Operation Theatre Cleaning, Disinfection And Sterilization

By: Akhtiar Ahmed Solangi


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I’m Akhtiar Ahmed Solangi. Today, I want to talk about something really important: keeping operating rooms clean and safe. It’s crucial for patients, and I’m here to shed light on “Operation Theatre Cleaning ,Disinfection and Sterilization.”

What makes a surgery successful:

As a seasoned professional with extensive experience in performing major surgeries, I firmly believe that the key to a successful surgical procedure lies in the unity and collaboration among all members of the healthcare team, including doctors, technicians, nurses, and sanitary workers. In the intricate dance of surgery, even the slightest deviation from established protocols or a single mistake can have dire consequences for the patient, potentially leading to severe harm or even death. It is a misconception to attribute the sole responsibility for a patient’s well-being to the surgeon; rather, it is the collective effort and unwavering unity of the entire team that safeguard and enhance the chances of a successful surgery, ultimately preserving and improving lives.

When cleaning of OT is performed?

 Infection Control: Cleaning the operating theatre and surroundings is crucial to prevent infections for patients and healthcare workers.

Cleaning Schedule: It follows a routine:

 Before Surgery: Getting the operating theatre ready.

 Daily: Cleaning before surgeries begin.

 Between Patients: After one surgery, before the next.

 End of Day: Thorough cleaning after the last surgery.

 Periodic Deep Cleans: Weekly or monthly for high hygiene standards.

 Comprehensive Cleaning: Every area, from the operating theatre to scrub areas, recovery rooms, and sterilizing areas, gets thorough cleaning.

 Step-by-Step: The process flows logically:

 Start: Cleaning begins in the operating theatre.

 Progress: Continues through scrub areas and recovery rooms.

 Finish: Ends in the sterilizing area.

 Final Detail: Even the toilet is cleaned meticulously, the last step in this careful process.

Methods of Disinfection of Operation Theatre:

1)Bleach 2)Formaldehyde 3)Alcohol 4)Hydrogen Peroxide

And there are many disinfection methods but these 4 are main.


What is bleach?

In an operating theatre (OT), bleach, typically sodium hypochlorite, is often used as a disinfectant and cleaning agent. Sodium hypochlorite is a chemical compound containing chlorine, and it is known for its strong disinfecting properties. When diluted with water to an appropriate concentration, it can effectively kill a wide range of microorganisms, including bacteria, viruses, and fungi.


 bleach 100% NaOCl?

Hypochlorite concentration in household bleach varies by manufacturer. Many household bleach solutions contain 5.25% sodium hypochlorite, and a 1:10 dilution (5250 ppm Cl) will produce a 0.53% hypochlorite solution1.

What is sodium hypochlorite 12.5% used for?

SODIUM HYPOCHLORITE 12.5% is a commercial bleach used to remove stains, whiten, kill germs and deoderise. It can be used in all areas of the home and finds many uses in all industries.


What is Formaldehyde

Formaldehyde, in its liquid and gaseous states was used as a disinfectant as well as sterilant. However, its disagreeable odor and irritant fumes even at very low levels limited its use. Despite being a high level disinfectant, it is no longer used in most hospitals because of its role as a suspected human carcinogen. Water-based solution of formaldehyde is available and is called formalin.

A number of environment friendly products like ammonia, baking soda, borax, and vinegar were evaluated as alternatives for disinfectants but were found to be unacceptable.


Formalin Solution: Formalin is a solution of formaldehyde gas in water, typically containing between 10% to 37% formaldehyde. The concentration used in disinfection can vary, but it’s often diluted with water to achieve the desired concentration for a specific application. For example, a 10% formalin solution may be used for disinfecting surfaces or equipment.


What is Alcohol

Alcohol, particularly isopropyl alcohol, is commonly used to disinfect surfaces and equipment in the OT. It is effective in killing a wide range of microorganisms, including bacteria, viruses, and fungi. Surgeons and healthcare professionals may use alcohol-based solutions to clean their hands before surgery and to disinfect the patient’s skin at the surgical site.



