With the increasing requirements for infection control in hospitals, the sterile supply centre (CSSD) has become the core department for performing the functions of recycling, cleaning, disinfection and sterilisation of medical equipment in hospitals as well as the logistics centre for the supply turnover of sterile equipment. Its construction is closely linked to hospital infection management and has a direct impact on the efficiency of hospital treatment.
According to the relevant regulations, the CSSD is divided into two main areas, namely the auxiliary area and the working area.

Working Area
A standard CSSD Centre requires at least 3 separate working areas: decontamination area,inspection of packaging&sterilization area and sterile area. There is a transition room between two adjacent areas. The flow of people and goods into and out of the supply room is strictly separated. Logistics can only go from the contaminated to the clean and then to the sterile area. The air flow goes from the sterile zone to the clean zone and then to the contaminated zone.

10 Procedures of the operational flow include:
Recycling → Sorting → Washing → Disinfection → Drying → Inspection and Maintenance → Packaging → Sterilisation → Storage → Distribution of Sterile Items

1. Contaminated Area
Reused medical instruments, apparatus and articles are collected, sorted, cleaned and disinfected in the CSSD. The area for recycling, sorting, cleaning, disinfection and drying (including cleaning and disinfection of delivery instruments, etc.).
The main equipment : Pure Water Machine, Ultrasonic Washer Disinfector, Medical Drying Machine, Washer Disinfector.
Contaminated items enter through the channel, are sorted, soaked and washed, and then passed to the cleaning area after washing, disinfection and drying by the washing machine.
(1) Pure Water Machine

Ensure the supply of hot water, soft water, purified water or distilled water to be used for cleaning of instruments. Purified water quality standard meets conductivity ≤ 15μS/cm (25℃).
The equipment is made of low carbon stainless steel, a material that does not pollute the water. For different users of high purity water different requirements, using reverse osmosis, EDI and other processes to meet the requirements of high purity water treatment process, no adsorption, non-polluting media. It is widely used in pharmaceutical plants and hospitals for purified water production and large infusion solution production.
The production should be able to meet the needs of CSSD equipment cleaning and sterilization, sterilization steam water meet the water standards.
(2) Ultrasonic Cleaning Machine
It carries the main cleaning tasks of the central supply room of the hospital, from the pre-washing of the instruments, to the ultrasonic cleaning, and then the ultrasonic cleaning and rinsing, and deals with the main cleaning links of the instruments. The cleaning degree is high and the workload of the personnel is reduced.

The vacuum boiling ultrasonic cleaning machine combines the spray cleaning machine, vacuum boiling cleaning, negative pressure ultrasonic cleaning, negative pressure pulsating cleaning, steam pretreatment, negative pressure hot air drying and other advanced technologies to provide a new solution for the cleaning of medical instruments. It can complete the washing, cleaning, rinsing, steam pretreatment, drying and other functions of medical instruments. Ultrasonic power conversion efficiency is high, cleaning speed is fast, than the traditional cleaning method of several times to dozens of times. Maximize the protection of the cleaned medical instruments from damage, can thoroughly clean all kinds of stains of surgical machinery and accessories, eliminate the problem of manual cleaning is not thorough, and protect the staff from contamination and infection.
(3) Endoscope Washer Disinfector
It is specially used for cleaning and disinfecting endoscopic instruments.

The endoscope cleaning and disinfection machine adopts microcomputer control, one-button start, high-pressure spray, automatic side leakage, cleaning, rinsing, disinfection, final washing, alcohol drying and air drying for each endoscope pipeline, realizing full immersion of the mirror body, and completing the process of washing in only 8-15 minutes, improving the utilization rate of the hospital endoscope turnover.
A wide range of applications: gastroscope, colonoscope, bronchoscope, otorhinolaryngoscope, biliary endoscope and other soft endoscope full immersion cleaning disinfection and other soft endoscope.
(4) Washer Disinfector
Mainly responsible for all kinds of equipment cleaning and disinfection, a complete set of equipment to complete the whole cleaning process. The significance of disinfection after cleaning is to further reduce the biological conformity on the instruments and appliances after cleaning and ensure the success of sterilization. No sterilization is a substitute for cleaning.

The whole cleaning process is automated, greatly reducing the intensity of manual labor, in order to meet the needs of the hospital supply center cleaning and disinfection. The equipment can be equipped with different cleaning racks to realize the cleaning and disinfection of various types of instruments, which is balanced and perfect in terms of function and reliability, and can adapt to the complex and diverse cleaning and disinfection environment.
(5) Medical Drying Cabinet
Complete bulk drying of most instruments.

Made of high quality stainless steel, low bacterial attachment rate, in line with the operating room, supply room requirements; And with insulation sandwich, effectively prevent heat loss; The door adopts large window hollow safety glass, which can effectively prevent heat loss and observe the internal working condition at any time. Indoor shelf can be adjusted with user requirements arbitrary height and the number of shelves; Reasonable air duct and circulation system, so that the temperature in the working room is uniform.
A variety of drying methods can be selected to meet the drying needs of the hospital without equipment, can be fully dried after cleaning products, no residue after drying.
2. Inspection of Packaging&Sterilization Area
Check the decontaminated medical instruments and articles in the CSSD. Assembly, packaging and sterilization (including dressing preparation, etc.).
The main equipment :Pulsating Vacuum Sterilizer, Low Temperature Sterilizer

