Every-Load Monitoring in Low-Temperature Sterilization: A Solution to Device Complexity and Failure Risks

Sterile Processing Perspectives with Marjorie Wall, EDBA< MLOS, CRCST, CIS, CHL, CSSBB

Sterilization plays a critical role in ensuring the safety of surgical procedures and patient care. With the rapid advancement of medical technology, modern surgical instruments, such as flexible scopes, cameras, robotic instrumentation, and gastrointestinal (GI) scopes, have evolved into more complex devices. These instruments are larger and composed of varied materials and are more expensive, making proper sterilization an ever-increasing challenge.

The push to sterilize GI scopes, which were traditionally high-level disinfected, adds a layer of complexity, as these sensitive devices are now subjected to more rigorous processes.¹ Additionally, the industry is pushing to use low-temperature sterilization for 3D-printed devices.²

Low-temperature sterilization methods, like Sterrad and V-Pro, have become essential for handling these heat-sensitive instruments. However, as these devices grow in complexity and health care facilities face increasing pressure to turn them over quickly for multiple procedures in a single day, the risk of sterilization failures rises. Overloading sterilizers, insufficient biological indicator monitoring, and device shortages add to this growing concern.

In this article, we will explore the challenges of sterilizing modern surgical devices and the steps health care facilities must take to mitigate risks and ensure patient safety, emphasizing the crucial role of continuous staff training in maintaining effective sterilization protocols.

Advances in Surgical Device Technology

Modern surgical devices, such as cameras, flexible scopes, and other instruments, have evolved significantly in recent years. These tools have become more intricate, incorporating larger sizes and combining materials like metals and polymer composites.² While beneficial for surgical precision and patient outcomes, this evolution presents new challenges for sterilization processes in health care facilities. Devices that once could be sterilized relatively easily are now composed of heat-sensitive materials, including advanced polymers, which are more prone to damage in traditional sterilization methods, such as autoclaving.²

The increased complexity of these devices demands different sterilization processes. Low-temperature sterilization methods, such as those employed by ASP’s Sterrad and Steris’s V-Pro, ensure these heat-sensitive polymers remain intact.² However, these methods present challenges. The materials used in modern devices often require precise control over sterilization parameters.³ Without careful adherence to these factors, sterilization cycles may be ineffective, leaving the equipment vulnerable to contamination.^3,4

Furthermore, as surgical instruments' packaging becomes heavier with added metal components, it becomes increasingly difficult for low-temperature sterilizers to penetrate and effectively sterilize all surfaces of the instruments.³ This is particularly challenging for vaporized hydrogen peroxide (VHP) systems commonly used in low-temperature sterilization processes.³ Inadequate penetration of sterilizing agents through heavier packaging can lead to failed sterilization cycles, putting patients at risk.³

In addition to the technical challenges, modern surgical devices' increasing complexity and cost contribute to higher maintenance demands.^3,5 As these devices become increasingly expensive, health care facilities must invest more in ensuring proper sterilization and maintenance protocols. Because of the higher costs, hospitals may not have enough instruments to support all scheduled procedures, leading to pressure on the sterile processing team to turn over the items quickly. This increases the risk of process failure, necessitating more rigorous sterilization and monitoring processes to ensure patient safety.^3,5

Challenges in Low-Temperature Sterilization

ASP Sterrad and Steris V-Pro sterilization systems are widely used in health care settings to sterilize heat-sensitive devices, such as flexible endoscopes, cameras, robotic scopes, batteries, and other medical instruments that cannot tolerate the high temperatures of steam-based sterilization. These systems utilize vaporized hydrogen peroxide (VHP) as the primary sterilizing agent.³ In this sterilization methodology, hydrogen peroxide is vaporized and injected into the sterilization chamber, creating a plasma that generates free radicals capable of breaking down microorganisms.³ This method is ideal for devices composed of sensitive materials, such as specific polymers and composites, as it operates at lower temperatures and is less likely to damage these components.³

While low-temperature sterilization methods such as Sterrad and V-Pro are essential for handling delicate instruments, they are challenging methodologies. Common causes of sterilization failures include improper loading of the sterilizers, overloading the sterilization chambers, and inadequate vapor penetration due to the complexity and density of modern devices.^3,4

For instance, when devices are packed too tightly or heavily, they can obstruct the even distribution of the vaporized hydrogen peroxide, leading to insufficient sterilization.^3,4 This issue is particularly critical for instruments with lumens, as the vapor may not adequately penetrate narrow or hollow spaces, increasing the risk of contamination.^3,4

Facilities often face shortages of critical medical instruments, particularly complex and expensive devices like flexible scopes and cameras. Due to these shortages, many facilities are forced to turn these instruments around quickly for multiple procedures throughout the day. This rapid turnover puts tremendous pressure on sterilization departments to reprocess instruments efficiently and effectively.

