INTERNATIONAL ISO
STANDARD 21917
First edition
Anaesthetic and respiratory
equipment — Voice prostheses
PROOF/ÉPREUVE
Reference number
ISO 21917:2021(E)
ISO 2021
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ISO 21917:2021(E)
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© ISO 2021

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ISO 21917:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General requirements ..................................................................................................................................................................................... 2

5 Materials ....................................................................................................................................................................................................................... 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Biological safety of gas pathways ............................................................................................................................................ 2

6 Design requirements ........................................................................................................................................................................................ 2

6.1 General requirements ....................................................................................................................................................................... 2

6.2 Valve leakage ........................................................................................................................................................................................... 2

6.3 Valve opening pressure ................................................................................................................................................................. 3

6.4 Characteristic curves ...................................................................................................................................................................... 3

7 Requirements for voice prostheses supplied sterile ........................................................................................................ 3

8 Packaging of voice prostheses supplied sterile ...................................................................................................................... 3

9 Information supplied by the manufacturer ............................................................................................................................. 3

9.1 General requirements ....................................................................................................................................................................... 3

9.2 Marking ......................................................................................................................................................................................................... 3

9.3 Instructions for use ............................................................................................................................................................................. 4

Annex A (informative) Rationale .............................................................................................................................................................................. 5

Annex B (normative) Test methods ....................................................................................................................................................................... 6

© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii
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ISO 21917:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 121, Anaesthetic and respiratory

equipment, Subcommittee SC 2, Airways and related equipment and is written following the format of

ISO 18190 General standard for airways and related equipment. The requirements in this device-specific

standard take precedence over any conflicting requirements in the general standard.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 21917:2021(E)
Introduction

Voice prostheses are used to restore voice in patients after total laryngectomy. They are placed into

a surgically created tracheoesophageal puncture (TEP). The placement can be performed during

the laryngectomy (primary placement), later after healing as an endoscopic procedure (secondary

placement) or in order to replace a voice prosthesis (replacement procedure). There exist different

prosthesis specific placement tools to insert a voice prosthesis into the TEP. Placement of the voice

prosthesis can be performed via the tracheostoma (anterograde), via the mouth (retrograde) and via the

surgical wound (intraoperative).
Voice prostheses have three essential functions:
— they prevent spontaneous closure of the TEP;
— they allow airflow into the pharynx for the creation of speech;
— they seal the TEP during swallowing.

Safe retention of the voice prosthesis is achieved by the oesophageal and tracheal flanges. The

oesophageal flange is placed into the oesophagus, the tracheal flange is placed in the trachea. In order

to prevent leakage of food and saliva into the trachea voice prostheses have a one-way valve that opens

in the direction of the oesophagus.

Voice prostheses have a limited service life and have to be replaced if they start leaking or if they are

overgrown with a biofilm.
There are two groups of voice prostheses:
— indwelling voice prostheses and
— non-indwelling voice prostheses.

Indwelling voice prostheses are placed by a professional (e.g., speech-language pathologist, physician)

and left in the TEP until they fail. They are then replaced.

Non-indwelling voice prostheses are replaced by the patient himself after a certain training period.

The following three most common test methods have been included to determine:

a) Leakage, which provides information about the basic one-way function of the voice prosthesis valve.

b) the valve opening pressure, which evaluates the ability of the valve to withstand phenomena that

can cause leaking/aspiration during swallowing and inspiration.

c) characteristic curve, which allows an assessment of the air flow resistance of the voice prosthesis

during speech.

Annex A contains rationale statements for some of the requirements of this document and

recommendations that have been incorporated into this document. It is considered that knowledge of

the reasons for the requirements and recommendations will not only facilitate the proper application of

this document but will expedite any subsequent revisions.
Throughout this document the following print types are used:
— Requirements and definitions: roman type;

— Informative material appearing outside of tables, such as notes, examples and references: smaller

type;
— Terms defined in clause 3: italic type.
© ISO 2021 – All rights reserved PROOF/ÉPREUVE v
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INTERNATIONAL STANDARD ISO 21917:2021(E)
Anaesthetic and respiratory equipment — Voice
prostheses
1 Scope

This document specifies performance requirements for voice prostheses including requirements for

marking, packaging and information to be provided by the manufacturer as well as test methods for the

evaluation of physical characteristics of voice prostheses.
NOTE There is guidance or rationale for this list item contained in A.2.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 11607-1, Packaging for terminally sterilized medical devices — Part 1: Requirements for materials,

sterile barrier systems and packaging systems

ISO 18190:2016, Anaesthetic and respiratory equipment — General requirements for airways and related

equipment

ISO 18562-1, Biocompatibility evaluation of breathing gas pathways in healthcare applications — Part 1:

Evaluation and testing within a risk management process
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 18190 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
characteristic curve

curve that defines the relationship between pressure and flow across the voice prosthesis

3.2
flange dimension
main dimensions of the tracheal and oesophageal flanges

EXAMPLE For a round flange, the outside diameter; for an oval flange, the major and minor dimensions.

3.3
in-situ service life
time between insertion and removal of a voice prosthesis
3.4
leakage

the rate at which the test media leaks from the oesophageal side to the tracheal side of the voice

prosthesis
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ISO 21917:2021(E)
3.5
opening pressure
minimal pressure that opens the valve
3.6
outer shaft diameter
largest outer diameter of the voice prosthesis shaft between the flanges
3.7
shaft length

distance between the oesophageal and the tracheal flanges of the voice prosthesis

3.8
type test

test on a representative sample of the voice prosthesis with the objective of determining if the voice

prosthesis as designed and manufactured can meet specified requirements

[SOURCE: IEC 60601-1:2005, 3.135, modified by replacing "equipment" by "voice prosthesis" and making

more generic]
3.9
voice prosthe
...

ISO/PRF 21917

Anaesthetic and respiratory equipment -- Voice prostheses

Anaesthetic and respiratory equipment -- Voice prostheses

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Anaesthetic and respiratory equipment -- Voice prostheses

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