Hydrogen Peroxide for Sterilizing Medical EquipmentFaizan Khan
Sterilization is one of the oldest procedures known to mankind. It stems from the time human beings started to gain consciousness of things around them and determined cleaned ones are better than the filthy ones.
Medicine is just another field that requires extremely delicate procedures. And certain instruments and equipment are needed during these. And therefore it is not ideal or efficient to use new instruments every time healthcare workers operate on someone. Sterilization is the way to go.
Moreover, as the technology progresses, there are certain medicinal tools that are heat and moisture-sensitive. Therefore, the orthodox way of sterilization by heating becomes ineffective. A new emerging form of sterilization is being used nowadays called low-temperature sterilization.
Now the question arises, what are the best tools people can use to sterilize at low temperatures? Does the traditional yet effective hydrogen peroxide is as effective in cleaning medicinal tools as it is cleaning wounds at room temperature? And how can people incorporate it in their sterilization processes?
So without further ado, let’s begin!
Why Hydrogen Peroxide For Medical Equipment Sterilization?
There are dozens of potent disinfectants out there, yet hydrogen peroxide is primarily used for disinfecting medical equipment. Not a white bottle of bleach nor the potent ammonia chloride solution, the trusty brown bottle of hydrogen peroxide is only a vital first aid tool.
Why is that so? And what are the certain properties that hydrogen peroxide has that other disinfectants lack? The answer resides in the structure of hydrogen peroxide. Hydrogen peroxide is just like water but with an additional oxygen molecule. This extra oxygen molecule is responsible for a ton of utility hydrogen peroxide provides!
The oxidizing properties of hydrogen peroxide are one of the fundamental ones that make it so versatile. According to various doctors and research, oxygen is one of the best medicinal tools known to mankind. That’s because almost all of the biomolecules have some proportion of oxygen molecules which enable them to react with the additional oxygen species.
Even the most basic unit of life, the cell, has organelles that are sensitive to oxygen. The amount of oxygen is strictly regulated in the cells by various enzymes and processes.
With that in mind, hydrogen peroxide provides this amazing tool so easily. The oxygen-hydrogen peroxide is loosely bound and under normal environmental conditions, it dissociates into regular water and of course the reactive oxygen.
The oxidation property of hydrogen peroxide not only makes it a potent killer of microbes but also a versatile one. The bacterial and fungal cell walls are composed of simple lipids and proteins. Under the influence of oxygen, these products react and break down into simple fatty acid chains and amino acids.
Therefore, hydrogen peroxide can kill off all bacteria and germs easily and efficiently!
Another amazing property that is exclusively provided by hydrogen peroxide is the products of its reaction. This property is also hinted at in the above paragraph. What this means is, hydrogen peroxide is practically water when it liberates its reactive oxygen species, and water is the liquid of life.
When compared with other bleaching and disinfecting agents like bleach and ammonia, hydrogen peroxide stands out because of its simpler nature and the way it carries out its reactions. Bleach under certain conditions reacts to form chlorine, hypochlorous acid, and hydrochloric acid. All of these chemicals are extremely toxic and dangerous for human use. Similarly, ammonia reacts to form ammonium hydroxide which is an extremely strong base and corrosive.
And therefore, the property of hydrogen peroxide to liberate water and oxygen makes it a thoroughly used tool in industries as well as households. In the industry, hydrogen peroxide is preferred because the products it liberates are simple and do not hinder the reaction. In households and normal use, hydrogen peroxide does not put your health and skin under jeopardy by its use, unlike bleach and ammonia.
Ease of Availability
One last factor that seals the deal for hydrogen peroxide as an amazing disinfectant is how easily it’s available and how economical it is.
Hydrogen peroxide comes in all concentration forms. However, the brown 3% hydrogen peroxide solution is one of the most well-known first aid tools in the world. It is so common that someone not having a brown hydrogen peroxide bottle at home is considered a rarity.
