1、BRITISH STANDARD BS ISO TR 11991:1995 Implementation of ISO TR 11991:1995 Guidance on airway management during laser surgery of upper airway ICS 11.040.10BSISOTR11991:1995 This British Standard, having been prepared under the directionof the Health and Environment Sector Board, waspublished under th
2、e authorityof the Standards Boardand comes into effect on 15 February 1997 BSI 12-1998 The following BSI references relate to the work on this standard: Committee reference CH/45 Draftannounced in BSI Update December 1996 ISBN 0 580 26625 7 Committees responsible for this British Standard The prepar
3、ation of this British Standard was entrusted to Technical Committee CH/45, Tracheal tubes and related equipment, upon which the following bodies were represented: Association of Anaesthetists of Great Britain and Ireland Association of British Health-care Industries British Anaesthetic and Respirato
4、ry Equipment Manufacturers Association British Paediatric Association British Surgical Trades Association Department of Health Medical Sterile Products Association National Association of Theatre Nurses Amendments issued since publication Amd. No. Date CommentsBSISOTR11991:1995 BSI 12-1998 i Content
5、s Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO TR 11991 1 Annex A Bibliography Inside back coverBSISOTR11991:1995 ii BSI 12-1998 National foreword This British Standard reproduces verbatimISO TR 11991:1995 and implements it as the UK national standard.
6、 This British Standard is published under the direction of the Health and Environment Sector Board whose Technical Committee CH/45 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for cha
7、nge, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. A British Standard do
8、es not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an ins
9、ide front cover, pages i and ii, theISOtitle page, pages ii to iv, pages 1 to 6, an inside back cover and abackcover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BSISOTR11991:1995
10、 ii BSI 12-1998 Contents Page Introduction 1 1 Scope 1 2 References 1 3 Terminology 1 4 Ideal properties of tracheal tubes for use with lasers 2 4.1 Materials 2 4.2 Design 2 4.3 Packaging and labelling 2 5 Description of current practices which reduce the risk of airway fire 2 5.1 Non-intubation tec
11、hniques 2 5.2 Intubation techniques 3 5.3 Management of airway fires 6 Table 1 Combustion properties of conventional tracheal tube materials 6 Table 2 Primary emergency management following recognition of airway fire 6 Table 3 Secondary emergency management following recognition of anairwayfire 6BSI
12、SOTR11991:1995 BSI 12-1998 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 ISO technical committees. Each member body intere
13、sted 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
14、Commission (IEC) on all matters of electrotechnical standardization. The main task of technical committees is to prepare International Standards, but in exceptional circumstances a technical committee may propose the publication of a Technical Report of one of the following types: type 1, when the r
15、equired support cannot be obtained for the publication of an International Standard, despite repeated efforts; type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; t
16、ype 3, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be tra
17、nsformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed until the data they provide are considered to be no longer valid or useful. ISO/TR 11991, which is a Technical Report of type3, was prepared by Technical CommitteeISO/TC 121, Anaesthetic and res
18、piratory equipment, Subcommittee SC2, Tracheal tubes and other equipment. This document is being issued as a type3 Technical Report to summarize current methods for airway management during laser surgery of the upper airway to minimize the risk of fire. (See the Introduction.)iv blankBSISOTR11991:19
19、95 BSI 12-1998 1 Introduction This guide provides information for clinicians for appropriate selection of airway devices for operations on the upper airway, including the larynx, in which a laser is used. It also provides information for the appropriate selection of intubation and non-intubation tec
20、hniques. Tracheal tubes are commonly used in patients during general anaesthesia for such operations. These tubes provide effective control of ventilation and oxygenation, protect the airway from aspiration (ifcuffed), and allow monitoring of ventilation through capnography and spirometry. A laser i
