ISO/DIS 17256:2023(E)

ISO TC 121/SC 2

Date: 2023-01-06

Secretariat: ANSI

Anaesthetic and respiratory equipment – Respiratory therapy equipment — Tubing and connectors)

Equipement de thérapie respiratoire — Tubes et raccords

© ISO 2023, Published in Switzerland

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Contents

Foreword 5

Introduction 6

1 Scope 7

2 Normative references 8

3 Terms and definitions 8

4 General Requirements 8

4.1 General 8

4.2 Test methods and conditions 9

5 Materials 9

5.1 General 9

5.2 Biological assessment of gas pathways 9

6 Design requirements 9

6.1 General 9

6.2 Specific design requirements 9

6.3 Inlet connectors 11

6.4 Outlet connectors 11

7 Requirements for respiratory tubing, extension tubing and connectors supplied sterile 11

8 Packaging 11

9 Information supplied by the manufacturer 11

9.1 General 11

9.2 Information supplied by the manufacturer 11

Annex A (informative) Rationale 12

Annex B (normative) Therapy tubing connectors 14

Annex C (informative) Hazard identification for the purposes of risk assessment 1

Bibliography 2

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.

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This document was prepared by Technical Committee 121, Anaesthetic and respiratory equipment Subcommittee SC 2, Airways and related equipment.

This document 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.

This is the first edition and is based on the European Standard EN 13544-2^[2]:2009. The main changes include:

— the change of outlet from an elastomeric funnel to an R2 respiratory small-bore connector;

— requirements for extension tubing;

— requirements for respiratory tubing integrated with patient interface devices;

— a requirement to assess the biocompatibility of the materials of the devices that provide a gas pathway has been added;

— the dimensions of the nipple have been better defined;

— the option to specify a gas-specific threaded connection at the inlet of the respiratory tubing to replace the elastomeric funnel inlet connector has been made clearer;

— the gas-specific threaded inlet connectors now include gasses other than oxygen and air; and

— a hazard identification annex has been added.

Introduction

Respiratory tubing and connectors form the essential conduit between the patient interface and the gas supply device. The connectors specified in this document have been selected following the recommendations of a specially formed ISO/TC 121 advisory group (AG01) that considered the risks of misconnection with other medical devices commonly used within the same environment. The initial AG01 proposals were further developed by ISO/TC 121 WG1 and are to be published in an ISO Technical Specification (ISO/TS 22175^[1])^.

Respiratory tubing and connectors are used extensively in healthcare facilities and increasingly in the home healthcare environment where medically trained personnel are not always in attendance. These environments have been carefully considered during the deliberations of both WG1 and throughout the development of this document.

This document recognizes the significant use and the inherent safety of the EN 13544-2 ^[2] specified nipple as the gas outlet on respiratory gas supply devices and therefore specifies a compatible elastomeric (funnel) connector as the inlet of the respiratory tubing. This document also recognizes the high risks associated with misconnection of the previously prescribed elastomeric (funnel) connector at the outlet (patient end) of the tubing and has therefore specified the new R2 respiratory small-bore connector as the outlet connector if the respiratory tubing is not integrated with the patient interface device (e.g. face mask, nasal cannula0.

The concept of extension tubing, commonly used in homecare environments to provide flexibility of movement for the patient and special hospital environments, such as MRI units and endoscopy units, has now been included in this document with particular emphasis on the connectors.

Anaesthetic and respiratory equipment – Respiratory therapy tubing and connectors

This document specifies requirements for the respiratory tubing and connectors used to convey respirable gases to a patient in the healthcare and homecare environments and provide a safe connection between the gas supply device and the patient interface. Respiratory tubing and connectors are mainly used for delivery of oxygen, but can also be used for respirable air or oxygen/air mixtures and breathable medicinal gas mixtures such as oxygen/nitrous oxide or oxygen/helium mixtures. This document also specifies requirements for respiratory therapy extension tubing.

NOTE 1: The gas supply devices referred to in this document do not include Anaesthetic machines/workstations and ventilators.

NOTE 2: This document does not cover breathing tubes for breathing systems. These are specified in ISO 5367.

Figure 1 — Examples of combinations of respiratory tubing and connectors

NOTE: Figure 1 does not show all the possible combinations.

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 4135:2022, Anaesthetic and respiratory equipment — Vocabulary

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

ISO 20417:2021, Medical devices — Information to be supplied by the manufacturer

ISO 21920‑1:2021, Geometrical product specifications (GPS) — Surface texture: Profile — Part 1: Indication of surface texture

ISO 80369‑2,^[1] Small-bore connectors for liquids and gases in healthcare applications — Part 2: Respiratory small-bore connectors

For the purposes of this document, the terms and definitions given in ISO 4135, ISO 18190 and the following apply and are delineated throughout this document using italic type.

