ATTACHMENT C - AAMI-TIR34 - HEMODISALYSIS WATER TESTING.pdf

Technical Information Report

AAMI TIR34:

2014/(R)2021 Water for the reprocessing of medical devices

Advancing Safety in Health Technology

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AAMI Technical Information Report AAMI TIR34:2014/(R)2021 (Revision of AAMI TIR34:2007)

Water for the reprocessing of medical devices

Approved 4 August 2014 and reaffirmed 12 December 2017 and 29 March 2021 by

AAMI

Abstract: This technical information report (TIR) covers the selection and maintenance of effective water quality suitable for reprocessing medical devices. It provides guidelines for selecting the water quality necessary for the reprocessing of categories of medical devices and addresses water treatment equipment, water distribution and storage, quality control procedures for monitoring water quality, strategies for bacterial control, and environmental and personnel considerations.

Keywords: carbon filters, deionization, disinfection, distillation, pasteurization, reverse osmosis, sediment filters, sterilization, ultrafiltration, water filtration, water quality, water softening, water treatment

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AAMI Technical Information Report

A technical information report (TIR) is a publication of the Association for the Advancement of Medical Instrumentation (AAMI) Standards Board that addresses a particular aspect of medical technology.

Although the material presented in a TIR may need further evaluation by experts, releasing the information is valuable because the industry and the professions have an immediate need for it.

A TIR differs markedly from a standard or recommended practice, and readers should understand the differences between these documents.

Standards and recommended practices are subject to a formal process of committee approval, public review, and resolution of all comments. This process of consensus is supervised by the AAMI Standards Board and, in the case of American National Standards, by the American National Standards Institute.

A TIR is not subject to the same formal approval process as a standard. However, a TIR is approved for distribution by a technical committee and the AAMI Standards Board.

Another difference is that, although both standards and TIRs are periodically reviewed, a standard must be acted on—reaffirmed, revised, or withdrawn—and the action formally approved usually every 5 years but at least every 10 years. For a TIR, AAMI consults with a technical committee about 5 years after the publication date (and periodically thereafter) for guidance on whether the document is still useful—that is, to check that the information is relevant or of historical value. If the information is not useful, the TIR is removed from circulation.

A TIR may be developed because it is more responsive to underlying safety or performance issues than a standard or recommended practice, or because achieving consensus is extremely difficult or unlikely. Unlike a standard, a TIR permits the inclusion of differing viewpoints on technical issues.

CAUTION NOTICE: This AAMI TIR may be revised or withdrawn at any time. Because it addresses a rapidly evolving field or technology, readers are cautioned to ensure that they have also considered information that may be more recent than this document.

All standards, recommended practices, technical information reports, and other types of technical documents developed by AAMI are voluntary, and their application is solely within the discretion and professional judgment of the user of the document. Occasionally, voluntary technical documents are adopted by government regulatory agencies or procurement authorities, in which case the adopting agency is responsible for enforcement of its rules and regulations.

Comments on this technical information report are invited and should be sent to AAMI, Attn: Standards Department, 901 N. Glebe Road, Ste. 300, Arlington, VA 22203.

Published by

AAMI

901 N. Glebe Road, Suite 300 Arlington, VA 22203 www.aami.org

© 2014 by the Association for the Advancement of Medical Instrumentation

All Rights Reserved

Publication, reproduction, photocopying, storage, or transmission, electronically or otherwise, of all or any part of this document without the prior written permission of the Association for the Advancement of Medical Instrumentation is strictly prohibited by law. It is illegal under federal law (17 U.S.C. § 101, et seq.) to make copies of all or any part of this document (whether internally or externally) without the prior written permission of the Association for the Advancement of Medical Instrumentation. Violators risk legal action, including civil and criminal penalties, and damages of $100,000 per offense. For permission regarding the use of all or any part of this document, contact AAMI at 901 N. Glebe Road, Ste. 300, Arlington, VA 22203. Phone: (703) 525-4890; Fax: (703) 525-1067.

Printed in the United States of America

ISBN 978-1-57020-544-6

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Contents Page

Glossary of equivalent standards .............................................................................................................................. v Committee representation ......................................................................................................................................... vii

Foreword ................................................................................................................................................................... viii Introduction

