SIST EN ISO 19223:2021

Lung ventilators and related equipment - Vocabulary and semantics (ISO 19223:2019)

This document establishes a vocabulary of terms and semantics for all fields of respiratory care involving mechanical ventilation, such as intensive-care ventilation, anaesthesia ventilation, emergency and transport ventilation and home-care ventilation, including sleep-apnoea breathing-therapy equipment. It is applicable
—     in lung ventilator and breathing-therapy device standards,
—     in health informatics standards,
—     for labelling on medical electrical equipment and medical electrical systems,
—     in medical electrical equipment and medical electrical system instructions for use and accompanying documents,
—     for medical electrical equipment and medical electrical systems interoperability, and
—     in electronic health records.
This document is also applicable to those accessories intended by their manufacturer to be connected to a ventilator breathing system or to a ventilator, where the characteristics of those accessories can affect the basic safety or essential performance of the ventilator and ventilator breathing system.
NOTE    This document can also be used for other applications relating to lung ventilation, including non-electrical devices and equipment, research, description of critical events, forensic analysis and adverse event (vigilance) reporting systems.
This document does not specify terms specific to breathing-therapy equipment, or to physiologic closed-loop ventilation, high-frequency ventilation or negative-pressure ventilation; nor to respiratory support using liquid ventilation or extra-corporeal gas exchange, or oxygen, except where it has been considered necessary to establish boundaries between bordering concepts.

Beatmungsgeräte und zugehörige Geräte - Terminologie und Semantik (ISO 19223:2019)

Dieses Dokument legt ein Vokabular der Begriffe und Semantiken für alle Bereiche der Beatmungsversorgung fest einschließlich mechanischer Beatmung, wie etwa Intensiv-Beatmung, Anästhesie-Beatmung, Rettungs- und Transport-Beatmung und Heim-Beatmung, einschließlich Schlaf-Apnoe-Atemtherapie-Geräte. Es gilt für:
- Normen für Beatmungsgeräte und Atem-Therapiegeräte,
- Normen zu medizinischer Informatik,
- die Beschriftung medizinischer elektrischer Geräte und medizinischer elektrischer Systeme,
- Gebrauchsanweisungen und Begleitdokumente für medizinische elektrische Geräte und medizinische elektrische Systeme,
- die Interoperabilität von medizinischen elektrischen Geräten und medizinischen elektrischen Systemen, und
- elektronische Gesundheitsakten.
Dieses Dokument gilt auch für Zubehör, für das der Hersteller den Anschluss an ein Atemsystem des Beatmungsgeräts oder ein Beatmungsgerät vorsieht, bei dem die Merkmale dieses Zubehörs die Sicherheit oder wesentlichen Leistungsmerkmale des Beatmungsgeräts und des Atemsystems des Beatmungsgeräts beeinflussen können.
ANMERKUNG Dieses Dokument kann darüber hinaus für andere Anwendungen in Verbindung mit der Lungen-Beatmung einschließlich nichtelektrischer Geräte und Einrichtungen, der Forschung, der Beschreibung kritischer Ereignisse, der forensischen Analyse und in Meldesystemen für unerwünschte Ereignisse (Überwachung) verwendet werden.
Dieses Dokument legt keine spezifischen Begriffe für Atem-Therapiegeräte, oder die physiologisch geschlossenen Regelkreise der Beatmung, die Hochfrequenz-Beatmung oder die Unterdruckbeatmung oder für den extrakorporalen Gasaustausch oder Sauerstoffaustausch fest, außer wo dies als erforderlich angesehen wird, um Grenzen zwischen benachbarten Konzepten festzulegen.

Ventilateurs pulmonaires et équipement associé - Vocabulaire et sémantique (ISO 19223:2019)

