The Manufacturer's Role in Safe Reuse

Medical Device & Diagnostic Industry Magazine
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An MD&DI May 1997 Column

DEVICE REUSE

With the increasing need for reusable devices, manufacturers need to validate safe reprocessing strategies for their products.

Several factors are at work in today's health-care market to encourage the reuse of medical devices, and as reuse increases, so too does the demand on manufacturers to ensure that their devices are safe even after repeated use and reprocessing. The current focus on cost containment and waste reduction in health-care facilities is a major factor behind the increase in reuse of devices. In fact, to cut costs, some hospitals are reusing and reprocessing devices intended for single use only. In a survey conducted recently by Infection Control & Sterilization Technology, 35% of the responding hospitals reported that they reuse single-use devices, primarily catheters, blades, and knives, and 43% reported that they reprocess such items.

At the same time, advances in medical technology have made it possible to produce more highly sophisticated and complex reusable instruments and devices. The reprocessing of these devices is also becoming more advanced. New sterilization technologies that are suited for use in health-care facilities have been developed, mainly to supplement or replace the lengthy ethylene oxide (EtO) process. These new procedures include plasma-based technologies, which provide the quick turnaround that is critical for maintaining low inventories of high-priced medical devices. Even though steam is still the sterilization process of choice, hospitals must also use other processes because many devices require low temperatures to maintain both material integrity and device function over the expected life of the device.

This reusable biopsy forceps from Olympus America, Inc. (Melville, NY) has reprocessing instructions to ensure sterility.

SAFETY RESPONSIBILITIES

As reuse continues to increase, who will be responsible for ensuring a sterile, functional device is used for every patient procedure? FDA places the primary responsibility on the manufacturer to develop and validate methods for effective reprocessing of its devices. Medical device manufacturers have long followed FDA rules in the manufacture of single-use devices by establishing and following GMPs, so it should be no surprise that FDA expects the same quality efforts from manufacturers in the design, testing, and labeling of devices for reuse. As outlined in the 1996 FDA reviewer guidance document, Labeling Reusable Medical Devices for Reprocessing in Health Care Facilities, any labeling claims of fitness for reuse provided in the instructions for the handling, cleaning, disinfection, packaging, and sterilization of medical products in a health-care facility must be tested and validated.

Once a device is in the hands of the end-user, however, no regulatory body oversees methods for its use and reuse. Hospitals are not bound by GMPs, although their reprocessing activities are informally guided by the recommended practices of the Association of Operating Room Nurses, American Society of Healthcare Central Service Personnel, Association for Infection Control, and, recently, the Association for the Advancement of Medical Instrumentation (AAMI).

Although these recommendations have been adequate for normal hospital processing in the past, the challenges of reuse of both reusable and single-use devices have resulted in the need for health-care personnel to coordinate with manufacturers and ensure that the necessary training and resources will be available to follow recommendations. There is a dual responsibility for safe reuse: manufacturers must recommend safe practices, and health-care facilities must ensure that the manufacturer's recommendations are diligently followed and that central service personnel are adequately trained to do so.

The AAMI TIR 12, Designing, Testing, and Labeling Reusable Medical Devices for Reprocessing in Health-Care Facilities: A Guide for Device Manufacturers, was developed jointly by manufacturers and hospital professionals to address mutual concerns and to develop standardized methods based on proven technology. This guidance document outlines for manufacturers standard hospital practices that are used in a reusable device life cycle.

A reusable device is one intended for repeated use on different patients with appropriate reprocessing between uses. The first element in a comprehensive reusable device program, therefore, is adequate design for ease of reprocessing. Hinged joints, small crevices, and narrow lumens will all interfere with adequate cleaning and sterilization of a device. Because devices will be subjected to difficult-to-remove soils, the ease with which the devices can be cleaned is critical to successful sterilization. The device design must enable cleaning of all areas; this often requires disassembly to access internal channels and narrow lumens, such as those found in endoscopes. If a device does require disassembly, reassembly should be easy and designed to prevent user mistakes. Design engineers would benefit from visiting a hospital to see firsthand how a device is used and the debris and contamination that often coats the device after patient exposure.

