5.16:
Methods of Sterilization II: Chemical Methods
Chemical sterilization uses chemical sterilants to treat surgical instruments and medical supplies.
Each sterilant performs distinctively and has a specific purpose.
Ethylene oxide, or ETO, is a colorless gas that kills spores and microorganisms by interfering with their metabolic processes.
ETO sterilizers are used to decontaminate heat and moisture-sensitive devices, such as resuscitation bags.
The items are first cleaned and rinsed with demineralized water to remove contaminants, detergents, or tap-water residues.
Then they are put in packs, filled into baskets or carts, and placed inside the sterilizer chamber for a specified time.
During sterilization, numerous items absorb ETO.
These items must be aerated to allow evaporation and removal of residual ETO.
Liquid chemical sterilization is used for heat-sensitive, immersible, medical devices.
The devices are submerged in an active sterilant solution for a prescribed time at a controlled temperature and concentration to kill all possible microorganisms and their spores.
Then these devices are rinsed with water to clear the chemical remains.
Examples of sterilant solutions include formaldehyde, glutaraldehyde, and hydrogen peroxide.
5.16:
Methods of Sterilization II: Chemical Methods
In healthcare, the chemical method of sterilization uses chemical sterilants to treat surgical instruments and medical supplies to help prevent the transmission of infectious pathogens to patients. Due to heat sensitivity, most medical supplies and equipment should not be exposed to high temperatures. These parts include rubber, plastic, glass, and other similar elements.
Using chemical sterilization rather than heat to clean out equipment is recommended. It eradicates and removes all bacteria, viruses, and other pathogens using low-temperature chemicals. The substances used are either gases or liquids.
Medical devices are sterilized using various techniques, such as steam, dry heat, radiation, ethylene oxide gas (ETO), vaporized hydrogen peroxide, and other sterilization agents such as glutaraldehyde, formaldehyde, alcohol, peracetic acid, hydrogen peroxide, and iodophors.
The chemicals mentioned above have a wide range of applications. Some can be integrated with other different chemicals. Others are directly applied, and a few chemicals are used with steam sterilization in certain circumstances.
Hospitals widely prefer ethylene oxide sterilization, the only technique that effectively sterilizes medical devices without causing damage. It is used to sterilize medical devices made of particular polymers (such as plastic or resin), metals, or glass. ETO sterilization can also be used on devices that have multiple layers of packaging, or are located in difficult-to-reach areas, such as catheters. The basic ETO sterilization cycle has five stages: preconditioning and humidification, gas introduction, exposure, evacuation, and air washes, excluding aeration time.