The Top 8 Hospital Sterilization Cycles for CSSDs & SPDs

Central sterile supply departments (CSSDs) and sterile processing departments (SPDs) play an integral role in hospitals and ambulatory surgery centers (ASCs), ensuring surgical instruments, medical devices, and other essential equipment are sterilized and ready for use. From cleaning and decontamination to storage and distribution, CSSDs and SPDs maintain rigorous processes to maintain the highest standards of patient care and infection control, helping prevent the spread of healthcare-associated infections (HAIs).

No CSSD or SPD would be complete without an autoclave. This powerful piece of equipment is indispensable to hospitals and ASCs, providing a reliable, repeatable, and highly efficient way to sterilize supplies, upholding the safety and integrity of medical procedures. In this article, we’ll discuss how the right autoclave can help CSSDs and SPDs overcome common hospital sterilization challenges, and show you how to choose the right sterilization cycle for different types of medical equipment.

Steam Sterilization in CSSDs & SPDs

Regarded as the most dependable form of sterilization,¹ steam sterilization is known for its ability to thoroughly penetrate and kill all forms of microbial life on glassware, textiles, steel instruments, liquid media, and autoclave-safe plastics. The sterilization process involves exposing items to high-pressure saturated steam at high temperatures, typically between 100°C (212°F) and 135°C (275°F), for a set period of time.

In addition to its efficacy and reliability, steam sterilization is the preferred sterilization method for most CSSDs and SPDs due to its efficiency. Compared to other sterilization methods such as ethylene oxide or vaporized hydrogen peroxide, steam sterilization cycles are relatively short, ranging from a few minutes to just over an hour depending on the load.

Certain autoclaves even offer immediate-use steam sterilization cycles (IUSS), which are performed at elevated temperatures and can run anywhere from three to five minutes for unwrapped goods to six to 10 minutes for wrapped goods. IUSS cycles are especially popular in hospitals, ASCs, and other healthcare facilities, which typically need to sterilize large volumes of equipment, sometimes for emergency use, in a brief window of time.

Unlike other sterilization methods, steam sterilization leaves no chemical residuals on the load, increasing both technician and patient safety. Additionally, some autoclaves feature built-in water- and energy-saving capabilities that reduce medical facilities’ resource consumption, which can lower operating costs while promoting sustainability.

Common Sterilization Challenges CSSDs & SPDs Face

Central sterile supply departments and sterile processing departments serve a vital function in any healthcare facility, ensuring medical professionals have access to the instruments and equipment they need, when they need it — but doing so is often easier said than done. Here are some common challenges CSSDs and SPDs face when sterilizing equipment:

• Diverse Instrumentation: From surgical instruments and implantable devices to lab equipment and bed linens, hospitals and ASCs use a wide variety of materials, many of which have unique sterilization requirements. For example, metal surgical instruments such as scalpels, forceps, and clamps are able to withstand high temperatures, making them relatively easy to autoclave. However, endoscopes and other polymer-based instruments and medical devices require specialized sterilization technology so as not to damage the device and/or release any byproducts.
• Rapid Turnaround Times: CSSDs and SPDs are under immense pressure to sterilize large volumes of essential equipment in accordance with stringent infection control standards and regulations while still delivering rapid turnaround times. Any delays in processing could delay procedures — a frustrating turn of events for medical professionals and patients alike. To reduce turnaround times, hospitals and ASCs must invest in autoclaves capable of sterilizing large volumes of equipment in short order, as well as autoclaves with IUSS cycles for emergency situations.
• Compliance & Documentation: CSSDs and SPDs must maintain detailed documentation of all sterilization cycles² to demonstrate adherence to regulatory standards. This documentation is important not only for compliance purposes, but also quality assurance and patience and patient safety, as it ensures that the CSSD or SPD followed all of the necessary steps in the sterilization process.
• Spatial Constraints: Space is often limited within CSSDs and SPDs, and these limitations can restrict the amount and size of sterilization equipment used, while layout inefficiencies can create process bottlenecks. Redesigning or otherwise modifying these spaces to accommodate medical-grade sterilization equipment capable of meeting a healthcare facility’s needs is often not an option, so it’s important that hospitals and ASCs select autoclaving units that can be customized to fit their space.
• Resource Utilization: As noted, steam sterilization is more effective and efficient than other forms of sterilization commonly used in CSSDs and SPDs. However, many autoclaves require substantial amounts of water and energy to operate, which is costly and can hinder sustainability initiatives. When choosing an autoclave, it’s essential to look for one with built-in sustainability features and includes specialized cycles designed to reduce both water and energy consumption.

