IAHCSMM Central Service - Chapter 14 High-Temp Sterilization

Factors that impact sterilization effectiveness

-The type of microorganisms present -The design of the medical device -The number of microorganisms (bioburden) present -The amount and type of soil present; soil acts as a shield for microorganisms

Cooling time depends on

-Type of sterilizer used -Design of the device and packaging being sterilized -Temp and humidity of the room

Steam-Flush Pressure Pulse Sterilizers

-Use a repeated sequence of a steam flush and pressure pulse to remove air from the sterilizing chamber and processed materials -Air removal occurs above atmospheric pressure; no vacuum is required

Conditions Necessary for Effective Steam Sterilization

Contact Temperature Time Moisture

Temperature Condition

Gravity sterilization - 250F Dynamic Air removal - 270F - 275F

Bioburden

The number of microorganisms on a contaminated object; also called "bioload" or "microbial load"

Saturated Steam

Steam that contains the maximum amount of water vapor

Jacket

-CS departments typically use jacketed sterilizers. -The interior chamber walls of the sterilizer are heated by steam in the metal jacket; helps minimize the amount of condensation that forms when hot steam contacts the chamber -Jacket surrounds the sides, top, bottom of the vessels and steam circulates in this space to preheat the interior chamber walls -Outside of jacket is covered with insulation

Phases of a Saturated Steam Sterilization Cycl

-Conditioning - steam enters at the upper back portion of the sterilizer; air is displaced through the drain; pressure begins to rise, as does the steam temperature Exposure - After the desired temperature is reached, the sterilizer's control system begins timing the cycle's exposure phase Exhaust - After exposure phase, drain is opened and steam is removed through the discharge line; filtered air gradually reenters the chamber and the chamber returns to room pressure Drying - drying times are based on the device, packaging and the sterilizer's IFU

Tabletop Sterilizers

-Frequently used in clinics and dental offices -Use electricity to heat water into steam

Immediate Use Steam Sterilizers

-Located in ORs or surgical suite substerile rooms, L&D units and special procedure areas that perform invasive procedures; intended for emergencies, have little to no drying time

Thermostatic Trap

-Located in the drain line -The drain and the area surrounding it are the coolest areas in the sterilizer -A sensor in the chamber drain measures steam temp and automatically controls the flow of air and condensate from the sterilizing chamber

Advantages of Steam Sterilization

-Low cost -Rapid sterilization cycles -Relatively simple technology -Leaves no chemical residues or byproducts

Contact Condition

-Most common reason for failure Caused by: -Inadequate cleaning -Sets are too dense -Poor instrument positioning -Packages wrapped too tight -Loads are too crowded -Basin positioning -Clogged drain strainer -Mechanical malfunctions -Utility malfunctions

Causes of Wet Packs

-Packs were improperly prepared or loaded -heavy or dense instrument sets -Not using absorbent material to wick moisture between heavy metal (basins) -Textiles wrapped too tight -Items wrapped while still damp or moist -Gasket not intact -Clogged chamber drain screen etc.

Gauges and Controls

-Provide a visual and written record of sterilization conditions Printout contains : -Date and time the cycle began -Selected cycle parameters, such as type of cycle, sterilization temp and dry times -written record of actual cycle activities (temp, exposure times, pressure)

Dynamic Air Removal

-Similar to gravity air removal, except there is a vacuum pump or water ejector. -Usually operate at higher temperatures (270F-275F) than gravity. -Preconditioning phase increases the speed of operation and reduces the chance of air pockets. -Uses variations of prevacuum air removal and above-atmospheric-pressure processes, such as steam-flush pressure-pulse process (SFPP) -Effective air removal is critical for steam penetration

Gravity Air Displacement

-Small to medium-sized sterilizers have this. -Air is heavier than steam, the steam forces the cooler air to the bottom of the chamber and out the drain.

Prevacuum Steam Sterilizers

-The dynamic air removal cycle depends on one or more pressure and vacuum sequences at the beginning of the cycle to remove air during the preconditioning phase -Typical operating temperatures are 270F - 275F -Bowie Dick test should be processed daily to ensure proper air removal

Door, Gasket, and Chamber Drain

Door - weakest part of a steam sterilizer; has safety locking mechanism when pressurized and can only be unlocked after depressurizing Door Gasket- designed to maintain a tight seal to prevent steam from escaping the chamber and air entering the chamber Chamber Drain - located on the front center of the floor -Must be cleaned daily, debris can impede performance

Moisture

Dry, saturated steam is required for effective sterilization -Relative humidity should be 97% - 100% -Pressure must be increased to increase steam temperature

Time Condition

items within the load must be exposed to high temperatures for an adequate amount of time