NCCT TS-C Tech in Surgery – Certified

Sterilization is the complete elimination of all forms of microbial life, including bacterial spores. Various methods are used depending on the nature of the items being sterilized.

Steam sterilization is the most common and preferred method for heat- and moisture-stable items. It uses saturated steam under pressure to kill microorganisms. The standard parameters are 250°F (121°C) for 15-30 minutes at 15 psi, or 270°F (132°C) for 3-10 minutes at 27 psi (prevacuum).

Gravity displacement autoclaves use steam entering at the top to push air out through a drain at the bottom. Prevacuum (dynamic air removal) autoclaves use a vacuum pump to remove air before steam injection, providing faster penetration and shorter cycle times. Immediate-use steam sterilization (IUSS), formerly called flash sterilization, is used for emergency situations when an instrument is needed quickly. Standard IUSS parameters are 270°F for 3 minutes for unwrapped non-porous items.

Ethylene oxide is a gas sterilant used for heat- and moisture-sensitive items. It penetrates packaging materials and kills microorganisms by alkylation. Temperature ranges from 85°F to 145°F. Humidity of 30-80% is required for microbial kill. Exposure time ranges from 1-6 hours. Aeration time of 8-12 hours is required to remove toxic residue. EtO is toxic and flammable, requiring special safety precautions.

This low-temperature method is used for heat-sensitive items. Hydrogen peroxide vapor is energized into a plasma state by radiofrequency energy. The process typically takes 28-75 minutes. No aeration is required as byproducts are water and oxygen. Limitations include inability to sterilize liquids, powders, and cellulose-based materials.

Peracetic acid is a liquid chemical sterilant used for immersible heat-sensitive items, particularly endoscopes. The STERIS system is commonly used. Processing time is approximately 30 minutes. Items must be used immediately as they cannot be stored after processing.

Ozone (O3) is converted from medical-grade oxygen. It is low-temperature and leaves no toxic residue. Processing time is approximately 4.5 hours. It is suitable for moisture-sensitive items.

Dry heat is used for items damaged by moisture, such as powders, oils, and petroleum-based products. Higher temperatures (320°F-340°F) and longer exposure times (1-2 hours) are required compared to steam sterilization.

Glutaraldehyde is a high-level disinfectant that can achieve sterilization with prolonged exposure (10 hours). Standard high-level disinfection requires 20-90 minutes depending on concentration. It is used for heat-sensitive semi-critical items. It has a strong odor and requires adequate ventilation. Items must be thoroughly rinsed after processing.

OPA is a high-level disinfectant with faster action than glutaraldehyde. It requires 12 minutes at 20°C for high-level disinfection. It has less odor and is less irritating than glutaraldehyde. It may stain proteins, including skin and mucous membranes.

Hydrogen peroxide in concentrations of 7.5% is used as a high-level disinfectant. Processing time is approximately 30 minutes. It is less toxic than glutaraldehyde.

Woven textile wrappers (muslin) allow steam penetration but require double-wrapping. Non-woven wrappers (disposable) are single-use and available in various materials including spunbond-meltblown-spunbond (SMS) and spunlace. Paper-plastic pouches (peel packs) allow visualization of contents. Rigid container systems are reusable and environmentally friendly.

Holes, tears, or punctures compromise sterility. Moisture contamination (strike-through) renders packages unsterile. Compression during storage can break seals. Improper sealing leaves packages vulnerable. Expired sterilization date indicates the need for reprocessing.

Visual inspection checks for holes, tears, and moisture. Seal integrity must be complete without gaps. Chemical indicators should show appropriate color change. Labels must include sterilization date, contents, and sterilizer identification.

Class 1 (process indicators) indicate exposure to the sterilization process. Examples include autoclave tape that changes color. Class 2 (Bowie-Dick test) verifies air removal in prevacuum sterilizers. Class 3 (single-parameter indicators) respond to one critical parameter. Class 4 (multi-parameter indicators) respond to two or more critical parameters. Class 5 (integrating indicators) respond to all critical parameters. Class 6 (emulating indicators) respond to specific sterilization cycles.

Chemical indicators provide immediate results but do not prove sterilization. They indicate that conditions for sterilization were met.

Biological indicators (BIs) contain living spores that are highly resistant to sterilization. They are the only method that proves sterilization has occurred. Geobacillus stearothermophilus is used for steam and hydrogen peroxide sterilization. Bacillus atrophaeus is used for ethylene oxide and dry heat sterilization.

BIs should be used at least weekly for steam sterilizers and with every load for implants. Results are typically available in 24-48 hours, though rapid-readout BIs provide results in 1-3 hours.

The Bowie-Dick test is performed daily in prevacuum steam sterilizers. It verifies adequate air removal and steam penetration. The test pack is placed in an empty chamber for a specified cycle. Uniform color change indicates proper function.

The DART test evaluates air removal efficiency in prevacuum sterilizers. It uses a chemical indicator to detect air pockets. The test should be performed according to manufacturer recommendations. Results indicating air retention require sterilizer maintenance.