Le présent document établit un vocabulaire de termes et de sémantique pour tous les domaines des soins respiratoires impliquant une ventilation mécanique, tels que la ventilation en soins intensifs, la ventilation en anesthésie, la ventilation d'urgence et de transport et la ventilation à domicile, y compris le matériel de traitement respiratoire de l'apnée du sommeil. Il est applicable:
—          dans les normes relatives aux ventilateurs pulmonaires et aux dispositifs de thérapie respiratoire;
—          dans les normes relatives à l'informatique de santé;
—          pour l'étiquetage d'équipements et de systèmes électromédicaux;
—          dans les instructions d'utilisation et documents d'accompagnement relatifs aux équipements et systèmes électromédicaux;
—          pour l'interopérabilité d'équipements et de systèmes électromédicaux; et
—          dans les dossiers médicaux informatisés.
Le présent document est également applicable aux accessoires conçus par leur fabricant pour être raccordés au système respiratoire d'un ventilateur ou à un ventilateur, lorsque les caractéristiques de ces accessoires peuvent affecter la sécurité de base ou les performances essentielles du ventilateur et du système respiratoire du ventilateur.
NOTE       Le présent document peut également être utilisé pour d'autres applications en rapport avec la ventilation pulmonaire, notamment les dispositifs et équipements non électriques, la recherche, la description d'événements critiques, l'analyse médico-légale et les systèmes de notification (veille) des effets indésirables.
Le présent document ne spécifie pas de termes spécifiques aux équipements de thérapie respiratoire, à la ventilation physiologique en boucle fermée, à la ventilation à haute fréquence ou à la ventilation à pression négative; ni à l'aide respiratoire par ventilation liquide, par échange gazeux extracorporel ou par oxygène, excepté lorsqu'il a été jugé nécessaire d'établir des limites entre des concepts voisins.

Pljučni ventilatorji in pripadajoča oprema - Slovar in semantika (ISO 19223:2019)

General Information

• Status: Published
• Public Enquiry End Date: 19-Jan-2021
• Publication Date: 24-May-2021
• ICS: 01.040.11 - Health care technology (Vocabularies)
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: VAZ - Healthcare
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 13-May-2021
• Due Date: 18-Jul-2021
• Completion Date: 25-May-2021
• Ref Project: EN ISO 19223:2021 - Lung ventilators and related equipment - Vocabulary and semantics (ISO 19223:2019)

Overview

SIST EN ISO 19223:2021 (ISO 19223:2019) defines a standardized vocabulary and semantics for lung ventilators and related equipment. Its purpose is to remove ambiguity in the language used for mechanical ventilation across clinical domains - intensive care, anaesthesia, emergency and transport, home care and sleep-apnoea therapy - and to support consistent communication between manufacturers, clinicians, health‑IT systems and regulators.

This standard is primarily a terminology document: it establishes precise definitions, relationships and conventions so that ventilator settings, modes and ventilator–patient interactions can be described, recorded and exchanged unambiguously.

Key topics and technical scope

The document organizes and standardizes terms across major technical areas (see main clause headings):

• General artificial‑ventilation terminology
• Breath terminology and types of breaths
• Lung inflation terminology
• Time, phase and cycle terminology
• Rate terminology (primary and secondary rate concepts)
• Pressure terminology (including baseline and PEEP concepts)
• Flow and volume terminology
• Initiation and termination of breaths
• Mode and bi‑level terminology
• Safety limits and alarm terminology
• Gas port and accessory terminology

It also includes informative annexes offering rationales, illustrations, classification tables, implementation guidance and an alphabetized index of defined terms. The standard provides semantics essential for device labelling, instructions for use, interoperability and electronic health records.

Note: the standard intentionally excludes many highly specialized areas (e.g., specific breathing‑therapy equipment terms, physiologic closed‑loop, high‑frequency or negative‑pressure ventilation, liquid ventilation and extracorporeal gas exchange), except where needed to define boundaries.

Practical applications - who uses this standard

• Medical device manufacturers - for consistent product specifications, UI labels and mode naming.
• Clinical engineers and biomed teams - for safe device integration, maintenance and alarm interpretation.
• Clinicians and respiratory therapists - to reduce misinterpretation of ventilator settings across platforms.
• Health‑IT and interoperability implementers - for mapping ventilator data into electronic health records (EHRs) and data exchange standards.
• Standards writers and regulators - to harmonize device standards, labelling and conformity assessments.
• Researchers, incident investigators and vigilance/reporting systems - for precise event description, forensic analysis and data aggregation.

Related standards and governance

• Prepared by ISO/TC 121 (Anaesthetic and respiratory equipment) and adopted as EN ISO 19223:2021 by CEN/TC 215.
• Works alongside health informatics and medical electrical equipment standards to enable safe ventilator interoperability and consistent clinical documentation.

