EFHSS Questions and Answers - Question Q00323

We are an infection ontrol group in a private braziliam hospital. We are considering use of formaldehyde autoclave for heat sensitive items, but experience is very limited in our country. Could you please send comments from European experience oncerning efficacy and monitoring?

Thank you

M. Beatriz Souza Dias, MD
Hospital Sírio Libanes
São Paulo, SP
Brazil

Hello Beatriz

The efficacy depends mainly on a condensate film forming on all surfaces of the device. LTSF sterilising can inactivate most micro-organisms, but not Prion agents, where it is contra-indicated. It is applicable for some heat-sensitive, electronic devices and older endoscopes that cannot be steam sterilised. Restrict use if possible, by using thermal disinfection for semi-critical devices. Items must be free from organic material as formaldehyde fixes proteins.

Workers health - Health risks are associated with exposure to gas and liquid. Special training is required to avoid or minimise exposure as formaldehyde is an irritant, allergen and possibly a carcinogen. Acute reactions occur when mucous membranes are exposed. Risks and reactions are relative to product concentration levels. Have a seperate, well ventilated room for the steriliser. Protect eyes and skin from exposure, avoid inhalation. Monitor worker exposure levels, dosimeters available.

Programmes - temperatures can be 50 °C, 60 °C or 73-80 °C, in Scandinavia 78 °C is prefered. Process monitoring is done by physical control of cycle phases and parameters. Most modern sterilisers have built-in safety mechanisms that will abort faulty cycles. Gas concentrations cannot be measured during routine use, therefore we use chemical and biological indicators to ensure satisfactory gas exposure. Chemical indicator on each product to be sterilised, biological indicators with each load are recommended.

Packaging - use a minimum of packaging material, plastic/paper bags or pouches are good, place plastic side to plastic.Have good space between packs to ensure optimal gas penetration. Place items standing not lying flat, if possible, to ensure condensate drains away quickly. Look for white paraformaldehyde deposits on devices, materials and chamber walls, seek help if occurs.

Loading - Do not overload, observe manufactures recommended weight per load or basket.

Hope this helps,
Linda Ashurst
Rikshospitalet
Norway

Dear,

See also the answer on question Q00232.

Good luck,
Wim Renders