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Disinfection Policy

 

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.    

Waste disposal

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.

Processing instruments

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;-

  1. Washing machine - this gives a cold rinse, followed by a hot wash at 71oC for 2 minutes, and a 10-second hot water-rinse at 80-90oC before drying.
  2. Washer/disinfector - this is mainly used for anaesthetic equipment. It runs a 45-minute cycle of washing and cleaning plus a 2-minute cycle with water at 80-100oC and a detergent.
  3. Ultrasonicator - this uses high-power output to dislodge all organic matter.   

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.    

Sterilization

  1. Autoclave (moist heat) - this is by far the most commonly used process and the most reliable. Moist heat penetrate and kill bacteria at temperatures lower than that required by dry heat. Steam penetrates best when air has been removed and the air is removed by (1) mechanical means, (2) downward displacement, and (3) pulse prevacuum, the latter of which is now the most commonly used method. The moisture content of the steam is very important, the optimum conditions for steam sterilization occurs when the steam is saturated (relative humidity = 100%). The packs of equipment should come out of the autoclave dry, if not, then the packs cannot be considered as non-sterile.
  2. Dry heat - dry heat sterilization is used for non-aqueous fluids, delicate instruments, hollow needles, glass, metal and waxes. It is unsuitable for rubber, plastics, combustible substances, and glycerol. Items to be sterilized should be wrapped in craft paper and aluminum foil. The oven is then heated to 160-180oC for a set period of time and then allowed to cool. The disadvantages of dry heat sterilization are (1) the sterilization cycle is long, (2) uneven heat distribution in the oven results in a marked temperature variation.
  3. Ethylene oxide - ethylene oxide can be used to sterilize most articles that can withstand temperatures of 50-60oC. However it must be used with extreme caution as it is extremely toxic and explosive. A long period of aeration is required to remove all traces of ethylene oxide
  4. Low pressure steam formaldehyde - as in the case of ethylene oxide, it is a very versatile method of sterilization.
  5. Radiation - this is only used industrially  
  6. Glutaraldehyde (2%) - this is used for disinfecting endoscopes, bronchoscopes, and other fibre-optic instruments. The COSHH regulations require its use to be controlled and the equipment rendered safe. Protective clothing must be worn which include gloves, eye goggles, masks, and impervious body covering. Either a well-ventilated room (with exhaust to the outside), a fume cabinet, or a closed system such as a fibre optic disinfection trolley must be used. The environment used should be tested from time to time by gas or HPL chromatography for the presence of aldehydes every 14 months.

 

Equipment and Patient-Care Articles

 

General Use Articles

  1. Bedpans and Urinals - gloves should be worn to empty the bedpan and its contents directly into the bedpan disinfector. Alternatively, the contents may be flushed down the sluice or toilet and then washed thoroughly with warm water and detergent to remove all signs of organic contamination and dried. The bedpan disinfector is the preferred method and it functions at no less than 80oC for 1 minute.
  2. Washing bowls - these must be washed thoroughly between each patient and stored and inverted to dry. Fresh water and towels should be used for each patient.
  3. Towels, soaps, hairbrushes, shaving brushes etc. - all these items should be for individual use only and should never be shared.
  4. Crockery and cutlery - each patient should have an individual set. the crockery and cutlery should be washed in very hot water (>60oC) and detergent. Disposable crockery is only necessary in cases of strict isolation such as rabies.
  5. Mattresses and pillows - they are a major source of cross-infection. Wet mattresses must be changed. Contaminated mattresses should be washed with warm water and detergent. Mattresses should be covered with an impervious layer so that they can be cleaned thoroughly between patients. Damaged mattresses should be discarded as they may easily trap microorganisms.
  6. Thermometers - they should be washed in warm water and dried before being wiped over with a swab soaked in 70% isopropyl alcohol. They should never be soaked in disinfectants.
  7. Trolley tops - they should be washed with warm water and detergent  

Endoscopy Unit

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

  1. Ventilatory circuits - multiple-use circuits must be heat-disinfected for at least 80oC for 3 minutes or sterilized by autoclave or ethylene oxide between each patient. Filters may be used between circuits and if properly maintained, a ventilated patient may use the same circuit for 4-5 days before disinfection.
  2. Humidifiers - humidifiers are a common source of viruses and Gram-negative bacilli and should be emptied daily and refilled with distilled water. They should be disinfected when contaminated or when the respiratory circuit is changed. Routine heat disinfection is essential after each patient use and if humidification is required for a prolonged period, the humidifier should be cleaned thoroughly, dried, and filled daily with distilled water.
  3. Endotracheal suction catheters - they are usually disposable but may be used up to 24 hours on the same patient.
  4. Endotracheal tubes - these may be recycled after thorough cleaning and autoclaving. Disposable endotracheal tubes are available but are more expensive.
  5. Ambu-bags - they are extremely difficult to disinfect and become contaminated very quickly. Heat is the most reliable method and 2% glutaraldehyde is a less acceptable alternative.
  6. Oxygen-delivery face masks - these can be disposable or reusable. If reused, they should be washed thoroughly and wiped over with 70% isopropyl alcohol.
  7. Suction and drainage bottles - these are usually disposable, with a self-dealing inner container held in a clear outer plastic container. The outer container should be heat-disinfected or autoclaved after each use. Non-disposable bottles must be changed every 24 hours or sooner if full. They must then be washed and autoclaved. Recyclable connector tubing should be cleaned thoroughly and sterilized. The system must be closed and risk to staff from body fluids should be minimal.
  8. Incubators in SCBU - they should be cleaned thoroughly with warm soapy water and then wiped over with 70% isopropyl alcohol.  

Disposable Equipment

  1. Syringes and needles - disposable syringes and needles should be used. Under no circumstances should fine-bore needles be recycled because they cannot be cleaned. If syringes are to be recycled, it must be well controlled. After thorough cleaning, the syringes must be autoclaved or processed in ethylene oxide.
  2. Administration sets - administration sets for IV fluids must be disposable
  3. Urinary catheters and drainage bags - these should be single-use and disposable

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