Hospitals and households alike have limited fundings. Given that, cleaning is not something they want to spend loads on. And hydrogen peroxide provides people with an economical and more convenient alternative. Not only is it cheap and regularly available but it is also very easy to use (this is discussed further in the subsequent sections).
What is Hydrogen Peroxide Sterilization?
Before the 1950s, the primary way of sterilizing medical equipment was high heat sterilization, primarily steam sterilization to kill off microbes. However, the newer generation of medical equipment uses materials and minerals that are sensitive to high temperatures. Therefore, a newer way of low-temperature sterilization has developed.
One of the primary tools used in this type of sterilization is ethylene oxide gas, ozone, and hydrogen peroxide. Not only can these tools maintain the integrity of medicinal equipment but also can kill off heat-resistant microbes.
Nonetheless, hydrogen peroxide sterilization is a low-temperature sterilization process that is particularly effective for heat-sensitive devices. When compared to other low-temperature sterilization tools like ethylene oxide, hydrogen peroxide requires less time.
The process involves the filling of hydrogen peroxide inside an air-tight chamber which leads to the killing of microbes and bacteria. And like all hydrogen peroxide reactions, after the process is complete, the hydrogen peroxide vapors turn into water and oxygen and are then vacuumed away from the container.
As the name dictates, low-temperature sterilization is performed at lower degrees. However, one should not think that low temperatures mean freezing ones. The name is given as a comparison to the orthodox way of heat sterilization which uses high temperatures of 150-200 degrees celsius to work. In low-temperature sterilization, the temperature is maintained under 60 degrees celsius (regularly it works best at 37-44 degree Celsius range)
The substances that are used to perform this type of sterilization focus more on changing the composition of bacteria through different processes e.g. oxidation rather than denaturing its structure (as happens with high-temperature sterilizations).
The most commonly used low-temperature sterilant is ethylene oxide. A few decades ago, ethylene oxide was used as a mixture with CFCs. However, in view of CFCs’ adverse effect on the ozone layer, the use of CFCs is now banned. Now the available substitutes are either hydrogen peroxide or pure ethylene oxide.
The new sterilization technology uses gas plasma versions of hydrogen peroxide as a sterilant. Gas plasma is the fourth state of matter, more description of how it works is given in the subsequent sections.
Vaporized Hydrogen Peroxide Sterilization
Vaporized hydrogen peroxide sterilization is just another name for low-temperature sterilization using hydrogen peroxide. In this form of sterilization, hydrogen peroxide is used in the form of tiny vapors, which are later converted into a gas plasma state inside the chambers.
The Healthcare field has started using hydrogen peroxide more and more over ethylene oxide. That’s because hydrogen peroxide is a well-known disinfecting agent that people are confident in using. It is widely used in household settings, and people are comfortable with its non-toxic nature and byproducts.
Another reason which compels hospitals to use hydrogen peroxide over ethylene oxide is how efficient it is. Vaporized hydrogen peroxide sterilization only uses one utility and that’s power. Millions of dollars are saved from extra water, steam, or compressed air. All of these are provided by hydrogen peroxide, which itself is very cheap.
Equipment That Hydrogen Peroxide can Sterilize
Now that we know what exactly is hydrogen peroxide sterilization and what are some of its forms, we can discuss the medical equipment that can be cleaned with hydrogen peroxide.
The medical equipment comes in all shapes and sizes, however, we have divided them into three subgroups. Hydrogen peroxide is particularly proficient in cleaning these!
It goes without saying that surgical equipment is the one that pops into mind whenever we hear the word “medical tools”. And rightly so, because surgical types of equipment are also the ones that require extensive cleaning with proper care.
Surgery is one of the most popular and important medical procedures. And the whole process is as delicate as a feather. That’s because on the surface our body is a wall of protective tissues and cells. However, under surgical settings, those safety walls are breached and the body is left vulnerable to the pathogen attack. And sometimes, the surgeons operate on patients who have chances of being a host to plasma-borne diseases like HIV and hepatitis. Therefore, it is extremely important to have the operation room and surgical tools completely sterilized.