Alcohols, water soluble compounds refer to ethyl or isopropyl alcohol. These are best used at concentration of 70 to 90% by volume. They require a wet contact for at least 5 min to disinfect. Wiping with alcohol is a low.level disinfection. Ethyl alcohol is a potent bactericidal agent and inactivates viruses including hepatitis B (HBV) in 15 min and human immunodeficiency virus (HIV) in 1 min. Isopropyl alcohol is equally effective on bacteria, but lacks effectiveness against non-lipid enteroviruses. They are considered as intermediate or low level disinfectants because of their inability to inactivate bacterial spores and because of the inability of isopropyl alcohol to inactivate hydrophilic viruses. Alcohol is often used to clean external surfaces of fibreoptic cables. As alcohol evaporates rapidly, it is not necessary to rinse the items which are soaked in it.

Use of alcohol-based rub before and after every patient contact is recommended as it reduces bacteria count more rapidly compared to any antimicrobial soaps. Alcohols being flammable must be used with care if any heat source is present in the vicinity.

4)Hydrogen Peroxide

What is hydrogen peroxide

Hydrogen peroxide, often referred to as H2O2, is a chemical compound commonly used in the operating theatre (OT) and healthcare settings for various purposes, primarily as a disinfectant and antiseptic.


Hydrogen peroxide has bactericidal, virucidal, sporicidal, and fungicidal properties. Although most microbial forms are killed in less than 1 h, it takes hours to eliminate spores. It should be stored in a cool place and protected from the light. High level disinfection can be achieved in 30 min using a 7.5% solution, whereas 3% solution is a low level disinfectant that can be used for inanimate surfaces. Higher concentrations are corrosive to metals. It has been currently used with nebulisation system for decontamination of operating room.



Methods of Sterilization of Operation Theatre:

1)Ethelyne Oxide 2)Gama Rays 3)UV Rays 4)Formaldehyde

And there are many sterilization methods also.




1)Ethelyne Oxide

What is Ethelyne Oxide

Ethylene oxide (ETO or EtO) is a colorless, flammable gas commonly used in the healthcare industry for the sterilization of medical equipment and devices that are sensitive to heat, moisture, or radiation. This method of sterilization is known as ethylene oxide sterilization.


The concentration of ethylene oxide (ETO) used in sterilization processes can vary depending on several factors, including the specific equipment being used, the type of materials being sterilized, and the sterilization cycle conditions. Generally, ETO gas concentrations used in sterilization typically range from 450 to 1,000 milligrams per liter (mg/L) or parts per million (ppm). Here are some common concentration ranges:

*Low Concentration ETO (450-600 mg/L or ppm): This concentration range is often used for sterilizing heat-sensitive medical devices, such as certain plastic or electronic components. Low-concentration ETO cycles are typically longer to ensure thorough sterilization.

Medium Concentration ETO (600-800 mg/L or ppm): *Medium-concentration ETO is employed for a wide range of medical devices, including items with complex shapes and materials like rubber and some types of plastics.


*High Concentration ETO (800-1,000 mg/L or ppm): High-concentration ETO is used for sterilizing devices that are difficult to penetrate due to packaging or other factors. It may also be used for equipment with long lumens or channels, such as endoscopes.

2)Gama Rays

What are Gamma Rays

Gamma ray sterilization is a method used to sterilize various items in an operating theatre (OT) environment, particularly those that are sensitive to heat, moisture, or other sterilization methods. Gamma rays used in this context are a form of ionizing radiation, and they serve as an effective means of killing microorganisms on medical equipment and supplies.

Exposure Time

The exposure time for gamma ray sterilization in a specific application can vary depending on several factors, including the type and strength of the gamma radiation source, the density and composition of the material being sterilized, and the desired level of sterilization.

Gamma ray sterilization is a process commonly used to sterilize medical equipment, pharmaceuticals, and other products. It involves exposing the items to gamma rays emitted from a radioactive source, typically cobalt-60 (^60Co) or cesium-137 (^137Cs).

The exposure time is determined by a combination of factors, including the dose of radiation required to achieve the desired level of sterilization and the rate at which the gamma rays are delivered. The sterilization dose is typically measured in grays (Gy), where 1 Gy is equivalent to 1 joule of energy absorbed per kilogram of material. The required dose for sterilization depends on the specific product and the microorganisms it needs to be sterilized against.

