ISO 19223-2:2025

International
Standard
ISO 19223-2
First edition
Lung ventilators and related
2025-04
equipment — Vocabulary and
semantics —
Part 2:
High frequency and jet ventilation
Ventilateurs pulmonaires et équipement associé — Vocabulaire et
sémantique —
Partie 2: Ventilation haute fréquence et à jet
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General high-frequency ventilation terminology .2
3.2 High-frequency-ventilation equipment terminology .3
3.3 High-frequency-ventilation mode terminology .4
3.4 Pressure terminology . .7
3.5 Flow and volume terminology .7
3.6 Waveform terminology .8
Annex A (informative) Classification of ventilation-modes . 9
Annex B (informative) Illustration of high-frequency ventilation terms .10
Bibliography .15
Index . 16

iii
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
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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 document 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).
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This document was prepared by Technical Committee ISO/TC 121, Anaesthetic and respiratory equipment,
Subcommittee SC 4, Vocabulary and semantics.
A list of all parts in the ISO 19223 series can be found on the ISO website.
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
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, the terminology and semantics for patient ventilation have been reviewed to
compile a standardized vocabulary that is applicable to current and, as far as possible, future practice. The
primary objective was to use as terms language already in use in the field of lung ventilation where possible,
while clarifying the meaning of each term 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 ventilatormanufacturers. The applications include lung ventilators, medical data systems
facilitating clinical care and research, interoperability, incident reporting and equipment maintenance.
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 are not able
to 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.
The ISO 19223 series does not specify terms specific to physiologic closed-loop 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.
In general, the ISO 19223 series is intended 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.
The overall objective is to encourage a more disciplined use of ventilator vocabulary so that users 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

v
training so that, over time, a standardized basic language of artificial ventilation will become internationally
established.
vi
International Standard ISO 19223-2:2025(en)
Lung ventilators and related equipment — Vocabulary and
semantics —
Part 2:
High frequency and jet ventilation
1 Scope
This document defines terms for:
— high-frequency oscillatory ventilation (HFOV);
— percussive ventilation, including high-frequency percussive ventilation (HFPV);
— jet ventilation, including high frequency jet ventilation (HFJV);
— modes that combine high-frequency and physiological-rate ventilation.
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
ventilatorbreathing system or to a ventilator, where the characteristics of those accessories can affect the
basic safety or essential performance of the ventilator or 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.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology 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 General high-frequency ventilation terminology
3.1.1
high-frequency ventilator
ME equipment intended to provide ventilation of the lungs of the patient when connected to the airway of the
patient using a frequency greater than 150 inflations/min
Note 1 to entry: Inflation frequencies are specified as per minute solely when differentiating from conventional-rate
ventilation.
Note 2 to entry: A high-frequency ventilator can have a range of inflation frequency that includes values below 150
inflations/min.
3.1.2
HFV breathing system
pathways through which gas flows to or from the high-frequency ventilator (3.1.1) and to or from the patient
3.1.3
HFV frequency
number of HFV inflations (3.1.5) that are set to occur in a specified period of time, expressed as HFV inflations
per second
3.1.4
HFV I:E ratio
ratio of the inspiratory time to the expiratory time in a respiratory cycle
Note 1 to entry: In addition to its direct reference, this term or its symbol, I:E, may be used, in context or by qualification,
to designate this concept as a set quantity or a measured quantity.
Note 2 to entry: By mathematical convention, a colon or a slash is used to designate a ratio between two values so the
addition of the word ‘ratio’ is not strictly necessary. However, its addition is widely practiced and is considered to add
to the readability of descriptive texts and lists, but in this document, its use is optional.
Note 3 to entry: In jet ventilation, there is no expiration defined or controlled by the equipment; the ‘expiratory time’
is the duration of the pause between HFV inflations (3.1.5).
EXAMPLE Ventilation using an inspiratory time of 0,1 s and an expiratory time of 0,15 s is described as having HFV
I:E ratio of 1:1,5 or an inspiratory time fraction of 0,4.
3.1.5
HFV inflation
ventilator action intended to deliver a volume of gas into the lungs and repeated at a set frequency
3.1.6
HFV volume
volume of gas delivered through the patient-connection port or at the distal outlet of the jet system during an
HFV inflation (3.1.5)
Note 1 to entry: The effective inspiratory tidal volume delivered to the lung can be variable. The leakage of uncuffed
tracheal tubes and even small changes in resistance or compliance of the respiratory system (e.g. due to secretions in
the airways, through the use of a different HFV breathing system or tracheal tube) can reduce the volume delivered to
the lung. Entrainment can result in an effective volume greater than the set HFV volume, and variable depending on
upper airway resistance.
Note 2 to entry: The achievable HFV volume depends characteristically on the HFV frequency (3.1.3). In general, lower
HFV frequencies permit higher HFV volumes.
Note 3 to entry: The HFV volume significantly influences CO elimination.
Note 4 to entry: HFV volume can be a setting or a measurement. Measurement of HFV volume is not available on all
commercially available high frequency ventilators.