Keywords: ISO 19223, lung ventilators standard, ventilator vocabulary, ventilation terminology, mechanical ventilation, ventilator interoperability, PEEP, breath terminology, medical device labelling.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2021
Pljučni ventilatorji in pripadajoča oprema - Slovar in semantika (ISO 19223:2019)
Lung ventilators and related equipment - Vocabulary and semantics (ISO 19223:2019)
Beatmungsgeräte und zugehörige Geräte - Terminologie und Semantik (ISO
19223:2019)
Ventilateurs pulmonaires et équipement associé - Vocabulaire et sémantique (ISO
19223:2019)
Ta slovenski standard je istoveten z: EN ISO 19223:2021
ICS:
01.040.11 Zdravstveno varstvo Health care technology
(Slovarji) (Vocabularies)
11.040.10 Anestezijska, respiratorna in Anaesthetic, respiratory and
reanimacijska oprema reanimation equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 19223
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 01.040.11; 11.040.10
English Version
Lung ventilators and related equipment - Vocabulary and
semantics (ISO 19223:2019)
Ventilateurs pulmonaires et équipement associé - Beatmungsgeräte und zugehörige Geräte -
Vocabulaire et sémantique (ISO 19223:2019) Terminologie und Semantik (ISO 19223:2019)
This European Standard was approved by CEN on 12 April 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19223:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 19223:2019 has been prepared by Technical Committee ISO/TC 121 "Anaesthetic and
respiratory equipment” of the International Organization for Standardization (ISO) and has been taken
over as EN ISO 19223:2021 by Technical Committee CEN/TC 215 “Respiratory and anaesthetic
equipment” the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2021, and conflicting national standards shall
be withdrawn at the latest by April 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 19223:2019 has been approved by CEN as EN ISO 19223:2021 without any modification.

INTERNATIONAL ISO
STANDARD 19223
First edition
2019-07
Lung ventilators and related
equipment — Vocabulary and
semantics
Ventilateurs pulmonaires et équipement associé — Vocabulaire et
sémantique
Reference number
ISO 19223:2019(E)
©
ISO 2019
ISO 19223:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 19223:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 * Scope . 1
2 Normative references . 1
3 * Terms, definitions, symbols, and abbreviated terms . 1
3.1 General artificial-ventilation terminology . 2
3.2 Breath terminology . 9
3.3 Lung inflation terminology .13
3.4 * Time, phase and cycle terminology .18
3.5 * Rate terminology .23
3.5.1 Preferred rate concepts.23
3.5.2 Secondary rate concepts — Rate terms for use if required for specific purposes 25
3.6 Pressure terminology .26
3.7 Flow terminology .30
3.8 Volume terminology .34
3.9 Initiation and termination terminology .38
3.10 * Baseline and PEEP terminology .43
3.11 * Mode terminology .48
3.12 * Bi-level terminology .60
3.13 Safety limits and alarm terminology .64
3.14 Gas port terminology .67
Annex A (informative) Rationales and guidance.69
Annex B (informative) Conceptual relationships between ventilator actions and types of breath .75
Annex C (informative) Illustrations of ventilation terms .77
Annex D (informative) Classification of inflation-types .109
Annex E (informative) Classification of ventilation-modes .114
Annex F (informative) Concepts relating to baseline airway pressures and PEEP as used in
this document .116
Annex G (informative) Conventions followed in this document .125
Annex H (informative) Implementation guidance for the vocabulary of this document .127
Annex I (informative) Equivalence declaration tables.129
Annex J (informative) Terminology — Alphabetized index of defined terms .132
Bibliography .139
ISO 19223:2019(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 4, Vocabulary and semantics.
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.
iv © ISO 2019 – All rights reserved

