Effects of Time, Temperature, and Humidity on Soil Drying on Medical Devices

Influence of drying time on the removal of blood from medical devices

BACKGROUND

When processing surgical instruments after use, the safe, residue-free removal of blood and blood-containing soiling is one of the most important tasks. There are recommendations from various working groups regarding the ideal timeframe for cleaning used instruments in order to ensure safe disinfection and sterilization and avoid adverse effects. These are generally based primarily on practical experience and there is little systematic work on this topic.

AIM

In the present study, cleaning experiments with test specimens previously contaminated with sheep's blood were performed, and in this way the effects of the drying time of whole blood on the results of the subsequent cleaning were examined.

METHODS

Reflecting practice, both visual and spectroscopic methods were used to quantify residual protein. The experimental results were evaluated both as a function of the drying time and the residual moisture of the blood.

FINDINGS

Drying blood was particularly difficult to remove within the first 1-2 h. In this phase, in which the blood is coagulated but not yet completely dried, considerably more protein residues remained on the test specimens after cleaning than after longer standing times.

CONCLUSION

There is a timeframe for the removal of blood residues in which optimum cleaning results can be expected. As a consequence, there are also standing times that are disadvantageous for reprocessing. Based on the experimental data, it was deduced that this optimum time is either directly after contamination or in the range of >3 h and <24 h after soiling.

Digital technologies to unlock safe and sustainable opportunities for medical device and healthcare sectors with a focus on the combined use of digital twin and extended reality applications: A review

Medical devices have increased in complexity where there is a pressing need to consider design thinking and specialist training for manufacturers, healthcare and sterilization providers, and regulators. Appropriately addressing this consideration will positively inform end-to-end supply chain and logistics, production, processing, sterilization, safety, regulation, education, sustainability and circularity. There are significant opportunities to innovate and to develop appropriate digital tools to help unlock efficiencies in these important areas. This constitutes the first paper to create an awareness of and to define different digital technologies for informing and enabling medical device production from a holistic end-to-end life cycle perspective. It describes the added-value of using digital innovations to meet emerging opportunities for many disposable and reusable medical devices. It addresses the value of accessing and using integrated multi-actor HUBs that combine academia, industry, healthcare, regulators and society to help meet these opportunities. Such as cost-effective access to specialist pilot facilities and expertise that converges digital innovation, material science, biocompatibility, sterility assurance, business model and sustainability. It highlights the marked gap in academic R&D activities (PRISMA review of best publications conducted between January 2010 and January 2024) and the actual list of U.S. FDA's approved and marketed artificial intelligence/machine learning (AI/ML), and augmented reality/virtual reality (AR/VR) enabled-medical devices for different healthcare applications. Bespoke examples of benefits underlying future use of digital tools includes potential implementation of machine learning for supporting and enabling parametric release of sterilized products through efficient monitoring of critical process data (complying with ISO 11135:2014) that would benefit stakeholders. This paper also focuses on the transformative potential of combining digital twin with extended reality innovations to inform efficiencies in medical device design thinking, supply chain and training to inform patient safety, circularity and sustainability.

Validation of the Device Feature Approach for Reusable Medical Device Cleaning Evaluations

The identification of worst-case device (or device set) features has been a well-established validation approach in many areas (e.g., terminal sterilization) for determining process effectiveness and requirements, including for reusable medical devices. A device feature approach for cleaning validations has many advantages, representing a more conservative approach compared with the alternative compendial method of testing the entirety of the device. By focusing on the device feature(s), the most challenging validation variables can be isolated to and studied at the most difficult-to-clean feature(s). The device feature approach can be used to develop a design feature database that can be used to design and validate device cleanliness. It can also be used to commensurately develop a quantitative cleaning classification system that will augment and innovate the effectiveness of the Spaulding classification for microbial risk reduction. The current study investigated this validation approach to verify the efficacy of device cleaning procedures and mitigate patient risk. This feature categorization approach will help to close the existing patient safety gap at the important interface between device manufacturers and healthcare facilities for the effective and reliable processing of reusable medical devices. A total of 56,000 flushes of the device features were conducted, highlighting the rigor associated with the validation. Generating information from design features as a critical control point for cleaning and microbiological quality will inform future digital transformation of the medical device industry and healthcare delivery, including automation.

Test Soil and Material Affinity for Reusable Device Cleaning Validations

While selecting the test variables for a cleaning validation for reusable medical devices, the manufacturer must provide a simulative and clinically representative challenge for the device. An appropriate challenge must be identified with care so as not to overchallenge the cleaning process by selecting the worst case for every variable, thus leading to an impossible validation or unrealistic processing requirements. To appropriately select the testing variables, an understanding of the challenge to the cleaning process is important. The relationship among device material, test soil, and application method was investigated by testing 140 variable combinations, including seven materials (stainless steel, polyoxymethylene, polyether ether ketone, nitinol, aluminum, titanium, and silicone), four test soils (defibrinated blood soil, coagulated blood, modified coagulated blood, and Miles soil), and five soil application methods (pipetting neat, pipetting spreader, painting, handling with soiled gloves, and immersion). Stainless steel was the only material that showed consistent soil application in a thickness (at ~6 μL/cm2) that fully covered the test surface without some element of pooling, cracking, flaking, or soil migration with all test soils and application methods. The data collected using solubility testing indicated that a complex relationship for material adherence may exist between device materials and test soil. Stainless steel was the most challenging material tested.