Monitoring of cleaning processes

According to the requirements of the European Medical Devices Directive 93/42 (MDD) the cleaning of medical devices has to be validated. Validation means that the process

• 1. has to be effective and
• 2. must not change unnoticed later on during daily use, that means, it has to work reproducibly.

Therefore in automatic cleaning processes all parameters must be monitored to secure the reproducibility in washer/disinfectors (WDs). The parameters must not change unnoticed. Some process information is already provided by the WD itself using its integrated temperature and time gradient recording system. Some WDs also measure the dosage amount of the detergent and/or the rotation speed of the spray arms.

The following critical parameters cannot be monitored by WDs themselves:

• 1. Changes of the water quality, e.g. of water hardness, salt content, etc.
• 2. Wrong selection of the detergent (mix-up of canisters)
• 3. Use of an expired detergent with less cleaning efficacy
• 4. Selection of a wrong program (for the load)

To be able to monitor these parameters not monitored by the WD, gke has developed artificial test soils on cleaning indicators to be placed in the process and visually check their wash-off extent after the cleaning process.

The indicators are offered in different wash-off difficulty levels, so that for each individual cleaning process the suitable indicator can be selected. The recommendation for monitoring of medical devices of the Robert Koch Institute (RKI) mentions cleaning indicators. Generally cleaned instruments have to be optically checked for visible remaining soils on their surfaces. If complex e.g. critical B instruments have been cleaned, the optical check may not be possible because inner surfaces