Sterilization Types & Control Presented By –(Group 2) Dr Narendra Nath Jena, Dr Sam Raj G, Dr Gowri Achuvath, Ms. HM Jasmine, Ms Shweta Dixit Reviewed By- Dr Vijay Agarwal, Dr Lallu Joseph, Dr Narayan Pendse, Dr CM Bhagat

Contents What is sterilization Types Steam ETO Hydrogen Peroxide Gas Plasma Other Methods Monitoring the Sterilization Process Administrative Controls Chemical Indicator Monitoring Biological Indicator Monitoring Mechanical Indicators

What is Sterilization Sterilization is defined as a process where all microbes are removed from a defined object, inclusive of bacterial endospores. Sterilization is needed on an everyday basis in order to promote health and eliminate the risk of contamination.

Types of Sterilization

High Temp Steam Sterilization Steam: Dry saturated steam and entrained water (dryness fraction ≥97%) Pressure: 15 psi serves as a means to obtain the high temperatures. Steam-sterilizing temperatures are 121°C (250°F) and 132°C (270°F). Time: Recognized minimum exposure periods for sterilization of wrapped healthcare supplies are 30 minutes at 121°C (250°F) & 15 psi in a gravity displacement sterilizer or 4 minutes at 132°C (270°C) & 30 psi in a prevacuum sterilizer

High Temp Steam Sterilization Types Of Steam Sterilizer Gravity, Prevacuum, Steam-flush Pressure-pulse or Flash Used For:-

Low-Temperature Sterilization Technologies <60°C EtO/EO – This method uses Ethylene Oxide gas to sterilize items that cannot withstand the high temperatures or humidity created using other methods. The four essential parameters (operational ranges) are: gas concentration (450 to 1200 mg/l); temperature (37 to 63°C); relative humidity (40 to 80%)(water molecules carry ETO to reactive sites); and exposure time (1 to 6 hours).

Low-Temperature Sterilization Technologies <60°C The basic ETO sterilization cycle consists of five stages (i.e., preconditioning and humidification, gas introduction, exposure, evacuation, and air washes) ETO gas mixtures: ETO-carbon dioxide (CO2) mixture consists of 8.5% ETO and 91.5% CO2. ETO-hydrochlorofluorocarbons (HCFC) 100% ETO

4

Hydrogen Peroxide Gas Plasma Chamber is evacuated and hydrogen peroxide solution is injected from a cassette and is vaporized in the sterilization chamber to a concentration of 6 mg/l. The hydrogen peroxide vapor diffuses through the chamber (50 minutes), exposes all surfaces of the load to the sterilant, and initiates the inactivation of microorganisms. An electrical field created by a radio frequency is applied to the chamber to create a gas plasma. Microbicidal free radicals (e.g., hydroxyl and hydroperoxyl) are generated in the plasma. Range of 37-44°c and has a cycle time of 75 minutes.

Other Sterilization Methods Ionizing Radiation. Dry-Heat Sterilizers. the static-air type and the forced-air type. Liquid Chemicals. Microwave. Glass Bead “Sterilizer”. Vaporized Hydrogen Peroxide (VHP). Ozone. Formaldehyde Steam. Low-temperature Gaseous chlorine dioxide.

Monitoring the Sterilization Process QAP Should include: Administrative Controls Chemical Indicator Monitoring Biological Indicator Monitoring Mechanical Indicators Continuing Education

Objectives of Monitoring the Sterilization Process Assure high probability of absence of microbes on processed items Detect failures as soon as possible Remove medical devices involved in failures before patient use Improve patient outcomes Control costs

Methods of Monitoring Mechanical Indicators Chemical Indicators Equipment control Chemical Indicators Exposure/Process control Pack control Biological Indicators Load control

Sterilization Process Monitors MECHANICAL STERILITY ASSURANCE COMBINED RESULTS CHEMICAL BIOLOGICAL

Mechanical Indicators show: what is happening in the chamber whether conditions are being met cycle, time, temperature and pressure Limitations: monitor one location in sterilizer do not monitor each pack or tray do not indicate sterility

Chemical Indicators (CI) monitor one or more of requirements -time, temp, and sterilant can be external and Internal give instant results indicate proper conditions for sterilization were present External: distinguish between processed & unprocessed Internal: Validates Steriliant penetration

Chemical Indicators

Biological Indicators Confirm the ability of the sterilization process to kill microbial spores Biological Indicators large number of spores Integrate all the parameters of the sterilization process Most critical test of the sterilization process

Biological Indicators Steam Sterilizer Test pack – includes BI containing Geobacillus stearothermophilus Placement - near drain in fully loaded sterilizer EO Test pack – includes BI containing Bacillus Subtilis Placement - centre of normally loaded sterilizer

Bowie Dick Type Tests Detects entrapped air in Vacuum- assisted sterilizers, not for Gravity Measures steam penetration Run daily Test packs – can be in-house or commercially prepared

Bowie Dick Test Run a warm-up cycle first Place test pack in an empty sterilizer over the drain 132C (270F) for 3.5 - 4 minutes Uniform colour change Retain in records

Bowie Dick Test Unprocessed Processed

Sterilization Process Routine Monitoring Chemical Indicator Bowie Dick Type Test External Internal CSA Recommends Daily Each package, tray, container

Sterilization Process Routine Monitoring Biological Indicator Steam Flash Ethylene Oxide CSA Recommends Daily; every load with an implantable device Daily; every load with an implantable device Every Load

Sterilization Process Monitors Record Keeping Document all materials that have been processed and the results of the sterilization process monitoring