ISO/IEC Guide 63:1999

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GUIDE 63
Guide to the development and
inclusion of safety aspects in
International Standards for
medical devices
First edition 1999

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ISO/IEC GUIDE 63:1999(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in
liaison with ISO and IEC, also take part in the work.
Guides are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft Guides adopted by the responsible Committee or Group are circulated to national bodies for voting.
Publication as a Guide requires approval by at least 75 % of the national bodies casting a vote.
Health care technology
ISO/IEC Guide 63 was prepared by ISO/IEC Joint Technical Advisory Group 1 (JTAG 1), ,
with the collaboration of ISO/TC 210, Quality management and corresponding general aspects for medical devices.
The draft was agreed by the meeting of JTAG 1 on 20 April 1998.
© ISO/IEC 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office • Case postale 56 • CH-1211 Genève 20 • Switzerland
Printed in Switzerland
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ISO/IEC ISO/IEC GUIDE 63:1999(E)
Introduction
ISO/IEC Guide 51, Guidelines for the inclusion of safety aspects in standards, is the first of a series intended to
provide a harmonized approach to the concept of safety when preparing International Standards. ISO/IEC Guide 51
anticipates the need for sectoral guides such as this Guide 63.
While safety is a key element of medical device standards, there is a need to address performance as well.
Consistent with ISO/IEC Guide 51, additional guidance may be needed for sectors within the broad category of
medical devices. Existing examples are IEC/TR 513, Fundamental aspects of safety standards for medical electrical
equipment and ISO/TR 14283, Implants for Surgery — Fundamental Principles. The above-mentioned documents
were among the sources used for the concepts described in this Guide.
The concept of safety is closely related to safeguarding the integrity of both the patients who are the subjects of
medical care and those persons who are giving the care. As the complexity of medical devices and diagnostics
devices and systems have become more complex, the diligence required to ensure their safety has similarly
increased.
There can be no absolute safety. Even at the highest level of safety, a medical device can only be relatively safe.
Medical practice involves protection of the patient's well-being while applying treatments that have some degree of
inherent risk. It is incumbent on the designers and manufacturers of medical devices to ensure that the devices
used in diagnosis, treatment or alleviation of handicap do not harm or present possibilities of harm to the patient
that are not outweighed by the benefits offered by the device.
As different circumstances warrant different approaches to ensuring safety, it is impossible to provide precise
provisions and recommendations that apply to every case. However, these guidelines, when followed on a judicious
"use when applicable" basis, will help in developing reasonably consistent standards.
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ISO/IEC ISO/IEC GUIDE 63:1999(E)
Guide to the development and inclusion of safety aspects
in International Standards for medical devices
1  Scope
This Guide provides an approach to writing international standards for medical devices that takes into account the
hazards of medical use, the role of standards in managing risk in relation to the medical need for the device and the
use of standards in medical device design, manufacture and regulation.
This Guide will also help those who use medical device standards to understand what such standards are intended
to accomplish. Among such users are:
— users of medical devices;
— hospital administrators;
— personnel involved in the procurement of medical devices;
— regulatory authorities;
— persons responsible for the design and construction of patient care facilities;
— persons responsible for the installation and maintenance of medical devices;
— manufacturers of medical devices;
— persons who assemble systems of medical devices from more than one manufacturer.
This sectoral Guide is intended to be read in conjunction with ISO/IEC Guide 51.
2  References
ISO 14971-1:1998, Medical devices — Risk management — Part 1: Application of risk analysis.
ISO/IEC Directives, Part 2: Drafting and presentation of International Standards, 1996.
ISO/IEC Guides.
Guidelines for the inclusion of safety aspects in standards.
ISO/IEC Guide 51:1990,
3  Terms and definitions
For the purposes of this Guide, the following terms and definitions apply.
3.1
basic safety
freedom from unacceptable risk created by direct physical hazards when medical devices are properly used under
normal or reasonably foreseeable conditions relating for example to mechanical strength, biocompatibility and
sterility
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3.2
harm
physical injury or damage to the health of people either directly or indirectly as a result of damage to property or to
the environment
3.3
hazard
potential source of harm
3.4
medical device
any instrument, apparatus, appliance, material or other article, whether used alone or in combination, including the
software necessary for its proper application intended by the manufacturer to be used for human beings for the
purpose of:
— diagnosis, prevention, monitoring, treatment or alleviation of disease,
— diagnosis, monitoring, treatment, alleviation of or compensation for an injury or handicap,
— investigation, replacement or modification of the anatomy or of a physiological process,
— control of conception,
and which does not achieve its principal intended action in or on the human body by pharmacological,
immunological or metabolic means, but which may be assisted in its function by such means
NOTE 1   Regulatory authorities may use other definitions of the term medical device.
