CENTRAL STERILE SUPPLY DEPARTMENT (CSSD)

The central sterile supply department (CSSD) becomes responsible for processing, sterilising and dispensing of almost all items of sterile equipment, sets and dressings in the hospital in one single department for efficiency and effectiveness.

Centralisation of sterilising activities in one department has resulted in many advantages. The chief among these are improved efficiency, sterile supplies available at all times of the day or night, economy of trained manpower, as it is no longer necessary for nurses to waste their time in sterilisation activities, sterilisation safety and quality control.

FUNCTIONS OF CSSD:

Broadly, the functions of the department are as follows.

1.       To receive and process used and unsterile supplies and sets from nursing units, OPD, operation theatres, labour rooms, etc.

2.       To sterilise and dispense sterile articles to user units.

3.       To maintain an uninterrupted supply of bacteriologically safe supplies at all times.

4.       To undertake studies for improvement of sterilisation practices and processing methods to provide supplies economically.

5.       To impart training to hospital personnel in safe hospital practices.

6.       To participate in hospital infection control programme.

7.       To advice hospital administration on suitability of supplies and equipment from sterilisation point of view.

STAFFING:

There should be a properly qualified supervisor in charge of the department. The chief of the department, the CSSD supervisor, has traditionally been a senior nurse. The supervisor can be a person from any other stream of hospital personnel provided he or she has a grounding in the basics of patient care. The other staffs required are usually in-service trained CSSD attendants, semiskilled workers who can be called CSSD assistants, CSSD technicians and sweeper.

A 200-bedded hospital with door delivery system to user departments would require 12 personnel, whereas a 500-bedded hospital has about 17 personnel. The number of workers will be influenced by the following:

1.       Method of collection and delivery.

2.       Quantum of work—one shift, two shifts, or one shift with only emergency issue counter after normal working time.

3.       Hospital’s philosophy on use of disposables.

4.       Availability of mechanical aids.

Flowchart of CSSD

EQUIPMENT:

The main item of equipment in the CSSD is the autoclave. At least one additional autoclave other than the main one should be provided to cater for failure or extra workload. Other equipment in the CSSD includes the following.

        ·         Dry oven

        ·         Gauze cutter

        ·         Ultrasound washer

        ·         Needle flushing device

        ·         Autoclaves

        ·         Ethylene oxide steriliser

        ·         Work benches with marble or stainless steel top

        ·         Storage cupboards and racks

        ·         Linen folding table

        ·         Soaking sinks

        ·         High pressure water jets.

Ultrasonic cleaner: One of the essential items of equipment in CSSD is the ultrasound cleaner. Ultrasonic cleaner cleans by bombarding the item with sound waves. These waves while passing through the detergent solution produce sub-microscopic bubbles which collapse on themselves, generating tiny shock waves that knock debris off nooks and corners of instruments that are not easy to reach.

POLICIES AND PROCEDURES:

Central sterile supply is most effective when it provides a limited basic range of articles for the greatest possible number of users. The list of items and special trays commonly processed in the CSSD are as follows.

        ·         Instruments

        ·         Appliances

        ·         Dressings

        ·         Sponges

        ·         OT linen

        ·         Special packs

        ·         Gauze and cotton materials

        ·         Gloves

        ·         Bowls and trays.

CSSD is one department where policies and procedures must be unambiguous and scrupulously followed in letter and spirit. The smallest mistake or carelessness on part of the staff can have serious repercussions elsewhere in the hospital. The policies should cover the following:

         1.       Responsibility: The responsibility for supervision of sterilising tasks should be clearly understood and vested under one person. Due to repetitive work, workers may be tempted to be careless in sterilisation procedures and differentiation between sterilised and unsterilized packs.

         2.       Disposables: The advantages and disadvantages of using disposables should be fully taken into account when considering the replacement of traditional materials by their disposable equivalents, remembering that some disposables give more value for money, while as some others have no specific advantages.

         3.       Segregation of Sterile and Unsterile Supplies: Sterile supplies and packs and contaminated articles should never be carried on the same trolley or by the same staff. The term “sterile supplies “covers all articles which have either been sterilised in CSSD or disposable sterile packs distributed through CSSD.

         4.       Standardisations of Packs: Special trays and sets to be processed by CSSD should be standardised by the hospital. In standardising, the aim is to have a standard surgical pack containing all the items required for that procedure by the operating personnel. This system has the advantage of having standardised sets ready at hand even for emergency operations, irrespective of special preferences of particular personnel.

         5.       Packing procedures: Step by step packing procedure for each pack should be determined, and should specify the quantities of materials required and their arrangement on the workbench, and the sequence of the packing operation.

         6.       Manual of operations: A procedure manual listing all procedures followed in the CSSD for each process and their correct sequence is essential for effective operation of the department. It must be realised that more costly and sophisticated the equipment, more training and precision is required to operate it.