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

— IEC Electropedia: available at https://www.electropedia.org/

— ISO Online browsing platform: available at https://www.iso.org/obp

3.1

extension tubing

flexible conduit with connectors to extend the connection between the respiratory tubing (3.4) and the patient interface (3.3)

3.2

patient interface

that part connected to the patient

EXAMPLE: Mask, nasal cannula or connectors thereof.

3.3

permanently attached

not removable without the use of a tool

Note 1 to entry: There is rationale for this definition in A.3.3.

3.4

respiratory tubing

flexible conduit with connectors to connect the gas supply device to the patient interface (3.3) or extension tubing (3.1)

The requirements of ISO 18190:2016, Clause 4, shall apply.

The test methods included in this document are type tests and are carried out at (23 ± 2) °C; and at atmospheric pressure, unless otherwise specified.

NOTE: Flowrates, volumes and leakage rates are expressed at Standard Temperature and Pressure, Dry (STPD).

The requirements of ISO 18190:2016, Clause 5, shall apply.

Respiratory tubing, extension tubing and connectors shall meet the requirements of ISO 18562-1.

Check conformance by inspection of the manufacturer’s technical documentation.

The requirements of ISO 18190:2016, Clause 6, shall apply.

6.2.1 Respiratory tubing and extension tubing shall:

a) withstand an axial force of (40 ± 1,5) N; and

b) be fitted with permanently attached inlet and outlet connectors;

NOTE: There is rationale for this subclause in A.6.2.1.

Check conformance by the following test:

a) Apply an axial force of (40 ^-± 1,5) N at a rate of (50 ± 5) mm/min between each connector, in turn and the respiratory tubing.

b) Verify that the tubing does not fracture and the connectors do not detach from the respiratory tubing.

6.2.2 Respiratory tubing, integrated with a patient interface device shall not become detached from the patient interface device when subjected to an axial force of (40 ± 1,5) N.

Check conformance by the following test:

a) Apply an axial disconnection force of (40 ^-± 1,5) N at a rate of (50 ± 5) mm/min between the patient interface device and the respiratory tubing.

b) Verify that the respiratory tubing does not detach from the patient interface device.

6.2.3 Elastomeric funnel connectors shall not detach from a test nipple, as specified in Figure 2 and Table 1, when subjected to an internal pressure of (200 ± 10) kPa.

NOTE: There is rationale for this subclause in A.6.2.3.

Check conformance by the following test:

a) Assemble the elastomeric funnel to a test nipple, complying with Figure 1, using an engagement axial force of (45 ± 1,5) N and a clockwise torque of (25 ± 5) N.cm at a rate not exceeding 20 N.s^-1.

b) Subject the assembled connectors to a static internal pressure of (200 ± 10) kPa for >30 s.

c) Verify that the elastomeric funnel does not detach from the test nipple.

Figure 2 — Test Nipple

Table 1 — Dimensions of test nipple

6.2.4 The resistance to flow shall not exceed 0,9 kPa/m at a flow of 4 l/min.

Check conformance by the following test:

a) Set a flow of (4 ± 0,2) l/min through a length of respiratory tubing or extension tubing, complete with its connectors.

b) Measure the pressure drop across the length of tubing.

c) Verify that the pressure drop is less than 0,9 kPa/m.

6.2.5 Flow shall not reduce by more than 25 % when the respiratory tubing and extension tubing is bent in a semicircle of diameter three times its nominal outside diameter.

Check conformance by the following test:

a) Determine the pressure drop required to maintain a flow of 10 l/min across a straight length of respiratory tubing/extension tubing.

b) Maintain this pressure while bending the tubing in a semicircle of diameter three times its nominal outside diameter.

c) Verify that the flow is >7,5 l/min.

6.2.6 Respiratory tubing and extension tubing, including their connectors, shall not leak by more than 5 ml/min while being subjected to an internal pressure of (600 ± 10) kPa.

NOTE: There is rationale for this subclause in A.6.2.6.

Check conformance by the following test:

a) With the outlet occluded subject a length of respiratory tubing or extension tubing, complete with connectors, to an internal pressure of (600 ± 10) kPa.

b) Measure the flow required to maintain this pressure.

c) Verify that this flow <5 ml/min.

6.3.1 Respiratory tubing inlet connectors shall be one of the following:

a) an elastomeric funnel compatible with the nipple shown in Figure B.1;

b) for use with oxygen, oxygen/air mixtures and other breathable medical mixtures such as oxygen/nitrous oxide or oxygen/helium a nut and nipple complying with Figure B.2a); or

c) for use with medical air, a nut and nipple complying with Figure B.2b).

NOTE: There is rationale for this subclause in A.6.3.1.

Check conformance by functional testing.

6.3.2 Extension tubing inlet connectors shall be R2 socket small-bore connectors complying with ISO 80369-2.

Check conformance by functional testing.

Respiratory tubing and extension tubing outlet connectors shall be R2 cone small-bore connectors complying with ISO 80369-2.

Check conformance by functional testing.