If packaging is used, it must not only protect the device, but also be compatible with it and enable presentation of the devce into the sterile field.

Devices must be made of materials that can withstand repeated exposure to cleaning and disinfecting chemicals and the sterilization processes required to render reused devices safe for their intended use. Medical devices are differentiated by the degree of risk of infection transmission if they become contaminated. A critical or high-risk device is intended to enter a normally sterile body environment, and must be thoroughly cleaned and sterilized between patient use. A semicritical or intermediate-risk device is intended to come into contact with mucous membranes, and does not ordinarily penetrate body surfaces. It must be thoroughly cleaned and subjected to a high-level disinfection process. A noncritical device comes into contact with skin only and must be thoroughly cleaned and subjected to intermediate or low-level disinfection. Intermediate or high-level disinfection chemicals should be used if there is a concern regarding transmission of pathogens. The most widely used, and the only FDA-approved, high-level disinfection chemicals are gluteraldehyde formulations at concentrations of >2.0% gluteraldehyde with near-neutral or slightly alkaline pH. Worker safety issues must be considered when using these chemicals.

HOSPITAL REPROCESSING

Many differences exist between industrial and hospital sterilization practices. The manufacturer, therefore, must understand the hospital environment and its limitations when contemplating design of a reusable device.

Although hospitals use sterilization methods that are similar to those of manufacturers, such as steam and EtO, the cycles are very different and generally are not validated to industry-accepted sterility assurance levels. The volume, packaging, and composition of hospital loads vary considerably, so no consistent patterns can be established. Hospitals require quick turnaround and often release products before the biological indicator testing is complete. Often, reuse is not documented, and confirmation of device acceptability for use is done by visual examination alone.

Medical device manufacturers typically don't have a lot of experience with cleaning and disinfection technology, and are unfamiliar with the kind of bioburden encountered as a result of patient use. The contamination on a patient-exposed device can include blood, serum, and tissue fragments, which impede the sterilization process by protecting microorganisms from contact with the disinfecting or sterilizing agent.

A 1996 study conducted by M.J. Alfa, PhD, produced alarming evidence that improper cleaning can result in a nonsterile device, even after exposure to all standard hospital sterilization cycles. Effective cleaning becomes the most critical step in the reprocessing cycle, a step manufacturers are not accustomed to evaluating. All of the elements of the reprocess cycle must therefore be understood if the device manufacturer is to design a device for acceptable reprocessing, then validate the reprocessing method and develop appropriate label instructions.

Figure 1. Hospital reprocessing cycle.

The hospital reprocessing cycle consists of several important steps: use, decontamination, cleaning and disinfection, packaging, sterilization, storage, and reuse (see Figure 1).

Devices are typically placed into an enzyme or detergent solution immediately after use to prevent adhesion of bodily fluids and tissue debris. The outside of the device is often wiped to remove gross debris. Once blood or tissue dries on or in a device, all efforts to remove it may be unsuccessful.

Upon receipt of the used devices in the hospital central service department, the appropriate manual or automatic cleaning procedure is performed. Cleaning is affected by water hardness and pH, cleaning-product formulation, temperature, contact time, and cleaning method. Manual cleaning has decreased in popularity over the last 10 years because of the concern over transmission of bloodborne diseases, and is now used only for devices that will not tolerate conditions present in automatic washers and for some delicate microsurgical devices to prevent breakage.

Automatic cleaning can be accomplished with three methods: ultrasonic, washer-disinfector, and washer-sterilizer cleaning. Ultrasonic cleaning is used with items that have uneven surfaces that may trap debris. It may also be used as an initial cleaning step for removal of fine debris. The water bath in ultrasonic cleaners uses tap water at temperatures ranging from 60° to 140°F and an alkaline detergent (pH 8­11). Washer-disinfectors not only clean devices, but also provide intermediate- to high-level disinfection with a hot-water rinse (180°­202°F). Many different manufacturers supply this type of equipment; some systems use highly alkaline detergents (pH 12+) for cleaning with a neutralizing acid rinse, while others use neutral or slightly alkaline detergents relying on thorough coverage and the force of the water spray to produce cleaning. Drying phases incorporated into many mechanical washers can produce temperatures as high as 300°F. Washer-sterilizers are available in two configurations: the flooding type, which are usually small units that immerse the devices in a detergent-and-water solution at 150°F followed by a flash steam cycle; and a tunnel unit in which cleaning is accomplished by rotating spray arms followed by a steam cycle at temperatures of 285°F.

