Chapter 14: High Temperature Sterilization

What happens during the exhaust phase?

At the end of the exposure phase, the chambers drain is opened and the steam is removed through the discharge line. This creates a void in the chamber, filtered air is gradually re-introduced to the chamber and the chamber returns to room pressure

What happens during the drying phase?

Drying begins at the conclusion of the exhaust phase. Dry times are based on the device, packaging and the sterilizers IFU. At the end of this. The end of cycle sound chimes and the door may be opened

Steam sterilizer cycles

1. Conditioning 2. Exposure 3. Exhaust 4. Drying (in most cases)

What is the atmospheric room pressure at sea level?

14.7 pounds per square (psi) inch at room temperature

Superheated steam

A concern of steam sterilization. This team reaches higher temperatures than saturated steam and due to the lack of moisture it's a poor sterilant (less than 97% rh)

What happens during the conditioning phase?

After the desired temperature is reached, the sterilizer's control system begins timing the cycles exposure phase

How is high temperature sterilization achieved?

By subjecting items being processed to thermal energy from moist heat or dry heat. Steam is the most frequently used sterilant for devices not sensitive to moisture or heat

Causes of wet packs

Improperly prepped Loaded incorrectly Dense instrument sets Not using absorbent material especially for basin sets Packs wrapped to tightly Packs wrapped while the items are moist Problems with the sterilizer Clean area is too humid (exceeding 70%)

Pre-vacuum steam sterilizers

In the 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. Operates at temperatures of 270 to 275°F and (132 to 135°C). Requires to be checked daily by processing a Bowie Dick test

Why is steam sterilization the favorite in most healthcare facilities?

It has a successful record of safety, efficacy, reliability, speed, no chemical residue or byproduct, simplicity and low cost. By contrast dry heat sterilization is seldom used because of the required lengthy exposure times

What are the various components of steam sterilizers?

Jacket, door, gasket, chamber drain, chamber wall, baffle plate, thermostatic trap, gauges and control monitors

Immediate use steam sterilizers IUSS

Located in operating rooms or surgical suite sub sterile rooms. These are for emergency sterilization situations. They have little or no dry time therefore instruments must be used immediately after sterilization

What is the weakest component of a steam sterilizer?

The door

Bioburden

The number of micro organisms on a contaminated object. Also called bioload or microbial load

Steam-flush pressure-pulse sterilizers SFPP

These sterilizers use a repeated sequence of a steam flush and pressure pulse to remove Air from the chamber. Air removal occurs above atmospheric pressure so no vacuum is required

True or false. A device can be cleaned without sterilizing but sterilization cannot be achieved if a device has not been thoroughly cleaned.

True

True or false if there are several wet packs from one load, the entire load should be considered wet

True. When this happens document this lot of packs in order to pinpoint the root cause

What factors impact sterilization

Type of micro organisms present Design of the medical device, complex or simple Number of micro organisms present Amount of soil still present

What is the path that steam takes?

Steam comes from an external source and enters the jacket, travels through here into the chamber where it hits the baffle plate and is dispersed throughout the chamber. Cold air is pushed out of the chamber and flushed down the drain and through the thermostatic trap. A sensor in this trap will automatically open or close when it senses steam or air and reacts based on the cycle that it's in.

What happens in the conditioning phase?

Steam enters the sterilizer and cold air is displaced through the drain. As steam fills the chamber, pressure begins to rise as does the temperature

Saturated steam

Steam that contains the maximum amount of water vapor (97-100%)

Various types of steam sterilizers

Table top, cart loading, floor loading

What materials cannot be steam sterilize?

Oils, powders, cork and Wood

Extended sterilization cycles

Some complex instruments require longer cycles

What conditions are necessary for effective steam sterilization?

-Contact: the most common reason for sterilization failure -Temperature: must be certain temperatures (gravity sterilization is 250°F and dynamic a removal is 270 to 75°F) -Time: exposure must be for an adequate amount of time -Moisture: moisture content should be between 97 to 100%

Cleaning the sterilizer

Cool the chamber first and then check the drain and all of the gaskets and O-rings and valves

Dynamic air removal sterilizers

Similar to gravity air displacement sterilizers except there's a vacuum pump or water ejector. This removes air from the chamber more effectively during the preconditioning phase. Usually operate at higher temperatures then gravity air displacement sterilizers 270 to 275°F (132 to 135°C). The air removal system reduces the chance of air pockets

Gravity air displacement sterilizers

Small to medium sterilizers have gravity air displacement and dynamic air removal cycles. In these cycles, steam enters the chamber because air is heavier than steam and the steam forces the cold air out through the drain. These sterilizers have sophisticated controls and print outs for record keeping

How should text textile packs & pouches be positioned?

Standing up on their sides, perpendicular to the shelf