What is Sterile Processing for Hospitals and Laboratories?

Sterile processing (SP) involves every procedure employed to make surgical instruments safe. It is vital to daily medical or dental operations because sterile equipment is the first defense line against infections. According to the Centers for Disease Control and Prevention (CDC), sterilization errors account for 75% of surgery-related deaths, 20% of surgical site infections, and prolonged hospital stays. As a result, extra effort is being made in the healthcare system to alleviate these risks with sterile processing. This process ensures adequate cleaning, storage, inspection, and sterilization of surgical instruments.

Here, we'll discuss the sterile processing department and the procedures, including decontamination, assembly and packaging, sterilization, and quality assurance. Read on.

Sterile Processing Department 

The sterile processing department (SPD), also fondly called the central supply department or the central sterile services department, is a section of a healthcare facility where surgical instruments are cleaned and sterilized for safe use. This department also caters to aseptic processes like wound bandaging, stitching, and catheterization.  

With the activities of the SPD, there is a reduced risk of instrumental or postoperative infections in patients and surgical staff. This reason is that these infections do not only increase morbidity but may lead to death.

In the SDP, various instruments and devices are subject to different procedures depending on their use and material. But typically, after the surgical staff uses a tool, it undergoes four primary processes in this order; decontamination, assembly and packaging, sterilization, and quality assurance. These procedures are carried out by no one but a sterile processing technician. 

However, a phase before sterile processing is the collection of dirty tools full of bacteria and spores. This phase is the riskiest for healthcare workers and SP technicians. Hence, these tools must be placed in trays without cracks and welds so that the residues, which are naturally lost, do not nest in them, causing clots of hazardous germs.

During this collection phase, operators must wear scratch-resistant gloves, protective clothing like face masks, and goggles to protect themselves from splashes of contaminated substances.

The Decontamination Process

This is the initial phase of SP, as only clean instruments are sterilized. Decontamination is the step that aims to make the pathogenic organisms on the devices inactive. Also, it involves dissembling and inspecting the instruments for damage. This operation can be carried out manually or mechanically. However, tools that require disassembly need first manual and then mechanical cleaning.

Manual cleaning

Manual cleaning is done by hand by the SP technician. The choice of manual cleaning depends on various reasons. First, it may be the recommendation of the instrument’s manufacturer. On the other hand, the tool may require manual cleaning before mechanical. Also, this process is used for powered devices that may not fit into automated washers. Lastly, SP technicians resort to this method if the facility lacks an automatic washer.

Manual cleaning is done in a double or triple-bay washing sink or scrub sink. Usually, one of the bays contains enzymatic and detergent solutions. Then the technician brushes the tools by hand to eliminate residual dirt. The other bay is used to rinse the tools. While rinsing may seem simple, it is crucial. Because while the residual pathogens can represent a danger, the traces of detergent are hazardous to the patients on whom these tools will be used. Hence, it is good that technicians rinse with clean and demineralized water.

Some of the sinks available on medwish.com include:

●     Hospital Scrub Sink For Operating Theatre with Stainless Steel Material DGER-72B

●     Stainless Steel Water Sinks With Mirror In Hospital AG-WAS009

Mechanically clean

Today, hospitals and analysis laboratories prefer specific machinery rather than manual washing. Unlike manual cleaning, these machines are programmed to complete instrument cleaning. Thus, they facilitate productivity and consistent cleaning. Common examples include ultrasonic cleaners, automated washing machines, and thermal disinfectors.

Ultrasonic cleaners are used for sensitive tools that may not fit into regular disinfectors. They work based on cavitation. In this process, high-frequency sound waves run through a solvent, usually water, creating a void or bubbles. The resulting bubbles then break on the surface of the immersed tool, including blind holes to scrub adhered germs. 

A variety of ultrasonic cleansers are available on Medwish. Examples include:

●     DL–120B Ultrasonic Cleaner

●     DG-CL32 ULTRASONIC CLEANING MACHINE（3.2L）

●     Multiple-Capacity Ultrasonic Cleaner DL-180D

Assembly and Packaging

After decontamination, the devices are then assembled and packaged. However, the materials are inspected before assembling to ensure every piece is properly clean. If necessary, lubricating products are applied to allow correct movement. Also, humidity on the equipment's surface favors the natural development of microorganisms. Therefore, all water traces must be removed. To achieve this, technicians use compressed air guns, paper, or canvas cloths.

