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Disinfection and Sterilisation

Practical Aspects

Disinfection and SterilisationCSSD : Central Sterile Supply Department

TSSU : Theatre Sterile Supply Unit

HSSU : Hospital Sterile Supply Unit

The idea of SSU was conceived in the late 1940’s and it began to catch on in the 1950’s in the UK. After a slow start in Ireland there is now a professional body and specialist

courses are available.

Disinfection and SterilisationFunctions of SSU: Rinsing Cleaning Drying Inspection and assembly Packaging Labelling Sterilisation Storage Distribution

Disinfection and SterilisationMain objectives of SSU: To provide medical and surgical equipment that is safe to

use. To maintain records of processes used and instruments

processed. To relieve the Nursing staff of these duties. To avoid duplication of expensive hospital equipment. To maintain an inventory of supplies and equipment. To provide a safe environment for patients and staff To keep up to date with developments and advances.


The SSU should:

assume total responsibility for processing hospital items. Maintain an educational programme in relation to certain

aspects of infection control. Maintain a cost effective programme of instrument

management.


Management Structure of the SSU:Head of Facility

CSSD Manager

Shift Supervisors

CSSD Personnel

Sterilisation

Methods: Chemicals Filtration (liquids and gases) Radiation Plasma Low temperature steam/formaldehyde Dry heat Moist heat

Sterilisation

Cleaning – First step of any process.

Chemicals: Limited use. Items not packed so don’t remain sterile.

Filtration: Again limited applications. Best suited for small scale laboratory use.

SterilisationOther low temperature options :

Low temperature steam and formaldehyde. Complex technology therefore maintenance an issue.

Ethylene Oxide: a dangerous chemical – toxic and explosive.

Plasma: Safe to use but has limitations esp. cost and inability to function in presence of cellulose

Sterilisation

Dry heat : High Temperatures for prolonged exposure time eg 160C for one hour Good for delicate instruments eg opthalmic surgery or high carbon steels eg dental burrs etc.

Serilisation

Moist heat. Saturated steam at raised pressure eg. 120c for 20 mins or 134c for 3.5 mins.

Depends on good supply of steam and regular maintenance of equipment.

Sterilisation

Testing and validation:

Biological testing for EO, LTSF and plasma.

Chemical testing eg colour changes in tape or indicators.

Radiometers

Physical temperature and pressure gauges for autoclaves.


Other options: Single use items. Purchased sterile packs. Contracted service.

Central facilities supplying many hospitals.

DisinfectionByline: A. Das, P. Ray, M. Sharma Dear Editor, Endoscopy is a very frequently performed diagnostic and therapeutic

interventional modality. Recently, it has been reported that up to 270,000 infections (in 2.7% of procedures) are transmitted annually by flexible endoscopes in the USA. There have been > 500 reports of infections due to use of contaminated endoscopes, commonly by Pseudomonas aeruginosa , Salmonella spp., Mycobacterium tuberculosis and atypical mycobacteria. Recommendations for reprocessing of endoscopes have been established worldwide, but lack of compliance is rampant in 20-70% of centres in Europe, Australia and Asia. Compliance is also very poor in Japan, India (only 1/3 of 133 centres practised minimum disinfection), Western Europe (inadequate disinfection in ≥30% centres) and USA (inadequate disinfection of 23.9% of endoscopes).

International recommendations for endoscope reprocessing is a stepwise process; pre-cleaning …

DisinfectionEndoscopy:There are many kinds of endoscope: Some of these require and can withstand sterilisation eg rigid

arthroscopes.

Others which are flexible and may have a number of lumens, such as bronchoscopes, colonoscopes, gastroscopes, duodenoscopes, and sigmoidoscopes require a high level of disinfection but cannot withstand sterilisation..

This involves thorough cleaning and exposure to a suitable chemical. At present this is usually peracetic acid. (Used to be glutaraldehyde. Newer agents include chlorine dioxide.)

Disinfection

Specialised endoscope washer/disinfectors.

Are enclosed to reduce noxious vapours. Can accommodate any scopes. Can flush out the different channels. Ensure sufficient contact time with disinfectant. Rinse with water. Should record both cycle and scope.

Disinfection

Endoscope Dryer/storage cabinets:

Once the endoscope has been disinfected it requires to be stored in a way so as to avoid contamination. Firstly, this means drying the scope and then storing it so that no microbes can reach it. Modern cabinets are designed to store scopes safely for up to 72 hours. Otherwise the scopes require retreatment