Given these options, the manufacturer must evaluate the following key issues and determine which cleaning methods to require in the labeling information.

Critical reusable devices must be sterilized. Traditional sterilization methods used in hospitals for critical devices are similar to those used by the manufacturer; however, the steam and EtO sterilizers with preprogrammed cycles are specifically designed for hospital use. The chambers are generally smaller than those of industrial sterilizers, and the cycle parameters are preprogrammed to ensure correct selection each time. The cycles have been validated by the manufacturer, but biological testing using specific hospital chamber loading patterns is not performed (specific cycle parameters can be found in the AAMI TIR 12 Annex).

In response to increased restrictions on EtO, some new low-temperature technologies have been developed. Liquid peracetic acid is a popular technology used for flexible endoscopes. Gaseous processes are based on application of peracetic acid or hydrogen peroxide chemistries followed by a plasma phase. These processes are appealing to hospitals because the cycles are short in duration (lasting 1 to 3 hours), occur at low temperatures, and do not produce toxic by-products or residues. Typically, the gas-plasma sterilization process occurs in a deep vacuum. The desired chemical sterilant is introduced into the chamber as a vapor, and after a short diffusion phase, a radio-frequency or microwave field is applied, which produces highly biocidal active species plasma. Although the exact mechanism of action by the gas plasma has not been determined, the ability of the process to sterilize various items has been demonstrated. Because of the ever-increasing popularity of these systems in health-care settings, reusable device manufacturers should consider validating a plasma process and recommending it in the product labeling.

VALIDATING STERILIZATION METHODS

Manufacturers should not only understand hospital sterilization methods, but also validate these methods using actual hospital scenarios. With the standard industrial overkill method of a 6-log inactivation of organisms in a one-half cycle in mind, manufacturers must also add hospital-specific preparation activities to the validation protocol.

The entire reprocessing cycle must be evaluated. As with industrial validation, selection of the worst-case-challenge product and worst-case load begins the process. Hospitals sterilize wrapped or pouched products on carts or in reusable metal containers in small sterilizers, not on pallets in large chambers.

Lumen devices and hinged instruments are generally selected as worst-case challenges because these are the most difficult products to clean and sterilize. A simulated lumen device can be used, which consists of a length of tubing having a diameter equal to the smallest-diameter device with a closed end (this simulates an endoscope).

Contamination of used devices generally consists of bacteria plus protenaceous debris, which adds to the challenge. It is therefore recommended that in addition to seeding devices with biological indicator (BI) strips, direct inoculation of a serum and hard water spore suspension into lumens and hinges should be performed to assess the effectiveness of the entire reprocessing cycle. The devices should then be subjected to the cleaning steps after inoculation before packaging and sterilization is performed.

Using a hospital sterilizer or a small industrial chamber programmed with hospital cycle parameters, the manufacturer should build a typical hospital load and place BI-seeded devices, BI- and serum-inoculated and cleaned devices, and temperature-monitoring sensors throughout the load, and then run a cycle consisting of one-half the routine sterilant exposure time. It is not always possible to minimize all other parameters. The validation load should include the customary hospital self-contained BIs, which provide a readout as quickly as 1 hour after sterilization; universal chemical indicators; and a standard hospital test pack. The standard hospital test pack might consist of a syringe containing a BI strip within the barrel placed between several operating room towels, which is then wrapped twice with standard hospital polyester or muslin wrap. Cellulosic materials cannot be used in some plasma processes because of their absorption of the sterilant.

