Wet steam in an autoclave can be caused by the placement of cold instruments in a hot chamber.

include "_nav_tab.php";There are three methods of sterilization: steam sterilization (also known as "autoclaving" or "moist heat under pressure"), dry-heat sterilization (electric oven) and chemical ("cold") sterilization. Note that if your facility performs any procedures that involve contact with the bloodstream or tissues under the skin, you should have more than one method of sterilization available to use as a backup if your equipment breaks down, supplies run low or electricity is unavailable.

Here is review if the key sequences of events needed to perform different types of sterilization as well as high-level disinfection. The tips are adapted from the comprehensive free refresher course developed by EngenderHealth (writeOutLink("www.engenderhealth.org/ip/instrum/in11.html",1)). echo"

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echo"".strtoupper("Pre-sterilization wrapping.")."
"; Wrapping items before steam and dry-heat sterilization helps decrease the likelihood that they will be contaminated before use. To wrap instruments and other items for steam sterilization, use two layers of paper, newsprint, or muslin or cotton fabric. Do not use canvas for steam sterilization, since steam may not penetrate this material. When wrapping items for dry-heat sterilization, use foil, double-layered cotton, or muslin fabric.

• Step 1
  Place the instrument or other item in the center of the top wrapper. The wrapper should be positioned so that the points--not the flat edges--are at the top, bottom, and sides.
• Step 2
  Fold the bottom section of the top wrapper to the center, and fold back the point.
• Step 3
  Fold the left section to the center, and fold back the point.
• Step 4
  Fold the right section to the center, and fold back the point.
• Step 5
  Fold the top section to the center, and fold back the point.
  Step 6
  Fold the bottom section of the bottom wrapper to the center, and fold back the point.
• Step 7
  Fold the left section to the center, and fold back the point.
• Step 8
  Fold the right section to the center, and fold back the point.
• Step 9
  Fold the top section to the center, and fold back the point.
• Step 10
  Tuck the point under the right and left sections. Step 11
  Fasten the folds securely, using autoclave tape, if available.

echo"

".strtoupper("Autoclaving")."
";

• Step 1
  Decontaminate, clean, and dry all instruments and other items to be sterilized.
• Step 2
  Open or unlock all jointed instruments and other items, such as hemostats and scissors, and disassemble those with sliding or multiple parts. This allows steam to reach all surfaces of the item. Avoid arranging the instruments and other items together tightly, because this prevents steam from reaching all surfaces.
• Step 3
  Wrap the instruments.
• Step 4
  Arrange all packs, drums, or unwrapped items in the chamber of the autoclave in a way that allows steam to circulate freely.
• Step 5
  
  Note: The units of pressure marked on an autoclave's pressure gauge may vary from one autoclave to another. The following amounts of pressure (which are approximately equivalent) are the desired pressure for autoclaving:
  • 15 lb/in2 (15 pounds per square inch)
  • 106 kPa (106 kilopascals)
  • 1 atm (1 atmosphere)
  • 1 kgf/cm2 (1 kilogram of force per square centimeter)
  • 776 torr
  • 776 mm Hg (776 millimeters of mercury)
• Step 6
  If the autoclave is automatic, the heat will shut off and the pressure will begin to fall once the sterilization cycle is complete. If the autoclave is not automatic, turn off the heat or remove the autoclave from the heat source after 30 minutes if items are wrapped, 20 minutes if items are unwrapped. Wait until the pressure gauge reads "zero" to open the autoclave. Open the lid or door to allow the remaining steam to escape. Leave instrument packs or items in the autoclave until they dry completely, which could take up to 30 minutes. Note: Items must be removed dry. Once removed from the autoclave, damp packs draw microorganisms from the environment and should be considered contaminated
• Step 7
  Remove the packs, drums, or unwrapped items from the autoclave using sterile pickups. To prevent condensation after removing packs or drums from the autoclave, place them on a surface padded with sterile paper or fabric until they are cool. Wait until the packs, drums, or items reach room temperature (which may take up to several hours) before storing.
• Step 8
  Store items properly.

echo"

".strtoupper("Dry-heat sterilization")."
";

• Step 1
  
  Step 2
  Either 1) wrap the instruments and other items using foil, double-layered cotton, or muslin fabric; 2) put unwrapped instruments and other items on a tray or shelf; or 3) place instruments and other items in a metal, lidded container.
• Step 3
  Place instruments and other items in the oven, and heat to the designated temperature. The oven must have a thermometer or temperature gauge to make sure the designated temperature is reached.

  Use the list here to determine the appropriate sterilization times for instruments. The time reflects the length of time the instrument should be sterilized at the corresponding temperature.

  • 170' C (340' F) — 1 hour
  • 160' C (320' F) — 2 hours
  • 150' C (300' F) — 2.5 hours
  • 140' C (285' F) — 3 hours

  Note: Because dry heat can dull sharp instruments and needles, these items should not be sterilized at temperatures higher than 160' C.

• Step 4
  Leave items in the oven to cool before removing. When they are cool, remove items using sterile pickups and use or store immediately.
• Step 5
  Store items properly.

echo"

".strtoupper("Chemical ("cold") sterilization")."
"; Chemical sterilization is used for instruments and other items that are heat-sensitive or when methods that require heat are unavailable. Items are sterilized by soaking them in a particular chemical solution (such as one containing glutaraldehyde) followed by rinsing them in sterile water.