ISO 19223:2019(E)
Introduction
The characteristics of ventilation-modes of current automatic lung ventilators are often not well
understood. The current terminology used for their description is based on that introduced in the early
days of mechanical ventilation, but with the advances in ventilators, and ventilation-modes that have
evolved over recent years, the language used has been continuously adapted. In the absence of any
effective international coordinating action, this has inevitably led to increasing inconsistencies in the
way in which well-established terms and their derivatives are used.
To further compound the difficulties in understanding these complexities, some ventilator manufacturers
have created new proprietary terms to describe these alternative ways of ventilating patients, and
others have used existing terms with different meanings in different situations. This has led to patient
safety hazards, an example being that lung ventilator clinical orders (settings) for one model of ventilator
can be quite different from those required to get the same result from a different ventilator.
Recognizing these difficulties, ISO Technical Committee ISO/TC 121 requested its Subcommittee, SC 4,
to completely review the terminology and semantics for patient ventilation with a view to compiling a
standardized vocabulary that is applicable to current and, as far as possible, future practice. The primary
objective was to use as much existing terminology as possible, while clarifying its meaning and limiting
its potential for misuse by defining it more precisely. New terms were only introduced where there was
no alternative, either in order to name new concepts or where the misuse of existing vocabulary has
become so widespread that the term has become meaningless or unacceptably ambiguous. Importance
was placed on a vocabulary that would communicate a clear mental model of how the selected settings
would determine the interaction between the patient and the ventilator.
In order to achieve a vocabulary that is coherent, consistent and applicable to a range of fields such as
patient care, research, data collection and incident reporting, this document has been developed with the
participation, cooperation and assistance of members of other standards development organizations,
and of major international ventilator manufacturers. The applications include lung ventilators, medical
data systems facilitating clinical care and research, interoperability, incident reporting and equipment
maintenance.
The early work by the subcommittee in establishing how a standardized vocabulary should be
structured increasingly led to the conclusion that it would be necessary to revert to first principles.
It was recognized that much of the current terminology has its origins in the early use of automatic
ventilation, when the emphasis was inevitably on how best to save the lives of patients who could not
breathe for themselves and, consequently, only made basic provisions for the patient's own respiratory
activity. Since that time, ventilators have become increasingly interactive with the patient, such that it is
now necessary to consider their use from a ventilator-patient system perspective because it is no longer
possible, with any certainty, to predict ahead of time how that interaction will take place.
The terminology in this document is defined and used in a way that makes it capable of facilitating,
unambiguously, both the setting of a ventilator and how to describe and record the resultant ventilator-
patient interactions, continuously and at defined points within the course of ventilation. This includes
the result of the complex interactions that occur when additional breaths are taken during an assured-
inflation cycle, as can occur, for example, during APRV (airway pressure release ventilation).
This document seeks both to provide a consensus view and the basis for a coherent language for
describing ventilator function. Now that the fundamental concepts of artificial ventilation practice
within the scope of this document have matured, it has been possible to review the boundaries between
the various concepts of established ventilation-modes and the methods of artificially inflating a patient's
lungs and to formulate definitions that clarify the common elements and the distinctions. In particular,
the scopes of several concepts that were appropriate to earlier technology and practice have become
inadequate to encompass new developments and it was found necessary to subdivide them. Some of
their designating terms have, therefore, had to be deprecated, replaced or constrained using more
restrictive definitions, resulting in an inevitable reintroduction of some little-used legacy terms and
the need to create a few new terms.
ISO 19223:2019(E)
The overall objective is to encourage a more disciplined use of ventilator vocabulary so that operators
trained in the application of this document will be able to move easily from one ventilator to another
and operate each one, with confidence, after a minimum amount of training. Although it is recognized
that change will not be immediate, it is expected that this discipline will feed through into scientific
publications, textbooks and training so that, over time, a standardized basic language of artificial
ventilation will become internationally established.
Examples of the application of this document are illustrated in the figures of Annexes C and F but these
are not intended to indicate a requirement, nor to impose any restriction on the design of artificial
ventilation devices.
Included with many of the terms are notes to entry that provide supplementary information, including
explanations of the semantics of the term along with their classification schemes. This format is not
only a requirement of ISO 704 but, unlike with such information in an annex, ensures that it remains
associated with the term when viewed on the free-to-access ISO Online Browsing Platform.
Some of the terms in this document are principally intended for technical documents, informatics and
related applications, and might have little applicability to ventilator labelling and instructions for use.
In this document, the following print types are used:
Definitions: roman type.
Material appearing outside of tables, such as notes, examples and references: smaller type.
