Medical device designers must ensure that their non-patient-contacting medical equipment surfaces can be cleaned and disinfected.
By Mike Neilson
A technician wipes a touch screen monitor with a lint-free cloth during a disinfection validation.
When you hear the term “reusable medical devices,” you may think of instruments like retractors or scopes. Reusable devices often have intimate patient contact, become grossly soiled during clinical use, and need to be reprocessed before their next use. Manufacturers of reusable medical devices are aware that these types of devices require cleaning and sterilization processes to be validated before the devices can be sold to healthcare facilities.
What is often less understood is that medical equipment used in healthcare settings inside and outside of the operating room—such as hemodialysis machines, wall mount drug delivery systems, and probe docking stations—may require similar cleaning and disinfection validations. The AAMI TIR 12:2010 discusses the risk associated with medical equipment surfaces that are likely non-patient-contacting. It states that these devices “can contribute to secondary crosscontamination by the hands of healthcare workers or by contact with medical instruments that will subsequently come into contact with patients.”1
Crosscontamination is a growing concern in healthcare settings, as patient infections continue to be prevalent. FDA expects cleaning and disinfection validations to be performed for any equipment surface in a patient care setting that may become contaminated with blood-borne pathogens or other potentially hazardous organic material. This includes adjustment knobs, handles, carts, cables, touch screens, monitors, and keyboards.
Subject matter experts at Nelson Laboratories have seen a dramatic increase over the past year with non-patient-contacting medical equipment validation requests. They have found that reprocessing validations for equipment surfaces can sometimes be tricky.
Problems arise when medical equipment is designed for functionality with little thought for ease and effectiveness of cleaning and disinfection. This is particularly true of non-patient-contacting devices. While patient-contacting devices are typically made of materials that are easy to reprocess, non-patient-contacting surfaces are often made of polymeric materials that may not be compatible with some detergents or chemical disinfectants. Design features that make reprocessing difficult—such as seams where two components meet, ridges on knobs, textured handles, or logos that extrude from or are imprinted into surfaces—are often included. It is also problematic when a device cannot be disassembled to reach contaminated areas. Although design features may improve usability, they can also make removal of organic material extremely difficult.
Problematic equipment designs are common. Sometimes, companies are ready to submit their product to FDA, and then they have to redesign some feature that just can’t be effectively cleaned.
Cleaning validations typically follow the guidance outlined in AAMI TIR 30:2011 and FDA’s Draft Guidance for Processing/Reprocessing Medical Devices. These validations consist of challenging a test article with a test soil that simulates a worst-case clinical contamination.2, 3 The test articles are then cleaned following the manufacturer’s prescribed procedure, extracted, and tested for residual organic materials. When performing these validations for reusable devices, there are a variety of validated test soils that contain clinically relevant constituents in order to simulate blood, mucosal fluid, and other organic contamination. This becomes more difficult for an equipment surface where worst-case soiling is less defined and could entail a variety of organic materials. In addition, the amount of soil applied in validations is difficult to define for surfaces that should not routinely see any significant soiling.
Cleaning solutions are also more difficult to determine. While traditional reusable devices are processed by hospital sterile processing departments, non-patient-contacting equipment surfaces are generally cleaned at the point of use. Equipment manufacturers must consider what types of cleaning products will be readily available to end users in the clinical setting. Although cleaning validations are considered to be a separate process from disinfection validations, incorporating combination disinfectant-detergent products that are becoming more commonly used in healthcare settings can blur the line. The processes, however, should still be tested separately, as cleaning validations evaluate the effectiveness of a process to remove organic soil and disinfection validations evaluate the effectiveness of a process to kill various levels of organisms that may remain on a surface after cleaning.
Disinfection validations typically follow the guidance outlined in AAMI TIR12:2010 and consist of inoculating a test article with high concentrations of representative or worst-case challenge organisms. Medical devices and equipment are categorized as critical, semicritical, and noncritical (Spaulding classification) according to the risk of infection from contamination on the item.4 Based on categorization, different levels of disinfection (high, intermediate, or low) with differing performance criteria may be required. Most equipment surfaces are non-patient-contacting and thus, by Spaulding Classification, are termed as noncritical devices. FDA recommends intermediate or low-level disinfection for noncritical devices depending on the nature and extent of contamination.
Unfortunately, standard processes and procedures used for testing reusable devices often won’t work for equipment surfaces. You end up over challenging the surface or creating a situation that is not clinically relevant. For this reason, a customized approach to this testing can be beneficial. In this approach, scientists consult with manufacturers to write test protocols explicitly designed to meet the specific product’s needs. This is required to create feasible and clinically relevant soiling and cleaning/disinfection scenarios that will lead to the necessary FDA approvals.
In May 2011, FDA presented a draft guidance document defining FDA expectations as far as reprocessing validations and instructions to the end user are concerned.3 Though the guidance is not yet finalized, it is important for equipment manufacturers to understand FDA’s expectations as far as product labeling is concerned. The document contains “FDA’s seven criteria for reprocessing instructions.” The critieria are summarized here:
Following this guidance will aid medical equipment manufacturers in obtaining the appropriate regulatory approvals to get their products to market. In many cases, FDA requires manufacturers whose equipment is already on the market but deficient in validated cleaning and disinfection instructions to bring their products up to current expectations. Because of this, there has been an increase in validations being performed on postmarket approval products.
Infection control in the healthcare setting continues to be a pressing issue for FDA, as evidenced by the expanding scope of reprocessing validations, change in hospital reimbursement models based on hospital acquired infections, release of the FDA draft guidance document on reprocessing validations, and the increase in cleaning and disinfection validations being performed. It is important that equipment and device manufacturers alike become more aware of the potential crosscontamination risks in the clinical setting, validate to those risks, and then provide sufficient instructions to follow the validated process.
1. AAMI TIR12:2010, “Designing, Testing and Labeling Reusable Medical Devices for Reprocessing in Health Care Facilities: A Guide for Medical Device Manufacturers” (Arlington, VA: , 2010).
2. TIR30:2011 “A Compendium of Processes, Materials, Test Methods, and Acceptance Criteria for Cleaning Reusable Medical Devices” (Arlington, VA: AAMI, 2011).
3. FDA, “Draft Guidance for Industry and FDA Staff—Processing/Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling,” [online] (Rockville, MD: FDA, 02 May 2011); available from Internet: http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/....
4. E.H. Spaulding, “Chemical Disinfection and Antisepsis in the Hospital,” International Journal of Hospital Research, 9:5-31, 1972.
Mike Neilson is senior quality specialist at Nelson Laboratories.