Question and answer

Journal of Hospital Infection (1986) 7, 3 l&31

Question

1

and answer

Which strengths of hypochlorite solution should be used for disinfection when there is the possibility of contamination by HTLV-III: for blood spillages, for environmental cleaning, and for rendering safe bloodstained excreta, aspirates be deconand clinical laboratory waste ? How may surgical instruments taminated before reprocessing? Recommendations of concentrations of hypochlorite to be used for disinfection purposes often cause confusion because the units in which they are expressed are imprecise. Percentages should be avoided, and concentration should be expressed as ‘parts per million of available chlorine’ (Shanson, 1980). Commercial preparations of hypochlorite, such as ‘Domestos’ or ‘Chloros’, are usually supplied at 100,000 ppm available chlorine, and standard dilutions of 10,000 and 1000 ppm available chlorine can be prepared freshly as they are needed (Shanson, 1980). The Hospital Infection Society’s working party on the acquired immune deficiency syndrome (AIDS) recommends that unified ‘Inoculation Risk’ procedures should be applied for both HTLV-III-risk and hepatitis-B-risk (Working Party, 1986). Decontamination procedures combine safe and careful handling, washing and treatment by heat or by disinfectants, usually hypochlorite. General disinfection of the environment in ward and theatre, and of laboratory bench surfaces, can be achieved with hypochlorite 1000 ppm available chlorine. Blood spillages should be covered with hypochlorite 10,000 ppm available chlorine before they are mopped up with absorbent paper in a gloved hand. Bloodstained water in wash bowls may be made safe by the addition of an equal volume of hypochlorite 10,000 ppm available chlorine and standing for + h. Disposable containers may be used in suction equipment, and the container and aspirate afterwards disposed of by incineration. Alternatively, the aspirate in a non-disposable container may afterwards be made safe as described above. Overfilling of the suction bottle with aspirates should be avoided as secondary contamination of the pump or other parts of the apparatus is more difficult to deal with. Bloodstained excreta may be treated similarly, by $ h exposure to an equal volume of hypochlorite 10,000 ppm available chlorine, but may be dispersed in the general sewage system, without this treatment, by decontamination of the bedpan or urinal in a washer-disinfector that maintains the temperature of the article at 80°C for 1 min. Instruments should ideally be transported in a sealed box, wrapped in an outer cover such as a plastic bag, and labelled to indicate Inoculation 310

Question

and Answer

311

Risk-directly to a central sterile supply department (CSSD). There they should be carefully transferred to an automatic hot washer that achieves a hold temperature of 80°C for 1 min, for decontamination before further processing. If such an effective washer is not available in the CSSD, the soiled instruments may be autoclaved or, better, disinfected by low temperature steam at 73”C, before they are handled further (cleaned and resterilized); but both these processes lack a washing component that removes dried blood or other secretions. Alternatively, instruments may be decontaminated before dispatch from theatre, by soaking in a freshly-prepared solution of 2% activated glutaraldehyde for + h. Laboratory waste should be safely contained until it can be incinerated, or autoclaved before disposal. If ‘discard jars’ are required, hypochlorite 10,000 ppm available chlorine should be used.

Bristol Royal Infirmary Bristol BS2 8HW

D. C. E. Speller R. A. Simpson References Shanson,

D. C. (1980).

Questions

and answers.

(Hypochlorite

concentrations.)

Journal

Hospital Infection 1, 88-89. Working Party of the Hospital syndrome: recommendations.

Infection

Society

(1985).

Acquired

immune deficiency 6C, 67-80.

Journal of Hospital Infection, Supplement

of