1. Scope

1.1 General

1.2 Inclusions

1.3 Exclusions

2. Definitions and abbreviations

3. The importance of water quality and effective water treatment

3.1 Introduction

3.2 Major impacts of adverse water quality on medical device reprocessing

3.2.1 General considerations

3.2.2 Microbial level in water

3.2.3 Inorganic and organic components of water

3.2.4 Water temperature

3.3 Treatment of water

3.3.1 General considerations

3.3.2 Pretreatment

3.3.3 Principal water treatment processes

3.3.4 Distribution

3.4 Categories of medical devices

3.5 Stages of medical device reprocessing in which water quality is a consideration

4. Categories of water quality for medical device reprocessing

4.1 Introduction

4.2 Two categories of water quality

5. Selection of water quality

5.1 Introduction

5.2 Cleaning

5.2.1 Manual cleaning

5.2.2 Mechanical cleaning by medical washers and medical washer–disinfectors

5.2.3 Automated cleaning by ultrasonic cleaners

5.3 Disinfection and sterilization

5.3.1 General considerations

5.3.2 Medical devices that receive steam sterilization or low-temperature gas sterilization

5.3.3 Medical devices that receive liquid chemical high-level disinfection

5.3.4 Medical devices that receive liquid chemical sterilization

5.3.5 Medical devices that receive pasteurization or thermal disinfection

6 Water treatment systems

6.1 Introduction

6.2 General issues associated with water treatment

6.3 Design of water treatment systems

6.3.1 General considerations

6.3.2 Physical layout of the water purification, distribution, and storage system

7 Monitoring water quality

7.1 Introduction

7.2 Goals of water quality monitoring

7.3 Water characteristics that should be monitored

7.3.1 General considerations

7.3.2 Water temperature

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8 Strategies for bacterial control 9 Personnel considerations

9.1 Introduction

9.2 Device reprocessing personnel

9.3 Water maintenance personnel

9.4 Audits

10 Continuous quality improvement

10.1 Introduction

10.2 Quality process

Annexes

A Water treatment methods

B Monitoring water treatment equipment and processes

C Water storage and distribution

D Strategies for bacterial control E Thermal disinfection

F Water treatment using filtration

G Typical presentation of water quality issues during the reprocessing of medical devices

H Bibliography

Tables 1 Categories and recommended levels of water quality for medical device reprocessing

2 Water quality for reprocessing devices to be sterilized by steam or low-temperature gas

3 Water quality for reprocessing devices to be high-level disinfected 4 Water quality for reprocessing devices to receive liquid chemical sterilization 5 Water quality for reprocessing devices to be pasteurized or thermally disinfected

6 Overview of water quality monitoring

7 Quality monitoring of cleaning, disinfection, and sterilization equipment

A.1 Summary of water treatment methods

A.2 Processes that can remove interfering compounds that might be found in water

B.1 Monitoring water treatment equipment E.1 Holding times in instrument washers G.1 Examples of observed problems during device reprocessing that can be caused by poor water quality

Figures

1 Stages of medical device reprocessing in which water quality is a consideration

2 Example of a recommended general water treatment process for incoming water to produce treated water that is appropriate for use in medical device reprocessing

A.1 Examples of water treatment processes to produce critical and softened water

A.2 Example of a water treatment process

A.3 Example of a water treatment process

A.4 Example of a water treatment process iv © 2014 Association for the Advancement of Medical Instrumentation ■ AAMI TIR34:2014

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Glossary of equivalent standards

International Standards adopted in the United States may include normative references to other International Standards. AAMI maintains a current list of each International Standard that has been adopted by AAMI (and ANSI).

Available on the AAMI website at the address below, this list gives the corresponding U.S. designation and level of equivalency to the International Standard.

www.aami.org/standards/glossary.pdf

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Committee representation

Association for the Advancement of Medical Instrumentation

AAMI Water Quality for Medical Device Reprocessing Working Group

This technical information report (TIR) was developed by the AAMI Water Quality for Medical Device Reprocessing Working Group under the auspices of the AAMI Sterilization Standards Committee. Approval of the TIR does not necessarily mean that all working group members voted for its approval. At the time this TIR was published, the Water Quality for Medical Device Reprocessing Working Group had the following members:

Co-chairs: Jacqueline Daley, Sinai Hospital of Baltimore Emily Mitzel, MS, Nelson Laboratories Inc

Members: James Weldon Baker, AmeriWater Ralph J. Basile, MBA, Healthmark Industries Company Inc Nola Bayes, MBA, Sanford Health Chris Bible, Belimed Inc David J. Brodersen, Covidien Jennifer Burrell, Integrated Medical Systems Harriet Chan-Myers, Johnson & Johnson Nancy Chobin, RN CSPDM, St Barnabas Healthcare System Matthew Dehmler, Bausch & Lomb Inc Stacy DeMoss, NAMSA Mary Ann Drosnock, MS, Olympus America Inc Betty D. Edge, North Shore University Hospital Marcia Ann Frieze, Case Medical Inc Steve N. Goldstine, PhD, Steve Goldstine Consultants Shelley Green, WuXi AppTec Inc Charles Oren Hancock, RAC, H&W Technology LLC Douglas F. Harbrecht, Sterility Assurance LLC Sandra Iverson, Medivators Inc Nupur Jain, Intuitive 0053urgical Inc Nancy E. Kaiser, Steris Corporation Md Sajedul Islam Khan, II, Apollo Hospital Dhaka Carolyn L. Kinsley, LexaMed Ltd Susan G. Klacik, CCSMC FCS ACE, IAHCSMM Colleen Patricia Landers, RN, Timmins & District Hospital Jo Ann Barbara Maltais, PhD, Maltais Consulting Teckla A. Maresca, LPN CSPDM, St Clare's Health System Rodney D. Parker, Stryker Instruments Division Patrick Polito, Moog Medical Devices Linda Slone, RN BSPA CNOR Donald Socha, Jr., Getinge USA Joan M. Spear, MBA RM CMPR, B Braun of America Inc Karen Swanson, Connecticut Childrens Medical Center Sharon Van Wicklin, MSN RN CNOR/CRNFA, Association of Perioperative Registered Nurses Nora E. Wikander, RN,CSPDM, St Josephs Wayne Hospital Kelvin J. Witcher, 3M Healthcare Martha L. Young, Martha L Young, LLC

