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Healthcare facilities follow strict hygiene requirements, particularly in surgical departments. Sterilising surgical instruments is an essential part of this work. The procedure is intended to eliminate microorganisms and infectious agents from appropriately prepared instruments. Effective processing helps reduce the risk of infection and supports a patient’s recovery after surgery.
Stages and Methods of Sterilisation
Instrument processing involves three stages: disinfection, pre-sterilisation cleaning and sterilisation. Diagnostic devices that have contacted a patient’s mucous membranes and could damage them also require appropriate processing. Contact with intact mucous membranes generally requires at least high-level disinfection, while devices entering normally sterile tissue must be sterilised. Items that have come into contact with wounds or blood must be processed too. Sterilisation is carried out in a device known as a steriliser, using a method suitable for the item.
Surgical instruments can be sterilised using radiation, chemical agents or heat. The method is selected according to the characteristics of the items being processed. Some products cannot withstand high temperatures or contact with certain chemicals. The main approaches described below are:
- Chemical sterilisation. Three methods are discussed: ozone, plasma and ethylene oxide. Ozone sterilisation works through oxidation. It is designed to decontaminate exposed surfaces, with cycle duration determined by the validated system. Ozone is produced from oxygen. Ethylene oxide is used for gas sterilisation and is a low-temperature method, with operating temperatures commonly around 37–63°C. A basic cycle may take approximately 2.5 hours, excluding aeration. Items must be fully aerated before patient use to remove residual ethylene oxide. Plasma sterilisation is another option for compatible items requiring low-temperature processing. The validated manufacturer’s instructions determine the actual cycle parameters.
- Thermal sterilisation. Hot-air processing is carried out in specialised dry-heat sterilisers with preset operating cycles. Heat damages microbial proteins and inactivates microorganisms. Dry-heat sterilisation is an alternative to autoclaving for materials that cannot tolerate contact with steam but are compatible with dry heat. Steam systems are also used for suitable surgical instruments and suture materials. Microwave treatment has also been investigated, but short experimental cycles must not be treated as established instructions for sterilising surgical instruments.
- Radiation sterilisation. This method is used for various medical products, including certain surgical and dental instruments. Ionising radiation damages the DNA of microorganisms. Treatment time and suitability depend on the product and the validated process; it is not a universal replacement for autoclaving or dry-heat sterilisation.
Choosing a Suitable Method
The choice of processing method depends on the materials and construction of the instruments used for surgical procedures. Many endoscopic accessories are sensitive to high temperatures and steam, so they require an appropriate low-temperature process. Conventional steel instruments may be compatible with several methods, but the instrument and steriliser manufacturers’ instructions determine which can be used.
Processing time also matters. Dentistry often requires instruments to be ready promptly, making suitably validated rapid sterilisation systems relevant. Reports of rapid microwave processing do not establish its suitability for routine dental instrument sterilisation. Hospitals with planned operations and sufficient stocks of prepared materials and instruments may use more traditional steam systems. These can be affordable, economical and straightforward to operate. When choosing processing equipment, consult a specialist and consider the capacity of the device as well as its suitability for the required workload.
Source: Original Russian article on surgical instrument sterilisation