The Top 8 Hospital Sterilization Cycles

Every autoclave comes with several pre-programmed sterilization cycles, each one designed to support a different application. Some autoclaves even offer operators the ability to program custom cycles depending on the types of loads their CSSD or SPD most frequently sterilize. These sterilization cycles vary in terms of time, temperature, pressure, and the inclusion of vacuum and/or exhaust phases.

Some of the most common hospital sterilization cycles used in CSSDs and SPDs include:

• Gravity Cycle: One of the most commonly used sterilization cycles, a gravity cycle pumps steam into a chamber of ambient air. This steam rises to the top of the chamber, displacing the air, which is forced out through a drain vent. The steam then penetrates the load, sterilizing it. It’s worth noting that gravity cycles often leave sterilized items wet, which is why gravity cycles are often accompanied by a post-vacuum cycle to dry goods off.
• Vacuum Cycle: A vacuum cycle uses a series of alternating steam pressure injections and vacuum draws (known as pulses) to remove air from the autoclave chamber. This enables steam to penetrate the load more fully than a gravity cycle, making this cycle a good option for sterilizing porous items, such as surgery packs. As with a gravity cycle, you can follow a vacuum cycle with a post-vacuum cycle to ensure goods are thoroughly dry upon retrieval.
• Liquid Cycle: A liquid cycle is what it sounds like: a cycle intended specifically for liquid loads. The liquid cycle avoids boil-over by releasing the chamber pressure slowly through the exhaust phase, allowing the liquid load to gradually cool as the surrounding chamber pressure decreases.
  
• IUSS Cycle: IUSS cycles are intended for the urgent sterilization of instruments needed for immediate use. Popular in hospitals, ASCs, and other healthcare facilities, IUSS cycles are performed at elevated temperatures of 270°F–275°F (132°C–135°C), which means they’re able to sterilize goods at much faster rates than traditional gravity or vacuum cycles.
• Steam-Air-Mix Cycle: A steam-air-mix cycle is an advanced sterilization method designed for applications where standard cycles, such as gravity, liquid, and vacuum, might not be suitable. This cycle is especially effective at sterilizing liquid-filled containers, such as syringes, because it introduces compressed air into the autoclave chamber to balance internal and external pressures without increasing the steam temperature, thereby preventing the liquid from expanding.
• Air Over-Pressure Cycle: Designed to sterilize small liquid loads that are extremely sensitive to evaporation or boil-over, an air over-pressure cycle adds compressed air to the autoclave chamber to maintain the surrounding pressure of the liquid while the air temperature drops, thereby preventing evaporation. This type of hospital sterilization cycle is most commonly used for small pre-filled vials, loosely capped flasks, foil sealed glassware, or any partially vented containers where even small amounts of evaporation are not acceptable.
• Low-temperature Cycle: Ideal for load types that cannot withstand high temperatures, low-temperature cycles can run between 158°F–212°F (70°C–100°C) to accommodate heat-sensitive and heat-coagulable goods. Common applications for this type of cycle include endoscopes and microscopes, complex instruments with internal lumens, and devices made from composite materials.
• Rapid Cool Cycles: Rapid cool cycles are designed to increase efficiency by reducing the amount of time operators must wait before safely removing sterilized goods from the autoclave chamber. There are technically two types of rapid cool cycle — rapid spray-cool and rapid jacket-cool — both of which circulate cold water once sterilization is complete to quickly the temperature of the autoclave chamber.

Choosing the Right Hospital Sterilization Cycle

It’s imperative that technicians in CSSDs and SPDs choose the appropriate sterilization cycle for each load, otherwise they risk improper and incomplete sterilization, damage to equipment, regulatory and compliance, and an increased risk of patient infection.

When selecting a hospital sterilization cycle, consider the following:

• Material Compatibility
  • Does the load include porous materials or liquids?
  • Are any of the items in the load heat-sensitive or otherwise fragile?
• Load Characteristics
  • How large is the load? Does it include any dense packaging?
  • Are these goods reusable (and will therefore require reprocessing in the future) or single-use?
  • What are the lengths and widths of lumens in the load?
• Time Constraints
  • Are these goods needed for immediate use?
• Manufacturer’s Instructions for Use
  • Do the items in the load or the piece of equipment you’re sterilizing come with manufacturer’s instructions for use (IFU)?
  • If so, does the IFU specify a particular sterilization method or cycle type?

If you need help choosing the right hospital sterilization cycles to use in your central sterile supply department or sterile processing department, give Consolidated Sterilizer Systems a call. Manufacturing autoclaves since 1946, we can help you select the right cycle for any application — and our advanced X1 controller system makes it easy to create and store up to 50 custom, pre-programmed cycles based on your most frequent loads.