Alternates: Denise Adams, B Braun of America Inc Mike Cain, Getinge USA Claudia Camp, Stryker Instruments Division Charles Cogdill, Covidien Ramona Conner, RN MSN CNOR, Association of Perioperative Registered Nurses Robert Dumont, Case Medical Inc Gordon M. Ely, WuXi AppTec Inc Brent Geiger, MS RAC, Medivators Inc Stephen M. Kovach, Healthmark Industries Company Inc Chris Lau, LexaMed Ltd Seth Masek, Covidien Gerald E. McDonnell, PhD, Steris Corporation Joelle Pelletier, TSO3 Inc Joy Perry, Moog Medical Devices vi © 2014 Association for the Advancement of Medical Instrumentation ■ AAMI TIR34:2014

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Michelle Pierce, NAMSA Michael Quin, Johnson & Johnson Michael J. Schoene, Bausch & Lomb Inc Grace A. Thornhill, PhD, 3M Healthcare Sara Toole, BS RM, Nelson Laboratories Inc Donna Ungvarsky, MSN MEd RN CNOR, Olympus America Inc Brian Wallace, Intuitive Surgical Inc Jonathan A. Wilder, PhD, H&W Technology LLC

NOTE—Participation by federal agency representatives in the development of this document does not constitute endorsement by the federal government or any of its agencies.

At the time this document was published, the AAMI Sterilization Standards Committee had the following members:

Co-chairs: Victoria M. Hitchins, PhD, FDA/CDRH Michael H. Scholla, Dupont Protection Technologies

Members: Christopher Anderson, Boston Scientific Corporation Trabue D. Bryans, BryKor LLC Nancy Chobin, RN CSPDM, St Barnabas Healthcare System Charles Cogdill, Covidien Ramona Conner, RN MSN CNOR, Association of Perioperative Registered Nurses Jacqueline Daley, Sinai Hospital of Baltimore Kimbrell Darnell, CR Bard Lisa Foster, Medpoint LLC Joel R. Gorski, PhD, NAMSA Joyce M. Hansen, Johnson & Johnson Douglas F. Harbrecht, Sterility Assurance LLC Deborah A. Havlik, Hospira Worldwide Inc Susan G. Klacik, CCSMC FCS ACE, IAHCSMM Byron J. Lambert, PhD, Abbott Laboratories Colleen Patricia Landers, RN, Timmins & District Hospital Reynaldo Lopez, Cardinal Health (MP&S) Jeffrey Martin, Alcon Laboratories Inc Patrick J. McCormick, PhD, Bausch & Lomb Inc Gerald E. McDonnell, PhD, Steris Corporation Janet M. Prust, 3M Healthcare Nancy Rakiewicz, Moog Medical Devices Mark Seybold, Baxter Healthcare Corporation Andrew Sharavara, PhD, Propper Manufacturing Co Inc Mark N. Smith, Getinge USA James Sidney Wiggs, BSN CRCST, Legacy Health System Martell Kress Winters, BS SM, Nelson Laboratories Inc William E. Young William T. Young, Sterigenics International

Alternates: Lloyd Brown, Covidien Peter A. Burke, PhD, Steris Corporation Dave Dion, Cardinal Health (MP&S) Ken Eddington, NAMSA Gordon M. Ely, WuXi AppTec Inc Thomas J. Frazar, Johnson & Johnson Martha M. Kadas, Sterigenics International Jim Kaiser, Bausch & Lomb Inc Natalie Lind, IAHCSMM Ralph Makinen, Boston Scientific Corporation Mary S. Mayo, CR Bard David Ford McGoldrick, BS, Abbott Laboratories Jerry R. Nelson, PhD, Nelson Laboratories Inc Patrick Polito, Moog Medical Devices Karen Polkinghorne, Dupont Protection Technologies Mike Sadowski, Baxter Healthcare Corporation Craig A. Wallace, 3M Healthcare

NOTE—Participation by federal agency representatives in the development of this document does not constitute endorsement by the federal government or any of its agencies.

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Foreword

This technical information report was developed by the AAMI Water Quality for Medical Device Reprocessing Working Group under the auspices of the AAMI Sterilization Standards Committee. The objective of this TIR is to provide guidelines to personnel involved in medical device reprocessing on the quality of water that should be used in various stages of medical device reprocessing. It is also intended to provide guidelines to water service maintenance personnel on establishing and monitoring water treatment systems. This second edition has been changed to reflect two water categories instead of the four previously specified. There are also many updates and organizational enhancements.

The concepts incorporated in this TIR should not be considered inflexible or static. The recommendations presented here will be reviewed and updated periodically to reflect new information and technical developments regarding water quality and treatment in medical device reprocessing.

Suggestions for improving this TIR are invited. Comments and suggested revisions should be sent to Technical Programs, AAMI, 4301 N. Fairfax Dr., Ste. 301, Arlington, VA 22203-1633.

