Sterilization of Medical Devices

Anne Booth

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781351413800
• Edition: 1
• Topic: Medicine
• Subtopic: Forensic Medicine

This book presents vital information on international sterilization standards and guidance on practical application of these standards in the manufacturing process. It covers validation, industrial sterilization methods, emerging sterilization techniques, laboratory testing, manufacturing of sterile devices, and device reuse. Excerpted from The Validator, edited by Anne F. Booth, more than fifty experts share their knowledge of current technologies in easy-to-understand articles that establish methods to ensure compliance. Contents include reviews of ISO sterilization standards, industrial sterilization methods and technologies, and support testing methodologies.

VII

Reuse of Devices

41

Reuse of Devices

Anne F. Booth

Booth Scientific, Inc.
Barrington, Illinois

A significant shift is occurring in the delivery of medical devices to the end user. In the 1980s, the reuse of hemodialyzers began, with 63 percent of dialysis centers reusing devices by 1986. Since that time, cost containment and waste reduction efforts in healthcare facilities have placed additional pressure on medical device manufacturers to accommodate the end user with cost-effective reusable devices. In addition, advances in medical technology have led to the development of new, highly sophisticated and complex instruments and devices that are, in many cases, reusable. Some hospitals are reusing and/or reprocessing single-use devices as well. A survey conducted by Infection Control and Sterilization Technology indicated that 35 percent of hospitals responding to the survey reuse devices, primarily catheters, blades and knives; 43 percent reprocess items, with catheters again being the device mentioned most frequently.

Along with this trend is the development and implementation of new sterilization technologies targeted for the healthcare facility, mainly developed as the result of eliminating the safe 12/88 sterilant mix. These include plasma-based technologies that provide quick turnaround so critical to maintaining low inventory of high-priced medical devices. Even though steam is still the sterilization process of choice, many hospitals must use other processes because many devices require low-temperature processing to maintain material integrity and device function over the expected life of the device.

Who Is Responsible?

Who, then, is responsible for ensuring that every patient receives a sterile, functional device for each procedure? Medical device manufacturers have long followed Food and Drug Administration (FDA) rules in the manufacture of single-use devices by establishing and following GMP procedures. Thus, it should be no surprise that FDA expects the same quality efforts from the manufacturer in the design, testing and labeling of devices for reuse.

All label claims of reuse provided in instructions for the handling, cleaning, disinfection, packaging and sterilization of products in the healthcare facility must be tested and validated. Once sold and in the hands of the end user, however, no regulatory body oversees the use and reuse of devices. Hospitals are not bound by GMP although their reprocessing activities are informally guided by recommended practices of the Association of Operating Room Nurses (AORN), the American Society of Healthcare Central Service Personnel (ASHCSP), the Association for Professionals in Infection Control and Epidemiology (APIC) 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 to coordinate with manufacturers to ensure that the necessary training and resources are available to follow these recommendations.

The AAMI Technical Information Report (TIR) No. 12 was developed jointly by manufacturers and hospital professionals to address mutual concerns and to develop standardized methods based on proven technology. In Chapter 43, Mr. Page discusses this and other standards as well as regulations governing this activity and provides some suggestions on design considerations. What is the bottom line? The FDA places the primary responsibility on the manufacturer to develop and validate methods for the effective reprocessing of its devices.

Understanding Hospital Practices

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

Although hospitals utilize similar sterilization methods, i.e., steam and ethylene oxide (EO), the cycles are very different and generally are not validated to industry-accepted sterility assurance levels (SALs). 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 biological indicator (BI) testing is complete. Often, reuse is not documented, and the confirmation of device acceptability for use is done only by a visual examination.