Terms defined in Clause 3 of this document or as noted, apart from those in the form of acronyms or
initialisms or when used in headings or tables: italic type.
In this document, the conjunctive “or” is used as an “inclusive or” so a statement is true if any
combination of the conditions is true.
The verbal forms used in this document conform to the usage described in ISO/IEC Directives, Part 2,
Annex H. For the purposes of this document, the auxiliary verb
— “shall” means that compliance with a requirement or a test is mandatory for compliance with this
document,
— “should” means that compliance with a requirement or a test is recommended but is not mandatory
for compliance with this document, and
— “may” is used to describe a permissible way to achieve compliance with a requirement or test.
An asterisk (*) as the first character of a title or at the beginning of a paragraph or table title indicates
that there is guidance or rationale related to that item in Annex A.
Colour coding is employed in most of the figures in Annexes B, C and F of this document to help
distinguish between some of the specific characteristics being illustrated. The coding used for each
figure, or set of figures, is provided either in its own specific key or in the introductory text of each
annex, as applicable.
NOTE The following figures and tables have been reproduced from Reference [34] with permission:
— Figures: B.1, C.1 to C.35 and F.1 to F.7;
— Tables: D.1 to D.3, E.1 and E.2.
vi © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 19223:2019(E)
Lung ventilators and related equipment — Vocabulary and
semantics
1 * Scope
This document establishes a vocabulary of terms and semantics for all fields of respiratory care
involving mechanical ventilation, such as intensive-care ventilation, anaesthesia ventilation, emergency
and transport ventilation and home-care ventilation, including sleep-apnoea breathing-therapy
equipment. It is applicable
— in lung ventilator and breathing-therapy device standards,
— in health informatics standards,
— for labelling on medical electrical equipment and medical electrical systems,
— in medical electrical equipment and medical electrical system instructions for use and accompanying
documents,
— for medical electrical equipment and medical electrical systems interoperability, and
— in electronic health records.
This document is also applicable to those accessories intended by their manufacturer to be connected to
a ventilator breathing system or to a ventilator, where the characteristics of those accessories can affect
the basic safety or essential performance of the ventilator and ventilator breathing system.
NOTE This document can also be used for other applications relating to lung ventilation, including non-
electrical devices and equipment, research, description of critical events, forensic analysis and adverse event
(vigilance) reporting systems.
This document does not specify terms specific to breathing-therapy equipment, or to physiologic closed-
loop ventilation, high-frequency ventilation or negative-pressure ventilation; nor to respiratory support
using liquid ventilation or extra-corporeal gas exchange, or oxygen, except where it has been considered
necessary to establish boundaries between bordering concepts.
2 Normative references
There are no normative references in this document.
3 * Terms, definitions, symbols, and abbreviated terms
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 http: //www .electropedia .org/
NOTE For convenience, an index and a list of sources of all defined terms used in this document are provided
in Annex J.
ISO 19223:2019(E)
3.1 General artificial-ventilation terminology
3.1.1
ventilator
lung ventilator
DEPRECATED: respirator
medical device or medical electrical equipment intended to provide artificial ventilation
Note 1 to entry: In cases of possible ambiguity the full term, lung ventilator, should be used.
Note 2 to entry: See also ventilation (3.1.9).
[SOURCE: ISO 80601-2-12:2011, 201.3.222, modified — Definition split into two terms (see 3.1.1 and
3.1.10).]
3.1.2
airway
connected, gas-containing cavities and passages within the respiratory system, that conduct gas
between the alveoli and the oral and nasal orifices on the surface of the face, or the patient-connection
port if an airway device is used
Note 1 to entry: This is a well-established term that is commonly used in isolation in references to the airway of a
patient. Depending on the context, it is sometimes more helpful to use the qualified term, patient's airway.
Note 2 to entry: See also airway device (3.1.3).
3.1.3
airway device
device intended for use as an interface between the patient-connection port of a ventilator and the
patient's airway, and which has no auxiliary features on which the ventilator is dependent for its normal
operation
EXAMPLE Endotracheal tube; tracheotomy tube; face mask; supralaryngeal airway.
Note 1 to entry: The connection to the patient's airway can be at the face (non-invasive) or internal to the patient
(invasive).
Note 2 to entry: A face mask that intentionally vents respiratory gas to atmosphere by means of a bleed orifice
is a functional part of the ventilator breathing system and therefore not an airway device. With that arrangement,
the face seal of the mask becomes the patient-connection port and there is no patient-connection port connector,
nor an airway device.
Note 3 to entry: See also patient-connection port (3.14.5), airway (3.1.2) and ventilator breathing system (3.1.18).
3.1.4
airway resistance
drop in pressure between the patient-connection port and the alveoli per unit rate of airway flow
Note 1 to entry: The airway resistance is normally expressed as a single coefficient, with the implicit assumptions
that it is independent of the flow rate and of the direction of flow. In practice, these assumptions are typically
only approximately valid.
Note 2 to entry: See also airway (3.1.2).
3.1.5
respiratory system compliance
respiratory compliance
DEPRECATED: lung compliance
elastic characteristic of the lung expressed as the change in lung volume per unit change of airway
pressure in the absence of respiratory activity
Note 1 to entry: In addition to its direct reference, this term or its symbol, C , is used, in context or by qualification,
rs
to designate this concept as a measured quantity (3.1.20).
2 © ISO 2019 – All rights reserved

