In ultrasonic baths different energy fields are generated depending on
the position of the ultrasonic transducers
The specified level for filling the baths must absolutely be observed
as this affects the energy input. Moreover, ultrasonic shadowing occurs
depending on the quantity, shape and position of the sterile items
and permit a more or less beneficial effect. In principle, inserts
or mesh trays whose meshes are not too narrow should be chosen. These
must be placed on the positioning rollers of the unit and under no
circumstances directly on the floor of the bath. The mesh trays
should not be overfilled. Nor should silicone mats be used as they
impede the ultrasonic effect. The load should be chosen such that the
mesh trays can be placed directly without reloading into the
washer-disinfectors immediately after ultrasonic treatment. Jointed
instruments should be opened and complex instruments may need to be
dismantled, while observing the manufacturer's instructions.
To achieve an optimal cleaning result, these
LOADING INSTRUCTIONS must be strictly observed.
The effect of disinfectants, and also
the cleansing ultrasonic effect, depends on the extent of
contamination and is adversely affected by extensive contamination.
Therefore the baths should be regularly renewed. The
FREQUENCY of renewal depends on how often the bath is used and on
the degree of contamination. Baths with visible contamination should
be renewed possibly several times each day. Otherwise, daily renewal
Normal drinking water can be used for
the ultrasonic bath. But some manufacturers recommend the use of
softened water or demineralised water. It has been demonstrated in
practice that preference should be given to
Field distribution and intensities of the cavitation field at one level of a commercial ultrasonic bath, showing the thermistor sensor
(Rudolf Reichl, NMI Naturwissenschaftliches und Medizinisches Institut at Tübingen University)
Experience from the practical setting:
- Mesh trays with highly contaminated instruments should always be pre-cleaned in the ultrasonic bath as otherwise they will not be properly cleaned in the washer-disinfector.
- Once a week all trays with instruments are subject to pre-treatment in the ultrasonic bath.
- Instruments are preferably processed in a tunnel washer with integrated ultrasonic bath.
- Hardened protein residues and rust are removed by using in the ultrasonic bath a general cleaning agent containing phosphoric acid. This also reinforces the passive layer and curtails susceptibility to rust. But only hardened instruments may be treated thus.
- Biopsy forceps are in principle cleaned in the ultrasonic bath and then rinsed, dried, packed and sterilised.
- Gynaecological instruments, e.g. specula, are often not cleaned properly. They must generally undergo pre-treatment.
- Microinstruments that can only be cleaned manually are cleaned in the ultrasonic bath.
with kind permission of|
What must be borne in mind when loading ultrasonic baths?
THE LOADING INSTRUCTIONS must be observed.
THE FREQUENCY of renewal of the baths must be determined.
SOFTENED WATER should be given preference.
Experience from the practical setting