21、s a source of intense light energy which can provide an ignition source, so that a fire is a risk in the operative field. Risk of fire is particularly enhanced in oxidant (O 2or N 2 O) enriched atmospheres. Tracheal tubes assist ventilation and patient monitoring but may be ignited by the laser in t
22、hese circumstances. In these procedures, the clinician must be aware of the risk of fire. Fire requires three elements: an ignition source, a combustible material, and an oxygen source. These three are sometimes referred to as “the fire triangle”. During laser surgery on the upper airway, all three
23、elements are often present. The laser is an intense light energy which can provide a source of ignition. Tracheal tubes when present are usually made of combustible material. Finally, most patients are treated in an oxidant-enriched atmosphere. Care to minimize these three elements is essential to a
24、void a fire during laser surgery of the upper airway. Of the numerous methods available for airway management during laser operations on the upper airway, each has its own risks and advantages. This guide summarizes the current methods and the applications, advantages, and disadvantages of each. The
25、 guide serves to assist the anaesthetist and surgeon in their joint decision regarding selection of the most appropriate method to oxygenate and ventilate the patient during laser surgery involving the upper airway. This guide does not recommend any one method of airway management. The test data inc
26、luded inTable 1 of this guide are based upon continuous beam CO 2Lasers. While this data may not be directly applicable to other wavelengths or beam modes (such as super pulse), the basic principles still apply. Decisions regarding practice methods can only be made by the clinicians caring for the p
27、atient, having knowledge of the clinical circumstances, available expertise, and technology, e.g.the properties of the specific laser wavelength planned for the surgery. Other complications of laser surgery not involving airway management may be found in ANSI Z136.1 (1), and ANSI Z136.3 (2), CAN/CSA
28、 Z386 M91 (3). 1 Scope At present there is no way to avoid completely the risk of an airway fire when a laser is used in the airway. This guide is intended to help minimize this risk by listing a) those characteristics of a tracheal tube that make it most suitable for laser airway operations, recogn
29、izing that it may not be possible in practice to produce a device combining such characteristics; b) several standard practices that reduce the risk of airway fire during laser operations on the airway; c) recommendations for emergency management should an airway fire occur. This guide represents cu
30、rrent knowledge at the time of publication and is subject to review. This guide does not address management of the patient with a tracheostomy. This guide is also intended to assist related groups, such as laser safety committees. 2 References ISO 5361-1:1988, Tracheal tubes Part 1: General requirem
31、ents. ISO 5361-2:1993, Tracheal tubes Part 2: Oro-tracheal and naso-tracheal tubes of Magill type (plain and cuffed). ISO 5361-5:1984, Tracheal tubes Part5:Requirements and methods of test for cuffs and tubes. ISO 7228:1993, Tracheal tube connectors. ISO 10993-1: 1) , Biological evaluation of medica
32、l devices Part 1: Evaluation and testing. 3 Terminology For the purpose of this technical report, the following definitions apply. 3.1 anatomical airway: Natural pathways through which respired gases pass in either direction between the atmosphere and the alveoli. 3.2 combustion: Rapid oxidation to
33、produce heat and light. 3.3 F 1 O 2 : The fractional concentration of oxygen in inspired gas. 3.4 flammability: The ability to sustain combustion. 1) To be published. (Revision of ISO 10993-1:1992)BSISOTR11991:1995 2 BSI 12-1998 3.5 ignitability: The ability to initiate combustion. 3.6 intubation: P
34、lacement of a tracheal tube into the trachea. 3.7 laser platform: A surgical handpiece made of a non-combustible material with a non-reflective surface. The end of the device is placed behind the target tissue as a backstop for the laser. 3.8 laser plume: Gaseous and particulate by-products of combu
35、stion and/or pyrolysis produced by the effect of laser energy upon a target. 3.9 oxidant enriched atmosphere: Any atmosphere that contains oxidants (O 2 , N 2 O) in total concentration greater than 25% of volume at ambient pressure. 3.10 oxygen index of flammability: The minimum concentration of O 2