ISO 19223:2019(E)
Note 2 to entry: The respiratory system compliance is normally expressed as a single coefficient, with the implicit
assumptions that it is independent of the volume of gas in the lung and of any hysteresis between increasing and
decreasing volumes. In practice, these assumptions are typically only approximately valid.
Note 3 to entry: Respiratory system compliance is typically determined by a static measurement once the airway
pressure has stabilized during an inspiratory pause. In mechanically ventilated patients it is typically determined
as either a static compliance or a dynamic compliance. There might be differences between the values obtained by
these different methods, not only due to the method itself but also due to viscoelastic effects, pressure balancing
throughout the slower compartments of the lungs and possible recruitment effects.
Note 4 to entry: It is sometimes more applicable to express this characteristic as lung elastance, which is simply
the inverse of respiratory system compliance.
Note 5 to entry: See also lung (3.1.16), airway pressure (3.6.1), respiratory activity (3.2.6), respiratory system
(3.1.17), inspiratory pause (3.4.12), pulmonary compliance (3.1.6), static compliance (3.1.7) and dynamic compliance
(3.1.8).
3.1.6
pulmonary compliance
elastic characteristic of the lungs expressed as the change in the lung volume per unit change of the
difference between the alveolar pressure and the pressure in the pleural space
Note 1 to entry: In addition to its direct reference, this term or its symbol, C , is used, in context or by qualification,
L
to designate this concept as a measured quantity (3.1.20). The specific symbol, C , has been adopted because of
L
its established usage in the scientific community to represent the ‘compliance of the lungs’.
Note 2 to entry: The pulmonary compliance is the compliance coefficient relating specifically to the lungs, as
distinct from the respiratory system compliance coefficient, which relates to the whole of the respiratory system
and, therefore, includes the compliance of the thoracic cage. For most patients it is not clinically necessary to
differentiate between the compliance of the lungs alone, and the compliance of the respiratory system, so the more
directly measurable respiratory system compliance provides sufficient information. If an impaired respiratory
system is indicated, the difference might be significant and can justify the more invasive and skilled procedure
required to obtain a measurement of pressure in the pleural space (the intrapleural pressure) and, thereby, that
of the pulmonary compliance.
Note 3 to entry: The difference between the alveolar pressure and the pleural pressure is typically referred to as
the transpulmonary pressure.
Note 4 to entry: The pulmonary compliance is normally expressed as a single coefficient, with the implicit
assumptions that it is independent of the volume of gas in the lungs, of any hysteresis between increasing and
decreasing volumes and of any variation of the pleural pressure within the pleural space. In practice, these
assumptions are typically only approximately valid.
Note 5 to entry: See also lung (3.1.16), airway pressure (3.6.1), respiratory system (3.1.17) and respiratory system
compliance (3.1.5).
3.1.7
static compliance
respiratory system compliance determined, under quasi-static conditions and while connected to a
ventilator, as the measured change in inspiratory volume per unit change in the measured plateau
inspiratory pressure relative to the measured total PEEP
Note 1 to entry: In addition to its direct reference, this term or its symbol, C , is used, in context or by
stat
qualification, to designate this concept as a measured quantity (3.1.20).
Note 2 to entry: For the purposes of this measurement, quasi-static conditions are considered to occur during a
respiratory phase of low airway flow and no significant respiratory activity.
Note 3 to entry: Expressed as an equation: static compliance = inspiratory volume / (plateau pressure – total PEEP).
If the presence of auto-PEEP is not suspected or a value for total PEEP is not readily available, the set BAP may be
used as a substitute for total PEEP in this equation.
Note 4 to entry: See also respiratory system compliance (3.1.5), inspiratory volume (3.8.3), plateau inspiratory
pressure (3.6.4), total PEEP (3.10.6), auto-PEEP (3.10.7) and BAP (3.10.2).
ISO 19223:2019(E)
3.1.8
dynamic compliance
respiratory system compliance determined during normal mechanical ventilation
Note 1 to entry: In addition to its direct reference, this term or its symbol, C , is used, in context or by
dyn
qualification, to designate this concept as a measured quantity (3.1.20).
Note 2 to entry: Dynamic compliance is a dynamically calculated value obtained during normal mechanical
ventilation by measuring the rate of change of inspiratory volume per unit change of airway pressure. A least
squares or other curve-fitting algorithm can be used, typically in conjunction with the equation of motion for
the respiratory system, to correct for any transient dynamic effects. When this term is used, the basis of the
calculation employed should be made available to the user.
3.1.9
ventilation
cyclical movement of a respirable gas into and out of the lungs
Note 1 to entry: This might be by external or spontaneous means, or by a combination of both.
Note 2 to entry: See also spontaneous breath (3.2.3), artificial ventilation (3.1.10), automatic ventilation (3.1.12),
mechanical ventilation (3.1.11), negative-pressure ventilation (3.1.14), positive-pressure ventilation (3.1.13) and
inflation (3.3.1).
3.1.10
artificial ventilation
intermittent elevation of the pressure in the patient's airway relative to that in the lungs by external
means with the intention of augmenting, or totally controlling, the ventilation of a patient
EXAMPLE Means used to provide artificial ventilation are manual resuscitation; mouth-to-mouth
resuscitation; automatic ventilation; mechanical ventilation.
Note 1 to entry: Common classifications of areas of application of artificial ventilation are: emergency; transport;
home-care; anaesthesia; critical care; rehabilitation.
Note 2 to entry: Classifications used to denote means used for artificial ventilation include: positive-pressure;
negative-pressure; gas-powered; operator-powered; electrically-powered.
Note 3 to entry: Negative-pressure ventilation elevates the relative pressure in the airway by intermittently
lowering the pressure in the lungs.
[SOURCE: ISO 80601-2-12:2011, 201.3.22, modified — Definition split into two terms (3.1.1 and 3.1.10).]
3.1.11
mechanical ventilation
artificial ventilation by means of a mechanical device
Note 1 to entry: This term has become the commonly used term for any form of artificial ventilation that involves
specifically designed equipment comprising mechanical parts only or mechanical and electrical/electronic parts.
Note 2 to entry: A mechanical ventilator can provide artificial ventilation automatically or by manual operation
and delivers either positive-pressure ventilation or negative-pressure ventilation.
3.1.12
automatic ventilation
continuous artificial ventilation by means of an automatic device
Note 1 to entry: Automatic ventilators deliver either positive-pressure ventilation or negative-pressure ventilation.
Note 2 to entry: This term can be used for the specific designation of the large class of mechanical ventilators
that are not manually operated. The designation includes all ventilators that operate without continuous human
intervention, extending from basic automatically-cycled resuscitators to ventilators providing physiological
closed-loop control.
4 © ISO 2019 – All rights reserved