Instrument packaging is usually done in a separate room from the decontamination area. It is essential to store the instruments in properly sealed packages to prevent contact with the environment and eventual contamination.

Sterilization

After packaging, the next step is sterilization. It is a process that destroys all forms of living microorganisms and residual biological agents on the equipment through chemical or physical methods.

Methods

• Steam sterilizer: The best-known and most used heat sterilizing agent is steam because it is fast, safe, economical, and has a good penetration capacity. The primary equipment for steam sterilization is the autoclave. It is used for materials that are stable to moist-heat, like glassware and metallic instrument. Materials in the autoclave are sterilized under a pressure of 15 pounds and a temperature of 121°C for about 30-60 minutes. The autoclave kills all forms of microbes, including resistant spores.

• Low-temperature sterilization: this method uses low temperatures with chemicals like ethylene oxide (EtO), Ozone, vaporized hydrogen peroxide, and liquid chemicals.

Ethylene oxide is used for products like catheters, metals, polymers, glass, and devices with surfaces that are hard to reach. This chemical impregnates the treated objects for a long time, up to four hours.

One of the latest sterilization methods is the use of Ozone. It is safe, eliminating microbes without toxic emissions. This extra oxygen atom is responsible for sterilization as it oxidizes microbes on reusable materials like water bottles and stainless-steel tools. The sterilization cycle lasts more than four hours at a temperature between 30-35°C. 

Vaporized hydrogen peroxide is the basis of one of the most advanced sterilization techniques. With this method, it is possible to treat plastics, metals, optical fibers, electronic components, and very delicate instruments. When applied in the gaseous state, hydrogen peroxide generates free radicals with a high germicidal capacity.

Sterilization with liquid chemicals involves using peracetic acid, which has antimicrobial properties. It is used for heat-sensitive instruments, especially those used in endoscopy.

• Dry sterilization: involves long exposure times of the instruments to hot air at very high temperatures. For an optimal result, it is necessary to reach a temperature of 160°C for one hour or 180°C for 30 minutes. This method is used on materials like powders, sharp tools, and petroleum products. The process employs the conduction mode of heat transfer. The material absorbs heat and circulates it across the surface till the desired temperature is reached. Dry heat achieves sterilization through oxidizing molecules. The equipment used for this sterilization includes hot air ovens and incinerators.

Quality Assurance

While all processes, from decontamination to sterilization, may seem to be done correctly, there is a need for confirmation; this is where quality assurance comes into play. Quality assurance ensures all sterilization parameters are met and materials are safe for use. And to achieve this, various indicators are used, including biological, mechanical, and chemical.

Biological indicators are most commonly used. The reason is that they assess sterilization by incorporating a known resistant sporulating bacteria species, Geobacillus or Bacillus. Sterility is confirmed when the bacteria is killed. The downside with biological indicators is that they are not fast, as results can take up to a week. On the other hand, mechanical and chemical indicators do not confirm sterility. However, they help detect anomalies in sterilization due to procedural or equipment defects.

FAQ

Is sterile processing difficult?

Yes. Sterile processing is a necessary procedure in every healthcare facility. However, not everyone can carry out this process as it is tasking and requires the expertise of a sterile processing technician. 

What are the steps in sterile processing?

Sterile processing involves four primary steps in this order; decontamination, assembly and packaging, sterilization, and quality assurance.

What are the three types of sterilization?

They include dry heat, moist heat, and chemical sterilization.

What are the five methods of sterilization?

The most commonly used sterilization methods in medical and laboratory facilities include:

● Steam sterilization

● Dry heat sterilization

● Gas sterilization

● Radiation

● Filtration 

Which equipment is used for sterilization?

Various pieces of equipment are used for sterilization depending on the materials. Examples include autoclaves, steam sterilizers, ethylene oxide sterilizers, plasma sterilizers, dryers, ultrasonic cleaners, etc.

Conclusion

The sterile processing is a vital procedure in healthcare. This procedure ensures every surgical and dental instrument is cleaned and inspected to be free of germs and pathogens. It involves decontamination, packaging, sterilization, and quality assurance. These processes are carried out in the sterile processing department by trained technicians.