Everything there is to know about sterilization tubing.
Sterilization is a process of the absolute removal of germs, including bacteria, fungi, and viruses, from products and an environment. It is a compulsory process in the manufacturing of sterile medical materials, devices, and sterile pharmaceutical products. There are various kinds of methods. They include heat sterilization (dry and wet), gaseous sterilization, chemical methods, and the use of radiation.
Sterilization tubing is used for encasing items to be sterilized while maintaining the integrity of the sterilized items. They mostly contain chemical indicators that notify when the process has been completed. In some instances, they may be used to dispense the sterilized products. They are used for both dry and wet heat sterilization processes.
History of sterilization tubing
The act of sterilization began in the late 19th century. Charles Chamberland developed the first pressure wet heat sterilizer (or autoclave) in 1876. Robert and Koch and his teammates researched extensively on steam or hot air to kill germs and microorganisms, and their work led to the development of a no-pressure/flowing steam sterilizer. Through this, the boiling of medical materials with the aim of absolute disinfection became popular. The sterilization of medical materials, notably wound dressings, was first demonstrated by a German scientist, Ernst Von Bergmann, in 1885.
Over the 20th century, noticeable improvements were observed in sterilization methods. They include the introduction of a chemical method (mainly glutaraldehyde), the use of radiation (ultraviolet rays were first used), and the gaseous method (ethylene oxide). There were newer advances in steam sterilization too.
Sterilization tubing was also introduced in the 20th century. They may be nylon-made or paper-plastic combinations and are used together with a heat seal. They have shown excellent capability as packaging materials in the maintenance of the sterility of equipment and products.
Indications to use sterilization tubing
Sterilization is necessary to ensure the total absence of microorganisms from medical equipment and sterile pharmaceutical products. Sterilization tubing is a packaging material that maintains the sterility of equipment during and after sterilizing. Typical sterilizing procedures involve multiple equipment or products. So, sterilization tubing serves various roles which include:
- An encasing wrap material
- Process monitoring- most contain chemical indicators that change color when the process is complete.
- Prevention of contact amongst the different items being sterilized
- Prevention of contact between the contraindicated parts of the chamber and the item being sterilized
- Prevention of contamination during handling
- Maintenance of sterility after the processes
They are unique properties an ideal tubing must possess. These properties include:
- Penetrability or aeration- it must allow the sterilant to penetrate and access the equipment or product. Likewise, it must allow the gas (such as ethylene oxide) to dissipate thoroughly for gaseous methods.
- Provision of effective barrier
- Drapability, transparency
- Ease of use, flexibility
- Puncture-resistant, high tear strength
- Non-toxic or presence of odor
Sterilization tubing is used mostly for dry and wet heat sterilizations. These two methods are the most reliable. It is less commonly used for chemical and gaseous methods.
This is done by exposing the item of interest, and consequently, any microorganisms present to saturated steam under pressure. The steam penetrates the organisms and causes denaturation of enzymes and structural proteins. This method requires the control of the time of exposure, pressure, and steam temperature. Sterilization can be achieved at a steam temperature of 126 - 129℃, 2.5 atm pressure, and for a minimum exposure time of 10 minutes. It could also be achieved at a temperature of 134 - 138℃ and 3 atm pressure for a minimum exposure time of 5 minutes.
Dry air method
The use of hot, dry air causes oxidation of cellular constituents of microorganisms, thereby killing them. This method employs higher temperatures and longer exposure time. So, it is suitable for thermostable equipment and non-aqueous products that cannot survive steam sterilization. The minimum exposure time is 1 hour 30 minutes at the temperature of 160℃, while at 180℃, it is only 30 minutes.
This method involves the use of volatile gases like ethylene oxide. These gases are highly flammable and toxic; hence they are always mixed with inert gases before use. The concentration of the gas, humidity, and time of exposure are the most critical parameters in this method.