ISO 19223:2019(E)
3.1.13
positive-pressure ventilation
PPV
DEPRECATED: IPPV
artificial ventilation achieved by the intermittent elevation of the airway pressure above any set BAP
Note 1 to entry: This is a general term for artificial ventilation achieved by the intermittent application of a raised
pressure to some part of the patient's airway in order to assist or control an increase in the volume of gas in the
lung. Each such intermittent elevation of the airway pressure constitutes an inflation.
Note 2 to entry: The original term for this means of applying artificial ventilation was intermittent positive-
pressure ventilation (IPPV) but since the almost universal adoption of the practice of retaining some level of
positive airway pressure at the end of expiration the ‘positive pressure’ is no longer intermittent because the
airway pressure is continuously positive. Although it is only possible to achieve positive-pressure artificial
ventilation by intermittently changing the airway pressure, whether it is by intermittent elevation or intermittent
release of the pressure, depends on the objective and settings. With its now wide acceptance in the practice of
artificial ventilation, the qualifying term ‘positive-pressure’ is, therefore, all that is required for its distinction.
Note 3 to entry: See also artificial ventilation (3.1.10), inflation (3.3.1), airway pressure (3.6.1), set (3.1.19), BAP
(3.10.2), airway (3.1.2), lung (3.1.16) and expiration (3.2.11).
3.1.14
negative-pressure ventilation
NPV
artificial ventilation achieved by intermittently changing a negative pressure applied to the exterior of
the patient's thorax
Note 1 to entry: This document does not include terms specific to negative-pressure ventilation.
Note 2 to entry: See also Clause 1.
3.1.15
NIV
non-invasive ventilation
positive-pressure ventilation without the use of an invasive airway device
Note 1 to entry: The connection to the patient is typically by means of a specially designed face or nasal mask.
Note 2 to entry: The provision of NIV does not, in itself, require dedicated ventilation-modes although some
might be more suited to its use, but it does typically require certain compensating measures, particularly those
relating to the possibility of increased and variable leakage. These can include, added, extended or deactivated
compensations, modified alarms limits, the deactivation of some alarms and the modification of inflation initiation
and termination criteria.
Note 3 to entry: On ventilators intended for NIV only, these compensations are classified as a permanently active
NIV adjunct. On ventilators where the compensations made to suit NIV are selectable as an option, although also
adjunctive in their actions, these have been typically classified as an NIV ventilator operational mode.
Note 4 to entry: See also positive-pressure ventilation (3.1.13), airway device (3.1.3), ventilator (3.1.1), ventilator
operational mode (3.11.1) and adjunct (3.11.4).
3.1.16
lung
each of the pair of compliant organs within the ribcage (thorax), bounded by the terminal bronchiole
and the visceral pleura, which during ventilation provide gas/blood interfaces that enable oxygen from
the gas to pass into the blood and carbon dioxide to be removed
Note 1 to entry: In specific reference to the pair of these organs, in this document the inflection ‘lungs’ is used.
ISO 19223:2019(E)
Note 2 to entry: In accordance with what has become common practice in the absence of a more suitable term,
this term in its singular form is also used in this document to reference the connected, respiratory-gas containing
cavities within the respiratory system, consisting of the airway and the lungs. Examples of this common practice
in applications that are outside the scope of this document are: lung function; lung disease; lung compliance; lung
mechanics; test lung. Other established examples are lung ventilator; lung elastance; lung protective strategy.
Note 3 to entry: Although there are no such references in this document, if in the application of this document
a need arises to refer to just ‘one of the lungs’ then, in order to avoid any possible ambiguity, it should always be
identified as such, or as the ‘left lung’ or ‘right lung’.
Note 4 to entry: See also ventilation (3.1.9) and breathe (3.2.2).
3.1.17
respiratory system
anatomical system related to breathing including the airway, lungs, chest wall, pleural space, brainstem
respiratory control centre, phrenic nerves, neuromuscular junctions, diaphragm and accessory muscles
of ventilation
3.1.18
ventilator breathing system
VBS
anaesthesia breathing system
pathways through which gas flows to or from the patient at respiratory pressures, bounded by the port
through which respirable gas enters, the patient-connection port and the gas exhaust port
Note 1 to entry: These pathways typically extend within and outside the body of the ventilator, with those outside
being operator-detachable.
Note 2 to entry: The port of entry of a respirable gas into the ventilator breathing system can be inside the body
of the ventilator and should not be confused with an external connection port into which respirable gas enters
before being reduced to respirable pressures.
Note 3 to entry: See also port (3.14.1), patient-connection port (3.14.5), exhaust port (3.14.2) and ventilator (3.1.1).
Note 4 to entry: The admitted term is included in this document for use in reference to the specific class of
ventilators that are configured to ventilate patients with an anaesthetic gas mixture. With this application, the
definition may be made more specific with ‘respirable gas’ becoming ‘anaesthetic gases and the ‘port through
which respirable gas enters’ becoming the ‘fresh-gas inlet’.
[SOURCE: ISO 4135:2001, 3.1.6 and 4.1.1, and ISO 80601-2-12:2011, 201.3.221, modified — Rephrased.]
3.1.19
set
allocated a specific value
EXAMPLE 1 A set pressure limit.
EXAMPLE 2 The set inspiratory pressure.
Note 1 to entry: Set is used in this document as a prefix to distinguish an intended value for a controlled ventilation
variable from a measured or actual value of the same quantity.
Note 2 to entry: The use of this term is not required if the distinction from a measured or actual value is evident
from the context of use.
Note 3 to entry: A set value might be determined directly by the operator or indirectly by selection of an algorithm
that determines the setting based on other settings or measurements.
Note 4 to entry: See also actual value (3.1.22) and the references to settings in Annexes A, C and D, and G.4.
6 © ISO 2019 – All rights reserved