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Introduction

Water quality is an important consideration in all stages of medical device reprocessing. Ensuring adequate water quality in device reprocessing requires collaboration between the personnel who reprocess medical devices and the personnel who establish and maintain the water treatment system. Because the needs of these two groups are distinct, this technical information report (TIR) contains:

a) sections in the main text that provide guidance for personnel involved in medical device reprocessing on the selection of the recommended water quality for each stage of medical device reprocessing for each category of medical device; and

b) annexes that provide technical information to water maintenance personnel (i.e., personnel who are involved in water treatment and distribution in the facility) to guide them in setting up and monitoring water treatment systems.

Water can be treated by a variety of methods that yield different levels of water quality. In general, as the chemical quality of water improves, its microbial content could increase unless the system is closely monitored to prevent microbial overgrowth. Gram-negative bacteria and nontuberculous mycobacteria can grow in any type of water, including tap, softened, deionized (DI), reverse osmosis (RO) treated, and distilled water. The rate of growth and the microbial levels attained are a function of the amount of organic contaminants in the water. The importance of monitoring water quality to prevent problems with microbial overgrowth cannot be overemphasized.

This TIR defines two levels of water quality suitable for medical device reprocessing, and it describes the water treatment processes that can be used to obtain the correct water quality. To provide optimal water for medical device reprocessing, reprocessing personnel and water maintenance personnel should collaborate with administrative personnel to implement the following procedures:

Step Procedure What to Do Who is Responsible 1 Assessment of water quality The tap water from the public utility source should be analyzed by an accredited facility with expertise in water quality to determine whether the water requires treatment and, if so, what type of treatment. This analysis should take into account seasonal variations in water quality.

Water maintenance personnel

2 Implementation of water treatment process

On the basis of the assessment in Step 1 and in consultation with an accredited facility with expertise in water quality, personnel should ensure that treatment processes are implemented to provide the type of water quality needed for the medical device reprocessing needs of the facility.

Water maintenance personnel in conjunction with device reprocessing personnel

3 Assurance of proper water quality for the various stages in medical device reprocessing

Medical device reprocessing areas should be audited to determine whether water of the correct quality is being used for the devices being reprocessed in each area. If not, the water treatment should be modified as necessary.

Device reprocessing personnel in conjunction with health care technology management personnel

4 Ongoing monitoring of water quality

Where applicable, monitoring procedures should be established to ensure that the treated water is of adequate quality for medical device reprocessing. Water maintenance personnel and device reprocessing personnel should communicate effectively to ensure that action is taken when inadequate water quality is detected.

Water maintenance personnel in conjunction with device reprocessing personnel

This TIR was developed using information on the reprocessing of medical devices labeled for reuse. There might be regulatory requirements or other issues associated with reprocessing single-use devices that were not considered in developing this TIR (see www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/ReprocessingofSingle- UseDevices/default.htm).

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AAMI Technical Information Report AAMI TIR34:2014/(R)2021

Water for the reprocessing of medical devices

1. Scope

1.1 General

This TIR addresses how to determine the water quality needs for reprocessing various categories of medical devices at various stages of reprocessing and how to assess, generate, monitor, and maintain water meeting those requirements.

1.2 Inclusions

This TIR covers the quality of the water used to clean, rinse, disinfect, and sterilize medical devices. It defines water types on the basis of hardness, pH, microorganism levels, endotoxin levels, and other characteristics. The following specific topics are covered:

a) Importance of water quality and effective water treatment

b) Categories of water quality for medical device reprocessing

c) Selection of water quality

d) Water treatment systems

e) Monitoring of water quality

f) Strategies for microorganism control

g) Personnel considerations

h) Continuous quality improvement

i) Troubleshooting water quality issues

This TIR also provides definitions of terms and a bibliography. The annexes contain technical details pertaining to water treatment and monitoring for the benefit of water maintenance personnel.

1.3 Exclusions

This TIR does not cover the water requirements for hemodialysis applications. See ANSI/AAMI/ISO 13959, ANSI/AAMI/ISO 11663, and ANSI/AAMI RD47.

This TIR does not address water treatment performed within medical washers, washer–disinfectors, or automated endoscope reprocessors (AERs); it covers only the water coming into such equipment. The internal filtering or other additional treatment performed within a medical washer, washer–disinfector, or AER is the responsibility of the equipment manufacturer. However, it is in the best interest of reprocessing personnel to be informed of the internal water treatment apparatus and of the equipment manufacturer to take into account the water quality recommendations of this document. See the ANSI/AAMI and ISO 15883 series of documents.

2. Definitions and abbreviations

For the purpose of this TIR, the following terms and definitions apply.

2.1 anion: Negatively charged atom or molecule.

2.2 ATP assessment: Method using adenosine triphosphate (ATP) to indirectly measure viable microbial load.

2.3 automated endoscope reprocessor (AER): Machine intended to disinfect or sterilize loads containing endoscopes.

NOTE—Some AERs have provision for reprocessing accessories.

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2.4 bacterial endotoxins test (BET): Assay for measuring endotoxins by combining a liquid test sample with Limulus amebocyte lysate (LAL) reagent and measuring the resulting proportional reaction by visual, turbidimetric, chromogenic, or other validated means of detection.