Medical device manufacturers don’t have a lot of experience with cleaning and disinfection technology due to manufacturing in a GMP environment and are unfamiliar with the kind of bioburden encountered as a result of patient use. The contamination on a patient-exposed device includes blood, serum and tissue fragments that impede the sterilization process by “protecting” microorganisms from contact with the disinfecting or sterilizing agent. Dr. Alfa’s study, detailed in Chapter 45, produced alarming evidence that improper cleaning can result in a nonsterile device, even after exposure to sterilization. All of these elements must be understood if the device manufacturer is to design a device acceptable for reprocessing.

Recommendations for Design, Cleaning and Sterilization

The first element in a comprehensive, reusable device program is adequate design with ease of reprocessing in mind. Hinged joints, small crevices and narrow lumens will all interfere with the ability to clean and sterilize devices adequately. Since devices will be subjected to difficult-to-clean “soils,” the ease with which they can be cleaned is critical to successful sterilization. Engineers would benefit from a visit to the hospital to watch and understand the methods used and see first hand the debris and contamination that often coat a device after patient exposure.

Jan Schultz outlines some of the most widely used hospital cleaning practices in Chapter 46. Use this information to select and validate one or more cleaning methods that must be, of course, repeatable in a healthcare facility. It must be understood that the user is ultimately responsible for choosing the correct cleaning agent, based on the instructions of the manufacturer and any recommendations of the cleaning equipment manufacturer.

In Chapter 48, Dr. McCormick outlines the theory supporting sterilization methods used in hospitals for reprocessing devices. Be aware, however, that hospital steam and EtO cycles are different from those used in industry, so tests utilizing hospital sterilizer parameters are essential. Some of these parameters are listed in Chapter 45 and in Annex B of AAMI TIR No. 12.

Validation of Recommended Methods

Manufacturers should not only understand hospital methods but also validate these methods with in-use hospital scenarios. With the standard industrial overkill method of inactivation of six logs of organisms in a one-half cycle in mind, manufacturers must also add hospital-specific preparation activities to the validation protocol. This can be accomplished by first understanding the entire reprocessing cycle of use—decontamination, cleaning and disinfection, packaging, sterilization, storage and reuse.

As with industrial validation, selection of the worst-case challenge product and worst-case load begin the process. Hospitals sterilize wrapped/pouched products in carts or 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 to clean and sterilize. Contamination on used devices generally consists of bacteria plus proteinaceous debris that adds to the challenge. It is therefore recommended that in addition to seeding devices with BI strips, direct inoculation of a serum/hard water/spore suspension into lumens and hinges is required to assess the effectiveness of the entire reprocessing cycle. These latter devices should be subjected to the entire reprocessing steps after inoculation and before packaging and sterilization is performed. A simulated lumen device consists of a length of tubing with the diameter equal to the smallest diameter device with a closed end (simulates an endoscope).

Using a hospital sterilizer or a small industrial chamber programmed with hospital cycle parameters, build a typical hospital load and place BI-seeded devices, BI/serum inoculated and cleaned devices, as well as temperature-monitoring sensors, if possible, throughout the load and run a cycle consisting of one-half the routine sterilant exposure time. It is not always possible to minimize all other parameters. BIs and devices are retrieved and sterility tested and total inactivation is expected for an 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.

Let’s Examine the Question of Reusing Single–Use Devices

Healthcare facilities face tough choices in the selection of appropriate devices. In Chapters 51 and 52, Ms. Koch and Ms. Reichert, respectively, discuss some of the challenges faced by hospital purchasing groups and the reasons some hospitals consider reusing single-use devices. Reichert emphasizes the need for written procedures based on research showing that the device can be safely reprocessed. Manufacturers have had long-standing concerns with the reuse of single-use devices, however, including product quality, safety and liability. They feel that reprocessing a device that is designed and labeled for single use creates a new device.

The Health Industry Manufacturers Association (HIMA) has adopted a set of guiding principles pertaining to the reuse of single-use devices. These principles are presented in a position paper recently published by HIMA. These are driven by HIMA’s commitment to patient and employee health and safety and are as follows:

• The manufacturer has ...