Decontamination Solutions for Medical Instruments

Disinfecting or sterilizing reused medical equipment kills most bacteria, fungi, viruses and other contaminants. Depending on the equipment, different varieties of sterilization methods are best to remove dangerous disease-causing microscopic agents. Any tool used for entering tissue or vascular systems needs sterilization before each use. As of 2010, moist steam-heat, gas, bleaches and dry heat remain the methods most used by hospitals and medical facilities globally. Chemical sterilization for heat-sensitive medical devices, such as fiber-optic endoscopes, is also common.

Autoclave Steam Heat

• Charles Chamberland's 1879 invention of the autoclave revolutionized pressurized sterilization of medical, dental, and surgical tools. The high-temperature steam, which reaches temperatures above water's boiling point, destroys or inactivates damaging and life-threatening viruses, bacteria, spores and fungi. Capable of producing temperatures of 1500 degrees Fahrenheit under 2000 psi (pounds per square inch) pressure, most autoclaves also contain secondary systems of water-cooling, vacuum and pressurization supplies.

Chemical Sterilants

• Peracetic acid (pictured) is one important sterilant for medical equipment.

  Peracetic acid sterilization removes primarily protein surface contaminants from endoscopic tubing, which medical professionals use to examine the interior parts of the body in procedures such as colonoscopies. Invented in 1988 and used generally in the United States, the automated machine employs a 35 percent peracetic acid solution combined with an anticorrosive agent in a single-dose container. Puncturing the container allows filtered water to dilute the acid to 0.2 at a temperature of 50 degrees centigrade. This thinned-down acid solution circulates through the machine chamber, then pumps through the endoscope tubing for 12 minutes, resulting in decontamination of all exterior surfaces, including fiber optic light, or lumens, and other endoscopic accessories. Rigid endoscopes without flexible tubing can be decontaminated by being placed in a lidded container that is plunged into the flowing sterilant, filling the lumens, or by directing the flow through channel connectors.

Gas Plasma

• Early in the 1980s, because of the limitations of ethylene oxide gas and steam to sterilize medical, surgical and dental equipment, a new method developed using low-temperature hydrogen peroxide gas vapor plasma. The result of this breakthrough system for sterilization of medical equipment leaves no toxic residue behind. The method uses a special chamber that is evacuated to reduce internal pressure, then injected with hydrogen peroxide. The liquid peroxide in the chamber becomes gaseous and removes harmful bacteria from the exposed surfaces of the medical tools placed inside. Second and third cycles ensure optimal decontamination. Venting the chamber equalizes the pressure, so the cleaned equipment can be used immediately, with no need for a cool-down or airing out the chamber.

Bleach

• Bleach is a widely used method of disinfecting medical equipment.

  Globally, bleach is used 77 percent of the time in sterilization of medical equipment and surfaces. A solution of one part bleach to 100 parts water disinfects surfaces including reusable thermometers, stethoscopes, needles and syringes. Emerging Third World countries often rely on bleach as their only means of destroying harmful microscopic organisms on medical equipment.