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Sterilisation of medical equipment in general practice

Julie Smith
SRN ONC
Specialist Nurse
General Practice Nursing
Chaddlewood Surgery
Devon

Infection control is extremely important in general practice due to the increase in minor surgery, the threat of viral infections such as hepatitis B, hepatitis C, HIV and human papillomavirus, and the rise in antibiotic-resistant microorganisms such as methicillin-resistant Staphylococcus aureus (MRSA).

High standards of cleanliness and hygiene are important for minimising the risk of infection. Decontamination is a combination of processes, including cleaning, ­
dis­infection and/or sterilisation:(2)

  • Cleaning: "Removal of accumulated deposits by washing with a cleaning solution and with ­thorough drying, to give a preliminary reduction in numbers of organisms and remove dirt, grease and organic matter which might protect organisms from heat or chemical disinfection."
  • Disinfection: "The removal of pathogenic organisms, not including spores, therefore reducing the total number of organisms present. Cleaning and disinfection aims to reduce the number of organisms to below that required to cause infection."
  • Sterilisation: "Complete removal of all organisms including spores - this concept is absolute, ie, an item is either sterile or nonsterile."

Table 1 lists the choice of decontamination methods for all reusable medical devices.(2) The first step is manual cleaning, to physically remove microorganisms. Cleaning is a necessary prerequisite of equipment ­decontamination to ensure effective disinfection/sterilisation. A designated sink is required for the purpose, plus a separate sink for handwashing.(2) The suggested protocol is as follows:

  • Protective clothing should be worn at all times.
  • Dirty instruments are initially placed in cold water and brushed to dislodge any visible soil. When this process is completed instruments are removed and the water drained before the next stage.
  • A dedicated sink is filled with hot water and a ­general-purpose detergent (accurately diluted in accordance with the manufacturer's instructions).
  • A supply of cleaning implements and accessories (brushes/cloths) must be available. Brushes and cloths must be kept dry.
  • Fully immerse the instruments in the solution and keep under the water during the cleaning process to prevent spray.
  • Brush, wipe, irrigate or hand spray the item to ­dislodge all visible debris.
  • Remove instruments from the sink and fill the sink with water.
  • Fully immerse the instruments to ensure any excess detergent has been removed.
  • Remove the items and dry thoroughly.
  • Separate dirty and clean surfaces to reduce ­contamination before and after decontamination is complete.

[[NIP08_table1_44]]

Due to the lack of control methods available to test the efficiency of manual cleaning, a swab and check may be used as a quality control test. This entails swabbing an item that has been risk assessed, manually washed and appropriately disinfected and/or sterilised. This swab is analysed at a hospital-based microbiology ­laboratory to ascertain if the item is cleaned to its safe level.

Sterilisation
The sterilisation process is possibly the most difficult. Here are some key points that are achievable:(3)

  • Autoclaving is the recommended method of ­sterilisation, and a sterile supplies department (SSD) that meets regulatory requirements is the best way to achieve this.
  • If this is not possible, buy a transportable steam steriliser that the ­supplier confirms is suitable for processing the intended loads.(4) Training on use and maintenance must be provided.
  • Use only sterile distilled or deionised water in sterilisers; the reservoir should not be topped up, and should be left dry at the end of the working day.
  • Instruments should be sterilised at three minutes at 134-7°C; or 10 minutes at 126-9°C; or 15 ­minutes at 121-4°C.
  • When loading instruments into the steriliser ensure that they are dry and not touching. Leave hinged instruments open.
  • Instruments must be unwrapped and not in ­pouches unless a vacuum steam steriliser is used.(5)
  • For invasive procedures use instruments immediately after being sterilised. For noninvasive procedures store instruments in a clean, dry, dust-free place.
  • Do not soak instruments in disinfectants before or after sterilising.
  • Instruments with narrow lumens or wrapped instruments must not be sterilised in benchtop steam sterilisers, as they will not be adequately clean.
  • Retain records of maintenance checks for at least 11 years for accountability.

It may be useful to invite the local manager of the SSD to meet with staff at your practice to discuss the options. This is especially important with regards to clinical governance - as nurses we are accountable for our actions, and if we cannot safely undertake procedures, backed by evidence- based practice, we should be saying NO!(6)

References

  1. Hoffman P. Med Horizons 1989;Oct:17-9.
  2. Cumbria and Lancashire Health Protection Unit. Guidance for the sterilisation and decontamination of medical devices in the community setting October 2001. Available from URL: http://www.healthprotection.org.uk/policies/decontamination policy.pdf
  3. MDA. Sterilisation, disinfection and ­cleaning of medical equipment: parts 1, 2 & 3. London: MDA; 1996.
  4. MDA. The purchase, operation and ­maintenance of bench top steam sterilisers (MDA DB 9605). London: MDA; 1997.
  5. MDA. The validation and periodic testing of bench top vacuum team sterilisers (MDA DB 9804). London: MDA; 1998.
  6. RCN. Good practice in infection control: guidance for nurses working in general practice. London: RCN; 2000.

Resources
MDA Bulletins are ­available free of charge from:
Department of Health
PO Box 410
Wetherby
LS23 7EL
F:01937 845 381
(Quote title and reference number)
For other MDA ­publications contact:
DTS Business Services
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Hannibal House
London SE1 6TQ
F:020 7972 8124
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