After exposure, the test devices and BIs should be retrieved and sterility tested. Total inactivation is the acceptable result. If testing validates the proper microbial inactivation, then device sterilization compatibility and possible sterilant residual buildup should be determined. As with any validation, all procedures and tests, as well as results, must be documented.

REUSE OF SINGLE-USE DEVICES

Manufacturers have had long-standing concerns with the reuse of single-use devices, including product functionality, safety, and liability. They often feel that reprocessing a device that is designed and labeled for single use actually creates a new device. The Health Industry Manufacturers Association (HIMA) has adopted the following guiding principles:

FDA has not yet focused on the practice of reuse, and the agency has sent mixed messages about its authority over third-party reprocessors. According to HIMA, however, when a company reprocesses a single-use device, it clearly creates a new device and is therefore subject to applicable FDA requirements, including 510(k) approval and GMP compliance.

FDA is now beginning to work with the Centers for Disease Control and Prevention (CDC) and other agencies to develop more data correlating infection rate to reuse of single-use devices. Most studies reported in the literature so far are small and have questionable methods; the results do not prove a causal relationship.

Until higher-quality data are produced, FDA continues to support the position outlined in its 1987 document, "Reuse of Medical Disposable Devices." According to this document, if a health-care provider chooses to reprocess a device labeled for single use, he or she must ensure the safety and efficacy of the device.

Other countries have recently addressed the issue of reuse more directly. The Medical Devices Agency in the UK issued a bulletin on reuse in early 1995 that states "there may be some circumstances in which carefully controlled reuse may be justified." A report on a national approach to the reuse of single-use devices is expected from the Australian Therapeutic Devices Branch by the year's end. The Canadian Hospital Association released a comprehensive document in late 1996 that includes a discussion of the issues, a method of analysis, and suggested testing protocols.

Although many deplore the practice, the reuse of single-use devices is a reality. Health-care workers, manufacturers, and regulatory officials must institute practices and procedures to ensure that the reused devices are safe, whether or not they are being used as the manufacturers intended.

BIBLIOGRAPHY

AAMI Technical Information Report 12, Designing, Testing and Labeling Reusable Medical Devices for Reprocessing in Health Care Facilities: A Guide for Device Manufacturers, Arlington, VA, AAMI, 1994.

Alfa MJ, "The Effectiveness of Hospital Sterilization," Infect Cont Hosp Epid, 17(92), 1996.

Block SS, Disinfection, Sterilization, and Preservation, 4th ed, Philadelphia, Lea & Febiger, 1991.

Burgess DJ, Reich RR, and Fleming W, "Destination Sterility: A Road Map to Validation," Infect Cont Ster Tech, May 1996.

"Compliance Policy Guide," No. 7124.16, Rockville, MD, FDA, revised September 1987.

Kahan JS, "FDA Regulation of Medical Device Reuse," Med Dev Diag Ind, 17(11): 62­68, 1995.

Labeling Reusable Medical Devices for Reprocessing in Health Care Facilities: FDA Reviewer Guidance, Rockville, MD, FDA, Center for Devices and Radiological Health, Office of Device Evaluation, 1994.

McCormick PJ, "Sterilization Processes Used for Device Reprocessing," The Validation Consultant, 3(8), 1996.

Page BFJ, "Standards and Regulations Supporting Reuse of Medical Devices, The Validation Consultant, 3(8), 1996.

Reichert M, "Cleaning, Disinfecting and Sterilizing Reusable Medical Devices in the Healthcare Setting," presented to the Infection Control Symposium, January 1995.

"Reprocessing Medical Devices," Position Paper No. 1, American Society for Healthcare Central Service Personnel and The International Association of Healthcare Central Service Materiel Management, 1994.

Schultz J, "Cleaning Methods Used in Healthcare Facilities," The Validation Consultant, 3(8), 1996.

Whitborne J, Kuhnert S, and Monnat K, "Validating the Cleaning, Disinfection and Sterilization of Reusable Medical Devices," Med Dev Diag Ind, 16(6): 68­74, 1994.

Anne F. Booth is principal of Booth & Associates (Barrington, IL) and publisher of The Validation Consultant.

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