         7.       Packing material: Packing material used as wraps for articles for sterilisation differs with the process of autoclaving or hot air oven. Linen and Kraft paper are commonly used, paper being a better bacterial barrier. The wrap should be easy to open without spilling the inside items. Articles for hot air sterilisation can be kept in suitable stainless steel containers. Syringes and needles are packed in paper wrappers. Gloves can be packed either in paper or linen.

AUTOCLAVING:

Use of saturated steam under pressure is the safest and dependable method of sterilisation, in universal use for destruction of all forms of microorganisms.

The minimum time and pressure for sterilisation by autoclaving process is 121°C at 15 lbs psi in 15 minutes. If the temperature is raised to 126°C, the time can be reduced to 10 minutes. At 134°C, it is 3 minutes, and only a minute at 150°C. The last process is utilised in “flash sterilisers” installed in some operation theatres for spot sterilisation of urgently required instruments during operation.

STERILITY INDICATORS:

          1.       Mechanical indicators are those which are monitoring instruments record time, temperature, humidity and pressure during the sterilisation cycle.

          2.       Chemical indicators are devices with a sensitive chemical or dye to monitor one or more parameters of a sterilisation cycle.

          3.       Biological indicators employ the principle of inhibition of growth of microorganism of high resistance to the mode of sterilisation. Subsequent failure of growth of microorganisms indicates adequacy of sterilisation.

No single method is capable of monitoring completely all parameters necessary for a fool-proof sterilisation.

         ·         Recording instruments on the autoclave which give a progressive graphic record of temperature, pressure, etc.

         ·         Chemical indicators change colour when conditions necessary for sterilisation have been met. These are available as tapes and strips.

         ·         To achieve a high degree of certainty that the autoclave is functioning properly, biological indicators should be placed in the most inaccessible location in the load and then cultured.

CHEMICAL STERILIZATION:

Ethylene oxide (EO) is a gas which is now commonly used as sterilising agent for heat-sensitive and moisture-sensitive materials like rubber, plastics and fibreglass. Effective sterilisation by EO depends upon the following:

          1.       Concentration of gas: 450 mg/litre or higher is essential for complete sterilisation.

          2.       Temperature: Exposure time can be reduced by increasing the temperature. Two temperature ranges are generally provided in the EO sterilisers 49° to 63°C and 30° to 37.8°C.

          3.       Humidity: In automatic sterilisers, steam is injected under vacuum before admitting the gas. In some a wet gauze or sponge is required to be placed. Other sterilisers depend on ambient humidity, and compensate for lower moisture by a higher exposure time.

          4.       Packing: The type of wrapping used should be penetrable by ethylene oxide and water vapour. Polyethylene is commonly used for loose wrapping.

          5.       Period of exposure: In automatic sterilisers, the time ranges from 110 to 260 minutes. Up to 12 hours may be required in others.

Ethylene oxide sterilisers generally fall into two categories-manually operated and automatic. The source of the gas is provided by large compressed gas cylinders or by a unit dose cartridge sufficient for one cycle. Simple sterilisers carry out sterilisation at room temperature and ambient humidity, with single-use glass ampoule of ethylene oxide seated inside a gas-release bag. On breaking, liquid ethylene oxide vaporises and diffuses out of the gas-release bag into a larger bag in which the material to be sterilised has been placed. This bag performs the function of diffusing chamber and allows the gas to retain long enough to achieve sterilisation.

Sterilisation Process: After the steriliser chamber is sealed and the controls set,sterilisation process goes through the following phases:

1.       Warming the chamber

2.       Evacuating residual air to partial vacuum

3.       Introduction of moisture to ensure that it penetrates wrappings and material

4.        Introduction of EO

5.       Raising the temperature (if required)

6.       Exposure for the required time

7.       Release of chamber pressure

8.       Removal of the gas under vacuum (called the “Purge cycle”)

9.       Re-establishment of atmospheric pressure by introduction of filtered air into chamber.

CSSD DISTRIBUTION SYSTEM:

Distribution system for sterile article should also be decided at the planning stage itself. The following four systems are in use. The last two are door deliveries.

            1.       Clean for dirty-exchange: A sterilised articles is issued at the CSSD issue counter on return of a used one at any time.

            2.       Requisition system: Articles needed are requisitioned by users on a daily or regular basis and collected by them at CSSD counter.

            3.       Grocery system: Each user’s requirements for all items for a specific period are delivered at suitable interval irrespective of whether the contents have been used or not and the previous basket or container withdrawn.

            4.       Quota system: Predetermined stock levels (quota) of various items for each user unit are maintained by delivery personnel from CSSD through regular deliveries.

The choice of system will ultimately be dependent on local circumstances. A combination of the systems may be more appropriate in most hospitals.

References:
Principles of Hospital Administration and Planning- BM Sakharkar