Chemicals used for this method include glutaraldehyde, formaldehyde, ozone, hydrogen peroxide, peracetic acid, and so on. Some products may be thermolabile and unstable to heat. They may also be unsuitable for gas methods or readily damaged by irradiation. Such products or equipment may be sterilized through this method.
Complications of sterilization tubing
A few complications can arise from the use of these materials. For instance, the material may burst or tear up. This may be due to oversized equipment, improper sealing, an irregular cycle, and the exposure time. The presence of air inside the enclosure before sealing can cause nylon tubing to burst during use. The presence of moisture in the package after the whole procedure may also indicate the wrong usage mentioned earlier.
Also, when a nylon tubing is placed touching the sterilizer's metal component or an incorrect sterilizing temperature is being used, they may be found molten together or around the sterilizer.
Sterilization tubing should not be removed before the end of the process. The sterilizer should be tightly closed too. It is worthy to note that these materials are for single-use. Adherence to all of these prevents complications.
Alternative materials may include rigid containers, heat-sealed or self-sealing paper or plastic pouches, roll stock or reels, and woven or unwoven sterilization wraps.
All of these are less desirable alternatives. Sterilization tubing offers top-notch use specifications, and the presence of a chemical indicator aids the monitoring of the sterilizer performance.
General specifications of a sterilization tubing
The general specifications of a paper-plastic material include:
- Material- premium medical grade paper with plastic film at the edges
- Seal- double or triple seal, self-sealed or heat-sealed
- Size- each rolls of varying width sizes
- Chemical indicators- they are mostly external indicators. There are separate ones for steam, ethylene oxide, and so on. The indicators may change color or darken.
- Shelf life- 4-5 years
- Post usage shelf life is typically six months.
The general specifications of a nylon tubing include:
- Material- transparent nylon films
- Seal- typically used with heat sealers
- Size- presented in 100 feet roll of varying inch sizes
- Temperature- they withstand up to 140℃ in steam sterilizers and 190℃ in hot air.
- Chemical indicators- typical color change is green to blue, indicating that the package has been processed at standard temperatures and up to their minimum exposure times.
How sterilization tubing works
The proper width is selected based on the size of the equipment to be sterilized. After this selection, the tubing material is cut into the desired length based on the same criterion. One end of the material is then sealed using a heat sealer. The item to be sterilized is then put into the pouch enclosure. The item should cover about three-quarters of the pouch space. It is important to remove any excess air in a nylon tubing before sealing the other end. After this, the other end can be sealed using the heat sealer.
The package is then put into the sterilizer, and the cycle is commenced. Sterilizer trays can be lined with cloth or paper. When different pouches are to be sterilized, contact can be prevented through the use of paper or fabric in between pouches.
After completing the sterilizing cycle, the desired indicator change should be observed to confirm the item's exposure to the sterilizer. If there is no change, the cycle needs to be repeated under optimized conditions. The tubing should be allowed to cool for some minutes before handling it.
They are designed to allow the penetration of the sterilant (steam, hot air, gas, etc.) and the use of chemical indicators to confirm this. They possess other features that help in the disposal of their duties.
Some of the top manufacturers of sterilization tubing include:
- Septodont- Septodont is a leading manufacturer of medical devices. The company has been in existence since 1932 and is based in the USA.
- Defend- Defend is another industry-leading brand with many milestones and years of excellence. Defend has been established since 1985 and currently serves nearly 50 countries.
- Duraline- Duraline Systems Inc. is a top manufacturer of sterilization equipment and materials.
- CardinalHealth- Cardinal Health Inc. is a global company and a chief manufacturer of medical supplies and pharmaceutical products. The company is headquartered in Dublin, Ohio.
- Steris-Steris is also a top brand. The company was founded in 1985 in Ohio.
Sterilization tubing has revolutionized the process of sterilizing medical equipment and materials. They made multiple products sterilization possible, and also prevented non-microbial contamination of products. This could be in the form of allergens from sterilization chambers or incompatible equipment materials. They offer great value for their price.
They are currently well optimized in design and functions. However, scientific advancements in the whole process are not out of reach.