The requirements of ISO 18190:2016, Clause 7, shall apply.

The requirements of ISO 18190:2016, Clause 8, shall apply.

The requirements of ISO 18190:2016, Clause 9 and ISO 20417:2021 shall apply.

The following warning shall be included in the instructions for use:

If intended for use with oxygen a statement to the effect – ‘a fire activated oxygen shut-off device should be fitted between the respiratory tubing and the patient interface device’.

1. 
   (informative)
   
   Rationale

This annex provides a concise rationale for the important requirements of this document and is intended for use by those who are familiar with the subject of this document but who have not participated in its development. An understanding of the reasons for the main requirements is considered essential for its proper application. Furthermore, as clinical practices and technologies change, it is believed that rationales for the present requirements will facilitate any revisions of this document necessitated by those developments.

The clauses in this annex have been so numbered to correspond to the clauses in this document to which they refer. The numbering is, therefore, not consecutive.

A.3.3   Permanently attached

Permanently attached has been defined as not being removable without the use of a tool. It is understood that nothing can be “permanently attached” in the true sense of the word but for the purposes of this document permanently attached is used to emphasise that the connectors should not be removable from the therapy/extension tubing without rendering the therapy/extension tubing unusable.

A.6.2.1   Inlet and outlet connectors

Requiring that tubing has permanently attached connectors at both ends is to prevent the use of cut-to-length tubing such as bubble tubing which can be misconnected to IV lines, urinary catheters, etc.

A.6.2.3   Test pressure for permanently attached funnel to respiratory tubing

ISO/TC 121/SC 2 discussed if having a common test pressure in 6.2.1 and 6.2.3 was necessary. It was decided to have two separate test pressures. In 6.2.3, which assesses the minimum retention characteristics of the elastomeric funnel to the test nipple, it was decided to use a test pressure of 200 kPa. The rationale for this is as follows:

— Firstly, the committee members felt that in practice there existed an important and un-stated safety characteristic with this type of connection. Whereby if the respiratory tubing becomes occluded the increase in pressure within the system will cause the elastomeric funnel to detach automatically from the nipple defined in Annex B.

— Secondly, the test only assesses the retention when the elastomeric funnel is assembled with 45N of force to the test nipple. This assembly force may not be adequate to ensure the funnel does not disconnect from the test nipple at full line pressures.

— Thirdly, a lower test pressure helps to ensure that the mechanical properties of the elastomeric funnel are not made too stiff and consequently too difficult for the user to connect and disconnect the elastomeric funnel from the nipple.

A.6.2.6   Respiratory tubing and extension tubing leakage

In 6.2.6, which assesses the leak properties of the tubing and connectors, the pressure is set at 600 kPa as this is the typical maximum pressure the tube may receive if blocked or kinked.

A.6.3.1   Respiratory tubing inlet connectors

Because of the flexibility of the elastomeric funnel connector the dimensions are not defined. This is left to manufacturer’s discretion as they need to assess the specified requirements for connection to the test nipple.

The specially convened ISO/TC 121 Working Group 1, (WG1), proposal on the connectors for therapy devices is to be published as a Technical Specification (TS). This specifies that options for the outlet of the gas supply device includes both the nipple and threaded gas-specific connectors for air or oxygen. This document therefore includes the same alternatives for the inlet of the respiratory tubing and specifies the disconnection force for the elastomeric funnel connector from a test nipple.

1. 
   (normative)
   
   Respiratory therapy equipment and tubing connectors

a) Nipple profile

b) Example of a nipple with corrugations within the nipple profile specified in Figure B.1 a)

Figure B.1 — Nipples for respiratory therapy equipment

Table B.1 — Dimensions of nipple

Figure B.2 — Gas-specific inlet connectors

NOTE 1: Dimensions and tolerances of all components of the oxygen and air gas-specific connectors, are specified in CGA V-5:2005,^[3] connection n. 1240.

NOTE 2: The inlet connectors are only the nuts and nipples. The threaded mating connector is only shown to provide the mating dimensions as given in CGA V-5:2005 ^[3]

1. 
   (informative)
   
   Hazard identification for the purposes of risk assessment
   1. General

This list is not intended to be comprehensive for all devices within the scope of this document, but to provide guidance for risk assessment.

• 1. Patient harm/lack of therapy associated with the use of respiratory therapy tubing and connectors

a) inhalation of toxic substances, leached from material.

b) inhalation of toxic substances, cleanliness, sterility.

c) transfer of bacterial infection between uses.

d) blockage of lumen.

Bibliography

[1] ISO DTS 22175, Connectors for respiratory devices (Yet to be published)

[2] EN 13544‑2:2009, Respiratory therapy equipment – Part 2 tubing and connectors

[3] CGA V- 5:2005, Diameter index safety (noninterchangeable low pressure connections for medical gas applications)

1. ISO 80369-2 is at FDIS stage at the time of publication of this document. ↑