By Steven G. Richter, PhD, RAC, SM(NRM)
Reusable medical devices come in all shapes and sizes, from specula to colonoscopes. Generally, these devices have expensive compo-nents that require them to be cleaned and disinfected or sterilized. This article describes the salient points for validating that a medical device can be safely reused. It covers disinfection processes, not sterilization. The cleaning validation information contained within is germane to all reusable medical devices.
Recently, the U.S. Food and Drug Administration (FDA) began requiring additional information on 510(k) submissions, demanding clarity in the options afforded to practitioners. Microbiologists generally treat all medical devices equally, even though many devices require special treatment.
Historically, manufacturers were not required to validate that cleaning and disinfection processes were effective in reducing microbial and protein loads to safe levels. The FDA may have asked manufacturers for data regarding disinfectant use during reprocessing. Frenetically, manufacturers would perform cursory simulated-use tests that may not pass muster with FDA reviewers today.
Currently the FDA requires validation studies for both disinfection and cleaning. These studies are important to the manufacturer because they will validate the safety and efficacy of the disinfection process. It is important to qualify both the cleaning and disinfecting processes prior to validation activities. This article will help the practitioner determine the best practices for performing these pivotal studies.
Synopsis of Standards
On its Web site, the FDA recognizes many consensus standards [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/search.cfm].
These standards can be used to support the study protocols and the FDA data (questions) requirements. Currently, the FDA recognizes the following AAMI/ANSI standards:
- ST-79 Comprehensive guide to steam sterilization and sterility assurance in healthcare facilities
- ST-81 Sterilization of medical devices: Information to be provided by the manufacturer for the processing of medical devices that can be re-sterilized
- ST-58 Chemical sterilization and high-level disinfection in healthcare facilities
The FDA places the primary responsibility for developing and validating methods for effective reprocessing of a reusable medical device on the manufacturer of the device. The manufacturer is expected to validate that the device can be cleaned and disinfected or sterilized adequately to allow the device to be reused. As outlined by the FDA, the manufacturer must test and validate any labeling claims of fitness for reuse that are provided in the instructions for the handling, cleaning, disinfection, packaging, and sterilization of medical devices in a health care facility. To demonstrate compliance with label claims, manufacturers of cleaning agents must validate that their cleaners provide the expected level of soil removal and also must determine their materials’ compatibility. AAMI TIR30 addresses the issues related to manufacturers’ validation testing for cleaning medical devices.
Other applicable documents include:
- AAMI TIR12: Designing, testing, and labeling reusable medical devices for reprocessing in health care facilities: A guide for medical device manufacturers
- AAMI TIR30: A compendium of processes, materials, test methods, and acceptance criteria for cleaning reusable medical devices
- AAMI TIR7: Chemical sterilants and high-level disinfectants: A guide to selection and use
- ASTM E1837-96: Standard test method to determine efficacy of disinfection processes for reusable medical devices (simulated use test)
- ASTM E-2314-03: Standard test method for determining the effectiveness of cleaning processes for reusable medical instruments using a microbiological method (simulated-use test)
There obviously is a degree of confusion regarding these standards in terms of continuity and compliance. So how do you set up a test protocol and make it worst case for validation purposes? This article is aimed at helping practitioners with the operation portion of cleaning and disinfection validation studies.
Each medical device is different in its principle, engineering, and body contact area. The cleaning and disinfection studies can be performed as a single element or a combination of elements (simulated use). Some FDA reviewers are asking for all of these studies. Therefore, it is important to define your parameters prior to 510(k) submissions.
First and foremost, the cleaning and disinfection processes should be qualified prior to validation. These notebook studies can be invaluable for setting the procedures for successful validation outcomes. Qualification studies are worked out with the reuse study project manager. The following are important aspects of this process:
- Challenge material: soil choices and bacterial species
- Cleaner type: enzymatic category (lipase, proteinase)
- Presoak/soak contact time and water temperature
- Water quality (pH and hardness)
- Brushes for manual cleaning
- Pre-cleaning rinse
- Post-cleaning rinse
- Drying time and temperature
- Pass/fail criteria: log reduction or acceptable levels
- Disinfectant classification: low/intermediate/high
- Use dilution and storage
- Immersion and flushing for disinfectant 100% product contact
- Time and temperature
- Water quality (pH and hardness)
- Rinse method (sterile water)
- Pass/fail criteria (log reduction)
Cleaning Studies: Points to Consider
Technical Information Report (TIR) 30 is the penultimate cleaning document used in the medical device industry. This report contains a com-pendium of test methods and acceptance criteria for the cleaning of reusable medical devices. Some pertinent information is indicated below.
Enzyme cleaners work best within a narrow pH and temperature range. Various enzyme cleaners are used for medical devices. Protei-nase/lipase dual-enzyme lichen-based enzyme cleaners are the general choice of most manufacturers. Manual cleaning elements are broken down into the following categories:
Each element has a beneficial effect on the removal of body fluids, tissues, or excrement, such as saliva, blood, stool, urine, mucus, protein and fat.
The challenge soil should approximate the exposure level of bacteria and body fluids and tissues. A device will require a thorough analysis of potential cleaning based on worst-case scenarios in order to achieve a robust and comprehensive study outcome.