Some of the most common surgical tools that are cleaned using hydrogen peroxide are the cutting and dissecting instruments like scalpels, scissors, and saws. They are the ones that are directly inserted inside the body and need the most amount of cleaning.
Biopsy forceps are special types of L-shaped medical equipment which are used to obtain tissue samples for screening. More particularly, it is used for nasal and esophageal tissue extraction. In addition to obtaining the tissue samples, it is also used for removing foreign objects that may be stuck inside the nose or ears.
As one might guess from reading its description, the biopsy forceps invade the inner mucosal surfaces of the body. These are sensitive areas for pathogenic attacks. And if the biopsy forceps are not sterilized properly, they can catch severe forms of infections.
Moreover, it is also important that the sterilizing agent should be harmless and compliant with the sensitive mucosal surfaces. And only hydrogen peroxide comes into mind that is both effective and preserves the body from catching infections.
Implanted Medical Devices
Naturally, our bodies are equipped with all the necessary tools needed to operate properly. However, after years of wear and tear or due to some birth defect, a need for a foreign intervention arises. These interventions that are implanted inside and aim to aid the body’s normal functioning are called implanted medical devices.
Quite similar to the case with surgical tools, these equipment come in direct contact with viscera (organs). And as the body is vulnerable at that level, the tools should be properly sterilized and germ-free. Installment of uncleaned medical devices inside the body may lead to systemic infections and sepsis and in turn, multiple organ failure, which is an extremely serious condition.
Some of the most commonly implanted medical devices include cardiac pacemakers, hip implants, coronary stents, and implantable insulin pumps. All of these are placed inside delicate organs like the heart and pancreas.
What Concentration of Hydrogen Peroxide is Ideal for Sterilization?
Hydrogen peroxide comes in all forms of concentrations and proportions. However, the most popular one is the 3% hydrogen peroxide solution. This is also the one which is widely used inside our homes for disinfecting and cleaning purposes.
That’s because, at this concentration, the hydrogen peroxide is strong enough to kill germs and inhibit bacteria, and not corrosive enough to cause any skin or body damage. Moreover, as this concentration is widely available and is cheap, people opt to pick up the brown bottle of hydrogen peroxide solution for all types of cleaning purposes.
However, it is to be noted that the sterilizing equipment you have mentions the ideal concentration of hydrogen peroxide in its manual. Make sure to give it a read and determine the best concentration for your machine.
Hydrogen Peroxide Sterilization – The Procedure
Now that we have familiarized ourselves with the low-temperature sterilization process, we can move on to the nitty-gritty of the whole process. Although the whole process is fully automated and takes place inside heavy machinery, there are a lot of things to know about the process.
As mentioned above, the form of hydrogen peroxide used is a special form of gas plasma. The gas plasma version of hydrogen peroxide is formed inside an enclosed chamber under a deep vacuum. Then, these particles are excited to higher energy levels by using radiations in the form of radio or micro frequency waves. This excitation of hydrogen peroxide releases many free radicals as a product.
Free radicals are those atoms that have an unpaired electron and are extremely reactive. Therefore, the said mechanism of action produces free radicals inside the vacuum which can interact with essential cell components (e.g. enzymes, nucleic acids) of microbes. This leads to disruption in their metabolic functions and in turn, eliminates them.
The effectiveness of this procedure depends on two factors: the depth of the vacuum and the type of seed gas used. The depth of vacuum is available in different sizes depending on the type of instrument you want to clean. And the most common seed gas used is hydrogen peroxide and ethylene oxide. The reason is that both of these compounds have loosely bound oxygen atoms (which provide an excellent free radical species) and can easily form plasma under radiations.
According to experts, the hydrogen peroxide solution is inserted inside the chamber using a cassette to a concentration of 6 mg/l. The hydrogen peroxide then takes about 50 minutes to completely diffuse throughout the chamber and thoroughly covers the surface of the instruments. Then through an automated process, the electrical field gives off radiation and converts these vapors of hydrogen peroxide into free radicals which start to react with microorganisms.