Exposure times can range from a few minutes to several hours or more, depending on the factors mentioned earlier. The goal is to ensure that a sufficient dose of radiation is delivered to kill or inactivate the target microorganisms while maintaining the quality and integrity of the sterilized product.


3)UV Rays

What are UV Rays?

UV rays, or ultraviolet rays, are a type of electromagnetic radiation with shorter wavelengths than visible light but longer wavelengths than X-rays. UV rays are commonly used in sterilization processes to kill or inactivate microorganisms such as bacteria, viruses, and fungi. This sterilization method is referred to as ultraviolet germicidal irradiation (UVGI).

Exposure Time

The exposure time for UV ray sterilization can vary widely depending on several factors, including the type and strength of the UV-C radiation source, the distance between the source and the target, the intensity of the UV-C light, and the specific microorganisms you are trying to sterilize.

Typically, for small-scale UV-C sterilization devices used in applications like disinfecting surfaces or purifying water, exposure times can range from seconds to several minutes. However, the exact exposure time should be determined based on the manufacturer’s guidelines and the specific requirements of the sterilization task.

It’s important to note that UV-C sterilization effectiveness is influenced by factors such as the UV-C dose delivered, the cleanliness of the surface or material being sterilized, and the angle and distance from the UV-C source. Therefore, the exposure time should be calculated to ensure that a sufficient UV-C dose is delivered to achieve the desired level of sterilization while considering these variables.

In commercial and industrial settings, UV-C systems are often designed, tested, and validated to ensure proper sterilization performance, and exposure times are established accordingly. Always follow the manufacturer’s recommendations and guidelines for the specific UV-C sterilization equipment and application you are using to ensure effective and safe sterilization.


What is Formaldehdye?

Formaldehyde is a chemical compound with the formula CH₂O. It is a colorless, strong-smelling gas at room temperature and is commonly used in various industrial and laboratory applications, including as a disinfectant and sterilizing agent. Formaldehyde is considered a high-level disinfectant and sterilant because of its effectiveness in killing or inactivating microorganisms, including bacteria, viruses, and fungi.

Formaldehyde-based sterilization processes are often used for heat-sensitive medical instruments and equipment that cannot withstand high-temperature sterilization methods such as autoclaving. The process typically involves using formaldehyde gas or solutions containing formaldehyde.


The concentration of formaldehyde used for sterilizing operating theaters (OTs) or other medical facilities can vary depending on the specific sterilization process and equipment being used. Formaldehyde gas, which is commonly used for sterilization in OTs, is typically generated from a solution called formalin. The concentration of formalin used to produce formaldehyde gas for sterilization can range from 37% to 50% formaldehyde.

Formaldehyde gas sterilization is used for the high-level disinfection and sterilization of critical medical devices and equipment that cannot be heat-sterilized, such as certain surgical instruments. The formaldehyde gas concentration, exposure time, and temperature are carefully controlled to ensure effective sterilization while minimizing potential risks associated with formaldehyde exposure.

The actual concentration and exposure parameters for formaldehyde gas sterilization in an OT or medical facility should be determined based on established guidelines, manufacturer recommendations, and relevant regulations. Moreover, it is essential to adhere to proper safety protocols and ensure adequate ventilation to protect healthcare personnel and patients from exposure to formaldehyde gas, as formaldehyde can be harmful when inhaled or in contact with the skin or mucous membranes.


As a professional with experience, I can confidently state that the same considerations for cost-effective sterilization alternatives can be applied to UV rays, gamma rays, and ethylene oxide (EtO) sterilization on one side, with formaldehyde on the other side.

UV Rays, Gamma Rays, and Ethylene Oxide (EtO): UV rays, gamma rays, and EtO sterilization are all widely used methods in healthcare and industry, each with its own advantages and cost implications. When choosing among these methods, factors such as cost, equipment availability, material compatibility, and safety are key considerations.

– UV Rays: UV sterilization can be effective for surface disinfection but may not penetrate opaque or shadowed areas. It is relatively cost-effective and safe when applied correctly.