2.5 bioburden: Population of viable microorganisms on or in product and/or sterile barrier system.

NOTE—When measured, bioburden is expressed as the total count of bacterial and fungal colony-forming units (cfus) per single item.

2.6 biofilm: An accumulated biomass of bacteria and extracellular material that is tightly adhered to a surface and cannot be removed easily (Donlan, 2002).

NOTE 1—The biomass may consist of multiple bacterial species, yeast species, or both.

NOTE 2—Some microscopic organisms have the ability, when growing in water or water solutions or in vivo (e.g., the bloodstream), to adhere to a surface and then exude over themselves a polysaccharide matrix. The matrix contains cells, living and dead, as well as polysaccharide (sometimes referred to as glycocalyx) and prevents antimicrobial agents, such as sterilants, disinfectants, and antibiotics, from reaching the microbial cells.

2.7 bladder tank: Pressurized tank that has an internal bladder, is part of the water path, and maintains pressure and flow during peak use times.

2.8 cation: Positively charged atom or molecule.

2.9 chemical sterilization: Validated process that uses a chemical agent and is designed to render a product free of viable microorganisms.

2.10 chloramines: Compounds formed by the reaction of aqueous chlorine with ammonia.

2.11 chlorine, combined: Chlorine that is chemically combined, as in the case of chloramine compounds.

NOTE—There is no direct test for measuring combined chlorine, but it can be measured indirectly by measuring both total and free chlorine and calculating the difference.

2.12 chlorine, free: Concentration of residual chlorine in water that is present as dissolved gas (Cl2), hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-).

NOTE—The three forms of free chlorine exist together in equilibrium. Their relative proportions are determined by the pH and temperature of the water.

2.13 cleaning: Removal of contamination from an item to the extent necessary for further reprocessing or for the intended use.

NOTE—In health care facilities, cleaning consists of the removal, usually with detergent and water, of adherent soil (e.g., blood, protein substances, and other debris) from the surfaces, crevices, serrations, joints, and lumens of instruments, devices, and equipment by a manual or mechanical (automated) process that prepares the items for safe handling or further decontamination.

2.14 CLSI: Clinical and Laboratory Standards Institute.

2.15 conductivity, water: Measure of the concentration of ions in solution.

NOTE—Conductivity is measured by a conductivity meter and described in microsiemens/centimeter (cm).

2.16 critical devices: Medical devices that are introduced into or have contact with the bloodstream or normally sterile areas of the body. Examples include, but are not limited to, implants and surgical instruments.

2.17 cross-flow filtration: Process in which viable or nonviable particles are removed from liquids or gases by passage through a porous material, with the filtered particles flowing in one direction and the filtrate flowing in the opposite direction.

2.18 deadleg: With respect to water distribution systems, piping that is more than six times as long as it is wide and that does not have constant water flow.

2.19 decontamination: According to the Occupational Safety and Health Administration (OSHA), “the use of physical or chemical means to remove, inactivate, or destroy bloodborne pathogens on a surface or item to the point where they are no longer capable of transmitting infectious particles and the surface or item is rendered safe for handling, use, or disposal” (29 CFR 1910.1030).

NOTE—The term is generally used in health care facilities to refer to all pathogenic organisms, not just those transmitted by blood.

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2.20 deionization (DI): Water treatment process that uses specially manufactured ion-exchange resin to remove ionized salts from the water.

NOTE—DI typically does not remove organics, viruses, or bacteria, except through “accidental” trapping in the resin. When DI is used, it is advisable to follow the deionizer with a bacterial filter to ensure that the treated water does not contain high levels of bacteria. See A.2.7.

2.21 depth filter: Filter that consists of mats of fibers and that generally has a broad pore-size distribution and high particle-holding capacity.

NOTE—Depth filters are often used as prefilters to remove large particles and to extend the service life of subsequent filters.

2.22 disinfection: Reduction of the number of viable microorganisms on a product to a level previously specified as appropriate for its intended further handling or use.

NOTE—Disinfection destroys most recognized pathogenic microorganisms but not necessarily all microbial forms, such as bacterial spores. Disinfection processes do not ensure the margin of safety associated with sterilization processes.

2.23 distillation: Water treatment process that uses phase change to purify water.

NOTE—For purposes of this TIR, distilled water is considered to be water generated from a properly maintained still on-site, not bottled water labeled as distilled.

2.24 empty bed contact time (EBCT): Measure of how much contact occurs between particles (e.g., activated carbon) and water as the water flows through a bed of the particles.

NOTE—EBCT in minutes (min) is calculated from the following equation:

EBCT = (7.48 x V)/Q

Where:

V is the volume in cubic feet (ft3) of particles in the bed, and

Q is the flow rate (gallons/min) of water through the bed.

2.25 endotoxin: High-molecular-weight complex that is associated with the cell wall of Gram-negative bacteria, is pyrogenic in humans and specifically interacts with Limulus amebocyte lysate (LAL). See also bacterial endotoxins test (BET) and pyrogen.

2.26 endotoxin unit (EU): Standard unit of measure for endotoxin activity initially established relative to the activity contained in 0.2 nanograms of the U.S. Reference Standard Endotoxin Lot EC-2 (United States Pharmacopeia [USP] standard reference material).

