Microorganisms on instruments and drapes that come into contact with body fluids pose a risk of infection to both mothers and neonates. These instruments must be sterilized before use. Neonatal tetanus is just one common example of a disease that is often transmitted on instruments, but others include HIV and hepatitis.
Mechanism of Action
Several sterilization techniques are used, including ethylene oxide gas, hydrogen peroxide gas plasma, peracetic acid immersion, and ozone, but, globally, steam sterilization remains the most common method for the resterilization of hospital instruments.
Steam sterilization is commonly performed inside a heated pressure vessel known as an autoclave. In most cases, 30 minutes at 121°C is sufficient, but high performance “flash” autoclaves can reach higher temperatures and pressures, reducing sterilization times. A variety of power sources are used on steam autoclaves to heat the water to boiling against the pressure provided by the sterilization vessel. The simplest are electrically powered, but others are heated by natural gas, propane or even a wood burning stove.
Current Use in High-Resource Settings
Disposable products are increasingly common and typically come in sterile packaging, obviating the need for the caregiver to sterilize prior to use. For re-usable instruments, freestanding autoclaves with integrated (electrical or gas) heat sources are the most common sterilization technique in high-resource settings. A survey performed in the UK found that 82% of physicians used autoclaves for sterilization, 91% of which had been serviced within a year. High volume, front loading units are most common.
Application in Low-Resource Settings
“Stovetop” autoclaves are common in the developing world, even in clinics without electricity or water service. Typical heat sources include small, dedicated gas stoves and/or wood fires commonly used for cooking. Some 'disposable' plastic parts such as those which interact with a patient in ventilators may be chemically sterilized in some hospitals.