Decontamination renders an article safe for handling; disinfection is used to reduce the number of microorganisms and; sterilization means the removal of all microorganisms.
Sterilization - heat sterilization is the cheapest, safest, and the most effective method of sterilization. Cold sterilization should only be used on heat-sensitive items such as endoscopes. The only reliable method of cold sterilization is prolonged exposure to 2% glutaraldehyde, although this can become inactivated under adverse conditions.
Disinfection - disinfectants should be used according to instructions at the optimum dilution. Some disinfectants may be rapidly inactivated by organic matter, therefore any object that is to be disinfected should be cleaned thoroughly with warm water and detergent prior to disinfection. Sustained-action disinfectant should be used for hand hygiene by staff and for cleaning the skin and mucous membranes of patients. Alcohol preparations over 40% are no recommended because of the risk of fire when use in conjunction with diathermy. In general, hard surfaces do not require disinfectants - warm water with detergent is usually sufficient to remove all organic contamination. The exceptions are where persistence of potentially dangerous pathogens, such as HIV or HBV is suspected, when the surface should be wiped by a disinfectant afterwards.
Certain rules should be followed when using disinfectants. The manufacturer’s instructions should be followed. The expiry date should be checked and the optimum dilution used. Articles to be disinfected should be washed and clean before disinfection. The disinfectant container should not be refilled without sterilizing between each use and not be topped up. Disinfectants should be supplied ready for use from the pharmacy and empty containers should be returned to the pharmacy Empty containers should not be discarded or used to store any other solutions as this is potentially dangerous. Open containers of disinfectant should not be tolerated as there is a serious risk of contamination with multiple antibiotic-resistant bacteria, such as Pseudomonas species and spores. When disinfectants are indicated for use on surfaces, they should be applied by wiping rather than bathing as bathing wastes disinfectants.
All hospital waste should be disposed of so that it presents no risk of injury or contamination. Clinical waste is generated during routine patent care and surgery. It is potentially dangerous and should be clearly labelled as high risk. Examples of clinical waste include dressings, body fluids, pathology waste, iv needles and syringes, drainage bags etc. Laboratory waste should also come under the high risk category and should be autoclaved before leaving the department and labelled biohazard. Other hospital waste include non-clinical waste and kitchen waste. The latter should be disposed of properly because it is a potential source of pests and vermin and thus may pose an indirect threat to the hospital. Provision must also be made for the safe disposal of radioactive waste. A simple colour-coding system should be used to separate waste so that the different components can be treated safely. The UK has a national colour-coding system ie. clinical - yellow, non-clinical - black, soiled laundry - red, dirty laundry - white, theatre laundry - green/blue. In the kitchen, different coloured gloves are used for cooking and cleaning equipment. In general, non-clinical waste is taken to a compactor and clinical waste to an incinerator or if not possible, to a lime-pit. Under no circumstances should clinical waste, needles or syringes be sent to the municipal dump. All staff handling clinical waste should be adequately trained especially with regards for the protocol of action in case of accidents. All staff must be provided with adequate protective clothing and replacement garments. Hepatitis B immunization should be offered to all staff and proper records kept for such immunization.
It is totally unjustified to recycle needles and syringes. Broken glass should be included in the sharps category. To dispose safely of broken glass, thick gloves should be worn and the pieces collected with a newspaper. The glass is then wrapped securely in the paper and either disposed of into the sharps container or if not practicable, into a cardbox box which is then marked and sealed. Sharps containers used in the UK must comply with BS89/52770, they must be leak and puncture-proof. Have a handle that allows lifting, a non-reopenable lid, and carry a biohazard sign. They should be sealed and replaced when it is no more than two-thirds full. Sharps containers are treated as clinical waste and should be put into clinical waste bags before being incinerated. In the event of an inoculation or contamination accident, it must be documented by the senior manager and reported to the Occupational health department and the Infection Control Team so that appropriate action can be taken. In the UK, all injuries must be recorded in an accident book. There must be clearly defined policy on the action to be taken after the injury and all staff should be aware of the policy.
Sterile Services and Recycling
A sterile services department (SSD) is vital for an effective infection program. Most hospitals in developed countries have a SSD to deal to deal with hospital and community services and a Theatre Sterile Services Unit (TSSU) to deal with the operating theatres and associated departments. However, hospitals in developing countries do not have the funds to run two separate departments. Dirty, recyclable equipment should be collected from the wards and transferred to the SSD, where it is washed, inspected, sterilized, packed, and dispatched back to the wards.
Workflow of the SSD - in the ward, dirty re-usable instruments are collected and put into clearly labelled containers and delivered to the SSD. Cotton wools and dressing should be discarded as clinical waste for incineration. The dirty instruments are then received in the dirty area of the SSD. All equipment is first washed in hot water and detergent either mechanically or manually. Manual washing requires the use of appropriate protective clothing such as heavy-duty gloves, plastic aprons, and eye-protection. The equipment is then inspected for cleanliness and damage. Instruments are then packed into individual trays for ward use and autoclaved and/or disinfected as required. The packaged trays are then inspected to ensure that they are dry and then sorted for ward collection. The sterile packs should be stored in well-ventilated rooms ready for dispatch to the wards. Collections should be regular and there should be a written record of receipt and delivery.
SSD staff facilities - all staff in the SSD should be provided with adequate protective clothing (eg. heavy duty gloves, plastic aprons, and eye-protection if manual washing is undertaken). Overshoes and masks are not necessary. All SSD staff should be immunized against hepatitis B and records kept by the Occupational Health Department. All staff should receive formal training and lectures on the prevention of sharps injuries and the procedure to follow should an accident occur. There should be policies for handling sharps, inoculation accidents, spillage of body fluids, and accidental splashing with reagents used in the SSD. Adequate changing, rest, and handwash facilities should be provided.
All equipment should be cleaned in the SSD. Equipment requiring sterilization must be cleaned thoroughly before the sterilization/disinfection process. For heavily contaminated equipment, it is not recommended that they be autoclaved before cleaning since it poses the problem of baked-on dirt.
1. Mechanical cleaning - most modern SSDs are automated and there is minimum handling of dirty equipment by staff. The equipment is placed in trays read for washing. The following machines are usually available;-
2. Manual Cleaning - manual cleaning is necessary when mechanical facilities are not available or for cleaning delicate instruments or those which need to be taken apart to be cleaned. It is also used for narrow-necked jugs and bowls. Hand-cleaning must be done with extreme caution. The staff should wear heavy-duty rubber gloves, plastic apron, and eye protection. The instrument should first be soaked in hot water containing a foaming agent and detergent. The water is then drained carefully and the instruments separated. Care must be taken to ensure that the sharpends are away from the handler while handling instruments. the instruments are then washed gently; a soft brush should be used for delicate instruments and a high-pressure jet to clean the inside of hollow needles and tryphines. After washing, the instruments are replaced on a tray before autoclaving.
Equipment and Patient-Care Articles
General Use Articles
Fibre-optic endoscopes are usually heat-labile and therefore require chemical disinfection. 2% glutaraldehyde should be used under strict controlled conditions as required by the COSHH regulations. Protoscopes and sigmoidoscopes may be disposable or reusable. The latter must be cleaned, sterilized, or disinfected by heat or 2% glutaraldehyde.
ITUs, Operating Theatres