36、in N 2necessary to support a candle-like flame for a given substance. 3.11 pledget (cottonoid): A compress, usually of gauze or absorbent cotton. 3.12 power density (irradiance): The power delivered by a laser beam per unit area of irradiated surface (spot size), expressed as watts per square centim
37、etre. 3.13 pyrolysis: Transformation of a compound into one or more other substances by heat alone (without oxidation). 3.14 specular reflectance: The characteristics of a material to reflect light in such a way that the angle of reflection is equal to the angle of incidence, such as the reflectance
38、 from a mirror. 3.15 thermal conductivity: Time rate of heat flow through unit area, per unit temperature gradient, in the direction perpendicular to the area. 3.16 upper anatomical airway (the upper airway): The airway above the laryngotracheal junction. 4 Ideal properties of tracheal tubes for use
39、 with lasers 4.1 Materials The materials used for the manufacture of the part of the tracheal tube intended to lie in the upper airway should have the following characteristics: 4.1.1 Ignitability Materials should be resistant to ignition by a laser beam in the presence of 100% O 2 . 4.1.2 Flammabil
40、ity Materials should not maintain combustion in100%O 2 . 4.1.3 Specular reflectance Materials should have no specular reflectance so as to avoid injury to non-targeted tissue. 4.1.4 Heat transfer Materials should minimize heat transfer that may damage adjacent tissue. 4.1.5 Products of pyrolysis and
41、 combustion The products of pyrolysis and combustion should satisfy appropriate biological safety test as specified inISO 10993-1. 4.2 Design 4.2.1 General Tubes should comply with the requirements specified inISO 5361-1, ISO5361-2, ISO 5361-5 and ISO 7228. 4.2.2 Integrity In the event of tube ignit
42、ion, integrity of the tube and attached components should be maintained so that they can be immediately removed intact. 4.2.3 Transparency The material used for the manufacture of the tracheal tube should be sufficiently optically transparent or translucent to enable condensation of airway vapour an
43、d evidence of combustion to be seen within its lumen. 4.2.4 Cuff inflation The tracheal tube cuff should be capable of being inflated with liquid and rapidly deflated under normal conditions of use. 4.2.5 The cuff and inflation system The cuff and inflation system, if exposed, should be laser resist
44、ant. 4.3 Packaging and labelling 4.3.1 The tracheal tube and attached components should be preassembled and individually packaged. 4.3.2 The tube should be intended and labelled for single use. 5 Description of current practices which reduce the risk of airway fire At present there is no way to comp
45、letely avoid the risk of an airway fire when a laser is used in the airway. The following are descriptions of current practices that reduce the risk of airway fire. Accompanying each practice is a discussion of its advantages and disadvantages. No significance should be attributed to the order in wh
46、ich these practices are presented. 5.1 Non-intubation techniques These methods of ventilation do not use a tracheal tube.BSISOTR11991:1995 BSI 12-1998 3 5.1.1 Spontaneous breathing techniques With the patient breathing spontaneously, gas with or without supplemental oxygen and/or potent inhalation a
47、naesthetic is insufflated into the operating laryngoscope, bronchoscope, a metal hook, or a catheter(4). The anaesthetic may be supplemented with intravenous agents and/or regional anaesthesia to the airway. Advantages: There is no tracheal tube in the airway so that the risk of fire is reduced. The
48、 method also provides excellent visibility of the surgical field and avoids potential trauma to the airway that use of a tracheal tube might cause. Disadvantages: Hypoventilation is a risk which may go undetected since capnography is difficult and inaccurate, and spirometry cannot be used. Pulmonary
49、 aspiration of gastric contents and/or laser plume can also occur. Ventilation cannot be assisted or controlled. Depth of anaesthesia may fluctuate so that patient movement can occur. Insufflation techniques make scavenging anaesthetic gases difficult. The risk of fire is increased if a flammable catheter is used as the insufflation device. 5.1.2 Apnoeic techniques The patient is ventilated through a mask, tracheal tube, or bronchoscope, using oxygen-enriched gas, with or without potent inhalation anaesthetic. During ventilation, the laser is not used
