In healthcare and laboratory environments, sterilization is an essential and highly regulated process that ensures instruments are completely free from harmful bacteria, viruses, and other pathogens. This rigorous sterilization process of medical equipment is critical not only for preventing the spread of infections but also for safeguarding patient health, minimizing the risk of healthcare associated infections (HAIs or HCAIs), and ensuring the safety and reliability of every procedure conducted with medical devices. Proper sterilization plays a vital role in reducing infection rates, which can occur from improperly cleaned or disinfected instruments, thereby directly protecting patients from potential harm. 

Among the various sterilization methods available, today we will focus on two of the safest and most widely used techniques: steam sterilization through autoclaves and gas plasma sterilization with STERRADTM systems. Both methods are integral to modern infection prevention practices, yet they differ significantly in their processes, applications, and advantages 4.

What is and how does an autoclave work?

An autoclave is a device used for sterilizing equipment and materials by subjecting them to high-pressure steam at elevated temperatures. The autoclave was invented by Denis Papin, a French physician and physicist, in the late 17th century. Denis Papin first described the concept in 1679 when he created a device, he called a "steam digester" or "Papin's digester," which utilized steam pressure to cook food faster. This invention laid the groundwork for modern autoclaves5.

The basic principle of steam sterilization, as accomplished in an autoclave, is to expose each item to direct steam contact at the required temperature and pressure for the specified time. Thus, there are four parameters of steam sterilization: steam, pressure, temperature, and time. 
The ideal steam for sterilization is dry saturated steam and entrained water (dryness fraction ≥97%).
Pressure serves as a means to obtain the high temperatures necessary to quickly kill microorganisms. Specific temperatures must be obtained to ensure the microbicidal activity. 
The two common steam-sterilizing temperatures are 121°C (250°F) and 134°C (270°F). These temperatures (and other high temperatures) must be maintained for a minimal time to kill microorganisms. 
Recognized minimum exposure periods for sterilization of wrapped healthcare supplies are 30 minutes at 121°C (250°F) in a gravity displacement sterilizer or 4 minutes at 132°C (270°F) in a prevacuum sterilizer6.

What is and how does STERRADTM System work?

A STERRAD™ sterilizer is a type of low-temperature sterilization system that utilizes hydrogen peroxide gas plasma technology to sterilize medical and surgical instruments. 

autoclave sterrad

How do Autoclaves and STERRADTM Systems differ?

 

How do the two sterilization system relate to temperature?

  • Autoclave: since autoclaves utilize high temperatures for sterilization, they are most effective for materials that can withstand such heat, including stainless steel surgical instruments and certain heat-resistant plastics. However, instruments that are sensitive to either heat or moisture may be compromised or damaged when subjected to autoclave processes¹.
  • STERRAD™ systems: STERRAD™ systems are specifically engineered to handle temperature-sensitive and moisture-sensitive instruments. Operating at lower temperatures, typically between 50–55°C (122–131°F), these systems are especially effective for delicate medical devices, including endoscopes with a maximum lumen length of 1,065 mm (check sterilizer IFU). The low-temperature approach ensures that instruments with complex electronic components or narrow lumens are protected from damage that might occur with traditional high-temperature sterilization methods, while still delivering thorough and effective sterilization².

 

What are the cycle times of autoclaves and STERRADTM Systems?

  • Autoclave: the duration of autoclave cycles can vary significantly based on factors such as load size and the type of materials being sterilized. Typically, these cycles can range from 15 to 90 minutes¹, accommodating various sterilization needs.
  • STERRAD™ Sterilizers: in contrast, STERRAD™ systems are known for their efficiency with shorter cycle times, generally between 28 to 75 minutes². This faster turnaround is particularly advantageous in emergency situations or high-volume environments where rapid instrument turnover is crucial for maintaining workflow and patient care².

 

How do autoclaves and STERRADTM Systems sterilization impact the environment?

  • Autoclave: autoclaves demand substantial amounts of water and energy to generate the steam necessary for sterilization. While they do not release harmful chemicals into the environment, the significant energy consumption involved in the process can pose challenges for facilities that are striving to adopt more sustainable practices³
  • STERRADTM system: the STERRADTM system is considered more environmentally friendly. It uses hydrogen peroxide, which breaks down into water and oxygen, leaving no toxic residues². Additionally, the low temperature and dry process require less energy than steam-based systems⁴.

 

What are the application fields of the two sterilization methods?

  • Autoclave: autoclaves are versatile and can sterilize a wide range of materials, including glassware, surgical instruments, and textiles¹. While highly effective, autoclaves are not suitable for all instruments, particularly those sensitive to heat and moisture. Additionally, their larger size and reliance on water and power can make them less practical for small facilities¹.
  • STERRADTM Sterilizer: is best suited for delicate, complex instruments, such as endoscopes, cameras, and instruments with narrow lumens². It’s commonly used in hospitals for devices that can’t withstand the high heat of autoclaves².

 

Conclusion

While both autoclaves and STERRAD™ systems are essential for maintaining sterile environments in healthcare and for ensuring patients safety, STERRAD™ sterilizer stands out with significant advantages. 
Autoclaves are suitable for heat-resistant instruments and are recognized for their reliability and versatility¹. However, STERRAD™ offers an innovative technology, using a low-temperature, rapid sterilization process that is not only ideal for delicate, heat-sensitive instruments but also far more environmentally friendly. By eliminating the need for excessive water and energy, STERRAD™ aligns with sustainability goals, making it the preferred option for facilities that prioritize both efficiency environmental responsibility and on top of everything, patients’ safety. ²

References

  1. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Centers for Disease and Control Prevention

  2. Advanced Sterilization Products: STERRAD Sterilization System Overview https://www.asp.com/our-products/sterrad/

  3. Steam sterilisation’s energy and water footprint. Forbes McGain, Jim Black https://www.fda.gov/medical-devices/reprocessing-reusable-medical-devices/

  4. Guideline for Disinfection and Sterilization in Healthcare Facilities (2008) - Steam Sterilization

  5. https://www.britannica.com/technology/autoclave

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