ISO 19223:2019(E)
3.1.20
measured
determined by a measuring device or system
Note 1 to entry: This term is used in this document as a prefix to distinguish the value of a quantity as determined
by a measuring device or system, from an actual value or set value of the same quantity.
Note 2 to entry: Measured values might be displayed or recorded as discrete values or as a continuous waveform.
Note 3 to entry: The use of this term is not required if the distinction from a set or actual value is evident from the
context of use.
Note 4 to entry: See also set (3.1.19), actual value (3.1.22) and G.4.
3.1.21
preset
one of a set of stored configuration parameter(s), including selection of algorithms and initial values for
use by algorithms, which affects or modifies the performance of the ventilator
Note 1 to entry: Presets are commonly configured by the manufacturer or a responsible organization.
Note 2 to entry: Access to a preset value is typically controlled by
— a tool,
— a responsible-organization password and a technical description, separate from the instructions for use,
— an individual operator password,
— voice recognition, or
— biometric means.
3.1.22
actual value
value of a quantity as it exists in fact
Note 1 to entry: This is the true value of a quantity, which might, or might not, be determinable by a
measuring device.
Note 2 to entry: The definitions of terms denoting quantities, in this document, denote the actual value of that
quantity. Set values are the means by which an operator informs the ventilator of the intended actual value, and
measured values are displays or records of the actual value, to the accuracy and resolution of the measuring system.
3.1.23
limit
point or level beyond which the value of a parameter may not pass without an action by the ventilator
Note 1 to entry: The action might be a notification or the implementation of means to prevent or mitigate a
hazardous situation.
Note 2 to entry: In this document, this term is restricted to the designation of safety constraints that provide
patient protection that is completely independent of the controlled ventilation parameters.
Note 3 to entry: An alarm system uses an alarm limit in determining an alarm condition.
Note 4 to entry: See also alarm system, alarm limit and alarm condition (Annex J) and safety limits and alarm
terminol
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