NOTE 2   A medical device may or may not be used under the direct or indirect supervision of a medical professional.
3.5
quality assurance
all the planning and systematic actions to be implemented, and demonstrated as needed, necessary to provide
adequate confidence that an entity will satisfy given requirements for quality
3.6
risk
combination of the probability of occurrence of harm and the severity of that harm
3.7
safety
freedom from unacceptable risk
4  Risk
4.1  Taking a practical view of safety
Safety must be balanced against other demands on the product, process or service. These other demands include
utility, suitability and cost. Since safety is defined as freedom from unacceptable risk, and absolute safety is
unattainable, medical devices may only be considered as either relatively safe or relatively unsafe.
Although society would like all medical devices to be safe and to perform as intended, the reality is that no system is
perfectly reliable and the risk is never zero. Although zero risk is an ideal to pursue, its attainment should not be
expected. The more realistic expectation is to ensure that risks are kept as low as reasonably achievable.
Evaluation of an acceptable level of risk shall take into account the incremental costs of lower risks and the
magnitude of the corresponding benefit provided by the medical device both to the patient and to society.
In evaluating the safety of medical devices, it is also necessary to consider that certain devices, because of their
means of operation or the circumstances of their use, carry with them an inherent risk that cannot be eliminated
without degrading their effectiveness.
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Since technologies and social values are subject to change over time and differences exist in medical and health
practices among cultures, judgement of safety of medical devices and procedures also changes over time and
among countries. In other words, the evaluation of risk is a subjective rather than an objective exercise. These
issues can often be addressed by identifying the specific conditions under which a technical requirement applies.
Requiring devices to include specific features or functions in addition to those critical to safety or to accomplishing
the uses identified by the manufacturer in accompanying documents should be avoided whenever possible.
4.2  Managing risk
The risk management process includes:
a) identifying hazards;
b) estimating their frequency of occurrence;
c) estimating the probability of harm per occurrence;
d) establishing acceptable risk limits;
e) determining means to maintain each risk within the selected limits;
f) balancing between risks and benefits.
The risk analysis process is described more fully in ISO 14971-1.
Standards development should be based on hazard identification, and the process produce standards that
recommend the actions and precautions needed to ensure that the acceptable level of risk is not exceeded.
These considerations should then be taken into account as the standards developer determines the appropriate
requirements to be included in the standard.
5  Hazards
5.1  General
When preparing a safety standard for a medical device, the initial task is to identify the hazards associated with the
use of the device. There are several types of hazard associated with the application of a medical device in the
course of medical treatment.
5.2  Device-related hazards
To a great extent, the possible device-related hazards depend on the nature of the medical device. Since it is not
possible to ensure that a medical device will not fail, the standard should recognize the potential hazards of the
devices as they pertain to the condition and health of the patient and the safety and health of the user. The
preferred result in the event of a failure is failure to a safe mode (fail-safe). Alternatively, when possible or
practicable, the device should give warning prior to failure or at the time of failure. Warnings and alarms are more
easily included on active devices, but are not impossible to include in many inactive devices. Some examples of
device-related hazards are:
a) failure of a device to perform its intended function, e.g. failure of a defibrillator to deliver the proper energy,
mechanical failure of a cardiac valve;
b) incorrect performance of a device, e.g. a defibrillator delivering less than indicated output;
c) for active medical devices, the hazards due to the energies involved in the proper functioning of the device, e.g.
flow of current through an unintended path through the patient or user, excessive or inadequate heating or
cooling of a patient or part of a patient;
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d) for sterile medical devices, infections transmitted by a non-sterile device, e.g. caused by improper sterilization
or failure of a sterile barrier;
e) hazards incidental to the function of the medical devices, e.g. fire resulting from the ignition of flammable
materials in the vicinity of the medical device;
f) hazards arising from the incorrect reading of a device's output, e.g. misinterpretation of the results of an in vitro
diagnostic test;
g) hazards arising from mechanical failure of a medical device or its ancillary equipment, e.g. collapse of a
component of an X-ray table, failure of side-rails on a hospital bed;
h) hazards related to the toxicity of materials used in the device or leached from the device, or the lack of
biocompatibility of the component materials of the device. These hazards may be immediate (occurring soon
after initial use of the device) or long-term (arising only after prolonged exposure to the device);
i) hazards arising from the interconnection of incomptatible devices, e.g. connection of medical and possibly non-
medical devices from different manufacturers.
5.3  Patient-related hazards
Some hazards are specifically related to the patient and the patient environment. Some examples are:
a) the inability of the patient or user to detect the presence of certain potential hazards, such as ionizing or high-
frequency radiation;
b) the absence of norma
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