DO NOT USE THESE SOLUTIONS FOR HIGH-LEVEL DISINFECTION

Hydrogen peroxide (6%). Hydrogen peroxide rapidly loses effectiveness when exposed to heat and light and requires careful storage. In addition, this solution may cause corrosion, which may damage laparoscopes and metal, rubber, and plastic items. Formaldehyde. This potentially cancer-causing solution is extremely irritating to the skin, eyes and respiratory tract. Alcohol (60-90% ethyl or isopropyl). Although effective against a wide range of microorganisms, alcohol does not kill all viruses. Iodophors. The most commonly available iodophors are antiseptic preparations, which are not suitable for disinfection. They are not recommended because their low levels of iodine allow them to become contaminated with microorganisms. Sporicidin. This glutaraldehyde-based product also contains phenol. In the past, it was available in many parts of the world. However, testing revealed it to be ineffective for chemical HLD and sterilization. Antiseptics. should never be used for HLD. They are for use on the skin, not on objects. Low-level disinfectants should never be used for HLD, because they don't have sufficient killing power.

• Step 1
  Decontaminate, clean, and thoroughly dry all instruments and other items to be sterilized. Water from wet items will dilute the chemical solution, thereby reducing its effectiveness.
• Step 2
  Prepare the glutaraldehyde (or other chemical solution) by following the manufacturer's instructions--or use a solution that was prepared previously, as long as it is clear (not cloudy) and has not expired. After preparing the solution, put it in a clean container with a lid. Always mark the container with the date the solution was prepared and the date it expires.

  Note: Most commercially available glutaraldehyde solutions can be used for at least two weeks after preparation. Follow the manufacturer's instructions. Ideally, an indicator strip should be used each time the solution is to be used to determine if the solution is still effective.

• Step 3
  Open all hinged instruments and other items and disassemble those with sliding or multiple parts. The solution must contact all surfaces in order for sterilization to be achieved. Completely submerge all instruments and other items in the solution. All parts of the items should be under the surface of the solution. Place any bowls and containers upright, not upside-down, and fill with the solution.
• Step 4
  Follow the manufacturer's instructions regarding the time necessary for sterilization. In general, if the solution contains glutaraldehyde, cover the container and allow the instruments and other items to soak for at least 10 hours. Do not add or remove any items to the solution once timing has begun.
• Step 5
  Remove the items from the solution using large, sterile pickups.
• Step 6
  Rinse thoroughly with sterile water to remove the residue that chemical sterilants leave on items. This residue is toxic to the skin and tissues.

  Note: Boiled water is not sterile; boiling does not guarantee that bacterial endospores have been killed.

• Step 7
  Store items properly.

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".strtoupper("High-level disinfection (HLD)")."
"; When sterilization is not available or feasible, high-level disinfection (HLD) becomes the third step in instrument processing. HLD is not the same thing as sterilization. HLD eliminates bacteria, viruses, fungi and parasites - but does not reliably kill all bacterial endospores, which cause diseases such as tetanus and gas gangrene. HLD is suitable for items that will come in contact with broken skin or intact mucous membranes.

Many facilities use a method of HLD as a backup to their primary method of sterilization. There are three methods of HLD: boiling, chemical HLD and steaming.

• Boiling. Boiling is a simple method of HLD that can be performed in any location that has access to clean water and a heat source. Using this method, instruments and other items are placed in a pot or boiler and the water is heated to boiling for 20 minutes.
• Chemical HLD. Chemical HLD, like chemical sterilization, is used for heat-sensitive items, like laparoscopes, or when a heat source is not available. Chemical HLD is different because: —Either glutaraldehyde or chlorine may be used for HLD. (Chlorine cannot be used for sterilization or for HLD of laparoscopes or other endoscopes.) —The soaking time is shorter for HLD —HLD items may be rinsed with boiled water. (Sterilized items must be rinsed with sterile water.) —In most settings, the only chemicals appropriate for HLD are chlorine and glutaraldehyde. Never use alcohol, carbolic acid (such as Lysol, Phenol), chlorhexidine gluconate with cetrimide (such as Savlon), chlorhexidine gluconate (such as Hibitane, Hibiscrub), chloroxylenol (such as Dettol), hydrogen peroxide or iodophors (such as Betadine).
• Steaming. Items are steamed in a steamer containing one to three tiers. Steaming is the best method of HLD for gloves, and is a useful method of HLD for the cannulae used during manual vacuum aspiration (MVA). Although MVA cannulae may be processed by other methods, HLD of gloves by other methods is less appropriate because: —Gloves may be HLD by boiling, but this is not recommended, since it is difficult to dry gloves properly without contaminating them. If it is necessary to HLD gloves by boiling, the gloves may be worn wet —Using chemicals to HLD gloves is impractical since it is difficult to adequately rinse off the chemical residue.

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".strtoupper("Common high-level disinfectants")."
"; The two chemicals most commonly available in most low-resource settings that are suitable for HLD of instruments and other items are chlorine and glutaraldehyde.

• Chlorine. Effective against a broad range of microorganisms, including tuberculosis-causing microorganisms. Does not necessarily kill all bacterial endospores. —Advantages: Fast-acting; usually inexpensive. —Disadvantages: Can be corrosive to metals with prolonged contact (more than 20 minutes) can be irritating to the skin, eyes, and respiratory tract; should not be used on endoscopic equipment.

• Glutaraldehyde (Cidex, for example). Effective against a broad range of microorganisms, including tuberculosis-causing microorganisms. Soaking for 10 hours can kill bacterial endospores. —Advantages: Not corrosive to instruments and other items when used as directed. —Disadvantages: Irritating to the skin, eyes, and respiratory tract. When handling glutaraldehyde, wear gloves, prepare the solution in a well-ventilated space, and limit exposure to the chemical.

What steam in an autoclave can be caused by the placement of cold instruments in a hot chamber?

What happens when a sterile field gets wet?

What causes damp autoclave paper?

Which of the following may cause incomplete autoclave sterilization?