NOTE—FDA’s reference endotoxin EC-6, USP Lot G, and the World Health Organization’s primary international endotoxin standard (IS) are sublots of the same endotoxin preparation, making the EU and IU (International Unit) equal (Poole, et al., 1997).

2.27 EPA: U.S. Environmental Protection Agency.

2.28 FDA: U.S. Food and Drug Administration.

2.29 green sand: Manganese-containing zeolite used to remove soluble iron and manganese from water.

NOTE—The manganic ion form in the zeolite oxidizes ferrous and manganous ions in water to their insoluble ferric and manganic forms. The resulting manganous ion in the zeolite can be regenerated to the manganic ion form with potassium permanganate.

2.30 hardness, water: Concentration of calcium and magnesium ions in water, expressed as parts per million (ppm) or milligrams per liter (mg/L) of calcium carbonate (CaCO3) equivalents.

NOTE—Soft water is 0 to 60 ppm CaCO3, moderately hard water is 60 to 120 ppm, hard water is 120 to 180 ppm, and very hard water is more than 180 ppm.

2.31 heterotrophic plate count (HPC): Procedure that estimates the number of viable bacteria that use organic molecules as their principal energy source. It can be used to determine the efficiency of a water treatment process and the quality of treated water.

NOTE—Three different methods, using three different types of media, can be used to perform a heterotrophic plate count: spread plate, pour plate, and membrane filtration.

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2.32 high-level disinfectant (HLD): Liquid chemical sterilant (LCS) used for a shorter exposure time than required for sterilization, under otherwise identical conditions.

2.33 high-level disinfection: Complete elimination of all microorganisms in or on an instrument, except for small numbers of bacterial spores (CDC 2008)

NOTE—For a process that can be used for both chemical sterilization and high-level disinfection, the contact time for high-level disinfection is shorter than that necessary for sterilization, under otherwise identical conditions.

2.34 hydrophobic: Not readily absorbing water; insoluble in water.

2.35 inorganic solutes: Compounds (e.g., salts) that do not contain organic carbon and that are dissolved in a liquid.

2.36 Limulus amebocyte lysate (LAL): Reagent made by lysing amebocytes of the horseshoe crab, Limulus polyphemus, and used to detect and quantify endotoxin.

2.37 lipopolysaccharide (LPS): Gram-negative bacterial cell wall component typically composed of lipid A, a core polysaccharide, and an O-side chain. See also endotoxin.

2.38 liquid chemical sterilant (LCS): Solution of a chemical that has been validated to provide microbial kill adequate to obtain FDA clearance for a sterilization label claim.

2.39 low-level disinfection: Process that kills most vegetative bacteria, some viruses, and some fungi, but not mycobacteria or bacterial spores.

2.40 microfilter: Filter designed to remove particles in the range of 0.1 to 3 microns in diameter.

2.41 microorganism: Entity of microscopic size, encompassing bacteria, fungi, protozoa, and viruses.

NOTE—A specific standard might not require demonstration of the effectiveness of the sterilization process in inactivating all types of microorganisms, identified in the definition above, for validation and/or routine control of the sterilization process.

2.42 noncritical devices: Medical devices that contact only intact patient skin. Examples include bedpans, reusable anesthesia masks, and blood pressure cuffs.

2.43 nonpyrogenic: Term used to describe a health care product that does not induce a fever.

NOTE—Nonpyrogenic may also be used to describe and label health care products that contain endotoxin levels less than specified limits.

2.44 nonpyrogenic water: Water that does not contain endotoxin exceeding a specified endotoxin limit.

2.45 pasteurization: Disinfection process that uses hot water at temperatures of 65°C to 77°C (150°F to 170°F) for a contact time of at least 30 min.

2.46 pH level: Number denoting alkalinity or acidity.

NOTE—The pH scale is logarithmic and runs from 0 to 14; the neutral point is 7. Numbers below 7.0 indicate acidity, and those above 7.0 indicate alkalinity.

2.47 point-of-use (POU) system: Water treatment system in which purification (usually filtration) takes place just before a single water supply outlet.

NOTE—Examples of a POU system are a filter in the line leading to the faucet (such as a filter under a kitchen sink) and a filter attached to the faucet (such as a screw-on tap filter).

2.48 potable water: Water that has been treated and delivered in a manner so that it meets EPA guidelines as suitable for drinking.

2.49 precleaning: Initial stage in reprocessing in which water (or detergent solution) is used to rinse or soak medical devices so that gross levels of any secretions or tissues are removed from patient-used medical devices or other instruments before a more thorough cleaning process is undertaken.

2.50 pyrogen: Fever-producing substance. Pyrogens are most often lipopolysaccharides from Gram-negative bacteria. See also endotoxin.

NOTE—Pyrogens can be classified into two groups: microbial (e.g., bacteria, fungi, viruses) and nonmicrobial (e.g., drugs, device materials, steroids, plasma fractions).

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2.51 reprocess: To prepare a device, instrument, or piece of equipment for reuse by any or a combination of the following processes: precleaning, cleaning, disinfection, sterilization, and rinsing at appropriate stages.