Note 5 to entry: The term HFV volume can be used to represent an increase of the volume of gas in the lung either as a
setting, or as a measurable parameter. In some devices, in particular those characterised as providing high-frequency
jet ventilation (3.2.4), the HFV volume is controlled directly, as a controlled flow is provided to the jet catheter with
negligible compliance volume between the flow control valve and the patient airway. In other high frequency ventilators
the HFV volume is uncontrolled, as the high-frequency ventilation is provided using a variable pressure source. In this
case this term can only be used to represent an actual or monitored value. For some high-frequency ventilators, the
value is neither set nor monitored by the high-frequency ventilator.
3.1.7
HFV waveform
setting that determines the pressure, volume or flow waveform delivered by the high-frequency ventilator
EXAMPLE sinusoidal waveform (3.6.1)rectangular waveform (3.6.2).
3.2 High-frequency-ventilation equipment terminology
3.2.1
high-frequency ventilation
ventilation using a frequency greater than 150 inflations/min
Note 1 to entry: Inflation frequencies are specified as per minute solely when differentiating from conventional-rate
ventilation.
Note 2 to entry: Although the pressure fluctuations can be generated using a variety of different mechanisms, the
clinical effect is determined solely by the pressure or flow waveform. It is therefore not appropriate to differentiate
between HFOV generated by different means in this document.
3.2.2
high-frequency oscillatory ventilation
HFOV
ventilation using a tracheal tube airway interface with HFV inflations (3.1.5) provided at a frequency
exceeding 150 inflations/min superimposed onto a set mean airway pressure (3.4.2)
3.2.3
jet ventilation
ventilation where the inflation is created by a high-velocity flow of gas that is provided through a small-
diameter cannula into the patient airway
Note 1 to entry: the cannula can be rigid, and is inserted into the patient airway; the exhalation pathway is around the
exterior of the cannula.
Note 2 to entry: jet ventilation is primarily intended for treatment of patients for whom a conventional airway is not
appropriate, such as during oropharyngeal or laryngeal surgery.
Note 3 to entry: jet ventilation includes gas entrained into the airway by action of the jet in an unconstrained exhalation
pathway, and this entrainment augments the volume of gas entering the lungs
3.2.4
high-frequency jet ventilation
HFJV
jet ventilation (3.2.3) at a frequency exceeding 150 inflations/min
Note 1 to entry: there are existing jet ventilators that provide inflation frequencies both below and above 150 /min. Any
ventilator capable of providing jet ventilation at a frequency exceeding 150 /min is considered to be a high-frequency jet
ventilator
3.2.5
percussive ventilation
ventilation where the inflation is created by an intermittent jet of gas that is directed into a ventilator
breathing system to provide repetitive increases in pressure at the patient connecti
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