In the final step of this process, the excess air is eliminated by introducing high-efficiency filtered air. The great thing about hydrogen peroxide is that the byproducts are harmless forms of water and oxygen and thus, the instruments can be handled safely. Moreover, the chamber does not require any additional aeration because of the non-toxicity of byproducts.
On a general note, the whole process operates at a temperature range of 37-44 degrees celsius and has a cycle time of 75 minutes.
Some Safety Guideline
Governmental organizations like FDA (Food and Drug Administration) as well as ISO (International Organisation for Standardization) have strict rules for the use of sterilization. Hydrogen peroxide is no exception to the rule that sterilants should be safe and effective.
The first safety protocol that hospitals have to follow is to ensure the safety of patients. In this regard, the medical instruments should be cleaned with proper ISO guidelines and remove any toxic residues that could be potentially harmful to the patients.
The next step is to ensure the safety of the sterilization drive that you may be using. However, the great thing about hydrogen peroxide is that it has excellent material compatibility with a plethora of materials.
One of the most crucial aspects of maintaining the safety protocol is ensuring the safety of the healthcare workers and those who are using the sterilizing equipment. The regulatory bodies of the United States and many other countries have put a limit on the exposure to the sterilant. As hydrogen peroxide is a relatively safe material to use, the threshold is relatively lower. The staff is expected to limit the hydrogen peroxide exposure to 1 ppm over an 8-hour Time Weighted Average. All members of staff are expected to adhere to this safety protocol and ensure a safe environment.
Speaking of which, the final aspect of following safety guidelines is ensuring the safety of the environment. The sterilant used should not be toxic to the environment or lead to pollution. One of the examples seen is the use of CFCs in early low-temperature sterilization processes. After its detrimental effects on the ozone layer were known, CFCs were replaced with pure ethylene oxide or hydrogen peroxide. By using hydrogen peroxide for low-temperature sterilization processes, many healthcare systems have checked this part of the safety protocol. That is because hydrogen peroxide breaks down into simple water and oxygen which are non-toxic to the environment as well as humans.
Challenges for Hydrogen Peroxide Sterilization Process
As with any form of handling chemicals, the performers should be wary of the challenges associated. Similarly, with vaporized hydrogen peroxide sterilization as well SPF personnel should know what challenges are faced during the process.
One of the drawbacks of using hydrogen peroxide in the sterilization process is that the size of the chamber is typically smaller than those of high-temperature sterilization ones. Steam sterilizer and autoclave have much bigger tanks that can disinfect a lot more instruments at a time.
Similarly, the load size is also limited in the low-temperature sterilization chambers. The manufacturer validation and the design of the device play an important role in the sterilization cycles and load limitations.
The heat and moisture-sensitive instruments are not always compatible with the vaporized hydrogen peroxide sterilizer and therefore, the department must confirm the device compliance with certain tools.
One thing to keep in mind is that the chambers used in the low-temperature sterilization process are highly moisture sensitive. They operate at stimulated vacuums and therefore if any moisture is present on the instruments the vacuum will not be achieved and the whole process stops. Therefore, another disadvantage, or rather difficulty people face with the use of low-temperature sterilizing machines is that they are highly moisture and heat-sensitive. So the instruments that are placed inside the chamber should be thoroughly cleaned, dried, and wrapped before starting the sterilization process.
The Final Verdict
According to many researchers and experts, low-temperature sterilization marks the modern way of disinfecting and cleaning medicinal tools. As they are used in highly delicate procedures, extensive care and efforts are required to properly sterilize them.
Hydrogen peroxide makes this task of people easier as well. It provides many advantages over other forms of heat-sterilization processes as well as low-temperature sterilization processes that do not use it.
Although there are some limitations to the use of the hydrogen peroxide sterilization process, overall the merits outweigh the drawbacks and hydrogen peroxide emerges as a superior tool in cleaning all sorts of medicinal instruments.
Therefore, get your hydrogen peroxide bottles today and enjoy cleaning!