However, the rush to meet surgical demands often increases the risk of mistakes, such as skipping critical steps in the sterilization process or failing to allow adequate time for sterilization cycles.^3,4 These challenges are exacerbated by the increasing complexity of surgical devices, which often require more precise sterilization protocols.^3,4

One of the primary risks in facilities that must sterilize devices quickly is the tendency to overload sterilizers.3 Overloading occurs when too many instruments or large, complex devices are packed into the sterilizer simultaneously.³ This can prevent the sterilizing agent from fully penetrating all surfaces of the instruments, leaving them improperly sterilized.³ Overloading is a particular concern with low-temperature sterilizers, which rely on the proper distribution of vaporized hydrogen peroxide to achieve complete sterilization.³ When sterilizers are overloaded, the vapor cannot reach all areas of the load, increasing the risk that instruments will not be sterile when used in subsequent procedures.³

Biological Indicator Monitoring and Sterilization Process Failures

Biological indicators (BIs) play a critical role in monitoring the efficacy of sterilization cycles by providing a direct measure of the sterilization process's ability to kill highly resistant microorganisms.^3.6 BIs contain specific bacterial spores that are highly resistant to sterilization methods.⁶ After a sterilization cycle, the BI is incubated, and if the spores do not grow, the cycle is considered successful.⁶ This process ensures that sterilization has effectively destroyed all viable microorganisms.⁶ BIs are considered the gold standard for verifying sterilization because they directly test the biological lethality of the process rather than relying solely on physical or chemical indicators.^3,6

Every-load biological monitoring is an increasingly recommended practice for ensuring the sterility of instruments after each sterilization cycle.⁶ Every-load biological monitoring has become a standard practice for steam sterilization, but its use in low-temperature sterilization, such as Sterrad or VPro systems, is less common.⁷

According to Gene Ricupito, CRCST, CIS, CHL, CFER, PMP, a key reason for this difference lies in the history of BI monitoring.⁷ When Sterrad was first introduced in 1994, no self-contained BI tests were available for the system, which contributed to the technology not being approved for processing implants.⁷ At that time, the driver for implementing every-load biological monitoring in steam and ethylene oxide (ETO) sterilization ensured no implant load was run without a BI test. However, this was not seen as a compelling reason to use every-load biological monitoring with VHP systems, as implant monitoring was not a requirement, and the technology did not support it.⁷

In 2003, the FDA approved ASP's CycleSure BI test for Sterrad, but with an initial 48-hour read time later reduced to 24 hours.⁷ However, the long readout times made every-load biological monitoring impractical compared to steam BI tests, which had achieved a 3-hour read time for steam Prevac cycles.⁷ With technological advances, steam and low-temperature BI readouts can be completed in under 30 minutes, with expectations that this could drop to below 10 minutes in the near future.⁷ As Ricupito explains, this technological shift and the growing use of 3D-printed patient-specific implants that cannot always be sterilized via steam may soon lead to FDA approval of VHP sterilization for processing certain types of implants.⁷ This development could drive broader adoption of every-load biological monitoring in low-temperature sterilization systems, providing facilities with the confidence that every sterilized load meets the requirements.⁷

While not all standards require load monitoring for every cycle, the risks associated with a failed load can be significant. "When evaluating the facility's financial and credibility impact, increasing the monitoring frequency can increase confidence while balancing the economic sustainability and risks of load failure.”⁸ Although every-load monitoring is not always mandated, facilities that do not implement this practice face higher risks of costly recalls and reputational damage if a positive BI is detected after the equipment has been used.

Facilities implementing every-load monitoring can quickly detect issues, such as a positive BI, before instruments are returned for use.⁶ However, in some cases, especially when facilities are processing loads rapidly, positive BIs may be missed, resulting in non-sterile instruments being inadvertently used in procedures.⁶ This practice becomes even more critical when devices are being turned over for multiple uses in a single day, increasing the likelihood of process errors.^3,6

As Kronstedt8 notes, "When considering the frequency of load monitoring, consider variables such as the age of equipment, frequency of past failures, load recall ability, water, and heating dependability. The more variables that can influence the risk of failure, the higher the testing frequency should be considered."

