Type of Surface Change
Colored deposits consisting of:
- drug residues
Origin & Causes
in manual processing and ultrasonic cleaning:
- Long interval between use and processing (i.e. preparation for reuse),
- use of unsuitable instrument disinfectants,
- use of contaminated cleaning and disinfecting agents,
- insufficient rinsing after treatment,
- presence of sound shadows (ultrasonic cleaning).
in mechanical (machine-based) processing:
- Water feed temperature too high (exceeding 45°C) in first rinsing phase,
- ineffective rinsing (insufficient water flow through or around the instruments, insufficient rinsing pressure, rinsing shadows), poor maintenance of cleaning/disinfecting apparatus, etc,
- foam formation due to cleaning or disinfectant residues carried over from the ultrasound or immersion bath,
- improper charging/loading due to use of wrong instrument trolley/trays, overloading, leaving instruments fully assembled, processing jointed instruments in closed condition.
- Recleaning with ultrasound
- Targeted manual recleaning
- Remove coarse contamination immediately (see RKI recommendation in "Anforderung an die Hygiene bei der Aufbereitung von Medizinprodukten" [Hygiene requirements for the (sterile) processing of medical devices], item 2.2.1).
- Shorten the interval between instrument use and processing for reuse (< 6 hours).
- Use detergent-disinfectants for wet disposal.
- Feed water temperature in machine processing: max. 45°C.
Can lead to corrosion also in stainless steels because blood, for example, contains chloride ions. If present in higher concentrations, these ions cause pitting and/or possibly stress-crack corrosion.