Section IV. CHEMICAL DISINFECTION
a. General. A disinfectant may be defined as the physical or chemical means to
remove or reduce the capacity of microorganisms to produce disease. Disinfectants do
not destroy most viruses or resistant bacterial spores. As a method of preparing items
for use in patient care areas, including the operating room, its use should be restricted
to those items that would be damaged or destroyed by sterilization means. Chemicals
are used to disinfect, not to sterilize. Disinfecting floors, furniture, and portable
equipment with chemicals make these reasonably safe to use.
b. Principles of Chemical Disinfection. The following principles should be
observed when you use chemicals to disinfect.
(1) All items to be disinfected must be clean. Organic soil (such as tissue,
blood, feces) makes the chemical inactive.
The exposure time must be adequate.
(3) The strength (concentration) of the chemical solution must be lethal for
microorganisms. The concentration of the solution determines its effectiveness.
The disinfectant must be safe to handle.
The disinfectant must not be harmful to the item being disinfected.
A disinfectant may be good for one item but not for another.
c. Selection of Chemical Disinfectants. There are a variety of disinfectants
available in CMS. The most common ones are discussed in the following paragraphs:
(1) Alcohol. As a disinfectant, it must be in a solution but it is useful both as
an antiseptic and as a disinfectant. For alcohol to be effective, the item must be totally
immersed for not less than 30 minutes. Alcohol will not kill bacterial spores. Since
alcohol is volatile, its use has been restricted.
(2) Formalin. A solution of formaldehyde gas and water is known as
formalin. Formalin and alcohol solution used by the military requires 30 minutes to kill
bacteria and tubercle bacilli and 12 hours for spores. Some of the disadvantages of
formalin include irritating fumes and irritation of tissue.
(3) Iodine-alcohol combinations and iodophors. These two chemicals
combined increase the effectiveness of both substances and decrease the exposure
time required to kill microorganisms but it stains.