field, never over it.

A room turnover and a sterilizer load.

MAS 220 A Turnover and a Sterilizer Load

A constructed afternoon pays off the opening idea. After a minor skin procedure, the assistant gloves, handles sharps and waste, then sorts by risk. The instruments that entered skin are critical, so she rinses them at once to keep blood from drying. The cuff and table touched intact skin, so she disinfects them and leaves them wet for the label's contact time. Later she scrubs the instruments with hinges open, packs them with indicators inside and out, and loads the table-top sterilizer for steam to reach every pack. She checks the printout and each outside indicator, and as it is weekly testing day, she runs and logs a biological indicator. The printout says the machine ran, the indicators say packs met steam, and only the spore test says the process kills.

Look at what you can now do. You can tell cleaning, disinfection and sterilization apart, and you clean first every time. You can sort items into critical, semicritical and noncritical by how they are used, and leave a disinfectant wet for its contact time. You can explain steam sterilization and the three indicators that monitor it, and why only the spore test measures killing power. And you can store sterile supplies, open a sterile package and add items to a field without contaminating it. Unit Ten turns to workplace safety and emergencies.