Ricupito argues that the value proposition for every-load biological monitoring is the same regardless of the sterilization method.⁷ It ensures that all possible measurements for sterility have been met for every item processed for patient use.⁷ As the technology for rapid BI readouts improves and the use of complex implants grows, the costs of implementing every-load biological monitoring become nominal compared to the benefits of establishing a uniform standard of care across all sterilization modalities.⁷ This sentiment aligns with the growing interest in expanding every-load biological monitoring to low-temperature sterilization methods to mitigate risks and ensure the highest patient safety standards.⁷

Facilities that do not implement every-load BI monitoring face significant risks, as instruments may be used on patients before confirming that the sterilization process was effective.^3,5 Kronstedt⁸ further explains, "If the load monitor does return failed, what are the costs of reprocessing the processed loads? Tracking down what was used when and on what patients?" This creates logistical challenges and introduces potential liability concerns, including health care-associated infections and loss of market confidence.⁵ The potential consequences, ranging from reputational damage to costly lawsuits, highlight the importance of every-load monitoring to protect patients and the institution.^5,7,8

Best Practices and Recommendations for Mitigating Risks

Proper loading is essential to ensure that sterilization cycles are efficient and effective, especially when dealing with heavier and more complex devices.⁴ When loading instruments into sterilizers, avoiding overpacking trays or placing items too closely together is essential, as this can obstruct the flow of sterilizing agents like vaporized hydrogen peroxide (VHP).⁴ Instruments should be spaced evenly to improve penetration, and devices with lumens or narrow spaces should be positioned to allow maximum exposure to the sterilizing agent.⁴ Additionally, ensuring that heavier instruments are not concentrated in one area but distributed across the load can help maintain consistent vapor penetration, which is crucial for thoroughly sterilizing complex devices.⁴

Every-load biological monitoring is invaluable, especially when dealing with expensive and intricate instruments that must be turned over quickly for multiple procedures in a single day.^5,6 By conducting biological monitoring for each sterilization load, facilities can promptly identify any potential issues and prevent using non-sterile instruments.5,6 This approach ensures that even with quick turnovers, the integrity of the sterilization process is maintained, minimizing the risks associated with contamination and infection.^5,6 For facilities managing complex devices like cameras and flexible scopes, every-load monitoring provides the reassurance needed to avoid costly and dangerous sterilization failures.^5,6

Every-load biological monitoring helps facilities detect failures and protects them from the financial and reputational risks that come with missed sterilization errors. As Kronstedt⁸ points out, increasing the frequency of monitoring "can increase confidence while balancing the economic sustainability and risks of load failure." When dealing with expensive and intricate instruments, every-load monitoring ensures that even with quick turnovers, the integrity of the sterilization process is maintained, minimizing the risks of contamination and infection.^5.6

Conclusion

As surgical instruments become more complex, the need for advanced sterilization methods, such as low-temperature sterilization, has become critical in ensuring patient safety. The evolving nature of medical devices, larger, more intricate, and made from sensitive materials, requires sterilization protocols that can adapt to these changes. Facilities must prioritize every-load biological monitoring to detect potential failures before instruments are used, particularly in environments where rapid turnover is required. By embracing these practices, health care facilities can minimize the risks posed by complex devices and ensure the highest standards of patient care.

References:

1. Advanced Sterilization Products Announces FDA Clearance for Revolutionary Sterilization Cycle for Duodenoscopes in Partnership with PENTAX Medical. Business Wire. August 5, 2024. Accessed September 26, 2024. https://finance.yahoo.com/news/advanced-sterilization-products-announces-fda-122900982.html
2. Wiseman J, Rawther T, Langbart M, et al. Sterilization of bedside 3D-printed devices for use in the operating room. Ann 3D Print Med. March 2022;5. doi:10.1016/j.stlm.2022.100045
3. Seavey R. Troubleshooting failed sterilization loads: Process failures and wet packs. Am J Infect Control. 2016;44:29-34. doi:10.1016/j.ajic.2016.03.001
4. Basu D, Bag SC, Mukherjee S, Goel G. Advantages and limitations of rapid biological indicator for fast sterilization assurance. J Acad Clin Microbiol. 2020;22(2):66-60.
5. Veale J. Routine monitoring is critical to patient care. Biomed Instrum Technol. 2022.
6. Antonelli SS, Zeck J. Driving to zero: The rationale for every load monitoring across sterilization modalities. 3M Healthcare Academy. Accessed September 26, 2024. https://education.healthtrustpg.com/calendar/driving-to-zero-the-rationale-for-every-load-monitoring-across-sterilization-modalities/
7. Ricupito G. Interview by Wall M. Sr. Project Manager, Sterile Processing, UCSF. September 9, 2024.
8. Kronstedt L. Interview by Wall M. President of the Wisconsin HSPA Chapter, Co-Chair of the HSPA Chapter Representative Committee. September 22, 2024.