2.52 resistivity: Ability of water to resist the flow of electricity; a measure of the resistance of water and the inverse of conductivity.

NOTE—Resistivity is measured by a resistance monitor and described in megohms-cm (MΏ-cm).

2.53 reverse osmosis (RO): Membrane separation process for purifying water that is based on molecular sieving and ionic rejection and that is effective in removing ions as well as dissolved organic contaminants with molecular weights above 100.

2.54 rinsing: Process of flushing with fluid (usually tap water) the exterior or interior of any lumens of a medical device to remove organic and inorganic material at various stages in medical device reprocessing.

2.55 semicritical devices: Medical devices that contact intact mucous membranes or nonintact skin but do not ordinarily penetrate the blood barrier or otherwise enter normally sterile areas of the body. Examples include, but are not limited to, gastrointestinal endoscopes and respiratory therapy equipment.

2.56 softening: Technique that removes ions that cause water to be hard (usually calcium and magnesium, but iron ions may also be removed by softening).

2.57 sterilant or sterilizing agent: Physical or chemical entity, or combination of entities, that has sufficient microbicidal activity to achieve sterility under defined conditions.

2.58 sterile: Free from viable microorganisms.

NOTE—In practice, no such absolute statement regarding the absence of microorganisms can be proven. See sterilization.

2.59 sterilization: Validated process used to render a product free from viable microorganisms.

NOTE—In a sterilization process, the nature of microbiological inactivation is exponential and, thus, the survival of a microorganism on an individual item can be expressed in terms of probability. While this probability can be reduced to a very low number, it can never be reduced to zero.

2.60 sterilization process: Series of actions or operations needed to achieve the specified requirements for sterility.

NOTE—This series of actions includes pretreatment of product (if necessary), exposure under defined conditions to the sterilization agent, and any necessary post-treatment. The sterilizing process does not include any cleaning, disinfection, or packaging operations that precede sterilization.

2.61 storage tank: Tank in which water is stored for future use, typically at the user’s facility.

NOTE—Because of the potential for bacterial growth and biofilm formation, the use of storage tanks is discouraged.

2.62 submicron filter: Mechanical filtration process that has the capacity to retain particles or organisms that are less than 1 micrometer (µm) in diameter.

2.63 thermal disinfection: Disinfection process that uses hot water at adequate temperatures (higher than 60°C) to kill residual microorganisms.

NOTE—The efficacy of microbial kill depends on the temperature and exposure time. For a more detailed discussion, see Annex E.

2.64 total dissolved solids (TDS): Sum of all ions in a solution, often approximated by means of electrical conductivity or resistivity measurements.

NOTE—TDS measurements are commonly used to assess the performance of water treatment systems. TDS values are often expressed in terms of CaCO3 or NaCl equivalents (ppm).

2.65 total organic carbon (TOC): Measure of both natural and synthetic organic substances that are residual from natural plant and animal decomposition (ASTM D5196-06).

2.66 ultrafilter: Membrane filter with a pore size in the range 0.001 to 0.05 μm.

NOTE—The performance of an ultrafilter is usually rated in terms of a nominal molecular weight cut-off (MWCO), which is defined as the smallest molecular weight species for which the filter membrane has more than 90 % rejection. Ultrafilters with a nominal MWCO of 20,000 or less are generally adequate for endotoxin removal. Ultrafilters are not commonly used to remove particulates.

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2.67 validation: Documented procedure for obtaining, recording, and interpreting the results required to establish that a process will consistently yield product complying with predetermined specifications.

2.68 water purity: Indication of the extent to which impurities (e.g., dissolved organic and inorganic solids and microbial contaminants, ionic, and chemical) have been removed.

2.69 water quality: Descriptor of the levels of various impurities present in water.

NOTE—For example, tap water meets defined water quality standards that ensure that the levels of inorganic chemicals, microorganisms, and radionuclides are within levels that do not pose a risk to the public when ingested (Benner, 2004). For medical device reprocessing, the water quality needed at various stages in the process varies; for example, initial rinsing with tap water is recommended, but final rinsing of cleaned medical devices might require treated water that meets more stringent criteria for ions, microorganisms, organics, and dissolved solutes.

2.70 water treatment system: Collection of water purification devices and associated piping, pumps, valves, and gauges that together produce purified water of a specified quality and deliver it to the point of use.

2.71 wound filter: Filter consisting of two layers of membrane welded together, with one end inserted into a hollow tube. The membranes are wrapped around the tube in a spiral. The layers are arranged and adhered along the lengthwise and widthwise edges so that, in use, unfiltered fluid passing through one spiral surface of the filter unit, into one spacer layer, should pass through a filter layer before passing out of the construction through the opposing spiral-end surface. Wound filters are typically used in reverse osmosis and ultrafiltration.

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3. The importance of water quality and effective water treatment

3.1 Introduction

The overall goals of water treatment in medical device reprocessing are to prolong the life of medical instrumentation, to ensure effectively functioning instrumentation, and, more importantly, to help minimize the risk of adverse patient outcomes arising from contaminated medical devices. This section of the TIR is intended to help users understand the major considerations associated with the quality of water used in medical device reprocessing in health care facilities and the general principles of water treatment.

