According to the Center for Disease control and prevention, CDC, sterilization refers to the use of a physical or chemical procedure to destroy all microbial life, including highly resistant bacterial endospores’. Apart from the traditional sterilization methods, advancement in technology in medical equipment and procedures has brought about the need for advanced sterilization methods in the medical field. Currently, there are numerous sterilization methods available in the market and all vary depending on the nature of the devices or equipment. The following guide will provide the various methods of medical devices sterilization.
Firstly it is important to note that sterilization should not be used interchangeably with disinfection, because unlike sterilization, disinfection only destroys specific pathogens. Sterilization can be categorized into 3 i.e. chemical, radiation and high temperature/ pressure or autoclave sterilization. The following are some of the medical devices sterilization methods per category.
High temperature/pressure sterilization or Autoclave method
The cheapest and most common sterilization method available in the market. It simply works by filling a container known as an autoclave with items to be sterilized then sealing it and high temperature and pressure steam passed through it for a given period of time, killing the microorganisms in the items. However, this method is only suitable for devices that can tolerate high levels of pressure, temperature, and humidity.
Ethylene Oxide (EtO) Gas
EtO is a chemical sterilization agent effective in destroying microorganisms including spores. The sterilization occurs when EtO makes contact with the microorganisms on the device to be sterilized. Because of its highly flammable nature, it should be used only in the special sterilization chamber to prevent any explosions. After sterilization, the device must be properly aerated to make it safe for use. Devices that can be sterilized by this method include devices that are sensitive to heat and moisture.
Low-temperature hydrogen peroxides plasma
This is a sterilization system which works by combining hydrogen peroxide and low temperature gas plasma (ionized gas) to sterilize devices and equipment. It is a safer method of sterilization because it does not leave any toxic residue on the device unlike EtO gas. This method has two phases i.e. vacuum phase which involves plasma generation and sterilization phase which involves the actual sterilization process. This system is suitable for heat-sensitive equipment such as endoscopic devices.
Vaporized hydrogen peroxide (VHP) sterilization
In this method, the VHP sterilizer is filled with the devices to be sterilized then it follows the three-stage cycle of vacuum generation, hydrogen peroxide injection and aeration. Because of its low temperature process, VHP method is suitable for devices which cannot sustain high temperatures such as electronic devices.
Radiation sterilization method.
The objects to be sterilized are placed on a conveyer which passes each of them through a strong active gamma radiation until all the items have been sterilized. The gamma radiation causes ionization and formation of radicals which in turn destroy the living cell components of the microorganisms.
Electron beam or cathode ray sterilization
Just like the gamma radiation method, the devices to be sterilized are placed on a conveyer which transports them through a passage where the electron beam generator electron beams which penetrate the item, killing any pathogens present hence sterilizing it.
The above methods are only a sample of the most common techniques used. The application of the methods may vary depending on the need i.e., the nature of the medical equipment and the nature of the microorganisms to be destroyed. Therefore, when sourcing for the best sterilization method, it is best to give great consideration to the compatibility of the method and the medical equipment to avoid any potential damages.