Sterilization is a crucial part of almost any process that occurs in the lab. It is vital because only sterilized instruments can provide a successful outcome of any surgical operation.
The rules of cleaning, disinfection, and sterilization are known to all medical personnel and are not supposed to cause any confusion. But those who have no relevant background or are just beginning to learn the basics of the lab work have a hard time figuring out what’s what. When students need to come up with lab reports or other detailed papers on related topics, they may decide to ask others for help or even give the project over to others. While it is a good way to save time, we highly recommend that you study it yourself as well by reading this detailed guide to sterilizing your instruments.
The process of cleaning surgical instruments is divided into three main stages: cleaning, disinfection, and sterilization. Let’s talk about each of them in detail.
Cleaning your Instruments
Cleaning removes all dirt and biological material from the instruments. It is very important to clean your instruments thoroughly, because even the tiniest amount of dirt left on instruments can corrupt the results of your research or even ruin it completely.
There are two types of cleaning; manual and mechanical. In both cases, you can use water, detergents, or enzymatic cleaners. Enzyme detergents react with biological material, which makes them ideal for cleaning your lab instruments. They also cope well with oils and fats.
Firstly, rinse off all dirt, blood, and tissue from the instrument in cool water. If needed, soak it in a detergent or an enzymatic cleaner. Then, you can wash them either manually or mechanically.
If your tools can be easily damaged or need to be disassembled before cleaning, it is better to clean them manually. Remember about the safety measures. Always wear rubber gloves and an apron. It is also advisable to put on safety goggles or a mask.
Choose only neutral pH cleaners. Detergents that contain a low level of pH can stain your instruments if they are improperly cleaned. Alkaline fluids can also cause brown staining on the instrument’s surface.
Refrain from using abrasive materials or harsh brushes for cleaning. They can ruin the smooth surface of the instrument and blunt its cutting edges as well. Instead, use soft plastic brushes that will keep the instrument both clean and undamaged.
Once you have cleaned the instruments, inspect them visually for any remaining dirt or stains. Make sure the instruments work well and then dry them with a soft cloth to prevent corrosion. Apply lubricants to the moving parts of your instruments to prolong their service.
It involves the same stages as manual cleaning but is performed by a machine. The process begins with cold water rinsing followed by a hot bath and another round of rinsing. Then, the instruments are dried with hot air.
Ultrasonic cleaning is one of the most common ways of cleaning surgical instruments mechanically. Sound waves cause vibration in the cleaning fluid and create bubbles which implode and make the dirt come off even in very difficult-to-reach places. Once the instruments are clean and dry, lubricate the hinges with a special medical lubricant.
Disinfecting your Instruments
The next step is disinfection. In most cases, surgical instruments are heat-resistant. It makes boiling one of the most effective ways of disinfection which kills almost all microorganisms. However, you should keep in mind that boiling does not sterilize your instrument.
There are several basic rules that you should follow while disinfecting through boiling.
Put the instruments in the boiler and switch it on. Once the water starts boiling, switch on the gentle boiling mode. It will prevent your instruments from being damaged against one another. Let the water boil for one minute and then turn the boiler off. Use only sterile tongs to get the instruments out of the water. Otherwise, your disinfection will be vain.
Do not leave the instruments in the water for a long time, either. Once they cool off, they may get contaminated again. Use distilled water to prevent limescale buildup on your instruments. Or you can simply add a drop of white vinegar to regular water.
Chemical disinfection should be applied if your instruments are heat-sensitive. Among the most widely used chemicals are hydrogen peroxide, glutaraldehyde, peracetic acid, and ortho-phthalaldehyde.
Depending on the level of contamination, surgical instruments may need to undergo one of the three stages of disinfection: Either high-level, intermediate-level or low-level disinfection.
- High-Level Disinfection or HLD: This type of disinfection eliminates almost all microorganisms and spores. Remember, though, it is not sterilization.
- Intermediate Level Disinfection or ILD: This procedure is aimed at killing almost all viruses, mycobacteria, and tubercle bacilli.
- Low-Level Disinfection or LLD: It is carried out to get rid of lipid viruses, some fungi, and vegetative bacteria. However, it is useless against tubercle bacilli.
Sterilizing your Surgical Tools
Sterilization aims to kill all bacteria. Even the most resistant forms cannot withstand the process. The most frequently used ways to sterilize instruments are autoclaving and dry heating. However, chemicals like hydrogen peroxide and ethylene gas are also used in the process of sterilization.
Sterilizing in an Autoclave
Clean and lubricate your instruments before putting them into an autoclave. Use only special medical lubricants. Do not use WD40 or any other industrial lubricants.
Put the instruments into an autoclave in an open position. Heat makes metal expand, which can damage locked instruments. Do not stack the instruments in the chamber. Place them carefully on a piece of cloth leaving some space between them.
You can autoclave the instruments in a sterile piece of cloth or simply unwrapped. The difference is that the wrapped instruments must be processed a bit longer.
With the autoclaving finished, take out the trays with the sterile items. Now the instruments should be used immediately. It is also acceptable to store the sterilized items in a warm, dry, and covered place for up to a week.
Using Dry Heat for Sterilization Purposes
Sterilizing with dry heat is a lot like autoclaving but it is applied when you need to sterilize items sensitive to moisture.
Use sterilizing pouches or wrap your instruments into a piece of foil, or just lay the items on the tray. Put the batch into the oven and follow the manufacturer’s instructions on how to sterilize the instruments in dry heat.
How Sterile Should My Instruments Be?
All surgical equipment can be divided into critical, semi-critical, and non-critical. This classification allows us to define how sterile the items must be.
Critical equipment interacts with the patient’s sterile tissues or blood. Such instruments pose a great risk of infecting, that is why they must be exposed to thorough sterilization.
Semi-critical instruments interact with mucous membranes and do not penetrate sterile tissues. It is enough for such items to undergo high-level disinfection as mucous membranes are not sensitive to small amounts of microorganisms.
Non-critical instruments come in touch only with the bare skin. Such equipment must be thoroughly cleaned, but there is no need to sterilize them.