Cleaning Indicators with hollow flow PCD and holder


The gke Clean-Record®cleaning test system is used for validation and routine monitoring of cleaning processes. The indicators can be used in washer disinfectors (WD) as well as cleaning of bedpans (Level 0 indicator) and also in ultra sonic baths for the manual cleaning for all kinds of instruments. To test hollow instruments, a special hollow flow process challenge device (PCD) can be connected to the hose connection of minimal invasive surgical (MIS) instrument and endoscope carts.
Surgical instruments are contaminated with various soils. Depending on the pre-treatment of instruments the adhesion may be different. Body fluids consist 75-85% of water soluble proteins and can be washed off with cold water. Instruments should be cleaned with cold water directly after use before the soils can adhere and before disinfectants are used which are fixing soils.The use of cleaning detergents is very important for the efficacy of cleaning processes if non watersoluble soils are contaminants. Only water-soluble soils can be washed off with water.

Fats and other non water soluble soils, e.g. lipids can only be washed off, if a cleaning detergent is used. Some cleaning detergents are alkaline and hydrolize the non water soluble substances by using a high pHvalue making them water soluble. Other cleaning agents have a neutral pH-value containing enzymes. Both mechanisms can be combined in one cleaning detergent. Cleaning detergents are optimized depending on the contaminations on the instruments. Therefore, the optimal cleaning agent has to be chosen accordingly. Instruments made of aluminium-magnesium corrode at high pH-values. The water quality (hardness, salt content) highly influences the effectiveness of cleaning detergents.

gke offers different cleaning indicators for washer disinfectors which represent different challenge levels as proof of the cleaning efficacy. It is recommended to test all indicators at the same time together with the most difficult instrument sets as a preliminary test. For this evaluation an introduction pack is available which contains Level 1 to Level 4 indicators and three holders. Alternatively an introduction pack with multi-level indicators which contain the three most difficult indicators in one indicator is also available (see order information).

The indicator which has just been washed off completely in the WD-program and is also more difficult to clean than the most critical soil should be used for routine monitoring later on. For validation the results of the cleaning performance need to be compared with the results of the indicators to prove the „worst-case“ scenario.Within the WD chamber there are completely different spray conditions caused by different reasons:

  • 1. Lower spray conditions can be found in the corners and at the centre of the spray arm axles.
  • 2. Loads create spray shadows.
  • 3. Instruments have areas that are difficult to reach, e.g. splits.
  • 4. Channels which have to be flushed have different flow through characteristics because of their dimensions.

These situations must be considered during testing by positioning the indicator holder and/or using a hollow flow PCD in the WD or bedpan washer. Testing shall be carried out in different locations and the most difficult location should be selected for routine monitoring.In addition gke offers 4 different test sheets to check ultra sonic baths. The indicators should be immerged in fluids vertically or horizontally to check the different intensity in mechanical force inside the volume of the liquid. It is recommended to use these indicators at least once a day in every program used to ensure that there are no changes of the process parameters. It is also recommended to monitor each batch where loads are difficult to clean.For bedpan washersgke has developed a special cleaning indicator to check the efficacy of those processes.

Product Description

1. Cleaning indicators for WDs

gke produces 5 different self-adhesive indicators using temperature stable plastic carriers. All indicator substances have different adhesion characteristics. Therefore they require different strong mechanical spray force and different detergents to be washed off. The three most difficult indicators are also available as Multi-Level-Indicators (MLC) for test purposes. Different PCDs creating spray shadows to protect the indicator are not required since different cleaning properties are provided already by the 5 different indicator levels without using a PCD. The indicators are put in a holder (art. no. 800-100 or 800-102) which can be fixed on a tray. To monitor the cleaning efficacy of hollow instruments the folded indicator may be placed in a gke Clean-Record® Hollow Flow PCD which is supplied with 3 adapters of 2, 3 and 4 mm internal split.Small splits at the same flow rate create a higher internal flow through speed and therefore better cleaning efficacy as larger splits will create lower flow through speed and create worse cleaning conditions. Therefore the limits for the processing of endoscopic cleaning can be fully evaluated using up to 15 test conditions.At the end of the process the indicators can be adhered for documentation.

2. Test sheets for ultrasonic cleaning baths

There are 4 different difficult to wash off indicators to prove ultrasonic cleaning baths of a size of 125 x 56 mm to monitor the cleaning efficiency inside the liquid volume. gke offers two different holders to fix the indicator inside the ultrasonic bath at different locations in the volume. This test method offers the possibility to check the cleaning efficacy over time in the same liquid.

3. Cleaning indicators for bedpan washers

Cleaning indicators for bedpans are designed to be washed off in water without detergents. However the water quality and temperature also influences the wash-off speed. The indicator is self-adhesive and can be adhered directly on the bedpans. This test enables the user to check the cleaning efficacy over a long period and provides control and documentation about the result.

Performance Characteristics

The technical specification EN ISO/TS 15883-5 describes 19 test soils with completely different cleaning properties without making any recommendation, as to which test soil to use. Currently none of the test soils are offered as a reference, because there is no test method defined to compare the soil properties. The gke research centre has developed a test equipment (spray rig test) to be able to compare real soils, test soils of the standard and the different gke CleanRecord®cleaning indicators. Comparative tests with a normative standard are not possible since currently no standard is available. Still gke has already carried out several tests under different cleaning conditions (flow rate, detergents, dosage, temperature etc.) in order to compare the cleaning characteristics of the abovementioned materials and gke indicators. For the first time it is possible to describe the properties of cleaning indicators. Test results are available on request. The indicator colour is non-toxic and is dissolved with most of the cleaning agents and flushed away with the
washing fluid.

Benefits of the gke Clean-Record®indicators:

  •  Use of synthetic test soils on plastic carrier instead of using natural test soils with blood prevent transfer of pathogenic germs and offers long-term stability and long expiry dates.
  •  Cost-effective due to the use of plastic carriers and printed test soils.
  •  Permanent economical batch monitoring is, for the first time, possible because of a cost-effective production of the indicators.
  •  The 5 indicator levels require different mechanical force to be washed off and therefore, the use of PCDs is not required.
  •  Easy documentation because of self-adhesive indicators.
  •  All parts of the holder and PCD are made of durable materials and are maintenance free. They can be used for an unlimited number of cycles.
  •  Easy to use.

Additional benefits of the cleaning indicators

For WDs

  •  The gke cleaning indicators provide constant cleaning characteristics in comparison to natural test soil which may change their cleaning properties during storage time.
  •  The indicators are validated against test soils according to EN ISO/TS 15883-5 with a special spray equipment designed by gke.

For ultrasonic baths

  •  Special test sheets to monitor ultrasonic baths.
  •  Test of mechanical cleaning conditions of ultrasonic baths with 4 different indicators.
  •  The cleaning efficacy can be tested in all 3 dimensions of the volume using special holders.
  •  The cleaning efficacy of the bath can be controlled over time.

For bedpan washers

  •  A special adopted indicator for this application is available.
  •  The adhesive property allows easy fixation.
  •  Documentation of results is possible.