– Gamma Rays:Gamma ray sterilization is highly effective but can be costly due to the need for specialized equipment and facilities. It’s typically used for items that can’t withstand heat.

– Ethylene Oxide (EtO): EtO is effective and suitable for heat-sensitive equipment. However, it requires specialized equipment and safety measures, and the cost can be a significant factor.

*Formaldehyde: Formaldehyde-based sterilization methods, as discussed earlier, can be cost-effective and practical, particularly in regions with budget constraints. Formaldehyde is known for its effectiveness against microorganisms and is suitable for heat-sensitive items.

The choice between these methods depends on the specific needs and resources of the facility. Cost, safety, effectiveness, and the nature of the items being sterilized all play a role in determining the most appropriate sterilization method. Regardless of the method chosen, it’s crucial to adhere to guidelines and regulations to ensure safety and infection control in healthcare settings.

Triacid-N one of the best Surgical Instrument Disinfectant Solution:

Triacid N, also known as Triaminoaminonitroxyethane, is a chemical compound with the molecular formula C3H10N4O4. It is a nitrogen-rich organic compound containing three amino groups (NH2) and one nitrooxy group (ONO2). Triacid N is sometimes used as a stabilizer or fuel additive, particularly in the context of rocket propulsion or explosives, where it can release nitrogen gas and contribute to combustion and thrust.

It’s worth noting that compounds like Triacid N are often used in specialized applications and should be handled with care due to their potential explosive properties and sensitivity to shock and heat. Proper safety precautions and handling procedures are essential when working with such compounds.

Concentrations for

-(Incl HIV/HBV/HCV) 1.0% 15min

-Vaccinia Virus 1.0% 15min

-Bovine viral Diarrhea 0.5% 5min

-(Tuberculocidal.mycobactericidial) [1.0% 15min] [0.5% 30min] [0.25% 60min]

Timeline of OT Safety Practices

*1847: Sir Ignaz Semmelweis implemented a strict handwashing policy for medical personnel using a chlorine solution.

*1867: Dr.Joseph Lister first identified airborne bacteria and used carbolic acid in surgical area

*1880: Sir Johnson introduced antiseptic surgical dressings

What is wrong with our Disinfectant using practices:

 Disinfectants used indiscrimately.

 Used unnecessarily.

 Not used when needed.

 Not making proper concentrations.


Frequent Cleaning of OT Walls and Roof is not needed. why?:

 Frequent cleaning has little effect.

 Do not disturb these areas unnecessarily,

 Floors get contaminated quickly, depend on Number of persons present in the Theatre/Movements they make, has direct relation to increase of bacterial counts

Importance of staff education:

the education of operating theater (OT) staff is crucial for ensuring the safe and effective functioning of surgical environments. Here are some key points highlighting the importance of OT staff education:

 Patient Safety: Well-educated OT staff are better equipped to provide safe care to patients. They understand the importance of infection control, aseptic techniques, and proper handling of surgical instruments, reducing the risk of surgical site infections and other complications.

 Surgical Precision: Education enhances the technical skills of surgeons, nurses, and support staff, leading to improved surgical precision. This translates to better outcomes for patients and shorter recovery times.

 Efficiency: A well-educated OT team is more efficient in handling surgical procedures. They can anticipate surgeons’ needs, set up equipment quickly, and respond effectively to unexpected challenges during surgery.

 Adherence to Protocols: OT staff education ensures that all team members are aware of and adhere to established protocols and guidelines. This consistency in practice helps maintain high standards of care.

 Emergency Response: Education includes training for emergency situations, such as unexpected complications during surgery or equipment failures. Staff members who are well-prepared can respond calmly and effectively, potentially saving lives.

 Innovation and Technology: OT staff education keeps professionals updated on the latest surgical techniques and technologies. This knowledge allows for the incorporation of innovative procedures that may lead to better patient outcomes.

 Communication: Effective communication is essential in the OT. Education programs often focus on teamwork, collaboration, and clear communication among OT staff members, reducing the risk of errors and misunderstandings.

 Continuous Improvement: Education encourages a culture of continuous improvement. OT staff members are more likely to engage in self-assessment, peer review, and professional development to stay current in their fields.

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