Disinfection Methods of Medical Devices

Sterilization refers to the killing or removal of all microorganisms on objects, including bacterial spores with strong resistance, not only bacteria, but also viruses, fungi, mycoplasma, chlamydia and so on. Disinfection refers to the killing of pathogenic microorganisms on objects, that is, microorganisms that can cause disease. Bacterial spores and non pathogenic microorganisms may still survive. For the medical devices in the hospital, such as haemostatic forceps, microvascular instrument set, rumex instruments, etc., different disinfection and sterilization methods should be selected according to their properties.

 

 

1. Difference between Disinfection and Sterilization

The methods and principles of disinfection and sterilization are different.

 

(1) First of All, the Treatment Levels the Two Require Are Different

Disinfection only requires places and articles to reach harmless level, while sterilization requires that there is no viable bacteria.

 

(2) Secondly, the treatment methods the two select are different

Compared with disinfection, sterilization have higher requirements and is more difficult to handle. The physical method or chemical disinfectant that can kill the most resistant microorganism (bacterial spore) must be selected for sterilization, while the physical method, chemical disinfectant or biological disinfectant with certain germicidal efficacy should be selected for disinfection.

 

(3) Finally, the Place of Application Is Different from the Items handled

Sterilization is mainly applied for the treatment of diagnostic and therapeutic articles that enter into aseptic tissues and organs of human body and industrial products that need to be sterilized. Disinfection is to deal with articles in daily life and workplace, as well as general places and articles in hospitals, including surgical steel scissors, reduction forceps, etc.

 

 

2. Types of Disinfection

According to the level of disinfection, the disinfection of medical instruments can be divided into high-level disinfection, medium-level disinfection and low-level disinfection.

 

(1) High-level Disinfection

High level disinfection refers to the killing of all bacterial propagules, including mycobacteria, viruses, fungi and their spores, and the vast majority of bacterial spores. Generally, chlorine containing preparations, chlorine dioxide, o-phthalaldehyde, peracetic acid, hydrogen peroxide, ozone, iodine tincture and other chemical disinfectants that can achieve sterilization effect are usually adopted to disinfect with appropriate concentration and effective action time under specified conditions.

(2) Medium-level Disinfection

Medium-level disinfection refers to killing all kinds of pathogenic microorganisms except bacterial spores, including mycobacteria. Iodine disinfectant (iodophor, chlorhexidine iodine, etc.), compound of alcohol and chlorhexidine iodine, compound of alcohol and quaternary ammonium salt, phenol and other disinfectants were adopted to disinfect under the specified conditions with appropriate concentration and effective action time. The equipment for medium-level disinfection refers to the articles that contact with intact mucosa, but not enter into sterile tissues, organs and blood flow of human body, and also do not contact with damaged skin and damaged mucosa, such as gastrointestinal endoscopy, eye speculum, laryngoscope, nasal speculum, ventilator pipe, anesthesia machine pipe, different types of oxygen cannulas, tongue depressor, etc.

 

(3) Low-level Disinfection

Low-level disinfection refers to the chemical disinfection methods which can kill bacterial propagation (except mycobacteria) and lipophilic viruses, and mechanical sterilization methods such as ventilation and washing. For example, quaternary ammonium salt disinfectant (benzalkonium bromide, etc.) and biguanidine disinfectant (chlorhexidine) are adopted to disinfect under the specified conditions with appropriate concentration and effective action time. The objects of low-level disinfection or cleaning treatment refer to the equipment that contact with intact skin but not with mucous membrane, such as medical tape scissors, nurses dressing scissors, stethoscope, sphygmomanometer cuff, bed fence, bed surface, bedside table, bedding, wall, etc.

 

 

3. Sterilization Methods of Medical Devices

The general sterilization methods of medical devices include the following.

 

(1) Damp Heat Sterilization

Hygrothermal sterilization can be divided into high pressure, normal pressure, intermittent sterilization and pasteurization. Especially high pressure steam sterilization is widely applied.

 

(2) Dry Heat Sterilization

 

(3) Ethylene Oxide Sterilization

 

(4) Radiation Sterilization

 

(5) Low Temperature Plasma Sterilization

 

In short, specific disinfection and sterilization methods should be chosen according to different types of medical devices in practice.