Ozone Sterilization

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HOSPITAL CLINICAL ENGR. & MANAGEMENT 

What is sterilization? Types of sterilization The Ozone molecule Ozone sterilization Standarts for ozone sterilization Ozone sterilization equipments

Content

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What is sterilization? A process intended to remove or destroy all

viable forms of microbial life, including bacterial spores.

Different than Disinfection. It is less lethal process than sterilization because it destroys most recognized pathogenic microorganisms, but not necessarily all microbial forms such as bacterial spores

Sterilizer: An agent that destroys or eliminates all forms of microbial life in the inanimate environment, including all forms of vegetative bacteria, bacterial spores, fungi, fungal spores, and viruses BM 500

Sterilization? Sterile: absence of all living organisms,

particularly microorganisms: bacteria yeasts molds viruses

Presence of even bacterium renders the component nonsterile

Do not be fooled by the looks: a shiny stainless steel could be nonsterile whereas a rusty nail could be sterile

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What is sterilization? The Sterile Processing Department (Central

Supply, or Sterile Supply as it is also known), comprises that service within the hospital in which medical/surgical supplies and equipment, both sterile and nonsterile, are cleaned, prepared, processed, stored, and issued for patient care.

As the number and variety of surgical procedures grew and the types of medical devices, equipment, and supplies proliferated, it became apparent that a centralized processing was needed for efficiency, economy, and patient safety. BM 500

Sterilization 4 Major areas to accomplish the functions:

decontamination, assembly and sterile processing, sterile storage, and distribution. decontamination area, reusable equipment, instruments,

and supplies are cleaned and decontaminated by means of manual or mechanical cleaning processes and chemical disinfection.

Clean items are received in the assembly and packaging area from the decontamination area and are then assembled

and prepared for issue, storage, or further processing After assembly or sterilization, items are transferred to the

sterile storage area until its time for them to be issued. Several major functions are carried out in the distribution area:

case cart preparation and delivery; exchange cart inventory, replenishment and delivery; telephone-order and requisition-

order filling; and, sometimes, patient care equipment delivery. BM 500

The Decontamination Process The Decontamination Process: Used supplies and

equipment should be collected and taken to the Decontamination Area in the Sterile Processing Department in a way that avoids contamination of personnel or any area of the hospital. Equipment should be covered and supplies should be moved in covered carts,

closed totes or containers, or closed plastic bags. Attire: Personnel working in the decontamination area should

wear protective clothing, which includes a scrub uniform covered by a moisture-resistant barrier, shoe covers, rubber or plastic gloves, and a hair covering. During manual cleaning processes, when splashing can occur, safety goggles and a face mask should

be worn. Sorting:sorting begins at the point of use. Handling of

contaminated items should be minimized unless the user of the device is already wearing full personal protective attire, such as following care in the operating room. In areas where workers are wearing no or minimal protective attire, sorting should consist only of removing disposable sharps and discarding other single-use items.

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The Decontamination Process Soaking this is necessary only if you have lumens or other

complex designs that are filled with debris or if the devices are

very bloody and cannot be rinsed or wiped at the point of use. Washing detergent - should be compatible with the materials in

the device and suited for the type of soil. Consult the recommendations from the device manufacturer

Inspection after cleaning, all instruments should undergo inspection before being packaged for reuse or storage. Box locks, serrations, and crevices should be critically inspected for

cleanliness

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Instruments with cutting edges such as scissors, rongeurs, chisels, curettes, etc., should be checked for sharpness. There should be no dull spots,

chips, or dents.

The Assembly and Packaging Process

After the instruments have been cleaned and inspected, they are typically assembled into sets or trays according to recipe cards

that detail instructions for assembling each set or tray. Instruments and other items that are prepared for sterilization

must be packaged so that their sterility can be maintained to the point of use. The materials and techniques used for packaging must allow the sterilant to contact the device during the sterilization process as well as to protect the device from contamination during storage and handling before it is used. The time between sterilization and use may range from a few minutes to several weeks to many months. The packaging material

selected must also permit the device to be removed aseptically. Textiles Nonwowens Pouch packaging Rigid container

systems

Types of Sterilization

Steam Ethylene Oxide Dry Heat Microwaves Formaldehyde Gas Hydrogen Peroxide Plasma Ozone Gas Lonizing Radiation

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The Ozone Molecule

Ozone or trioxygen (O3) is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic O2. Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of animals. The ozone layer in the upper atmosphere filters potentially damaging ultraviolet ligth from reaching the Earth's surface.

