Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Process control in response to analysis
Reexamination Certificate
2001-03-19
2002-10-22
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Process control in response to analysis
C422S028000, C422S031000
Reexamination Certificate
active
06468469
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to methods of determining a reuse period for a chemical disinfectant composition and methods of reusing a high level disinfectant without retesting efficacy of the active ingredient.
BACKGROUND
Instruments that are used in diagnostic or therapeutic procedures, which encompass surgical, medical, dental, etc. procedures, require decontamination to remove microbial contamination. Depending upon the ultimate use of the instrument, different degrees of decontamination are required.
As used herein, decontamination is the removal of hazardous or unwanted materials such as bacteria, mold spores or other pathogenic life forms and the like, wherein high-level disinfection and sterilization represent different levels of decontamination. Sterilization is a level of decontamination representing the complete elimination or destruction of all forms of microbial life, including fungal and bacterial spores. High-level disinfection is a level of decontamination representing elimination of many or all pathogenic microorganisms, with the exception of bacterial spores, from inanimate objects.
Regulatory agencies and other groups have classified medical devices, processes, and cleaning and decontaminating products according to basic principles related to infection control. Medical devices are classified as critical, semicritical or noncritical. Critical devices, for example, scalpels, needles and other surgical instruments, enter sterile tissues or the vascular system. Such devices require sterilization with a process or with prolonged contact with a sporicidal chemical prior to reuse. A common way to sterilize critical devices is by exposure to heat. However, some instruments such as flexible lensed endoscopy instruments, inhalation therapy equipment, and other instruments and materials cannot withstand heat and must be treated with chemical solutions to achieve disinfection or sterilization. Such chemical solutions have included aldehydes, such as glutaraldehyde or o-phthaldehyde, or peracids.
Semicritical devices, for example, flexible endoscopes, bronchoscopes, laryngoscopes, endotracheal tubes and other similar instruments, are those that may contact any mucous membranes except dental mucous membranes. Such devices require high-level disinfection with a process or short contact with a sporicidal chemical prior to reuse. High-level disinfection can be expected to destroy all microorganisms with the exception of high numbers of bacterial spores. A Food and Drug Administration (FDA) regulatory requirement for high-level disinfectants is 100% kill of 100,000 to 1,000,000 (10
5
-10
6
) organisms of
Mycobacterium tuberculosis
(
M. tuberculosis
) in the presence of 2% horse serum in a quantitative tuberculocidal test. An additional FDA regulatory requirement for high-level disinfectants is that they must also achieve sterilization over a longer exposure time than the disinfection regimen time. Common high-level disinfectants include glutaraldehyde solutions between 2.4-3.4%
w/v
which also typically require activation with an alkaline buffer just prior to use, acidic hydrogen peroxide (H
2
O
2
) at 7.5%
w/v
(for example, Sporox®, Reckitt and Colman, Inc.), and an acidic mixture of 1.0%
w/v
H
2
O
2
and 0.08%
w/v
peracetic acid (PAA) (Peract™ 20, Minntech Corp. or Cidex PA®, Johnson & Johnson). The minimum effective PAA concentration for high-level disinfection at 25 minutes (min) and 20° C. is 0.05%
w/v
(500 ppm) (Peract™ 20). The minimum effective H
2
O
2
concentration for high-level disinfection at 30 min and 20° C. is 6.0%
w/v
(Sporox®).
High-level disinfecting solutions are typically designed for a reuse option, depending upon the type of device treated with the solution. The FDA currently approves the period during which a high level disinfectant may be reused. For example, the FDA has authorized a glutaraldehyde high-level disinfecting solution for endoscope reprocessing to be reused for as long as 28-30 days. The principle reason for reusing a solution is economic, as the practice itself provides the opportunity for adding to the risk of transmission of infection. The practice of reusing a high level disinfectant solution often results in a slow, continuous dilution of the solution over time, due to the inadvertent carry-over of rinse water into the disinfection solution. This rinse water may be present due to precleaning and rinsing prior to disinfection.
Medical devices such as thermometers and hydrotherapy tanks are also classified as semicritical, but they require intermediate-level rather than high-level disinfection prior to reuse. Intermediate-level disinfection inactivates
M. tuberculosis,
vegetative bacteria, most viruses and most fungi, but does not necessarily kill bacterial spores. A common intermediate-level disinfectant is Cavicide® (Metrex Research Corp.), which contains 0.28%
w/v
diisobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride, (a so-called super quat) and 17.2%
w/v
isopropyl alcohol.
Noncritical medical devices, for example, stethoscopes, tabletops, bedpans, etc., touch intact skin and require low-level disinfection prior to reuse. Low-level disinfection can kill most bacteria, some viruses, and some fungi, but it cannot be relied upon to kill resistant microorganisms such as tubercle bacilli or bacterial spores. Contact lenses are included in the class of devices which require low-level disinfection prior to reuse. Common low-level disinfectants for contact lens disinfection include acidic 3.0%
w/v
H
2
O
2
and 1-10 ppm solutions of polymeric antimicrobial biguanides or quaternary ammonium compounds (e.g., 1 ppm polyhexamethylene biguanide in Complete® (Allergan Pharmaceuticals, Inc.) or 10 ppm Polyquad™ polyquaternary ammonium compound in Optifree® (Alcon, Inc.).
Standards for sterilization and low, intermediate and high-level disinfection have been concurrently established. These standards are based upon the known or possible risk of contamination of a particular medical device by a particular microorganism, the pathogenic nature of the organism and other principles in infection control. They typically require demonstration of sterilization and/or disinfection efficacy against a particular panel of test organisms, which collectively represent the known or possible contamination and infection risks. The test panels and criteria are different for low, intermediate or high-level disinfection. It is also generally accepted that a high-level disinfectant will meet the disinfection efficacy standards of intermediate and low-level disinfection as well. It is universally accepted that low-level disinfection performance cannot predict intermediate or high-level disinfection performance. In fact, it is assumed prior to testing that a low-level disinfectant cannot achieve a higher level disinfection standard. Additionally, other factors such as device compatibility with the disinfection system must also be considered. The current medical device industry practices for semicritical medical devices (i.e., those that contact intact skin and all but dental mucous membranes) such as endoscopes involve separate short cleaning and disinfecting steps and times, and reusable solutions. Longer soak cleaning or disinfecting times and single-use solutions would for the most part be impractical and uneconomical in the current environment.
Currently, the only way to be assured that a high level chemical disinfectant is, in fact, achieving high level disinfection is by daily monitoring of the disinfectant solution. For example, the solution may be monitored by using a test strip that is impregnated with or otherwise contains chemicals reactive with one or more active components of the solution. Generally, a color reaction occurs in the presence of a threshold concentration of a chemical decontaminant, which indicates to the user that the chemical is at a concentration sufficient to achieve its stated level of decontamination. This concentration is frequently reported as the minimum effective concentration (MEC). The results
Conley Sean E.
Metrex Research Corporation
Warden, Sr. Robert J.
Wood Herron & Evans LLP
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