(1) Pulsating Vacuum Sterilizer

The article is placed in the sterilization cabinet, the use of high pressure saturated steam to denature the protein and nucleic acid in the microbial body so as to kill microorganisms. The sterilization ability of this method is strong, the sterilization temperature is generally about 130℃, can achieve 99.9% sterilization effect. It is the most effective and widely used sterilization method in thermal sterilization.
Process:Pulsation – Heating – Sterilization – Exhaust – Drying – End
In a good sterilization effect at the same time, it is also the longest time to consume, usually, sterilization cycle cycle time is 1-3 hours, manpower and time consumption, so the sterilization center is generally used for the sterilization method for the end of the sterilization of articles.
Scope of application: buffer solution, culture medium, clean clothes, glassware, infectious dirt and other items that do not change or damage in high temperature and humidity.
Due to the diversification and refinement of surgical instruments, the traditional pressure steam sterilization method can not completely cover the sterilization of all kinds of medical instruments, so a variety of low temperature sterilization methods gradually emerged, and become one of the necessary sterilization methods in hospitals.
(2) ETO Sterilizer

Ethylene oxide (ETO) sterilization is suitable for sterilization of items sensitive to heat and humid heat and items that cannot be autoclaved. It can ensure to the greatest extent that medical instruments and medical supplies are not damaged in the sterilization process.
Scope of application: It is applied to all kinds of medical instruments which are not high temperature resistant, especially for sterilization of semi-rigid endoscope and flexible endoscope.
Process: Pretreatment (heating, humidification, pre-vacuum) – Dosing – Sterilization – Cleaning – Analysis (residue removal).
The sterilization process is stable, strong penetration, can go deep into complex instruments and long and narrow tubes, can complete other low temperature sterilization methods are difficult to achieve sterilization effect. Sterilized articles can generally be retained for 1-2 years. Compared with other sterilization methods, ethylene oxide sterilization cost is lower.
Ethylene oxide sterilization time is long, 100% pure ethylene oxide sterilizer action concentration is 450~1200mg/L, working time is about 6h. Therefore, it is suitable for sterilization of all departments of the hospital and most of the ordinary daily articles that do not need urgent use in the hospital.
At the same time, the final product of sterilization is ethylene oxide, which is toxic and suspected carcinogenic. After sterilization, it remains on the surface of articles, and can cause environmental air pollution, harmful to patients and medical staff.
(3) Low Temperature Sterilizer

Low temperature plasma sterilization equipment is mainly used for rapid sterilization of instruments afraid of heat and damp heat, in order to ensure the safety and efficiency of high value instruments. This is a new sterilization technology, because of its fast sterilization progress, non-toxic, environmental protection and gradually widely accepted by people.
Scope of application: Medical instruments sensitive to high temperature, radiation and chemical sterilizers, such as endoscope, cystoscope, foraminal scope and other high-precision instruments.
Process: Vacuum – Injection – Diffusion – Plasma state – Ventilation
The sterilization penetration is weak, and it is difficult to guarantee the sterilization effect of complex instruments. Hydrogen peroxide is also a strong oxidizer, especially corrosive to metal, rubber, plastic and other materials, but eventually will decompose into oxygen and water, no pollution to the environment, to ensure the safety of operators.
Compared with traditional high-temperature sterilization equipment, low-temperature plasma sterilizer has a shorter sterilization cycle, only 40-60min to complete sterilization, which is more suitable for sterilization of instruments in emergency operation and joint operation. This method can make the resource use of instruments reach the best state, and greatly improve the utilization rate and work efficiency of medical supplies and medical instruments.
The application of low temperature plasma sterilization equipment can not only reduce the burden of medical staff facing work hazards and environmental pollution, but also save a lot of sterilization costs for medical institutions.
Sterilization effect: Autoclave Steam Sterilization > Ethylene Oxide Sterilization > Low Temperature Plasma Hydrogen Peroxide Sterilization
Each of the three sterilization methods has its own disadvantages. Rational use of these three sterilization methods and strict operation in accordance with the specifications can meet the clinical needs and reduce the infection rate in hospitals.
3. Sterile Area
Sterile goods storage area, also known as sterile area, is mainly used for storing sterile goods.
The main equipment: Air Purifier, Sterile Goods Storage Rack, Sterile Goods Transport Cart.

(1) Air purifier

Sterile area is responsible for the storage of aseptic items, which requires the highest degree of air cleanliness. In order to prevent other areas from polluting the sterile area, it is necessary to use laminar flow purifier to eliminate formaldehyde, ammonia, benzene and other harmful gases, introduce fresh and clean air, and meet the requirements of temperature, humidity and cleanliness.
(2) Storage and Distribution
The sterilized articles should be classified and stored in the sterile articles storage area.
Clean items are transported through the transfer window and then stored in different items areas using sterile area carts. Clear separation regulations and clear content identification are required to facilitate management and distribution.
Auxiliary Area
The auxiliary area is the living area for medical staff, including: office, rest, dressing, duty and other functions.
Other
Each area cannot be directly connected. When entering the three areas of the work area through the auxiliary area, it is necessary to enter through the buffer room. The buffer room is equipped with a wash basin, automatic faucet, automatic hand sanitizer and hand dryer.

Conclusion:
The construction of CSSD should be scientific, normative, rational and applicable, so it is necessary to design from the overall layout, zoning, decoration and purification and other aspects, combined with equipment and personnel management needs, to create a modern CSSD, to provide high quality services for the hospital, promote the development of the hospital.