3.2 Major impacts of adverse water quality on medical device reprocessing

3.2.1 General considerations

The primary objective of medical device reprocessing is to ensure that a device is safe for patient use and does not cause an adverse event in the patient. Adverse patient events to which inadequate water quality can contribute include the following:

a) Device malfunction during a patient procedure (e.g., corrosion of a surgical instrument because of salt or other water deposits could result in breakage of the device inside the patient when stress is applied to the device; mechanical movement of the device could be obstructed by residual debris inside the mechanism because of inadequate cleaning stemming from inactivation of the detergent by water of improper quality)

b) Toxic effects and tissue irritation resulting from residuals on a device or implant that was reprocessed using water of inadequate quality (e.g., pyrogenic reactions could occur as a result of high levels of endotoxin or other pyrogenic agents left as residuals from water that contained high microbial levels; residual salts from water used for the final rinse could be converted by ethylene oxide [EO] to toxic residues)

c) Patient infection resulting from the use of contaminated devices (e.g., salt or organic deposits from the water used in reprocessing could inactivate the disinfectant or sterilant or could protect microorganisms from the disinfection or sterilization process; a disinfected or sterilized device could transmit an infection if rinsed with water containing unacceptable levels of microorganisms) (see Table 1)

d) Ineffective cleaning/disinfection because of chemical integration with water contaminants. Water contaminants can bind with the detergent surfaces, preventing them from dispersing soils.

e) Noncondensable gases (NCGs), defined as gases that cannot be liquified by compression under the conditions of temperature and pressure used during the sterilization process. They can be simplistically described as air in a steam supply. Low levels of NCGs contained in the steam supply to sterilizers can markedly affect the performance of the sterilizer and the efficacy of the process and lead to inconsistencies in the performance of the sterilizer and in Bowie-Dick test results.

It is important that personnel who reprocess medical devices or use them in patient procedures understand the water quality issues that can contribute to adverse patient events and be aware of some of the gross indicators that suggest that there could be problems with the water quality. Monitoring water quality is a prospective process meant to confirm that control strategies are working properly. Monitoring is not a process to prevent biofilm development but rather to indicate when control strategies might require review or remedial action. Inadequate water quality could contribute to residue left on a scope (e.g., film on a scope that adversely affects lens optics).

In the preparation of water for use in medical device reprocessing, two general characteristics need to be considered:

the microbial level in water (3.2.2) and the inorganic and organic components of water (3.2.3).

3.2.2 Microbial level in water

The water used at each stage of reprocessing should not increase the bioburden of the devices being processed.

Water entering the facility from the public utility is usually chlorinated to prevent microbial replication. Even in chlorinated water, however, the level of microorganisms depends on the effectiveness of the municipal treatment process and on the state of the distribution system. (For example, cleaning of the city distribution system often leads to “brown water” as a result of dislodging biofilm within the system. The microbial levels in tap water at such times can be considerably higher than when cleaning is not being performed.) In addition, chlorinated water might contain other inorganic components that will damage medical devices during reprocessing, thereby necessitating water treatment, such as DI, to remove these components. Such treatment will also remove the chlorine; consequently, any microorganisms present will have a significantly greater ability to replicate. Alternative water treatment processes, such as RO, will remove microorganisms as well as inorganic components, thereby reducing the microbial load in the water. However, the RO distribution network could become contaminated with microorganisms and subsequently develop biofilm on the inner surfaces of the piping; in this case, the water will still have unacceptable microbial levels when it is used in medical device reprocessing despite having been properly treated initially.

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Because of these considerations, it is necessary to assess the microbial level of water used for device reprocessing in the facility to ensure that it is acceptable. It is necessary to monitor bacterial levels in tap water, softened water, and deionized water only when systems are installed, modified, or repaired or if problems are identified (see Table 1 and Table 6). Once the microbial level is at an acceptable level (i.e., the level is < 100 colony-forming units per milliliter [cfus/mL]), then monitoring is no longer required. However, it is necessary to monitor microbial levels in “Critical Water” (see 4.2) at intervals that should conform to the recommendations of Table 1 and Table 6. Rapidly addressing unacceptable microbial levels in the water distribution system is critical to keeping biofilm to a minimum.

The risk of adverse patient events associated with the number of microorganisms in the water depends on the type of device and its intended use. The risk is low for devices that will contact only intact tissue. The risk is higher for devices that contact the patient’s bloodstream or other sterile body sites. A report documented Pseudomonas aeruginosa infections associated with the use of transrectal, ultrasound-guided transducer assemblies (CDC, 2006).

As a result of this report, FDA issued a public health notification stating that these medical devices are critical and should be sterilized unless there are parts that cannot withstand the rigors of sterilization, in which case high-level disinfection may be used (FDA, 2006a). In addition, FDA recommended that sterile water—not tap water—should always be used to rinse such devices after high-level disinfection.

Microbial level is measured as the number of cfus per mL of water.

3.2.3 Inorganic and organic components of water

3.2.3.1 General considerations

A number of water characteristics contribute to unacceptable organic and inorganic levels: bacterial endotoxin, total organic carbon (TOC), pH, water hardness, and ionic contaminants.