Most people can detect about 0.01 ppm in air. Exposure of 0.1 to 1 ppm produces headaches, burning eyes, and irritation to the respiratory passages.

At -112 °C, it forms a dark blue liquid. At temperatures below -193 °C, it forms a violet-black solid.

Ozone is diamagnetic, meaning that it will resist formation of a magnetic field and will decrease the energy stored in the field once the field is established.

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The Ozone Molecule

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Properties

Molecular formula

O3

Molar mass 47.998 g·mol−1

Appearance bluish colored gas

Density2.144 g/L (0 °C),

gas

Melting point 80.7 K, −192.5 °C

Boiling point161.3 K, −111.9

°C

Solubility in water0.105 g/100mL (0

°C)

Refractive index (nD) 1.2226 (liquid)

Ozone Sterilization

The method of generation generated on-site generated by passing dry air (or oxygen) through high

voltage electrodes (ozone generator) bubbled into the water to be treated.

Ozone colorless gas relatively unstable highly reactive

reacts with itself and with OH- in water

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Ozone Sterilization

Generation of Ozone

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Ozone Sterilization

Flow Diagram

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Principles of Ozone Formation

A high voltage is applied between two concentrically arranged electrodes. The electrodes are separated from each other by a dielectric and two discharge chambers, through which gas flows. Some of the oxygen molecules in the input gas break down in the electric field and immediately attach themselves to free oxygen molecules, forming ozone.

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Ozone Formation

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Ozone Sterilization Because ozone is very reactive, it is also unstable. It cannot

therefore be stored and has to be produced where and when it is needed. Ozone is produced from oxygen-containing gases in ozone generators by means of a silent electrical discharge. All industrial-scale ozone generators make use of this method.

The effectiveness of the ozone generation is related to a number of factors. Depending on the input gas, the strength of the electric field, cooling and the design of the ozone generator, ozone yields of 1 to 16 percent by weight can be achieved in the production gas.

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Ozone Reactivity

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Ozone Effectiveness

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Advantages and Disadvantages Advantages

Highly effective against all type of microbes Disadvantages

Unstable (must be produced on-site) High toxicity High chemical hazards Highly sensitive to inorganic and organic loads Formation of harmful disinfection by-products

(DBP’s) Highly complicated maintenance and operation Very expensive

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Advantages and Disadvantages Advantages

Highly effective against all type of microbes Used for moisture and heat-sensitive items. Ozone generated from Oxygen and water No aeration because no toxic by-producs

Disadvantages Unstable (must be produced on-site) High toxicity High chemical hazards Highly sensitive to inorganic and organic loads Formation of harmful disinfection by-products (DBP’s) Highly complicated maintenance and operation Very expensive

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Sample Sterizers In 2002, TSO3 Inc., licensed ozone

gasrelatedsterilization technology fromLynntech. The 125 L - Ozone Sterilizerdeveloped by TSO3 Inc., is marketed tohospital sterilization centers. This device

wasapproved for marketing by Health Canada

inMay 2002 and received FDA approval inSeptember 2003. The sterilizer is sold in

theUS through Skytron.

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Sample SterizersThe ozone is killing any bacteria,

viruses or mold spores that it contacts. With a half life of approximately 20 minutes, ozone then reverts back to pure oxygen.

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Advantages and Disadvantages In 2002, TSO3 Inc., licensed ozone

gasrelatedsterilization technology fromLynntech. The 125 L - Ozone Sterilizerdeveloped by TSO3 Inc., is marketed tohospital sterilization centers. This device

wasapproved for marketing by Health Canada

inMay 2002 and received FDA approval inSeptember 2003. The sterilizer is sold in

theUS through Skytron.

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Other Applications Industrial applications

aquaria, fish disease labs, and aquaculture cooling towers pharmaceuticals and integrated circuit

processing (ultra-pure water) pulp and paper industry

Gaseous sterilization cleaning and disinfection of healthcare textiles

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