GASPLASMASTERILIZATION Dr.T.V.Rao MD
Advances in Sterilization • Sterilization, as a specific discipline, has been with us for approximately 120 years, since the invention of the steam autoclave by Charles Chamberland in 1879.1 Since that time, we have seen progressive refinement in steam sterilizers: from the early, manually operated equipment to modern microprocessor-controlled, automatic machines. Although the efficiency, reliability, and performance monitoring of modern equipment is continually improving, the fundamental process remains essentially the same.
GAS PLASMA • Gas Plasma (vaporized hydrogen peroxide) is a relatively new option that can provide low heat sterility cycles with none of the off-gassing concerns present with EtO. Gas Plasma (VHP) sterilization has, until now, been exclusively used by large manufacturers as the end line process for in-house sterilization.
Beginning of Gas Plasma • Gas plasma sterilization technology based of Plasma was patented in 1987, and marketed in U S 1993.
What is Gas Plasma • Plasma is a fourth state of matter which is distinguishable from liquid, solid, or gas. In nature, plasma is widespread in outer space. • Gas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles
How Gas Plasma works. • Many particles are in the form of free radicals • A free radical is an Atom with an unpaired electron and is a highly reactive species • The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components, ie is enzymes and nucleic acids. And thereby disrupt the metabolism of microorganisms.
Identified Advantages • Materials and device compatibility • Rapid turnaround times • In-house control of the sterilization process • Lower inventory requirements.
Beneficial for sterilizing temperature-sensitive polymeric materials • The advantages of gas plasma sterilization include its ability to provide safe, non toxic, dry, low-temperature sterilization in about one hour. By-products of plasma sterilization are primarily water and oxygen. Because these by-products are harmless, there is no need for aeration or environmental hazard concerns.
Steps in Plasma sterilization • The Vacuum Phase • The chamber is evacuated, reducing internal pressure in preparation for the subsequent reaction. • The Injection Phase • A measured amount of liquid peroxide is injected into the chamber, evaporating the aqueous hydrogen peroxide solution and dispersing it into the chamber, where it kills bacteria on any surface it can reach.
The Diffusion Phase • The hydrogen peroxide vapour permeates the chamber, exposing all load surfaces to the sterilant and rapidly sterilizes devices and materials without leaving any toxic residues. At the completion of this phase, the chamber pressure is reduced and the plasma discharge is initiated.
The Plasma Phase • An electromagnetic field is created in which the hydrogen peroxide vapour breaks apart, producing a low-temperature plasma cloud that contains ultraviolet light and free radicals. Following the reaction, the activated components lose their high energy and recombine to form oxygen and water.Phases 1, 2, and 3 are then run a second time for added efficacy. This built-in reprocessing assures optimal sterilization for even the most difficult-to-sterilize devices.
The Vent Phase The chamber is vented to equalize the pressure enabling the chamber door to be opened. There is no need for aeration or cool-down. Devices are ready for immediate use.
Advantages of plasma sterilization • Low-Temperature Hydrogen Peroxide Gas Plasma (LTHPGP) has a number of advantages compared to established sterilization technologies. These include a short (one to four hours) sterilization cycle, low temperature and humidity, no aeration requirement, no toxic chemical residues or environmental impact, and broad compatibility with materials.
The Biological Indicator for quality control • The Biological indicator used with system is Bacillus atrophaeus spores.
Improvement to New technology • The newer version of unit, which employs a new vaporization system that removes most of the water from hydrogen peroxide, has a cycle time from 28-38 minutes.
Mode of Action in Gas plasma usage The process inactivates microorganisms primarily by the combined use of hydrogen peroxide gas and the generation of free radicals ( hydroxyl and hydroproxyl free radicals ) during the plasma phase of the cycle.
Uses of Gas Plasma • Materials and devices that cannot tolerate high temperatures and humidity such as some plastics, electrical devices, and corrosion- susceptible metal alloys, can be sterilized by hydrogen peroxide • This method proved compatible with most (>95%) medical devices and materials tested.
Gas Plasma Work Station • Medical instrumentation can be sterilized through a hydrogen peroxide gas plasma process with the Sterrad 100 system (Advanced Sterilization Products). Photo: Advanced Sterilization Products
Disadvantages • The disadvantages of gas plasma sterilization are that it may not penetrate well, especially in channels or devices designed with long lumens. In addition, the gas plasma sterilization method may corrode some materials and cannot be used on paper, cellulose or linen. An additional drawback to plasma sterilizers is their small chamber.
Acceptable Technology • According to experts, only a few disadvantages associated with gas plasma sterilization exist. These include the inability to process liquids, powders, or strong absorbers (cellulosics), and some lumen restrictions. Also, gas plasma sterilization is not recommended for liquids and other devices that can be damaged physically or changed by exposure to low pressure.
Hydrogen Peroxide Sterilization Offers Fast Cycle Times • Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times, the absence of toxic residuals, and a low-moisture environment not exceeding 50ºC, a
STERRAD TECHNOLOGY • In 1993, the STERRAD Technology received clearance and was introduced into the United States. It is now available in more than 60 countries throughout the world with over 6,000 units sold, making it the world's fastest growing sterilization technology.
STERRAD 100 • The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment.
The topic created as per guidelines for Disinfection and sterilization in Healthcare Facilities,2008CDC Dr.T.V.Rao MD Email email@example.com