Optimising acoustic cavitation mediated decontamination of surgical instrumentation

Supervisor: Dr Paul Prentice, Cavitation Research Laboratory (CavLab)

Industrial Partner: Aseptium

There are over 4.7 million surgical procedures in the UK every year. Each surgery involves the use of a set of around 20 individual surgical instruments. Largely because of the cost associated with manufacturing surgical instruments, most of them are reusable – which means they need to be decontaminated between surgeries. Decontamination of surgical instruments demands physical removal of foreign matter from instruments followed by disinfection and sterilisation that inactivates whatever remains after the cleaning process to render instruments safe to use on patients. Cleaning is a critical step and if it is not done to a sufficient level the following disinfection and sterilisation are ineffective exposing patients to a direct risk of infections carried on dirty instruments.

Aseptium is a company that specialises in technologies for cleaning of complex surgical instruments. One of the core technologies used in Aseptium’s machines is ultrasonic cleaning. In this process Instruments are submerged in a liquid and energy is delivered to the surfaces of the instrument in the form of ultrasonic waves that create cavitation bubbles within the liquid volume. When these bubbles collapse shockwaves are generated that remove contamination from adjacent surfaces. Effectiveness of ultrasonic cleaning depends on the uniformity of bubble formation within the entire volume of the cleaning tank, the energy released during bubble collapse as well as bubbles ability to penetrate into intricate details of the surgical instruments.

A proposed study would investigate Aseptium’s current ultrasonic cleaning system from several perspectives.

  1. Measuring ultrasonic activity within the volume and potentially providing feedback to the control system or ultrasonic generator.
  2. Create a three dimensional map of cavitation activity in the cleaning tank and identify potential lower activity area, their size and potential impact on cleaning ability.
  3. Analyse the nature of the bubble formation and shockwaves within the tank and their ability to remove contamination from instruments.
  4. Investigate penetration capability of ultrasonic bubbles into the difficult to clean elements (crevices, holes, joints, channels etc)

The project will be undertaken in collaboration with the Cavitation Research Laboratory, Medical and Industrial Ultrasonics, School of Engineering UoG. Research infrastructure includes state-of-the-art high speed cameras, for imaging rapid acoustic cavitation bubble dynamics, and characterising the interaction with instrumentation. Novel in-house developed acoustic detection devices will be adapted and ultilised for monitoring, quantification and mapping capabilities

The researcher, under Aseptium’s guidance, would gain thorough understanding on cleaning processes and its criticality to healthcare delivery, as well as the key variables for industrial ultrasonic cleaning systems, including through fundamental research into the subject. Aseptium will provide the ultrasonic system and tests to measure cleaning ability as well as all necessary working knowledge to perform the experiments.