steam sterilization

outer jacket chamber

Provides a reserve of steam to help maintain the temperature of main inner chamber. The steam heats the chamber walls and keeps them heated between cycles

gravity displacement caution

The size and loading of sterilizer can impede proces

sterilization or exposure

The sterilizer temperature is maintained for the amount of time required to destroy all microorganisms

testing - biological indicators

Uses non pathogenic spores -Used to test the effectiveness of the sterilizer bacillus stearothermophilus -Steam sterilizers Bacillus subtilus -ETO sterilizer

chamber

Where actual steam sterilization takes place

exhaust

after the exposure cycle, steam is removed from the chambe

relative size of the load

do not overload sterilizers (or underload)

Time needed

door open, items untouched for 15-60 minute

Dry cycle

jacket heat slowly re-vaporizes and remove moisture from the pack

denisty of the load

linen - 12 x 12 x 20 and 12 poundsinstrument sets - follow manufacture guidelines

steps loading

peel packs, wrapping, rigid containers

temperature

temperature is set at a level known to kill certain bacteria.

pressure

the sole purpose of pressure is to increase the temperature of the steam

inner chamber

where items are place and where sterilization occurs

phase I (Conditioning or Come Up)

- Air is removed, valve opens, steam enters. Pressure and temperature rise to pre-set values. Thermostat in drain line measures pre-set temperature. When reached, valve closes and the timer starts.

Phase IV (Drying)

- Begins when atmospheric pressure is reached within the chamber. The steam in the outer jacket keeps the chamber hot and drives the moisture from the packs and dries them. After drying, the alarm buzzes and door can be opened

Phase II (Sterilization or Exposure)

- Sterilizer maintains temperature by periodically removing cooled steam in the form of condensate through the drain and replacing it with fresh steam at the top. Process continues until sterilization time is complete

phase III (Exhaust or Come Down)

- When timer reaches the end of the sterilization cycle time, the steam valve is shut off, the drain open, and the steam is exhausted from the chambe

Pre-vacuum Cycles

-*Wrapped instruments -270 F4 min 28-30 psi -Wrapped instruments -275 F3 min 28-30 psi

gravity displacement cycles

-*Wrapped instruments -270F 15-25 min 27 psi -Wrapped instruments -250 F30 min 15 psi -Wrapped instruments -275 F10 min 30 PSI

gravity displacement parameters

-270-272 °F for 3-10 minutes at 27-30 psi -250-254°F for 15 minutes at 15-17psi -notice the time / temperature relationship

steam sterilization

-A vapor by heating water to its boiling point. -Boiling point of water is 212 F -*A temperature of 270 F is neededfor steam sterilization to be effective

important

-Air must be removed to allow steam penetration and proper sterilization! -The greatest single deterrent to sterilization is presence of air. -Why? -Because air will block the steam and not allow it to get to the items being sterilized.

how does steam sterilize things

-Based on direct steam contact with all surfaces including threads, fibers, or particles of porous material subjected to the sterilization process -Steam permeates and heats through a process of condensation. -example; metal instruments -Steam cannot permeate metal. -The coolness of the metal condenses the steam until the surface is heated to the temperature of the steam

safety door gasket

-Can withstand tremendous pressure - 6,000 lbs at 15 psi. -Has a locked safety door to protect against explosive openings

incomplete air elimination (Air blocks steam)

-Causes decreased temperature and blocks steam penetration -Prevents sterilization in the allotted time.

advantages of steam

-Destroys most resistant spores in a short time -Relatively rapid heating and penetrating of steam -Non toxic as opposed to Ethylene oxide

drying/cooling

-Exhaust -dry cycle -time needed -room parameter

types of steam sterilizers

-Gravity Displacement Sterilizer -Pre-vacuum Sterilizer (90%) (Called Dynamic Air Removal in your textbook) -Steam Flush Pressure Pulse (SFPP)Also called High Vac or Pulse Vac

time, temp, pressure relationship

-Instrumental in the destruction of microbes. -Time / Temperature -higher temperature = lower time Ex: 270°F for 3min -lower temperature = higher time Ex: 250 °F for 10 min

construction of a sterilizer

-Jacket Chamber -chamber

thermometer

-Located in the discharge line which is the last area to heat -Indicates temp in the coolestpart of the sterilize

loading

-No items should touch chamber walls -Instrument container systems and perforated or mesh-bottom trays are placed flat on the carrier shelf or sterilizer rack. -Container systems can only be stacked if this is documented by manufacturer. -Wrapped instrument trays should not be stacked

recording charts or tape

-Permanent Record that includes: -Temperature of sterilizer -Time at that temperature -Pressure of sterilizer -Total time of sterilization

typical Steam Sterilization Cycle:

-Phase I (Conditioning or Come Up) -phase II (Sterilization or Exposure) -phase III (Exhaust or Come Down) -Phase IV (Drying)

pressure alone

-Pressure alone has no microbicidal effect -Pressure is needed to increase the temperature of the steam -Pressure also enhances the deep penetration of steam as steam contact with all surfaces is essential

gravity displacement

-Principle -Air is heavier than steam. -Process -Steam enters from the top and displaces the air. -As the steam occupies more space it displaces the air out of the drain in the bottom front of sterilize

pre vacuum sterilizer (most common)

-Principle -All air is evacuated first, before steam is injected. This is a more efficient steam sterilizer -Design -2 chambers with a pump at bottom -Process -All air is removed for 8-10 minutes, steam is injected and replaces all air. -Caution -Size and loading less of a factor -Parameters; 270-276°F for 4 minutes at 27-30 psi. -example is like removing air from a ballon

jacket chamber

-Provides a reserve of steam to maintain temp in the main inner chamber. -Provides insulation for heat and drying

biological testing

-Spores placed into incubators and read by infrared sensors -Results should be negative -Positive results mean bacterial spores are growing and sterilizer has malfunctioned

how steam sterilization occurs

-Steam alone is inadequate for sterilization. -But when steam is contained in a closed compartment and its pressure increased, its temperature will increase as long as the volume of the compartment remains the same. -Pressure is added to increase the temperature of the steam.

heating or conditioning

-The time needed to bring the sterilizer to the preset temperature -Air is displaced, temperature and pressure is increased

how does a steam sterilizer destroy microbes?

-Uses Heat and Moisture -Heat and moisture combine to cause protein coagulation or denaturation. -Moisture acts as a catalyst to speed the reaction.

Immediate Use Steam Sterilization (IUSS)

-also known as "Flash Sterilization" -wrapped instrument placed into a special sterilization pan. ONLY USED IN OR IN CRITICAL SITUATIONS! -Performed during a surgical procedure when a vital instrument becomes contaminated

steam Flush Pressure Pulse (SFPP)

-also known as High Vac / Pulse Vac -Principle -Pulsing gravity displacement -Design -4 to 5 vacuum cycle -Process -Between each vacuum cycle, steam enters the chamber to aid in removing air

loading-critical

-as stated in earlier slidesIn addition, remember... -All instruments are in the open position -Stylettes should be removed from suctions -(Stylettes are wires used to remove blood clots from suctions)

limitations of steam

-incomplete air elimination (Air blocks steam) -loading-critical -density of the load -relative size of the load

super heated steam

-occurs when excess heat is applied to saturated steam. (Dries out the steam) -The result is moisture is driven from the steam leaving hot gas pockets -Causes charring which destroys linen and rubber goods *items must be heat and moisture resistant*

storage of items

-shelf life - Sterility is EVENT related -Storage areas -Restricted traffic area -Away from ventilation -Closed area -Mesh or wire containers -<80°F, 30-60% humidity, 10 air exchanges/hr -Shelving - top shelf at least 18" from ceiling, bottom 10" from floor.

valves

-steam supply valve -water valve -drain valve -Must know if you are going to run the sterilizer in manual operation

six stages of sterilization

1.Loading 2.Heating or Conditioning 3.Sterilization or Exposure 4.Drying / Cooling 5.Testing 6.Storage of items

gravity displacement design

2 steam chambers. -outer jacket chamber -Inner chamber

Room Parameter

68-75°F for minimum of one hour

Bacillus stearothermophilus (example of what we test for)

A highly resistant spore used to test steam sterilizers. -temperature - 250 F ( a known temperature to kill this spore) -Time - 2 minutes (the D value for this spore) -Pressure - 15-17 psi -*Sterilizers are set at 270 F at 4 minutes, 27-30ps

testing-chemical indicators

A strip treated with a dye that changes when exposed to the sterilization process. -*Indicates only that the conditions of sterilization have been met

preparation of Items for steam sterilization

All items - clean and dry -Basins - stacked with towels -Instruments - heavy on bottom, sharp edges down, instruments open. -Linen - always freshly laundered. Packs no larger than 12 x 12 x 20 and 12 pounds. -Powered surgical instruments - pre-vacuum cycle or STERRAD

time

D-Value - the amount of time required at any temperature to kill 90% of the microbes. -Sterilizers are then set to times beyond the D-Value